cpu/xscale/start.S

   1 /*
   2  *  armboot - Startup Code for XScale
   3  *
   4  *  Copyright (C) 1998  Dan Malek <dmalek@jlc.net>
   5  *  Copyright (C) 1999  Magnus Damm <kieraypc01.p.y.kie.era.ericsson.se>
   6  *  Copyright (C) 2000  Wolfgang Denk <wd@denx.de>
   7  *  Copyright (c) 2001  Alex Züpke <azu@sysgo.de>
   8  *  Copyright (c) 2002  Kyle Harris <kharris@nexus-tech.net>
   9  *
  10  * See file CREDITS for list of people who contributed to this
  11  * project.
  12  *
  13  * This program is free software; you can redistribute it and/or
  14  * modify it under the terms of the GNU General Public License as
  15  * published by the Free Software Foundation; either version 2 of
  16  * the License, or (at your option) any later version.
  17  *
  18  * This program is distributed in the hope that it will be useful,
  19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21  * GNU General Public License for more details.
  22  *
  23  * You should have received a copy of the GNU General Public License
  24  * along with this program; if not, write to the Free Software
  25  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  26  * MA 02111-1307 USA
  27  */
  28
  29
  30
  31 #include <config.h>
  32 #include <version.h>
  33
  34 .globl _start
  35 _start: b       reset
  36         ldr     pc, _undefined_instruction
  37         ldr     pc, _software_interrupt
  38         ldr     pc, _prefetch_abort
  39         ldr     pc, _data_abort
  40         ldr     pc, _not_used
  41         ldr     pc, _irq
  42         ldr     pc, _fiq
  43
  44 _undefined_instruction: .word undefined_instruction
  45 _software_interrupt:    .word software_interrupt
  46 _prefetch_abort:        .word prefetch_abort
  47 _data_abort:            .word data_abort
  48 _not_used:              .word not_used
  49 _irq:                   .word irq
  50 _fiq:                   .word fiq
  51
  52         .balignl 16,0xdeadbeef
  53
  54
  55 /*
  56  * Startup Code (reset vector)
  57  *
  58  * do important init only if we don't start from memory!
  59  * - relocate armboot to ram
  60  * - setup stack
  61  * - jump to second stage
  62  */
  63
  64 /*
  65  * CFG_MEM_END is in the board dependent config-file (configs/config_BOARD.h)
  66  */
  67 _TEXT_BASE:
  68         .word   TEXT_BASE
  69
  70 .globl _armboot_start
  71 _armboot_start:
  72         .word _start
  73
  74 /*
  75  * Note: _armboot_end_data and _armboot_end are defined
  76  * by the (board-dependent) linker script.
  77  * _armboot_end_data is the first usable FLASH address after armboot
  78  */
  79 .globl _armboot_end_data
  80 _armboot_end_data:
  81         .word armboot_end_data
  82 .globl _armboot_end
  83 _armboot_end:
  84         .word armboot_end
  85
  86 /*
  87  * This is defined in the board specific linker script
  88  */
  89 .globl _bss_start
  90 _bss_start:
  91         .word bss_start
  92
  93 .globl _bss_end
  94 _bss_end:
  95         .word bss_end
  96
  97 /*
  98  * _armboot_real_end is the first usable RAM address behind armboot
  99  * and the various stacks
 100  */
 101 .globl _armboot_real_end
 102 _armboot_real_end:
 103         .word 0x0badc0de
 104
 105 /*
 106  * We relocate uboot to this address (end of RAM - 128 KiB)
 107  */
 108 .globl _uboot_reloc
 109 _uboot_reloc:
 110         .word TEXT_BASE
 111
 112 #ifdef CONFIG_USE_IRQ
 113 /* IRQ stack memory (calculated at run-time) */
 114 .globl IRQ_STACK_START
 115 IRQ_STACK_START:
 116         .word   0x0badc0de
 117
 118 /* IRQ stack memory (calculated at run-time) */
 119 .globl FIQ_STACK_START
 120 FIQ_STACK_START:
 121         .word 0x0badc0de
 122 #endif
 123
 124
 125 /****************************************************************************/
 126 /*                                                                          */
 127 /* the actual reset code                                                    */
 128 /*                                                                          */
 129 /****************************************************************************/
 130
 131 reset:
 132         mrs     r0,cpsr                 /* set the cpu to SVC32 mode        */
 133         bic     r0,r0,#0x1f             /* (superviser mode, M=10011)       */
 134         orr     r0,r0,#0x13
 135         msr     cpsr,r0
 136
 137         bl      cpu_init_crit           /* we do sys-critical inits         */
 138
 139 relocate:                               /* relocate U-Boot to RAM          */
 140         adr     r0, _start              /* r0 <- current position of code */
 141         ldr     r2, _armboot_start
 142         ldr     r3, _armboot_end
 143         sub     r2, r3, r2              /* r2 <- size of armboot */
 144         ldr     r1, _TEXT_BASE
 145         add     r2, r0, r2              /* r2 <- source end address */
 146
 147 copy_loop:
 148         ldmia   r0!, {r3-r10}           /* copy from source address [r0]    */
 149         stmia   r1!, {r3-r10}           /* copy to   target address [r1]    */
 150         cmp     r0, r2                  /* until source end addreee [r2]    */
 151         ble     copy_loop
 152
 153         /* Set up the stack                                                 */
 154         ldr     r0, _uboot_reloc        /* upper 128 KiB: relocated uboot   */
 155         sub     r0, r0, #CFG_MALLOC_LEN /* malloc area                      */
 156                                         /* FIXME: bdinfo should be here     */
 157         sub     sp, r0, #12             /* leave 3 words for abort-stack    */
 158
 159 clear_bss:
 160
 161         ldr     r0, _bss_start          /* find start of bss segment        */
 162         add     r0, r0, #4              /* start at first byte of bss       */
 163         ldr     r1, _bss_end            /* stop here                        */
 164         mov     r2, #0x00000000         /* clear                            */
 165
 166 clbss_l:str     r2, [r0]                /* clear loop...                    */
 167         add     r0, r0, #4
 168         cmp     r0, r1
 169         bne     clbss_l
 170
 171
 172         ldr     pc, _start_armboot
 173
 174 _start_armboot: .word start_armboot
 175
 176
 177 /****************************************************************************/
 178 /*                                                                          */
 179 /* CPU_init_critical registers                                              */
 180 /*                                                                          */
 181 /* - setup important registers                                              */
 182 /* - setup memory timing                                                    */
 183 /*                                                                          */
 184 /****************************************************************************/
 185
 186         /* Interrupt-Controller base address                                */
 187 IC_BASE:           .word           0x40d00000
 188 #define ICMR    0x04
 189
 190 /* Reset-Controller */
 191 RST_BASE:       .word   0x40f00030
 192 #define RCSR    0x00
 193
 194         /* Operating System Timer */
 195 OSTIMER_BASE:   .word   0x40a00000
 196 #define OSMR3   0x0C
 197 #define OSCR    0x10
 198 #define OWER    0x18
 199 #define OIER    0x1C
 200
 201         /* Clock Manager Registers                                          */
 202 #ifdef CFG_CPUSPEED
 203 CC_BASE:        .word   0x41300000
 204 #define CCCR    0x00
 205 cpuspeed:       .word   CFG_CPUSPEED
 206 #endif
 207         /* RS: ???                                                          */
 208         .macro CPWAIT
 209         mrc  p15,0,r0,c2,c0,0
 210         mov  r0,r0
 211         sub  pc,pc,#4
 212         .endm
 213
 214
 215 cpu_init_crit:
 216
 217         /* mask all IRQs                                                    */
 218         ldr     r0, IC_BASE
 219         mov     r1, #0x00
 220         str     r1, [r0, #ICMR]
 221
 222 #ifdef CFG_CPUSPEED
 223         /* set clock speed */
 224         ldr     r0, CC_BASE
 225         ldr     r1, cpuspeed
 226         str     r1, [r0, #CCCR]
 227         mov     r0, #3
 228         mcr     p14, 0, r0, c6, c0, 0
 229 #endif
 230
 231         /*
 232          * before relocating, we have to setup RAM timing
 233          * because memory timing is board-dependend, you will
 234          * find a memsetup.S in your board directory.
 235          */
 236         mov     ip,     lr
 237         bl      memsetup
 238         mov     lr,     ip
 239
 240         /* Memory interfaces are working. Disable MMU and enable I-cache.   */
 241
 242         ldr     r0, =0x2001             /* enable access to all coproc.     */
 243         mcr     p15, 0, r0, c15, c1, 0
 244         CPWAIT
 245
 246         mcr     p15, 0, r0, c7, c10, 4  /* drain the write & fill buffers   */
 247         CPWAIT
 248
 249         mcr     p15, 0, r0, c7, c7, 0   /* flush Icache, Dcache and BTB     */
 250         CPWAIT
 251
 252         mcr     p15, 0, r0, c8, c7, 0   /* flush instuction and data TLBs   */
 253         CPWAIT
 254
 255         /* Enable the Icache                                                */
 256 /*
 257         mrc     p15, 0, r0, c1, c0, 0
 258         orr     r0, r0, #0x1800
 259         mcr     p15, 0, r0, c1, c0, 0
 260         CPWAIT
 261 */
 262         mov     pc, lr
 263
 264
 265 /****************************************************************************/
 266 /*                                                                          */
 267 /* Interrupt handling                                                       */
 268 /*                                                                          */
 269 /****************************************************************************/
 270
 271 /* IRQ stack frame                                                          */
 272
 273 #define S_FRAME_SIZE    72
 274
 275 #define S_OLD_R0        68
 276 #define S_PSR           64
 277 #define S_PC            60
 278 #define S_LR            56
 279 #define S_SP            52
 280
 281 #define S_IP            48
 282 #define S_FP            44
 283 #define S_R10           40
 284 #define S_R9            36
 285 #define S_R8            32
 286 #define S_R7            28
 287 #define S_R6            24
 288 #define S_R5            20
 289 #define S_R4            16
 290 #define S_R3            12
 291 #define S_R2            8
 292 #define S_R1            4
 293 #define S_R0            0
 294
 295 #define MODE_SVC 0x13
 296
 297         /* use bad_save_user_regs for abort/prefetch/undef/swi ...          */
 298
 299         .macro  bad_save_user_regs
 300         sub     sp, sp, #S_FRAME_SIZE
 301         stmia   sp, {r0 - r12}                  /* Calling r0-r12           */
 302         add     r8, sp, #S_PC
 303
 304         ldr     r2, _armboot_end
 305         add     r2, r2, #CONFIG_STACKSIZE
 306         sub     r2, r2, #8
 307         ldmia   r2, {r2 - r4}                   /* get pc, cpsr, old_r0     */
 308         add     r0, sp, #S_FRAME_SIZE           /* restore sp_SVC           */
 309
 310         add     r5, sp, #S_SP
 311         mov     r1, lr
 312         stmia   r5, {r0 - r4}                   /* save sp_SVC, lr_SVC, pc, cpsr, old_r */
 313         mov     r0, sp
 314         .endm
 315
 316
 317         /* use irq_save_user_regs / irq_restore_user_regs for                */
 318         /* IRQ/FIQ handling                                                  */
 319
 320         .macro  irq_save_user_regs
 321         sub     sp, sp, #S_FRAME_SIZE
 322         stmia   sp, {r0 - r12}                  /* Calling r0-r12            */
 323         add     r8, sp, #S_PC
 324         stmdb   r8, {sp, lr}^                   /* Calling SP, LR            */
 325         str     lr, [r8, #0]                    /* Save calling PC           */
 326         mrs     r6, spsr
 327         str     r6, [r8, #4]                    /* Save CPSR                 */
 328         str     r0, [r8, #8]                    /* Save OLD_R0               */
 329         mov     r0, sp
 330         .endm
 331
 332         .macro  irq_restore_user_regs
 333         ldmia   sp, {r0 - lr}^                  @ Calling r0 - lr
 334         mov     r0, r0
 335         ldr     lr, [sp, #S_PC]                 @ Get PC
 336         add     sp, sp, #S_FRAME_SIZE
 337         subs    pc, lr, #4                      @ return & move spsr_svc into cpsr
 338         .endm
 339
 340         .macro get_bad_stack
 341         ldr     r13, _armboot_end               @ setup our mode stack
 342         add     r13, r13, #CONFIG_STACKSIZE     @ resides at top of normal stack
 343         sub     r13, r13, #8
 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 /****************************************************************************/
 365 /*                                                                          */
 366 /* exception handlers                                                       */
 367 /*                                                                          */
 368 /****************************************************************************/
 369
 370         .align  5
 371 undefined_instruction:
 372         get_bad_stack
 373         bad_save_user_regs
 374         bl      do_undefined_instruction
 375
 376         .align  5
 377 software_interrupt:
 378         get_bad_stack
 379         bad_save_user_regs
 380         bl      do_software_interrupt
 381
 382         .align  5
 383 prefetch_abort:
 384         get_bad_stack
 385         bad_save_user_regs
 386         bl      do_prefetch_abort
 387
 388         .align  5
 389 data_abort:
 390         get_bad_stack
 391         bad_save_user_regs
 392         bl      do_data_abort
 393
 394         .align  5
 395 not_used:
 396         get_bad_stack
 397         bad_save_user_regs
 398         bl      do_not_used
 399
 400 #ifdef CONFIG_USE_IRQ
 401
 402         .align  5
 403 irq:
 404         get_irq_stack
 405         irq_save_user_regs
 406         bl      do_irq
 407         irq_restore_user_regs
 408
 409         .align  5
 410 fiq:
 411         get_fiq_stack
 412         irq_save_user_regs              /* someone ought to write a more    */
 413         bl      do_fiq                  /* effiction fiq_save_user_regs     */
 414         irq_restore_user_regs
 415
 416 #else
 417
 418         .align  5
 419 irq:
 420         get_bad_stack
 421         bad_save_user_regs
 422         bl      do_irq
 423
 424         .align  5
 425 fiq:
 426         get_bad_stack
 427         bad_save_user_regs
 428         bl      do_fiq
 429
 430 #endif
 431
 432 /************************************************************************/
 433 /*                                                                      */
 434 /* Reset function: the PXA250 has no reset function, so we have to      */
 435 /* perform a watchdog timeout to cause a reset.                         */
 436 /*                                                                      */
 437 /************************************************************************/
 438         .align  5
 439 .globl reset_cpu
 440 reset_cpu:
 441         /* We set OWE:WME (watchdog enable) and wait until timeout happens  */
 442
 443         ldr     r0, OSTIMER_BASE
 444         ldr     r1, [r0, #OWER]
 445         orr     r1, r1, #0x0001                 /* bit0: WME                */
 446         str     r1, [r0, #OWER]
 447
 448         /* OS timer does only wrap every 1165 seconds, so we have to set    */
 449         /* the match register as well.                                      */
 450
 451         ldr     r1, [r0, #OSCR]                 /* read OS timer            */
 452         add     r1, r1, #0x800                  /* let OSMR3 match after    */
 453         add     r1, r1, #0x800                  /* 4096*(1/3.6864MHz)=1ms   */
 454         str     r1, [r0, #OSMR3]
 455
 456 reset_endless:
 457
 458         b       reset_endless