2 * armboot - Startup Code for SA1100 CPU
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>
9 * See file CREDITS for list of people who contributed to this
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License as
14 * published by the Free Software Foundation; either version 2 of
15 * the License, or (at your option) any later version.
17 * This program is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU General Public License for more details.
22 * You should have received a copy of the GNU General Public License
23 * along with this program; if not, write to the Free Software
24 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
28 #include <asm-offsets.h>
33 *************************************************************************
35 * Jump vector table as in table 3.1 in [1]
37 *************************************************************************
43 ldr pc, _undefined_instruction
44 ldr pc, _software_interrupt
45 ldr pc, _prefetch_abort
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
59 .balignl 16,0xdeadbeef
63 *************************************************************************
65 * Startup Code (reset vector)
67 * do important init only if we don't start from memory!
68 * relocate armboot to ram
70 * jump to second stage
72 *************************************************************************
77 .word CONFIG_SYS_TEXT_BASE
80 * These are defined in the board-specific linker script.
81 * Subtracting _start from them lets the linker put their
82 * relative position in the executable instead of leaving
87 .word __bss_start - _start
94 /* IRQ stack memory (calculated at run-time) */
95 .globl IRQ_STACK_START
99 /* IRQ stack memory (calculated at run-time) */
100 .globl FIQ_STACK_START
105 /* IRQ stack memory (calculated at run-time) + 8 bytes */
106 .globl IRQ_STACK_START_IN
111 * the actual reset code
116 * set the cpu to SVC32 mode
124 * we do sys-critical inits only at reboot,
125 * not when booting from ram!
127 #ifndef CONFIG_SKIP_LOWLEVEL_INIT
131 /* Set stackpointer in internal RAM to call board_init_f */
133 ldr sp, =(CONFIG_SYS_INIT_SP_ADDR)
134 bic sp, sp, #7 /* 8-byte alignment for ABI compliance */
138 /*------------------------------------------------------------------------------*/
141 * void relocate_code (addr_sp, gd, addr_moni)
143 * This "function" does not return, instead it continues in RAM
144 * after relocating the monitor code.
149 mov r4, r0 /* save addr_sp */
150 mov r5, r1 /* save addr of gd */
151 mov r6, r2 /* save addr of destination */
153 /* Set up the stack */
159 beq clear_bss /* skip relocation */
160 mov r1, r6 /* r1 <- scratch for copy_loop */
162 ldr r3, _bss_start_ofs
163 add r2, r0, r3 /* r2 <- source end address */
166 ldmia r0!, {r9-r10} /* copy from source address [r0] */
167 stmia r1!, {r9-r10} /* copy to target address [r1] */
168 cmp r0, r2 /* until source end address [r2] */
171 #ifndef CONFIG_PRELOADER
173 * fix .rel.dyn relocations
175 ldr r0, _TEXT_BASE /* r0 <- Text base */
176 sub r9, r6, r0 /* r9 <- relocation offset */
177 ldr r10, _dynsym_start_ofs /* r10 <- sym table ofs */
178 add r10, r10, r0 /* r10 <- sym table in FLASH */
179 ldr r2, _rel_dyn_start_ofs /* r2 <- rel dyn start ofs */
180 add r2, r2, r0 /* r2 <- rel dyn start in FLASH */
181 ldr r3, _rel_dyn_end_ofs /* r3 <- rel dyn end ofs */
182 add r3, r3, r0 /* r3 <- rel dyn end in FLASH */
184 ldr r0, [r2] /* r0 <- location to fix up, IN FLASH! */
185 add r0, r0, r9 /* r0 <- location to fix up in RAM */
188 cmp r7, #23 /* relative fixup? */
190 cmp r7, #2 /* absolute fixup? */
192 /* ignore unknown type of fixup */
195 /* absolute fix: set location to (offset) symbol value */
196 mov r1, r1, LSR #4 /* r1 <- symbol index in .dynsym */
197 add r1, r10, r1 /* r1 <- address of symbol in table */
198 ldr r1, [r1, #4] /* r1 <- symbol value */
199 add r1, r9 /* r1 <- relocated sym addr */
202 /* relative fix: increase location by offset */
207 add r2, r2, #8 /* each rel.dyn entry is 8 bytes */
213 #ifndef CONFIG_PRELOADER
214 ldr r0, _bss_start_ofs
216 ldr r3, _TEXT_BASE /* Text base */
217 mov r4, r6 /* reloc addr */
220 mov r2, #0x00000000 /* clear */
222 clbss_l:str r2, [r0] /* clear loop... */
229 * We are done. Do not return, instead branch to second part of board
230 * initialization, now running from RAM.
232 ldr r0, _board_init_r_ofs
236 /* setup parameters for board_init_r */
237 mov r0, r5 /* gd_t */
238 mov r1, r6 /* dest_addr */
243 .word board_init_r - _start
246 .word __rel_dyn_start - _start
248 .word __rel_dyn_end - _start
250 .word __dynsym_start - _start
253 *************************************************************************
255 * CPU_init_critical registers
257 * setup important registers
258 * setup memory timing
260 *************************************************************************
264 /* Interupt-Controller base address */
265 IC_BASE: .word 0x90050000
269 /* Reset-Controller */
270 RST_BASE: .word 0x90030000
276 PWR_BASE: .word 0x90020000
279 cpuspeed: .word CONFIG_SYS_CPUSPEED
290 /* set clock speed */
296 * before relocating, we have to setup RAM timing
297 * because memory timing is board-dependend, you will
298 * find a lowlevel_init.S in your board directory.
305 * disable MMU stuff and enable I-cache
308 bic r0, r0, #0x00002000 @ clear bit 13 (X)
309 bic r0, r0, #0x0000000f @ clear bits 3-0 (WCAM)
310 orr r0, r0, #0x00001000 @ set bit 12 (I) Icache
311 orr r0, r0, #0x00000002 @ set bit 2 (A) Align
315 * flush v4 I/D caches
318 mcr p15, 0, r0, c7, c7, 0 /* flush v3/v4 cache */
319 mcr p15, 0, r0, c8, c7, 0 /* flush v4 TLB */
325 *************************************************************************
329 *************************************************************************
335 #define S_FRAME_SIZE 72
357 #define MODE_SVC 0x13
361 * use bad_save_user_regs for abort/prefetch/undef/swi ...
362 * use irq_save_user_regs / irq_restore_user_regs for IRQ/FIQ handling
365 .macro bad_save_user_regs
366 sub sp, sp, #S_FRAME_SIZE
367 stmia sp, {r0 - r12} @ Calling r0-r12
370 ldr r2, IRQ_STACK_START_IN
371 ldmia r2, {r2 - r4} @ get pc, cpsr, old_r0
372 add r0, sp, #S_FRAME_SIZE @ restore sp_SVC
376 stmia r5, {r0 - r4} @ save sp_SVC, lr_SVC, pc, cpsr, old_r
380 .macro irq_save_user_regs
381 sub sp, sp, #S_FRAME_SIZE
382 stmia sp, {r0 - r12} @ Calling r0-r12
384 stmdb r8, {sp, lr}^ @ Calling SP, LR
385 str lr, [r8, #0] @ Save calling PC
387 str r6, [r8, #4] @ Save CPSR
388 str r0, [r8, #8] @ Save OLD_R0
392 .macro irq_restore_user_regs
393 ldmia sp, {r0 - lr}^ @ Calling r0 - lr
395 ldr lr, [sp, #S_PC] @ Get PC
396 add sp, sp, #S_FRAME_SIZE
397 subs pc, lr, #4 @ return & move spsr_svc into cpsr
401 ldr r13, IRQ_STACK_START_IN @ setup our mode stack
403 str lr, [r13] @ save caller lr / spsr
407 mov r13, #MODE_SVC @ prepare SVC-Mode
413 .macro get_irq_stack @ setup IRQ stack
414 ldr sp, IRQ_STACK_START
417 .macro get_fiq_stack @ setup FIQ stack
418 ldr sp, FIQ_STACK_START
425 undefined_instruction:
428 bl do_undefined_instruction
434 bl do_software_interrupt
454 #ifdef CONFIG_USE_IRQ
461 irq_restore_user_regs
466 /* someone ought to write a more effiction fiq_save_user_regs */
469 irq_restore_user_regs
491 mov r1, #0x0 @ set bit 3-0 ...
492 str r1, [r0, #RCSR] @ ... to clear in RCSR
494 str r1, [r0, #RSRR] @ and perform reset
495 b reset_cpu @ silly, but repeat endlessly