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wdenkf39748a2004-06-09 13:37:52 +00001/*
2 * armboot - Startup Code for ARM920 CPU-core
3 *
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>
7 *
8 * See file CREDITS for list of people who contributed to this
9 * project.
10 *
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.
15 *
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.
20 *
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,
24 * MA 02111-1307 USA
25 */
26
27
28#include <config.h>
29#include <version.h>
30
31
32/*
33 *************************************************************************
34 *
35 * Jump vector table as in table 3.1 in [1]
36 *
37 *************************************************************************
38 */
39
40
41.globl _start
42_start: b reset
43 ldr pc, _undefined_instruction
44 ldr pc, _software_interrupt
45 ldr pc, _prefetch_abort
46 ldr pc, _data_abort
47 ldr pc, _not_used
48 ldr pc, _irq
49 ldr pc, _fiq
50
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
56_irq: .word irq
57_fiq: .word fiq
58
59 .balignl 16,0xdeadbeef
60
61
62/*
63 *************************************************************************
64 *
65 * Startup Code (reset vector)
66 *
67 * do important init only if we don't start from memory!
68 * relocate armboot to ram
69 * setup stack
70 * jump to second stage
71 *
72 *************************************************************************
73 */
74
75_TEXT_BASE:
76 .word TEXT_BASE
77
78.globl _armboot_start
79_armboot_start:
80 .word _start
81
82/*
83 * These are defined in the board-specific linker script.
84 */
85.globl _bss_start
86_bss_start:
87 .word __bss_start
88
89.globl _bss_end
90_bss_end:
91 .word _end
92
93#ifdef CONFIG_USE_IRQ
94/* IRQ stack memory (calculated at run-time) */
95.globl IRQ_STACK_START
96IRQ_STACK_START:
97 .word 0x0badc0de
98
99/* IRQ stack memory (calculated at run-time) */
100.globl FIQ_STACK_START
101FIQ_STACK_START:
102 .word 0x0badc0de
103#endif
104
105
106/*
107 * the actual reset code
108 */
109
110reset:
111 /*
112 * set the cpu to SVC32 mode
113 */
114 mrs r0,cpsr
115 bic r0,r0,#0x1f
116 orr r0,r0,#0xd3
117 msr cpsr,r0
118
119#define pWDTCTL 0x80001400 /* Watchdog Timer control register */
120#define pINTENC 0x8000050C /* Interupt-Controller enable clear register */
121#define pCLKSET 0x80000420 /* clock divisor register */
122
123 /* disable watchdog, set watchdog control register to
124 * all zeros (default reset)
125 */
126 ldr r0, =pWDTCTL
127 mov r1, #0x0
128 str r1, [r0]
129
130 /*
131 * mask all IRQs by setting all bits in the INTENC register (default)
132 */
133 mov r1, #0xffffffff
134 ldr r0, =pINTENC
135 str r1, [r0]
136
137 /* FCLK:HCLK:PCLK = 1:2:2 */
138 /* default FCLK is 200 MHz, using 14.7456 MHz fin */
139 ldr r0, =pCLKSET
140 ldr r1, =0x0004ee39
141@ ldr r1, =0x0005ee39 @ 1: 2: 4
142 str r1, [r0]
143
144 /*
145 * we do sys-critical inits only at reboot,
146 * not when booting from ram!
147 */
wdenk8aa1a2d2005-04-04 12:44:11 +0000148#ifndef CONFIG_SKIP_LOWLEVEL_INIT
wdenkf39748a2004-06-09 13:37:52 +0000149 bl cpu_init_crit
150#endif
151
wdenk8aa1a2d2005-04-04 12:44:11 +0000152#ifndef CONFIG_SKIP_RELOCATE_UBOOT
wdenkf39748a2004-06-09 13:37:52 +0000153relocate: /* relocate U-Boot to RAM */
154 adr r0, _start /* r0 <- current position of code */
155 ldr r1, _TEXT_BASE /* test if we run from flash or RAM */
156 cmp r0, r1 /* don't reloc during debug */
157 beq stack_setup
158
159 ldr r2, _armboot_start
160 ldr r3, _bss_start
161 sub r2, r3, r2 /* r2 <- size of armboot */
162 add r2, r0, r2 /* r2 <- source end address */
163
164copy_loop:
165 ldmia r0!, {r3-r10} /* copy from source address [r0] */
166 stmia r1!, {r3-r10} /* copy to target address [r1] */
167 cmp r0, r2 /* until source end addreee [r2] */
168 blt copy_loop /* a 'ble' here actually copies */
169 /* four bytes of bss */
wdenk8aa1a2d2005-04-04 12:44:11 +0000170#endif /* CONFIG_SKIP_RELOCATE_UBOOT */
wdenkf39748a2004-06-09 13:37:52 +0000171
172 /* Set up the stack */
173stack_setup:
174 ldr r0, _TEXT_BASE /* upper 128 KiB: relocated uboot */
175 sub r0, r0, #CFG_MALLOC_LEN /* malloc area */
176 sub r0, r0, #CFG_GBL_DATA_SIZE /* bdinfo */
177#ifdef CONFIG_USE_IRQ
178 sub r0, r0, #(CONFIG_STACKSIZE_IRQ+CONFIG_STACKSIZE_FIQ)
179#endif
180 sub sp, r0, #12 /* leave 3 words for abort-stack */
181
182clear_bss:
183 ldr r0, _bss_start /* find start of bss segment */
184 @add r0, r0, #4 /* start at first byte of bss */
185 /* why inc. 4 bytes past then? */
186 ldr r1, _bss_end /* stop here */
Wolfgang Denk53677ef2008-05-20 16:00:29 +0200187 mov r2, #0x00000000 /* clear */
wdenkf39748a2004-06-09 13:37:52 +0000188
189clbss_l:str r2, [r0] /* clear loop... */
190 add r0, r0, #4
191 cmp r0, r1
wdenka1191902005-01-09 17:12:27 +0000192 ble clbss_l
wdenkf39748a2004-06-09 13:37:52 +0000193
194 ldr pc, _start_armboot
195
196_start_armboot: .word start_armboot
197
198
199/*
200 *************************************************************************
201 *
202 * CPU_init_critical registers
203 *
204 * setup important registers
205 * setup memory timing
206 *
207 *************************************************************************
208 */
209
210
211cpu_init_crit:
212 /*
213 * flush v4 I/D caches
214 */
215 mov r0, #0
216 mcr p15, 0, r0, c7, c7, 0 /* flush v3/v4 cache */
217 mcr p15, 0, r0, c8, c7, 0 /* flush v4 TLB */
218
219 /*
220 * disable MMU stuff and caches
221 */
222 mrc p15, 0, r0, c1, c0, 0
223 bic r0, r0, #0x00002300 @ clear bits 13, 9:8 (--V- --RS)
224 bic r0, r0, #0x00000087 @ clear bits 7, 2:0 (B--- -CAM)
225 orr r0, r0, #0x00000002 @ set bit 2 (A) Align
226 orr r0, r0, #0x00001000 @ set bit 12 (I) I-Cache
227 orr r0, r0, #0x40000000 @ set bit 30 (nF) notFastBus
228 mcr p15, 0, r0, c1, c0, 0
229
230
231 /*
232 * before relocating, we have to setup RAM timing
233 * because memory timing is board-dependend, you will
wdenk400558b2005-04-02 23:52:25 +0000234 * find a lowlevel_init.S in your board directory.
wdenkf39748a2004-06-09 13:37:52 +0000235 */
236 mov ip, lr
wdenk400558b2005-04-02 23:52:25 +0000237 bl lowlevel_init
wdenkf39748a2004-06-09 13:37:52 +0000238 mov lr, ip
239
240 mov pc, lr
241
242
243/*
244 *************************************************************************
245 *
246 * Interrupt handling
247 *
248 *************************************************************************
249 */
250
251@
252@ IRQ stack frame.
253@
254#define S_FRAME_SIZE 72
255
256#define S_OLD_R0 68
257#define S_PSR 64
258#define S_PC 60
259#define S_LR 56
260#define S_SP 52
261
262#define S_IP 48
263#define S_FP 44
264#define S_R10 40
265#define S_R9 36
266#define S_R8 32
267#define S_R7 28
268#define S_R6 24
269#define S_R5 20
270#define S_R4 16
271#define S_R3 12
272#define S_R2 8
273#define S_R1 4
274#define S_R0 0
275
276#define MODE_SVC 0x13
277#define I_BIT 0x80
278
279/*
280 * use bad_save_user_regs for abort/prefetch/undef/swi ...
281 * use irq_save_user_regs / irq_restore_user_regs for IRQ/FIQ handling
282 */
283
284 .macro bad_save_user_regs
285 sub sp, sp, #S_FRAME_SIZE
286 stmia sp, {r0 - r12} @ Calling r0-r12
287 ldr r2, _armboot_start
288 sub r2, r2, #(CONFIG_STACKSIZE+CFG_MALLOC_LEN)
289 sub r2, r2, #(CFG_GBL_DATA_SIZE+8) @ set base 2 words into abort stack
290 ldmia r2, {r2 - r3} @ get pc, cpsr
291 add r0, sp, #S_FRAME_SIZE @ restore sp_SVC
292
293 add r5, sp, #S_SP
294 mov r1, lr
295 stmia r5, {r0 - r3} @ save sp_SVC, lr_SVC, pc, cpsr
296 mov r0, sp
297 .endm
298
299 .macro irq_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 stmdb r8, {sp, lr}^ @ Calling SP, LR
304 str lr, [r8, #0] @ Save calling PC
305 mrs r6, spsr
306 str r6, [r8, #4] @ Save CPSR
307 str r0, [r8, #8] @ Save OLD_R0
308 mov r0, sp
309 .endm
310
311 .macro irq_restore_user_regs
312 ldmia sp, {r0 - lr}^ @ Calling r0 - lr
313 mov r0, r0
314 ldr lr, [sp, #S_PC] @ Get PC
315 add sp, sp, #S_FRAME_SIZE
316 subs pc, lr, #4 @ return & move spsr_svc into cpsr
317 .endm
318
319 .macro get_bad_stack
320 ldr r13, _armboot_start @ setup our mode stack
321 sub r13, r13, #(CONFIG_STACKSIZE+CFG_MALLOC_LEN)
322 sub r13, r13, #(CFG_GBL_DATA_SIZE+8) @ reserved a couple spots in abort stack
323
324 str lr, [r13] @ save caller lr / spsr
325 mrs lr, spsr
326 str lr, [r13, #4]
327
328 mov r13, #MODE_SVC @ prepare SVC-Mode
329 @ msr spsr_c, r13
330 msr spsr, r13
331 mov lr, pc
332 movs pc, lr
333 .endm
334
335 .macro get_irq_stack @ setup IRQ stack
336 ldr sp, IRQ_STACK_START
337 .endm
338
339 .macro get_fiq_stack @ setup FIQ stack
340 ldr sp, FIQ_STACK_START
341 .endm
342
343/*
344 * exception handlers
345 */
346 .align 5
347undefined_instruction:
348 get_bad_stack
349 bad_save_user_regs
Wolfgang Denk53677ef2008-05-20 16:00:29 +0200350 bl do_undefined_instruction
wdenkf39748a2004-06-09 13:37:52 +0000351
352 .align 5
353software_interrupt:
354 get_bad_stack
355 bad_save_user_regs
Wolfgang Denk53677ef2008-05-20 16:00:29 +0200356 bl do_software_interrupt
wdenkf39748a2004-06-09 13:37:52 +0000357
358 .align 5
359prefetch_abort:
360 get_bad_stack
361 bad_save_user_regs
Wolfgang Denk53677ef2008-05-20 16:00:29 +0200362 bl do_prefetch_abort
wdenkf39748a2004-06-09 13:37:52 +0000363
364 .align 5
365data_abort:
366 get_bad_stack
367 bad_save_user_regs
Wolfgang Denk53677ef2008-05-20 16:00:29 +0200368 bl do_data_abort
wdenkf39748a2004-06-09 13:37:52 +0000369
370 .align 5
371not_used:
372 get_bad_stack
373 bad_save_user_regs
Wolfgang Denk53677ef2008-05-20 16:00:29 +0200374 bl do_not_used
wdenkf39748a2004-06-09 13:37:52 +0000375
376#ifdef CONFIG_USE_IRQ
377
378 .align 5
379irq:
380 get_irq_stack
381 irq_save_user_regs
Wolfgang Denk53677ef2008-05-20 16:00:29 +0200382 bl do_irq
wdenkf39748a2004-06-09 13:37:52 +0000383 irq_restore_user_regs
384
385 .align 5
386fiq:
387 get_fiq_stack
388 /* someone ought to write a more effiction fiq_save_user_regs */
389 irq_save_user_regs
Wolfgang Denk53677ef2008-05-20 16:00:29 +0200390 bl do_fiq
wdenkf39748a2004-06-09 13:37:52 +0000391 irq_restore_user_regs
392
393#else
394
395 .align 5
396irq:
397 get_bad_stack
398 bad_save_user_regs
Wolfgang Denk53677ef2008-05-20 16:00:29 +0200399 bl do_irq
wdenkf39748a2004-06-09 13:37:52 +0000400
401 .align 5
402fiq:
403 get_bad_stack
404 bad_save_user_regs
Wolfgang Denk53677ef2008-05-20 16:00:29 +0200405 bl do_fiq
wdenkf39748a2004-06-09 13:37:52 +0000406
407#endif
408
409 .align 5
410.globl reset_cpu
411reset_cpu:
412 bl disable_interrupts
413
414 /* Disable watchdog */
415 ldr r1, =pWDTCTL
416 mov r3, #0
417 str r3, [r1]
418
419 /* reset counter */
420 ldr r3, =0x00001984
421 str r3, [r1, #4]
422
423 /* Enable the watchdog */
424 mov r3, #1
425 str r3, [r1]
426
427_loop_forever:
428 b _loop_forever