2 * armboot - Startup Code for ARM920 CPU-core
4 * Copyright (c) 2001 Marius Gröger <mag@sysgo.de>
5 * Copyright (c) 2002 Alex Züpke <azu@sysgo.de>
6 * Copyright (c) 2002 Gary Jennejohn <gj@denx.de>
8 * See file CREDITS for list of people who contributed to this
11 * This program is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License as
13 * published by the Free Software Foundation; either version 2 of
14 * the License, or (at your option) any later version.
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU General Public License for more details.
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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 *************************************************************************
83 * These are defined in the board-specific linker script.
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
107 * the actual reset code
112 * set the cpu to SVC32 mode
119 /* turn off the watchdog */
120 #if defined(CONFIG_S3C2400)
121 # define pWTCON 0x15300000
122 # define INTMSK 0x14400008 /* Interupt-Controller base addresses */
123 # define CLKDIVN 0x14800014 /* clock divisor register */
124 #elif defined(CONFIG_S3C2410)
125 # define pWTCON 0x53000000
126 # define INTMSK 0x4A000008 /* Interupt-Controller base addresses */
127 # define INTSUBMSK 0x4A00001C
128 # define CLKDIVN 0x4C000014 /* clock divisor register */
131 #if defined(CONFIG_S3C2400) || defined(CONFIG_S3C2410)
137 * mask all IRQs by setting all bits in the INTMR - default
142 # if defined(CONFIG_S3C2410)
148 /* FCLK:HCLK:PCLK = 1:2:4 */
149 /* default FCLK is 120 MHz ! */
153 #endif /* CONFIG_S3C2400 || CONFIG_S3C2410 */
156 * we do sys-critical inits only at reboot,
157 * not when booting from ram!
159 #ifndef CONFIG_SKIP_LOWLEVEL_INIT
163 #ifndef CONFIG_SKIP_RELOCATE_UBOOT
164 relocate: /* relocate U-Boot to RAM */
165 adr r0, _start /* r0 <- current position of code */
166 ldr r1, _TEXT_BASE /* test if we run from flash or RAM */
167 cmp r0, r1 /* don't reloc during debug */
170 ldr r2, _armboot_start
172 sub r2, r3, r2 /* r2 <- size of armboot */
173 add r2, r0, r2 /* r2 <- source end address */
176 ldmia r0!, {r3-r10} /* copy from source address [r0] */
177 stmia r1!, {r3-r10} /* copy to target address [r1] */
178 cmp r0, r2 /* until source end addreee [r2] */
180 #endif /* CONFIG_SKIP_RELOCATE_UBOOT */
182 /* Set up the stack */
184 ldr r0, _TEXT_BASE /* upper 128 KiB: relocated uboot */
185 sub r0, r0, #CFG_MALLOC_LEN /* malloc area */
186 sub r0, r0, #CFG_GBL_DATA_SIZE /* bdinfo */
187 #ifdef CONFIG_USE_IRQ
188 sub r0, r0, #(CONFIG_STACKSIZE_IRQ+CONFIG_STACKSIZE_FIQ)
190 sub sp, r0, #12 /* leave 3 words for abort-stack */
193 ldr r0, _bss_start /* find start of bss segment */
194 ldr r1, _bss_end /* stop here */
195 mov r2, #0x00000000 /* clear */
197 clbss_l:str r2, [r0] /* clear loop... */
203 /* try doing this stuff after the relocation */
209 * mask all IRQs by setting all bits in the INTMR - default
215 /* FCLK:HCLK:PCLK = 1:2:4 */
216 /* default FCLK is 120 MHz ! */
220 /* END stuff after relocation */
223 ldr pc, _start_armboot
225 _start_armboot: .word start_armboot
229 *************************************************************************
231 * CPU_init_critical registers
233 * setup important registers
234 * setup memory timing
236 *************************************************************************
242 * flush v4 I/D caches
245 mcr p15, 0, r0, c7, c7, 0 /* flush v3/v4 cache */
246 mcr p15, 0, r0, c8, c7, 0 /* flush v4 TLB */
249 * disable MMU stuff and caches
251 mrc p15, 0, r0, c1, c0, 0
252 bic r0, r0, #0x00002300 @ clear bits 13, 9:8 (--V- --RS)
253 bic r0, r0, #0x00000087 @ clear bits 7, 2:0 (B--- -CAM)
254 orr r0, r0, #0x00000002 @ set bit 2 (A) Align
255 orr r0, r0, #0x00001000 @ set bit 12 (I) I-Cache
256 mcr p15, 0, r0, c1, c0, 0
260 * before relocating, we have to setup RAM timing
261 * because memory timing is board-dependend, you will
262 * find a lowlevel_init.S in your board directory.
272 *************************************************************************
276 *************************************************************************
282 #define S_FRAME_SIZE 72
304 #define MODE_SVC 0x13
308 * use bad_save_user_regs for abort/prefetch/undef/swi ...
309 * use irq_save_user_regs / irq_restore_user_regs for IRQ/FIQ handling
312 .macro bad_save_user_regs
313 sub sp, sp, #S_FRAME_SIZE
314 stmia sp, {r0 - r12} @ Calling r0-r12
315 ldr r2, _armboot_start
316 sub r2, r2, #(CONFIG_STACKSIZE+CFG_MALLOC_LEN)
317 sub r2, r2, #(CFG_GBL_DATA_SIZE+8) @ set base 2 words into abort stack
318 ldmia r2, {r2 - r3} @ get pc, cpsr
319 add r0, sp, #S_FRAME_SIZE @ restore sp_SVC
323 stmia r5, {r0 - r3} @ save sp_SVC, lr_SVC, pc, cpsr
327 .macro irq_save_user_regs
328 sub sp, sp, #S_FRAME_SIZE
329 stmia sp, {r0 - r12} @ Calling r0-r12
331 stmdb r8, {sp, lr}^ @ Calling SP, LR
332 str lr, [r8, #0] @ Save calling PC
334 str r6, [r8, #4] @ Save CPSR
335 str r0, [r8, #8] @ Save OLD_R0
339 .macro irq_restore_user_regs
340 ldmia sp, {r0 - lr}^ @ Calling r0 - lr
342 ldr lr, [sp, #S_PC] @ Get PC
343 add sp, sp, #S_FRAME_SIZE
344 subs pc, lr, #4 @ return & move spsr_svc into cpsr
348 ldr r13, _armboot_start @ setup our mode stack
349 sub r13, r13, #(CONFIG_STACKSIZE+CFG_MALLOC_LEN)
350 sub r13, r13, #(CFG_GBL_DATA_SIZE+8) @ reserved a couple spots in abort stack
352 str lr, [r13] @ save caller lr / spsr
356 mov r13, #MODE_SVC @ prepare SVC-Mode
363 .macro get_irq_stack @ setup IRQ stack
364 ldr sp, IRQ_STACK_START
367 .macro get_fiq_stack @ setup FIQ stack
368 ldr sp, FIQ_STACK_START
375 undefined_instruction:
378 bl do_undefined_instruction
384 bl do_software_interrupt
404 #ifdef CONFIG_USE_IRQ
411 irq_restore_user_regs
416 /* someone ought to write a more effiction fiq_save_user_regs */
419 irq_restore_user_regs