xref: /openbmc/u-boot/arch/arm/cpu/arm926ejs/start.S (revision a2ac1b3a)
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 Gröger <mag@sysgo.de>
9 *  Copyright (c) 2002	Alex Züpke <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.u.boot@aribaud.net>
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#ifdef CONFIG_SYS_DV_NOR_BOOT_CFG
55.globl _start
56_start:
57.globl _NOR_BOOT_CFG
58_NOR_BOOT_CFG:
59	.word	CONFIG_SYS_DV_NOR_BOOT_CFG
60	b	reset
61#else
62.globl _start
63_start:
64	b	reset
65#endif
66#ifdef CONFIG_SPL_BUILD
67/* No exception handlers in preloader */
68	ldr	pc, _hang
69	ldr	pc, _hang
70	ldr	pc, _hang
71	ldr	pc, _hang
72	ldr	pc, _hang
73	ldr	pc, _hang
74	ldr	pc, _hang
75
76_hang:
77	.word	do_hang
78/* pad to 64 byte boundary */
79	.word	0x12345678
80	.word	0x12345678
81	.word	0x12345678
82	.word	0x12345678
83	.word	0x12345678
84	.word	0x12345678
85	.word	0x12345678
86#else
87	ldr	pc, _undefined_instruction
88	ldr	pc, _software_interrupt
89	ldr	pc, _prefetch_abort
90	ldr	pc, _data_abort
91	ldr	pc, _not_used
92	ldr	pc, _irq
93	ldr	pc, _fiq
94
95_undefined_instruction:
96	.word undefined_instruction
97_software_interrupt:
98	.word software_interrupt
99_prefetch_abort:
100	.word prefetch_abort
101_data_abort:
102	.word data_abort
103_not_used:
104	.word not_used
105_irq:
106	.word irq
107_fiq:
108	.word fiq
109
110#endif	/* CONFIG_SPL_BUILD */
111	.balignl 16,0xdeadbeef
112
113
114/*
115 *************************************************************************
116 *
117 * Startup Code (reset vector)
118 *
119 * do important init only if we don't start from memory!
120 * setup Memory and board specific bits prior to relocation.
121 * relocate armboot to ram
122 * setup stack
123 *
124 *************************************************************************
125 */
126
127.globl _TEXT_BASE
128_TEXT_BASE:
129#ifdef CONFIG_NAND_SPL /* deprecated, use instead CONFIG_SPL_BUILD */
130	.word	CONFIG_SYS_TEXT_BASE
131#else
132#ifdef CONFIG_SPL_BUILD
133	.word	CONFIG_SPL_TEXT_BASE
134#else
135	.word	CONFIG_SYS_TEXT_BASE
136#endif
137#endif
138
139/*
140 * These are defined in the board-specific linker script.
141 * Subtracting _start from them lets the linker put their
142 * relative position in the executable instead of leaving
143 * them null.
144 */
145.globl _bss_start_ofs
146_bss_start_ofs:
147	.word __bss_start - _start
148
149.globl _bss_end_ofs
150_bss_end_ofs:
151	.word __bss_end__ - _start
152
153.globl _end_ofs
154_end_ofs:
155	.word _end - _start
156
157#ifdef CONFIG_NAND_U_BOOT
158.globl _end
159_end:
160	.word __bss_end__
161#endif
162
163#ifdef CONFIG_USE_IRQ
164/* IRQ stack memory (calculated at run-time) */
165.globl IRQ_STACK_START
166IRQ_STACK_START:
167	.word	0x0badc0de
168
169/* IRQ stack memory (calculated at run-time) */
170.globl FIQ_STACK_START
171FIQ_STACK_START:
172	.word 0x0badc0de
173#endif
174
175/* IRQ stack memory (calculated at run-time) + 8 bytes */
176.globl IRQ_STACK_START_IN
177IRQ_STACK_START_IN:
178	.word	0x0badc0de
179
180/*
181 * the actual reset code
182 */
183
184reset:
185	/*
186	 * set the cpu to SVC32 mode
187	 */
188	mrs	r0,cpsr
189	bic	r0,r0,#0x1f
190	orr	r0,r0,#0xd3
191	msr	cpsr,r0
192
193	/*
194	 * we do sys-critical inits only at reboot,
195	 * not when booting from ram!
196	 */
197#ifndef CONFIG_SKIP_LOWLEVEL_INIT
198	bl	cpu_init_crit
199#endif
200
201/* Set stackpointer in internal RAM to call board_init_f */
202call_board_init_f:
203#ifdef CONFIG_NAND_SPL /* deprecated, use instead CONFIG_SPL_BUILD */
204	ldr	sp, =(CONFIG_SYS_INIT_SP_ADDR)
205#else
206#ifdef CONFIG_SPL_BUILD
207	ldr	sp, =(CONFIG_SPL_STACK)
208#else
209	ldr	sp, =(CONFIG_SYS_INIT_SP_ADDR)
210#endif
211#endif
212	bic	sp, sp, #7 /* 8-byte alignment for ABI compliance */
213	ldr	r0,=0x00000000
214	bl	board_init_f
215
216/*------------------------------------------------------------------------------*/
217
218#if !defined(CONFIG_SPL_BUILD) || defined(CONFIG_NAND_SPL)
219/*
220 * void relocate_code (addr_sp, gd, addr_moni)
221 *
222 * This "function" does not return, instead it continues in RAM
223 * after relocating the monitor code.
224 *
225 */
226	.globl	relocate_code
227relocate_code:
228	mov	r4, r0	/* save addr_sp */
229	mov	r5, r1	/* save addr of gd */
230	mov	r6, r2	/* save addr of destination */
231
232	/* Set up the stack						    */
233stack_setup:
234	mov	sp, r4
235
236	adr	r0, _start
237	sub	r9, r6, r0		/* r9 <- relocation offset */
238	cmp	r0, r6
239	moveq	r9, #0		/* no relocation. relocation offset(r9) = 0 */
240	beq	clear_bss		/* skip relocation */
241	mov	r1, r6			/* r1 <- scratch for copy loop */
242	ldr	r3, _bss_start_ofs
243	add	r2, r0, r3		/* r2 <- source end address	    */
244
245copy_loop:
246	ldmia	r0!, {r9-r10}		/* copy from source address [r0]    */
247	stmia	r1!, {r9-r10}		/* copy to   target address [r1]    */
248	cmp	r0, r2			/* until source end address [r2]    */
249	blo	copy_loop
250
251#ifndef CONFIG_SPL_BUILD
252	/*
253	 * fix .rel.dyn relocations
254	 */
255	ldr	r0, _TEXT_BASE		/* r0 <- Text base */
256	sub	r9, r6, r0		/* r9 <- relocation offset */
257	ldr	r10, _dynsym_start_ofs	/* r10 <- sym table ofs */
258	add	r10, r10, r0		/* r10 <- sym table in FLASH */
259	ldr	r2, _rel_dyn_start_ofs	/* r2 <- rel dyn start ofs */
260	add	r2, r2, r0		/* r2 <- rel dyn start in FLASH */
261	ldr	r3, _rel_dyn_end_ofs	/* r3 <- rel dyn end ofs */
262	add	r3, r3, r0		/* r3 <- rel dyn end in FLASH */
263fixloop:
264	ldr	r0, [r2]		/* r0 <- location to fix up, IN FLASH! */
265	add	r0, r0, r9		/* r0 <- location to fix up in RAM */
266	ldr	r1, [r2, #4]
267	and	r7, r1, #0xff
268	cmp	r7, #23			/* relative fixup? */
269	beq	fixrel
270	cmp	r7, #2			/* absolute fixup? */
271	beq	fixabs
272	/* ignore unknown type of fixup */
273	b	fixnext
274fixabs:
275	/* absolute fix: set location to (offset) symbol value */
276	mov	r1, r1, LSR #4		/* r1 <- symbol index in .dynsym */
277	add	r1, r10, r1		/* r1 <- address of symbol in table */
278	ldr	r1, [r1, #4]		/* r1 <- symbol value */
279	add	r1, r1, r9		/* r1 <- relocated sym addr */
280	b	fixnext
281fixrel:
282	/* relative fix: increase location by offset */
283	ldr	r1, [r0]
284	add	r1, r1, r9
285fixnext:
286	str	r1, [r0]
287	add	r2, r2, #8		/* each rel.dyn entry is 8 bytes */
288	cmp	r2, r3
289	blo	fixloop
290#endif
291
292clear_bss:
293#ifdef CONFIG_SPL_BUILD
294	/* No relocation for SPL */
295	ldr	r0, =__bss_start
296	ldr	r1, =__bss_end__
297#else
298	ldr	r0, _bss_start_ofs
299	ldr	r1, _bss_end_ofs
300	mov	r4, r6			/* reloc addr */
301	add	r0, r0, r4
302	add	r1, r1, r4
303#endif
304	mov	r2, #0x00000000		/* clear			    */
305
306clbss_l:cmp	r0, r1			/* clear loop... */
307	bhs	clbss_e			/* if reached end of bss, exit */
308	str	r2, [r0]
309	add	r0, r0, #4
310	b	clbss_l
311clbss_e:
312
313#ifndef CONFIG_SPL_BUILD
314	bl coloured_LED_init
315	bl red_led_on
316#endif
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_NAND_SPL
323	ldr     r0, _nand_boot_ofs
324	mov	pc, r0
325
326_nand_boot_ofs:
327	.word nand_boot
328#else
329	ldr	r0, _board_init_r_ofs
330	ldr	r1, _TEXT_BASE
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, r6		/* dest_addr */
336	/* jump to it ... */
337	mov	pc, lr
338
339_board_init_r_ofs:
340	.word board_init_r - _start
341#endif
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#endif
350
351/*
352 *************************************************************************
353 *
354 * CPU_init_critical registers
355 *
356 * setup important registers
357 * setup memory timing
358 *
359 *************************************************************************
360 */
361#ifndef CONFIG_SKIP_LOWLEVEL_INIT
362cpu_init_crit:
363	/*
364	 * flush D cache before disabling it
365	 */
366	mov	r0, #0
367flush_dcache:
368	mrc	p15, 0, r15, c7, c10, 3
369	bne	flush_dcache
370
371	mcr	p15, 0, r0, c8, c7, 0	/* invalidate TLB */
372	mcr	p15, 0, r0, c7, c5, 0	/* invalidate I Cache */
373
374	/*
375	 * disable MMU and D cache
376	 * enable I cache if CONFIG_SYS_ICACHE_OFF is not defined
377	 */
378	mrc	p15, 0, r0, c1, c0, 0
379	bic	r0, r0, #0x00000300	/* clear bits 9:8 (---- --RS) */
380	bic	r0, r0, #0x00000087	/* clear bits 7, 2:0 (B--- -CAM) */
381#ifdef CONFIG_SYS_EXCEPTION_VECTORS_HIGH
382	orr	r0, r0, #0x00002000	/* set bit 13 (--V- ----) */
383#else
384	bic	r0, r0, #0x00002000	/* clear bit 13 (--V- ----) */
385#endif
386	orr	r0, r0, #0x00000002	/* set bit 2 (A) Align */
387#ifndef CONFIG_SYS_ICACHE_OFF
388	orr	r0, r0, #0x00001000	/* set bit 12 (I) I-Cache */
389#endif
390	mcr	p15, 0, r0, c1, c0, 0
391
392	/*
393	 * Go setup Memory and board specific bits prior to relocation.
394	 */
395	mov	ip, lr		/* perserve link reg across call */
396	bl	lowlevel_init	/* go setup pll,mux,memory */
397	mov	lr, ip		/* restore link */
398	mov	pc, lr		/* back to my caller */
399#endif /* CONFIG_SKIP_LOWLEVEL_INIT */
400
401#ifndef CONFIG_SPL_BUILD
402/*
403 *************************************************************************
404 *
405 * Interrupt handling
406 *
407 *************************************************************************
408 */
409
410@
411@ IRQ stack frame.
412@
413#define S_FRAME_SIZE	72
414
415#define S_OLD_R0	68
416#define S_PSR		64
417#define S_PC		60
418#define S_LR		56
419#define S_SP		52
420
421#define S_IP		48
422#define S_FP		44
423#define S_R10		40
424#define S_R9		36
425#define S_R8		32
426#define S_R7		28
427#define S_R6		24
428#define S_R5		20
429#define S_R4		16
430#define S_R3		12
431#define S_R2		8
432#define S_R1		4
433#define S_R0		0
434
435#define MODE_SVC 0x13
436#define I_BIT	 0x80
437
438/*
439 * use bad_save_user_regs for abort/prefetch/undef/swi ...
440 * use irq_save_user_regs / irq_restore_user_regs for IRQ/FIQ handling
441 */
442
443	.macro	bad_save_user_regs
444	@ carve out a frame on current user stack
445	sub	sp, sp, #S_FRAME_SIZE
446	stmia	sp, {r0 - r12}	@ Save user registers (now in svc mode) r0-r12
447	ldr	r2, IRQ_STACK_START_IN
448	@ get values for "aborted" pc and cpsr (into parm regs)
449	ldmia	r2, {r2 - r3}
450	add	r0, sp, #S_FRAME_SIZE		@ grab pointer to old stack
451	add	r5, sp, #S_SP
452	mov	r1, lr
453	stmia	r5, {r0 - r3}	@ save sp_SVC, lr_SVC, pc, cpsr
454	mov	r0, sp		@ save current stack into r0 (param register)
455	.endm
456
457	.macro	irq_save_user_regs
458	sub	sp, sp, #S_FRAME_SIZE
459	stmia	sp, {r0 - r12}			@ Calling r0-r12
460	@ !!!! R8 NEEDS to be saved !!!! a reserved stack spot would be good.
461	add	r8, sp, #S_PC
462	stmdb	r8, {sp, lr}^		@ Calling SP, LR
463	str	lr, [r8, #0]		@ Save calling PC
464	mrs	r6, spsr
465	str	r6, [r8, #4]		@ Save CPSR
466	str	r0, [r8, #8]		@ Save OLD_R0
467	mov	r0, sp
468	.endm
469
470	.macro	irq_restore_user_regs
471	ldmia	sp, {r0 - lr}^			@ Calling r0 - lr
472	mov	r0, r0
473	ldr	lr, [sp, #S_PC]			@ Get PC
474	add	sp, sp, #S_FRAME_SIZE
475	subs	pc, lr, #4		@ return & move spsr_svc into cpsr
476	.endm
477
478	.macro get_bad_stack
479	ldr	r13, IRQ_STACK_START_IN		@ setup our mode stack
480
481	str	lr, [r13]	@ save caller lr in position 0 of saved stack
482	mrs	lr, spsr	@ get the spsr
483	str	lr, [r13, #4]	@ save spsr in position 1 of saved stack
484	mov	r13, #MODE_SVC	@ prepare SVC-Mode
485	@ msr	spsr_c, r13
486	msr	spsr, r13	@ switch modes, make sure moves will execute
487	mov	lr, pc		@ capture return pc
488	movs	pc, lr		@ jump to next instruction & switch modes.
489	.endm
490
491	.macro get_irq_stack			@ setup IRQ stack
492	ldr	sp, IRQ_STACK_START
493	.endm
494
495	.macro get_fiq_stack			@ setup FIQ stack
496	ldr	sp, FIQ_STACK_START
497	.endm
498#endif	/* CONFIG_SPL_BUILD */
499
500/*
501 * exception handlers
502 */
503#ifdef CONFIG_SPL_BUILD
504	.align	5
505do_hang:
506	ldr	sp, _TEXT_BASE			/* switch to abort stack */
5071:
508	bl	1b				/* hang and never return */
509#else	/* !CONFIG_SPL_BUILD */
510	.align  5
511undefined_instruction:
512	get_bad_stack
513	bad_save_user_regs
514	bl	do_undefined_instruction
515
516	.align	5
517software_interrupt:
518	get_bad_stack
519	bad_save_user_regs
520	bl	do_software_interrupt
521
522	.align	5
523prefetch_abort:
524	get_bad_stack
525	bad_save_user_regs
526	bl	do_prefetch_abort
527
528	.align	5
529data_abort:
530	get_bad_stack
531	bad_save_user_regs
532	bl	do_data_abort
533
534	.align	5
535not_used:
536	get_bad_stack
537	bad_save_user_regs
538	bl	do_not_used
539
540#ifdef CONFIG_USE_IRQ
541
542	.align	5
543irq:
544	get_irq_stack
545	irq_save_user_regs
546	bl	do_irq
547	irq_restore_user_regs
548
549	.align	5
550fiq:
551	get_fiq_stack
552	/* someone ought to write a more effiction fiq_save_user_regs */
553	irq_save_user_regs
554	bl	do_fiq
555	irq_restore_user_regs
556
557#else
558
559	.align	5
560irq:
561	get_bad_stack
562	bad_save_user_regs
563	bl	do_irq
564
565	.align	5
566fiq:
567	get_bad_stack
568	bad_save_user_regs
569	bl	do_fiq
570
571#endif
572#endif	/* CONFIG_SPL_BUILD */
573