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
  31 #include <config.h>
  32 #include <version.h>
  33
  34
  35 /*
  36  * Jump vector table
  37  */
  38
  39
  40 .globl _start
  41 _start: b       reset
  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         add     pc, pc, #0x0c000000
  49
  50         .balignl 16,0xdeadbeef
  51
  52
  53 /*
  54  *************************************************************************
  55  *
  56  * Startup Code (reset vector)
  57  *
  58  * do important init only if we don't start from memory!
  59  * relocate u-boot to ram
  60  * setup stack
  61  * jump to second stage
  62  *
  63  *************************************************************************
  64  */
  65
  66 _TEXT_BASE:
  67         .word   TEXT_BASE
  68
  69 .globl _armboot_start
  70 _armboot_start:
  71         .word _start
  72
  73 /*
  74  * These are defined in the board-specific linker script.
  75  */
  76 .globl _bss_start
  77 _bss_start:
  78         .word __bss_start
  79
  80 .globl _bss_end
  81 _bss_end:
  82         .word _end
  83
  84 #ifdef CONFIG_USE_IRQ
  85 /* IRQ stack memory (calculated at run-time) */
  86 .globl IRQ_STACK_START
  87 IRQ_STACK_START:
  88         .word   0x0badc0de
  89
  90 /* IRQ stack memory (calculated at run-time) */
  91 .globl FIQ_STACK_START
  92 FIQ_STACK_START:
  93         .word 0x0badc0de
  94 #endif
  95
  96
  97 /*
  98  * the actual reset code
  99  */
 100
 101 reset:
 102         /*
 103          * set the cpu to SVC32 mode
 104          */
 105         mrs     r0,cpsr
 106         bic     r0,r0,#0x1f
 107         orr     r0,r0,#0x13
 108         msr     cpsr,r0
 109
 110         /*
 111          * we do sys-critical inits only at reboot,
 112          * not when booting from ram!
 113          */
 114
 115 #ifndef CONFIG_SKIP_LOWLEVEL_INIT
 116         bl      cpu_init_crit
 117         /*
 118          * before relocating, we have to setup RAM timing
 119          * because memory timing is board-dependend, you will
 120          * find a lowlevel_init.S in your board directory.
 121          */
 122         bl      lowlevel_init
 123 #endif
 124
 125 #ifndef CONFIG_SKIP_RELOCATE_UBOOT
 126 relocate:                               /* relocate U-Boot to RAM           */
 127         adr     r0, _start              /* r0 <- current position of code   */
 128         ldr     r1, _TEXT_BASE          /* test if we run from flash or RAM */
 129         cmp     r0, r1                  /* don't reloc during debug         */
 130         beq     stack_setup
 131
 132         ldr     r2, _armboot_start
 133         ldr     r3, _bss_start
 134         sub     r2, r3, r2              /* r2 <- size of armboot            */
 135         add     r2, r0, r2              /* r2 <- source end address         */
 136
 137 copy_loop:
 138         ldmia   r0!, {r3-r10}           /* copy from source address [r0]    */
 139         stmia   r1!, {r3-r10}           /* copy to   target address [r1]    */
 140         cmp     r0, r2                  /* until source end addreee [r2]    */
 141         ble     copy_loop
 142
 143 /*
 144         now copy to sram the interrupt vector
 145 */
 146         adr     r0, real_vectors
 147         add     r2, r0, #1024
 148         ldr     r1, =0x0c000000
 149         add     r1, r1, #0x08
 150 vector_copy_loop:
 151         ldmia   r0!, {r3-r10}
 152         stmia   r1!, {r3-r10}
 153         cmp     r0, r2
 154         ble     vector_copy_loop
 155 #endif  /* CONFIG_SKIP_RELOCATE_UBOOT */
 156
 157         /* Set up the stack                                                 */
 158 stack_setup:
 159         ldr     r0, _TEXT_BASE          /* upper 128 KiB: relocated uboot   */
 160         sub     r0, r0, #CONFIG_SYS_MALLOC_LEN  /* malloc area                      */
 161         sub     r0, r0, #CONFIG_SYS_GBL_DATA_SIZE /* bdinfo                        */
 162 #ifdef CONFIG_USE_IRQ
 163         sub     r0, r0, #(CONFIG_STACKSIZE_IRQ+CONFIG_STACKSIZE_FIQ)
 164 #endif
 165         sub     sp, r0, #12             /* leave 3 words for abort-stack    */
 166
 167         ldr     pc, _start_armboot
 168
 169 _start_armboot: .word start_armboot
 170
 171
 172 /*
 173  *************************************************************************
 174  *
 175  * CPU_init_critical registers
 176  *
 177  * setup important registers
 178  * setup memory timing
 179  *
 180  *************************************************************************
 181  */
 182
 183 #define INTCON (0x01c00000+0x200000)
 184 #define INTMSK (0x01c00000+0x20000c)
 185 #define LOCKTIME (0x01c00000+0x18000c)
 186 #define PLLCON (0x01c00000+0x180000)
 187 #define CLKCON (0x01c00000+0x180004)
 188 #define WTCON (0x01c00000+0x130000)
 189 cpu_init_crit:
 190         /* disable watch dog */
 191         ldr     r0, =WTCON
 192         ldr     r1, =0x0
 193         str     r1, [r0]
 194
 195         /*
 196          * mask all IRQs by clearing all bits in the INTMRs
 197          */
 198         ldr     r1,=INTMSK
 199         ldr     r0, =0x03fffeff
 200         str     r0, [r1]
 201
 202         ldr     r1, =INTCON
 203         ldr     r0, =0x05
 204         str     r0, [r1]
 205
 206         /* Set Clock Control Register */
 207         ldr     r1, =LOCKTIME
 208         ldrb    r0, =800
 209         strb    r0, [r1]
 210
 211         ldr     r1, =PLLCON
 212
 213 #if CONFIG_S3C44B0_CLOCK_SPEED==66
 214         ldr     r0, =0x34031    /* 66MHz (Quartz=11MHz) */
 215 #elif CONFIG_S3C44B0_CLOCK_SPEED==75
 216         ldr     r0, =0x610c1 /*B2: Xtal=20mhz Fclk=75MHz  */
 217 #else
 218 # error CONFIG_S3C44B0_CLOCK_SPEED undefined
 219 #endif
 220
 221         str     r0, [r1]
 222
 223         ldr     r1,=CLKCON
 224         ldr     r0, =0x7ff8
 225         str     r0, [r1]
 226
 227         mov     pc, lr
 228
 229
 230 /*************************************************/
 231 /*      interrupt vectors       */
 232 /*************************************************/
 233 real_vectors:
 234         b       reset
 235         b       undefined_instruction
 236         b       software_interrupt
 237         b       prefetch_abort
 238         b       data_abort
 239         b       not_used
 240         b       irq
 241         b       fiq
 242
 243 /*************************************************/
 244
 245 undefined_instruction:
 246         mov     r6, #3
 247         b       reset
 248
 249 software_interrupt:
 250         mov     r6, #4
 251         b       reset
 252
 253 prefetch_abort:
 254         mov     r6, #5
 255         b       reset
 256
 257 data_abort:
 258         mov     r6, #6
 259         b       reset
 260
 261 not_used:
 262         /* we *should* never reach this */
 263         mov     r6, #7
 264         b       reset
 265
 266 irq:
 267         mov     r6, #8
 268         b       reset
 269
 270 fiq:
 271         mov     r6, #9
 272         b       reset