1/* 2 * armboot - Startup Code for ARM720 CPU-core 3 * 4 * Copyright (c) 2001 Marius Gröger <mag@sysgo.de> 5 * Copyright (c) 2002 Alex Züpke <azu@sysgo.de> 6 * 7 * See file CREDITS for list of people who contributed to this 8 * project. 9 * 10 * This program is free software; you can redistribute it and/or 11 * modify it under the terms of the GNU General Public License as 12 * published by the Free Software Foundation; either version 2 of 13 * the License, or (at your option) any later version. 14 * 15 * This program is distributed in the hope that it will be useful, 16 * but WITHOUT ANY WARRANTY; without even the implied warranty of 17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 18 * GNU General Public License for more details. 19 * 20 * You should have received a copy of the GNU General Public License 21 * along with this program; if not, write to the Free Software 22 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, 23 * MA 02111-1307 USA 24 */ 25 26#include <asm-offsets.h> 27#include <config.h> 28#include <version.h> 29#include <asm/hardware.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 reset 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#ifdef CONFIG_SPL_BUILD 51_undefined_instruction: .word _undefined_instruction 52_software_interrupt: .word _software_interrupt 53_prefetch_abort: .word _prefetch_abort 54_data_abort: .word _data_abort 55_not_used: .word _not_used 56_irq: .word _irq 57_fiq: .word _fiq 58_pad: .word 0x12345678 /* now 16*4=64 */ 59#else 60_undefined_instruction: .word undefined_instruction 61_software_interrupt: .word software_interrupt 62_prefetch_abort: .word prefetch_abort 63_data_abort: .word data_abort 64_not_used: .word not_used 65_irq: .word irq 66_fiq: .word fiq 67_pad: .word 0x12345678 /* now 16*4=64 */ 68#endif /* CONFIG_SPL_BUILD */ 69 70 .balignl 16,0xdeadbeef 71 72 73/* 74 ************************************************************************* 75 * 76 * Startup Code (reset vector) 77 * 78 * do important init only if we don't start from RAM! 79 * relocate armboot to ram 80 * setup stack 81 * jump to second stage 82 * 83 ************************************************************************* 84 */ 85 86.globl _TEXT_BASE 87_TEXT_BASE: 88#ifdef CONFIG_SPL_BUILD 89 .word CONFIG_SPL_TEXT_BASE 90#else 91 .word CONFIG_SYS_TEXT_BASE 92#endif 93 94/* 95 * These are defined in the board-specific linker script. 96 * Subtracting _start from them lets the linker put their 97 * relative position in the executable instead of leaving 98 * them null. 99 */ 100.globl _bss_start_ofs 101_bss_start_ofs: 102 .word __bss_start - _start 103 104.globl _bss_end_ofs 105_bss_end_ofs: 106 .word __bss_end__ - _start 107 108.globl _end_ofs 109_end_ofs: 110 .word _end - _start 111 112#ifdef CONFIG_USE_IRQ 113/* IRQ stack memory (calculated at run-time) */ 114.globl IRQ_STACK_START 115IRQ_STACK_START: 116 .word 0x0badc0de 117 118/* IRQ stack memory (calculated at run-time) */ 119.globl FIQ_STACK_START 120FIQ_STACK_START: 121 .word 0x0badc0de 122#endif 123 124/* IRQ stack memory (calculated at run-time) + 8 bytes */ 125.globl IRQ_STACK_START_IN 126IRQ_STACK_START_IN: 127 .word 0x0badc0de 128 129/* 130 * the actual reset code 131 */ 132 133reset: 134 /* 135 * set the cpu to SVC32 mode 136 */ 137 mrs r0,cpsr 138 bic r0,r0,#0x1f 139 orr r0,r0,#0xd3 140 msr cpsr,r0 141 142 /* 143 * we do sys-critical inits only at reboot, 144 * not when booting from ram! 145 */ 146#ifndef CONFIG_SKIP_LOWLEVEL_INIT 147 bl cpu_init_crit 148#endif 149 150 bl _main 151 152/*------------------------------------------------------------------------------*/ 153 154/* 155 * void relocate_code (addr_sp, gd, addr_moni) 156 * 157 * This "function" does not return, instead it continues in RAM 158 * after relocating the monitor code. 159 * 160 */ 161 .globl relocate_code 162relocate_code: 163 mov r4, r0 /* save addr_sp */ 164 mov r5, r1 /* save addr of gd */ 165 mov r6, r2 /* save addr of destination */ 166 167 adr r0, _start 168 cmp r0, r6 169 moveq r9, #0 /* no relocation. relocation offset(r9) = 0 */ 170 beq relocate_done /* skip relocation */ 171 mov r1, r6 /* r1 <- scratch for copy_loop */ 172 ldr r3, _bss_start_ofs 173 add r2, r0, r3 /* r2 <- source end address */ 174 175copy_loop: 176 ldmia r0!, {r9-r10} /* copy from source address [r0] */ 177 stmia r1!, {r9-r10} /* copy to target address [r1] */ 178 cmp r0, r2 /* until source end address [r2] */ 179 blo copy_loop 180 181#ifndef CONFIG_SPL_BUILD 182 /* 183 * fix .rel.dyn relocations 184 */ 185 ldr r0, _TEXT_BASE /* r0 <- Text base */ 186 sub r9, r6, r0 /* r9 <- relocation offset */ 187 ldr r10, _dynsym_start_ofs /* r10 <- sym table ofs */ 188 add r10, r10, r0 /* r10 <- sym table in FLASH */ 189 ldr r2, _rel_dyn_start_ofs /* r2 <- rel dyn start ofs */ 190 add r2, r2, r0 /* r2 <- rel dyn start in FLASH */ 191 ldr r3, _rel_dyn_end_ofs /* r3 <- rel dyn end ofs */ 192 add r3, r3, r0 /* r3 <- rel dyn end in FLASH */ 193fixloop: 194 ldr r0, [r2] /* r0 <- location to fix up, IN FLASH! */ 195 add r0, r0, r9 /* r0 <- location to fix up in RAM */ 196 ldr r1, [r2, #4] 197 and r7, r1, #0xff 198 cmp r7, #23 /* relative fixup? */ 199 beq fixrel 200 cmp r7, #2 /* absolute fixup? */ 201 beq fixabs 202 /* ignore unknown type of fixup */ 203 b fixnext 204fixabs: 205 /* absolute fix: set location to (offset) symbol value */ 206 mov r1, r1, LSR #4 /* r1 <- symbol index in .dynsym */ 207 add r1, r10, r1 /* r1 <- address of symbol in table */ 208 ldr r1, [r1, #4] /* r1 <- symbol value */ 209 add r1, r1, r9 /* r1 <- relocated sym addr */ 210 b fixnext 211fixrel: 212 /* relative fix: increase location by offset */ 213 ldr r1, [r0] 214 add r1, r1, r9 215fixnext: 216 str r1, [r0] 217 add r2, r2, #8 /* each rel.dyn entry is 8 bytes */ 218 cmp r2, r3 219 blo fixloop 220#endif 221 222relocate_done: 223 224 mov pc, lr 225 226_rel_dyn_start_ofs: 227 .word __rel_dyn_start - _start 228_rel_dyn_end_ofs: 229 .word __rel_dyn_end - _start 230_dynsym_start_ofs: 231 .word __dynsym_start - _start 232 233 .globl c_runtime_cpu_setup 234c_runtime_cpu_setup: 235 236 mov pc, lr 237 238/* 239 ************************************************************************* 240 * 241 * CPU_init_critical registers 242 * 243 * setup important registers 244 * setup memory timing 245 * 246 ************************************************************************* 247 */ 248 249cpu_init_crit: 250 251#if !defined(CONFIG_TEGRA) 252 mov ip, lr 253 /* 254 * before relocating, we have to setup RAM timing 255 * because memory timing is board-dependent, you will 256 * find a lowlevel_init.S in your board directory. 257 */ 258 bl lowlevel_init 259 mov lr, ip 260#endif 261 262 mov pc, lr 263 264 265#ifndef CONFIG_SPL_BUILD 266/* 267 ************************************************************************* 268 * 269 * Interrupt handling 270 * 271 ************************************************************************* 272 */ 273 274@ 275@ IRQ stack frame. 276@ 277#define S_FRAME_SIZE 72 278 279#define S_OLD_R0 68 280#define S_PSR 64 281#define S_PC 60 282#define S_LR 56 283#define S_SP 52 284 285#define S_IP 48 286#define S_FP 44 287#define S_R10 40 288#define S_R9 36 289#define S_R8 32 290#define S_R7 28 291#define S_R6 24 292#define S_R5 20 293#define S_R4 16 294#define S_R3 12 295#define S_R2 8 296#define S_R1 4 297#define S_R0 0 298 299#define MODE_SVC 0x13 300#define I_BIT 0x80 301 302/* 303 * use bad_save_user_regs for abort/prefetch/undef/swi ... 304 * use irq_save_user_regs / irq_restore_user_regs for IRQ/FIQ handling 305 */ 306 307 .macro bad_save_user_regs 308 sub sp, sp, #S_FRAME_SIZE 309 stmia sp, {r0 - r12} @ Calling r0-r12 310 add r8, sp, #S_PC 311 312 ldr r2, IRQ_STACK_START_IN 313 ldmia r2, {r2 - r4} @ get pc, cpsr, old_r0 314 add r0, sp, #S_FRAME_SIZE @ restore sp_SVC 315 316 add r5, sp, #S_SP 317 mov r1, lr 318 stmia r5, {r0 - r4} @ save sp_SVC, lr_SVC, pc, cpsr, old_r 319 mov r0, sp 320 .endm 321 322 .macro irq_save_user_regs 323 sub sp, sp, #S_FRAME_SIZE 324 stmia sp, {r0 - r12} @ Calling r0-r12 325 add r8, sp, #S_PC 326 stmdb r8, {sp, lr}^ @ Calling SP, LR 327 str lr, [r8, #0] @ Save calling PC 328 mrs r6, spsr 329 str r6, [r8, #4] @ Save CPSR 330 str r0, [r8, #8] @ Save OLD_R0 331 mov r0, sp 332 .endm 333 334 .macro irq_restore_user_regs 335 ldmia sp, {r0 - lr}^ @ Calling r0 - lr 336 mov r0, r0 337 ldr lr, [sp, #S_PC] @ Get PC 338 add sp, sp, #S_FRAME_SIZE 339 subs pc, lr, #4 @ return & move spsr_svc into cpsr 340 .endm 341 342 .macro get_bad_stack 343 ldr r13, IRQ_STACK_START_IN @ setup our mode stack 344 345 str lr, [r13] @ save caller lr / spsr 346 mrs lr, spsr 347 str lr, [r13, #4] 348 349 mov r13, #MODE_SVC @ prepare SVC-Mode 350 msr spsr_c, r13 351 mov lr, pc 352 movs pc, lr 353 .endm 354 355 .macro get_irq_stack @ setup IRQ stack 356 ldr sp, IRQ_STACK_START 357 .endm 358 359 .macro get_fiq_stack @ setup FIQ stack 360 ldr sp, FIQ_STACK_START 361 .endm 362 363/* 364 * exception handlers 365 */ 366 .align 5 367undefined_instruction: 368 get_bad_stack 369 bad_save_user_regs 370 bl do_undefined_instruction 371 372 .align 5 373software_interrupt: 374 get_bad_stack 375 bad_save_user_regs 376 bl do_software_interrupt 377 378 .align 5 379prefetch_abort: 380 get_bad_stack 381 bad_save_user_regs 382 bl do_prefetch_abort 383 384 .align 5 385data_abort: 386 get_bad_stack 387 bad_save_user_regs 388 bl do_data_abort 389 390 .align 5 391not_used: 392 get_bad_stack 393 bad_save_user_regs 394 bl do_not_used 395 396#ifdef CONFIG_USE_IRQ 397 398 .align 5 399irq: 400 get_irq_stack 401 irq_save_user_regs 402 bl do_irq 403 irq_restore_user_regs 404 405 .align 5 406fiq: 407 get_fiq_stack 408 /* someone ought to write a more effiction fiq_save_user_regs */ 409 irq_save_user_regs 410 bl do_fiq 411 irq_restore_user_regs 412 413#else 414 415 .align 5 416irq: 417 get_bad_stack 418 bad_save_user_regs 419 bl do_irq 420 421 .align 5 422fiq: 423 get_bad_stack 424 bad_save_user_regs 425 bl do_fiq 426 427#endif 428#endif /* CONFIG_SPL_BUILD */ 429