1Porting Guide 2============= 3 4Introduction 5------------ 6 7Porting Trusted Firmware-A (TF-A) to a new platform involves making some 8mandatory and optional modifications for both the cold and warm boot paths. 9Modifications consist of: 10 11- Implementing a platform-specific function or variable, 12- Setting up the execution context in a certain way, or 13- Defining certain constants (for example #defines). 14 15The platform-specific functions and variables are declared in 16``include/plat/common/platform.h``. The firmware provides a default 17implementation of variables and functions to fulfill the optional requirements 18in order to ease the porting effort. Each platform port can use them as is or 19provide their own implementation if the default implementation is inadequate. 20 21 .. note:: 22 23 TF-A historically provided default implementations of platform interfaces 24 as *weak* functions. This practice is now discouraged and new platform 25 interfaces as they get introduced in the code base should be *strongly* 26 defined. We intend to convert existing weak functions over time. Until 27 then, you will find references to *weak* functions in this document. 28 29Please review the :ref:`Threat Model` documents as part of the porting 30effort. Some platform interfaces play a key role in mitigating against some of 31the threats. Failing to fulfill these expectations could undermine the security 32guarantees offered by TF-A. These platform responsibilities are highlighted in 33the threat assessment section, under the "`Mitigations implemented?`" box for 34each threat. 35 36Some modifications are common to all Boot Loader (BL) stages. Section 2 37discusses these in detail. The subsequent sections discuss the remaining 38modifications for each BL stage in detail. 39 40Please refer to the :ref:`Platform Ports Policy` for the policy regarding 41compatibility and deprecation of these porting interfaces. 42 43Only Arm development platforms (such as FVP and Juno) may use the 44functions/definitions in ``include/plat/arm/common/`` and the corresponding 45source files in ``plat/arm/common/``. This is done so that there are no 46dependencies between platforms maintained by different people/companies. If you 47want to use any of the functionality present in ``plat/arm`` files, please 48propose a patch that moves the code to ``plat/common`` so that it can be 49discussed. 50 51Common modifications 52-------------------- 53 54This section covers the modifications that should be made by the platform for 55each BL stage to correctly port the firmware stack. They are categorized as 56either mandatory or optional. 57 58Common mandatory modifications 59------------------------------ 60 61A platform port must enable the Memory Management Unit (MMU) as well as the 62instruction and data caches for each BL stage. Setting up the translation 63tables is the responsibility of the platform port because memory maps differ 64across platforms. A memory translation library (see ``lib/xlat_tables_v2/``) is 65provided to help in this setup. 66 67Note that although this library supports non-identity mappings, this is intended 68only for re-mapping peripheral physical addresses and allows platforms with high 69I/O addresses to reduce their virtual address space. All other addresses 70corresponding to code and data must currently use an identity mapping. 71 72Also, the only translation granule size supported in TF-A is 4KB, as various 73parts of the code assume that is the case. It is not possible to switch to 7416 KB or 64 KB granule sizes at the moment. 75 76In Arm standard platforms, each BL stage configures the MMU in the 77platform-specific architecture setup function, ``blX_plat_arch_setup()``, and uses 78an identity mapping for all addresses. 79 80If the build option ``USE_COHERENT_MEM`` is enabled, each platform can allocate a 81block of identity mapped secure memory with Device-nGnRE attributes aligned to 82page boundary (4K) for each BL stage. All sections which allocate coherent 83memory are grouped under ``.coherent_ram``. For ex: Bakery locks are placed in a 84section identified by name ``.bakery_lock`` inside ``.coherent_ram`` so that its 85possible for the firmware to place variables in it using the following C code 86directive: 87 88:: 89 90 __section(".bakery_lock") 91 92Or alternatively the following assembler code directive: 93 94:: 95 96 .section .bakery_lock 97 98The ``.coherent_ram`` section is a sum of all sections like ``.bakery_lock`` which are 99used to allocate any data structures that are accessed both when a CPU is 100executing with its MMU and caches enabled, and when it's running with its MMU 101and caches disabled. Examples are given below. 102 103The following variables, functions and constants must be defined by the platform 104for the firmware to work correctly. 105 106.. _platform_def_mandatory: 107 108File : platform_def.h [mandatory] 109~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 110 111Each platform must ensure that a header file of this name is in the system 112include path with the following constants defined. This will require updating 113the list of ``PLAT_INCLUDES`` in the ``platform.mk`` file. 114 115Platform ports may optionally use the file ``include/plat/common/common_def.h``, 116which provides typical values for some of the constants below. These values are 117likely to be suitable for all platform ports. 118 119- **#define : PLATFORM_LINKER_FORMAT** 120 121 Defines the linker format used by the platform, for example 122 ``elf64-littleaarch64``. 123 124- **#define : PLATFORM_LINKER_ARCH** 125 126 Defines the processor architecture for the linker by the platform, for 127 example ``aarch64``. 128 129- **#define : PLATFORM_STACK_SIZE** 130 131 Defines the normal stack memory available to each CPU. This constant is used 132 by ``plat/common/aarch64/platform_mp_stack.S`` and 133 ``plat/common/aarch64/platform_up_stack.S``. 134 135- **#define : CACHE_WRITEBACK_GRANULE** 136 137 Defines the size in bytes of the largest cache line across all the cache 138 levels in the platform. 139 140- **#define : FIRMWARE_WELCOME_STR** 141 142 Defines the character string printed by BL1 upon entry into the ``bl1_main()`` 143 function. 144 145- **#define : PLATFORM_CORE_COUNT** 146 147 Defines the total number of CPUs implemented by the platform across all 148 clusters in the system. 149 150- **#define : PLAT_NUM_PWR_DOMAINS** 151 152 Defines the total number of nodes in the power domain topology 153 tree at all the power domain levels used by the platform. 154 This macro is used by the PSCI implementation to allocate 155 data structures to represent power domain topology. 156 157- **#define : PLAT_MAX_PWR_LVL** 158 159 Defines the maximum power domain level that the power management operations 160 should apply to. More often, but not always, the power domain level 161 corresponds to affinity level. This macro allows the PSCI implementation 162 to know the highest power domain level that it should consider for power 163 management operations in the system that the platform implements. For 164 example, the Base AEM FVP implements two clusters with a configurable 165 number of CPUs and it reports the maximum power domain level as 1. 166 167- **#define : PLAT_MAX_OFF_STATE** 168 169 Defines the local power state corresponding to the deepest power down 170 possible at every power domain level in the platform. The local power 171 states for each level may be sparsely allocated between 0 and this value 172 with 0 being reserved for the RUN state. The PSCI implementation uses this 173 value to initialize the local power states of the power domain nodes and 174 to specify the requested power state for a PSCI_CPU_OFF call. 175 176- **#define : PLAT_MAX_RET_STATE** 177 178 Defines the local power state corresponding to the deepest retention state 179 possible at every power domain level in the platform. This macro should be 180 a value less than PLAT_MAX_OFF_STATE and greater than 0. It is used by the 181 PSCI implementation to distinguish between retention and power down local 182 power states within PSCI_CPU_SUSPEND call. 183 184- **#define : PLAT_MAX_PWR_LVL_STATES** 185 186 Defines the maximum number of local power states per power domain level 187 that the platform supports. The default value of this macro is 2 since 188 most platforms just support a maximum of two local power states at each 189 power domain level (power-down and retention). If the platform needs to 190 account for more local power states, then it must redefine this macro. 191 192 Currently, this macro is used by the Generic PSCI implementation to size 193 the array used for PSCI_STAT_COUNT/RESIDENCY accounting. 194 195- **#define : BL1_RO_BASE** 196 197 Defines the base address in secure ROM where BL1 originally lives. Must be 198 aligned on a page-size boundary. 199 200- **#define : BL1_RO_LIMIT** 201 202 Defines the maximum address in secure ROM that BL1's actual content (i.e. 203 excluding any data section allocated at runtime) can occupy. 204 205- **#define : BL1_RW_BASE** 206 207 Defines the base address in secure RAM where BL1's read-write data will live 208 at runtime. Must be aligned on a page-size boundary. 209 210- **#define : BL1_RW_LIMIT** 211 212 Defines the maximum address in secure RAM that BL1's read-write data can 213 occupy at runtime. 214 215- **#define : BL2_BASE** 216 217 Defines the base address in secure RAM where BL1 loads the BL2 binary image. 218 Must be aligned on a page-size boundary. This constant is not applicable 219 when BL2_IN_XIP_MEM is set to '1'. 220 221- **#define : BL2_LIMIT** 222 223 Defines the maximum address in secure RAM that the BL2 image can occupy. 224 This constant is not applicable when BL2_IN_XIP_MEM is set to '1'. 225 226- **#define : BL2_RO_BASE** 227 228 Defines the base address in secure XIP memory where BL2 RO section originally 229 lives. Must be aligned on a page-size boundary. This constant is only needed 230 when BL2_IN_XIP_MEM is set to '1'. 231 232- **#define : BL2_RO_LIMIT** 233 234 Defines the maximum address in secure XIP memory that BL2's actual content 235 (i.e. excluding any data section allocated at runtime) can occupy. This 236 constant is only needed when BL2_IN_XIP_MEM is set to '1'. 237 238- **#define : BL2_RW_BASE** 239 240 Defines the base address in secure RAM where BL2's read-write data will live 241 at runtime. Must be aligned on a page-size boundary. This constant is only 242 needed when BL2_IN_XIP_MEM is set to '1'. 243 244- **#define : BL2_RW_LIMIT** 245 246 Defines the maximum address in secure RAM that BL2's read-write data can 247 occupy at runtime. This constant is only needed when BL2_IN_XIP_MEM is set 248 to '1'. 249 250- **#define : BL31_BASE** 251 252 Defines the base address in secure RAM where BL2 loads the BL31 binary 253 image. Must be aligned on a page-size boundary. 254 255- **#define : BL31_LIMIT** 256 257 Defines the maximum address in secure RAM that the BL31 image can occupy. 258 259- **#define : PLAT_RSE_COMMS_PAYLOAD_MAX_SIZE** 260 261 Defines the maximum message size between AP and RSE. Need to define if 262 platform supports RSE. 263 264For every image, the platform must define individual identifiers that will be 265used by BL1 or BL2 to load the corresponding image into memory from non-volatile 266storage. For the sake of performance, integer numbers will be used as 267identifiers. The platform will use those identifiers to return the relevant 268information about the image to be loaded (file handler, load address, 269authentication information, etc.). The following image identifiers are 270mandatory: 271 272- **#define : BL2_IMAGE_ID** 273 274 BL2 image identifier, used by BL1 to load BL2. 275 276- **#define : BL31_IMAGE_ID** 277 278 BL31 image identifier, used by BL2 to load BL31. 279 280- **#define : BL33_IMAGE_ID** 281 282 BL33 image identifier, used by BL2 to load BL33. 283 284If Trusted Board Boot is enabled, the following certificate identifiers must 285also be defined: 286 287- **#define : TRUSTED_BOOT_FW_CERT_ID** 288 289 BL2 content certificate identifier, used by BL1 to load the BL2 content 290 certificate. 291 292- **#define : TRUSTED_KEY_CERT_ID** 293 294 Trusted key certificate identifier, used by BL2 to load the trusted key 295 certificate. 296 297- **#define : SOC_FW_KEY_CERT_ID** 298 299 BL31 key certificate identifier, used by BL2 to load the BL31 key 300 certificate. 301 302- **#define : SOC_FW_CONTENT_CERT_ID** 303 304 BL31 content certificate identifier, used by BL2 to load the BL31 content 305 certificate. 306 307- **#define : NON_TRUSTED_FW_KEY_CERT_ID** 308 309 BL33 key certificate identifier, used by BL2 to load the BL33 key 310 certificate. 311 312- **#define : NON_TRUSTED_FW_CONTENT_CERT_ID** 313 314 BL33 content certificate identifier, used by BL2 to load the BL33 content 315 certificate. 316 317- **#define : FWU_CERT_ID** 318 319 Firmware Update (FWU) certificate identifier, used by NS_BL1U to load the 320 FWU content certificate. 321 322If the AP Firmware Updater Configuration image, BL2U is used, the following 323must also be defined: 324 325- **#define : BL2U_BASE** 326 327 Defines the base address in secure memory where BL1 copies the BL2U binary 328 image. Must be aligned on a page-size boundary. 329 330- **#define : BL2U_LIMIT** 331 332 Defines the maximum address in secure memory that the BL2U image can occupy. 333 334- **#define : BL2U_IMAGE_ID** 335 336 BL2U image identifier, used by BL1 to fetch an image descriptor 337 corresponding to BL2U. 338 339If the SCP Firmware Update Configuration Image, SCP_BL2U is used, the following 340must also be defined: 341 342- **#define : SCP_BL2U_IMAGE_ID** 343 344 SCP_BL2U image identifier, used by BL1 to fetch an image descriptor 345 corresponding to SCP_BL2U. 346 347 .. note:: 348 TF-A does not provide source code for this image. 349 350If the Non-Secure Firmware Updater ROM, NS_BL1U is used, the following must 351also be defined: 352 353- **#define : NS_BL1U_BASE** 354 355 Defines the base address in non-secure ROM where NS_BL1U executes. 356 Must be aligned on a page-size boundary. 357 358 .. note:: 359 TF-A does not provide source code for this image. 360 361- **#define : NS_BL1U_IMAGE_ID** 362 363 NS_BL1U image identifier, used by BL1 to fetch an image descriptor 364 corresponding to NS_BL1U. 365 366If the Non-Secure Firmware Updater, NS_BL2U is used, the following must also 367be defined: 368 369- **#define : NS_BL2U_BASE** 370 371 Defines the base address in non-secure memory where NS_BL2U executes. 372 Must be aligned on a page-size boundary. 373 374 .. note:: 375 TF-A does not provide source code for this image. 376 377- **#define : NS_BL2U_IMAGE_ID** 378 379 NS_BL2U image identifier, used by BL1 to fetch an image descriptor 380 corresponding to NS_BL2U. 381 382For the the Firmware update capability of TRUSTED BOARD BOOT, the following 383macros may also be defined: 384 385- **#define : PLAT_FWU_MAX_SIMULTANEOUS_IMAGES** 386 387 Total number of images that can be loaded simultaneously. If the platform 388 doesn't specify any value, it defaults to 10. 389 390If a SCP_BL2 image is supported by the platform, the following constants must 391also be defined: 392 393- **#define : SCP_BL2_IMAGE_ID** 394 395 SCP_BL2 image identifier, used by BL2 to load SCP_BL2 into secure memory 396 from platform storage before being transferred to the SCP. 397 398- **#define : SCP_FW_KEY_CERT_ID** 399 400 SCP_BL2 key certificate identifier, used by BL2 to load the SCP_BL2 key 401 certificate (mandatory when Trusted Board Boot is enabled). 402 403- **#define : SCP_FW_CONTENT_CERT_ID** 404 405 SCP_BL2 content certificate identifier, used by BL2 to load the SCP_BL2 406 content certificate (mandatory when Trusted Board Boot is enabled). 407 408If a BL32 image is supported by the platform, the following constants must 409also be defined: 410 411- **#define : BL32_IMAGE_ID** 412 413 BL32 image identifier, used by BL2 to load BL32. 414 415- **#define : TRUSTED_OS_FW_KEY_CERT_ID** 416 417 BL32 key certificate identifier, used by BL2 to load the BL32 key 418 certificate (mandatory when Trusted Board Boot is enabled). 419 420- **#define : TRUSTED_OS_FW_CONTENT_CERT_ID** 421 422 BL32 content certificate identifier, used by BL2 to load the BL32 content 423 certificate (mandatory when Trusted Board Boot is enabled). 424 425- **#define : BL32_BASE** 426 427 Defines the base address in secure memory where BL2 loads the BL32 binary 428 image. Must be aligned on a page-size boundary. 429 430- **#define : BL32_LIMIT** 431 432 Defines the maximum address that the BL32 image can occupy. 433 434If the Test Secure-EL1 Payload (TSP) instantiation of BL32 is supported by the 435platform, the following constants must also be defined: 436 437- **#define : TSP_SEC_MEM_BASE** 438 439 Defines the base address of the secure memory used by the TSP image on the 440 platform. This must be at the same address or below ``BL32_BASE``. 441 442- **#define : TSP_SEC_MEM_SIZE** 443 444 Defines the size of the secure memory used by the BL32 image on the 445 platform. ``TSP_SEC_MEM_BASE`` and ``TSP_SEC_MEM_SIZE`` must fully 446 accommodate the memory required by the BL32 image, defined by ``BL32_BASE`` 447 and ``BL32_LIMIT``. 448 449- **#define : TSP_IRQ_SEC_PHY_TIMER** 450 451 Defines the ID of the secure physical generic timer interrupt used by the 452 TSP's interrupt handling code. 453 454If the platform port uses the translation table library code, the following 455constants must also be defined: 456 457- **#define : PLAT_XLAT_TABLES_DYNAMIC** 458 459 Optional flag that can be set per-image to enable the dynamic allocation of 460 regions even when the MMU is enabled. If not defined, only static 461 functionality will be available, if defined and set to 1 it will also 462 include the dynamic functionality. 463 464- **#define : MAX_XLAT_TABLES** 465 466 Defines the maximum number of translation tables that are allocated by the 467 translation table library code. To minimize the amount of runtime memory 468 used, choose the smallest value needed to map the required virtual addresses 469 for each BL stage. If ``PLAT_XLAT_TABLES_DYNAMIC`` flag is enabled for a BL 470 image, ``MAX_XLAT_TABLES`` must be defined to accommodate the dynamic regions 471 as well. 472 473- **#define : MAX_MMAP_REGIONS** 474 475 Defines the maximum number of regions that are allocated by the translation 476 table library code. A region consists of physical base address, virtual base 477 address, size and attributes (Device/Memory, RO/RW, Secure/Non-Secure), as 478 defined in the ``mmap_region_t`` structure. The platform defines the regions 479 that should be mapped. Then, the translation table library will create the 480 corresponding tables and descriptors at runtime. To minimize the amount of 481 runtime memory used, choose the smallest value needed to register the 482 required regions for each BL stage. If ``PLAT_XLAT_TABLES_DYNAMIC`` flag is 483 enabled for a BL image, ``MAX_MMAP_REGIONS`` must be defined to accommodate 484 the dynamic regions as well. 485 486- **#define : PLAT_VIRT_ADDR_SPACE_SIZE** 487 488 Defines the total size of the virtual address space in bytes. For example, 489 for a 32 bit virtual address space, this value should be ``(1ULL << 32)``. 490 491- **#define : PLAT_PHY_ADDR_SPACE_SIZE** 492 493 Defines the total size of the physical address space in bytes. For example, 494 for a 32 bit physical address space, this value should be ``(1ULL << 32)``. 495 496If the platform port uses the IO storage framework, the following constants 497must also be defined: 498 499- **#define : MAX_IO_DEVICES** 500 501 Defines the maximum number of registered IO devices. Attempting to register 502 more devices than this value using ``io_register_device()`` will fail with 503 -ENOMEM. 504 505- **#define : MAX_IO_HANDLES** 506 507 Defines the maximum number of open IO handles. Attempting to open more IO 508 entities than this value using ``io_open()`` will fail with -ENOMEM. 509 510- **#define : MAX_IO_BLOCK_DEVICES** 511 512 Defines the maximum number of registered IO block devices. Attempting to 513 register more devices this value using ``io_dev_open()`` will fail 514 with -ENOMEM. MAX_IO_BLOCK_DEVICES should be less than MAX_IO_DEVICES. 515 With this macro, multiple block devices could be supported at the same 516 time. 517 518If the platform needs to allocate data within the per-cpu data framework in 519BL31, it should define the following macro. Currently this is only required if 520the platform decides not to use the coherent memory section by undefining the 521``USE_COHERENT_MEM`` build flag. In this case, the framework allocates the 522required memory within the the per-cpu data to minimize wastage. 523 524- **#define : PLAT_PCPU_DATA_SIZE** 525 526 Defines the memory (in bytes) to be reserved within the per-cpu data 527 structure for use by the platform layer. 528 529The following constants are optional. They should be defined when the platform 530memory layout implies some image overlaying like in Arm standard platforms. 531 532- **#define : BL31_PROGBITS_LIMIT** 533 534 Defines the maximum address in secure RAM that the BL31's progbits sections 535 can occupy. 536 537- **#define : TSP_PROGBITS_LIMIT** 538 539 Defines the maximum address that the TSP's progbits sections can occupy. 540 541If the platform supports OS-initiated mode, i.e. the build option 542``PSCI_OS_INIT_MODE`` is enabled, and if the platform's maximum power domain 543level for PSCI_CPU_SUSPEND differs from ``PLAT_MAX_PWR_LVL``, the following 544constant must be defined. 545 546- **#define : PLAT_MAX_CPU_SUSPEND_PWR_LVL** 547 548 Defines the maximum power domain level that PSCI_CPU_SUSPEND should apply to. 549 550If the platform port uses the PL061 GPIO driver, the following constant may 551optionally be defined: 552 553- **PLAT_PL061_MAX_GPIOS** 554 Maximum number of GPIOs required by the platform. This allows control how 555 much memory is allocated for PL061 GPIO controllers. The default value is 556 557 #. $(eval $(call add_define,PLAT_PL061_MAX_GPIOS)) 558 559If the platform port uses the partition driver, the following constant may 560optionally be defined: 561 562- **PLAT_PARTITION_MAX_ENTRIES** 563 Maximum number of partition entries required by the platform. This allows 564 control how much memory is allocated for partition entries. The default 565 value is 128. 566 For example, define the build flag in ``platform.mk``: 567 PLAT_PARTITION_MAX_ENTRIES := 12 568 $(eval $(call add_define,PLAT_PARTITION_MAX_ENTRIES)) 569 570- **PLAT_PARTITION_BLOCK_SIZE** 571 The size of partition block. It could be either 512 bytes or 4096 bytes. 572 The default value is 512. 573 For example, define the build flag in ``platform.mk``: 574 PLAT_PARTITION_BLOCK_SIZE := 4096 575 $(eval $(call add_define,PLAT_PARTITION_BLOCK_SIZE)) 576 577If the platform port uses the Arm® Ethos™-N NPU driver, the following 578configuration must be performed: 579 580- The NPU SiP service handler must be hooked up. This consists of both the 581 initial setup (``ethosn_smc_setup``) and the handler itself 582 (``ethosn_smc_handler``) 583 584If the platform port uses the Arm® Ethos™-N NPU driver with TZMP1 support 585enabled, the following constants and configuration must also be defined: 586 587- **ETHOSN_NPU_PROT_FW_NSAID** 588 589 Defines the Non-secure Access IDentity (NSAID) that the NPU shall use to 590 access the protected memory that contains the NPU's firmware. 591 592- **ETHOSN_NPU_PROT_DATA_RW_NSAID** 593 594 Defines the Non-secure Access IDentity (NSAID) that the NPU shall use for 595 read/write access to the protected memory that contains inference data. 596 597- **ETHOSN_NPU_PROT_DATA_RO_NSAID** 598 599 Defines the Non-secure Access IDentity (NSAID) that the NPU shall use for 600 read-only access to the protected memory that contains inference data. 601 602- **ETHOSN_NPU_NS_RW_DATA_NSAID** 603 604 Defines the Non-secure Access IDentity (NSAID) that the NPU shall use for 605 read/write access to the non-protected memory. 606 607- **ETHOSN_NPU_NS_RO_DATA_NSAID** 608 609 Defines the Non-secure Access IDentity (NSAID) that the NPU shall use for 610 read-only access to the non-protected memory. 611 612- **ETHOSN_NPU_FW_IMAGE_BASE** and **ETHOSN_NPU_FW_IMAGE_LIMIT** 613 614 Defines the physical address range that the NPU's firmware will be loaded 615 into and executed from. 616 617- Configure the platforms TrustZone Controller (TZC) with appropriate regions 618 of protected memory. At minimum this must include a region for the NPU's 619 firmware code and a region for protected inference data, and these must be 620 accessible using the NSAIDs defined above. 621 622- Include the NPU firmware and certificates in the FIP. 623 624- Provide FCONF entries to configure the image source for the NPU firmware 625 and certificates. 626 627- Add MMU mappings such that: 628 629 - BL2 can write the NPU firmware into the region defined by 630 ``ETHOSN_NPU_FW_IMAGE_BASE`` and ``ETHOSN_NPU_FW_IMAGE_LIMIT`` 631 - BL31 (SiP service) can read the NPU firmware from the same region 632 633- Add the firmware image ID ``ETHOSN_NPU_FW_IMAGE_ID`` to the list of images 634 loaded by BL2. 635 636Please see the reference implementation code for the Juno platform as an example. 637 638 639The following constant is optional. It should be defined to override the default 640behaviour of the ``assert()`` function (for example, to save memory). 641 642- **PLAT_LOG_LEVEL_ASSERT** 643 If ``PLAT_LOG_LEVEL_ASSERT`` is higher or equal than ``LOG_LEVEL_VERBOSE``, 644 ``assert()`` prints the name of the file, the line number and the asserted 645 expression. Else if it is higher than ``LOG_LEVEL_INFO``, it prints the file 646 name and the line number. Else if it is lower than ``LOG_LEVEL_INFO``, it 647 doesn't print anything to the console. If ``PLAT_LOG_LEVEL_ASSERT`` isn't 648 defined, it defaults to ``LOG_LEVEL``. 649 650If the platform port uses the DRTM feature, the following constants must be 651defined: 652 653- **#define : PLAT_DRTM_EVENT_LOG_MAX_SIZE** 654 655 Maximum Event Log size used by the platform. Platform can decide the maximum 656 size of the Event Log buffer, depending upon the highest hash algorithm 657 chosen and the number of components selected to measure during the DRTM 658 execution flow. 659 660- **#define : PLAT_DRTM_MMAP_ENTRIES** 661 662 Number of the MMAP entries used by the DRTM implementation to calculate the 663 size of address map region of the platform. 664 665File : plat_macros.S [mandatory] 666~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 667 668Each platform must ensure a file of this name is in the system include path with 669the following macro defined. In the Arm development platforms, this file is 670found in ``plat/arm/board/<plat_name>/include/plat_macros.S``. 671 672- **Macro : plat_crash_print_regs** 673 674 This macro allows the crash reporting routine to print relevant platform 675 registers in case of an unhandled exception in BL31. This aids in debugging 676 and this macro can be defined to be empty in case register reporting is not 677 desired. 678 679 For instance, GIC or interconnect registers may be helpful for 680 troubleshooting. 681 682Handling Reset 683-------------- 684 685BL1 by default implements the reset vector where execution starts from a cold 686or warm boot. BL31 can be optionally set as a reset vector using the 687``RESET_TO_BL31`` make variable. 688 689For each CPU, the reset vector code is responsible for the following tasks: 690 691#. Distinguishing between a cold boot and a warm boot. 692 693#. In the case of a cold boot and the CPU being a secondary CPU, ensuring that 694 the CPU is placed in a platform-specific state until the primary CPU 695 performs the necessary steps to remove it from this state. 696 697#. In the case of a warm boot, ensuring that the CPU jumps to a platform- 698 specific address in the BL31 image in the same processor mode as it was 699 when released from reset. 700 701The following functions need to be implemented by the platform port to enable 702reset vector code to perform the above tasks. 703 704Function : plat_get_my_entrypoint() [mandatory when PROGRAMMABLE_RESET_ADDRESS == 0] 705~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 706 707:: 708 709 Argument : void 710 Return : uintptr_t 711 712This function is called with the MMU and caches disabled 713(``SCTLR_EL3.M`` = 0 and ``SCTLR_EL3.C`` = 0). The function is responsible for 714distinguishing between a warm and cold reset for the current CPU using 715platform-specific means. If it's a warm reset, then it returns the warm 716reset entrypoint point provided to ``plat_setup_psci_ops()`` during 717BL31 initialization. If it's a cold reset then this function must return zero. 718 719This function does not follow the Procedure Call Standard used by the 720Application Binary Interface for the Arm 64-bit architecture. The caller should 721not assume that callee saved registers are preserved across a call to this 722function. 723 724This function fulfills requirement 1 and 3 listed above. 725 726Note that for platforms that support programming the reset address, it is 727expected that a CPU will start executing code directly at the right address, 728both on a cold and warm reset. In this case, there is no need to identify the 729type of reset nor to query the warm reset entrypoint. Therefore, implementing 730this function is not required on such platforms. 731 732Function : plat_secondary_cold_boot_setup() [mandatory when COLD_BOOT_SINGLE_CPU == 0] 733~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 734 735:: 736 737 Argument : void 738 739This function is called with the MMU and data caches disabled. It is responsible 740for placing the executing secondary CPU in a platform-specific state until the 741primary CPU performs the necessary actions to bring it out of that state and 742allow entry into the OS. This function must not return. 743 744In the Arm FVP port, when using the normal boot flow, each secondary CPU powers 745itself off. The primary CPU is responsible for powering up the secondary CPUs 746when normal world software requires them. When booting an EL3 payload instead, 747they stay powered on and are put in a holding pen until their mailbox gets 748populated. 749 750This function fulfills requirement 2 above. 751 752Note that for platforms that can't release secondary CPUs out of reset, only the 753primary CPU will execute the cold boot code. Therefore, implementing this 754function is not required on such platforms. 755 756Function : plat_is_my_cpu_primary() [mandatory when COLD_BOOT_SINGLE_CPU == 0] 757~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 758 759:: 760 761 Argument : void 762 Return : unsigned int 763 764This function identifies whether the current CPU is the primary CPU or a 765secondary CPU. A return value of zero indicates that the CPU is not the 766primary CPU, while a non-zero return value indicates that the CPU is the 767primary CPU. 768 769Note that for platforms that can't release secondary CPUs out of reset, only the 770primary CPU will execute the cold boot code. Therefore, there is no need to 771distinguish between primary and secondary CPUs and implementing this function is 772not required. 773 774Function : platform_mem_init() [mandatory] 775~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 776 777:: 778 779 Argument : void 780 Return : void 781 782This function is called before any access to data is made by the firmware, in 783order to carry out any essential memory initialization. 784 785Function: plat_get_rotpk_info() 786~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 787 788:: 789 790 Argument : void *, void **, unsigned int *, unsigned int * 791 Return : int 792 793This function is mandatory when Trusted Board Boot is enabled. It returns a 794pointer to the ROTPK stored in the platform (or a hash of it) and its length. 795The ROTPK must be encoded in DER format according to the following ASN.1 796structure: 797 798:: 799 800 AlgorithmIdentifier ::= SEQUENCE { 801 algorithm OBJECT IDENTIFIER, 802 parameters ANY DEFINED BY algorithm OPTIONAL 803 } 804 805 SubjectPublicKeyInfo ::= SEQUENCE { 806 algorithm AlgorithmIdentifier, 807 subjectPublicKey BIT STRING 808 } 809 810In case the function returns a hash of the key: 811 812:: 813 814 DigestInfo ::= SEQUENCE { 815 digestAlgorithm AlgorithmIdentifier, 816 digest OCTET STRING 817 } 818 819The function returns 0 on success. Any other value is treated as error by the 820Trusted Board Boot. The function also reports extra information related 821to the ROTPK in the flags parameter: 822 823:: 824 825 ROTPK_IS_HASH : Indicates that the ROTPK returned by the platform is a 826 hash. 827 ROTPK_NOT_DEPLOYED : This allows the platform to skip certificate ROTPK 828 verification while the platform ROTPK is not deployed. 829 When this flag is set, the function does not need to 830 return a platform ROTPK, and the authentication 831 framework uses the ROTPK in the certificate without 832 verifying it against the platform value. This flag 833 must not be used in a deployed production environment. 834 835Function: plat_get_nv_ctr() 836~~~~~~~~~~~~~~~~~~~~~~~~~~~ 837 838:: 839 840 Argument : void *, unsigned int * 841 Return : int 842 843This function is mandatory when Trusted Board Boot is enabled. It returns the 844non-volatile counter value stored in the platform in the second argument. The 845cookie in the first argument may be used to select the counter in case the 846platform provides more than one (for example, on platforms that use the default 847TBBR CoT, the cookie will correspond to the OID values defined in 848TRUSTED_FW_NVCOUNTER_OID or NON_TRUSTED_FW_NVCOUNTER_OID). 849 850The function returns 0 on success. Any other value means the counter value could 851not be retrieved from the platform. 852 853Function: plat_set_nv_ctr() 854~~~~~~~~~~~~~~~~~~~~~~~~~~~ 855 856:: 857 858 Argument : void *, unsigned int 859 Return : int 860 861This function is mandatory when Trusted Board Boot is enabled. It sets a new 862counter value in the platform. The cookie in the first argument may be used to 863select the counter (as explained in plat_get_nv_ctr()). The second argument is 864the updated counter value to be written to the NV counter. 865 866The function returns 0 on success. Any other value means the counter value could 867not be updated. 868 869Function: plat_set_nv_ctr2() 870~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 871 872:: 873 874 Argument : void *, const auth_img_desc_t *, unsigned int 875 Return : int 876 877This function is optional when Trusted Board Boot is enabled. If this 878interface is defined, then ``plat_set_nv_ctr()`` need not be defined. The 879first argument passed is a cookie and is typically used to 880differentiate between a Non Trusted NV Counter and a Trusted NV 881Counter. The second argument is a pointer to an authentication image 882descriptor and may be used to decide if the counter is allowed to be 883updated or not. The third argument is the updated counter value to 884be written to the NV counter. 885 886The function returns 0 on success. Any other value means the counter value 887either could not be updated or the authentication image descriptor indicates 888that it is not allowed to be updated. 889 890Dynamic Root of Trust for Measurement support (in BL31) 891------------------------------------------------------- 892 893The functions mentioned in this section are mandatory, when platform enables 894DRTM_SUPPORT build flag. 895 896Function : plat_get_addr_mmap() 897~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 898 899:: 900 901 Argument : void 902 Return : const mmap_region_t * 903 904This function is used to return the address of the platform *address-map* table, 905which describes the regions of normal memory, memory mapped I/O 906and non-volatile memory. 907 908Function : plat_has_non_host_platforms() 909~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 910 911:: 912 913 Argument : void 914 Return : bool 915 916This function returns *true* if the platform has any trusted devices capable of 917DMA, otherwise returns *false*. 918 919Function : plat_has_unmanaged_dma_peripherals() 920~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 921 922:: 923 924 Argument : void 925 Return : bool 926 927This function returns *true* if platform uses peripherals whose DMA is not 928managed by an SMMU, otherwise returns *false*. 929 930Note - 931If the platform has peripherals that are not managed by the SMMU, then the 932platform should investigate such peripherals to determine whether they can 933be trusted, and such peripherals should be moved under "Non-host platforms" 934if they can be trusted. 935 936Function : plat_get_total_num_smmus() 937~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 938 939:: 940 941 Argument : void 942 Return : unsigned int 943 944This function returns the total number of SMMUs in the platform. 945 946Function : plat_enumerate_smmus() 947~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 948:: 949 950 951 Argument : void 952 Return : const uintptr_t *, size_t 953 954This function returns an array of SMMU addresses and the actual number of SMMUs 955reported by the platform. 956 957Function : plat_drtm_get_dma_prot_features() 958~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 959 960:: 961 962 Argument : void 963 Return : const plat_drtm_dma_prot_features_t* 964 965This function returns the address of plat_drtm_dma_prot_features_t structure 966containing the maximum number of protected regions and bitmap with the types 967of DMA protection supported by the platform. 968For more details see section 3.3 Table 6 of `DRTM`_ specification. 969 970Function : plat_drtm_dma_prot_get_max_table_bytes() 971~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 972 973:: 974 975 Argument : void 976 Return : uint64_t 977 978This function returns the maximum size of DMA protected regions table in 979bytes. 980 981Function : plat_drtm_get_tpm_features() 982~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 983 984:: 985 986 Argument : void 987 Return : const plat_drtm_tpm_features_t* 988 989This function returns the address of *plat_drtm_tpm_features_t* structure 990containing PCR usage schema, TPM-based hash, and firmware hash algorithm 991supported by the platform. 992 993Function : plat_drtm_get_min_size_normal_world_dce() 994~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 995 996:: 997 998 Argument : void 999 Return : uint64_t 1000 1001This function returns the size normal-world DCE of the platform. 1002 1003Function : plat_drtm_get_imp_def_dlme_region_size() 1004~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1005 1006:: 1007 1008 Argument : void 1009 Return : uint64_t 1010 1011This function returns the size of implementation defined DLME region 1012of the platform. 1013 1014Function : plat_drtm_get_tcb_hash_table_size() 1015~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1016 1017:: 1018 1019 Argument : void 1020 Return : uint64_t 1021 1022This function returns the size of TCB hash table of the platform. 1023 1024Function : plat_drtm_get_acpi_tables_region_size() 1025~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1026 1027:: 1028 1029 Argument : void 1030 Return : uint64_t 1031 1032This function returns the size of ACPI tables region of the platform. 1033 1034Function : plat_drtm_get_tcb_hash_features() 1035~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1036 1037:: 1038 1039 Argument : void 1040 Return : uint64_t 1041 1042This function returns the Maximum number of TCB hashes recorded by the 1043platform. 1044For more details see section 3.3 Table 6 of `DRTM`_ specification. 1045 1046Function : plat_drtm_get_dlme_img_auth_features() 1047~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1048 1049:: 1050 1051 Argument : void 1052 Return : uint64_t 1053 1054This function returns the DLME image authentication features. 1055For more details see section 3.3 Table 6 of `DRTM`_ specification. 1056 1057Function : plat_drtm_validate_ns_region() 1058~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1059 1060:: 1061 1062 Argument : uintptr_t, uintptr_t 1063 Return : int 1064 1065This function validates that given region is within the Non-Secure region 1066of DRAM. This function takes a region start address and size an input 1067arguments, and returns 0 on success and -1 on failure. 1068 1069Function : plat_set_drtm_error() 1070~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1071 1072:: 1073 1074 Argument : uint64_t 1075 Return : int 1076 1077This function writes a 64 bit error code received as input into 1078non-volatile storage and returns 0 on success and -1 on failure. 1079 1080Function : plat_get_drtm_error() 1081~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1082 1083:: 1084 1085 Argument : uint64_t* 1086 Return : int 1087 1088This function reads a 64 bit error code from the non-volatile storage 1089into the received address, and returns 0 on success and -1 on failure. 1090 1091Common mandatory function modifications 1092--------------------------------------- 1093 1094The following functions are mandatory functions which need to be implemented 1095by the platform port. 1096 1097Function : plat_my_core_pos() 1098~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1099 1100:: 1101 1102 Argument : void 1103 Return : unsigned int 1104 1105This function returns the index of the calling CPU which is used as a 1106CPU-specific linear index into blocks of memory (for example while allocating 1107per-CPU stacks). This function will be invoked very early in the 1108initialization sequence which mandates that this function should be 1109implemented in assembly and should not rely on the availability of a C 1110runtime environment. This function can clobber x0 - x8 and must preserve 1111x9 - x29. 1112 1113This function plays a crucial role in the power domain topology framework in 1114PSCI and details of this can be found in 1115:ref:`PSCI Power Domain Tree Structure`. 1116 1117Function : plat_core_pos_by_mpidr() 1118~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1119 1120:: 1121 1122 Argument : u_register_t 1123 Return : int 1124 1125This function validates the ``MPIDR`` of a CPU and converts it to an index, 1126which can be used as a CPU-specific linear index into blocks of memory. In 1127case the ``MPIDR`` is invalid, this function returns -1. This function will only 1128be invoked by BL31 after the power domain topology is initialized and can 1129utilize the C runtime environment. For further details about how TF-A 1130represents the power domain topology and how this relates to the linear CPU 1131index, please refer :ref:`PSCI Power Domain Tree Structure`. 1132 1133Function : plat_get_mbedtls_heap() [when TRUSTED_BOARD_BOOT == 1] 1134~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1135 1136:: 1137 1138 Arguments : void **heap_addr, size_t *heap_size 1139 Return : int 1140 1141This function is invoked during Mbed TLS library initialisation to get a heap, 1142by means of a starting address and a size. This heap will then be used 1143internally by the Mbed TLS library. Hence, each BL stage that utilises Mbed TLS 1144must be able to provide a heap to it. 1145 1146A helper function can be found in `drivers/auth/mbedtls/mbedtls_common.c` in 1147which a heap is statically reserved during compile time inside every image 1148(i.e. every BL stage) that utilises Mbed TLS. In this default implementation, 1149the function simply returns the address and size of this "pre-allocated" heap. 1150For a platform to use this default implementation, only a call to the helper 1151from inside plat_get_mbedtls_heap() body is enough and nothing else is needed. 1152 1153However, by writting their own implementation, platforms have the potential to 1154optimise memory usage. For example, on some Arm platforms, the Mbed TLS heap is 1155shared between BL1 and BL2 stages and, thus, the necessary space is not reserved 1156twice. 1157 1158On success the function should return 0 and a negative error code otherwise. 1159 1160Function : plat_get_enc_key_info() [when FW_ENC_STATUS == 0 or 1] 1161~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1162 1163:: 1164 1165 Arguments : enum fw_enc_status_t fw_enc_status, uint8_t *key, 1166 size_t *key_len, unsigned int *flags, const uint8_t *img_id, 1167 size_t img_id_len 1168 Return : int 1169 1170This function provides a symmetric key (either SSK or BSSK depending on 1171fw_enc_status) which is invoked during runtime decryption of encrypted 1172firmware images. `plat/common/plat_bl_common.c` provides a dummy weak 1173implementation for testing purposes which must be overridden by the platform 1174trying to implement a real world firmware encryption use-case. 1175 1176It also allows the platform to pass symmetric key identifier rather than 1177actual symmetric key which is useful in cases where the crypto backend provides 1178secure storage for the symmetric key. So in this case ``ENC_KEY_IS_IDENTIFIER`` 1179flag must be set in ``flags``. 1180 1181In addition to above a platform may also choose to provide an image specific 1182symmetric key/identifier using img_id. 1183 1184On success the function should return 0 and a negative error code otherwise. 1185 1186Note that this API depends on ``DECRYPTION_SUPPORT`` build flag. 1187 1188Function : plat_fwu_set_images_source() [when PSA_FWU_SUPPORT == 1] 1189~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1190 1191:: 1192 1193 Argument : const struct fwu_metadata *metadata 1194 Return : void 1195 1196This function is mandatory when PSA_FWU_SUPPORT is enabled. 1197It provides a means to retrieve image specification (offset in 1198non-volatile storage and length) of active/updated images using the passed 1199FWU metadata, and update I/O policies of active/updated images using retrieved 1200image specification information. 1201Further I/O layer operations such as I/O open, I/O read, etc. on these 1202images rely on this function call. 1203 1204In Arm platforms, this function is used to set an I/O policy of the FIP image, 1205container of all active/updated secure and non-secure images. 1206 1207Function : plat_fwu_set_metadata_image_source() [when PSA_FWU_SUPPORT == 1] 1208~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1209 1210:: 1211 1212 Argument : unsigned int image_id, uintptr_t *dev_handle, 1213 uintptr_t *image_spec 1214 Return : int 1215 1216This function is mandatory when PSA_FWU_SUPPORT is enabled. It is 1217responsible for setting up the platform I/O policy of the requested metadata 1218image (either FWU_METADATA_IMAGE_ID or BKUP_FWU_METADATA_IMAGE_ID) that will 1219be used to load this image from the platform's non-volatile storage. 1220 1221FWU metadata can not be always stored as a raw image in non-volatile storage 1222to define its image specification (offset in non-volatile storage and length) 1223statically in I/O policy. 1224For example, the FWU metadata image is stored as a partition inside the GUID 1225partition table image. Its specification is defined in the partition table 1226that needs to be parsed dynamically. 1227This function provides a means to retrieve such dynamic information to set 1228the I/O policy of the FWU metadata image. 1229Further I/O layer operations such as I/O open, I/O read, etc. on FWU metadata 1230image relies on this function call. 1231 1232It returns '0' on success, otherwise a negative error value on error. 1233Alongside, returns device handle and image specification from the I/O policy 1234of the requested FWU metadata image. 1235 1236Function : plat_fwu_get_boot_idx() [when PSA_FWU_SUPPORT == 1] 1237~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1238 1239:: 1240 1241 Argument : void 1242 Return : uint32_t 1243 1244This function is mandatory when PSA_FWU_SUPPORT is enabled. It provides the 1245means to retrieve the boot index value from the platform. The boot index is the 1246bank from which the platform has booted the firmware images. 1247 1248By default, the platform will read the metadata structure and try to boot from 1249the active bank. If the platform fails to boot from the active bank due to 1250reasons like an Authentication failure, or on crossing a set number of watchdog 1251resets while booting from the active bank, the platform can then switch to boot 1252from a different bank. This function then returns the bank that the platform 1253should boot its images from. 1254 1255Common optional modifications 1256----------------------------- 1257 1258The following are helper functions implemented by the firmware that perform 1259common platform-specific tasks. A platform may choose to override these 1260definitions. 1261 1262Function : plat_set_my_stack() 1263~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1264 1265:: 1266 1267 Argument : void 1268 Return : void 1269 1270This function sets the current stack pointer to the normal memory stack that 1271has been allocated for the current CPU. For BL images that only require a 1272stack for the primary CPU, the UP version of the function is used. The size 1273of the stack allocated to each CPU is specified by the platform defined 1274constant ``PLATFORM_STACK_SIZE``. 1275 1276Common implementations of this function for the UP and MP BL images are 1277provided in ``plat/common/aarch64/platform_up_stack.S`` and 1278``plat/common/aarch64/platform_mp_stack.S`` 1279 1280Function : plat_get_my_stack() 1281~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1282 1283:: 1284 1285 Argument : void 1286 Return : uintptr_t 1287 1288This function returns the base address of the normal memory stack that 1289has been allocated for the current CPU. For BL images that only require a 1290stack for the primary CPU, the UP version of the function is used. The size 1291of the stack allocated to each CPU is specified by the platform defined 1292constant ``PLATFORM_STACK_SIZE``. 1293 1294Common implementations of this function for the UP and MP BL images are 1295provided in ``plat/common/aarch64/platform_up_stack.S`` and 1296``plat/common/aarch64/platform_mp_stack.S`` 1297 1298Function : plat_report_exception() 1299~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1300 1301:: 1302 1303 Argument : unsigned int 1304 Return : void 1305 1306A platform may need to report various information about its status when an 1307exception is taken, for example the current exception level, the CPU security 1308state (secure/non-secure), the exception type, and so on. This function is 1309called in the following circumstances: 1310 1311- In BL1, whenever an exception is taken. 1312- In BL2, whenever an exception is taken. 1313 1314The default implementation doesn't do anything, to avoid making assumptions 1315about the way the platform displays its status information. 1316 1317For AArch64, this function receives the exception type as its argument. 1318Possible values for exceptions types are listed in the 1319``include/common/bl_common.h`` header file. Note that these constants are not 1320related to any architectural exception code; they are just a TF-A convention. 1321 1322For AArch32, this function receives the exception mode as its argument. 1323Possible values for exception modes are listed in the 1324``include/lib/aarch32/arch.h`` header file. 1325 1326Function : plat_reset_handler() 1327~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1328 1329:: 1330 1331 Argument : void 1332 Return : void 1333 1334A platform may need to do additional initialization after reset. This function 1335allows the platform to do the platform specific initializations. Platform 1336specific errata workarounds could also be implemented here. The API should 1337preserve the values of callee saved registers x19 to x29. 1338 1339The default implementation doesn't do anything. If a platform needs to override 1340the default implementation, refer to the :ref:`Firmware Design` for general 1341guidelines. 1342 1343Function : plat_disable_acp() 1344~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1345 1346:: 1347 1348 Argument : void 1349 Return : void 1350 1351This API allows a platform to disable the Accelerator Coherency Port (if 1352present) during a cluster power down sequence. The default weak implementation 1353doesn't do anything. Since this API is called during the power down sequence, 1354it has restrictions for stack usage and it can use the registers x0 - x17 as 1355scratch registers. It should preserve the value in x18 register as it is used 1356by the caller to store the return address. 1357 1358Function : plat_error_handler() 1359~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1360 1361:: 1362 1363 Argument : int 1364 Return : void 1365 1366This API is called when the generic code encounters an error situation from 1367which it cannot continue. It allows the platform to perform error reporting or 1368recovery actions (for example, reset the system). This function must not return. 1369 1370The parameter indicates the type of error using standard codes from ``errno.h``. 1371Possible errors reported by the generic code are: 1372 1373- ``-EAUTH``: a certificate or image could not be authenticated (when Trusted 1374 Board Boot is enabled) 1375- ``-ENOENT``: the requested image or certificate could not be found or an IO 1376 error was detected 1377- ``-ENOMEM``: resources exhausted. TF-A does not use dynamic memory, so this 1378 error is usually an indication of an incorrect array size 1379 1380The default implementation simply spins. 1381 1382Function : plat_panic_handler() 1383~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1384 1385:: 1386 1387 Argument : void 1388 Return : void 1389 1390This API is called when the generic code encounters an unexpected error 1391situation from which it cannot recover. This function must not return, 1392and must be implemented in assembly because it may be called before the C 1393environment is initialized. 1394 1395.. note:: 1396 The address from where it was called is stored in x30 (Link Register). 1397 The default implementation simply spins. 1398 1399Function : plat_get_bl_image_load_info() 1400~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1401 1402:: 1403 1404 Argument : void 1405 Return : bl_load_info_t * 1406 1407This function returns pointer to the list of images that the platform has 1408populated to load. This function is invoked in BL2 to load the 1409BL3xx images. 1410 1411Function : plat_get_next_bl_params() 1412~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1413 1414:: 1415 1416 Argument : void 1417 Return : bl_params_t * 1418 1419This function returns a pointer to the shared memory that the platform has 1420kept aside to pass TF-A related information that next BL image needs. This 1421function is invoked in BL2 to pass this information to the next BL 1422image. 1423 1424Function : plat_get_stack_protector_canary() 1425~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1426 1427:: 1428 1429 Argument : void 1430 Return : u_register_t 1431 1432This function returns a random value that is used to initialize the canary used 1433when the stack protector is enabled with ENABLE_STACK_PROTECTOR. A predictable 1434value will weaken the protection as the attacker could easily write the right 1435value as part of the attack most of the time. Therefore, it should return a 1436true random number. 1437 1438.. warning:: 1439 For the protection to be effective, the global data need to be placed at 1440 a lower address than the stack bases. Failure to do so would allow an 1441 attacker to overwrite the canary as part of the stack buffer overflow attack. 1442 1443Function : plat_flush_next_bl_params() 1444~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1445 1446:: 1447 1448 Argument : void 1449 Return : void 1450 1451This function flushes to main memory all the image params that are passed to 1452next image. This function is invoked in BL2 to flush this information 1453to the next BL image. 1454 1455Function : plat_log_get_prefix() 1456~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1457 1458:: 1459 1460 Argument : unsigned int 1461 Return : const char * 1462 1463This function defines the prefix string corresponding to the `log_level` to be 1464prepended to all the log output from TF-A. The `log_level` (argument) will 1465correspond to one of the standard log levels defined in debug.h. The platform 1466can override the common implementation to define a different prefix string for 1467the log output. The implementation should be robust to future changes that 1468increase the number of log levels. 1469 1470Function : plat_get_soc_version() 1471~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1472 1473:: 1474 1475 Argument : void 1476 Return : int32_t 1477 1478This function returns soc version which mainly consist of below fields 1479 1480:: 1481 1482 soc_version[30:24] = JEP-106 continuation code for the SiP 1483 soc_version[23:16] = JEP-106 identification code with parity bit for the SiP 1484 soc_version[15:0] = Implementation defined SoC ID 1485 1486Function : plat_get_soc_revision() 1487~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1488 1489:: 1490 1491 Argument : void 1492 Return : int32_t 1493 1494This function returns soc revision in below format 1495 1496:: 1497 1498 soc_revision[0:30] = SOC revision of specific SOC 1499 1500Function : plat_get_soc_name() 1501~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1502 1503:: 1504 1505 Argument : char ** 1506 Return : int32_t 1507 1508The plat_get_soc_name() function allows a platform to expose the SoC name to 1509the firmware. It takes a pointer to a character pointer as an argument, which 1510must be set to point to a static, null-terminated SoC name string. The string 1511must be encoded in UTF-8 and should use only printable ASCII characters for 1512compatibility. It must not exceed 136 bytes, including the null terminator. On 1513success, the function returns SMC_ARCH_CALL_SUCCESS. If the platform does not 1514support SoC name retrieval, it returns SMC_ARCH_CALL_NOT_SUPPORTED. This API 1515allows platforms to support SoC name queries via SMCCC_ARCH_SOC_ID. 1516 1517Function : plat_is_smccc_feature_available() 1518~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1519 1520:: 1521 1522 Argument : u_register_t 1523 Return : int32_t 1524 1525This function returns SMC_ARCH_CALL_SUCCESS if the platform supports 1526the SMCCC function specified in the argument; otherwise returns 1527SMC_ARCH_CALL_NOT_SUPPORTED. 1528 1529Function : plat_can_cmo() 1530~~~~~~~~~~~~~~~~~~~~~~~~~ 1531 1532:: 1533 1534 Argument : void 1535 Return : uint64_t 1536 1537When CONDITIONAL_CMO flag is enabled: 1538 1539- This function indicates whether cache management operations should be 1540 performed. It returns 0 if CMOs should be skipped and non-zero 1541 otherwise. 1542- The function must not clobber x1, x2 and x3. It's also not safe to rely on 1543 stack. Otherwise obey AAPCS. 1544 1545Struct: plat_try_images_ops [optional] 1546~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1547 1548This optional structure holds platform hooks for alternative images load. 1549It has to be defined in platform code and registered by calling 1550plat_setup_try_img_ops() function, passing it the address of the 1551plat_try_images_ops struct. 1552 1553Function : plat_setup_try_img_ops [optional] 1554............................................ 1555 1556:: 1557 1558 Argument : const struct plat_try_images_ops * 1559 Return : void 1560 1561This optional function is called to register platform try images ops, given 1562as argument. 1563 1564Function : plat_try_images_ops.next_instance [optional] 1565....................................................... 1566 1567:: 1568 1569 Argument : unsigned int image_id 1570 Return : int 1571 1572This optional function tries to load images from alternative places. 1573In case PSA FWU is not used, it can be any instance or media. If PSA FWU is 1574used, it is mandatory that the backup image is on the same media. 1575This is required for MTD devices like NAND. 1576The argument is the ID of the image for which we are looking for an alternative 1577place. It returns 0 in case of success and a negative errno value otherwise. 1578 1579Modifications specific to a Boot Loader stage 1580--------------------------------------------- 1581 1582Boot Loader Stage 1 (BL1) 1583------------------------- 1584 1585BL1 implements the reset vector where execution starts from after a cold or 1586warm boot. For each CPU, BL1 is responsible for the following tasks: 1587 1588#. Handling the reset as described in section 2.2 1589 1590#. In the case of a cold boot and the CPU being the primary CPU, ensuring that 1591 only this CPU executes the remaining BL1 code, including loading and passing 1592 control to the BL2 stage. 1593 1594#. Identifying and starting the Firmware Update process (if required). 1595 1596#. Loading the BL2 image from non-volatile storage into secure memory at the 1597 address specified by the platform defined constant ``BL2_BASE``. 1598 1599#. Populating a ``meminfo`` structure with the following information in memory, 1600 accessible by BL2 immediately upon entry. 1601 1602 :: 1603 1604 meminfo.total_base = Base address of secure RAM visible to BL2 1605 meminfo.total_size = Size of secure RAM visible to BL2 1606 1607 By default, BL1 places this ``meminfo`` structure at the end of secure 1608 memory visible to BL2. 1609 1610 It is possible for the platform to decide where it wants to place the 1611 ``meminfo`` structure for BL2 or restrict the amount of memory visible to 1612 BL2 by overriding the weak default implementation of 1613 ``bl1_plat_handle_post_image_load`` API. 1614 1615The following functions need to be implemented by the platform port to enable 1616BL1 to perform the above tasks. 1617 1618Function : bl1_early_platform_setup() [mandatory] 1619~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1620 1621:: 1622 1623 Argument : void 1624 Return : void 1625 1626This function executes with the MMU and data caches disabled. It is only called 1627by the primary CPU. 1628 1629On Arm standard platforms, this function: 1630 1631- Enables a secure instance of SP805 to act as the Trusted Watchdog. 1632 1633- Initializes a UART (PL011 console), which enables access to the ``printf`` 1634 family of functions in BL1. 1635 1636- Enables issuing of snoop and DVM (Distributed Virtual Memory) requests to 1637 the CCI slave interface corresponding to the cluster that includes the 1638 primary CPU. 1639 1640Function : bl1_plat_arch_setup() [mandatory] 1641~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1642 1643:: 1644 1645 Argument : void 1646 Return : void 1647 1648This function performs any platform-specific and architectural setup that the 1649platform requires. Platform-specific setup might include configuration of 1650memory controllers and the interconnect. 1651 1652In Arm standard platforms, this function enables the MMU. 1653 1654This function helps fulfill requirement 2 above. 1655 1656Function : bl1_platform_setup() [mandatory] 1657~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1658 1659:: 1660 1661 Argument : void 1662 Return : void 1663 1664This function executes with the MMU and data caches enabled. It is responsible 1665for performing any remaining platform-specific setup that can occur after the 1666MMU and data cache have been enabled. 1667 1668In Arm standard platforms, this function initializes the storage abstraction 1669layer used to load the next bootloader image. 1670 1671This function helps fulfill requirement 4 above. 1672 1673Function : bl1_plat_sec_mem_layout() [mandatory] 1674~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1675 1676:: 1677 1678 Argument : void 1679 Return : meminfo * 1680 1681This function should only be called on the cold boot path. It executes with the 1682MMU and data caches enabled. The pointer returned by this function must point to 1683a ``meminfo`` structure containing the extents and availability of secure RAM for 1684the BL1 stage. 1685 1686:: 1687 1688 meminfo.total_base = Base address of secure RAM visible to BL1 1689 meminfo.total_size = Size of secure RAM visible to BL1 1690 1691This information is used by BL1 to load the BL2 image in secure RAM. BL1 also 1692populates a similar structure to tell BL2 the extents of memory available for 1693its own use. 1694 1695This function helps fulfill requirements 4 and 5 above. 1696 1697Function : bl1_plat_prepare_exit() [optional] 1698~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1699 1700:: 1701 1702 Argument : entry_point_info_t * 1703 Return : void 1704 1705This function is called prior to exiting BL1 in response to the 1706``BL1_SMC_RUN_IMAGE`` SMC request raised by BL2. It should be used to perform 1707platform specific clean up or bookkeeping operations before transferring 1708control to the next image. It receives the address of the ``entry_point_info_t`` 1709structure passed from BL2. This function runs with MMU disabled. 1710 1711Function : bl1_plat_set_ep_info() [optional] 1712~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1713 1714:: 1715 1716 Argument : unsigned int image_id, entry_point_info_t *ep_info 1717 Return : void 1718 1719This function allows platforms to override ``ep_info`` for the given ``image_id``. 1720 1721The default implementation just returns. 1722 1723Function : bl1_plat_get_next_image_id() [optional] 1724~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1725 1726:: 1727 1728 Argument : void 1729 Return : unsigned int 1730 1731This and the following function must be overridden to enable the FWU feature. 1732 1733BL1 calls this function after platform setup to identify the next image to be 1734loaded and executed. If the platform returns ``BL2_IMAGE_ID`` then BL1 proceeds 1735with the normal boot sequence, which loads and executes BL2. If the platform 1736returns a different image id, BL1 assumes that Firmware Update is required. 1737 1738The default implementation always returns ``BL2_IMAGE_ID``. The Arm development 1739platforms override this function to detect if firmware update is required, and 1740if so, return the first image in the firmware update process. 1741 1742Function : bl1_plat_get_image_desc() [optional] 1743~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1744 1745:: 1746 1747 Argument : unsigned int image_id 1748 Return : image_desc_t * 1749 1750BL1 calls this function to get the image descriptor information ``image_desc_t`` 1751for the provided ``image_id`` from the platform. 1752 1753The default implementation always returns a common BL2 image descriptor. Arm 1754standard platforms return an image descriptor corresponding to BL2 or one of 1755the firmware update images defined in the Trusted Board Boot Requirements 1756specification. 1757 1758Function : bl1_plat_handle_pre_image_load() [optional] 1759~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1760 1761:: 1762 1763 Argument : unsigned int image_id 1764 Return : int 1765 1766This function can be used by the platforms to update/use image information 1767corresponding to ``image_id``. This function is invoked in BL1, both in cold 1768boot and FWU code path, before loading the image. 1769 1770Function : bl1_plat_calc_bl2_layout() [optional] 1771~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1772 1773:: 1774 1775 Argument : const meminfo_t *bl1_mem_layout, meminfo_t *bl2_mem_layout 1776 Return : void 1777 1778This utility function calculates the memory layout of BL2, representing it in a 1779`meminfo_t` structure. The default implementation derives this layout from the 1780positioning of BL1’s RW data at the top of the memory layout. 1781 1782Function : bl1_plat_handle_post_image_load() [optional] 1783~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1784 1785:: 1786 1787 Argument : unsigned int image_id 1788 Return : int 1789 1790This function can be used by the platforms to update/use image information 1791corresponding to ``image_id``. This function is invoked in BL1, both in cold 1792boot and FWU code path, after loading and authenticating the image. 1793 1794The default weak implementation of this function calculates the amount of 1795Trusted SRAM that can be used by BL2 and allocates a ``meminfo_t`` 1796structure at the beginning of this free memory and populates it. The address 1797of ``meminfo_t`` structure is updated in ``arg1`` of the entrypoint 1798information to BL2. 1799 1800Function : bl1_plat_fwu_done() [optional] 1801~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1802 1803:: 1804 1805 Argument : unsigned int image_id, uintptr_t image_src, 1806 unsigned int image_size 1807 Return : void 1808 1809BL1 calls this function when the FWU process is complete. It must not return. 1810The platform may override this function to take platform specific action, for 1811example to initiate the normal boot flow. 1812 1813The default implementation spins forever. 1814 1815Function : bl1_plat_mem_check() [mandatory] 1816~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1817 1818:: 1819 1820 Argument : uintptr_t mem_base, unsigned int mem_size, 1821 unsigned int flags 1822 Return : int 1823 1824BL1 calls this function while handling FWU related SMCs, more specifically when 1825copying or authenticating an image. Its responsibility is to ensure that the 1826region of memory identified by ``mem_base`` and ``mem_size`` is mapped in BL1, and 1827that this memory corresponds to either a secure or non-secure memory region as 1828indicated by the security state of the ``flags`` argument. 1829 1830This function can safely assume that the value resulting from the addition of 1831``mem_base`` and ``mem_size`` fits into a ``uintptr_t`` type variable and does not 1832overflow. 1833 1834This function must return 0 on success, a non-null error code otherwise. 1835 1836The default implementation of this function asserts therefore platforms must 1837override it when using the FWU feature. 1838 1839Boot Loader Stage 2 (BL2) 1840------------------------- 1841 1842The BL2 stage is executed only by the primary CPU, which is determined in BL1 1843using the ``platform_is_primary_cpu()`` function. BL1 passed control to BL2 at 1844``BL2_BASE``. BL2 executes in Secure EL1 and and invokes 1845``plat_get_bl_image_load_info()`` to retrieve the list of images to load from 1846non-volatile storage to secure/non-secure RAM. After all the images are loaded 1847then BL2 invokes ``plat_get_next_bl_params()`` to get the list of executable 1848images to be passed to the next BL image. 1849 1850The following functions must be implemented by the platform port to enable BL2 1851to perform the above tasks. 1852 1853Function : bl2_early_platform_setup2() [mandatory] 1854~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1855 1856:: 1857 1858 Argument : u_register_t, u_register_t, u_register_t, u_register_t 1859 Return : void 1860 1861This function executes with the MMU and data caches disabled. It is only called 1862by the primary CPU. The 4 arguments are passed by BL1 to BL2 and these arguments 1863are platform specific. 1864 1865On Arm standard platforms, the arguments received are : 1866 1867 arg0 - Points to load address of FW_CONFIG 1868 1869 arg1 - ``meminfo`` structure populated by BL1. The platform copies 1870 the contents of ``meminfo`` as it may be subsequently overwritten by BL2. 1871 1872On Arm standard platforms, this function also: 1873 1874- Initializes a UART (PL011 console), which enables access to the ``printf`` 1875 family of functions in BL2. 1876 1877- Initializes the storage abstraction layer used to load further bootloader 1878 images. It is necessary to do this early on platforms with a SCP_BL2 image, 1879 since the later ``bl2_platform_setup`` must be done after SCP_BL2 is loaded. 1880 1881Function : bl2_plat_arch_setup() [mandatory] 1882~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1883 1884:: 1885 1886 Argument : void 1887 Return : void 1888 1889This function executes with the MMU and data caches disabled. It is only called 1890by the primary CPU. 1891 1892The purpose of this function is to perform any architectural initialization 1893that varies across platforms. 1894 1895On Arm standard platforms, this function enables the MMU. 1896 1897Function : bl2_platform_setup() [mandatory] 1898~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1899 1900:: 1901 1902 Argument : void 1903 Return : void 1904 1905This function may execute with the MMU and data caches enabled if the platform 1906port does the necessary initialization in ``bl2_plat_arch_setup()``. It is only 1907called by the primary CPU. 1908 1909The purpose of this function is to perform any platform initialization 1910specific to BL2. 1911 1912In Arm standard platforms, this function performs security setup, including 1913configuration of the TrustZone controller to allow non-secure masters access 1914to most of DRAM. Part of DRAM is reserved for secure world use. 1915 1916Function : bl2_plat_handle_pre_image_load() [optional] 1917~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1918 1919:: 1920 1921 Argument : unsigned int 1922 Return : int 1923 1924This function can be used by the platforms to update/use image information 1925for given ``image_id``. This function is currently invoked in BL2 before 1926loading each image. 1927 1928Function : bl2_plat_handle_post_image_load() [optional] 1929~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1930 1931:: 1932 1933 Argument : unsigned int 1934 Return : int 1935 1936This function can be used by the platforms to update/use image information 1937for given ``image_id``. This function is currently invoked in BL2 after 1938loading each image. 1939 1940Function : bl2_plat_preload_setup [optional] 1941~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1942 1943:: 1944 1945 Argument : void 1946 Return : void 1947 1948This optional function performs any BL2 platform initialization 1949required before image loading, that is not done later in 1950bl2_platform_setup(). 1951 1952Boot Loader Stage 2 (BL2) at EL3 1953-------------------------------- 1954 1955When the platform has a non-TF-A Boot ROM it is desirable to jump 1956directly to BL2 instead of TF-A BL1. In this case BL2 is expected to 1957execute at EL3 instead of executing at EL1. Refer to the :ref:`Firmware Design` 1958document for more information. 1959 1960All mandatory functions of BL2 must be implemented, except the functions 1961bl2_early_platform_setup and bl2_el3_plat_arch_setup, because 1962their work is done now by bl2_el3_early_platform_setup and 1963bl2_el3_plat_arch_setup. These functions should generally implement 1964the bl1_plat_xxx() and bl2_plat_xxx() functionality combined. 1965 1966 1967Function : bl2_el3_early_platform_setup() [mandatory] 1968~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1969 1970:: 1971 1972 Argument : u_register_t, u_register_t, u_register_t, u_register_t 1973 Return : void 1974 1975This function executes with the MMU and data caches disabled. It is only called 1976by the primary CPU. This function receives four parameters which can be used 1977by the platform to pass any needed information from the Boot ROM to BL2. 1978 1979On Arm standard platforms, this function does the following: 1980 1981- Initializes a UART (PL011 console), which enables access to the ``printf`` 1982 family of functions in BL2. 1983 1984- Initializes the storage abstraction layer used to load further bootloader 1985 images. It is necessary to do this early on platforms with a SCP_BL2 image, 1986 since the later ``bl2_platform_setup`` must be done after SCP_BL2 is loaded. 1987 1988- Initializes the private variables that define the memory layout used. 1989 1990Function : bl2_el3_plat_arch_setup() [mandatory] 1991~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1992 1993:: 1994 1995 Argument : void 1996 Return : void 1997 1998This function executes with the MMU and data caches disabled. It is only called 1999by the primary CPU. 2000 2001The purpose of this function is to perform any architectural initialization 2002that varies across platforms. 2003 2004On Arm standard platforms, this function enables the MMU. 2005 2006Function : bl2_el3_plat_prepare_exit() [optional] 2007~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 2008 2009:: 2010 2011 Argument : void 2012 Return : void 2013 2014This function is called prior to exiting BL2 and run the next image. 2015It should be used to perform platform specific clean up or bookkeeping 2016operations before transferring control to the next image. This function 2017runs with MMU disabled. 2018 2019FWU Boot Loader Stage 2 (BL2U) 2020------------------------------ 2021 2022The AP Firmware Updater Configuration, BL2U, is an optional part of the FWU 2023process and is executed only by the primary CPU. BL1 passes control to BL2U at 2024``BL2U_BASE``. BL2U executes in Secure-EL1 and is responsible for: 2025 2026#. (Optional) Transferring the optional SCP_BL2U binary image from AP secure 2027 memory to SCP RAM. BL2U uses the SCP_BL2U ``image_info`` passed by BL1. 2028 ``SCP_BL2U_BASE`` defines the address in AP secure memory where SCP_BL2U 2029 should be copied from. Subsequent handling of the SCP_BL2U image is 2030 implemented by the platform specific ``bl2u_plat_handle_scp_bl2u()`` function. 2031 If ``SCP_BL2U_BASE`` is not defined then this step is not performed. 2032 2033#. Any platform specific setup required to perform the FWU process. For 2034 example, Arm standard platforms initialize the TZC controller so that the 2035 normal world can access DDR memory. 2036 2037The following functions must be implemented by the platform port to enable 2038BL2U to perform the tasks mentioned above. 2039 2040Function : bl2u_early_platform_setup() [mandatory] 2041~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 2042 2043:: 2044 2045 Argument : meminfo *mem_info, void *plat_info 2046 Return : void 2047 2048This function executes with the MMU and data caches disabled. It is only 2049called by the primary CPU. The arguments to this function is the address 2050of the ``meminfo`` structure and platform specific info provided by BL1. 2051 2052The platform may copy the contents of the ``mem_info`` and ``plat_info`` into 2053private storage as the original memory may be subsequently overwritten by BL2U. 2054 2055On Arm CSS platforms ``plat_info`` is interpreted as an ``image_info_t`` structure, 2056to extract SCP_BL2U image information, which is then copied into a private 2057variable. 2058 2059Function : bl2u_plat_arch_setup() [mandatory] 2060~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 2061 2062:: 2063 2064 Argument : void 2065 Return : void 2066 2067This function executes with the MMU and data caches disabled. It is only 2068called by the primary CPU. 2069 2070The purpose of this function is to perform any architectural initialization 2071that varies across platforms, for example enabling the MMU (since the memory 2072map differs across platforms). 2073 2074Function : bl2u_platform_setup() [mandatory] 2075~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 2076 2077:: 2078 2079 Argument : void 2080 Return : void 2081 2082This function may execute with the MMU and data caches enabled if the platform 2083port does the necessary initialization in ``bl2u_plat_arch_setup()``. It is only 2084called by the primary CPU. 2085 2086The purpose of this function is to perform any platform initialization 2087specific to BL2U. 2088 2089In Arm standard platforms, this function performs security setup, including 2090configuration of the TrustZone controller to allow non-secure masters access 2091to most of DRAM. Part of DRAM is reserved for secure world use. 2092 2093Function : bl2u_plat_handle_scp_bl2u() [optional] 2094~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 2095 2096:: 2097 2098 Argument : void 2099 Return : int 2100 2101This function is used to perform any platform-specific actions required to 2102handle the SCP firmware. Typically it transfers the image into SCP memory using 2103a platform-specific protocol and waits until SCP executes it and signals to the 2104Application Processor (AP) for BL2U execution to continue. 2105 2106This function returns 0 on success, a negative error code otherwise. 2107This function is included if SCP_BL2U_BASE is defined. 2108 2109Boot Loader Stage 3-1 (BL31) 2110---------------------------- 2111 2112During cold boot, the BL31 stage is executed only by the primary CPU. This is 2113determined in BL1 using the ``platform_is_primary_cpu()`` function. BL1 passes 2114control to BL31 at ``BL31_BASE``. During warm boot, BL31 is executed by all 2115CPUs. BL31 executes at EL3 and is responsible for: 2116 2117#. Re-initializing all architectural and platform state. Although BL1 performs 2118 some of this initialization, BL31 remains resident in EL3 and must ensure 2119 that EL3 architectural and platform state is completely initialized. It 2120 should make no assumptions about the system state when it receives control. 2121 2122#. Passing control to a normal world BL image, pre-loaded at a platform- 2123 specific address by BL2. On ARM platforms, BL31 uses the ``bl_params`` list 2124 populated by BL2 in memory to do this. 2125 2126#. Providing runtime firmware services. Currently, BL31 only implements a 2127 subset of the Power State Coordination Interface (PSCI) API as a runtime 2128 service. See :ref:`psci_in_bl31` below for details of porting the PSCI 2129 implementation. 2130 2131#. Optionally passing control to the BL32 image, pre-loaded at a platform- 2132 specific address by BL2. BL31 exports a set of APIs that allow runtime 2133 services to specify the security state in which the next image should be 2134 executed and run the corresponding image. On ARM platforms, BL31 uses the 2135 ``bl_params`` list populated by BL2 in memory to do this. 2136 2137If BL31 is a reset vector, It also needs to handle the reset as specified in 2138section 2.2 before the tasks described above. 2139 2140The following functions must be implemented by the platform port to enable BL31 2141to perform the above tasks. 2142 2143Function : bl31_early_platform_setup2() [mandatory] 2144~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 2145 2146:: 2147 2148 Argument : u_register_t, u_register_t, u_register_t, u_register_t 2149 Return : void 2150 2151This function executes with the MMU and data caches disabled. It is only called 2152by the primary CPU. BL2 can pass 4 arguments to BL31 and these arguments are 2153platform specific. 2154 2155In Arm standard platforms, the arguments received are : 2156 2157 arg0 - The pointer to the head of `bl_params_t` list 2158 which is list of executable images following BL31, 2159 2160 arg1 - Points to load address of SOC_FW_CONFIG if present 2161 except in case of Arm FVP and Juno platform. 2162 2163 In case of Arm FVP and Juno platform, points to load address 2164 of FW_CONFIG. 2165 2166 arg2 - Points to load address of HW_CONFIG if present 2167 2168 arg3 - A special value to verify platform parameters from BL2 to BL31. Not 2169 used in release builds. 2170 2171The function runs through the `bl_param_t` list and extracts the entry point 2172information for BL32 and BL33. It also performs the following: 2173 2174- Initialize a UART (PL011 console), which enables access to the ``printf`` 2175 family of functions in BL31. 2176 2177- Enable issuing of snoop and DVM (Distributed Virtual Memory) requests to the 2178 CCI slave interface corresponding to the cluster that includes the primary 2179 CPU. 2180 2181Function : bl31_plat_arch_setup() [mandatory] 2182~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 2183 2184:: 2185 2186 Argument : void 2187 Return : void 2188 2189This function executes with the MMU and data caches disabled. It is only called 2190by the primary CPU. 2191 2192The purpose of this function is to perform any architectural initialization 2193that varies across platforms. 2194 2195On Arm standard platforms, this function enables the MMU. 2196 2197Function : bl31_platform_setup() [mandatory] 2198~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 2199 2200:: 2201 2202 Argument : void 2203 Return : void 2204 2205This function may execute with the MMU and data caches enabled if the platform 2206port does the necessary initialization in ``bl31_plat_arch_setup()``. It is only 2207called by the primary CPU. 2208 2209The purpose of this function is to complete platform initialization so that both 2210BL31 runtime services and normal world software can function correctly. 2211 2212On Arm standard platforms, this function does the following: 2213 2214- Initialize the generic interrupt controller. 2215 2216 Depending on the GIC driver selected by the platform, the appropriate GICv2 2217 or GICv3 initialization will be done, which mainly consists of: 2218 2219 - Enable secure interrupts in the GIC CPU interface. 2220 - Disable the legacy interrupt bypass mechanism. 2221 - Configure the priority mask register to allow interrupts of all priorities 2222 to be signaled to the CPU interface. 2223 - Mark SGIs 8-15 and the other secure interrupts on the platform as secure. 2224 - Target all secure SPIs to CPU0. 2225 - Enable these secure interrupts in the GIC distributor. 2226 - Configure all other interrupts as non-secure. 2227 - Enable signaling of secure interrupts in the GIC distributor. 2228 2229- Enable system-level implementation of the generic timer counter through the 2230 memory mapped interface. 2231 2232- Grant access to the system counter timer module 2233 2234- Initialize the power controller device. 2235 2236 In particular, initialise the locks that prevent concurrent accesses to the 2237 power controller device. 2238 2239Function : bl31_plat_runtime_setup() [optional] 2240~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 2241 2242:: 2243 2244 Argument : void 2245 Return : void 2246 2247The purpose of this function is to allow the platform to perform any BL31 runtime 2248setup just prior to BL31 exit during cold boot. The default weak implementation 2249of this function is empty. Any platform that needs to perform additional runtime 2250setup, before BL31 exits, will need to override this function. 2251 2252Function : bl31_plat_get_next_image_ep_info() [mandatory] 2253~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 2254 2255:: 2256 2257 Argument : uint32_t 2258 Return : entry_point_info * 2259 2260This function may execute with the MMU and data caches enabled if the platform 2261port does the necessary initializations in ``bl31_plat_arch_setup()``. 2262 2263This function is called by ``bl31_main()`` to retrieve information provided by 2264BL2 for the next image in the security state specified by the argument. BL31 2265uses this information to pass control to that image in the specified security 2266state. This function must return a pointer to the ``entry_point_info`` structure 2267(that was copied during ``bl31_early_platform_setup()``) if the image exists. It 2268should return NULL otherwise. 2269 2270Function : plat_rmmd_get_cca_attest_token() [mandatory when ENABLE_RME == 1] 2271~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 2272 2273:: 2274 2275 Argument : uintptr_t, size_t *, uintptr_t, size_t, size_t * 2276 Return : int 2277 2278This function returns the Platform attestation token. If the full token does 2279not fit in the buffer, the function will return a hunk of the token and 2280indicate how many bytes were copied and how many are pending. Multiple calls 2281to this function may be needed to retrieve the entire token. 2282 2283The parameters of the function are: 2284 2285 arg0 - A pointer to the buffer where the Platform token should be copied by 2286 this function. If the platform token does not completely fit in the 2287 buffer, the function may return a piece of the token only. 2288 2289 arg1 - Contains the size (in bytes) of the buffer passed in arg0. In 2290 addition, this parameter is used by the function to return the size 2291 of the platform token length hunk copied to the buffer. 2292 2293 arg2 - A pointer to the buffer where the challenge object is stored. 2294 2295 arg3 - The length of the challenge object in bytes. Possible values are 32, 2296 48 and 64. This argument must be zero for subsequent calls to 2297 retrieve the remaining hunks of the token. 2298 2299 arg4 - Returns the remaining length of the token (in bytes) that is yet to 2300 be returned in further calls. 2301 2302The function returns 0 on success, -EINVAL on failure and -EAGAIN if the 2303resource associated with the platform token retrieval is busy. 2304 2305Function : plat_rmmd_get_cca_realm_attest_key() [mandatory when ENABLE_RME == 1] 2306~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 2307 2308:: 2309 2310 Argument : uintptr_t, size_t *, unsigned int 2311 Return : int 2312 2313This function returns the delegated realm attestation key which will be used to 2314sign Realm attestation token. The API currently only supports P-384 ECC curve 2315key. 2316 2317The parameters of the function are: 2318 2319 arg0 - A pointer to the buffer where the attestation key should be copied 2320 by this function. The buffer must be big enough to hold the 2321 attestation key. 2322 2323 arg1 - Contains the size (in bytes) of the buffer passed in arg0. The 2324 function returns the attestation key length in this parameter. 2325 2326 arg2 - The type of the elliptic curve to which the requested attestation key 2327 belongs. 2328 2329The function returns 0 on success, -EINVAL on failure. 2330 2331Function : plat_rmmd_get_el3_rmm_shared_mem() [when ENABLE_RME == 1] 2332~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 2333 2334:: 2335 2336 Argument : uintptr_t * 2337 Return : size_t 2338 2339This function returns the size of the shared area between EL3 and RMM (or 0 on 2340failure). A pointer to the shared area (or a NULL pointer on failure) is stored 2341in the pointer passed as argument. 2342 2343Function : plat_rmmd_load_manifest() [when ENABLE_RME == 1] 2344~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 2345 2346:: 2347 2348 Arguments : rmm_manifest_t *manifest 2349 Return : int 2350 2351When ENABLE_RME is enabled, this function populates a boot manifest for the 2352RMM image and stores it in the area specified by manifest. 2353 2354When ENABLE_RME is disabled, this function is not used. 2355 2356Function : plat_rmm_mecid_key_update() [when ENABLE_RME == 1] 2357~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 2358 2359:: 2360 2361 Argument : uint16_t 2362 Return : int 2363 2364This function is invoked by BL31's RMMD when there is a request from the RMM 2365monitor to update the tweak for the encryption key associated to a MECID. 2366 2367The first parameter (``uint16_t mecid``) contains the MECID for which the 2368encryption key is to be updated. 2369 2370Return value is 0 upon success and -EFAULT otherwise. 2371 2372This function needs to be implemented by a platform if it enables RME. 2373 2374Function : plat_rmmd_el3_token_sign_push_req() [mandatory when RMMD_ENABLE_EL3_TOKEN_SIGN == 1] 2375~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 2376 2377:: 2378 2379 Arguments : const struct el3_token_sign_request *req 2380 Return : int 2381 2382Queue realm attestation token signing request from the RMM in EL3. The interface between 2383the RMM and EL3 is modeled as a queue but the underlying implementation may be different, 2384so long as the semantics of queuing and the error codes are used as defined below. 2385 2386See :ref:`el3_token_sign_request_struct` for definition of the request structure. 2387 2388Optional interface from the RMM-EL3 interface v0.4 onwards. 2389 2390The parameters of the functions are: 2391 arg0: Pointer to the token sign request to be pushed to EL3. 2392 The structure must be located in the RMM-EL3 shared 2393 memory buffer and must be locked before use. 2394 2395Return codes: 2396 - E_RMM_OK On Success. 2397 - E_RMM_INVAL If the arguments are invalid. 2398 - E_RMM_AGAIN Indicates that the request was not queued since the 2399 queue in EL3 is full. This may also be returned for any reason 2400 or situation in the system, that prevents accepting the request 2401 from the RMM. 2402 - E_RMM_UNK If the SMC is not implemented or if interface 2403 version is < 0.4. 2404 2405Function : plat_rmmd_el3_token_sign_pull_resp() [mandatory when RMMD_ENABLE_EL3_TOKEN_SIGN == 1] 2406~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 2407 2408:: 2409 2410 Arguments : struct el3_token_sign_response *resp 2411 Return : int 2412 2413Populate the attestation signing response in the ``resp`` parameter. The interface between 2414the RMM and EL3 is modeled as a queue for responses but the underlying implementation may 2415be different, so long as the semantics of queuing and the error codes are used as defined 2416below. 2417 2418See :ref:`el3_token_sign_response_struct` for definition of the response structure. 2419 2420Optional interface from the RMM-EL3 interface v0.4 onwards. 2421 2422The parameters of the functions are: 2423 resp: Pointer to the token sign response to get from EL3. 2424 The structure must be located in the RMM-EL3 shared 2425 memory buffer and must be locked before use. 2426 2427Return: 2428 - E_RMM_OK On Success. 2429 - E_RMM_INVAL If the arguments are invalid. 2430 - E_RMM_AGAIN Indicates that a response is not ready yet. 2431 - E_RMM_UNK If the SMC is not implemented or if interface 2432 version is < 0.4. 2433 2434Function : plat_rmmd_el3_token_sign_get_rak_pub() [mandatory when RMMD_ENABLE_EL3_TOKEN_SIGN == 1] 2435~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 2436 2437:: 2438 2439 Argument : uintptr_t, size_t *, unsigned int 2440 Return : int 2441 2442This function returns the public portion of the realm attestation key which will be used to 2443sign Realm attestation token. Typically, with delegated attestation, the private key is 2444returned, however, there may be platforms where the private key bits are better protected 2445in a platform specific manner such that the private key is not exposed. In such cases, 2446the RMM will only cache the public key and forward any requests such as signing, that 2447uses the private key to EL3. The API currently only supports P-384 ECC curve key. 2448 2449This is an optional interface from the RMM-EL3 interface v0.4 onwards. 2450 2451The parameters of the function are: 2452 2453 arg0 - A pointer to the buffer where the public key should be copied 2454 by this function. The buffer must be big enough to hold the 2455 attestation key. 2456 2457 arg1 - Contains the size (in bytes) of the buffer passed in arg0. The 2458 function returns the attestation key length in this parameter. 2459 2460 arg2 - The type of the elliptic curve to which the requested attestation key 2461 belongs. 2462 2463The function returns E_RMM_OK on success, RMM_E_INVAL if arguments are invalid and 2464E_RMM_UNK if the SMC is not implemented or if interface version is < 0.4. 2465 2466Function : plat_rmmd_el3_ide_key_program() [mandatory when RMMD_ENABLE_IDE_KEY_PROG == 1] 2467~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 2468 2469:: 2470 2471 Argument : uint64_t, uint64_t, uint64_t, struct rp_ide_key_info_t *, uint64_t, uint64_t 2472 Return : int 2473 2474This function sets the key/IV info for an IDE stream at the Root port. The key is 256 bits 2475and IV is 96 bits. The caller calls this SMC to program this key to the Rx and Tx ports 2476and for each substream corresponding to a single keyset. The platform should validate 2477the arguments `Ecam address` and `Rootport ID` before acting on it. The arguments `request ID` 2478and `cookie` are to be ignored for blocking mode and are pass-through to the response for 2479non-blocking mode. 2480 2481The platform needs to ensure proper exclusives are in place when accessed from multiple CPUs. 2482Depending on the expected latency for IDE-KM interface, the platform should choose blocking 2483or non-blocking semantics. More details about IDE Setup flow can be found 2484in this `RFC <https://github.com/TF-RMM/tf-rmm/wiki/RFC:-EL3-RMM-IDE-KM-Interface>`_. 2485 2486The parameters of the function are: 2487 2488 arg0 - The ecam address, to access and configure PCI devices in a system. 2489 2490 arg1 - The rootport ID used to identify the PCIe rootport of a connected device. 2491 2492 arg2 - The IDE stream info associated with a physical device, this parameter packs the 2493 the keyset, direction, substream and stream ID info. 2494 2495 arg3 - Structure with key and IV info. 2496 2497 arg4 - The request ID, is used in non-blocking mode only and can be ignored in blocking mode. 2498 2499 arg5 - The cookie variable, is used in non-blocking mode only and can be ignored in blocking 2500 mode. 2501 2502The function returns E_RMM_OK on success, E_RMM_INVAL if arguments are invalid, E_RMM_FAULT 2503if the key programming is unsuccesful, E_RMM_UNK for an unknown error, E_RMM_AGAIN returned 2504only for non-blocking mode if the IDE-KM interface is busy or the request queue is full. 2505E_RMM_INPROGRESS returned if the request is queued successfully and used only in non-blocking 2506mode. 2507 2508Function : plat_rmmd_el3_ide_key_set_go() [mandatory when RMMD_ENABLE_IDE_KEY_PROG == 1] 2509~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 2510 2511:: 2512 2513 Argument : uint64_t, uint64_t, uint64_t, uint64_t, uint64_t 2514 Return : int 2515 2516This function activates the IDE stream at the Root Port once all the keys have been 2517programmed. The platform should validate the arguments `Ecam address` and `Rootport ID` 2518before acting on it. The arguments `request ID` and `cookie` are to be ignored for blocking 2519mode and are pass-through to the response for non-blocking mode. 2520 2521The platform needs to ensure proper exclusives are in place when accessed from multiple CPUs. 2522Depending on the expected latency for IDE-KM interface, the platform should choose blocking 2523or non-blocking semantics. More details about IDE Setup flow can be found 2524in this `RFC <https://github.com/TF-RMM/tf-rmm/wiki/RFC:-EL3-RMM-IDE-KM-Interface>`_. 2525 2526The parameters of the function are: 2527 2528 arg0 - The ecam address, to access and configure PCI devices in a system. 2529 2530 arg1 - The rootport ID used to identify the PCIe rootport of a connected device. 2531 2532 arg2 - The IDE stream info associated with a physical device, this parameter packs the 2533 the keyset, direction, substream and stream ID info. 2534 2535 arg3 - The request ID, is used in non-blocking mode only and can be ignored in blocking mode. 2536 2537 arg4 - The cookie variable, is used in non-blocking mode only and can be ignored in blocking 2538 mode. 2539 2540The function returns E_RMM_OK on success, E_RMM_INVAL if arguments are invalid, E_RMM_FAULT 2541if the key programming is unsuccesful, E_RMM_UNK for an unknown error, E_RMM_AGAIN returned 2542only for non-blocking mode if the IDE-KM interface is busy or the request queue is full. 2543E_RMM_INPROGRESS returned if the request is queued successfully and used only in non-blocking 2544mode. 2545 2546Function : plat_rmmd_el3_ide_key_set_stop() [mandatory when RMMD_ENABLE_IDE_KEY_PROG == 1] 2547~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 2548 2549:: 2550 2551 Argument : uint64_t, uint64_t, uint64_t, uint64_t, uint64_t 2552 Return : int 2553 2554This function stops the IDE stream and is used to tear down the IDE stream at Root Port. 2555The platform should validate the arguments `Ecam address` and `Rootport ID` before acting 2556on it. The arguments `request ID` and `cookie` are to be ignored for blocking 2557mode and are pass-through to the response for non-blocking mode. 2558 2559The platform needs to ensure proper exclusives are in place when accessed from multiple CPUs. 2560Depending on the expected latency for IDE-KM interface, the platform should choose blocking 2561or non-blocking semantics. More details about IDE Setup flow can be found 2562in this `RFC <https://github.com/TF-RMM/tf-rmm/wiki/RFC:-EL3-RMM-IDE-KM-Interface>`_. 2563 2564The parameters of the function are: 2565 2566 arg0 - The ecam address, to access and configure PCI devices in a system. 2567 2568 arg1 - The rootport ID used to identify the PCIe rootport of a connected device. 2569 2570 arg2 - The IDE stream info associated with a physical device, this parameter packs the 2571 the keyset, direction, substream and stream ID info. 2572 2573 arg3 - The request ID, is used in non-blocking mode only and can be ignored in blocking mode. 2574 2575 arg4 - The cookie variable, is used in non-blocking mode only and can be ignored in blocking 2576 mode. 2577 2578The function returns E_RMM_OK on success, E_RMM_INVAL if arguments are invalid, E_RMM_FAULT 2579if the key programming is unsuccesful, E_RMM_UNK for an unknown error, E_RMM_AGAIN returned 2580only for non-blocking mode if the IDE-KM interface is busy or the request queue is full. 2581E_RMM_INPROGRESS returned if the request is queued successfully and used only in non-blocking 2582mode. 2583 2584Function : plat_rmmd_el3_ide_km_pull_response() [mandatory when RMMD_ENABLE_IDE_KEY_PROG == 1] 2585~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 2586 2587:: 2588 2589 Argument : uint64_t, uint64_t, uint64_t *, uint64_t *, uint64_t * 2590 Return : int 2591 2592This function retrieves a reponse for any of the prior non-blocking IDE-KM requests. The 2593caller has to identify the request and populate the accurate response. For blocking calls, 2594this function always returns E_RMM_UNK. 2595 2596The platform needs to ensure proper exclusives are in place when accessed from multiple CPUs. 2597Depending on the expected latency for IDE-KM interface, the platform should choose blocking 2598or non-blocking semantics. More details about IDE Setup flow can be found 2599in this `RFC <https://github.com/TF-RMM/tf-rmm/wiki/RFC:-EL3-RMM-IDE-KM-Interface>`_. 2600 2601The parameters of the function are: 2602 2603 arg0 - The ecam address, to access and configure PCI devices in a system. 2604 2605 arg1 - The rootport ID used to identify the PCIe rootport of a connected device. 2606 2607 arg2 - Retrieved response corresponding to the previous IDE_KM request. 2608 2609 arg3 - returns the passthrough request ID of the retrieved response. 2610 2611 arg4 - returns the passthrough cookie of the retrieved response. 2612 2613The function returns E_RMM_OK if response is retrieved successfully, E_RMM_INVAL if arguments 2614to this function are invalid, E_RMM_UNK if response retrieval failed for an unknown error or 2615IDE-KM interface is having blocking semantics, E_RMM_AGAIN if the response queue is empty. 2616 2617The `arg2` return parameter can return the following values: 2618E_RMM_OK - The previous request was successful. 2619E_RMM_FAULT - The previous request was not successful. 2620E_RMM_INVAL - Arguments to previous request were incorrect. 2621E_RMM_UNK - Previous request returned Unknown error. 2622 2623Function : bl31_plat_enable_mmu [optional] 2624~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 2625 2626:: 2627 2628 Argument : uint32_t 2629 Return : void 2630 2631This function enables the MMU. The boot code calls this function with MMU and 2632caches disabled. This function should program necessary registers to enable 2633translation, and upon return, the MMU on the calling PE must be enabled. 2634 2635The function must honor flags passed in the first argument. These flags are 2636defined by the translation library, and can be found in the file 2637``include/lib/xlat_tables/xlat_mmu_helpers.h``. 2638 2639On DynamIQ systems, this function must not use stack while enabling MMU, which 2640is how the function in xlat table library version 2 is implemented. 2641 2642Function : plat_init_apkey [optional] 2643~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 2644 2645:: 2646 2647 Argument : void 2648 Return : uint128_t 2649 2650This function returns the 128-bit value which can be used to program ARMv8.3 2651pointer authentication keys. 2652 2653The value should be obtained from a reliable source of randomness. 2654 2655This function is only needed if ARMv8.3 pointer authentication is used in the 2656Trusted Firmware by building with ``BRANCH_PROTECTION`` option set to 1, 2 or 3. 2657 2658Function : plat_get_syscnt_freq2() [mandatory] 2659~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 2660 2661:: 2662 2663 Argument : void 2664 Return : unsigned int 2665 2666This function is used by the architecture setup code to retrieve the counter 2667frequency for the CPU's generic timer. This value will be programmed into the 2668``CNTFRQ_EL0`` register. In Arm standard platforms, it returns the base frequency 2669of the system counter, which is retrieved from the first entry in the frequency 2670modes table. 2671 2672#define : PLAT_PERCPU_BAKERY_LOCK_SIZE [optional] 2673~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 2674 2675When ``USE_COHERENT_MEM = 0``, this constant defines the total memory (in 2676bytes) aligned to the cache line boundary that should be allocated per-cpu to 2677accommodate all the bakery locks. 2678 2679If this constant is not defined when ``USE_COHERENT_MEM = 0``, the linker 2680calculates the size of the ``.bakery_lock`` input section, aligns it to the 2681nearest ``CACHE_WRITEBACK_GRANULE``, multiplies it with ``PLATFORM_CORE_COUNT`` 2682and stores the result in a linker symbol. This constant prevents a platform 2683from relying on the linker and provide a more efficient mechanism for 2684accessing per-cpu bakery lock information. 2685 2686If this constant is defined and its value is not equal to the value 2687calculated by the linker then a link time assertion is raised. A compile time 2688assertion is raised if the value of the constant is not aligned to the cache 2689line boundary. 2690 2691.. _porting_guide_sdei_requirements: 2692 2693SDEI porting requirements 2694~~~~~~~~~~~~~~~~~~~~~~~~~ 2695 2696The |SDEI| dispatcher requires the platform to provide the following macros 2697and functions, of which some are optional, and some others mandatory. 2698 2699Macros 2700...... 2701 2702Macro: PLAT_SDEI_NORMAL_PRI [mandatory] 2703^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 2704 2705This macro must be defined to the EL3 exception priority level associated with 2706Normal |SDEI| events on the platform. This must have a higher value 2707(therefore of lower priority) than ``PLAT_SDEI_CRITICAL_PRI``. 2708 2709Macro: PLAT_SDEI_CRITICAL_PRI [mandatory] 2710^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 2711 2712This macro must be defined to the EL3 exception priority level associated with 2713Critical |SDEI| events on the platform. This must have a lower value 2714(therefore of higher priority) than ``PLAT_SDEI_NORMAL_PRI``. 2715 2716**Note**: |SDEI| exception priorities must be the lowest among Secure 2717priorities. Among the |SDEI| exceptions, Critical |SDEI| priority must 2718be higher than Normal |SDEI| priority. 2719 2720Functions 2721......... 2722 2723Function: int plat_sdei_validate_entry_point() [optional] 2724^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 2725 2726:: 2727 2728 Argument: uintptr_t ep, unsigned int client_mode 2729 Return: int 2730 2731This function validates the entry point address of the event handler provided by 2732the client for both event registration and *Complete and Resume* |SDEI| calls. 2733The function ensures that the address is valid in the client translation regime. 2734 2735The second argument is the exception level that the client is executing in. It 2736can be Non-Secure EL1 or Non-Secure EL2. 2737 2738The function must return ``0`` for successful validation, or ``-1`` upon failure. 2739 2740The default implementation always returns ``0``. On Arm platforms, this function 2741translates the entry point address within the client translation regime and 2742further ensures that the resulting physical address is located in Non-secure 2743DRAM. 2744 2745Function: void plat_sdei_handle_masked_trigger(uint64_t mpidr, unsigned int intr) [optional] 2746^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 2747 2748:: 2749 2750 Argument: uint64_t 2751 Argument: unsigned int 2752 Return: void 2753 2754|SDEI| specification requires that a PE comes out of reset with the events 2755masked. The client therefore is expected to call ``PE_UNMASK`` to unmask 2756|SDEI| events on the PE. No |SDEI| events can be dispatched until such 2757time. 2758 2759Should a PE receive an interrupt that was bound to an |SDEI| event while the 2760events are masked on the PE, the dispatcher implementation invokes the function 2761``plat_sdei_handle_masked_trigger``. The MPIDR of the PE that received the 2762interrupt and the interrupt ID are passed as parameters. 2763 2764The default implementation only prints out a warning message. 2765 2766.. _porting_guide_trng_requirements: 2767 2768TRNG porting requirements 2769~~~~~~~~~~~~~~~~~~~~~~~~~ 2770 2771The |TRNG| backend requires the platform to provide the following values 2772and mandatory functions. 2773 2774Values 2775...... 2776 2777value: uuid_t plat_trng_uuid [mandatory] 2778^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 2779 2780This value must be defined to the UUID of the TRNG backend that is specific to 2781the hardware after ``plat_entropy_setup`` function is called. This value must 2782conform to the SMCCC calling convention; The most significant 32 bits of the 2783UUID must not equal ``0xffffffff`` or the signed integer ``-1`` as this value in 2784w0 indicates failure to get a TRNG source. 2785 2786Functions 2787......... 2788 2789Function: void plat_entropy_setup(void) [mandatory] 2790^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 2791 2792:: 2793 2794 Argument: none 2795 Return: none 2796 2797This function is expected to do platform-specific initialization of any TRNG 2798hardware. This may include generating a UUID from a hardware-specific seed. 2799 2800Function: bool plat_get_entropy(uint64_t \*out) [mandatory] 2801^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 2802 2803:: 2804 2805 Argument: uint64_t * 2806 Return: bool 2807 Out : when the return value is true, the entropy has been written into the 2808 storage pointed to 2809 2810This function writes entropy into storage provided by the caller. If no entropy 2811is available, it must return false and the storage must not be written. 2812 2813.. _psci_in_bl31: 2814 2815Power State Coordination Interface (in BL31) 2816-------------------------------------------- 2817 2818The TF-A implementation of the PSCI API is based around the concept of a 2819*power domain*. A *power domain* is a CPU or a logical group of CPUs which 2820share some state on which power management operations can be performed as 2821specified by `PSCI`_. Each CPU in the system is assigned a cpu index which is 2822a unique number between ``0`` and ``PLATFORM_CORE_COUNT - 1``. The 2823*power domains* are arranged in a hierarchical tree structure and each 2824*power domain* can be identified in a system by the cpu index of any CPU that 2825is part of that domain and a *power domain level*. A processing element (for 2826example, a CPU) is at level 0. If the *power domain* node above a CPU is a 2827logical grouping of CPUs that share some state, then level 1 is that group of 2828CPUs (for example, a cluster), and level 2 is a group of clusters (for 2829example, the system). More details on the power domain topology and its 2830organization can be found in :ref:`PSCI Power Domain Tree Structure`. 2831 2832BL31's platform initialization code exports a pointer to the platform-specific 2833power management operations required for the PSCI implementation to function 2834correctly. This information is populated in the ``plat_psci_ops`` structure. The 2835PSCI implementation calls members of the ``plat_psci_ops`` structure for performing 2836power management operations on the power domains. For example, the target 2837CPU is specified by its ``MPIDR`` in a PSCI ``CPU_ON`` call. The ``pwr_domain_on()`` 2838handler (if present) is called for the CPU power domain. 2839 2840The ``power-state`` parameter of a PSCI ``CPU_SUSPEND`` call can be used to 2841describe composite power states specific to a platform. The PSCI implementation 2842defines a generic representation of the power-state parameter, which is an 2843array of local power states where each index corresponds to a power domain 2844level. Each entry contains the local power state the power domain at that power 2845level could enter. It depends on the ``validate_power_state()`` handler to 2846convert the power-state parameter (possibly encoding a composite power state) 2847passed in a PSCI ``CPU_SUSPEND`` call to this representation. 2848 2849The following functions form part of platform port of PSCI functionality. 2850 2851Function : plat_psci_stat_accounting_start() [optional] 2852~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 2853 2854:: 2855 2856 Argument : const psci_power_state_t * 2857 Return : void 2858 2859This is an optional hook that platforms can implement for residency statistics 2860accounting before entering a low power state. The ``pwr_domain_state`` field of 2861``state_info`` (first argument) can be inspected if stat accounting is done 2862differently at CPU level versus higher levels. As an example, if the element at 2863index 0 (CPU power level) in the ``pwr_domain_state`` array indicates a power down 2864state, special hardware logic may be programmed in order to keep track of the 2865residency statistics. For higher levels (array indices > 0), the residency 2866statistics could be tracked in software using PMF. If ``ENABLE_PMF`` is set, the 2867default implementation will use PMF to capture timestamps. 2868 2869Function : plat_psci_stat_accounting_stop() [optional] 2870~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 2871 2872:: 2873 2874 Argument : const psci_power_state_t * 2875 Return : void 2876 2877This is an optional hook that platforms can implement for residency statistics 2878accounting after exiting from a low power state. The ``pwr_domain_state`` field 2879of ``state_info`` (first argument) can be inspected if stat accounting is done 2880differently at CPU level versus higher levels. As an example, if the element at 2881index 0 (CPU power level) in the ``pwr_domain_state`` array indicates a power down 2882state, special hardware logic may be programmed in order to keep track of the 2883residency statistics. For higher levels (array indices > 0), the residency 2884statistics could be tracked in software using PMF. If ``ENABLE_PMF`` is set, the 2885default implementation will use PMF to capture timestamps. 2886 2887Function : plat_psci_stat_get_residency() [optional] 2888~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 2889 2890:: 2891 2892 Argument : unsigned int, const psci_power_state_t *, unsigned int 2893 Return : u_register_t 2894 2895This is an optional interface that is is invoked after resuming from a low power 2896state and provides the time spent resident in that low power state by the power 2897domain at a particular power domain level. When a CPU wakes up from suspend, 2898all its parent power domain levels are also woken up. The generic PSCI code 2899invokes this function for each parent power domain that is resumed and it 2900identified by the ``lvl`` (first argument) parameter. The ``state_info`` (second 2901argument) describes the low power state that the power domain has resumed from. 2902The current CPU is the first CPU in the power domain to resume from the low 2903power state and the ``last_cpu_idx`` (third parameter) is the index of the last 2904CPU in the power domain to suspend and may be needed to calculate the residency 2905for that power domain. 2906 2907Function : plat_get_target_pwr_state() [optional] 2908~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 2909 2910:: 2911 2912 Argument : unsigned int, const plat_local_state_t *, unsigned int 2913 Return : plat_local_state_t 2914 2915The PSCI generic code uses this function to let the platform participate in 2916state coordination during a power management operation. The function is passed 2917a pointer to an array of platform specific local power state ``states`` (second 2918argument) which contains the requested power state for each CPU at a particular 2919power domain level ``lvl`` (first argument) within the power domain. The function 2920is expected to traverse this array of upto ``ncpus`` (third argument) and return 2921a coordinated target power state by the comparing all the requested power 2922states. The target power state should not be deeper than any of the requested 2923power states. 2924 2925A weak definition of this API is provided by default wherein it assumes 2926that the platform assigns a local state value in order of increasing depth 2927of the power state i.e. for two power states X & Y, if X < Y 2928then X represents a shallower power state than Y. As a result, the 2929coordinated target local power state for a power domain will be the minimum 2930of the requested local power state values. 2931 2932Function : plat_get_power_domain_tree_desc() [mandatory] 2933~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 2934 2935:: 2936 2937 Argument : void 2938 Return : const unsigned char * 2939 2940This function returns a pointer to the byte array containing the power domain 2941topology tree description. The format and method to construct this array are 2942described in :ref:`PSCI Power Domain Tree Structure`. The BL31 PSCI 2943initialization code requires this array to be described by the platform, either 2944statically or dynamically, to initialize the power domain topology tree. In case 2945the array is populated dynamically, then plat_core_pos_by_mpidr() and 2946plat_my_core_pos() should also be implemented suitably so that the topology tree 2947description matches the CPU indices returned by these APIs. These APIs together 2948form the platform interface for the PSCI topology framework. 2949 2950Function : plat_setup_psci_ops() [mandatory] 2951~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 2952 2953:: 2954 2955 Argument : uintptr_t, const plat_psci_ops ** 2956 Return : int 2957 2958This function may execute with the MMU and data caches enabled if the platform 2959port does the necessary initializations in ``bl31_plat_arch_setup()``. It is only 2960called by the primary CPU. 2961 2962This function is called by PSCI initialization code. Its purpose is to let 2963the platform layer know about the warm boot entrypoint through the 2964``sec_entrypoint`` (first argument) and to export handler routines for 2965platform-specific psci power management actions by populating the passed 2966pointer with a pointer to BL31's private ``plat_psci_ops`` structure. 2967 2968A description of each member of this structure is given below. Please refer to 2969the Arm FVP specific implementation of these handlers in 2970``plat/arm/board/fvp/fvp_pm.c`` as an example. For each PSCI function that the 2971platform wants to support, the associated operation or operations in this 2972structure must be provided and implemented (Refer section 4 of 2973:ref:`Firmware Design` for the PSCI API supported in TF-A). To disable a PSCI 2974function in a platform port, the operation should be removed from this 2975structure instead of providing an empty implementation. 2976 2977plat_psci_ops.cpu_standby() 2978........................... 2979 2980Perform the platform-specific actions to enter the standby state for a cpu 2981indicated by the passed argument. This provides a fast path for CPU standby 2982wherein overheads of PSCI state management and lock acquisition is avoided. 2983For this handler to be invoked by the PSCI ``CPU_SUSPEND`` API implementation, 2984the suspend state type specified in the ``power-state`` parameter should be 2985STANDBY and the target power domain level specified should be the CPU. The 2986handler should put the CPU into a low power retention state (usually by 2987issuing a wfi instruction) and ensure that it can be woken up from that 2988state by a normal interrupt. The generic code expects the handler to succeed. 2989 2990plat_psci_ops.pwr_domain_on() 2991............................. 2992 2993Perform the platform specific actions to power on a CPU, specified 2994by the ``MPIDR`` (first argument). The generic code expects the platform to 2995return PSCI_E_SUCCESS on success or PSCI_E_INTERN_FAIL for any failure. 2996 2997plat_psci_ops.pwr_domain_off_early() [optional] 2998............................................... 2999 3000This optional function performs the platform specific actions to check if 3001powering off the calling CPU and its higher parent power domain levels as 3002indicated by the ``target_state`` (first argument) is possible or allowed. 3003 3004The ``target_state`` encodes the platform coordinated target local power states 3005for the CPU power domain and its parent power domain levels. 3006 3007For this handler, the local power state for the CPU power domain will be a 3008power down state where as it could be either power down, retention or run state 3009for the higher power domain levels depending on the result of state 3010coordination. The generic code expects PSCI_E_DENIED return code if the 3011platform thinks that CPU_OFF should not proceed on the calling CPU. 3012 3013plat_psci_ops.pwr_domain_off() 3014.............................. 3015 3016Perform the platform specific actions to prepare to power off the calling CPU 3017and its higher parent power domain levels as indicated by the ``target_state`` 3018(first argument). It is called by the PSCI ``CPU_OFF`` API implementation. 3019 3020The ``target_state`` encodes the platform coordinated target local power states 3021for the CPU power domain and its parent power domain levels. The handler 3022needs to perform power management operation corresponding to the local state 3023at each power level. 3024 3025For this handler, the local power state for the CPU power domain will be a 3026power down state where as it could be either power down, retention or run state 3027for the higher power domain levels depending on the result of state 3028coordination. The generic code expects the handler to succeed. 3029 3030plat_psci_ops.pwr_domain_validate_suspend() [optional] 3031...................................................... 3032 3033This is an optional function that is only compiled into the build if the build 3034option ``PSCI_OS_INIT_MODE`` is enabled. 3035 3036If implemented, this function allows the platform to perform platform specific 3037validations based on hardware states. The generic code expects this function to 3038return PSCI_E_SUCCESS on success, or either PSCI_E_DENIED or 3039PSCI_E_INVALID_PARAMS as appropriate for any invalid requests. 3040 3041plat_psci_ops.pwr_domain_suspend_pwrdown_early() [optional] 3042........................................................... 3043 3044This optional function may be used as a performance optimization to replace 3045or complement pwr_domain_suspend() on some platforms. Its calling semantics 3046are identical to pwr_domain_suspend(), except the PSCI implementation only 3047calls this function when suspending to a power down state, and it guarantees 3048that data caches are enabled. 3049 3050When HW_ASSISTED_COHERENCY = 0, the PSCI implementation disables data caches 3051before calling pwr_domain_suspend(). If the target_state corresponds to a 3052power down state and it is safe to perform some or all of the platform 3053specific actions in that function with data caches enabled, it may be more 3054efficient to move those actions to this function. When HW_ASSISTED_COHERENCY 3055= 1, data caches remain enabled throughout, and so there is no advantage to 3056moving platform specific actions to this function. 3057 3058plat_psci_ops.pwr_domain_suspend() 3059.................................. 3060 3061Perform the platform specific actions to prepare to suspend the calling 3062CPU and its higher parent power domain levels as indicated by the 3063``target_state`` (first argument). It is called by the PSCI ``CPU_SUSPEND`` 3064API implementation. 3065 3066The ``target_state`` has a similar meaning as described in 3067the ``pwr_domain_off()`` operation. It encodes the platform coordinated 3068target local power states for the CPU power domain and its parent 3069power domain levels. The handler needs to perform power management operation 3070corresponding to the local state at each power level. The generic code 3071expects the handler to succeed. 3072 3073The difference between turning a power domain off versus suspending it is that 3074in the former case, the power domain is expected to re-initialize its state 3075when it is next powered on (see ``pwr_domain_on_finish()``). In the latter 3076case, the power domain is expected to save enough state so that it can resume 3077execution by restoring this state when its powered on (see 3078``pwr_domain_suspend_finish()``). 3079 3080When suspending a core, the platform can also choose to power off the GICv3 3081Redistributor and ITS through an implementation-defined sequence. To achieve 3082this safely, the ITS context must be saved first. The architectural part is 3083implemented by the ``gicv3_its_save_disable()`` helper, but most of the needed 3084sequence is implementation defined and it is therefore the responsibility of 3085the platform code to implement the necessary sequence. Then the GIC 3086Redistributor context can be saved using the ``gicv3_rdistif_save()`` helper. 3087Powering off the Redistributor requires the implementation to support it and it 3088is the responsibility of the platform code to execute the right implementation 3089defined sequence. 3090 3091When a system suspend is requested, the platform can also make use of the 3092``gicv3_distif_save()`` helper to save the context of the GIC Distributor after 3093it has saved the context of the Redistributors and ITS of all the cores in the 3094system. The context of the Distributor can be large and may require it to be 3095allocated in a special area if it cannot fit in the platform's global static 3096data, for example in DRAM. The Distributor can then be powered down using an 3097implementation-defined sequence. 3098 3099plat_psci_ops.pwr_domain_pwr_down() 3100....................................... 3101 3102This is an optional function and, if implemented, is expected to perform 3103platform specific actions before the CPU is powered down. Since this function is 3104invoked outside the PSCI locks, the actions performed in this hook must be local 3105to the CPU or the platform must ensure that races between multiple CPUs cannot 3106occur. 3107 3108The ``target_state`` has a similar meaning as described in the ``pwr_domain_off()`` 3109operation and it encodes the platform coordinated target local power states for 3110the CPU power domain and its parent power domain levels. 3111 3112It is preferred that this function returns. The caller will invoke 3113``wfi()`` to powerdown the CPU, mitigate any powerdown errata, 3114and handle any wakeups that may arise. Previously, this function did not return 3115and instead called ``wfi`` (in an infinite loop) directly. This is still 3116possible on platforms where this is guaranteed to be terminal, however, it is 3117strongly discouraged going forward. 3118 3119Previously this function was called ``pwr_domain_pwr_down_wfi()`` and invoked 3120``psci_power_down_wfi()`` (now removed). 3121 3122plat_psci_ops.pwr_domain_on_finish() 3123.................................... 3124 3125This function is called by the PSCI implementation after the calling CPU is 3126powered on and released from reset in response to an earlier PSCI ``CPU_ON`` call. 3127It performs the platform-specific setup required to initialize enough state for 3128this CPU to enter the normal world and also provide secure runtime firmware 3129services. 3130 3131The ``target_state`` (first argument) is the prior state of the power domains 3132immediately before the CPU was turned on. It indicates which power domains 3133above the CPU might require initialization due to having previously been in 3134low power states. The generic code expects the handler to succeed. 3135 3136plat_psci_ops.pwr_domain_on_finish_late() [optional] 3137........................................................... 3138 3139This optional function is called by the PSCI implementation after the calling 3140CPU is fully powered on with respective data caches enabled. The calling CPU and 3141the associated cluster are guaranteed to be participating in coherency. This 3142function gives the flexibility to perform any platform-specific actions safely, 3143such as initialization or modification of shared data structures, without the 3144overhead of explicit cache maintainace operations. 3145 3146The ``target_state`` has a similar meaning as described in the ``pwr_domain_on_finish()`` 3147operation. The generic code expects the handler to succeed. 3148 3149plat_psci_ops.pwr_domain_suspend_finish() 3150......................................... 3151 3152This function is called by the PSCI implementation after the calling CPU is 3153powered on and released from reset in response to an asynchronous wakeup 3154event, for example a timer interrupt that was programmed by the CPU during the 3155``CPU_SUSPEND`` call or ``SYSTEM_SUSPEND`` call. It performs the platform-specific 3156setup required to restore the saved state for this CPU to resume execution 3157in the normal world and also provide secure runtime firmware services. 3158 3159The ``target_state`` (first argument) has a similar meaning as described in 3160the ``pwr_domain_on_finish()`` operation. The generic code expects the platform 3161to succeed. 3162 3163If the Distributor, Redistributors or ITS have been powered off as part of a 3164suspend, their context must be restored in this function in the reverse order 3165to how they were saved during suspend sequence. 3166 3167plat_psci_ops.system_off() 3168.......................... 3169 3170This function is called by PSCI implementation in response to a ``SYSTEM_OFF`` 3171call. It performs the platform-specific system poweroff sequence after 3172notifying the Secure Payload Dispatcher. The caller will call ``wfi`` if this 3173function returns, similar to `plat_psci_ops.pwr_domain_pwr_down()`_. 3174 3175plat_psci_ops.system_reset() 3176............................ 3177 3178This function is called by PSCI implementation in response to a ``SYSTEM_RESET`` 3179call. It performs the platform-specific system reset sequence after 3180notifying the Secure Payload Dispatcher. The caller will call ``wfi`` if this 3181function returns, similar to `plat_psci_ops.pwr_domain_pwr_down()`_. 3182 3183plat_psci_ops.validate_power_state() 3184.................................... 3185 3186This function is called by the PSCI implementation during the ``CPU_SUSPEND`` 3187call to validate the ``power_state`` parameter of the PSCI API and if valid, 3188populate it in ``req_state`` (second argument) array as power domain level 3189specific local states. If the ``power_state`` is invalid, the platform must 3190return PSCI_E_INVALID_PARAMS as error, which is propagated back to the 3191normal world PSCI client. 3192 3193plat_psci_ops.validate_ns_entrypoint() 3194...................................... 3195 3196This function is called by the PSCI implementation during the ``CPU_SUSPEND``, 3197``SYSTEM_SUSPEND`` and ``CPU_ON`` calls to validate the non-secure ``entry_point`` 3198parameter passed by the normal world. If the ``entry_point`` is invalid, 3199the platform must return PSCI_E_INVALID_ADDRESS as error, which is 3200propagated back to the normal world PSCI client. 3201 3202plat_psci_ops.get_sys_suspend_power_state() 3203........................................... 3204 3205This function is called by the PSCI implementation during the ``SYSTEM_SUSPEND`` 3206call to get the ``req_state`` parameter from platform which encodes the power 3207domain level specific local states to suspend to system affinity level. The 3208``req_state`` will be utilized to do the PSCI state coordination and 3209``pwr_domain_suspend()`` will be invoked with the coordinated target state to 3210enter system suspend. 3211 3212plat_psci_ops.get_pwr_lvl_state_idx() 3213..................................... 3214 3215This is an optional function and, if implemented, is invoked by the PSCI 3216implementation to convert the ``local_state`` (first argument) at a specified 3217``pwr_lvl`` (second argument) to an index between 0 and 3218``PLAT_MAX_PWR_LVL_STATES`` - 1. This function is only needed if the platform 3219supports more than two local power states at each power domain level, that is 3220``PLAT_MAX_PWR_LVL_STATES`` is greater than 2, and needs to account for these 3221local power states. 3222 3223plat_psci_ops.translate_power_state_by_mpidr() 3224.............................................. 3225 3226This is an optional function and, if implemented, verifies the ``power_state`` 3227(second argument) parameter of the PSCI API corresponding to a target power 3228domain. The target power domain is identified by using both ``MPIDR`` (first 3229argument) and the power domain level encoded in ``power_state``. The power domain 3230level specific local states are to be extracted from ``power_state`` and be 3231populated in the ``output_state`` (third argument) array. The functionality 3232is similar to the ``validate_power_state`` function described above and is 3233envisaged to be used in case the validity of ``power_state`` depend on the 3234targeted power domain. If the ``power_state`` is invalid for the targeted power 3235domain, the platform must return PSCI_E_INVALID_PARAMS as error. If this 3236function is not implemented, then the generic implementation relies on 3237``validate_power_state`` function to translate the ``power_state``. 3238 3239This function can also be used in case the platform wants to support local 3240power state encoding for ``power_state`` parameter of PSCI_STAT_COUNT/RESIDENCY 3241APIs as described in Section 5.18 of `PSCI`_. 3242 3243plat_psci_ops.get_node_hw_state() 3244................................. 3245 3246This is an optional function. If implemented this function is intended to return 3247the power state of a node (identified by the first parameter, the ``MPIDR``) in 3248the power domain topology (identified by the second parameter, ``power_level``), 3249as retrieved from a power controller or equivalent component on the platform. 3250Upon successful completion, the implementation must map and return the final 3251status among ``HW_ON``, ``HW_OFF`` or ``HW_STANDBY``. Upon encountering failures, it 3252must return either ``PSCI_E_INVALID_PARAMS`` or ``PSCI_E_NOT_SUPPORTED`` as 3253appropriate. 3254 3255Implementations are not expected to handle ``power_levels`` greater than 3256``PLAT_MAX_PWR_LVL``. 3257 3258plat_psci_ops.system_reset2() 3259............................. 3260 3261This is an optional function. If implemented this function is 3262called during the ``SYSTEM_RESET2`` call to perform a reset 3263based on the first parameter ``reset_type`` as specified in 3264`PSCI`_. The parameter ``cookie`` can be used to pass additional 3265reset information. If the ``reset_type`` is not supported, the 3266function must return ``PSCI_E_NOT_SUPPORTED``. For architectural 3267resets, all failures must return ``PSCI_E_INVALID_PARAMETERS`` 3268and vendor reset can return other PSCI error codes as defined 3269in `PSCI`_. If this function returns success, the caller will call 3270``wfi`` similar to `plat_psci_ops.pwr_domain_pwr_down()`_. 3271 3272plat_psci_ops.write_mem_protect() 3273................................. 3274 3275This is an optional function. If implemented it enables or disables the 3276``MEM_PROTECT`` functionality based on the value of ``val``. 3277A non-zero value enables ``MEM_PROTECT`` and a value of zero 3278disables it. Upon encountering failures it must return a negative value 3279and on success it must return 0. 3280 3281plat_psci_ops.read_mem_protect() 3282................................ 3283 3284This is an optional function. If implemented it returns the current 3285state of ``MEM_PROTECT`` via the ``val`` parameter. Upon encountering 3286failures it must return a negative value and on success it must 3287return 0. 3288 3289plat_psci_ops.mem_protect_chk() 3290............................... 3291 3292This is an optional function. If implemented it checks if a memory 3293region defined by a base address ``base`` and with a size of ``length`` 3294bytes is protected by ``MEM_PROTECT``. If the region is protected 3295then it must return 0, otherwise it must return a negative number. 3296 3297.. _porting_guide_imf_in_bl31: 3298 3299Interrupt Management framework (in BL31) 3300---------------------------------------- 3301 3302BL31 implements an Interrupt Management Framework (IMF) to manage interrupts 3303generated in either security state and targeted to EL1 or EL2 in the non-secure 3304state or EL3/S-EL1 in the secure state. The design of this framework is 3305described in the :ref:`Interrupt Management Framework` 3306 3307A platform should export the following APIs to support the IMF. The following 3308text briefly describes each API and its implementation in Arm standard 3309platforms. The API implementation depends upon the type of interrupt controller 3310present in the platform. Arm standard platform layer supports both 3311`Arm Generic Interrupt Controller version 2.0 (GICv2)`_ 3312and `3.0 (GICv3)`_. Juno builds the Arm platform layer to use GICv2 and the 3313FVP can be configured to use either GICv2 or GICv3 depending on the build flag 3314``FVP_USE_GIC_DRIVER`` (See :ref:`build_options_arm_fvp_platform` for more 3315details). 3316 3317See also: :ref:`Interrupt Controller Abstraction APIs<Platform Interrupt Controller API>`. 3318 3319Function : plat_interrupt_type_to_line() [mandatory] 3320~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 3321 3322:: 3323 3324 Argument : uint32_t, uint32_t 3325 Return : uint32_t 3326 3327The Arm processor signals an interrupt exception either through the IRQ or FIQ 3328interrupt line. The specific line that is signaled depends on how the interrupt 3329controller (IC) reports different interrupt types from an execution context in 3330either security state. The IMF uses this API to determine which interrupt line 3331the platform IC uses to signal each type of interrupt supported by the framework 3332from a given security state. This API must be invoked at EL3. 3333 3334The first parameter will be one of the ``INTR_TYPE_*`` values (see 3335:ref:`Interrupt Management Framework`) indicating the target type of the 3336interrupt, the second parameter is the security state of the originating 3337execution context. The return result is the bit position in the ``SCR_EL3`` 3338register of the respective interrupt trap: IRQ=1, FIQ=2. 3339 3340In the case of Arm standard platforms using GICv2, S-EL1 interrupts are 3341configured as FIQs and Non-secure interrupts as IRQs from either security 3342state. 3343 3344In the case of Arm standard platforms using GICv3, the interrupt line to be 3345configured depends on the security state of the execution context when the 3346interrupt is signalled and are as follows: 3347 3348- The S-EL1 interrupts are signaled as IRQ in S-EL0/1 context and as FIQ in 3349 NS-EL0/1/2 context. 3350- The Non secure interrupts are signaled as FIQ in S-EL0/1 context and as IRQ 3351 in the NS-EL0/1/2 context. 3352- The EL3 interrupts are signaled as FIQ in both S-EL0/1 and NS-EL0/1/2 3353 context. 3354 3355Function : plat_ic_get_pending_interrupt_type() [mandatory] 3356~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 3357 3358:: 3359 3360 Argument : void 3361 Return : uint32_t 3362 3363This API returns the type of the highest priority pending interrupt at the 3364platform IC. The IMF uses the interrupt type to retrieve the corresponding 3365handler function. ``INTR_TYPE_INVAL`` is returned when there is no interrupt 3366pending. The valid interrupt types that can be returned are ``INTR_TYPE_EL3``, 3367``INTR_TYPE_S_EL1`` and ``INTR_TYPE_NS``. This API must be invoked at EL3. 3368 3369In the case of Arm standard platforms using GICv2, the *Highest Priority 3370Pending Interrupt Register* (``GICC_HPPIR``) is read to determine the id of 3371the pending interrupt. The type of interrupt depends upon the id value as 3372follows. 3373 3374#. id < 1022 is reported as a S-EL1 interrupt 3375#. id = 1022 is reported as a Non-secure interrupt. 3376#. id = 1023 is reported as an invalid interrupt type. 3377 3378In the case of Arm standard platforms using GICv3, the system register 3379``ICC_HPPIR0_EL1``, *Highest Priority Pending group 0 Interrupt Register*, 3380is read to determine the id of the pending interrupt. The type of interrupt 3381depends upon the id value as follows. 3382 3383#. id = ``PENDING_G1S_INTID`` (1020) is reported as a S-EL1 interrupt 3384#. id = ``PENDING_G1NS_INTID`` (1021) is reported as a Non-secure interrupt. 3385#. id = ``GIC_SPURIOUS_INTERRUPT`` (1023) is reported as an invalid interrupt type. 3386#. All other interrupt id's are reported as EL3 interrupt. 3387 3388Function : plat_ic_get_pending_interrupt_id() [mandatory] 3389~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 3390 3391:: 3392 3393 Argument : void 3394 Return : uint32_t 3395 3396This API returns the id of the highest priority pending interrupt at the 3397platform IC. ``INTR_ID_UNAVAILABLE`` is returned when there is no interrupt 3398pending. 3399 3400In the case of Arm standard platforms using GICv2, the *Highest Priority 3401Pending Interrupt Register* (``GICC_HPPIR``) is read to determine the id of the 3402pending interrupt. The id that is returned by API depends upon the value of 3403the id read from the interrupt controller as follows. 3404 3405#. id < 1022. id is returned as is. 3406#. id = 1022. The *Aliased Highest Priority Pending Interrupt Register* 3407 (``GICC_AHPPIR``) is read to determine the id of the non-secure interrupt. 3408 This id is returned by the API. 3409#. id = 1023. ``INTR_ID_UNAVAILABLE`` is returned. 3410 3411In the case of Arm standard platforms using GICv3, if the API is invoked from 3412EL3, the system register ``ICC_HPPIR0_EL1``, *Highest Priority Pending Interrupt 3413group 0 Register*, is read to determine the id of the pending interrupt. The id 3414that is returned by API depends upon the value of the id read from the 3415interrupt controller as follows. 3416 3417#. id < ``PENDING_G1S_INTID`` (1020). id is returned as is. 3418#. id = ``PENDING_G1S_INTID`` (1020) or ``PENDING_G1NS_INTID`` (1021). The system 3419 register ``ICC_HPPIR1_EL1``, *Highest Priority Pending Interrupt group 1 3420 Register* is read to determine the id of the group 1 interrupt. This id 3421 is returned by the API as long as it is a valid interrupt id 3422#. If the id is any of the special interrupt identifiers, 3423 ``INTR_ID_UNAVAILABLE`` is returned. 3424 3425When the API invoked from S-EL1 for GICv3 systems, the id read from system 3426register ``ICC_HPPIR1_EL1``, *Highest Priority Pending group 1 Interrupt 3427Register*, is returned if is not equal to GIC_SPURIOUS_INTERRUPT (1023) else 3428``INTR_ID_UNAVAILABLE`` is returned. 3429 3430Function : plat_ic_acknowledge_interrupt() [mandatory] 3431~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 3432 3433:: 3434 3435 Argument : void 3436 Return : uint32_t 3437 3438This API is used by the CPU to indicate to the platform IC that processing of 3439the highest pending interrupt has begun. It should return the raw, unmodified 3440value obtained from the interrupt controller when acknowledging an interrupt. 3441The actual interrupt number shall be extracted from this raw value using the API 3442`plat_ic_get_interrupt_id()<plat_ic_get_interrupt_id>`. 3443 3444This function in Arm standard platforms using GICv2, reads the *Interrupt 3445Acknowledge Register* (``GICC_IAR``). This changes the state of the highest 3446priority pending interrupt from pending to active in the interrupt controller. 3447It returns the value read from the ``GICC_IAR``, unmodified. 3448 3449In the case of Arm standard platforms using GICv3, if the API is invoked 3450from EL3, the function reads the system register ``ICC_IAR0_EL1``, *Interrupt 3451Acknowledge Register group 0*. If the API is invoked from S-EL1, the function 3452reads the system register ``ICC_IAR1_EL1``, *Interrupt Acknowledge Register 3453group 1*. The read changes the state of the highest pending interrupt from 3454pending to active in the interrupt controller. The value read is returned 3455unmodified. 3456 3457The TSP uses this API to start processing of the secure physical timer 3458interrupt. 3459 3460Function : plat_ic_end_of_interrupt() [mandatory] 3461~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 3462 3463:: 3464 3465 Argument : uint32_t 3466 Return : void 3467 3468This API is used by the CPU to indicate to the platform IC that processing of 3469the interrupt corresponding to the id (passed as the parameter) has 3470finished. The id should be the same as the id returned by the 3471``plat_ic_acknowledge_interrupt()`` API. 3472 3473Arm standard platforms write the id to the *End of Interrupt Register* 3474(``GICC_EOIR``) in case of GICv2, and to ``ICC_EOIR0_EL1`` or ``ICC_EOIR1_EL1`` 3475system register in case of GICv3 depending on where the API is invoked from, 3476EL3 or S-EL1. This deactivates the corresponding interrupt in the interrupt 3477controller. 3478 3479The TSP uses this API to finish processing of the secure physical timer 3480interrupt. 3481 3482Function : plat_ic_get_interrupt_type() [mandatory] 3483~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 3484 3485:: 3486 3487 Argument : uint32_t 3488 Return : uint32_t 3489 3490This API returns the type of the interrupt id passed as the parameter. 3491``INTR_TYPE_INVAL`` is returned if the id is invalid. If the id is valid, a valid 3492interrupt type (one of ``INTR_TYPE_EL3``, ``INTR_TYPE_S_EL1`` and ``INTR_TYPE_NS``) is 3493returned depending upon how the interrupt has been configured by the platform 3494IC. This API must be invoked at EL3. 3495 3496Arm standard platforms using GICv2 configures S-EL1 interrupts as Group0 interrupts 3497and Non-secure interrupts as Group1 interrupts. It reads the group value 3498corresponding to the interrupt id from the relevant *Interrupt Group Register* 3499(``GICD_IGROUPRn``). It uses the group value to determine the type of interrupt. 3500 3501In the case of Arm standard platforms using GICv3, both the *Interrupt Group 3502Register* (``GICD_IGROUPRn``) and *Interrupt Group Modifier Register* 3503(``GICD_IGRPMODRn``) is read to figure out whether the interrupt is configured 3504as Group 0 secure interrupt, Group 1 secure interrupt or Group 1 NS interrupt. 3505 3506Registering a console 3507--------------------- 3508 3509Platforms will need to implement the TF-A console framework to register and use 3510a console for visual data output in TF-A. These can be used for data output during 3511the different stages of the firmware boot process and also for debugging purposes. 3512 3513The console framework can be used to output data on to a console using a number of 3514TF-A supported UARTs. Multiple consoles can be registered at the same time with 3515different output scopes (BOOT, RUNTIME, CRASH) so that data can be displayed on 3516their respective consoles without unnecessary cluttering of a single console. 3517 3518Information for registering a console can be found in the :ref:`Console Framework` section 3519of the :ref:`System Design` documentation. 3520 3521Common helper functions 3522----------------------- 3523Function : elx_panic() 3524~~~~~~~~~~~~~~~~~~~~~~ 3525 3526:: 3527 3528 Argument : void 3529 Return : void 3530 3531This API is called from assembly files when reporting a critical failure 3532that has occured in lower EL and is been trapped in EL3. This call 3533**must not** return. 3534 3535Function : el3_panic() 3536~~~~~~~~~~~~~~~~~~~~~~ 3537 3538:: 3539 3540 Argument : void 3541 Return : void 3542 3543This API is called from assembly files when encountering a critical failure that 3544cannot be recovered from. This function assumes that it is invoked from a C 3545runtime environment i.e. valid stack exists. This call **must not** return. 3546 3547Function : panic() 3548~~~~~~~~~~~~~~~~~~ 3549 3550:: 3551 3552 Argument : void 3553 Return : void 3554 3555This API called from C files when encountering a critical failure that cannot 3556be recovered from. This function in turn prints backtrace (if enabled) and calls 3557el3_panic(). This call **must not** return. 3558 3559Crash Reporting mechanism (in BL31) 3560----------------------------------- 3561 3562BL31 implements a crash reporting mechanism which prints the various registers 3563of the CPU to enable quick crash analysis and debugging. This mechanism relies 3564on the platform implementing ``plat_crash_console_init``, 3565``plat_crash_console_putc`` and ``plat_crash_console_flush``. 3566 3567The file ``plat/common/aarch64/crash_console_helpers.S`` contains sample 3568implementation of all of them. Platforms may include this file to their 3569makefiles in order to benefit from them. By default, they will cause the crash 3570output to be routed over the normal console infrastructure and get printed on 3571consoles configured to output in crash state. ``console_set_scope()`` can be 3572used to control whether a console is used for crash output. 3573 3574.. note:: 3575 Platforms are responsible for making sure that they only mark consoles for 3576 use in the crash scope that are able to support this, i.e. that are written 3577 in assembly and conform with the register clobber rules for putc() 3578 (x0-x2, x16-x17) and flush() (x0-x3, x16-x17) crash callbacks. 3579 3580In some cases (such as debugging very early crashes that happen before the 3581normal boot console can be set up), platforms may want to control crash output 3582more explicitly. These platforms may instead provide custom implementations for 3583these. They are executed outside of a C environment and without a stack. Many 3584console drivers provide functions named ``console_xxx_core_init/putc/flush`` 3585that are designed to be used by these functions. See Arm platforms (like juno) 3586for an example of this. 3587 3588Function : plat_crash_console_init [mandatory] 3589~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 3590 3591:: 3592 3593 Argument : void 3594 Return : int 3595 3596This API is used by the crash reporting mechanism to initialize the crash 3597console. It must only use the general purpose registers x0 through x7 to do the 3598initialization and returns 1 on success. 3599 3600Function : plat_crash_console_putc [mandatory] 3601~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 3602 3603:: 3604 3605 Argument : int 3606 Return : int 3607 3608This API is used by the crash reporting mechanism to print a character on the 3609designated crash console. It must only use general purpose registers x1 and 3610x2 to do its work. The parameter and the return value are in general purpose 3611register x0. 3612 3613Function : plat_crash_console_flush [mandatory] 3614~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 3615 3616:: 3617 3618 Argument : void 3619 Return : void 3620 3621This API is used by the crash reporting mechanism to force write of all buffered 3622data on the designated crash console. It should only use general purpose 3623registers x0 through x5 to do its work. 3624 3625Function : plat_setup_early_console [optional] 3626~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 3627 3628:: 3629 3630 Argument : void 3631 Return : void 3632 3633This API is used to setup the early console, it is required only if the flag 3634``EARLY_CONSOLE`` is enabled. 3635 3636.. _External Abort handling and RAS Support: 3637 3638External Abort handling and RAS Support 3639--------------------------------------- 3640 3641If any cores on the platform support powerdown abandon (check the "Core powerup 3642and powerdown sequence" in their TRMs), then 3643these functions should be able to handle being called with power domains off and 3644after the powerdown ``wfi``. In other words it may run after a call to 3645``pwr_domain_suspend()`` and before a call to ``pwr_domain_suspend_finish()`` 3646(and their power off counterparts). 3647 3648Should this not be desirable, or if there is no powerdown abandon support, then 3649RAS errors should be masked by writing any relevant error records in any 3650powerdown hooks to prevent deadlocks due to a RAS error after the point of no 3651return. See the core's TRM for further information. 3652 3653Function : plat_ea_handler 3654~~~~~~~~~~~~~~~~~~~~~~~~~~ 3655 3656:: 3657 3658 Argument : int 3659 Argument : uint64_t 3660 Argument : void * 3661 Argument : void * 3662 Argument : uint64_t 3663 Return : void 3664 3665This function is invoked by the runtime exception handling framework for the 3666platform to handle an External Abort received at EL3. The intention of the 3667function is to attempt to resolve the cause of External Abort and return; 3668if that's not possible then an orderly shutdown of the system is initiated. 3669 3670The first parameter (``int ea_reason``) indicates the reason for External Abort. 3671Its value is one of ``ERROR_EA_*`` constants defined in ``ea_handle.h``. 3672 3673The second parameter (``uint64_t syndrome``) is the respective syndrome 3674presented to EL3 after having received the External Abort. Depending on the 3675nature of the abort (as can be inferred from the ``ea_reason`` parameter), this 3676can be the content of either ``ESR_EL3`` or ``DISR_EL1``. 3677 3678The third parameter (``void *cookie``) is unused for now. The fourth parameter 3679(``void *handle``) is a pointer to the preempted context. The fifth parameter 3680(``uint64_t flags``) indicates the preempted security state. These parameters 3681are received from the top-level exception handler. 3682 3683This function must be implemented if a platform expects Firmware First handling 3684of External Aborts. 3685 3686Function : plat_handle_uncontainable_ea 3687~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 3688 3689:: 3690 3691 Argument : int 3692 Argument : uint64_t 3693 Return : void 3694 3695This function is invoked by the RAS framework when an External Abort of 3696Uncontainable type is received at EL3. Due to the critical nature of 3697Uncontainable errors, the intention of this function is to initiate orderly 3698shutdown of the system, and is not expected to return. 3699 3700This function must be implemented in assembly. 3701 3702The first and second parameters are the same as that of ``plat_ea_handler``. 3703 3704The default implementation of this function calls 3705``report_unhandled_exception``. 3706 3707Function : plat_handle_double_fault 3708~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 3709 3710:: 3711 3712 Argument : int 3713 Argument : uint64_t 3714 Return : void 3715 3716This function is invoked by the RAS framework when another External Abort is 3717received at EL3 while one is already being handled. I.e., a call to 3718``plat_ea_handler`` is outstanding. Due to its critical nature, the intention of 3719this function is to initiate orderly shutdown of the system, and is not expected 3720recover or return. 3721 3722This function must be implemented in assembly. 3723 3724The first and second parameters are the same as that of ``plat_ea_handler``. 3725 3726The default implementation of this function calls 3727``report_unhandled_exception``. 3728 3729Function : plat_handle_el3_ea 3730~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 3731 3732:: 3733 3734 Return : void 3735 3736This function is invoked when an External Abort is received while executing in 3737EL3. Due to its critical nature, the intention of this function is to initiate 3738orderly shutdown of the system, and is not expected recover or return. 3739 3740This function must be implemented in assembly. 3741 3742The default implementation of this function calls 3743``report_unhandled_exception``. 3744 3745Function : plat_handle_rng_trap 3746~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 3747 3748:: 3749 3750 Argument : uint64_t 3751 Argument : cpu_context_t * 3752 Return : int 3753 3754This function is invoked by BL31's exception handler when there is a synchronous 3755system register trap caused by access to the RNDR or RNDRRS registers. It allows 3756platforms implementing ``FEAT_RNG_TRAP`` and enabling ``ENABLE_FEAT_RNG_TRAP`` to 3757emulate those system registers by returing back some entropy to the lower EL. 3758 3759The first parameter (``uint64_t esr_el3``) contains the content of the ESR_EL3 3760syndrome register, which encodes the instruction that was trapped. The interesting 3761information in there is the target register (``get_sysreg_iss_rt()``). 3762 3763The second parameter (``cpu_context_t *ctx``) represents the CPU state in the 3764lower exception level, at the time when the execution of the ``mrs`` instruction 3765was trapped. Its content can be changed, to put the entropy into the target 3766register. 3767 3768The return value indicates how to proceed: 3769 3770- When returning ``TRAP_RET_UNHANDLED`` (-1), the machine will panic. 3771- When returning ``TRAP_RET_REPEAT`` (0), the exception handler will return 3772 to the same instruction, so its execution will be repeated. 3773- When returning ``TRAP_RET_CONTINUE`` (1), the exception handler will return 3774 to the next instruction. 3775 3776This function needs to be implemented by a platform if it enables FEAT_RNG_TRAP. 3777 3778Function : plat_handle_impdef_trap 3779~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 3780 3781:: 3782 3783 Argument : uint64_t 3784 Argument : cpu_context_t * 3785 Return : int 3786 3787This function is invoked by BL31's exception handler when there is a synchronous 3788system register trap caused by access to the implementation defined registers. 3789It allows platforms enabling ``IMPDEF_SYSREG_TRAP`` to emulate those system 3790registers choosing to program bits of their choice. If using in combination with 3791``ARCH_FEATURE_AVAILABILITY``, the macros 3792{SCR,MDCR,CPTR}_PLAT_{BITS,IGNORED,FLIPPED} should be defined to report correct 3793results. 3794 3795The first parameter (``uint64_t esr_el3``) contains the content of the ESR_EL3 3796syndrome register, which encodes the instruction that was trapped. 3797 3798The second parameter (``cpu_context_t *ctx``) represents the CPU state in the 3799lower exception level, at the time when the execution of the ``mrs`` instruction 3800was trapped. 3801 3802The return value indicates how to proceed: 3803 3804- When returning ``TRAP_RET_UNHANDLED`` (-1), the machine will panic. 3805- When returning ``TRAP_RET_REPEAT`` (0), the exception handler will return 3806 to the same instruction, so its execution will be repeated. 3807- When returning ``TRAP_RET_CONTINUE`` (1), the exception handler will return 3808 to the next instruction. 3809 3810This function needs to be implemented by a platform if it enables 3811IMPDEF_SYSREG_TRAP. 3812 3813Build flags 3814----------- 3815 3816There are some build flags which can be defined by the platform to control 3817inclusion or exclusion of certain BL stages from the FIP image. These flags 3818need to be defined in the platform makefile which will get included by the 3819build system. 3820 3821- **NEED_BL33** 3822 By default, this flag is defined ``yes`` by the build system and ``BL33`` 3823 build option should be supplied as a build option. The platform has the 3824 option of excluding the BL33 image in the ``fip`` image by defining this flag 3825 to ``no``. If any of the options ``EL3_PAYLOAD_BASE`` or ``PRELOADED_BL33_BASE`` 3826 are used, this flag will be set to ``no`` automatically. 3827 3828- **ARM_ARCH_MAJOR and ARM_ARCH_MINOR** 3829 By default, ARM_ARCH_MAJOR.ARM_ARCH_MINOR is set to 8.0 in ``defaults.mk``, 3830 if the platform makefile/build defines or uses the correct ARM_ARCH_MAJOR and 3831 ARM_ARCH_MINOR then mandatory Architectural features available for that Arch 3832 version will be enabled by default and any optional Arch feature supported by 3833 the Architecture and available in TF-A can be enabled from platform specific 3834 makefile. Look up to ``arch_features.mk`` for details pertaining to mandatory 3835 and optional Arch specific features. 3836 3837Platform include paths 3838---------------------- 3839 3840Platforms are allowed to add more include paths to be passed to the compiler. 3841The ``PLAT_INCLUDES`` variable is used for this purpose. This is needed in 3842particular for the file ``platform_def.h``. 3843 3844Example: 3845 3846.. code:: c 3847 3848 PLAT_INCLUDES += -Iinclude/plat/myplat/include 3849 3850C Library 3851--------- 3852 3853To avoid subtle toolchain behavioral dependencies, the header files provided 3854by the compiler are not used. The software is built with the ``-nostdinc`` flag 3855to ensure no headers are included from the toolchain inadvertently. Instead the 3856required headers are included in the TF-A source tree. The library only 3857contains those C library definitions required by the local implementation. If 3858more functionality is required, the needed library functions will need to be 3859added to the local implementation. 3860 3861Some C headers have been obtained from `FreeBSD`_ and `SCC`_, while others have 3862been written specifically for TF-A. Some implementation files have been obtained 3863from `FreeBSD`_, others have been written specifically for TF-A as well. The 3864files can be found in ``include/lib/libc`` and ``lib/libc``. 3865 3866SCC can be found in http://www.simple-cc.org/. A copy of the `FreeBSD`_ sources 3867can be obtained from http://github.com/freebsd/freebsd. 3868 3869Storage abstraction layer 3870------------------------- 3871 3872In order to improve platform independence and portability a storage abstraction 3873layer is used to load data from non-volatile platform storage. Currently 3874storage access is only required by BL1 and BL2 phases and performed inside the 3875``load_image()`` function in ``bl_common.c``. 3876 3877.. uml:: resources/diagrams/plantuml/io_framework_usage_overview.puml 3878 3879It is mandatory to implement at least one storage driver. For the Arm 3880development platforms the Firmware Image Package (FIP) driver is provided as 3881the default means to load data from storage (see :ref:`firmware_design_fip`). 3882The storage layer is described in the header file 3883``include/drivers/io/io_storage.h``. The implementation of the common library is 3884in ``drivers/io/io_storage.c`` and the driver files are located in 3885``drivers/io/``. 3886 3887.. uml:: resources/diagrams/plantuml/io_arm_class_diagram.puml 3888 3889Each IO driver must provide ``io_dev_*`` structures, as described in 3890``drivers/io/io_driver.h``. These are returned via a mandatory registration 3891function that is called on platform initialization. The semi-hosting driver 3892implementation in ``io_semihosting.c`` can be used as an example. 3893 3894Each platform should register devices and their drivers via the storage 3895abstraction layer. These drivers then need to be initialized by bootloader 3896phases as required in their respective ``blx_platform_setup()`` functions. 3897 3898.. uml:: resources/diagrams/plantuml/io_dev_registration.puml 3899 3900The storage abstraction layer provides mechanisms (``io_dev_init()``) to 3901initialize storage devices before IO operations are called. 3902 3903.. uml:: resources/diagrams/plantuml/io_dev_init_and_check.puml 3904 3905The basic operations supported by the layer 3906include ``open()``, ``close()``, ``read()``, ``write()``, ``size()`` and ``seek()``. 3907Drivers do not have to implement all operations, but each platform must 3908provide at least one driver for a device capable of supporting generic 3909operations such as loading a bootloader image. 3910 3911The current implementation only allows for known images to be loaded by the 3912firmware. These images are specified by using their identifiers, as defined in 3913``include/plat/common/common_def.h`` (or a separate header file included from 3914there). The platform layer (``plat_get_image_source()``) then returns a reference 3915to a device and a driver-specific ``spec`` which will be understood by the driver 3916to allow access to the image data. 3917 3918The layer is designed in such a way that is it possible to chain drivers with 3919other drivers. For example, file-system drivers may be implemented on top of 3920physical block devices, both represented by IO devices with corresponding 3921drivers. In such a case, the file-system "binding" with the block device may 3922be deferred until the file-system device is initialised. 3923 3924The abstraction currently depends on structures being statically allocated 3925by the drivers and callers, as the system does not yet provide a means of 3926dynamically allocating memory. This may also have the affect of limiting the 3927amount of open resources per driver. 3928 3929Measured Boot Platform Interface 3930-------------------------------- 3931 3932Enabling the MEASURED_BOOT flag adds extra platform requirements. Please refer 3933to :ref:`Measured Boot Design` for more details. 3934 3935Live Firmware Activation Interface 3936---------------------------------- 3937 3938Function : plat_lfa_get_components() 3939~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 3940 3941:: 3942 3943 Argument : plat_lfa_component_info_t ** 3944 Return : int 3945 3946This platform API provides the list of LFA components available for activation. 3947It populates a pointer to an array of ``plat_lfa_component_info_t`` structures, 3948which contain information about each component (like UUID, ID, etc.). It returns 39490 on success, or a standard error code on failure. 3950 3951Function : is_plat_lfa_activation_pending() 3952~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 3953 3954:: 3955 3956 Argument : uint32_t 3957 Return : bool 3958 3959This platform API checks if the specified LFA component, identified 3960by its ``lfa_component_id``, is available for activation. It returns 3961true if available, otherwise false. 3962 3963Function : plat_lfa_cancel() 3964~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 3965 3966:: 3967 3968 Argument : uint32_t 3969 Return : int 3970 3971This platform API allows the platform to cancel an ongoing update or activation 3972process for the specified ``lfa_component_id``. It returns 0 on success or 3973a standard error code on failure. 3974 3975Function : plat_lfa_load_auth_image() 3976~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 3977 3978:: 3979 3980 Argument : uint32_t 3981 Return : int 3982 3983The platform uses this API to load, authenticate and measure the component 3984specified by ``lfa_component_id``. It should return 0 on success or appropriate 3985error codes for load/authentication failures. 3986 3987-------------- 3988 3989*Copyright (c) 2013-2025, Arm Limited and Contributors. All rights reserved.* 3990 3991.. _PSCI: https://developer.arm.com/documentation/den0022/latest/ 3992.. _Arm Generic Interrupt Controller version 2.0 (GICv2): http://infocenter.arm.com/help/topic/com.arm.doc.ihi0048b/index.html 3993.. _3.0 (GICv3): http://infocenter.arm.com/help/topic/com.arm.doc.ihi0069b/index.html 3994.. _FreeBSD: https://www.freebsd.org 3995.. _SCC: http://www.simple-cc.org/ 3996.. _DRTM: https://developer.arm.com/documentation/den0113/a 3997