xref: /openbmc/u-boot/arch/arm/cpu/pxa/start.S (revision ae03661f)
1/*
2 *  armboot - Startup Code for XScale CPU-core
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) 2001	Marius Groger <mag@sysgo.de>
9 *  Copyright (C) 2002	Alex Zupke <azu@sysgo.de>
10 *  Copyright (C) 2002	Gary Jennejohn <garyj@denx.de>
11 *  Copyright (C) 2002	Kyle Harris <kharris@nexus-tech.net>
12 *  Copyright (C) 2003	Kai-Uwe Bloem <kai-uwe.bloem@auerswald.de>
13 *  Copyright (C) 2003	Kshitij <kshitij@ti.com>
14 *  Copyright (C) 2003	Richard Woodruff <r-woodruff2@ti.com>
15 *  Copyright (C) 2003	Robert Schwebel <r.schwebel@pengutronix.de>
16 *  Copyright (C) 2004	Texas Instruments <r-woodruff2@ti.com>
17 *  Copyright (C) 2010	Marek Vasut <marek.vasut@gmail.com>
18 *
19 * See file CREDITS for list of people who contributed to this
20 * project.
21 *
22 * This program is free software; you can redistribute it and/or
23 * modify it under the terms of the GNU General Public License as
24 * published by the Free Software Foundation; either version 2 of
25 * the License, or (at your option) any later version.
26 *
27 * This program is distributed in the hope that it will be useful,
28 * but WITHOUT ANY WARRANTY; without even the implied warranty of
29 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the
30 * GNU General Public License for more details.
31 *
32 * You should have received a copy of the GNU General Public License
33 * along with this program; if not, write to the Free Software
34 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
35 * MA 02111-1307 USA
36 */
37
38#include <asm-offsets.h>
39#include <config.h>
40#include <version.h>
41
42#ifdef CONFIG_CPU_PXA25X
43#if ((CONFIG_SYS_INIT_SP_ADDR) != 0xfffff800)
44#error "Init SP address must be set to 0xfffff800 for PXA250"
45#endif
46#endif
47
48.globl _start
49_start: b	reset
50#ifdef CONFIG_SPL_BUILD
51	ldr	pc, _hang
52	ldr	pc, _hang
53	ldr	pc, _hang
54	ldr	pc, _hang
55	ldr	pc, _hang
56	ldr	pc, _hang
57	ldr	pc, _hang
58
59_hang:
60	.word	do_hang
61	.word	0x12345678
62	.word	0x12345678
63	.word	0x12345678
64	.word	0x12345678
65	.word	0x12345678
66	.word	0x12345678
67	.word	0x12345678	/* now 16*4=64 */
68#else
69	ldr	pc, _undefined_instruction
70	ldr	pc, _software_interrupt
71	ldr	pc, _prefetch_abort
72	ldr	pc, _data_abort
73	ldr	pc, _not_used
74	ldr	pc, _irq
75	ldr	pc, _fiq
76
77_undefined_instruction: .word undefined_instruction
78_software_interrupt:	.word software_interrupt
79_prefetch_abort:	.word prefetch_abort
80_data_abort:		.word data_abort
81_not_used:		.word not_used
82_irq:			.word irq
83_fiq:			.word fiq
84_pad:			.word 0x12345678 /* now 16*4=64 */
85#endif	/* CONFIG_SPL_BUILD */
86.global _end_vect
87_end_vect:
88
89	.balignl 16,0xdeadbeef
90/*
91 *************************************************************************
92 *
93 * Startup Code (reset vector)
94 *
95 * do important init only if we don't start from memory!
96 * setup Memory and board specific bits prior to relocation.
97 * relocate armboot to ram
98 * setup stack
99 *
100 *************************************************************************
101 */
102
103.globl _TEXT_BASE
104_TEXT_BASE:
105#ifdef	CONFIG_SPL_BUILD
106	.word	CONFIG_SPL_TEXT_BASE
107#else
108	.word	CONFIG_SYS_TEXT_BASE
109#endif
110
111/*
112 * These are defined in the board-specific linker script.
113 * Subtracting _start from them lets the linker put their
114 * relative position in the executable instead of leaving
115 * them null.
116 */
117.globl _bss_start_ofs
118_bss_start_ofs:
119	.word __bss_start - _start
120
121.globl _bss_end_ofs
122_bss_end_ofs:
123	.word __bss_end__ - _start
124
125.globl _end_ofs
126_end_ofs:
127	.word _end - _start
128
129#ifdef CONFIG_USE_IRQ
130/* IRQ stack memory (calculated at run-time) */
131.globl IRQ_STACK_START
132IRQ_STACK_START:
133	.word	0x0badc0de
134
135/* IRQ stack memory (calculated at run-time) */
136.globl FIQ_STACK_START
137FIQ_STACK_START:
138	.word 0x0badc0de
139#endif
140
141/* IRQ stack memory (calculated at run-time) + 8 bytes */
142.globl IRQ_STACK_START_IN
143IRQ_STACK_START_IN:
144	.word	0x0badc0de
145
146/*
147 * the actual reset code
148 */
149
150reset:
151	/*
152	 * set the cpu to SVC32 mode
153	 */
154	mrs	r0,cpsr
155	bic	r0,r0,#0x1f
156	orr	r0,r0,#0xd3
157	msr	cpsr,r0
158
159#ifndef CONFIG_SKIP_LOWLEVEL_INIT
160	bl  cpu_init_crit
161#endif
162
163#ifdef	CONFIG_CPU_PXA25X
164	bl	lock_cache_for_stack
165#endif
166
167/* Set stackpointer in internal RAM to call board_init_f */
168call_board_init_f:
169	ldr	sp, =(CONFIG_SYS_INIT_SP_ADDR)
170	bic	sp, sp, #7 /* 8-byte alignment for ABI compliance */
171	ldr	r0, =0x00000000
172	bl	board_init_f
173
174/*------------------------------------------------------------------------------*/
175#ifndef CONFIG_SPL_BUILD
176/*
177 * void relocate_code (addr_sp, gd, addr_moni)
178 *
179 * This "function" does not return, instead it continues in RAM
180 * after relocating the monitor code.
181 *
182 */
183	.globl	relocate_code
184relocate_code:
185	mov	r4, r0	/* save addr_sp */
186	mov	r5, r1	/* save addr of gd */
187	mov	r6, r2	/* save addr of destination */
188
189	/* Set up the stack						    */
190stack_setup:
191	mov	sp, r4
192
193/* Disable the Dcache RAM lock for stack now */
194#ifdef	CONFIG_CPU_PXA25X
195	bl	cpu_init_crit
196#endif
197
198	adr	r0, _start
199	cmp	r0, r6
200	beq	clear_bss		/* skip relocation */
201	mov	r1, r6			/* r1 <- scratch for copy_loop */
202	ldr	r3, _bss_start_ofs
203	add	r2, r0, r3		/* r2 <- source end address	    */
204
205copy_loop:
206	ldmia	r0!, {r9-r10}		/* copy from source address [r0]    */
207	stmia	r1!, {r9-r10}		/* copy to   target address [r1]    */
208	cmp	r0, r2			/* until source end address [r2]    */
209	blo	copy_loop
210
211#ifndef CONFIG_SPL_BUILD
212	/*
213	 * fix .rel.dyn relocations
214	 */
215	ldr	r0, _TEXT_BASE		/* r0 <- Text base */
216	sub	r9, r6, r0		/* r9 <- relocation offset */
217	ldr	r10, _dynsym_start_ofs	/* r10 <- sym table ofs */
218	add	r10, r10, r0		/* r10 <- sym table in FLASH */
219	ldr	r2, _rel_dyn_start_ofs	/* r2 <- rel dyn start ofs */
220	add	r2, r2, r0		/* r2 <- rel dyn start in FLASH */
221	ldr	r3, _rel_dyn_end_ofs	/* r3 <- rel dyn end ofs */
222	add	r3, r3, r0		/* r3 <- rel dyn end in FLASH */
223fixloop:
224	ldr	r0, [r2]		/* r0 <- location to fix up, IN FLASH! */
225	add	r0, r0, r9		/* r0 <- location to fix up in RAM */
226	ldr	r1, [r2, #4]
227	and	r7, r1, #0xff
228	cmp	r7, #23			/* relative fixup? */
229	beq	fixrel
230	cmp	r7, #2			/* absolute fixup? */
231	beq	fixabs
232	/* ignore unknown type of fixup */
233	b	fixnext
234fixabs:
235	/* absolute fix: set location to (offset) symbol value */
236	mov	r1, r1, LSR #4		/* r1 <- symbol index in .dynsym */
237	add	r1, r10, r1		/* r1 <- address of symbol in table */
238	ldr	r1, [r1, #4]		/* r1 <- symbol value */
239	add	r1, r1, r9		/* r1 <- relocated sym addr */
240	b	fixnext
241fixrel:
242	/* relative fix: increase location by offset */
243	ldr	r1, [r0]
244	add	r1, r1, r9
245fixnext:
246	str	r1, [r0]
247	add	r2, r2, #8		/* each rel.dyn entry is 8 bytes */
248	cmp	r2, r3
249	blo	fixloop
250#endif
251
252clear_bss:
253#ifndef CONFIG_SPL_BUILD
254	ldr	r0, _bss_start_ofs
255	ldr	r1, _bss_end_ofs
256	mov	r4, r6			/* reloc addr */
257	add	r0, r0, r4
258	add	r1, r1, r4
259	mov	r2, #0x00000000		/* clear			    */
260
261clbss_l:str	r2, [r0]		/* clear loop...		    */
262	add	r0, r0, #4
263	cmp	r0, r1
264	bne	clbss_l
265#endif	/* #ifndef CONFIG_SPL_BUILD */
266
267/*
268 * We are done. Do not return, instead branch to second part of board
269 * initialization, now running from RAM.
270 */
271#ifdef CONFIG_ONENAND_SPL
272	ldr     r0, _onenand_boot_ofs
273	mov	pc, r0
274
275_onenand_boot_ofs:
276	.word onenand_boot
277#else
278jump_2_ram:
279	ldr	r0, _board_init_r_ofs
280	ldr     r1, _TEXT_BASE
281	add	lr, r0, r1
282	add	lr, lr, r9
283	/* setup parameters for board_init_r */
284	mov	r0, r5		/* gd_t */
285	mov	r1, r6		/* dest_addr */
286	/* jump to it ... */
287	mov	pc, lr
288
289_board_init_r_ofs:
290	.word board_init_r - _start
291#endif
292
293_rel_dyn_start_ofs:
294	.word __rel_dyn_start - _start
295_rel_dyn_end_ofs:
296	.word __rel_dyn_end - _start
297_dynsym_start_ofs:
298	.word __dynsym_start - _start
299#endif
300/*
301 *************************************************************************
302 *
303 * CPU_init_critical registers
304 *
305 * setup important registers
306 * setup memory timing
307 *
308 *************************************************************************
309 */
310#if !defined(CONFIG_SKIP_LOWLEVEL_INIT) || defined(CONFIG_CPU_PXA25X)
311cpu_init_crit:
312	/*
313	 * flush v4 I/D caches
314	 */
315	mov	r0, #0
316	mcr	p15, 0, r0, c7, c7, 0	/* Invalidate I+D+BTB caches */
317	mcr	p15, 0, r0, c8, c7, 0	/* Invalidate Unified TLB */
318
319	/*
320	 * disable MMU stuff and caches
321	 */
322	mrc	p15, 0, r0, c1, c0, 0
323	bic	r0, r0, #0x00002300	@ clear bits 13, 9:8 (--V- --RS)
324	bic	r0, r0, #0x00000087	@ clear bits 7, 2:0 (B--- -CAM)
325	orr	r0, r0, #0x00000002	@ set bit 2 (A) Align
326	orr	r0, r0, #0x00001000	@ set bit 12 (I) I-Cache
327	mcr	p15, 0, r0, c1, c0, 0
328
329	mov	pc, lr		/* back to my caller */
330#endif /* !CONFIG_SKIP_LOWLEVEL_INIT || CONFIG_CPU_PXA25X */
331
332#ifndef CONFIG_SPL_BUILD
333/*
334 *************************************************************************
335 *
336 * Interrupt handling
337 *
338 *************************************************************************
339 */
340@
341@ IRQ stack frame.
342@
343#define S_FRAME_SIZE	72
344
345#define S_OLD_R0	68
346#define S_PSR		64
347#define S_PC		60
348#define S_LR		56
349#define S_SP		52
350
351#define S_IP		48
352#define S_FP		44
353#define S_R10		40
354#define S_R9		36
355#define S_R8		32
356#define S_R7		28
357#define S_R6		24
358#define S_R5		20
359#define S_R4		16
360#define S_R3		12
361#define S_R2		8
362#define S_R1		4
363#define S_R0		0
364
365#define MODE_SVC 0x13
366#define I_BIT	 0x80
367
368/*
369 * use bad_save_user_regs for abort/prefetch/undef/swi ...
370 * use irq_save_user_regs / irq_restore_user_regs for IRQ/FIQ handling
371 */
372
373	.macro	bad_save_user_regs
374	sub	sp, sp, #S_FRAME_SIZE		@ carve out a frame on current user stack
375	stmia	sp, {r0 - r12}			@ Save user registers (now in svc mode) r0-r12
376
377	ldr	r2, IRQ_STACK_START_IN		@ set base 2 words into abort stack
378	ldmia	r2, {r2 - r3}			@ get values for "aborted" pc and cpsr (into parm regs)
379	add	r0, sp, #S_FRAME_SIZE		@ grab pointer to old stack
380
381	add	r5, sp, #S_SP
382	mov	r1, lr
383	stmia	r5, {r0 - r3}			@ save sp_SVC, lr_SVC, pc, cpsr
384	mov	r0, sp				@ save current stack into r0 (param register)
385	.endm
386
387	.macro	irq_save_user_regs
388	sub	sp, sp, #S_FRAME_SIZE
389	stmia	sp, {r0 - r12}			@ Calling r0-r12
390	add	r8, sp, #S_PC			@ !!!! R8 NEEDS to be saved !!!! a reserved stack spot would be good.
391	stmdb	r8, {sp, lr}^			@ Calling SP, LR
392	str	lr, [r8, #0]			@ Save calling PC
393	mrs	r6, spsr
394	str	r6, [r8, #4]			@ Save CPSR
395	str	r0, [r8, #8]			@ Save OLD_R0
396	mov	r0, sp
397	.endm
398
399	.macro	irq_restore_user_regs
400	ldmia	sp, {r0 - lr}^			@ Calling r0 - lr
401	mov	r0, r0
402	ldr	lr, [sp, #S_PC]			@ Get PC
403	add	sp, sp, #S_FRAME_SIZE
404	subs	pc, lr, #4			@ return & move spsr_svc into cpsr
405	.endm
406
407	.macro get_bad_stack
408	ldr	r13, IRQ_STACK_START_IN		@ setup our mode stack (enter in banked mode)
409
410	str	lr, [r13]			@ save caller lr in position 0 of saved stack
411	mrs	lr, spsr			@ get the spsr
412	str	lr, [r13, #4]			@ save spsr in position 1 of saved stack
413
414	mov	r13, #MODE_SVC			@ prepare SVC-Mode
415	@ msr	spsr_c, r13
416	msr	spsr, r13			@ switch modes, make sure moves will execute
417	mov	lr, pc				@ capture return pc
418	movs	pc, lr				@ jump to next instruction & switch modes.
419	.endm
420
421	.macro get_bad_stack_swi
422	sub	r13, r13, #4			@ space on current stack for scratch reg.
423	str	r0, [r13]			@ save R0's value.
424	ldr	r0, IRQ_STACK_START_IN		@ get data regions start
425	str	lr, [r0]			@ save caller lr in position 0 of saved stack
426	mrs	r0, spsr			@ get the spsr
427	str	lr, [r0, #4]			@ save spsr in position 1 of saved stack
428	ldr	r0, [r13]			@ restore r0
429	add	r13, r13, #4			@ pop stack entry
430	.endm
431
432	.macro get_irq_stack			@ setup IRQ stack
433	ldr	sp, IRQ_STACK_START
434	.endm
435
436	.macro get_fiq_stack			@ setup FIQ stack
437	ldr	sp, FIQ_STACK_START
438	.endm
439#endif	/* CONFIG_SPL_BUILD */
440
441/*
442 * exception handlers
443 */
444#ifdef CONFIG_SPL_BUILD
445	.align	5
446do_hang:
447	ldr	sp, _TEXT_BASE			/* use 32 words about stack */
448	bl	hang				/* hang and never return */
449#else	/* !CONFIG_SPL_BUILD */
450	.align	5
451undefined_instruction:
452	get_bad_stack
453	bad_save_user_regs
454	bl	do_undefined_instruction
455
456	.align	5
457software_interrupt:
458	get_bad_stack_swi
459	bad_save_user_regs
460	bl	do_software_interrupt
461
462	.align	5
463prefetch_abort:
464	get_bad_stack
465	bad_save_user_regs
466	bl	do_prefetch_abort
467
468	.align	5
469data_abort:
470	get_bad_stack
471	bad_save_user_regs
472	bl	do_data_abort
473
474	.align	5
475not_used:
476	get_bad_stack
477	bad_save_user_regs
478	bl	do_not_used
479
480#ifdef CONFIG_USE_IRQ
481
482	.align	5
483irq:
484	get_irq_stack
485	irq_save_user_regs
486	bl	do_irq
487	irq_restore_user_regs
488
489	.align	5
490fiq:
491	get_fiq_stack
492	/* someone ought to write a more effiction fiq_save_user_regs */
493	irq_save_user_regs
494	bl	do_fiq
495	irq_restore_user_regs
496
497#else
498
499	.align	5
500irq:
501	get_bad_stack
502	bad_save_user_regs
503	bl	do_irq
504
505	.align	5
506fiq:
507	get_bad_stack
508	bad_save_user_regs
509	bl	do_fiq
510
511#endif
512	.align 5
513#endif	/* CONFIG_SPL_BUILD */
514
515
516/*
517 * Enable MMU to use DCache as DRAM.
518 *
519 * This is useful on PXA25x and PXA26x in early bootstages, where there is no
520 * other possible memory available to hold stack.
521 */
522#ifdef CONFIG_CPU_PXA25X
523.macro CPWAIT reg
524	mrc	p15, 0, \reg, c2, c0, 0
525	mov	\reg, \reg
526	sub	pc, pc, #4
527.endm
528lock_cache_for_stack:
529	/* Domain access -- enable for all CPs */
530	ldr	r0, =0x0000ffff
531	mcr	p15, 0, r0, c3, c0, 0
532
533	/* Point TTBR to MMU table */
534	ldr	r0, =mmutable
535	mcr	p15, 0, r0, c2, c0, 0
536
537	/* Kick in MMU, ICache, DCache, BTB */
538	mrc	p15, 0, r0, c1, c0, 0
539	bic	r0, #0x1b00
540	bic	r0, #0x0087
541	orr	r0, #0x1800
542	orr	r0, #0x0005
543	mcr	p15, 0, r0, c1, c0, 0
544	CPWAIT	r0
545
546	/* Unlock Icache, Dcache */
547	mcr	p15, 0, r0, c9, c1, 1
548	mcr	p15, 0, r0, c9, c2, 1
549
550	/* Flush Icache, Dcache, BTB */
551	mcr	p15, 0, r0, c7, c7, 0
552
553	/* Unlock I-TLB, D-TLB */
554	mcr	p15, 0, r0, c10, c4, 1
555	mcr	p15, 0, r0, c10, c8, 1
556
557	/* Flush TLB */
558	mcr	p15, 0, r0, c8, c7, 0
559
560	/* Allocate 4096 bytes of Dcache as RAM */
561
562	/* Drain pending loads and stores */
563	mcr	p15, 0, r0, c7, c10, 4
564
565	mov	r4, #0x00
566	mov	r5, #0x00
567	mov	r2, #0x01
568	mcr	p15, 0, r0, c9, c2, 0
569	CPWAIT	r0
570
571	/* 128 lines reserved (128 x 32bytes = 4096 bytes total) */
572	mov	r0, #128
573	ldr	r1, =0xfffff000
574
575alloc:
576	mcr	p15, 0, r1, c7, c2, 5
577	/* Drain pending loads and stores */
578	mcr	p15, 0, r0, c7, c10, 4
579	strd	r4, [r1], #8
580	strd	r4, [r1], #8
581	strd	r4, [r1], #8
582	strd	r4, [r1], #8
583	subs	r0, #0x01
584	bne	alloc
585	/* Drain pending loads and stores */
586	mcr	p15, 0, r0, c7, c10, 4
587	mov	r2, #0x00
588	mcr	p15, 0, r2, c9, c2, 0
589	CPWAIT	r0
590
591	mov	pc, lr
592
593.section .mmutable, "a"
594mmutable:
595	.align	14
596	/* 0x00000000 - 0xffe00000 : 1:1, uncached mapping */
597	.set	__base, 0
598	.rept	0xfff
599	.word	(__base << 20) | 0xc12
600	.set	__base, __base + 1
601	.endr
602
603	/* 0xfff00000 : 1:1, cached mapping */
604	.word	(0xfff << 20) | 0x1c1e
605#endif	/* CONFIG_CPU_PXA25X */
606