arch/arm/cpu/s3c44b0/start.S

   1 /*
   2  * Startup Code for S3C44B0 CPU-core
   3  *
   4  * (C) Copyright 2004
   5  * DAVE Srl
   6  *
   7  * http://www.dave-tech.it
   8  * http://www.wawnet.biz
   9  * mailto:info@wawnet.biz
  10  *
  11  * See file CREDITS for list of people who contributed to this
  12  * project.
  13  *
  14  * This program is free software; you can redistribute it and/or
  15  * modify it under the terms of the GNU General Public License as
  16  * published by the Free Software Foundation; either version 2 of
  17  * the License, or (at your option) any later version.
  18  *
  19  * This program is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with this program; if not, write to the Free Software
  26  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  27  * MA 02111-1307 USA
  28  */
  29
  30 #include <asm-offsets.h>
  31 #include <config.h>
  32 #include <version.h>
  33
  34 /*
  35  * Jump vector table
  36  */
  37
  38
  39 .globl _start
  40 _start: b       reset
  41         add     pc, pc, #0x0c000000
  42         add     pc, pc, #0x0c000000
  43         add     pc, pc, #0x0c000000
  44         add     pc, pc, #0x0c000000
  45         add     pc, pc, #0x0c000000
  46         add     pc, pc, #0x0c000000
  47         add     pc, pc, #0x0c000000
  48
  49         .balignl 16,0xdeadbeef
  50
  51
  52 /*
  53  *************************************************************************
  54  *
  55  * Startup Code (reset vector)
  56  *
  57  * do important init only if we don't start from memory!
  58  * relocate u-boot to ram
  59  * setup stack
  60  * jump to second stage
  61  *
  62  *************************************************************************
  63  */
  64
  65 .globl _TEXT_BASE
  66 _TEXT_BASE:
  67         .word   CONFIG_SYS_TEXT_BASE
  68
  69 /*
  70  * These are defined in the board-specific linker script.
  71  * Subtracting _start from them lets the linker put their
  72  * relative position in the executable instead of leaving
  73  * them null.
  74  */
  75 .globl _bss_start_ofs
  76 _bss_start_ofs:
  77         .word __bss_start - _start
  78
  79 .globl _bss_end_ofs
  80 _bss_end_ofs:
  81         .word __bss_end__ - _start
  82
  83 #ifdef CONFIG_USE_IRQ
  84 /* IRQ stack memory (calculated at run-time) */
  85 .globl IRQ_STACK_START
  86 IRQ_STACK_START:
  87         .word   0x0badc0de
  88
  89 /* IRQ stack memory (calculated at run-time) */
  90 .globl FIQ_STACK_START
  91 FIQ_STACK_START:
  92         .word 0x0badc0de
  93 #endif
  94
  95 /* IRQ stack memory (calculated at run-time) + 8 bytes */
  96 .globl IRQ_STACK_START_IN
  97 IRQ_STACK_START_IN:
  98         .word   0x0badc0de
  99
 100 /*
 101  * the actual reset code
 102  */
 103
 104 reset:
 105         /*
 106          * set the cpu to SVC32 mode
 107          */
 108         mrs     r0,cpsr
 109         bic     r0,r0,#0x1f
 110         orr     r0,r0,#0xd3
 111         msr     cpsr,r0
 112
 113         /*
 114          * we do sys-critical inits only at reboot,
 115          * not when booting from ram!
 116          */
 117 #ifndef CONFIG_SKIP_LOWLEVEL_INIT
 118         bl      cpu_init_crit
 119         /*
 120          * before relocating, we have to setup RAM timing
 121          * because memory timing is board-dependend, you will
 122          * find a lowlevel_init.S in your board directory.
 123          */
 124         bl      lowlevel_init
 125 #endif
 126
 127 /* Set stackpointer in internal RAM to call board_init_f */
 128 call_board_init_f:
 129         ldr     sp, =(CONFIG_SYS_INIT_SP_ADDR)
 130         bic     sp, sp, #7 /* 8-byte alignment for ABI compliance */
 131         ldr     r0,=0x00000000
 132         bl      board_init_f
 133
 134 /*------------------------------------------------------------------------------*/
 135
 136 /*
 137  * void relocate_code (addr_sp, gd, addr_moni)
 138  *
 139  * This "function" does not return, instead it continues in RAM
 140  * after relocating the monitor code.
 141  *
 142  */
 143         .globl  relocate_code
 144 relocate_code:
 145         mov     r4, r0  /* save addr_sp */
 146         mov     r5, r1  /* save addr of gd */
 147         mov     r6, r2  /* save addr of destination */
 148
 149         /* Set up the stack                                                 */
 150 stack_setup:
 151         mov     sp, r4
 152
 153         adr     r0, _start
 154         cmp     r0, r6
 155         beq     clear_bss               /* skip relocation */
 156         mov     r1, r6                  /* r1 <- scratch for copy_loop */
 157         ldr     r3, _bss_start_ofs
 158         add     r2, r0, r3              /* r2 <- source end address         */
 159
 160 copy_loop:
 161         ldmia   r0!, {r9-r10}           /* copy from source address [r0]    */
 162         stmia   r1!, {r9-r10}           /* copy to   target address [r1]    */
 163         cmp     r0, r2                  /* until source end address [r2]    */
 164         blo     copy_loop
 165
 166 #ifndef CONFIG_PRELOADER
 167         /*
 168          * fix .rel.dyn relocations
 169          */
 170         ldr     r0, _TEXT_BASE          /* r0 <- Text base */
 171         sub     r9, r6, r0              /* r9 <- relocation offset */
 172         ldr     r10, _dynsym_start_ofs  /* r10 <- sym table ofs */
 173         add     r10, r10, r0            /* r10 <- sym table in FLASH */
 174         ldr     r2, _rel_dyn_start_ofs  /* r2 <- rel dyn start ofs */
 175         add     r2, r2, r0              /* r2 <- rel dyn start in FLASH */
 176         ldr     r3, _rel_dyn_end_ofs    /* r3 <- rel dyn end ofs */
 177         add     r3, r3, r0              /* r3 <- rel dyn end in FLASH */
 178 fixloop:
 179         ldr     r0, [r2]                /* r0 <- location to fix up, IN FLASH! */
 180         add     r0, r0, r9              /* r0 <- location to fix up in RAM */
 181         ldr     r1, [r2, #4]
 182         and     r7, r1, #0xff
 183         cmp     r7, #23                 /* relative fixup? */
 184         beq     fixrel
 185         cmp     r7, #2                  /* absolute fixup? */
 186         beq     fixabs
 187         /* ignore unknown type of fixup */
 188         b       fixnext
 189 fixabs:
 190         /* absolute fix: set location to (offset) symbol value */
 191         mov     r1, r1, LSR #4          /* r1 <- symbol index in .dynsym */
 192         add     r1, r10, r1             /* r1 <- address of symbol in table */
 193         ldr     r1, [r1, #4]            /* r1 <- symbol value */
 194         add     r1, r1, r9              /* r1 <- relocated sym addr */
 195         b       fixnext
 196 fixrel:
 197         /* relative fix: increase location by offset */
 198         ldr     r1, [r0]
 199         add     r1, r1, r9
 200 fixnext:
 201         str     r1, [r0]
 202         add     r2, r2, #8              /* each rel.dyn entry is 8 bytes */
 203         cmp     r2, r3
 204         blo     fixloop
 205 #endif
 206
 207 clear_bss:
 208 #ifndef CONFIG_PRELOADER
 209         ldr     r0, _bss_start_ofs
 210         ldr     r1, _bss_end_ofs
 211         mov     r4, r6                  /* reloc addr */
 212         add     r0, r0, r4
 213         add     r1, r1, r4
 214         mov     r2, #0x00000000         /* clear                            */
 215
 216 clbss_l:str     r2, [r0]                /* clear loop...                    */
 217         add     r0, r0, #4
 218         cmp     r0, r1
 219         bne     clbss_l
 220
 221         bl coloured_LED_init
 222         bl red_LED_on
 223 #endif
 224
 225 /*
 226  * We are done. Do not return, instead branch to second part of board
 227  * initialization, now running from RAM.
 228  */
 229         ldr     r0, _board_init_r_ofs
 230         adr     r1, _start
 231         add     lr, r0, r1
 232         add     lr, lr, r9
 233         /* setup parameters for board_init_r */
 234         mov     r0, r5          /* gd_t */
 235         mov     r1, r6          /* dest_addr */
 236         /* jump to it ... */
 237         mov     pc, lr
 238
 239 _board_init_r_ofs:
 240         .word board_init_r - _start
 241
 242 _rel_dyn_start_ofs:
 243         .word __rel_dyn_start - _start
 244 _rel_dyn_end_ofs:
 245         .word __rel_dyn_end - _start
 246 _dynsym_start_ofs:
 247         .word __dynsym_start - _start
 248
 249 /*
 250  *************************************************************************
 251  *
 252  * CPU_init_critical registers
 253  *
 254  * setup important registers
 255  * setup memory timing
 256  *
 257  *************************************************************************
 258  */
 259
 260 #define INTCON (0x01c00000+0x200000)
 261 #define INTMSK (0x01c00000+0x20000c)
 262 #define LOCKTIME (0x01c00000+0x18000c)
 263 #define PLLCON (0x01c00000+0x180000)
 264 #define CLKCON (0x01c00000+0x180004)
 265 #define WTCON (0x01c00000+0x130000)
 266 cpu_init_crit:
 267         /* disable watch dog */
 268         ldr     r0, =WTCON
 269         ldr     r1, =0x0
 270         str     r1, [r0]
 271
 272         /*
 273          * mask all IRQs by clearing all bits in the INTMRs
 274          */
 275         ldr     r1,=INTMSK
 276         ldr     r0, =0x03fffeff
 277         str     r0, [r1]
 278
 279         ldr     r1, =INTCON
 280         ldr     r0, =0x05
 281         str     r0, [r1]
 282
 283         /* Set Clock Control Register */
 284         ldr     r1, =LOCKTIME
 285         ldrb    r0, =800
 286         strb    r0, [r1]
 287
 288         ldr     r1, =PLLCON
 289
 290 #if CONFIG_S3C44B0_CLOCK_SPEED==66
 291         ldr     r0, =0x34031    /* 66MHz (Quartz=11MHz) */
 292 #elif CONFIG_S3C44B0_CLOCK_SPEED==75
 293         ldr     r0, =0x610c1 /*B2: Xtal=20mhz Fclk=75MHz  */
 294 #else
 295 # error CONFIG_S3C44B0_CLOCK_SPEED undefined
 296 #endif
 297
 298         str     r0, [r1]
 299
 300         ldr     r1,=CLKCON
 301         ldr     r0, =0x7ff8
 302         str     r0, [r1]
 303
 304         mov     pc, lr
 305
 306
 307 /*************************************************/
 308 /*      interrupt vectors       */
 309 /*************************************************/
 310 real_vectors:
 311         b       reset
 312         b       undefined_instruction
 313         b       software_interrupt
 314         b       prefetch_abort
 315         b       data_abort
 316         b       not_used
 317         b       irq
 318         b       fiq
 319
 320 /*************************************************/
 321
 322 undefined_instruction:
 323         mov     r6, #3
 324         b       reset
 325
 326 software_interrupt:
 327         mov     r6, #4
 328         b       reset
 329
 330 prefetch_abort:
 331         mov     r6, #5
 332         b       reset
 333
 334 data_abort:
 335         mov     r6, #6
 336         b       reset
 337
 338 not_used:
 339         /* we *should* never reach this */
 340         mov     r6, #7
 341         b       reset
 342
 343 irq:
 344         mov     r6, #8
 345         b       reset
 346
 347 fiq:
 348         mov     r6, #9
 349         b       reset