xref: /openbmc/u-boot/arch/arm/cpu/pxa/start.S (revision 9b107e6138e719ea5a0b924862a9b109c020c7ac)
1/*
2 *  armboot - Startup Code for XScale
3 *
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 Zuepke <azu@sysgo.de>
8 *  Copyright (C) 2002	Kyle Harris <kharris@nexus-tech.net>
9 *  Copyright (C) 2003	Robert Schwebel <r.schwebel@pengutronix.de>
10 *  Copyright (C) 2003	Kai-Uwe Bloem <kai-uwe.bloem@auerswald.de>
11 *  Copyright (c) 2010	Marek Vasut <marek.vasut@gmail.com>
12 *
13 * See file CREDITS for list of people who contributed to this
14 * project.
15 *
16 * This program is free software; you can redistribute it and/or
17 * modify it under the terms of the GNU General Public License as
18 * published by the Free Software Foundation; either version 2 of
19 * the License, or (at your option) any later version.
20 *
21 * This program is distributed in the hope that it will be useful,
22 * but WITHOUT ANY WARRANTY; without even the implied warranty of
23 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the
24 * GNU General Public License for more details.
25 *
26 * You should have received a copy of the GNU General Public License
27 * along with this program; if not, write to the Free Software
28 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
29 * MA 02111-1307 USA
30 */
31
32#include <asm-offsets.h>
33#include <config.h>
34#include <version.h>
35#include <asm/arch/pxa-regs.h>
36
37/* takes care the CP15 update has taken place */
38.macro CPWAIT reg
39mrc  p15,0,\reg,c2,c0,0
40mov  \reg,\reg
41sub  pc,pc,#4
42.endm
43
44.globl _start
45_start: b	reset
46#ifdef CONFIG_PRELOADER
47	ldr	pc, _hang
48	ldr	pc, _hang
49	ldr	pc, _hang
50	ldr	pc, _hang
51	ldr	pc, _hang
52	ldr	pc, _hang
53	ldr	pc, _hang
54
55_hang:
56	.word	do_hang
57	.word	0x12345678
58	.word	0x12345678
59	.word	0x12345678
60	.word	0x12345678
61	.word	0x12345678
62	.word	0x12345678
63	.word	0x12345678	/* now 16*4=64 */
64#else
65	ldr	pc, _undefined_instruction
66	ldr	pc, _software_interrupt
67	ldr	pc, _prefetch_abort
68	ldr	pc, _data_abort
69	ldr	pc, _not_used
70	ldr	pc, _irq
71	ldr	pc, _fiq
72
73_undefined_instruction: .word undefined_instruction
74_software_interrupt:	.word software_interrupt
75_prefetch_abort:	.word prefetch_abort
76_data_abort:		.word data_abort
77_not_used:		.word not_used
78_irq:			.word irq
79_fiq:			.word fiq
80#endif	/* CONFIG_PRELOADER */
81
82	.balignl 16,0xdeadbeef
83
84
85/*
86 * Startup Code (reset vector)
87 *
88 * do important init only if we don't start from RAM!
89 * - relocate armboot to RAM
90 * - setup stack
91 * - jump to second stage
92 */
93
94.globl _TEXT_BASE
95_TEXT_BASE:
96	.word	CONFIG_SYS_TEXT_BASE
97
98/*
99 * These are defined in the board-specific linker script.
100 */
101.globl _bss_start_ofs
102_bss_start_ofs:
103	.word __bss_start - _start
104
105.globl _bss_end_ofs
106_bss_end_ofs:
107	.word _end - _start
108
109#ifdef CONFIG_USE_IRQ
110/* IRQ stack memory (calculated at run-time) */
111.globl IRQ_STACK_START
112IRQ_STACK_START:
113	.word	0x0badc0de
114
115/* IRQ stack memory (calculated at run-time) */
116.globl FIQ_STACK_START
117FIQ_STACK_START:
118	.word 0x0badc0de
119#endif /* CONFIG_USE_IRQ */
120
121#ifndef CONFIG_PRELOADER
122/* IRQ stack memory (calculated at run-time) + 8 bytes */
123.globl IRQ_STACK_START_IN
124IRQ_STACK_START_IN:
125	.word	0x0badc0de
126
127/*
128 * the actual reset code
129 */
130
131reset:
132	/*
133	 * set the cpu to SVC32 mode
134	 */
135	mrs	r0,cpsr
136	bic	r0,r0,#0x1f
137	orr	r0,r0,#0xd3
138	msr	cpsr,r0
139
140	/*
141	 * Enable MMU to use DCache as DRAM
142	 */
143	/* Domain access -- enable for all CPs */
144	ldr	r0, =0x0000ffff
145	mcr	p15, 0, r0, c3, c0, 0
146
147	/* Point TTBR to MMU table */
148	ldr	r0, =mmu_table
149	adr	r2, _start
150	orr	r0, r2
151	mcr	p15, 0, r0, c2, c0, 0
152
153/* !!! Hereby, check if the code is running from SRAM !!! */
154/* If the code is running from SRAM, alias SRAM to 0x0 to simulate NOR. The code
155 * is linked to 0x0 too, so this makes things easier. */
156	cmp	r2, #0x5c000000
157
158	ldreq	r1, [r0]
159	orreq	r1, r2
160	streq	r1, [r0]
161
162	/* Kick in MMU, ICache, DCache, BTB */
163	mrc	p15, 0, r0, c1, c0, 0
164	bic	r0, #0x1b00
165	bic	r0, #0x0087
166	orr	r0, #0x1800
167	orr	r0, #0x0005
168	mcr	p15, 0, r0, c1, c0, 0
169	CPWAIT	r0
170
171	/* Unlock Icache, Dcache */
172	mcr	p15, 0, r0, c9, c1, 1
173	mcr	p15, 0, r0, c9, c2, 1
174
175	/* Flush Icache, Dcache, BTB */
176	mcr	p15, 0, r0, c7, c7, 0
177
178	/* Unlock I-TLB, D-TLB */
179	mcr	p15, 0, r0, c10, c4, 1
180	mcr	p15, 0, r0, c10, c8, 1
181
182	/* Flush TLB */
183	mcr	p15, 0, r0, c8, c7, 0
184	/* Allocate 4096 bytes of Dcache as RAM */
185
186	/* Drain pending loads and stores */
187	mcr	p15, 0, r0, c7, c10, 4
188
189	mov	r4, #0x00
190	mov	r5, #0x00
191	mov	r2, #0x01
192	mcr	p15, 0, r0, c9, c2, 0
193	CPWAIT	r0
194
195	/* 128 lines reserved (128 x 32bytes = 4096 bytes total) */
196	mov	r0, #128
197	mov	r1, #0xa0000000
198alloc:
199	mcr	p15, 0, r1, c7, c2, 5
200	/* Drain pending loads and stores */
201	mcr	p15, 0, r0, c7, c10, 4
202	strd	r4, [r1], #8
203	strd	r4, [r1], #8
204	strd	r4, [r1], #8
205	strd	r4, [r1], #8
206	subs	r0, #0x01
207	bne	alloc
208	/* Drain pending loads and stores */
209	mcr	p15, 0, r0, c7, c10, 4
210	mov	r2, #0x00
211	mcr	p15, 0, r2, c9, c2, 0
212	CPWAIT	r0
213
214	/* Jump to 0x0 ( + offset) if running from SRAM */
215	adr	r0, zerojmp
216	bic	r0, #0x5c000000
217	mov	pc, r0
218zerojmp:
219
220/* Set stackpointer in internal RAM to call board_init_f */
221call_board_init_f:
222	ldr	sp, =(CONFIG_SYS_INIT_SP_ADDR)
223	ldr	r0,=0x00000000
224	bl	board_init_f
225
226/*------------------------------------------------------------------------------*/
227
228/*
229 * void relocate_code (addr_sp, gd, addr_moni)
230 *
231 * This "function" does not return, instead it continues in RAM
232 * after relocating the monitor code.
233 *
234 */
235	.globl	relocate_code
236relocate_code:
237	mov	r4, r0	/* save addr_sp */
238	mov	r5, r1	/* save addr of gd */
239	mov	r6, r2	/* save addr of destination */
240	mov	r7, r2	/* save addr of destination */
241
242	/* Set up the stack						    */
243stack_setup:
244	mov	sp, r4
245
246	adr	r0, _start
247	ldr	r2, _TEXT_BASE
248	ldr	r3, _bss_start_ofs
249	add	r2, r0, r3		/* r2 <- source end address	    */
250	cmp	r0, r6
251	beq	clear_bss
252
253	stmfd sp!, {r0-r12}
254copy_loop:
255	ldmia	r0!, {r3-r5, r7-r11}	/* copy from source address [r0]    */
256	stmia	r6!, {r3-r5, r7-r11}	/* copy to   target address [r1]    */
257	cmp	r0, r2			/* until source end address [r2]    */
258	blo	copy_loop
259	ldmfd sp!, {r0-r12}
260
261#ifndef CONFIG_PRELOADER
262	/*
263	 * fix .rel.dyn relocations
264	 */
265	ldr	r0, _TEXT_BASE		/* r0 <- Text base */
266	sub	r9, r7, r0		/* r9 <- relocation offset */
267	ldr	r10, _dynsym_start_ofs	/* r10 <- sym table ofs */
268	add	r10, r10, r0		/* r10 <- sym table in FLASH */
269	ldr	r2, _rel_dyn_start_ofs	/* r2 <- rel dyn start ofs */
270	add	r2, r2, r0		/* r2 <- rel dyn start in FLASH */
271	ldr	r3, _rel_dyn_end_ofs	/* r3 <- rel dyn end ofs */
272	add	r3, r3, r0		/* r3 <- rel dyn end in FLASH */
273fixloop:
274	ldr	r0, [r2]	/* r0 <- location to fix up, IN FLASH! */
275	add	r0, r9		/* r0 <- location to fix up in RAM */
276	ldr	r1, [r2, #4]
277	and	r8, r1, #0xff
278	cmp	r8, #23		/* relative fixup? */
279	beq	fixrel
280	cmp	r8, #2		/* absolute fixup? */
281	beq	fixabs
282	/* ignore unknown type of fixup */
283	b	fixnext
284fixabs:
285	/* absolute fix: set location to (offset) symbol value */
286	mov	r1, r1, LSR #4		/* r1 <- symbol index in .dynsym */
287	add	r1, r10, r1		/* r1 <- address of symbol in table */
288	ldr	r1, [r1, #4]		/* r1 <- symbol value */
289	add	r1, r9			/* r1 <- relocated sym addr */
290	b	fixnext
291fixrel:
292	/* relative fix: increase location by offset */
293	ldr	r1, [r0]
294	add	r1, r1, r9
295fixnext:
296	str	r1, [r0]
297	add	r2, r2, #8	/* each rel.dyn entry is 8 bytes */
298	cmp	r2, r3
299	blo	fixloop
300#endif	/* #ifndef CONFIG_PRELOADER */
301
302clear_bss:
303#ifndef CONFIG_PRELOADER
304	ldr	r0, _bss_start_ofs
305	ldr	r1, _bss_end_ofs
306	ldr	r3, _TEXT_BASE		/* Text base */
307	mov	r4, r7			/* reloc addr */
308	add	r0, r0, r4
309	add	r1, r1, r4
310	mov	r2, #0x00000000		/* clear			    */
311
312clbss_l:str	r2, [r0]		/* clear loop...		    */
313	add	r0, r0, #4
314	cmp	r0, r1
315	bne	clbss_l
316#endif	/* #ifndef CONFIG_PRELOADER */
317
318/*
319 * We are done. Do not return, instead branch to second part of board
320 * initialization, now running from RAM.
321 */
322#ifdef CONFIG_ONENAND_IPL
323	ldr     r0, _start_oneboot_ofs
324	mov	pc, r0
325
326_start_oneboot_ofs
327	: .word start_oneboot
328#else
329	ldr	r0, _board_init_r_ofs
330	adr	r1, _start
331	add	lr, r0, r1
332	add	lr, lr, r9
333	/* setup parameters for board_init_r */
334	mov	r0, r5		/* gd_t */
335	mov	r1, r7		/* dest_addr */
336	/* jump to it ... */
337	mov	pc, lr
338
339_board_init_r_ofs:
340	.word board_init_r - _start
341#endif	/* CONFIG_ONENAND_IPL */
342
343_rel_dyn_start_ofs:
344	.word __rel_dyn_start - _start
345_rel_dyn_end_ofs:
346	.word __rel_dyn_end - _start
347_dynsym_start_ofs:
348	.word __dynsym_start - _start
349
350#else /* CONFIG_PRELOADER */
351
352/****************************************************************************/
353/*									    */
354/* the actual reset code for OneNAND IPL				    */
355/*									    */
356/****************************************************************************/
357
358#ifndef	CONFIG_PXA27X
359#error OneNAND IPL is not supported on PXA25x and 26x due to lack of SRAM
360#endif
361
362reset:
363	/* Set CPU to SVC32 mode */
364	mrs	r0,cpsr
365	bic	r0,r0,#0x1f
366	orr	r0,r0,#0x13
367	msr	cpsr,r0
368
369	/* Point stack at the end of SRAM and leave 32 words for abort-stack */
370	ldr	sp, =0x5c03ff80
371
372	/* Start OneNAND IPL */
373	ldr	pc, =start_oneboot
374
375#endif /* CONFIG_PRELOADER */
376
377#ifndef CONFIG_PRELOADER
378/****************************************************************************/
379/*									    */
380/* Interrupt handling							    */
381/*									    */
382/****************************************************************************/
383
384/* IRQ stack frame							    */
385
386#define S_FRAME_SIZE	72
387
388#define S_OLD_R0	68
389#define S_PSR		64
390#define S_PC		60
391#define S_LR		56
392#define S_SP		52
393
394#define S_IP		48
395#define S_FP		44
396#define S_R10		40
397#define S_R9		36
398#define S_R8		32
399#define S_R7		28
400#define S_R6		24
401#define S_R5		20
402#define S_R4		16
403#define S_R3		12
404#define S_R2		8
405#define S_R1		4
406#define S_R0		0
407
408#define MODE_SVC 0x13
409
410	/* use bad_save_user_regs for abort/prefetch/undef/swi ...	    */
411
412	.macro	bad_save_user_regs
413	sub	sp, sp, #S_FRAME_SIZE
414	stmia	sp, {r0 - r12}			/* Calling r0-r12	    */
415	add	r8, sp, #S_PC
416
417	ldr	r2, IRQ_STACK_START_IN
418	ldmia	r2, {r2 - r4}			/* get pc, cpsr, old_r0	    */
419	add	r0, sp, #S_FRAME_SIZE		/* restore sp_SVC	    */
420
421	add	r5, sp, #S_SP
422	mov	r1, lr
423	stmia	r5, {r0 - r4}			/* save sp_SVC, lr_SVC, pc, cpsr, old_r */
424	mov	r0, sp
425	.endm
426
427
428	/* use irq_save_user_regs / irq_restore_user_regs for		     */
429	/* IRQ/FIQ handling						     */
430
431	.macro	irq_save_user_regs
432	sub	sp, sp, #S_FRAME_SIZE
433	stmia	sp, {r0 - r12}			/* Calling r0-r12	     */
434	add	r8, sp, #S_PC
435	stmdb	r8, {sp, lr}^			/* Calling SP, LR	     */
436	str	lr, [r8, #0]			/* Save calling PC	     */
437	mrs	r6, spsr
438	str	r6, [r8, #4]			/* Save CPSR		     */
439	str	r0, [r8, #8]			/* Save OLD_R0		     */
440	mov	r0, sp
441	.endm
442
443	.macro	irq_restore_user_regs
444	ldmia	sp, {r0 - lr}^			@ Calling r0 - lr
445	mov	r0, r0
446	ldr	lr, [sp, #S_PC]			@ Get PC
447	add	sp, sp, #S_FRAME_SIZE
448	subs	pc, lr, #4			@ return & move spsr_svc into cpsr
449	.endm
450
451	.macro get_bad_stack
452	ldr	r13, IRQ_STACK_START_IN		@ setup our mode stack
453
454	str	lr, [r13]			@ save caller lr / spsr
455	mrs	lr, spsr
456	str	lr, [r13, #4]
457
458	mov	r13, #MODE_SVC			@ prepare SVC-Mode
459	msr	spsr_c, r13
460	mov	lr, pc
461	movs	pc, lr
462	.endm
463
464	.macro get_irq_stack			@ setup IRQ stack
465	ldr	sp, IRQ_STACK_START
466	.endm
467
468	.macro get_fiq_stack			@ setup FIQ stack
469	ldr	sp, FIQ_STACK_START
470	.endm
471#endif	/* CONFIG_PRELOADER
472
473
474/****************************************************************************/
475/*									    */
476/* exception handlers							    */
477/*									    */
478/****************************************************************************/
479
480#ifdef CONFIG_PRELOADER
481	.align	5
482do_hang:
483	ldr	sp, _TEXT_BASE			/* use 32 words abort stack */
484	bl	hang				/* hang and never return */
485#else
486	.align	5
487undefined_instruction:
488	get_bad_stack
489	bad_save_user_regs
490	bl	do_undefined_instruction
491
492	.align	5
493software_interrupt:
494	get_bad_stack
495	bad_save_user_regs
496	bl	do_software_interrupt
497
498	.align	5
499prefetch_abort:
500	get_bad_stack
501	bad_save_user_regs
502	bl	do_prefetch_abort
503
504	.align	5
505data_abort:
506	get_bad_stack
507	bad_save_user_regs
508	bl	do_data_abort
509
510	.align	5
511not_used:
512	get_bad_stack
513	bad_save_user_regs
514	bl	do_not_used
515
516#ifdef CONFIG_USE_IRQ
517
518	.align	5
519irq:
520	get_irq_stack
521	irq_save_user_regs
522	bl	do_irq
523	irq_restore_user_regs
524
525	.align	5
526fiq:
527	get_fiq_stack
528	irq_save_user_regs		/* someone ought to write a more    */
529	bl	do_fiq			/* effiction fiq_save_user_regs	    */
530	irq_restore_user_regs
531
532#else /* !CONFIG_USE_IRQ */
533
534	.align	5
535irq:
536	get_bad_stack
537	bad_save_user_regs
538	bl	do_irq
539
540	.align	5
541fiq:
542	get_bad_stack
543	bad_save_user_regs
544	bl	do_fiq
545#endif	/* CONFIG_PRELOADER */
546#endif /* CONFIG_USE_IRQ */
547
548/****************************************************************************/
549/*									    */
550/* Reset function: the PXA250 doesn't have a reset function, so we have to  */
551/* perform a watchdog timeout for a soft reset.				    */
552/*									    */
553/****************************************************************************/
554/* Operating System Timer */
555.align	5
556.globl reset_cpu
557
558	/* FIXME: this code is PXA250 specific. How is this handled on	    */
559	/*	  other XScale processors?				    */
560
561reset_cpu:
562
563	/* We set OWE:WME (watchdog enable) and wait until timeout happens  */
564
565	ldr	r0, =OWER
566	ldr	r1, [r0]
567	orr	r1, r1, #0x0001			/* bit0: WME		    */
568	str	r1, [r0]
569
570	/* OS timer does only wrap every 1165 seconds, so we have to set    */
571	/* the match register as well.					    */
572
573	ldr	r0, =OSCR
574	ldr	r1, [r0]			/* read OS timer	    */
575	add	r1, r1, #0x800			/* let OSMR3 match after    */
576	add	r1, r1, #0x800			/* 4096*(1/3.6864MHz)=1ms   */
577	ldr	r0, =OSMR3
578	str	r1, [r0]
579
580reset_endless:
581
582	b	reset_endless
583
584#ifndef CONFIG_PRELOADER
585.section .mmudata, "a"
586	.align	14
587	.globl	mmu_table
588mmu_table:
589	/* 0x00000000 - 0xa0000000 : 1:1, uncached mapping */
590	.set	__base, 0
591	.rept	0xa00
592	.word	(__base << 20) | 0xc12
593	.set	__base, __base + 1
594	.endr
595
596	/* 0xa0000000 - 0xa0100000 : 1:1, cached mapping */
597	.word	(0xa00 << 20) | 0x1c1e
598
599	.set	__base, 0xa01
600	.rept	0x1000 - 0xa01
601	.word	(__base << 20) | 0xc12
602	.set	__base, __base + 1
603	.endr
604#endif	/* CONFIG_PRELOADER */
605