1 /* 2 * Copyright (c) 2016-2020, ARM Limited and Contributors. All rights reserved. 3 * 4 * SPDX-License-Identifier: BSD-3-Clause 5 */ 6 7 /* 8 * Contains generic routines to fix up the device tree blob passed on to 9 * payloads like BL32 and BL33 (and further down the boot chain). 10 * This allows to easily add PSCI nodes, when the original DT does not have 11 * it or advertises another method. 12 * Also it supports to add reserved memory nodes to describe memory that 13 * is used by the secure world, so that non-secure software avoids using 14 * that. 15 */ 16 17 #include <errno.h> 18 #include <stdio.h> 19 #include <string.h> 20 21 #include <libfdt.h> 22 23 #include <arch.h> 24 #include <common/debug.h> 25 #include <common/fdt_fixup.h> 26 #include <common/fdt_wrappers.h> 27 #include <drivers/console.h> 28 #include <lib/psci/psci.h> 29 #include <plat/common/platform.h> 30 31 32 static int append_psci_compatible(void *fdt, int offs, const char *str) 33 { 34 return fdt_appendprop(fdt, offs, "compatible", str, strlen(str) + 1); 35 } 36 37 /* 38 * Those defines are for PSCI v0.1 legacy clients, which we expect to use 39 * the same execution state (AArch32/AArch64) as TF-A. 40 * Kernels running in AArch32 on an AArch64 TF-A should use PSCI v0.2. 41 */ 42 #ifdef __aarch64__ 43 #define PSCI_CPU_SUSPEND_FNID PSCI_CPU_SUSPEND_AARCH64 44 #define PSCI_CPU_ON_FNID PSCI_CPU_ON_AARCH64 45 #else 46 #define PSCI_CPU_SUSPEND_FNID PSCI_CPU_SUSPEND_AARCH32 47 #define PSCI_CPU_ON_FNID PSCI_CPU_ON_AARCH32 48 #endif 49 50 /******************************************************************************* 51 * dt_add_psci_node() - Add a PSCI node into an existing device tree 52 * @fdt: pointer to the device tree blob in memory 53 * 54 * Add a device tree node describing PSCI into the root level of an existing 55 * device tree blob in memory. 56 * This will add v0.1, v0.2 and v1.0 compatible strings and the standard 57 * function IDs for v0.1 compatibility. 58 * An existing PSCI node will not be touched, the function will return success 59 * in this case. This function will not touch the /cpus enable methods, use 60 * dt_add_psci_cpu_enable_methods() for that. 61 * 62 * Return: 0 on success, -1 otherwise. 63 ******************************************************************************/ 64 int dt_add_psci_node(void *fdt) 65 { 66 int offs; 67 68 if (fdt_path_offset(fdt, "/psci") >= 0) { 69 WARN("PSCI Device Tree node already exists!\n"); 70 return 0; 71 } 72 73 offs = fdt_path_offset(fdt, "/"); 74 if (offs < 0) 75 return -1; 76 offs = fdt_add_subnode(fdt, offs, "psci"); 77 if (offs < 0) 78 return -1; 79 if (append_psci_compatible(fdt, offs, "arm,psci-1.0")) 80 return -1; 81 if (append_psci_compatible(fdt, offs, "arm,psci-0.2")) 82 return -1; 83 if (append_psci_compatible(fdt, offs, "arm,psci")) 84 return -1; 85 if (fdt_setprop_string(fdt, offs, "method", "smc")) 86 return -1; 87 if (fdt_setprop_u32(fdt, offs, "cpu_suspend", PSCI_CPU_SUSPEND_FNID)) 88 return -1; 89 if (fdt_setprop_u32(fdt, offs, "cpu_off", PSCI_CPU_OFF)) 90 return -1; 91 if (fdt_setprop_u32(fdt, offs, "cpu_on", PSCI_CPU_ON_FNID)) 92 return -1; 93 return 0; 94 } 95 96 /* 97 * Find the first subnode that has a "device_type" property with the value 98 * "cpu" and which's enable-method is not "psci" (yet). 99 * Returns 0 if no such subnode is found, so all have already been patched 100 * or none have to be patched in the first place. 101 * Returns 1 if *one* such subnode has been found and successfully changed 102 * to "psci". 103 * Returns negative values on error. 104 * 105 * Call in a loop until it returns 0. Recalculate the node offset after 106 * it has returned 1. 107 */ 108 static int dt_update_one_cpu_node(void *fdt, int offset) 109 { 110 int offs; 111 112 /* Iterate over all subnodes to find those with device_type = "cpu". */ 113 for (offs = fdt_first_subnode(fdt, offset); offs >= 0; 114 offs = fdt_next_subnode(fdt, offs)) { 115 const char *prop; 116 int len; 117 int ret; 118 119 prop = fdt_getprop(fdt, offs, "device_type", &len); 120 if (prop == NULL) 121 continue; 122 if ((strcmp(prop, "cpu") != 0) || (len != 4)) 123 continue; 124 125 /* Ignore any nodes which already use "psci". */ 126 prop = fdt_getprop(fdt, offs, "enable-method", &len); 127 if ((prop != NULL) && 128 (strcmp(prop, "psci") == 0) && (len == 5)) 129 continue; 130 131 ret = fdt_setprop_string(fdt, offs, "enable-method", "psci"); 132 if (ret < 0) 133 return ret; 134 /* 135 * Subnode found and patched. 136 * Restart to accommodate potentially changed offsets. 137 */ 138 return 1; 139 } 140 141 if (offs == -FDT_ERR_NOTFOUND) 142 return 0; 143 144 return offs; 145 } 146 147 /******************************************************************************* 148 * dt_add_psci_cpu_enable_methods() - switch CPU nodes in DT to use PSCI 149 * @fdt: pointer to the device tree blob in memory 150 * 151 * Iterate over all CPU device tree nodes (/cpus/cpu@x) in memory to change 152 * the enable-method to PSCI. This will add the enable-method properties, if 153 * required, or will change existing properties to read "psci". 154 * 155 * Return: 0 on success, or a negative error value otherwise. 156 ******************************************************************************/ 157 158 int dt_add_psci_cpu_enable_methods(void *fdt) 159 { 160 int offs, ret; 161 162 do { 163 offs = fdt_path_offset(fdt, "/cpus"); 164 if (offs < 0) 165 return offs; 166 167 ret = dt_update_one_cpu_node(fdt, offs); 168 } while (ret > 0); 169 170 return ret; 171 } 172 173 #define HIGH_BITS(x) ((sizeof(x) > 4) ? ((x) >> 32) : (typeof(x))0) 174 175 /******************************************************************************* 176 * fdt_add_reserved_memory() - reserve (secure) memory regions in DT 177 * @dtb: pointer to the device tree blob in memory 178 * @node_name: name of the subnode to be used 179 * @base: physical base address of the reserved region 180 * @size: size of the reserved region 181 * 182 * Add a region of memory to the /reserved-memory node in a device tree in 183 * memory, creating that node if required. Each region goes into a subnode 184 * of that node and has a @node_name, a @base address and a @size. 185 * This will prevent any device tree consumer from using that memory. It 186 * can be used to announce secure memory regions, as it adds the "no-map" 187 * property to prevent mapping and speculative operations on that region. 188 * 189 * See reserved-memory/reserved-memory.txt in the (Linux kernel) DT binding 190 * documentation for details. 191 * 192 * Return: 0 on success, a negative error value otherwise. 193 ******************************************************************************/ 194 int fdt_add_reserved_memory(void *dtb, const char *node_name, 195 uintptr_t base, size_t size) 196 { 197 int offs = fdt_path_offset(dtb, "/reserved-memory"); 198 uint32_t addresses[3]; 199 200 if (offs < 0) { /* create if not existing yet */ 201 offs = fdt_add_subnode(dtb, 0, "reserved-memory"); 202 if (offs < 0) 203 return offs; 204 fdt_setprop_u32(dtb, offs, "#address-cells", 2); 205 fdt_setprop_u32(dtb, offs, "#size-cells", 1); 206 fdt_setprop(dtb, offs, "ranges", NULL, 0); 207 } 208 209 addresses[0] = cpu_to_fdt32(HIGH_BITS(base)); 210 addresses[1] = cpu_to_fdt32(base & 0xffffffff); 211 addresses[2] = cpu_to_fdt32(size & 0xffffffff); 212 offs = fdt_add_subnode(dtb, offs, node_name); 213 fdt_setprop(dtb, offs, "no-map", NULL, 0); 214 fdt_setprop(dtb, offs, "reg", addresses, 12); 215 216 return 0; 217 } 218 219 /******************************************************************************* 220 * fdt_add_cpu() Add a new CPU node to the DT 221 * @dtb: Pointer to the device tree blob in memory 222 * @parent: Offset of the parent node 223 * @mpidr: MPIDR for the current CPU 224 * 225 * Create and add a new cpu node to a DTB. 226 * 227 * Return the offset of the new node or a negative value in case of error 228 ******************************************************************************/ 229 230 static int fdt_add_cpu(void *dtb, int parent, u_register_t mpidr) 231 { 232 int cpu_offs; 233 int err; 234 char snode_name[15]; 235 uint64_t reg_prop; 236 237 reg_prop = mpidr & MPID_MASK & ~MPIDR_MT_MASK; 238 239 snprintf(snode_name, sizeof(snode_name), "cpu@%x", 240 (unsigned int)reg_prop); 241 242 cpu_offs = fdt_add_subnode(dtb, parent, snode_name); 243 if (cpu_offs < 0) { 244 ERROR ("FDT: add subnode \"%s\" failed: %i\n", 245 snode_name, cpu_offs); 246 return cpu_offs; 247 } 248 249 err = fdt_setprop_string(dtb, cpu_offs, "compatible", "arm,armv8"); 250 if (err < 0) { 251 ERROR ("FDT: write to \"%s\" property of node at offset %i failed\n", 252 "compatible", cpu_offs); 253 return err; 254 } 255 256 err = fdt_setprop_u64(dtb, cpu_offs, "reg", reg_prop); 257 if (err < 0) { 258 ERROR ("FDT: write to \"%s\" property of node at offset %i failed\n", 259 "reg", cpu_offs); 260 return err; 261 } 262 263 err = fdt_setprop_string(dtb, cpu_offs, "device_type", "cpu"); 264 if (err < 0) { 265 ERROR ("FDT: write to \"%s\" property of node at offset %i failed\n", 266 "device_type", cpu_offs); 267 return err; 268 } 269 270 err = fdt_setprop_string(dtb, cpu_offs, "enable-method", "psci"); 271 if (err < 0) { 272 ERROR ("FDT: write to \"%s\" property of node at offset %i failed\n", 273 "enable-method", cpu_offs); 274 return err; 275 } 276 277 return cpu_offs; 278 } 279 280 /****************************************************************************** 281 * fdt_add_cpus_node() - Add the cpus node to the DTB 282 * @dtb: pointer to the device tree blob in memory 283 * @afflv0: Maximum number of threads per core (affinity level 0). 284 * @afflv1: Maximum number of CPUs per cluster (affinity level 1). 285 * @afflv2: Maximum number of clusters (affinity level 2). 286 * 287 * Iterate over all the possible MPIDs given the maximum affinity levels and 288 * add a cpus node to the DTB with all the valid CPUs on the system. 289 * If there is already a /cpus node, exit gracefully 290 * 291 * A system with two CPUs would generate a node equivalent or similar to: 292 * 293 * cpus { 294 * #address-cells = <2>; 295 * #size-cells = <0>; 296 * 297 * cpu0: cpu@0 { 298 * compatible = "arm,armv8"; 299 * reg = <0x0 0x0>; 300 * device_type = "cpu"; 301 * enable-method = "psci"; 302 * }; 303 * cpu1: cpu@10000 { 304 * compatible = "arm,armv8"; 305 * reg = <0x0 0x100>; 306 * device_type = "cpu"; 307 * enable-method = "psci"; 308 * }; 309 * }; 310 * 311 * Full documentation about the CPU bindings can be found at: 312 * https://www.kernel.org/doc/Documentation/devicetree/bindings/arm/cpus.txt 313 * 314 * Return the offset of the node or a negative value on error. 315 ******************************************************************************/ 316 317 int fdt_add_cpus_node(void *dtb, unsigned int afflv0, 318 unsigned int afflv1, unsigned int afflv2) 319 { 320 int offs; 321 int err; 322 unsigned int i, j, k; 323 u_register_t mpidr; 324 int cpuid; 325 326 if (fdt_path_offset(dtb, "/cpus") >= 0) { 327 return -EEXIST; 328 } 329 330 offs = fdt_add_subnode(dtb, 0, "cpus"); 331 if (offs < 0) { 332 ERROR ("FDT: add subnode \"cpus\" node to parent node failed"); 333 return offs; 334 } 335 336 err = fdt_setprop_u32(dtb, offs, "#address-cells", 2); 337 if (err < 0) { 338 ERROR ("FDT: write to \"%s\" property of node at offset %i failed\n", 339 "#address-cells", offs); 340 return err; 341 } 342 343 err = fdt_setprop_u32(dtb, offs, "#size-cells", 0); 344 if (err < 0) { 345 ERROR ("FDT: write to \"%s\" property of node at offset %i failed\n", 346 "#size-cells", offs); 347 return err; 348 } 349 350 /* 351 * Populate the node with the CPUs. 352 * As libfdt prepends subnodes within a node, reverse the index count 353 * so the CPU nodes would be better ordered. 354 */ 355 for (i = afflv2; i > 0U; i--) { 356 for (j = afflv1; j > 0U; j--) { 357 for (k = afflv0; k > 0U; k--) { 358 mpidr = ((i - 1) << MPIDR_AFF2_SHIFT) | 359 ((j - 1) << MPIDR_AFF1_SHIFT) | 360 ((k - 1) << MPIDR_AFF0_SHIFT) | 361 (read_mpidr_el1() & MPIDR_MT_MASK); 362 363 cpuid = plat_core_pos_by_mpidr(mpidr); 364 if (cpuid >= 0) { 365 /* Valid MPID found */ 366 err = fdt_add_cpu(dtb, offs, mpidr); 367 if (err < 0) { 368 ERROR ("FDT: %s 0x%08x\n", 369 "error adding CPU", 370 (uint32_t)mpidr); 371 return err; 372 } 373 } 374 } 375 } 376 } 377 378 return offs; 379 } 380