1/* 2 * armboot - Startup Code for ARM920 CPU-core 3 * 4 * Copyright (c) 2001 Marius Gröger <mag@sysgo.de> 5 * Copyright (c) 2002 Alex Züpke <azu@sysgo.de> 6 * Copyright (c) 2002 Gary Jennejohn <garyj@denx.de> 7 * 8 * See file CREDITS for list of people who contributed to this 9 * project. 10 * 11 * This program is free software; you can redistribute it and/or 12 * modify it under the terms of the GNU General Public License as 13 * published by the Free Software Foundation; either version 2 of 14 * the License, or (at your option) any later version. 15 * 16 * This program is distributed in the hope that it will be useful, 17 * but WITHOUT ANY WARRANTY; without even the implied warranty of 18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 19 * GNU General Public License for more details. 20 * 21 * You should have received a copy of the GNU General Public License 22 * along with this program; if not, write to the Free Software 23 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, 24 * MA 02111-1307 USA 25 */ 26 27#include <asm-offsets.h> 28#include <common.h> 29#include <config.h> 30 31/* 32 ************************************************************************* 33 * 34 * Jump vector table as in table 3.1 in [1] 35 * 36 ************************************************************************* 37 */ 38 39 40.globl _start 41_start: b start_code 42 ldr pc, _undefined_instruction 43 ldr pc, _software_interrupt 44 ldr pc, _prefetch_abort 45 ldr pc, _data_abort 46 ldr pc, _not_used 47 ldr pc, _irq 48 ldr pc, _fiq 49 50_undefined_instruction: .word undefined_instruction 51_software_interrupt: .word software_interrupt 52_prefetch_abort: .word prefetch_abort 53_data_abort: .word data_abort 54_not_used: .word not_used 55_irq: .word irq 56_fiq: .word fiq 57 58 .balignl 16,0xdeadbeef 59 60 61/* 62 ************************************************************************* 63 * 64 * Startup Code (called from the ARM reset exception vector) 65 * 66 * do important init only if we don't start from memory! 67 * relocate armboot to ram 68 * setup stack 69 * jump to second stage 70 * 71 ************************************************************************* 72 */ 73 74.globl _TEXT_BASE 75_TEXT_BASE: 76#if defined(CONFIG_SPL_BUILD) && defined(CONFIG_SPL_TEXT_BASE) 77 .word CONFIG_SPL_TEXT_BASE 78#else 79 .word CONFIG_SYS_TEXT_BASE 80#endif 81 82/* 83 * These are defined in the board-specific linker script. 84 * Subtracting _start from them lets the linker put their 85 * relative position in the executable instead of leaving 86 * them null. 87 */ 88.globl _bss_start_ofs 89_bss_start_ofs: 90 .word __bss_start - _start 91 92.globl _bss_end_ofs 93_bss_end_ofs: 94 .word __bss_end - _start 95 96.globl _end_ofs 97_end_ofs: 98 .word _end - _start 99 100#ifdef CONFIG_USE_IRQ 101/* IRQ stack memory (calculated at run-time) */ 102.globl IRQ_STACK_START 103IRQ_STACK_START: 104 .word 0x0badc0de 105 106/* IRQ stack memory (calculated at run-time) */ 107.globl FIQ_STACK_START 108FIQ_STACK_START: 109 .word 0x0badc0de 110#endif 111 112/* IRQ stack memory (calculated at run-time) + 8 bytes */ 113.globl IRQ_STACK_START_IN 114IRQ_STACK_START_IN: 115 .word 0x0badc0de 116 117/* 118 * the actual start code 119 */ 120 121start_code: 122 /* 123 * set the cpu to SVC32 mode 124 */ 125 mrs r0, cpsr 126 bic r0, r0, #0x1f 127 orr r0, r0, #0xd3 128 msr cpsr, r0 129 130#if defined(CONFIG_AT91RM9200DK) || defined(CONFIG_AT91RM9200EK) 131 /* 132 * relocate exception table 133 */ 134 ldr r0, =_start 135 ldr r1, =0x0 136 mov r2, #16 137copyex: 138 subs r2, r2, #1 139 ldr r3, [r0], #4 140 str r3, [r1], #4 141 bne copyex 142#endif 143 144#ifdef CONFIG_S3C24X0 145 /* turn off the watchdog */ 146 147# if defined(CONFIG_S3C2400) 148# define pWTCON 0x15300000 149# define INTMSK 0x14400008 /* Interrupt-Controller base addresses */ 150# define CLKDIVN 0x14800014 /* clock divisor register */ 151#else 152# define pWTCON 0x53000000 153# define INTMSK 0x4A000008 /* Interrupt-Controller base addresses */ 154# define INTSUBMSK 0x4A00001C 155# define CLKDIVN 0x4C000014 /* clock divisor register */ 156# endif 157 158 ldr r0, =pWTCON 159 mov r1, #0x0 160 str r1, [r0] 161 162 /* 163 * mask all IRQs by setting all bits in the INTMR - default 164 */ 165 mov r1, #0xffffffff 166 ldr r0, =INTMSK 167 str r1, [r0] 168# if defined(CONFIG_S3C2410) 169 ldr r1, =0x3ff 170 ldr r0, =INTSUBMSK 171 str r1, [r0] 172# endif 173 174 /* FCLK:HCLK:PCLK = 1:2:4 */ 175 /* default FCLK is 120 MHz ! */ 176 ldr r0, =CLKDIVN 177 mov r1, #3 178 str r1, [r0] 179#endif /* CONFIG_S3C24X0 */ 180 181 /* 182 * we do sys-critical inits only at reboot, 183 * not when booting from ram! 184 */ 185#ifndef CONFIG_SKIP_LOWLEVEL_INIT 186 bl cpu_init_crit 187#endif 188 189 bl _main 190 191/*------------------------------------------------------------------------------*/ 192 193#ifndef CONFIG_SPL_BUILD 194/* 195 * void relocate_code(addr_moni) 196 * 197 * This function relocates the monitor code. 198 */ 199 .globl relocate_code 200relocate_code: 201 mov r6, r0 /* save addr of destination */ 202 203 adr r0, _start 204 subs r9, r6, r0 /* r9 <- relocation offset */ 205 beq relocate_done /* skip relocation */ 206 mov r1, r6 /* r1 <- scratch for copy_loop */ 207 ldr r3, _image_copy_end_ofs 208 add r2, r0, r3 /* r2 <- source end address */ 209 210copy_loop: 211 ldmia r0!, {r10-r11} /* copy from source address [r0] */ 212 stmia r1!, {r10-r11} /* copy to target address [r1] */ 213 cmp r0, r2 /* until source end address [r2] */ 214 blo copy_loop 215 216 /* 217 * fix .rel.dyn relocations 218 */ 219 ldr r0, _TEXT_BASE /* r0 <- Text base */ 220 ldr r10, _dynsym_start_ofs /* r10 <- sym table ofs */ 221 add r10, r10, r0 /* r10 <- sym table in FLASH */ 222 ldr r2, _rel_dyn_start_ofs /* r2 <- rel dyn start ofs */ 223 add r2, r2, r0 /* r2 <- rel dyn start in FLASH */ 224 ldr r3, _rel_dyn_end_ofs /* r3 <- rel dyn end ofs */ 225 add r3, r3, r0 /* r3 <- rel dyn end in FLASH */ 226fixloop: 227 ldr r0, [r2] /* r0 <- location to fix up, IN FLASH! */ 228 add r0, r0, r9 /* r0 <- location to fix up in RAM */ 229 ldr r1, [r2, #4] 230 and r7, r1, #0xff 231 cmp r7, #23 /* relative fixup? */ 232 beq fixrel 233 cmp r7, #2 /* absolute fixup? */ 234 beq fixabs 235 /* ignore unknown type of fixup */ 236 b fixnext 237fixabs: 238 /* absolute fix: set location to (offset) symbol value */ 239 mov r1, r1, LSR #4 /* r1 <- symbol index in .dynsym */ 240 add r1, r10, r1 /* r1 <- address of symbol in table */ 241 ldr r1, [r1, #4] /* r1 <- symbol value */ 242 add r1, r1, r9 /* r1 <- relocated sym addr */ 243 b fixnext 244fixrel: 245 /* relative fix: increase location by offset */ 246 ldr r1, [r0] 247 add r1, r1, r9 248fixnext: 249 str r1, [r0] 250 add r2, r2, #8 /* each rel.dyn entry is 8 bytes */ 251 cmp r2, r3 252 blo fixloop 253relocate_done: 254 255 mov pc, lr 256 257_image_copy_end_ofs: 258 .word __image_copy_end - _start 259_rel_dyn_start_ofs: 260 .word __rel_dyn_start - _start 261_rel_dyn_end_ofs: 262 .word __rel_dyn_end - _start 263_dynsym_start_ofs: 264 .word __dynsym_start - _start 265 266#endif 267 268 .globl c_runtime_cpu_setup 269c_runtime_cpu_setup: 270 271 mov pc, lr 272 273/* 274 ************************************************************************* 275 * 276 * CPU_init_critical registers 277 * 278 * setup important registers 279 * setup memory timing 280 * 281 ************************************************************************* 282 */ 283 284 285#ifndef CONFIG_SKIP_LOWLEVEL_INIT 286cpu_init_crit: 287 /* 288 * flush v4 I/D caches 289 */ 290 mov r0, #0 291 mcr p15, 0, r0, c7, c7, 0 /* flush v3/v4 cache */ 292 mcr p15, 0, r0, c8, c7, 0 /* flush v4 TLB */ 293 294 /* 295 * disable MMU stuff and caches 296 */ 297 mrc p15, 0, r0, c1, c0, 0 298 bic r0, r0, #0x00002300 @ clear bits 13, 9:8 (--V- --RS) 299 bic r0, r0, #0x00000087 @ clear bits 7, 2:0 (B--- -CAM) 300 orr r0, r0, #0x00000002 @ set bit 2 (A) Align 301 orr r0, r0, #0x00001000 @ set bit 12 (I) I-Cache 302 mcr p15, 0, r0, c1, c0, 0 303 304 /* 305 * before relocating, we have to setup RAM timing 306 * because memory timing is board-dependend, you will 307 * find a lowlevel_init.S in your board directory. 308 */ 309 mov ip, lr 310 311 bl lowlevel_init 312 313 mov lr, ip 314 mov pc, lr 315#endif /* CONFIG_SKIP_LOWLEVEL_INIT */ 316 317/* 318 ************************************************************************* 319 * 320 * Interrupt handling 321 * 322 ************************************************************************* 323 */ 324 325@ 326@ IRQ stack frame. 327@ 328#define S_FRAME_SIZE 72 329 330#define S_OLD_R0 68 331#define S_PSR 64 332#define S_PC 60 333#define S_LR 56 334#define S_SP 52 335 336#define S_IP 48 337#define S_FP 44 338#define S_R10 40 339#define S_R9 36 340#define S_R8 32 341#define S_R7 28 342#define S_R6 24 343#define S_R5 20 344#define S_R4 16 345#define S_R3 12 346#define S_R2 8 347#define S_R1 4 348#define S_R0 0 349 350#define MODE_SVC 0x13 351#define I_BIT 0x80 352 353/* 354 * use bad_save_user_regs for abort/prefetch/undef/swi ... 355 * use irq_save_user_regs / irq_restore_user_regs for IRQ/FIQ handling 356 */ 357 358 .macro bad_save_user_regs 359 sub sp, sp, #S_FRAME_SIZE 360 stmia sp, {r0 - r12} @ Calling r0-r12 361 ldr r2, IRQ_STACK_START_IN 362 ldmia r2, {r2 - r3} @ get pc, cpsr 363 add r0, sp, #S_FRAME_SIZE @ restore sp_SVC 364 365 add r5, sp, #S_SP 366 mov r1, lr 367 stmia r5, {r0 - r3} @ save sp_SVC, lr_SVC, pc, cpsr 368 mov r0, sp 369 .endm 370 371 .macro irq_save_user_regs 372 sub sp, sp, #S_FRAME_SIZE 373 stmia sp, {r0 - r12} @ Calling r0-r12 374 add r7, sp, #S_PC 375 stmdb r7, {sp, lr}^ @ Calling SP, LR 376 str lr, [r7, #0] @ Save calling PC 377 mrs r6, spsr 378 str r6, [r7, #4] @ Save CPSR 379 str r0, [r7, #8] @ Save OLD_R0 380 mov r0, sp 381 .endm 382 383 .macro irq_restore_user_regs 384 ldmia sp, {r0 - lr}^ @ Calling r0 - lr 385 mov r0, r0 386 ldr lr, [sp, #S_PC] @ Get PC 387 add sp, sp, #S_FRAME_SIZE 388 /* return & move spsr_svc into cpsr */ 389 subs pc, lr, #4 390 .endm 391 392 .macro get_bad_stack 393 ldr r13, IRQ_STACK_START_IN @ setup our mode stack 394 395 str lr, [r13] @ save caller lr / spsr 396 mrs lr, spsr 397 str lr, [r13, #4] 398 399 mov r13, #MODE_SVC @ prepare SVC-Mode 400 @ msr spsr_c, r13 401 msr spsr, r13 402 mov lr, pc 403 movs pc, lr 404 .endm 405 406 .macro get_irq_stack @ setup IRQ stack 407 ldr sp, IRQ_STACK_START 408 .endm 409 410 .macro get_fiq_stack @ setup FIQ stack 411 ldr sp, FIQ_STACK_START 412 .endm 413 414/* 415 * exception handlers 416 */ 417 .align 5 418undefined_instruction: 419 get_bad_stack 420 bad_save_user_regs 421 bl do_undefined_instruction 422 423 .align 5 424software_interrupt: 425 get_bad_stack 426 bad_save_user_regs 427 bl do_software_interrupt 428 429 .align 5 430prefetch_abort: 431 get_bad_stack 432 bad_save_user_regs 433 bl do_prefetch_abort 434 435 .align 5 436data_abort: 437 get_bad_stack 438 bad_save_user_regs 439 bl do_data_abort 440 441 .align 5 442not_used: 443 get_bad_stack 444 bad_save_user_regs 445 bl do_not_used 446 447#ifdef CONFIG_USE_IRQ 448 449 .align 5 450irq: 451 get_irq_stack 452 irq_save_user_regs 453 bl do_irq 454 irq_restore_user_regs 455 456 .align 5 457fiq: 458 get_fiq_stack 459 /* someone ought to write a more effiction fiq_save_user_regs */ 460 irq_save_user_regs 461 bl do_fiq 462 irq_restore_user_regs 463 464#else 465 466 .align 5 467irq: 468 get_bad_stack 469 bad_save_user_regs 470 bl do_irq 471 472 .align 5 473fiq: 474 get_bad_stack 475 bad_save_user_regs 476 bl do_fiq 477 478#endif 479