summaryrefslogtreecommitdiff
path: root/arch/arm/cpu/pxa/start.S
blob: ae358a56e61f816d4c87930a022f07c5e7ba48e8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
/*
 *  armboot - Startup Code for XScale
 *
 *  Copyright (C) 1998	Dan Malek <dmalek@jlc.net>
 *  Copyright (C) 1999	Magnus Damm <kieraypc01.p.y.kie.era.ericsson.se>
 *  Copyright (C) 2000	Wolfgang Denk <wd@denx.de>
 *  Copyright (C) 2001	Alex Zuepke <azu@sysgo.de>
 *  Copyright (C) 2002	Kyle Harris <kharris@nexus-tech.net>
 *  Copyright (C) 2003	Robert Schwebel <r.schwebel@pengutronix.de>
 *  Copyright (C) 2003	Kai-Uwe Bloem <kai-uwe.bloem@auerswald.de>
 *  Copyright (c) 2010	Marek Vasut <marek.vasut@gmail.com>
 *
 * See file CREDITS for list of people who contributed to this
 * project.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307 USA
 */

#include <asm-offsets.h>
#include <config.h>
#include <version.h>
#include <asm/arch/pxa-regs.h>

/* takes care the CP15 update has taken place */
.macro CPWAIT reg
mrc  p15,0,\reg,c2,c0,0
mov  \reg,\reg
sub  pc,pc,#4
.endm

.globl _start
_start: b	reset
#ifdef CONFIG_PRELOADER
	ldr	pc, _hang
	ldr	pc, _hang
	ldr	pc, _hang
	ldr	pc, _hang
	ldr	pc, _hang
	ldr	pc, _hang
	ldr	pc, _hang

_hang:
	.word	do_hang
	.word	0x12345678
	.word	0x12345678
	.word	0x12345678
	.word	0x12345678
	.word	0x12345678
	.word	0x12345678
	.word	0x12345678	/* now 16*4=64 */
#else
	ldr	pc, _undefined_instruction
	ldr	pc, _software_interrupt
	ldr	pc, _prefetch_abort
	ldr	pc, _data_abort
	ldr	pc, _not_used
	ldr	pc, _irq
	ldr	pc, _fiq

_undefined_instruction: .word undefined_instruction
_software_interrupt:	.word software_interrupt
_prefetch_abort:	.word prefetch_abort
_data_abort:		.word data_abort
_not_used:		.word not_used
_irq:			.word irq
_fiq:			.word fiq
#endif	/* CONFIG_PRELOADER */

	.balignl 16,0xdeadbeef


/*
 * Startup Code (reset vector)
 *
 * do important init only if we don't start from RAM!
 * - relocate armboot to RAM
 * - setup stack
 * - jump to second stage
 */

.globl _TEXT_BASE
_TEXT_BASE:
	.word	CONFIG_SYS_TEXT_BASE

/*
 * These are defined in the board-specific linker script.
 */
.globl _bss_start_ofs
_bss_start_ofs:
	.word __bss_start - _start

.globl _bss_end_ofs
_bss_end_ofs:
	.word _end - _start

#ifdef CONFIG_USE_IRQ
/* IRQ stack memory (calculated at run-time) */
.globl IRQ_STACK_START
IRQ_STACK_START:
	.word	0x0badc0de

/* IRQ stack memory (calculated at run-time) */
.globl FIQ_STACK_START
FIQ_STACK_START:
	.word 0x0badc0de
#endif /* CONFIG_USE_IRQ */

#ifndef CONFIG_PRELOADER
/* IRQ stack memory (calculated at run-time) + 8 bytes */
.globl IRQ_STACK_START_IN
IRQ_STACK_START_IN:
	.word	0x0badc0de

/*
 * the actual reset code
 */

reset:
	/*
	 * set the cpu to SVC32 mode
	 */
	mrs	r0,cpsr
	bic	r0,r0,#0x1f
	orr	r0,r0,#0xd3
	msr	cpsr,r0

	/*
	 * Enable MMU to use DCache as DRAM
	 */
	/* Domain access -- enable for all CPs */
	ldr	r0, =0x0000ffff
	mcr	p15, 0, r0, c3, c0, 0

	/* Point TTBR to MMU table */
	ldr	r0, =mmu_table
	adr	r2, _start
	orr	r0, r2
	mcr	p15, 0, r0, c2, c0, 0

/* !!! Hereby, check if the code is running from SRAM !!! */
/* If the code is running from SRAM, alias SRAM to 0x0 to simulate NOR. The code
 * is linked to 0x0 too, so this makes things easier. */
	cmp	r2, #0x5c000000

	ldreq	r1, [r0]
	orreq	r1, r2
	streq	r1, [r0]

	/* Kick in MMU, ICache, DCache, BTB */
	mrc	p15, 0, r0, c1, c0, 0
	bic	r0, #0x1b00
	bic	r0, #0x0087
	orr	r0, #0x1800
	orr	r0, #0x0005
	mcr	p15, 0, r0, c1, c0, 0
	CPWAIT	r0

	/* Unlock Icache, Dcache */
	mcr	p15, 0, r0, c9, c1, 1
	mcr	p15, 0, r0, c9, c2, 1

	/* Flush Icache, Dcache, BTB */
	mcr	p15, 0, r0, c7, c7, 0

	/* Unlock I-TLB, D-TLB */
	mcr	p15, 0, r0, c10, c4, 1
	mcr	p15, 0, r0, c10, c8, 1

	/* Flush TLB */
	mcr	p15, 0, r0, c8, c7, 0
	/* Allocate 4096 bytes of Dcache as RAM */

	/* Drain pending loads and stores */
	mcr	p15, 0, r0, c7, c10, 4

	mov	r4, #0x00
	mov	r5, #0x00
	mov	r2, #0x01
	mcr	p15, 0, r0, c9, c2, 0
	CPWAIT	r0

	/* 128 lines reserved (128 x 32bytes = 4096 bytes total) */
	mov	r0, #128
	mov	r1, #0xa0000000
alloc:
	mcr	p15, 0, r1, c7, c2, 5
	/* Drain pending loads and stores */
	mcr	p15, 0, r0, c7, c10, 4
	strd	r4, [r1], #8
	strd	r4, [r1], #8
	strd	r4, [r1], #8
	strd	r4, [r1], #8
	subs	r0, #0x01
	bne	alloc
	/* Drain pending loads and stores */
	mcr	p15, 0, r0, c7, c10, 4
	mov	r2, #0x00
	mcr	p15, 0, r2, c9, c2, 0
	CPWAIT	r0

	/* Jump to 0x0 ( + offset) if running from SRAM */
	adr	r0, zerojmp
	bic	r0, #0x5c000000
	mov	pc, r0
zerojmp:

/* Set stackpointer in internal RAM to call board_init_f */
call_board_init_f:
	ldr	sp, =(CONFIG_SYS_INIT_SP_ADDR)
	ldr	r0,=0x00000000
	bl	board_init_f

/*------------------------------------------------------------------------------*/

/*
 * void relocate_code (addr_sp, gd, addr_moni)
 *
 * This "function" does not return, instead it continues in RAM
 * after relocating the monitor code.
 *
 */
	.globl	relocate_code
relocate_code:
	mov	r4, r0	/* save addr_sp */
	mov	r5, r1	/* save addr of gd */
	mov	r6, r2	/* save addr of destination */
	mov	r7, r2	/* save addr of destination */

	/* Set up the stack						    */
stack_setup:
	mov	sp, r4

	adr	r0, _start
	ldr	r2, _TEXT_BASE
	ldr	r3, _bss_start_ofs
	add	r2, r0, r3		/* r2 <- source end address	    */
	cmp	r0, r6
	beq	clear_bss

	stmfd sp!, {r0-r12}
copy_loop:
	ldmia	r0!, {r3-r5, r7-r11}	/* copy from source address [r0]    */
	stmia	r6!, {r3-r5, r7-r11}	/* copy to   target address [r1]    */
	cmp	r0, r2			/* until source end address [r2]    */
	blo	copy_loop
	ldmfd sp!, {r0-r12}

#ifndef CONFIG_PRELOADER
	/*
	 * fix .rel.dyn relocations
	 */
	ldr	r0, _TEXT_BASE		/* r0 <- Text base */
	sub	r9, r7, r0		/* r9 <- relocation offset */
	ldr	r10, _dynsym_start_ofs	/* r10 <- sym table ofs */
	add	r10, r10, r0		/* r10 <- sym table in FLASH */
	ldr	r2, _rel_dyn_start_ofs	/* r2 <- rel dyn start ofs */
	add	r2, r2, r0		/* r2 <- rel dyn start in FLASH */
	ldr	r3, _rel_dyn_end_ofs	/* r3 <- rel dyn end ofs */
	add	r3, r3, r0		/* r3 <- rel dyn end in FLASH */
fixloop:
	ldr	r0, [r2]	/* r0 <- location to fix up, IN FLASH! */
	add	r0, r9		/* r0 <- location to fix up in RAM */
	ldr	r1, [r2, #4]
	and	r8, r1, #0xff
	cmp	r8, #23		/* relative fixup? */
	beq	fixrel
	cmp	r8, #2		/* absolute fixup? */
	beq	fixabs
	/* ignore unknown type of fixup */
	b	fixnext
fixabs:
	/* absolute fix: set location to (offset) symbol value */
	mov	r1, r1, LSR #4		/* r1 <- symbol index in .dynsym */
	add	r1, r10, r1		/* r1 <- address of symbol in table */
	ldr	r1, [r1, #4]		/* r1 <- symbol value */
	add	r1, r9			/* r1 <- relocated sym addr */
	b	fixnext
fixrel:
	/* relative fix: increase location by offset */
	ldr	r1, [r0]
	add	r1, r1, r9
fixnext:
	str	r1, [r0]
	add	r2, r2, #8	/* each rel.dyn entry is 8 bytes */
	cmp	r2, r3
	blo	fixloop
#endif	/* #ifndef CONFIG_PRELOADER */

clear_bss:
#ifndef CONFIG_PRELOADER
	ldr	r0, _bss_start_ofs
	ldr	r1, _bss_end_ofs
	ldr	r3, _TEXT_BASE		/* Text base */
	mov	r4, r7			/* reloc addr */
	add	r0, r0, r4
	add	r1, r1, r4
	mov	r2, #0x00000000		/* clear			    */

clbss_l:str	r2, [r0]		/* clear loop...		    */
	add	r0, r0, #4
	cmp	r0, r1
	bne	clbss_l
#endif	/* #ifndef CONFIG_PRELOADER */

/*
 * We are done. Do not return, instead branch to second part of board
 * initialization, now running from RAM.
 */
#ifdef CONFIG_ONENAND_IPL
	ldr     r0, _start_oneboot_ofs
	mov	pc, r0

_start_oneboot_ofs
	: .word start_oneboot
#else
	ldr	r0, _board_init_r_ofs
	adr	r1, _start
	add	lr, r0, r1
	add	lr, lr, r9
	/* setup parameters for board_init_r */
	mov	r0, r5		/* gd_t */
	mov	r1, r7		/* dest_addr */
	/* jump to it ... */
	mov	pc, lr

_board_init_r_ofs:
	.word board_init_r - _start
#endif	/* CONFIG_ONENAND_IPL */

_rel_dyn_start_ofs:
	.word __rel_dyn_start - _start
_rel_dyn_end_ofs:
	.word __rel_dyn_end - _start
_dynsym_start_ofs:
	.word __dynsym_start - _start

#else /* CONFIG_PRELOADER */

/****************************************************************************/
/*									    */
/* the actual reset code for OneNAND IPL				    */
/*									    */
/****************************************************************************/

#ifndef	CONFIG_PXA27X
#error OneNAND IPL is not supported on PXA25x and 26x due to lack of SRAM
#endif

reset:
	/* Set CPU to SVC32 mode */
	mrs	r0,cpsr
	bic	r0,r0,#0x1f
	orr	r0,r0,#0x13
	msr	cpsr,r0

	/* Point stack at the end of SRAM and leave 32 words for abort-stack */
	ldr	sp, =0x5c03ff80

	/* Start OneNAND IPL */
	ldr	pc, =start_oneboot

#endif /* CONFIG_PRELOADER */

#ifndef CONFIG_PRELOADER
/****************************************************************************/
/*									    */
/* Interrupt handling							    */
/*									    */
/****************************************************************************/

/* IRQ stack frame							    */

#define S_FRAME_SIZE	72

#define S_OLD_R0	68
#define S_PSR		64
#define S_PC		60
#define S_LR		56
#define S_SP		52

#define S_IP		48
#define S_FP		44
#define S_R10		40
#define S_R9		36
#define S_R8		32
#define S_R7		28
#define S_R6		24
#define S_R5		20
#define S_R4		16
#define S_R3		12
#define S_R2		8
#define S_R1		4
#define S_R0		0

#define MODE_SVC 0x13

	/* use bad_save_user_regs for abort/prefetch/undef/swi ...	    */

	.macro	bad_save_user_regs
	sub	sp, sp, #S_FRAME_SIZE
	stmia	sp, {r0 - r12}			/* Calling r0-r12	    */
	add	r8, sp, #S_PC

	ldr	r2, IRQ_STACK_START_IN
	ldmia	r2, {r2 - r4}			/* get pc, cpsr, old_r0	    */
	add	r0, sp, #S_FRAME_SIZE		/* restore sp_SVC	    */

	add	r5, sp, #S_SP
	mov	r1, lr
	stmia	r5, {r0 - r4}			/* save sp_SVC, lr_SVC, pc, cpsr, old_r */
	mov	r0, sp
	.endm


	/* use irq_save_user_regs / irq_restore_user_regs for		     */
	/* IRQ/FIQ handling						     */

	.macro	irq_save_user_regs
	sub	sp, sp, #S_FRAME_SIZE
	stmia	sp, {r0 - r12}			/* Calling r0-r12	     */
	add	r8, sp, #S_PC
	stmdb	r8, {sp, lr}^			/* Calling SP, LR	     */
	str	lr, [r8, #0]			/* Save calling PC	     */
	mrs	r6, spsr
	str	r6, [r8, #4]			/* Save CPSR		     */
	str	r0, [r8, #8]			/* Save OLD_R0		     */
	mov	r0, sp
	.endm

	.macro	irq_restore_user_regs
	ldmia	sp, {r0 - lr}^			@ Calling r0 - lr
	mov	r0, r0
	ldr	lr, [sp, #S_PC]			@ Get PC
	add	sp, sp, #S_FRAME_SIZE
	subs	pc, lr, #4			@ return & move spsr_svc into cpsr
	.endm

	.macro get_bad_stack
	ldr	r13, IRQ_STACK_START_IN		@ setup our mode stack

	str	lr, [r13]			@ save caller lr / spsr
	mrs	lr, spsr
	str	lr, [r13, #4]

	mov	r13, #MODE_SVC			@ prepare SVC-Mode
	msr	spsr_c, r13
	mov	lr, pc
	movs	pc, lr
	.endm

	.macro get_irq_stack			@ setup IRQ stack
	ldr	sp, IRQ_STACK_START
	.endm

	.macro get_fiq_stack			@ setup FIQ stack
	ldr	sp, FIQ_STACK_START
	.endm
#endif	/* CONFIG_PRELOADER


/****************************************************************************/
/*									    */
/* exception handlers							    */
/*									    */
/****************************************************************************/

#ifdef CONFIG_PRELOADER
	.align	5
do_hang:
	ldr	sp, _TEXT_BASE			/* use 32 words abort stack */
	bl	hang				/* hang and never return */
#else
	.align	5
undefined_instruction:
	get_bad_stack
	bad_save_user_regs
	bl	do_undefined_instruction

	.align	5
software_interrupt:
	get_bad_stack
	bad_save_user_regs
	bl	do_software_interrupt

	.align	5
prefetch_abort:
	get_bad_stack
	bad_save_user_regs
	bl	do_prefetch_abort

	.align	5
data_abort:
	get_bad_stack
	bad_save_user_regs
	bl	do_data_abort

	.align	5
not_used:
	get_bad_stack
	bad_save_user_regs
	bl	do_not_used

#ifdef CONFIG_USE_IRQ

	.align	5
irq:
	get_irq_stack
	irq_save_user_regs
	bl	do_irq
	irq_restore_user_regs

	.align	5
fiq:
	get_fiq_stack
	irq_save_user_regs		/* someone ought to write a more    */
	bl	do_fiq			/* effiction fiq_save_user_regs	    */
	irq_restore_user_regs

#else /* !CONFIG_USE_IRQ */

	.align	5
irq:
	get_bad_stack
	bad_save_user_regs
	bl	do_irq

	.align	5
fiq:
	get_bad_stack
	bad_save_user_regs
	bl	do_fiq
#endif	/* CONFIG_PRELOADER */
#endif /* CONFIG_USE_IRQ */

/****************************************************************************/
/*									    */
/* Reset function: the PXA250 doesn't have a reset function, so we have to  */
/* perform a watchdog timeout for a soft reset.				    */
/*									    */
/****************************************************************************/
/* Operating System Timer */
.align	5
.globl reset_cpu

	/* FIXME: this code is PXA250 specific. How is this handled on	    */
	/*	  other XScale processors?				    */

reset_cpu:

	/* We set OWE:WME (watchdog enable) and wait until timeout happens  */

	ldr	r0, =OWER
	ldr	r1, [r0]
	orr	r1, r1, #0x0001			/* bit0: WME		    */
	str	r1, [r0]

	/* OS timer does only wrap every 1165 seconds, so we have to set    */
	/* the match register as well.					    */

	ldr	r0, =OSCR
	ldr	r1, [r0]			/* read OS timer	    */
	add	r1, r1, #0x800			/* let OSMR3 match after    */
	add	r1, r1, #0x800			/* 4096*(1/3.6864MHz)=1ms   */
	ldr	r0, =OSMR3
	str	r1, [r0]

reset_endless:

	b	reset_endless

#ifndef CONFIG_PRELOADER
.section .mmudata, "a"
	.align	14
	.globl	mmu_table
mmu_table:
	/* 0x00000000 - 0xa0000000 : 1:1, uncached mapping */
	.set	__base, 0
	.rept	0xa00
	.word	(__base << 20) | 0xc12
	.set	__base, __base + 1
	.endr

	/* 0xa0000000 - 0xa0100000 : 1:1, cached mapping */
	.word	(0xa00 << 20) | 0x1c1e

	.set	__base, 0xa01
	.rept	0x1000 - 0xa01
	.word	(__base << 20) | 0xc12
	.set	__base, __base + 1
	.endr
#endif	/* CONFIG_PRELOADER */