xref: /openbmc/u-boot/arch/arm/cpu/arm926ejs/start.S (revision c91d456c)
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 *
14 * See file CREDITS for list of people who contributed to this
15 * project.
16 *
17 * This program is free software; you can redistribute it and/or
18 * modify it under the terms of the GNU General Public License as
19 * published by the Free Software Foundation; either version 2 of
20 * the License, or (at your option) any later version.
21 *
22 * This program is distributed in the hope that it will be useful,
23 * but WITHOUT ANY WARRANTY; without even the implied warranty of
24 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
25 * GNU General Public License for more details.
26 *
27 * You should have received a copy of the GNU General Public License
28 * along with this program; if not, write to the Free Software
29 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
30 * MA 02111-1307 USA
31 */
32
33
34#include <config.h>
35#include <common.h>
36#include <version.h>
37
38#if defined(CONFIG_OMAP1610)
39#include <./configs/omap1510.h>
40#elif defined(CONFIG_OMAP730)
41#include <./configs/omap730.h>
42#endif
43
44/*
45 *************************************************************************
46 *
47 * Jump vector table as in table 3.1 in [1]
48 *
49 *************************************************************************
50 */
51
52
53.globl _start
54_start:
55	b	reset
56#ifdef CONFIG_PRELOADER
57/* No exception handlers in preloader */
58	ldr	pc, _hang
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
66_hang:
67	.word	do_hang
68/* pad to 64 byte boundary */
69	.word	0x12345678
70	.word	0x12345678
71	.word	0x12345678
72	.word	0x12345678
73	.word	0x12345678
74	.word	0x12345678
75	.word	0x12345678
76#else
77	ldr	pc, _undefined_instruction
78	ldr	pc, _software_interrupt
79	ldr	pc, _prefetch_abort
80	ldr	pc, _data_abort
81	ldr	pc, _not_used
82	ldr	pc, _irq
83	ldr	pc, _fiq
84
85_undefined_instruction:
86	.word undefined_instruction
87_software_interrupt:
88	.word software_interrupt
89_prefetch_abort:
90	.word prefetch_abort
91_data_abort:
92	.word data_abort
93_not_used:
94	.word not_used
95_irq:
96	.word irq
97_fiq:
98	.word fiq
99
100#endif	/* CONFIG_PRELOADER */
101	.balignl 16,0xdeadbeef
102
103
104/*
105 *************************************************************************
106 *
107 * Startup Code (reset vector)
108 *
109 * do important init only if we don't start from memory!
110 * setup Memory and board specific bits prior to relocation.
111 * relocate armboot to ram
112 * setup stack
113 *
114 *************************************************************************
115 */
116
117.globl _TEXT_BASE
118_TEXT_BASE:
119	.word	TEXT_BASE
120
121#if defined(CONFIG_SYS_ARM_WITHOUT_RELOC)
122.globl _armboot_start
123_armboot_start:
124	.word _start
125#endif
126
127/*
128 * These are defined in the board-specific linker script.
129 */
130.globl _bss_start
131_bss_start:
132	.word __bss_start
133
134.globl _bss_end
135_bss_end:
136	.word _end
137
138#ifdef CONFIG_USE_IRQ
139/* IRQ stack memory (calculated at run-time) */
140.globl IRQ_STACK_START
141IRQ_STACK_START:
142	.word	0x0badc0de
143
144/* IRQ stack memory (calculated at run-time) */
145.globl FIQ_STACK_START
146FIQ_STACK_START:
147	.word 0x0badc0de
148#endif
149
150#if !defined(CONFIG_SYS_ARM_WITHOUT_RELOC)
151/* IRQ stack memory (calculated at run-time) + 8 bytes */
152.globl IRQ_STACK_START_IN
153IRQ_STACK_START_IN:
154	.word	0x0badc0de
155
156.globl _datarel_start
157_datarel_start:
158	.word __datarel_start
159
160.globl _datarelrolocal_start
161_datarelrolocal_start:
162	.word __datarelrolocal_start
163
164.globl _datarellocal_start
165_datarellocal_start:
166	.word __datarellocal_start
167
168.globl _datarelro_start
169_datarelro_start:
170	.word __datarelro_start
171
172.globl _got_start
173_got_start:
174	.word __got_start
175
176.globl _got_end
177_got_end:
178	.word __got_end
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	ldr	sp, =(CONFIG_SYS_INIT_SP_ADDR)
204	ldr	r0,=0x00000000
205	bl	board_init_f
206
207/*------------------------------------------------------------------------------*/
208
209/*
210 * void relocate_code (addr_sp, gd, addr_moni)
211 *
212 * This "function" does not return, instead it continues in RAM
213 * after relocating the monitor code.
214 *
215 */
216	.globl	relocate_code
217relocate_code:
218	mov	r4, r0	/* save addr_sp */
219	mov	r5, r1	/* save addr of gd */
220	mov	r6, r2	/* save addr of destination */
221	mov	r7, r2	/* save addr of destination */
222
223	/* Set up the stack						    */
224stack_setup:
225	mov	sp, r4
226
227	adr	r0, _start
228	ldr	r2, _TEXT_BASE
229	ldr	r3, _bss_start
230	sub	r2, r3, r2		/* r2 <- size of armboot	    */
231	add	r2, r0, r2		/* r2 <- source end address	    */
232	cmp	r0, r6
233	beq	clear_bss
234
235#ifndef CONFIG_SKIP_RELOCATE_UBOOT
236copy_loop:
237	ldmia	r0!, {r9-r10}		/* copy from source address [r0]    */
238	stmia	r6!, {r9-r10}		/* copy to   target address [r1]    */
239	cmp	r0, r2			/* until source end addreee [r2]    */
240	ble	copy_loop
241
242#ifndef CONFIG_PRELOADER
243	/* fix got entries */
244	ldr	r1, _TEXT_BASE		/* Text base */
245	mov	r0, r7			/* reloc addr */
246	ldr	r2, _got_start		/* addr in Flash */
247	ldr	r3, _got_end		/* addr in Flash */
248	sub	r3, r3, r1
249	add	r3, r3, r0
250	sub	r2, r2, r1
251	add	r2, r2, r0
252
253fixloop:
254	ldr	r4, [r2]
255	sub	r4, r4, r1
256	add	r4, r4, r0
257	str	r4, [r2]
258	add	r2, r2, #4
259	cmp	r2, r3
260	bne	fixloop
261#endif
262#endif	/* #ifndef CONFIG_SKIP_RELOCATE_UBOOT */
263
264clear_bss:
265#ifndef CONFIG_PRELOADER
266	ldr	r0, _bss_start
267	ldr	r1, _bss_end
268	ldr	r3, _TEXT_BASE		/* Text base */
269	mov	r4, r7			/* reloc addr */
270	sub	r0, r0, r3
271	add	r0, r0, r4
272	sub	r1, r1, r3
273	add	r1, r1, r4
274	mov	r2, #0x00000000		/* clear			    */
275
276clbss_l:str	r2, [r0]		/* clear loop...		    */
277	add	r0, r0, #4
278	cmp	r0, r1
279	bne	clbss_l
280
281	bl coloured_LED_init
282	bl red_LED_on
283#endif
284
285/*
286 * We are done. Do not return, instead branch to second part of board
287 * initialization, now running from RAM.
288 */
289#ifdef CONFIG_NAND_SPL
290	ldr     pc, _nand_boot
291
292_nand_boot: .word nand_boot
293#else
294	ldr	r0, _TEXT_BASE
295	ldr	r2, _board_init_r
296	sub	r2, r2, r0
297	add	r2, r2, r7	/* position from board_init_r in RAM */
298	/* setup parameters for board_init_r */
299	mov	r0, r5		/* gd_t */
300	mov	r1, r7		/* dest_addr */
301	/* jump to it ... */
302	mov	lr, r2
303	mov	pc, lr
304
305_board_init_r: .word board_init_r
306#endif
307
308#else /* #if !defined(CONFIG_SYS_ARM_WITHOUT_RELOC) */
309/*
310 * the actual reset code
311 */
312
313reset:
314	/*
315	 * set the cpu to SVC32 mode
316	 */
317	mrs	r0,cpsr
318	bic	r0,r0,#0x1f
319	orr	r0,r0,#0xd3
320	msr	cpsr,r0
321
322	/*
323	 * we do sys-critical inits only at reboot,
324	 * not when booting from ram!
325	 */
326#ifndef CONFIG_SKIP_LOWLEVEL_INIT
327	bl	cpu_init_crit
328#endif
329
330#ifndef CONFIG_SKIP_RELOCATE_UBOOT
331relocate:				/* relocate U-Boot to RAM	    */
332	adr	r0, _start		/* r0 <- current position of code   */
333	ldr	r1, _TEXT_BASE		/* test if we run from flash or RAM */
334	cmp     r0, r1                  /* don't reloc during debug         */
335	beq     stack_setup
336	ldr	r2, _armboot_start
337	ldr	r3, _bss_start
338	sub	r2, r3, r2		/* r2 <- size of armboot            */
339	add	r2, r0, r2		/* 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 addreee [r2]    */
345	ble	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, #CONFIG_SYS_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	ldr	r0, _bss_start		/* find start of bss segment        */
364	ldr	r1, _bss_end		/* stop here                        */
365	mov	r2, #0x00000000		/* clear                            */
366
367#ifndef CONFIG_PRELOADER
368clbss_l:str	r2, [r0]		/* clear loop...                    */
369	add	r0, r0, #4
370	cmp	r0, r1
371	ble	clbss_l
372
373	bl coloured_LED_init
374	bl red_LED_on
375#endif /* CONFIG_PRELOADER */
376
377	ldr	pc, _start_armboot
378
379_start_armboot:
380#ifdef CONFIG_NAND_SPL
381	.word nand_boot
382#else
383	.word start_armboot
384#endif /* CONFIG_NAND_SPL */
385#endif /* #if !defined(CONFIG_SYS_ARM_WITHOUT_RELOC) */
386
387/*
388 *************************************************************************
389 *
390 * CPU_init_critical registers
391 *
392 * setup important registers
393 * setup memory timing
394 *
395 *************************************************************************
396 */
397#ifndef CONFIG_SKIP_LOWLEVEL_INIT
398cpu_init_crit:
399	/*
400	 * flush v4 I/D caches
401	 */
402	mov	r0, #0
403	mcr	p15, 0, r0, c7, c7, 0	/* flush v3/v4 cache */
404	mcr	p15, 0, r0, c8, c7, 0	/* flush v4 TLB */
405
406	/*
407	 * disable MMU stuff and caches
408	 */
409	mrc	p15, 0, r0, c1, c0, 0
410	bic	r0, r0, #0x00002300	/* clear bits 13, 9:8 (--V- --RS) */
411	bic	r0, r0, #0x00000087	/* clear bits 7, 2:0 (B--- -CAM) */
412	orr	r0, r0, #0x00000002	/* set bit 2 (A) Align */
413	orr	r0, r0, #0x00001000	/* set bit 12 (I) I-Cache */
414	mcr	p15, 0, r0, c1, c0, 0
415
416	/*
417	 * Go setup Memory and board specific bits prior to relocation.
418	 */
419	mov	ip, lr		/* perserve link reg across call */
420	bl	lowlevel_init	/* go setup pll,mux,memory */
421	mov	lr, ip		/* restore link */
422	mov	pc, lr		/* back to my caller */
423#endif /* CONFIG_SKIP_LOWLEVEL_INIT */
424
425#ifndef CONFIG_PRELOADER
426/*
427 *************************************************************************
428 *
429 * Interrupt handling
430 *
431 *************************************************************************
432 */
433
434@
435@ IRQ stack frame.
436@
437#define S_FRAME_SIZE	72
438
439#define S_OLD_R0	68
440#define S_PSR		64
441#define S_PC		60
442#define S_LR		56
443#define S_SP		52
444
445#define S_IP		48
446#define S_FP		44
447#define S_R10		40
448#define S_R9		36
449#define S_R8		32
450#define S_R7		28
451#define S_R6		24
452#define S_R5		20
453#define S_R4		16
454#define S_R3		12
455#define S_R2		8
456#define S_R1		4
457#define S_R0		0
458
459#define MODE_SVC 0x13
460#define I_BIT	 0x80
461
462/*
463 * use bad_save_user_regs for abort/prefetch/undef/swi ...
464 * use irq_save_user_regs / irq_restore_user_regs for IRQ/FIQ handling
465 */
466
467	.macro	bad_save_user_regs
468	@ carve out a frame on current user stack
469	sub	sp, sp, #S_FRAME_SIZE
470	stmia	sp, {r0 - r12}	@ Save user registers (now in svc mode) r0-r12
471#if defined(CONFIG_SYS_ARM_WITHOUT_RELOC)
472	ldr	r2, _armboot_start
473	sub	r2, r2, #(CONFIG_STACKSIZE+CONFIG_SYS_MALLOC_LEN)
474	sub	r2, r2, #(CONFIG_SYS_GBL_DATA_SIZE+8)  @ set base 2 words into abort stack
475#else
476	ldr	r2, IRQ_STACK_START_IN
477#endif
478	@ get values for "aborted" pc and cpsr (into parm regs)
479	ldmia	r2, {r2 - r3}
480	add	r0, sp, #S_FRAME_SIZE		@ grab pointer to old stack
481	add	r5, sp, #S_SP
482	mov	r1, lr
483	stmia	r5, {r0 - r3}	@ save sp_SVC, lr_SVC, pc, cpsr
484	mov	r0, sp		@ save current stack into r0 (param register)
485	.endm
486
487	.macro	irq_save_user_regs
488	sub	sp, sp, #S_FRAME_SIZE
489	stmia	sp, {r0 - r12}			@ Calling r0-r12
490	@ !!!! R8 NEEDS to be saved !!!! a reserved stack spot would be good.
491	add	r8, sp, #S_PC
492	stmdb	r8, {sp, lr}^		@ Calling SP, LR
493	str	lr, [r8, #0]		@ Save calling PC
494	mrs	r6, spsr
495	str	r6, [r8, #4]		@ Save CPSR
496	str	r0, [r8, #8]		@ Save OLD_R0
497	mov	r0, sp
498	.endm
499
500	.macro	irq_restore_user_regs
501	ldmia	sp, {r0 - lr}^			@ Calling r0 - lr
502	mov	r0, r0
503	ldr	lr, [sp, #S_PC]			@ Get PC
504	add	sp, sp, #S_FRAME_SIZE
505	subs	pc, lr, #4		@ return & move spsr_svc into cpsr
506	.endm
507
508	.macro get_bad_stack
509#if defined(CONFIG_SYS_ARM_WITHOUT_RELOC)
510	ldr	r13, _armboot_start		@ setup our mode stack
511	sub	r13, r13, #(CONFIG_STACKSIZE+CONFIG_SYS_MALLOC_LEN)
512	sub	r13, r13, #(CONFIG_SYS_GBL_DATA_SIZE+8) @ reserved a couple spots in abort stack
513#else
514	ldr	r13, IRQ_STACK_START_IN		@ setup our mode stack
515#endif
516
517	str	lr, [r13]	@ save caller lr in position 0 of saved stack
518	mrs	lr, spsr	@ get the spsr
519	str	lr, [r13, #4]	@ save spsr in position 1 of saved stack
520	mov	r13, #MODE_SVC	@ prepare SVC-Mode
521	@ msr	spsr_c, r13
522	msr	spsr, r13	@ switch modes, make sure moves will execute
523	mov	lr, pc		@ capture return pc
524	movs	pc, lr		@ jump to next instruction & switch modes.
525	.endm
526
527	.macro get_irq_stack			@ setup IRQ stack
528	ldr	sp, IRQ_STACK_START
529	.endm
530
531	.macro get_fiq_stack			@ setup FIQ stack
532	ldr	sp, FIQ_STACK_START
533	.endm
534#endif	/* CONFIG_PRELOADER */
535
536/*
537 * exception handlers
538 */
539#ifdef CONFIG_PRELOADER
540	.align	5
541do_hang:
542	ldr	sp, _TEXT_BASE			/* switch to abort stack */
5431:
544	bl	1b				/* hang and never return */
545#else	/* !CONFIG_PRELOADER */
546	.align  5
547undefined_instruction:
548	get_bad_stack
549	bad_save_user_regs
550	bl	do_undefined_instruction
551
552	.align	5
553software_interrupt:
554	get_bad_stack
555	bad_save_user_regs
556	bl	do_software_interrupt
557
558	.align	5
559prefetch_abort:
560	get_bad_stack
561	bad_save_user_regs
562	bl	do_prefetch_abort
563
564	.align	5
565data_abort:
566	get_bad_stack
567	bad_save_user_regs
568	bl	do_data_abort
569
570	.align	5
571not_used:
572	get_bad_stack
573	bad_save_user_regs
574	bl	do_not_used
575
576#ifdef CONFIG_USE_IRQ
577
578	.align	5
579irq:
580	get_irq_stack
581	irq_save_user_regs
582	bl	do_irq
583	irq_restore_user_regs
584
585	.align	5
586fiq:
587	get_fiq_stack
588	/* someone ought to write a more effiction fiq_save_user_regs */
589	irq_save_user_regs
590	bl	do_fiq
591	irq_restore_user_regs
592
593#else
594
595	.align	5
596irq:
597	get_bad_stack
598	bad_save_user_regs
599	bl	do_irq
600
601	.align	5
602fiq:
603	get_bad_stack
604	bad_save_user_regs
605	bl	do_fiq
606
607#endif
608#endif	/* CONFIG_PRELOADER */
609