xref: /openbmc/u-boot/arch/arm/cpu/armv7/start.S (revision 071bc923)
1/*
2 * armboot - Startup Code for OMAP3530/ARM Cortex CPU-core
3 *
4 * Copyright (c) 2004	Texas Instruments <r-woodruff2@ti.com>
5 *
6 * Copyright (c) 2001	Marius Gröger <mag@sysgo.de>
7 * Copyright (c) 2002	Alex Züpke <azu@sysgo.de>
8 * Copyright (c) 2002	Gary Jennejohn <garyj@denx.de>
9 * Copyright (c) 2003	Richard Woodruff <r-woodruff2@ti.com>
10 * Copyright (c) 2003	Kshitij <kshitij@ti.com>
11 * Copyright (c) 2006-2008 Syed Mohammed Khasim <x0khasim@ti.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
36.globl _start
37_start: b	reset
38	ldr	pc, _undefined_instruction
39	ldr	pc, _software_interrupt
40	ldr	pc, _prefetch_abort
41	ldr	pc, _data_abort
42	ldr	pc, _not_used
43	ldr	pc, _irq
44	ldr	pc, _fiq
45
46_undefined_instruction: .word undefined_instruction
47_software_interrupt:	.word software_interrupt
48_prefetch_abort:	.word prefetch_abort
49_data_abort:		.word data_abort
50_not_used:		.word not_used
51_irq:			.word irq
52_fiq:			.word fiq
53_pad:			.word 0x12345678 /* now 16*4=64 */
54.global _end_vect
55_end_vect:
56
57	.balignl 16,0xdeadbeef
58/*************************************************************************
59 *
60 * Startup Code (reset vector)
61 *
62 * do important init only if we don't start from memory!
63 * setup Memory and board specific bits prior to relocation.
64 * relocate armboot to ram
65 * setup stack
66 *
67 *************************************************************************/
68
69.globl _TEXT_BASE
70_TEXT_BASE:
71	.word	CONFIG_SYS_TEXT_BASE
72
73#if defined(CONFIG_SYS_ARM_WITHOUT_RELOC)
74.globl _armboot_start
75_armboot_start:
76	.word _start
77#endif
78
79/*
80 * These are defined in the board-specific linker script.
81 */
82.globl _bss_start_ofs
83_bss_start_ofs:
84	.word __bss_start - _start
85
86.globl _bss_end_ofs
87_bss_end_ofs:
88	.word _end - _start
89
90#ifdef CONFIG_USE_IRQ
91/* IRQ stack memory (calculated at run-time) */
92.globl IRQ_STACK_START
93IRQ_STACK_START:
94	.word	0x0badc0de
95
96/* IRQ stack memory (calculated at run-time) */
97.globl FIQ_STACK_START
98FIQ_STACK_START:
99	.word 0x0badc0de
100#endif
101
102#if !defined(CONFIG_SYS_ARM_WITHOUT_RELOC)
103/* IRQ stack memory (calculated at run-time) + 8 bytes */
104.globl IRQ_STACK_START_IN
105IRQ_STACK_START_IN:
106	.word	0x0badc0de
107
108.globl _datarel_start_ofs
109_datarel_start_ofs:
110	.word __datarel_start - _start
111
112.globl _datarelrolocal_start_ofs
113_datarelrolocal_start_ofs:
114	.word __datarelrolocal_start - _start
115
116.globl _datarellocal_start_ofs
117_datarellocal_start_ofs:
118	.word __datarellocal_start - _start
119
120.globl _datarelro_start_ofs
121_datarelro_start_ofs:
122	.word __datarelro_start - _start
123
124.globl _got_start_ofs
125_got_start_ofs:
126	.word __got_start - _start
127
128.globl _got_end_Ofs
129_got_end_ofs:
130	.word __got_end - _start
131
132/*
133 * the actual reset code
134 */
135
136reset:
137	/*
138	 * set the cpu to SVC32 mode
139	 */
140	mrs	r0, cpsr
141	bic	r0, r0, #0x1f
142	orr	r0, r0, #0xd3
143	msr	cpsr,r0
144
145#if (CONFIG_OMAP34XX)
146	/* Copy vectors to mask ROM indirect addr */
147	adr	r0, _start		@ r0 <- current position of code
148	add	r0, r0, #4		@ skip reset vector
149	mov	r2, #64			@ r2 <- size to copy
150	add	r2, r0, r2		@ r2 <- source end address
151	mov	r1, #SRAM_OFFSET0	@ build vect addr
152	mov	r3, #SRAM_OFFSET1
153	add	r1, r1, r3
154	mov	r3, #SRAM_OFFSET2
155	add	r1, r1, r3
156next:
157	ldmia	r0!, {r3 - r10}		@ copy from source address [r0]
158	stmia	r1!, {r3 - r10}		@ copy to   target address [r1]
159	cmp	r0, r2			@ until source end address [r2]
160	bne	next			@ loop until equal */
161#if !defined(CONFIG_SYS_NAND_BOOT) && !defined(CONFIG_SYS_ONENAND_BOOT)
162	/* No need to copy/exec the clock code - DPLL adjust already done
163	 * in NAND/oneNAND Boot.
164	 */
165	bl	cpy_clk_code		@ put dpll adjust code behind vectors
166#endif /* NAND Boot */
167#endif
168	/* the mask ROM code should have PLL and others stable */
169#ifndef CONFIG_SKIP_LOWLEVEL_INIT
170	bl	cpu_init_crit
171#endif
172
173/* Set stackpointer in internal RAM to call board_init_f */
174call_board_init_f:
175	ldr	sp, =(CONFIG_SYS_INIT_SP_ADDR)
176	ldr	r0,=0x00000000
177	bl	board_init_f
178
179/*------------------------------------------------------------------------------*/
180
181/*
182 * void relocate_code (addr_sp, gd, addr_moni)
183 *
184 * This "function" does not return, instead it continues in RAM
185 * after relocating the monitor code.
186 *
187 */
188	.globl	relocate_code
189relocate_code:
190	mov	r4, r0	/* save addr_sp */
191	mov	r5, r1	/* save addr of gd */
192	mov	r6, r2	/* save addr of destination */
193	mov	r7, r2	/* save addr of destination */
194
195	/* Set up the stack						    */
196stack_setup:
197	mov	sp, r4
198
199#ifndef CONFIG_SKIP_RELOCATE_UBOOT
200	adr	r0, _start
201	ldr	r2, _TEXT_BASE
202	ldr	r3, _bss_start_ofs
203	add	r2, r0, r3		/* r2 <- source end address	    */
204	cmp	r0, r6
205#ifndef CONFIG_PRELOADER
206	beq	jump_2_ram
207#endif
208
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
255clear_bss:
256	ldr	r0, _bss_start_ofs
257	ldr	r1, _bss_end_ofs
258	ldr	r3, _TEXT_BASE		/* Text base */
259	mov	r4, r7			/* reloc addr */
260	add	r0, r0, r4
261	add	r1, r1, r4
262	mov	r2, #0x00000000		/* clear			    */
263
264clbss_l:str	r2, [r0]		/* clear loop...		    */
265	add	r0, r0, #4
266	cmp	r0, r1
267	bne	clbss_l
268#endif	/* #ifndef CONFIG_PRELOADER */
269#endif	/* #ifndef CONFIG_SKIP_RELOCATE_UBOOT */
270
271/*
272 * We are done. Do not return, instead branch to second part of board
273 * initialization, now running from RAM.
274 */
275jump_2_ram:
276	ldr	r0, _board_init_r_ofs
277	adr	r1, _start
278	add	lr, r0, r1
279#ifndef CONFIG_SKIP_RELOCATE_UBOOT
280	add	lr, lr, r9
281#endif
282	/* setup parameters for board_init_r */
283	mov	r0, r5		/* gd_t */
284	mov	r1, r7		/* dest_addr */
285	/* jump to it ... */
286	mov	pc, lr
287
288_board_init_r_ofs:
289	.word board_init_r - _start
290
291_rel_dyn_start_ofs:
292	.word __rel_dyn_start - _start
293_rel_dyn_end_ofs:
294	.word __rel_dyn_end - _start
295_dynsym_start_ofs:
296	.word __dynsym_start - _start
297
298#else /* #if !defined(CONFIG_SYS_ARM_WITHOUT_RELOC) */
299/*
300 * the actual reset code
301 */
302
303reset:
304	/*
305	 * set the cpu to SVC32 mode
306	 */
307	mrs	r0, cpsr
308	bic	r0, r0, #0x1f
309	orr	r0, r0, #0xd3
310	msr	cpsr,r0
311
312#if (CONFIG_OMAP34XX)
313	/* Copy vectors to mask ROM indirect addr */
314	adr	r0, _start		@ r0 <- current position of code
315	add	r0, r0, #4		@ skip reset vector
316	mov	r2, #64			@ r2 <- size to copy
317	add	r2, r0, r2		@ r2 <- source end address
318	mov	r1, #SRAM_OFFSET0	@ build vect addr
319	mov	r3, #SRAM_OFFSET1
320	add	r1, r1, r3
321	mov	r3, #SRAM_OFFSET2
322	add	r1, r1, r3
323next:
324	ldmia	r0!, {r3 - r10}		@ copy from source address [r0]
325	stmia	r1!, {r3 - r10}		@ copy to   target address [r1]
326	cmp	r0, r2			@ until source end address [r2]
327	bne	next			@ loop until equal */
328#if !defined(CONFIG_SYS_NAND_BOOT) && !defined(CONFIG_SYS_ONENAND_BOOT)
329	/* No need to copy/exec the clock code - DPLL adjust already done
330	 * in NAND/oneNAND Boot.
331	 */
332	bl	cpy_clk_code		@ put dpll adjust code behind vectors
333#endif /* NAND Boot */
334#endif
335	/* the mask ROM code should have PLL and others stable */
336#ifndef CONFIG_SKIP_LOWLEVEL_INIT
337	bl	cpu_init_crit
338#endif
339
340#ifndef CONFIG_SKIP_RELOCATE_UBOOT
341relocate:				@ relocate U-Boot to RAM
342	adr	r0, _start		@ r0 <- current position of code
343	ldr	r1, _TEXT_BASE		@ test if we run from flash or RAM
344	cmp	r0, r1			@ don't reloc during debug
345	beq	stack_setup
346
347	ldr	r2, _armboot_start
348	ldr	r3, _bss_start
349	sub	r2, r3, r2		@ r2 <- size of armboot
350	add	r2, r0, r2		@ r2 <- source end address
351
352copy_loop:				@ copy 32 bytes at a time
353	ldmia	r0!, {r3 - r10}		@ copy from source address [r0]
354	stmia	r1!, {r3 - r10}		@ copy to   target address [r1]
355	cmp	r0, r2			@ until source end address [r2]
356	blo	copy_loop
357#endif	/* CONFIG_SKIP_RELOCATE_UBOOT */
358
359	/* Set up the stack */
360stack_setup:
361	ldr	r0, _TEXT_BASE		@ upper 128 KiB: relocated uboot
362	sub	r0, r0, #CONFIG_SYS_MALLOC_LEN @ malloc area
363	sub	r0, r0, #GENERATED_GBL_DATA_SIZE @ bdinfo
364#ifdef CONFIG_USE_IRQ
365	sub	r0, r0, #(CONFIG_STACKSIZE_IRQ + CONFIG_STACKSIZE_FIQ)
366#endif
367	sub	sp, r0, #12		@ leave 3 words for abort-stack
368	bic	sp, sp, #7		@ 8-byte alignment for ABI compliance
369
370	/* Clear BSS (if any). Is below tx (watch load addr - need space) */
371clear_bss:
372	ldr	r0, _bss_start		@ find start of bss segment
373	ldr	r1, _bss_end		@ stop here
374	mov	r2, #0x00000000		@ clear value
375clbss_l:
376	str	r2, [r0]		@ clear BSS location
377	cmp	r0, r1			@ are we at the end yet
378	add	r0, r0, #4		@ increment clear index pointer
379	bne	clbss_l			@ keep clearing till at end
380
381	ldr	pc, _start_armboot	@ jump to C code
382
383_start_armboot: .word start_armboot
384#endif /* #if !defined(CONFIG_SYS_ARM_WITHOUT_RELOC) */
385
386/*************************************************************************
387 *
388 * CPU_init_critical registers
389 *
390 * setup important registers
391 * setup memory timing
392 *
393 *************************************************************************/
394cpu_init_crit:
395	/*
396	 * Invalidate L1 I/D
397	 */
398	mov	r0, #0			@ set up for MCR
399	mcr	p15, 0, r0, c8, c7, 0	@ invalidate TLBs
400	mcr	p15, 0, r0, c7, c5, 0	@ invalidate icache
401
402	/*
403	 * disable MMU stuff and caches
404	 */
405	mrc	p15, 0, r0, c1, c0, 0
406	bic	r0, r0, #0x00002000	@ clear bits 13 (--V-)
407	bic	r0, r0, #0x00000007	@ clear bits 2:0 (-CAM)
408	orr	r0, r0, #0x00000002	@ set bit 1 (--A-) Align
409	orr	r0, r0, #0x00000800	@ set bit 12 (Z---) BTB
410	mcr	p15, 0, r0, c1, c0, 0
411
412	/*
413	 * Jump to board specific initialization...
414	 * The Mask ROM will have already initialized
415	 * basic memory. Go here to bump up clock rate and handle
416	 * wake up conditions.
417	 */
418	mov	ip, lr			@ persevere link reg across call
419	bl	lowlevel_init		@ go setup pll,mux,memory
420	mov	lr, ip			@ restore link
421	mov	pc, lr			@ back to my caller
422/*
423 *************************************************************************
424 *
425 * Interrupt handling
426 *
427 *************************************************************************
428 */
429@
430@ IRQ stack frame.
431@
432#define S_FRAME_SIZE	72
433
434#define S_OLD_R0	68
435#define S_PSR		64
436#define S_PC		60
437#define S_LR		56
438#define S_SP		52
439
440#define S_IP		48
441#define S_FP		44
442#define S_R10		40
443#define S_R9		36
444#define S_R8		32
445#define S_R7		28
446#define S_R6		24
447#define S_R5		20
448#define S_R4		16
449#define S_R3		12
450#define S_R2		8
451#define S_R1		4
452#define S_R0		0
453
454#define MODE_SVC 0x13
455#define I_BIT	 0x80
456
457/*
458 * use bad_save_user_regs for abort/prefetch/undef/swi ...
459 * use irq_save_user_regs / irq_restore_user_regs for IRQ/FIQ handling
460 */
461
462	.macro	bad_save_user_regs
463	sub	sp, sp, #S_FRAME_SIZE		@ carve out a frame on current
464						@ user stack
465	stmia	sp, {r0 - r12}			@ Save user registers (now in
466						@ svc mode) r0-r12
467#if defined(CONFIG_SYS_ARM_WITHOUT_RELOC)
468	ldr	r2, _armboot_start
469	sub	r2, r2, #(CONFIG_SYS_MALLOC_LEN)
470	sub	r2, r2, #(GENERATED_GBL_DATA_SIZE + 8)	@ set base 2 words into abort
471#else
472	ldr	r2, IRQ_STACK_START_IN		@ set base 2 words into abort
473						@ stack
474#endif
475	ldmia	r2, {r2 - r3}			@ get values for "aborted" pc
476						@ and cpsr (into parm regs)
477	add	r0, sp, #S_FRAME_SIZE		@ grab pointer to old stack
478
479	add	r5, sp, #S_SP
480	mov	r1, lr
481	stmia	r5, {r0 - r3}			@ save sp_SVC, lr_SVC, pc, cpsr
482	mov	r0, sp				@ save current stack into r0
483						@ (param register)
484	.endm
485
486	.macro	irq_save_user_regs
487	sub	sp, sp, #S_FRAME_SIZE
488	stmia	sp, {r0 - r12}			@ Calling r0-r12
489	add	r8, sp, #S_PC			@ !! R8 NEEDS to be saved !!
490						@ a reserved stack spot would
491						@ be good.
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
506						@ cpsr
507	.endm
508
509	.macro get_bad_stack
510#if defined(CONFIG_SYS_ARM_WITHOUT_RELOC)
511	ldr	r13, _armboot_start		@ setup our mode stack (enter
512	sub	r13, r13, #(CONFIG_SYS_MALLOC_LEN)	@ move past malloc pool
513	sub	r13, r13, #(GENERATED_GBL_DATA_SIZE + 8) @ move to reserved a couple
514#else
515	ldr	r13, IRQ_STACK_START_IN		@ setup our mode stack (enter
516						@ in banked mode)
517#endif
518
519	str	lr, [r13]			@ save caller lr in position 0
520						@ of saved stack
521	mrs	lr, spsr			@ get the spsr
522	str	lr, [r13, #4]			@ save spsr in position 1 of
523						@ saved stack
524
525	mov	r13, #MODE_SVC			@ prepare SVC-Mode
526	@ msr	spsr_c, r13
527	msr	spsr, r13			@ switch modes, make sure
528						@ moves will execute
529	mov	lr, pc				@ capture return pc
530	movs	pc, lr				@ jump to next instruction &
531						@ switch modes.
532	.endm
533
534	.macro get_bad_stack_swi
535	sub	r13, r13, #4			@ space on current stack for
536						@ scratch reg.
537	str	r0, [r13]			@ save R0's value.
538#if defined(CONFIG_SYS_ARM_WITHOUT_RELOC)
539	ldr	r0, _armboot_start		@ get data regions start
540	sub	r0, r0, #(CONFIG_SYS_MALLOC_LEN)	@ move past malloc pool
541	sub	r0, r0, #(GENERATED_GBL_DATA_SIZE + 8)	@ move past gbl and a couple
542#else
543	ldr	r0, IRQ_STACK_START_IN		@ get data regions start
544						@ spots for abort stack
545#endif
546	str	lr, [r0]			@ save caller lr in position 0
547						@ of saved stack
548	mrs	r0, spsr			@ get the spsr
549	str	lr, [r0, #4]			@ save spsr in position 1 of
550						@ saved stack
551	ldr	r0, [r13]			@ restore r0
552	add	r13, r13, #4			@ pop stack entry
553	.endm
554
555	.macro get_irq_stack			@ setup IRQ stack
556	ldr	sp, IRQ_STACK_START
557	.endm
558
559	.macro get_fiq_stack			@ setup FIQ stack
560	ldr	sp, FIQ_STACK_START
561	.endm
562
563/*
564 * exception handlers
565 */
566	.align	5
567undefined_instruction:
568	get_bad_stack
569	bad_save_user_regs
570	bl	do_undefined_instruction
571
572	.align	5
573software_interrupt:
574	get_bad_stack_swi
575	bad_save_user_regs
576	bl	do_software_interrupt
577
578	.align	5
579prefetch_abort:
580	get_bad_stack
581	bad_save_user_regs
582	bl	do_prefetch_abort
583
584	.align	5
585data_abort:
586	get_bad_stack
587	bad_save_user_regs
588	bl	do_data_abort
589
590	.align	5
591not_used:
592	get_bad_stack
593	bad_save_user_regs
594	bl	do_not_used
595
596#ifdef CONFIG_USE_IRQ
597
598	.align	5
599irq:
600	get_irq_stack
601	irq_save_user_regs
602	bl	do_irq
603	irq_restore_user_regs
604
605	.align	5
606fiq:
607	get_fiq_stack
608	/* someone ought to write a more effective fiq_save_user_regs */
609	irq_save_user_regs
610	bl	do_fiq
611	irq_restore_user_regs
612
613#else
614
615	.align	5
616irq:
617	get_bad_stack
618	bad_save_user_regs
619	bl	do_irq
620
621	.align	5
622fiq:
623	get_bad_stack
624	bad_save_user_regs
625	bl	do_fiq
626
627#endif
628