arch/arm/cpu/arm926ejs/start.S

   1 /*
   2  *  armboot - Startup Code for ARM926EJS CPU-core
   3  *
   4  *  Copyright (c) 2003  Texas Instruments
   5  *
   6  *  ----- Adapted for OMAP1610 OMAP730 from ARM925t code ------
   7  *
   8  *  Copyright (c) 2001  Marius Gröger <mag@sysgo.de>
   9  *  Copyright (c) 2002  Alex Züpke <azu@sysgo.de>
  10  *  Copyright (c) 2002  Gary Jennejohn <garyj@denx.de>
  11  *  Copyright (c) 2003  Richard Woodruff <r-woodruff2@ti.com>
  12  *  Copyright (c) 2003  Kshitij <kshitij@ti.com>
  13  *  Copyright (c) 2010  Albert Aribaud <albert.aribaud@free.fr>
  14  *
  15  * See file CREDITS for list of people who contributed to this
  16  * project.
  17  *
  18  * This program is free software; you can redistribute it and/or
  19  * modify it under the terms of the GNU General Public License as
  20  * published by the Free Software Foundation; either version 2 of
  21  * the License, or (at your option) any later version.
  22  *
  23  * This program is distributed in the hope that it will be useful,
  24  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  25  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  26  * GNU General Public License for more details.
  27  *
  28  * You should have received a copy of the GNU General Public License
  29  * along with this program; if not, write to the Free Software
  30  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  31  * MA 02111-1307 USA
  32  */
  33
  34 #include <asm-offsets.h>
  35 #include <config.h>
  36 #include <common.h>
  37 #include <version.h>
  38
  39 #if defined(CONFIG_OMAP1610)
  40 #include <./configs/omap1510.h>
  41 #elif defined(CONFIG_OMAP730)
  42 #include <./configs/omap730.h>
  43 #endif
  44
  45 /*
  46  *************************************************************************
  47  *
  48  * Jump vector table as in table 3.1 in [1]
  49  *
  50  *************************************************************************
  51  */
  52
  53
  54 .globl _start
  55 _start:
  56         b       reset
  57 #ifdef CONFIG_PRELOADER
  58 /* No exception handlers in preloader */
  59         ldr     pc, _hang
  60         ldr     pc, _hang
  61         ldr     pc, _hang
  62         ldr     pc, _hang
  63         ldr     pc, _hang
  64         ldr     pc, _hang
  65         ldr     pc, _hang
  66
  67 _hang:
  68         .word   do_hang
  69 /* pad to 64 byte boundary */
  70         .word   0x12345678
  71         .word   0x12345678
  72         .word   0x12345678
  73         .word   0x12345678
  74         .word   0x12345678
  75         .word   0x12345678
  76         .word   0x12345678
  77 #else
  78         ldr     pc, _undefined_instruction
  79         ldr     pc, _software_interrupt
  80         ldr     pc, _prefetch_abort
  81         ldr     pc, _data_abort
  82         ldr     pc, _not_used
  83         ldr     pc, _irq
  84         ldr     pc, _fiq
  85
  86 _undefined_instruction:
  87         .word undefined_instruction
  88 _software_interrupt:
  89         .word software_interrupt
  90 _prefetch_abort:
  91         .word prefetch_abort
  92 _data_abort:
  93         .word data_abort
  94 _not_used:
  95         .word not_used
  96 _irq:
  97         .word irq
  98 _fiq:
  99         .word fiq
 100
 101 #endif  /* CONFIG_PRELOADER */
 102         .balignl 16,0xdeadbeef
 103
 104
 105 /*
 106  *************************************************************************
 107  *
 108  * Startup Code (reset vector)
 109  *
 110  * do important init only if we don't start from memory!
 111  * setup Memory and board specific bits prior to relocation.
 112  * relocate armboot to ram
 113  * setup stack
 114  *
 115  *************************************************************************
 116  */
 117
 118 .globl _TEXT_BASE
 119 _TEXT_BASE:
 120         .word   CONFIG_SYS_TEXT_BASE
 121
 122 /*
 123  * These are defined in the board-specific linker script.
 124  * Subtracting _start from them lets the linker put their
 125  * relative position in the executable instead of leaving
 126  * them null.
 127  */
 128 .globl _bss_start_ofs
 129 _bss_start_ofs:
 130         .word __bss_start - _start
 131
 132 .globl _bss_end_ofs
 133 _bss_end_ofs:
 134         .word _end - _start
 135
 136 #ifdef CONFIG_USE_IRQ
 137 /* IRQ stack memory (calculated at run-time) */
 138 .globl IRQ_STACK_START
 139 IRQ_STACK_START:
 140         .word   0x0badc0de
 141
 142 /* IRQ stack memory (calculated at run-time) */
 143 .globl FIQ_STACK_START
 144 FIQ_STACK_START:
 145         .word 0x0badc0de
 146 #endif
 147
 148 #if !defined(CONFIG_SYS_ARM_WITHOUT_RELOC)
 149 /* IRQ stack memory (calculated at run-time) + 8 bytes */
 150 .globl IRQ_STACK_START_IN
 151 IRQ_STACK_START_IN:
 152         .word   0x0badc0de
 153
 154 /*
 155  * the actual reset code
 156  */
 157
 158 reset:
 159         /*
 160          * set the cpu to SVC32 mode
 161          */
 162         mrs     r0,cpsr
 163         bic     r0,r0,#0x1f
 164         orr     r0,r0,#0xd3
 165         msr     cpsr,r0
 166
 167         /*
 168          * we do sys-critical inits only at reboot,
 169          * not when booting from ram!
 170          */
 171 #ifndef CONFIG_SKIP_LOWLEVEL_INIT
 172         bl      cpu_init_crit
 173 #endif
 174
 175 /* Set stackpointer in internal RAM to call board_init_f */
 176 call_board_init_f:
 177         ldr     sp, =(CONFIG_SYS_INIT_SP_ADDR)
 178         ldr     r0,=0x00000000
 179         bl      board_init_f
 180
 181 /*------------------------------------------------------------------------------*/
 182
 183 /*
 184  * void relocate_code (addr_sp, gd, addr_moni)
 185  *
 186  * This "function" does not return, instead it continues in RAM
 187  * after relocating the monitor code.
 188  *
 189  */
 190         .globl  relocate_code
 191 relocate_code:
 192         mov     r4, r0  /* save addr_sp */
 193         mov     r5, r1  /* save addr of gd */
 194         mov     r6, r2  /* save addr of destination */
 195         mov     r7, r2  /* save addr of destination */
 196
 197         /* Set up the stack                                                 */
 198 stack_setup:
 199         mov     sp, r4
 200
 201         adr     r0, _start
 202         ldr     r2, _TEXT_BASE
 203         ldr     r3, _bss_start_ofs
 204         add     r2, r0, r3              /* r2 <- source end address         */
 205         cmp     r0, r6
 206         beq     clear_bss
 207
 208 #ifndef CONFIG_SKIP_RELOCATE_UBOOT
 209 copy_loop:
 210         ldmia   r0!, {r9-r10}           /* copy from source address [r0]    */
 211         stmia   r6!, {r9-r10}           /* copy to   target address [r1]    */
 212         cmp     r0, r2                  /* until source end address [r2]    */
 213         blo     copy_loop
 214
 215 #ifndef CONFIG_PRELOADER
 216         /*
 217          * fix .rel.dyn relocations
 218          */
 219         ldr     r0, _TEXT_BASE          /* r0 <- Text base */
 220         sub     r9, r7, r0              /* r9 <- relocation offset */
 221         ldr     r10, _dynsym_start_ofs  /* r10 <- sym table ofs */
 222         add     r10, r10, r0            /* r10 <- sym table in FLASH */
 223         ldr     r2, _rel_dyn_start_ofs  /* r2 <- rel dyn start ofs */
 224         add     r2, r2, r0              /* r2 <- rel dyn start in FLASH */
 225         ldr     r3, _rel_dyn_end_ofs    /* r3 <- rel dyn end ofs */
 226         add     r3, r3, r0              /* r3 <- rel dyn end in FLASH */
 227 fixloop:
 228         ldr     r0, [r2]                /* r0 <- location to fix up, IN FLASH! */
 229         add     r0, r0, r9              /* r0 <- location to fix up in RAM */
 230         ldr     r1, [r2, #4]
 231         and     r8, r1, #0xff
 232         cmp     r8, #23                 /* relative fixup? */
 233         beq     fixrel
 234         cmp     r8, #2                  /* absolute fixup? */
 235         beq     fixabs
 236         /* ignore unknown type of fixup */
 237         b       fixnext
 238 fixabs:
 239         /* absolute fix: set location to (offset) symbol value */
 240         mov     r1, r1, LSR #4          /* r1 <- symbol index in .dynsym */
 241         add     r1, r10, r1             /* r1 <- address of symbol in table */
 242         ldr     r1, [r1, #4]            /* r1 <- symbol value */
 243         add     r1, r9                  /* r1 <- relocated sym addr */
 244         b       fixnext
 245 fixrel:
 246         /* relative fix: increase location by offset */
 247         ldr     r1, [r0]
 248         add     r1, r1, r9
 249 fixnext:
 250         str     r1, [r0]
 251         add     r2, r2, #8              /* each rel.dyn entry is 8 bytes */
 252         cmp     r2, r3
 253         blo     fixloop
 254 #endif
 255 #endif  /* #ifndef CONFIG_SKIP_RELOCATE_UBOOT */
 256
 257 clear_bss:
 258 #ifndef CONFIG_PRELOADER
 259         ldr     r0, _bss_start_ofs
 260         ldr     r1, _bss_end_ofs
 261         ldr     r3, _TEXT_BASE          /* Text base */
 262         mov     r4, r7                  /* reloc addr */
 263         add     r0, r0, r4
 264         add     r1, r1, r4
 265         mov     r2, #0x00000000         /* clear                            */
 266
 267 clbss_l:str     r2, [r0]                /* clear loop...                    */
 268         add     r0, r0, #4
 269         cmp     r0, r1
 270         bne     clbss_l
 271
 272         bl coloured_LED_init
 273         bl red_LED_on
 274 #endif
 275
 276 /*
 277  * We are done. Do not return, instead branch to second part of board
 278  * initialization, now running from RAM.
 279  */
 280 #ifdef CONFIG_NAND_SPL
 281         ldr     r0, _nand_boot_ofs
 282         mov     pc, r0
 283
 284 _nand_boot_ofs:
 285         .word nand_boot
 286 #else
 287         ldr     r0, _board_init_r_ofs
 288         adr     r1, _start
 289         add     lr, r0, r1
 290 #ifndef CONFIG_SKIP_RELOCATE_UBOOT
 291         add     lr, lr, r9
 292 #endif
 293         /* setup parameters for board_init_r */
 294         mov     r0, r5          /* gd_t */
 295         mov     r1, r7          /* dest_addr */
 296         /* jump to it ... */
 297         mov     pc, lr
 298
 299 _board_init_r_ofs:
 300         .word board_init_r - _start
 301 #endif
 302
 303 _rel_dyn_start_ofs:
 304         .word __rel_dyn_start - _start
 305 _rel_dyn_end_ofs:
 306         .word __rel_dyn_end - _start
 307 _dynsym_start_ofs:
 308         .word __dynsym_start - _start
 309
 310 #else /* #if !defined(CONFIG_SYS_ARM_WITHOUT_RELOC) */
 311 /*
 312  * the actual reset code
 313  */
 314
 315 reset:
 316         /*
 317          * set the cpu to SVC32 mode
 318          */
 319         mrs     r0,cpsr
 320         bic     r0,r0,#0x1f
 321         orr     r0,r0,#0xd3
 322         msr     cpsr,r0
 323
 324         /*
 325          * we do sys-critical inits only at reboot,
 326          * not when booting from ram!
 327          */
 328 #ifndef CONFIG_SKIP_LOWLEVEL_INIT
 329         bl      cpu_init_crit
 330 #endif
 331
 332 #ifndef CONFIG_SKIP_RELOCATE_UBOOT
 333 relocate:                               /* relocate U-Boot to RAM           */
 334         adr     r0, _start              /* r0 <- current position of code   */
 335         ldr     r1, _TEXT_BASE          /* test if we run from flash or RAM */
 336         cmp     r0, r1                  /* don't reloc during debug         */
 337         beq     stack_setup
 338         ldr     r3, _bss_start_ofs      /* r3 <- _bss_start - _start        */
 339         add     r2, r0, r3              /* r2 <- source end address         */
 340
 341 copy_loop:
 342         ldmia   r0!, {r3-r10}           /* copy from source address [r0]    */
 343         stmia   r1!, {r3-r10}           /* copy to   target address [r1]    */
 344         cmp     r0, r2                  /* until source end address [r2]    */
 345         blo     copy_loop
 346 #endif  /* CONFIG_SKIP_RELOCATE_UBOOT */
 347
 348         /* Set up the stack                                                 */
 349 stack_setup:
 350         ldr     r0, _TEXT_BASE          /* upper 128 KiB: relocated uboot   */
 351         sub     sp, r0, #128            /* leave 32 words for abort-stack   */
 352 #ifndef CONFIG_PRELOADER
 353         sub     r0, r0, #CONFIG_SYS_MALLOC_LEN  /* malloc area                      */
 354         sub     r0, r0, #GENERATED_GBL_DATA_SIZE /* bdinfo                        */
 355 #ifdef CONFIG_USE_IRQ
 356         sub     r0, r0, #(CONFIG_STACKSIZE_IRQ+CONFIG_STACKSIZE_FIQ)
 357 #endif
 358 #endif /* CONFIG_PRELOADER */
 359         sub     sp, r0, #12             /* leave 3 words for abort-stack    */
 360         bic     sp, sp, #7              /* 8-byte alignment for ABI compliance */
 361
 362 clear_bss:
 363         adr     r2, _start
 364         ldr     r0, _bss_start_ofs      /* find start of bss segment        */
 365         add     r0, r0, r2
 366         ldr     r1, _bss_end_ofs        /* stop here                        */
 367         add     r1, r1, r2
 368         mov     r2, #0x00000000         /* clear                            */
 369
 370 #ifndef CONFIG_PRELOADER
 371 clbss_l:str     r2, [r0]                /* clear loop...                    */
 372         add     r0, r0, #4
 373         cmp     r0, r1
 374         blo     clbss_l
 375
 376         bl coloured_LED_init
 377         bl red_LED_on
 378 #endif /* CONFIG_PRELOADER */
 379
 380         ldr     r0, _start_armboot_ofs
 381         adr     r1, _start
 382         add     r0, r0, r1
 383         ldr     pc, r0
 384
 385 _start_armboot_ofs:
 386 #ifdef CONFIG_NAND_SPL
 387         .word nand_boot - _start
 388 #else
 389         .word start_armboot - _start
 390 #endif /* CONFIG_NAND_SPL */
 391 #endif /* #if !defined(CONFIG_SYS_ARM_WITHOUT_RELOC) */
 392
 393 /*
 394  *************************************************************************
 395  *
 396  * CPU_init_critical registers
 397  *
 398  * setup important registers
 399  * setup memory timing
 400  *
 401  *************************************************************************
 402  */
 403 #ifndef CONFIG_SKIP_LOWLEVEL_INIT
 404 cpu_init_crit:
 405         /*
 406          * flush v4 I/D caches
 407          */
 408         mov     r0, #0
 409         mcr     p15, 0, r0, c7, c7, 0   /* flush v3/v4 cache */
 410         mcr     p15, 0, r0, c8, c7, 0   /* flush v4 TLB */
 411
 412         /*
 413          * disable MMU stuff and caches
 414          */
 415         mrc     p15, 0, r0, c1, c0, 0
 416         bic     r0, r0, #0x00002300     /* clear bits 13, 9:8 (--V- --RS) */
 417         bic     r0, r0, #0x00000087     /* clear bits 7, 2:0 (B--- -CAM) */
 418         orr     r0, r0, #0x00000002     /* set bit 2 (A) Align */
 419         orr     r0, r0, #0x00001000     /* set bit 12 (I) I-Cache */
 420         mcr     p15, 0, r0, c1, c0, 0
 421
 422         /*
 423          * Go setup Memory and board specific bits prior to relocation.
 424          */
 425         mov     ip, lr          /* perserve link reg across call */
 426         bl      lowlevel_init   /* go setup pll,mux,memory */
 427         mov     lr, ip          /* restore link */
 428         mov     pc, lr          /* back to my caller */
 429 #endif /* CONFIG_SKIP_LOWLEVEL_INIT */
 430
 431 #ifndef CONFIG_PRELOADER
 432 /*
 433  *************************************************************************
 434  *
 435  * Interrupt handling
 436  *
 437  *************************************************************************
 438  */
 439
 440 @
 441 @ IRQ stack frame.
 442 @
 443 #define S_FRAME_SIZE    72
 444
 445 #define S_OLD_R0        68
 446 #define S_PSR           64
 447 #define S_PC            60
 448 #define S_LR            56
 449 #define S_SP            52
 450
 451 #define S_IP            48
 452 #define S_FP            44
 453 #define S_R10           40
 454 #define S_R9            36
 455 #define S_R8            32
 456 #define S_R7            28
 457 #define S_R6            24
 458 #define S_R5            20
 459 #define S_R4            16
 460 #define S_R3            12
 461 #define S_R2            8
 462 #define S_R1            4
 463 #define S_R0            0
 464
 465 #define MODE_SVC 0x13
 466 #define I_BIT    0x80
 467
 468 /*
 469  * use bad_save_user_regs for abort/prefetch/undef/swi ...
 470  * use irq_save_user_regs / irq_restore_user_regs for IRQ/FIQ handling
 471  */
 472
 473         .macro  bad_save_user_regs
 474         @ carve out a frame on current user stack
 475         sub     sp, sp, #S_FRAME_SIZE
 476         stmia   sp, {r0 - r12}  @ Save user registers (now in svc mode) r0-r12
 477 #if defined(CONFIG_SYS_ARM_WITHOUT_RELOC)
 478         adr     r2, _start
 479         sub     r2, r2, #(CONFIG_STACKSIZE+CONFIG_SYS_MALLOC_LEN)
 480         sub     r2, r2, #(GENERATED_GBL_DATA_SIZE+8)  @ set base 2 words into abort stack
 481 #else
 482         ldr     r2, IRQ_STACK_START_IN
 483 #endif
 484         @ get values for "aborted" pc and cpsr (into parm regs)
 485         ldmia   r2, {r2 - r3}
 486         add     r0, sp, #S_FRAME_SIZE           @ grab pointer to old stack
 487         add     r5, sp, #S_SP
 488         mov     r1, lr
 489         stmia   r5, {r0 - r3}   @ save sp_SVC, lr_SVC, pc, cpsr
 490         mov     r0, sp          @ save current stack into r0 (param register)
 491         .endm
 492
 493         .macro  irq_save_user_regs
 494         sub     sp, sp, #S_FRAME_SIZE
 495         stmia   sp, {r0 - r12}                  @ Calling r0-r12
 496         @ !!!! R8 NEEDS to be saved !!!! a reserved stack spot would be good.
 497         add     r8, sp, #S_PC
 498         stmdb   r8, {sp, lr}^           @ Calling SP, LR
 499         str     lr, [r8, #0]            @ Save calling PC
 500         mrs     r6, spsr
 501         str     r6, [r8, #4]            @ Save CPSR
 502         str     r0, [r8, #8]            @ Save OLD_R0
 503         mov     r0, sp
 504         .endm
 505
 506         .macro  irq_restore_user_regs
 507         ldmia   sp, {r0 - lr}^                  @ Calling r0 - lr
 508         mov     r0, r0
 509         ldr     lr, [sp, #S_PC]                 @ Get PC
 510         add     sp, sp, #S_FRAME_SIZE
 511         subs    pc, lr, #4              @ return & move spsr_svc into cpsr
 512         .endm
 513
 514         .macro get_bad_stack
 515 #if defined(CONFIG_SYS_ARM_WITHOUT_RELOC)
 516         adr     r13, _start             @ setup our mode stack
 517         sub     r13, r13, #(CONFIG_STACKSIZE+CONFIG_SYS_MALLOC_LEN)
 518         sub     r13, r13, #(GENERATED_GBL_DATA_SIZE+8) @ reserved a couple spots in abort stack
 519 #else
 520         ldr     r13, IRQ_STACK_START_IN         @ setup our mode stack
 521 #endif
 522
 523         str     lr, [r13]       @ save caller lr in position 0 of saved stack
 524         mrs     lr, spsr        @ get the spsr
 525         str     lr, [r13, #4]   @ save spsr in position 1 of saved stack
 526         mov     r13, #MODE_SVC  @ prepare SVC-Mode
 527         @ msr   spsr_c, r13
 528         msr     spsr, r13       @ switch modes, make sure moves will execute
 529         mov     lr, pc          @ capture return pc
 530         movs    pc, lr          @ jump to next instruction & switch modes.
 531         .endm
 532
 533         .macro get_irq_stack                    @ setup IRQ stack
 534         ldr     sp, IRQ_STACK_START
 535         .endm
 536
 537         .macro get_fiq_stack                    @ setup FIQ stack
 538         ldr     sp, FIQ_STACK_START
 539         .endm
 540 #endif  /* CONFIG_PRELOADER */
 541
 542 /*
 543  * exception handlers
 544  */
 545 #ifdef CONFIG_PRELOADER
 546         .align  5
 547 do_hang:
 548         ldr     sp, _TEXT_BASE                  /* switch to abort stack */
 549 1:
 550         bl      1b                              /* hang and never return */
 551 #else   /* !CONFIG_PRELOADER */
 552         .align  5
 553 undefined_instruction:
 554         get_bad_stack
 555         bad_save_user_regs
 556         bl      do_undefined_instruction
 557
 558         .align  5
 559 software_interrupt:
 560         get_bad_stack
 561         bad_save_user_regs
 562         bl      do_software_interrupt
 563
 564         .align  5
 565 prefetch_abort:
 566         get_bad_stack
 567         bad_save_user_regs
 568         bl      do_prefetch_abort
 569
 570         .align  5
 571 data_abort:
 572         get_bad_stack
 573         bad_save_user_regs
 574         bl      do_data_abort
 575
 576         .align  5
 577 not_used:
 578         get_bad_stack
 579         bad_save_user_regs
 580         bl      do_not_used
 581
 582 #ifdef CONFIG_USE_IRQ
 583
 584         .align  5
 585 irq:
 586         get_irq_stack
 587         irq_save_user_regs
 588         bl      do_irq
 589         irq_restore_user_regs
 590
 591         .align  5
 592 fiq:
 593         get_fiq_stack
 594         /* someone ought to write a more effiction fiq_save_user_regs */
 595         irq_save_user_regs
 596         bl      do_fiq
 597         irq_restore_user_regs
 598
 599 #else
 600
 601         .align  5
 602 irq:
 603         get_bad_stack
 604         bad_save_user_regs
 605         bl      do_irq
 606
 607         .align  5
 608 fiq:
 609         get_bad_stack
 610         bad_save_user_regs
 611         bl      do_fiq
 612
 613 #endif
 614 #endif  /* CONFIG_PRELOADER */