xref: /openbmc/u-boot/arch/arm/cpu/arm926ejs/start.S (revision 8343f8a76434b7162cf5a4da5f456b014868853c)
1/*
2 *  armboot - Startup Code for ARM926EJS CPU-core
3 *
4 *  Copyright (c) 2003  Texas Instruments
5 *
6 *  ----- Adapted for OMAP1610 OMAP730 from ARM925t code ------
7 *
8 *  Copyright (c) 2001	Marius Gr�ger <mag@sysgo.de>
9 *  Copyright (c) 2002	Alex Z�pke <azu@sysgo.de>
10 *  Copyright (c) 2002	Gary Jennejohn <garyj@denx.de>
11 *  Copyright (c) 2003	Richard Woodruff <r-woodruff2@ti.com>
12 *  Copyright (c) 2003	Kshitij <kshitij@ti.com>
13 *  Copyright (c) 2010	Albert Aribaud <albert.aribaud@free.fr>
14 *
15 * See file CREDITS for list of people who contributed to this
16 * project.
17 *
18 * This program is free software; you can redistribute it and/or
19 * modify it under the terms of the GNU General Public License as
20 * published by the Free Software Foundation; either version 2 of
21 * the License, or (at your option) any later version.
22 *
23 * This program is distributed in the hope that it will be useful,
24 * but WITHOUT ANY WARRANTY; without even the implied warranty of
25 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
26 * GNU General Public License for more details.
27 *
28 * You should have received a copy of the GNU General Public License
29 * along with this program; if not, write to the Free Software
30 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
31 * MA 02111-1307 USA
32 */
33
34#include <asm-offsets.h>
35#include <config.h>
36#include <common.h>
37#include <version.h>
38
39#if defined(CONFIG_OMAP1610)
40#include <./configs/omap1510.h>
41#elif defined(CONFIG_OMAP730)
42#include <./configs/omap730.h>
43#endif
44
45/*
46 *************************************************************************
47 *
48 * Jump vector table as in table 3.1 in [1]
49 *
50 *************************************************************************
51 */
52
53
54.globl _start
55_start:
56	b	reset
57#ifdef CONFIG_PRELOADER
58/* No exception handlers in preloader */
59	ldr	pc, _hang
60	ldr	pc, _hang
61	ldr	pc, _hang
62	ldr	pc, _hang
63	ldr	pc, _hang
64	ldr	pc, _hang
65	ldr	pc, _hang
66
67_hang:
68	.word	do_hang
69/* pad to 64 byte boundary */
70	.word	0x12345678
71	.word	0x12345678
72	.word	0x12345678
73	.word	0x12345678
74	.word	0x12345678
75	.word	0x12345678
76	.word	0x12345678
77#else
78	ldr	pc, _undefined_instruction
79	ldr	pc, _software_interrupt
80	ldr	pc, _prefetch_abort
81	ldr	pc, _data_abort
82	ldr	pc, _not_used
83	ldr	pc, _irq
84	ldr	pc, _fiq
85
86_undefined_instruction:
87	.word undefined_instruction
88_software_interrupt:
89	.word software_interrupt
90_prefetch_abort:
91	.word prefetch_abort
92_data_abort:
93	.word data_abort
94_not_used:
95	.word not_used
96_irq:
97	.word irq
98_fiq:
99	.word fiq
100
101#endif	/* CONFIG_PRELOADER */
102	.balignl 16,0xdeadbeef
103
104
105/*
106 *************************************************************************
107 *
108 * Startup Code (reset vector)
109 *
110 * do important init only if we don't start from memory!
111 * setup Memory and board specific bits prior to relocation.
112 * relocate armboot to ram
113 * setup stack
114 *
115 *************************************************************************
116 */
117
118.globl _TEXT_BASE
119_TEXT_BASE:
120	.word	CONFIG_SYS_TEXT_BASE
121
122/*
123 * These are defined in the board-specific linker script.
124 * Subtracting _start from them lets the linker put their
125 * relative position in the executable instead of leaving
126 * them null.
127 */
128.globl _bss_start_ofs
129_bss_start_ofs:
130	.word __bss_start - _start
131
132.globl _bss_end_ofs
133_bss_end_ofs:
134	.word _end - _start
135
136#ifdef CONFIG_USE_IRQ
137/* IRQ stack memory (calculated at run-time) */
138.globl IRQ_STACK_START
139IRQ_STACK_START:
140	.word	0x0badc0de
141
142/* IRQ stack memory (calculated at run-time) */
143.globl FIQ_STACK_START
144FIQ_STACK_START:
145	.word 0x0badc0de
146#endif
147
148#if !defined(CONFIG_SYS_ARM_WITHOUT_RELOC)
149/* IRQ stack memory (calculated at run-time) + 8 bytes */
150.globl IRQ_STACK_START_IN
151IRQ_STACK_START_IN:
152	.word	0x0badc0de
153
154/*
155 * the actual reset code
156 */
157
158reset:
159	/*
160	 * set the cpu to SVC32 mode
161	 */
162	mrs	r0,cpsr
163	bic	r0,r0,#0x1f
164	orr	r0,r0,#0xd3
165	msr	cpsr,r0
166
167	/*
168	 * we do sys-critical inits only at reboot,
169	 * not when booting from ram!
170	 */
171#ifndef CONFIG_SKIP_LOWLEVEL_INIT
172	bl	cpu_init_crit
173#endif
174
175/* Set stackpointer in internal RAM to call board_init_f */
176call_board_init_f:
177	ldr	sp, =(CONFIG_SYS_INIT_SP_ADDR)
178	ldr	r0,=0x00000000
179	bl	board_init_f
180
181/*------------------------------------------------------------------------------*/
182
183/*
184 * void relocate_code (addr_sp, gd, addr_moni)
185 *
186 * This "function" does not return, instead it continues in RAM
187 * after relocating the monitor code.
188 *
189 */
190	.globl	relocate_code
191relocate_code:
192	mov	r4, r0	/* save addr_sp */
193	mov	r5, r1	/* save addr of gd */
194	mov	r6, r2	/* save addr of destination */
195	mov	r7, r2	/* save addr of destination */
196
197	/* Set up the stack						    */
198stack_setup:
199	mov	sp, r4
200
201	adr	r0, _start
202	ldr	r2, _TEXT_BASE
203	ldr	r3, _bss_start_ofs
204	add	r2, r0, r3		/* r2 <- source end address	    */
205	cmp	r0, r6
206	beq	clear_bss
207
208#ifndef CONFIG_SKIP_RELOCATE_UBOOT
209copy_loop:
210	ldmia	r0!, {r9-r10}		/* copy from source address [r0]    */
211	stmia	r6!, {r9-r10}		/* copy to   target address [r1]    */
212	cmp	r0, r2			/* until source end address [r2]    */
213	blo	copy_loop
214
215#ifndef CONFIG_PRELOADER
216	/*
217	 * fix .rel.dyn relocations
218	 */
219	ldr	r0, _TEXT_BASE		/* r0 <- Text base */
220	sub	r9, r7, r0		/* r9 <- relocation offset */
221	ldr	r10, _dynsym_start_ofs	/* r10 <- sym table ofs */
222	add	r10, r10, r0		/* r10 <- sym table in FLASH */
223	ldr	r2, _rel_dyn_start_ofs	/* r2 <- rel dyn start ofs */
224	add	r2, r2, r0		/* r2 <- rel dyn start in FLASH */
225	ldr	r3, _rel_dyn_end_ofs	/* r3 <- rel dyn end ofs */
226	add	r3, r3, r0		/* r3 <- rel dyn end in FLASH */
227fixloop:
228	ldr	r0, [r2]		/* r0 <- location to fix up, IN FLASH! */
229	add	r0, r0, r9		/* r0 <- location to fix up in RAM */
230	ldr	r1, [r2, #4]
231	and	r8, r1, #0xff
232	cmp	r8, #23			/* relative fixup? */
233	beq	fixrel
234	cmp	r8, #2			/* absolute fixup? */
235	beq	fixabs
236	/* ignore unknown type of fixup */
237	b	fixnext
238fixabs:
239	/* absolute fix: set location to (offset) symbol value */
240	mov	r1, r1, LSR #4		/* r1 <- symbol index in .dynsym */
241	add	r1, r10, r1		/* r1 <- address of symbol in table */
242	ldr	r1, [r1, #4]		/* r1 <- symbol value */
243	add	r1, r9			/* r1 <- relocated sym addr */
244	b	fixnext
245fixrel:
246	/* relative fix: increase location by offset */
247	ldr	r1, [r0]
248	add	r1, r1, r9
249fixnext:
250	str	r1, [r0]
251	add	r2, r2, #8		/* each rel.dyn entry is 8 bytes */
252	cmp	r2, r3
253	blo	fixloop
254#endif
255#endif	/* #ifndef CONFIG_SKIP_RELOCATE_UBOOT */
256
257clear_bss:
258#ifndef CONFIG_PRELOADER
259	ldr	r0, _bss_start_ofs
260	ldr	r1, _bss_end_ofs
261	ldr	r3, _TEXT_BASE		/* Text base */
262	mov	r4, r7			/* reloc addr */
263	add	r0, r0, r4
264	add	r1, r1, r4
265	mov	r2, #0x00000000		/* clear			    */
266
267clbss_l:str	r2, [r0]		/* clear loop...		    */
268	add	r0, r0, #4
269	cmp	r0, r1
270	bne	clbss_l
271
272	bl coloured_LED_init
273	bl red_LED_on
274#endif
275
276/*
277 * We are done. Do not return, instead branch to second part of board
278 * initialization, now running from RAM.
279 */
280#ifdef CONFIG_NAND_SPL
281	ldr     r0, _nand_boot_ofs
282	mov	pc, r0
283
284_nand_boot_ofs:
285	.word nand_boot
286#else
287	ldr	r0, _board_init_r_ofs
288	adr	r1, _start
289	add	lr, r0, r1
290#ifndef CONFIG_SKIP_RELOCATE_UBOOT
291	add	lr, lr, r9
292#endif
293	/* setup parameters for board_init_r */
294	mov	r0, r5		/* gd_t */
295	mov	r1, r7		/* dest_addr */
296	/* jump to it ... */
297	mov	pc, lr
298
299_board_init_r_ofs:
300	.word board_init_r - _start
301#endif
302
303_rel_dyn_start_ofs:
304	.word __rel_dyn_start - _start
305_rel_dyn_end_ofs:
306	.word __rel_dyn_end - _start
307_dynsym_start_ofs:
308	.word __dynsym_start - _start
309
310#else /* #if !defined(CONFIG_SYS_ARM_WITHOUT_RELOC) */
311/*
312 * the actual reset code
313 */
314
315reset:
316	/*
317	 * set the cpu to SVC32 mode
318	 */
319	mrs	r0,cpsr
320	bic	r0,r0,#0x1f
321	orr	r0,r0,#0xd3
322	msr	cpsr,r0
323
324	/*
325	 * we do sys-critical inits only at reboot,
326	 * not when booting from ram!
327	 */
328#ifndef CONFIG_SKIP_LOWLEVEL_INIT
329	bl	cpu_init_crit
330#endif
331
332#ifndef CONFIG_SKIP_RELOCATE_UBOOT
333relocate:				/* relocate U-Boot to RAM	    */
334	adr	r0, _start		/* r0 <- current position of code   */
335	ldr	r1, _TEXT_BASE		/* test if we run from flash or RAM */
336	cmp     r0, r1                  /* don't reloc during debug         */
337	beq     stack_setup
338	ldr	r3, _bss_start_ofs	/* r3 <- _bss_start - _start	    */
339	add	r2, r0, r3		/* r2 <- source end address         */
340
341copy_loop:
342	ldmia	r0!, {r3-r10}		/* copy from source address [r0]    */
343	stmia	r1!, {r3-r10}		/* copy to   target address [r1]    */
344	cmp	r0, r2			/* until source end address [r2]    */
345	blo	copy_loop
346#endif	/* CONFIG_SKIP_RELOCATE_UBOOT */
347
348	/* Set up the stack						    */
349stack_setup:
350	ldr	r0, _TEXT_BASE		/* upper 128 KiB: relocated uboot   */
351	sub	sp, r0, #128		/* leave 32 words for abort-stack   */
352#ifndef CONFIG_PRELOADER
353	sub	r0, r0, #CONFIG_SYS_MALLOC_LEN	/* malloc area                      */
354	sub	r0, r0, #GENERATED_GBL_DATA_SIZE /* bdinfo                        */
355#ifdef CONFIG_USE_IRQ
356	sub	r0, r0, #(CONFIG_STACKSIZE_IRQ+CONFIG_STACKSIZE_FIQ)
357#endif
358#endif /* CONFIG_PRELOADER */
359	sub	sp, r0, #12		/* leave 3 words for abort-stack    */
360	bic	sp, sp, #7		/* 8-byte alignment for ABI compliance */
361
362clear_bss:
363	adr	r2, _start
364	ldr	r0, _bss_start_ofs	/* find start of bss segment        */
365	add	r0, r0, r2
366	ldr	r1, _bss_end_ofs	/* stop here                        */
367	add	r1, r1, r2
368	mov	r2, #0x00000000		/* clear                            */
369
370#ifndef CONFIG_PRELOADER
371clbss_l:str	r2, [r0]		/* clear loop...                    */
372	add	r0, r0, #4
373	cmp	r0, r1
374	blo	clbss_l
375
376	bl coloured_LED_init
377	bl red_LED_on
378#endif /* CONFIG_PRELOADER */
379
380	ldr	r0, _start_armboot_ofs
381	adr	r1, _start
382	add	r0, r0, r1
383	ldr	pc, r0
384
385_start_armboot_ofs:
386#ifdef CONFIG_NAND_SPL
387	.word nand_boot - _start
388#else
389	.word start_armboot - _start
390#endif /* CONFIG_NAND_SPL */
391#endif /* #if !defined(CONFIG_SYS_ARM_WITHOUT_RELOC) */
392
393/*
394 *************************************************************************
395 *
396 * CPU_init_critical registers
397 *
398 * setup important registers
399 * setup memory timing
400 *
401 *************************************************************************
402 */
403#ifndef CONFIG_SKIP_LOWLEVEL_INIT
404cpu_init_crit:
405	/*
406	 * flush v4 I/D caches
407	 */
408	mov	r0, #0
409	mcr	p15, 0, r0, c7, c7, 0	/* flush v3/v4 cache */
410	mcr	p15, 0, r0, c8, c7, 0	/* flush v4 TLB */
411
412	/*
413	 * disable MMU stuff and caches
414	 */
415	mrc	p15, 0, r0, c1, c0, 0
416	bic	r0, r0, #0x00002300	/* clear bits 13, 9:8 (--V- --RS) */
417	bic	r0, r0, #0x00000087	/* clear bits 7, 2:0 (B--- -CAM) */
418	orr	r0, r0, #0x00000002	/* set bit 2 (A) Align */
419	orr	r0, r0, #0x00001000	/* set bit 12 (I) I-Cache */
420	mcr	p15, 0, r0, c1, c0, 0
421
422	/*
423	 * Go setup Memory and board specific bits prior to relocation.
424	 */
425	mov	ip, lr		/* perserve link reg across call */
426	bl	lowlevel_init	/* go setup pll,mux,memory */
427	mov	lr, ip		/* restore link */
428	mov	pc, lr		/* back to my caller */
429#endif /* CONFIG_SKIP_LOWLEVEL_INIT */
430
431#ifndef CONFIG_PRELOADER
432/*
433 *************************************************************************
434 *
435 * Interrupt handling
436 *
437 *************************************************************************
438 */
439
440@
441@ IRQ stack frame.
442@
443#define S_FRAME_SIZE	72
444
445#define S_OLD_R0	68
446#define S_PSR		64
447#define S_PC		60
448#define S_LR		56
449#define S_SP		52
450
451#define S_IP		48
452#define S_FP		44
453#define S_R10		40
454#define S_R9		36
455#define S_R8		32
456#define S_R7		28
457#define S_R6		24
458#define S_R5		20
459#define S_R4		16
460#define S_R3		12
461#define S_R2		8
462#define S_R1		4
463#define S_R0		0
464
465#define MODE_SVC 0x13
466#define I_BIT	 0x80
467
468/*
469 * use bad_save_user_regs for abort/prefetch/undef/swi ...
470 * use irq_save_user_regs / irq_restore_user_regs for IRQ/FIQ handling
471 */
472
473	.macro	bad_save_user_regs
474	@ carve out a frame on current user stack
475	sub	sp, sp, #S_FRAME_SIZE
476	stmia	sp, {r0 - r12}	@ Save user registers (now in svc mode) r0-r12
477#if defined(CONFIG_SYS_ARM_WITHOUT_RELOC)
478	adr	r2, _start
479	sub	r2, r2, #(CONFIG_STACKSIZE+CONFIG_SYS_MALLOC_LEN)
480	sub	r2, r2, #(GENERATED_GBL_DATA_SIZE+8)  @ set base 2 words into abort stack
481#else
482	ldr	r2, IRQ_STACK_START_IN
483#endif
484	@ get values for "aborted" pc and cpsr (into parm regs)
485	ldmia	r2, {r2 - r3}
486	add	r0, sp, #S_FRAME_SIZE		@ grab pointer to old stack
487	add	r5, sp, #S_SP
488	mov	r1, lr
489	stmia	r5, {r0 - r3}	@ save sp_SVC, lr_SVC, pc, cpsr
490	mov	r0, sp		@ save current stack into r0 (param register)
491	.endm
492
493	.macro	irq_save_user_regs
494	sub	sp, sp, #S_FRAME_SIZE
495	stmia	sp, {r0 - r12}			@ Calling r0-r12
496	@ !!!! R8 NEEDS to be saved !!!! a reserved stack spot would be good.
497	add	r8, sp, #S_PC
498	stmdb	r8, {sp, lr}^		@ Calling SP, LR
499	str	lr, [r8, #0]		@ Save calling PC
500	mrs	r6, spsr
501	str	r6, [r8, #4]		@ Save CPSR
502	str	r0, [r8, #8]		@ Save OLD_R0
503	mov	r0, sp
504	.endm
505
506	.macro	irq_restore_user_regs
507	ldmia	sp, {r0 - lr}^			@ Calling r0 - lr
508	mov	r0, r0
509	ldr	lr, [sp, #S_PC]			@ Get PC
510	add	sp, sp, #S_FRAME_SIZE
511	subs	pc, lr, #4		@ return & move spsr_svc into cpsr
512	.endm
513
514	.macro get_bad_stack
515#if defined(CONFIG_SYS_ARM_WITHOUT_RELOC)
516	adr	r13, _start		@ setup our mode stack
517	sub	r13, r13, #(CONFIG_STACKSIZE+CONFIG_SYS_MALLOC_LEN)
518	sub	r13, r13, #(GENERATED_GBL_DATA_SIZE+8) @ reserved a couple spots in abort stack
519#else
520	ldr	r13, IRQ_STACK_START_IN		@ setup our mode stack
521#endif
522
523	str	lr, [r13]	@ save caller lr in position 0 of saved stack
524	mrs	lr, spsr	@ get the spsr
525	str	lr, [r13, #4]	@ save spsr in position 1 of saved stack
526	mov	r13, #MODE_SVC	@ prepare SVC-Mode
527	@ msr	spsr_c, r13
528	msr	spsr, r13	@ switch modes, make sure moves will execute
529	mov	lr, pc		@ capture return pc
530	movs	pc, lr		@ jump to next instruction & switch modes.
531	.endm
532
533	.macro get_irq_stack			@ setup IRQ stack
534	ldr	sp, IRQ_STACK_START
535	.endm
536
537	.macro get_fiq_stack			@ setup FIQ stack
538	ldr	sp, FIQ_STACK_START
539	.endm
540#endif	/* CONFIG_PRELOADER */
541
542/*
543 * exception handlers
544 */
545#ifdef CONFIG_PRELOADER
546	.align	5
547do_hang:
548	ldr	sp, _TEXT_BASE			/* switch to abort stack */
5491:
550	bl	1b				/* hang and never return */
551#else	/* !CONFIG_PRELOADER */
552	.align  5
553undefined_instruction:
554	get_bad_stack
555	bad_save_user_regs
556	bl	do_undefined_instruction
557
558	.align	5
559software_interrupt:
560	get_bad_stack
561	bad_save_user_regs
562	bl	do_software_interrupt
563
564	.align	5
565prefetch_abort:
566	get_bad_stack
567	bad_save_user_regs
568	bl	do_prefetch_abort
569
570	.align	5
571data_abort:
572	get_bad_stack
573	bad_save_user_regs
574	bl	do_data_abort
575
576	.align	5
577not_used:
578	get_bad_stack
579	bad_save_user_regs
580	bl	do_not_used
581
582#ifdef CONFIG_USE_IRQ
583
584	.align	5
585irq:
586	get_irq_stack
587	irq_save_user_regs
588	bl	do_irq
589	irq_restore_user_regs
590
591	.align	5
592fiq:
593	get_fiq_stack
594	/* someone ought to write a more effiction fiq_save_user_regs */
595	irq_save_user_regs
596	bl	do_fiq
597	irq_restore_user_regs
598
599#else
600
601	.align	5
602irq:
603	get_bad_stack
604	bad_save_user_regs
605	bl	do_irq
606
607	.align	5
608fiq:
609	get_bad_stack
610	bad_save_user_regs
611	bl	do_fiq
612
613#endif
614#endif	/* CONFIG_PRELOADER */
615