xref: /openbmc/u-boot/arch/arm/cpu/sa1100/start.S (revision 84ad6884) 
1/*
2 *  armboot - Startup Code for SA1100 CPU
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 Z�pke <azu@sysgo.de>
8 *
9 * See file CREDITS for list of people who contributed to this
10 * project.
11 *
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License as
14 * published by the Free Software Foundation; either version 2 of
15 * the License, or (at your option) any later version.
16 *
17 * This program is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
20 * GNU General Public License for more details.
21 *
22 * You should have received a copy of the GNU General Public License
23 * along with this program; if not, write to the Free Software
24 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
25 * MA 02111-1307 USA
26 */
27
28
29#include <config.h>
30#include <version.h>
31
32
33/*
34 *************************************************************************
35 *
36 * Jump vector table as in table 3.1 in [1]
37 *
38 *************************************************************************
39 */
40
41
42.globl _start
43_start:	b       reset
44	ldr	pc, _undefined_instruction
45	ldr	pc, _software_interrupt
46	ldr	pc, _prefetch_abort
47	ldr	pc, _data_abort
48	ldr	pc, _not_used
49	ldr	pc, _irq
50	ldr	pc, _fiq
51
52_undefined_instruction:	.word undefined_instruction
53_software_interrupt:	.word software_interrupt
54_prefetch_abort:	.word prefetch_abort
55_data_abort:		.word data_abort
56_not_used:		.word not_used
57_irq:			.word irq
58_fiq:			.word fiq
59
60	.balignl 16,0xdeadbeef
61
62
63/*
64 *************************************************************************
65 *
66 * Startup Code (reset vector)
67 *
68 * do important init only if we don't start from memory!
69 * relocate armboot to ram
70 * setup stack
71 * jump to second stage
72 *
73 *************************************************************************
74 */
75
76_TEXT_BASE:
77	.word	TEXT_BASE
78
79.globl _armboot_start
80_armboot_start:
81	.word _start
82
83/*
84 * These are defined in the board-specific linker script.
85 */
86.globl _bss_start
87_bss_start:
88	.word __bss_start
89
90.globl _bss_end
91_bss_end:
92	.word _end
93
94#ifdef CONFIG_USE_IRQ
95/* IRQ stack memory (calculated at run-time) */
96.globl IRQ_STACK_START
97IRQ_STACK_START:
98	.word	0x0badc0de
99
100/* IRQ stack memory (calculated at run-time) */
101.globl FIQ_STACK_START
102FIQ_STACK_START:
103	.word 0x0badc0de
104#endif
105
106
107/*
108 * the actual reset code
109 */
110
111reset:
112	/*
113	 * set the cpu to SVC32 mode
114	 */
115	mrs	r0,cpsr
116	bic	r0,r0,#0x1f
117	orr	r0,r0,#0x13
118	msr	cpsr,r0
119
120	/*
121	 * we do sys-critical inits only at reboot,
122	 * not when booting from ram!
123	 */
124#ifndef CONFIG_SKIP_LOWLEVEL_INIT
125	bl	cpu_init_crit
126#endif
127
128#ifndef CONFIG_SKIP_RELOCATE_UBOOT
129relocate:				/* relocate U-Boot to RAM	    */
130	adr	r0, _start		/* r0 <- current position of code   */
131	ldr	r1, _TEXT_BASE		/* test if we run from flash or RAM */
132	cmp     r0, r1                  /* don't reloc during debug         */
133	beq     stack_setup
134
135	ldr	r2, _armboot_start
136	ldr	r3, _bss_start
137	sub	r2, r3, r2		/* r2 <- size of armboot            */
138	add	r2, r0, r2		/* r2 <- source end address         */
139
140copy_loop:
141	ldmia	r0!, {r3-r10}		/* copy from source address [r0]    */
142	stmia	r1!, {r3-r10}		/* copy to   target address [r1]    */
143	cmp	r0, r2			/* until source end addreee [r2]    */
144	ble	copy_loop
145#endif	/* CONFIG_SKIP_RELOCATE_UBOOT */
146
147	/* Set up the stack						    */
148stack_setup:
149	ldr	r0, _TEXT_BASE		/* upper 128 KiB: relocated uboot   */
150	sub	r0, r0, #CONFIG_SYS_MALLOC_LEN	/* malloc area                      */
151	sub	r0, r0, #CONFIG_SYS_GBL_DATA_SIZE /* bdinfo                        */
152#ifdef CONFIG_USE_IRQ
153	sub	r0, r0, #(CONFIG_STACKSIZE_IRQ+CONFIG_STACKSIZE_FIQ)
154#endif
155	sub	sp, r0, #12		/* leave 3 words for abort-stack    */
156
157clear_bss:
158	ldr	r0, _bss_start		/* find start of bss segment        */
159	ldr	r1, _bss_end		/* stop here                        */
160	mov	r2, #0x00000000		/* clear                            */
161
162clbss_l:str	r2, [r0]		/* clear loop...                    */
163	add	r0, r0, #4
164	cmp	r0, r1
165	ble	clbss_l
166
167	ldr	pc, _start_armboot
168
169_start_armboot:	.word start_armboot
170
171
172/*
173 *************************************************************************
174 *
175 * CPU_init_critical registers
176 *
177 * setup important registers
178 * setup memory timing
179 *
180 *************************************************************************
181 */
182
183
184/* Interupt-Controller base address */
185IC_BASE:	.word	0x90050000
186#define ICMR	0x04
187
188
189/* Reset-Controller */
190RST_BASE:		.word   0x90030000
191#define RSRR	0x00
192#define RCSR	0x04
193
194
195/* PWR */
196PWR_BASE:		.word   0x90020000
197#define PSPR    0x08
198#define PPCR    0x14
199cpuspeed:		.word   CONFIG_SYS_CPUSPEED
200
201
202cpu_init_crit:
203	/*
204	 * mask all IRQs
205	 */
206	ldr	r0, IC_BASE
207	mov	r1, #0x00
208	str	r1, [r0, #ICMR]
209
210	/* set clock speed */
211	ldr	r0, PWR_BASE
212	ldr	r1, cpuspeed
213	str	r1, [r0, #PPCR]
214
215	/*
216	 * before relocating, we have to setup RAM timing
217	 * because memory timing is board-dependend, you will
218	 * find a lowlevel_init.S in your board directory.
219	 */
220	mov	ip,	lr
221	bl	lowlevel_init
222	mov	lr,	ip
223
224	/*
225	 * disable MMU stuff and enable I-cache
226	 */
227	mrc	p15,0,r0,c1,c0
228	bic	r0, r0, #0x00002000	@ clear bit 13 (X)
229	bic	r0, r0, #0x0000000f	@ clear bits 3-0 (WCAM)
230	orr	r0, r0, #0x00001000	@ set bit 12 (I) Icache
231	orr	r0, r0, #0x00000002	@ set bit 2 (A) Align
232	mcr	p15,0,r0,c1,c0
233
234	/*
235	 * flush v4 I/D caches
236	 */
237	mov	r0, #0
238	mcr	p15, 0, r0, c7, c7, 0	/* flush v3/v4 cache */
239	mcr	p15, 0, r0, c8, c7, 0	/* flush v4 TLB */
240
241	mov	pc, lr
242
243
244/*
245 *************************************************************************
246 *
247 * Interrupt handling
248 *
249 *************************************************************************
250 */
251
252@
253@ IRQ stack frame.
254@
255#define S_FRAME_SIZE	72
256
257#define S_OLD_R0	68
258#define S_PSR		64
259#define S_PC		60
260#define S_LR		56
261#define S_SP		52
262
263#define S_IP		48
264#define S_FP		44
265#define S_R10		40
266#define S_R9		36
267#define S_R8		32
268#define S_R7		28
269#define S_R6		24
270#define S_R5		20
271#define S_R4		16
272#define S_R3		12
273#define S_R2		8
274#define S_R1		4
275#define S_R0		0
276
277#define MODE_SVC 0x13
278#define I_BIT	 0x80
279
280/*
281 * use bad_save_user_regs for abort/prefetch/undef/swi ...
282 * use irq_save_user_regs / irq_restore_user_regs for IRQ/FIQ handling
283 */
284
285	.macro	bad_save_user_regs
286	sub	sp, sp, #S_FRAME_SIZE
287	stmia	sp, {r0 - r12}			@ Calling r0-r12
288	add     r8, sp, #S_PC
289
290	ldr	r2, _armboot_start
291	sub	r2, r2, #(CONFIG_STACKSIZE+CONFIG_SYS_MALLOC_LEN)
292	sub	r2, r2, #(CONFIG_SYS_GBL_DATA_SIZE+8)  @ set base 2 words into abort stack
293	ldmia	r2, {r2 - r4}                   @ get pc, cpsr, old_r0
294	add	r0, sp, #S_FRAME_SIZE		@ restore sp_SVC
295
296	add	r5, sp, #S_SP
297	mov	r1, lr
298	stmia	r5, {r0 - r4}                   @ save sp_SVC, lr_SVC, pc, cpsr, old_r
299	mov	r0, sp
300	.endm
301
302	.macro	irq_save_user_regs
303	sub	sp, sp, #S_FRAME_SIZE
304	stmia	sp, {r0 - r12}			@ Calling r0-r12
305	add     r8, sp, #S_PC
306	stmdb   r8, {sp, lr}^                   @ Calling SP, LR
307	str     lr, [r8, #0]                    @ Save calling PC
308	mrs     r6, spsr
309	str     r6, [r8, #4]                    @ Save CPSR
310	str     r0, [r8, #8]                    @ Save OLD_R0
311	mov	r0, sp
312	.endm
313
314	.macro	irq_restore_user_regs
315	ldmia	sp, {r0 - lr}^			@ Calling r0 - lr
316	mov	r0, r0
317	ldr	lr, [sp, #S_PC]			@ Get PC
318	add	sp, sp, #S_FRAME_SIZE
319	subs	pc, lr, #4			@ return & move spsr_svc into cpsr
320	.endm
321
322	.macro get_bad_stack
323	ldr	r13, _armboot_start		@ setup our mode stack
324	sub	r13, r13, #(CONFIG_STACKSIZE+CONFIG_SYS_MALLOC_LEN)
325	sub	r13, r13, #(CONFIG_SYS_GBL_DATA_SIZE+8) @ reserved a couple spots in abort stack
326
327	str	lr, [r13]			@ save caller lr / spsr
328	mrs	lr, spsr
329	str     lr, [r13, #4]
330
331	mov	r13, #MODE_SVC			@ prepare SVC-Mode
332	msr	spsr_c, r13
333	mov	lr, pc
334	movs	pc, lr
335	.endm
336
337	.macro get_irq_stack			@ setup IRQ stack
338	ldr	sp, IRQ_STACK_START
339	.endm
340
341	.macro get_fiq_stack			@ setup FIQ stack
342	ldr	sp, FIQ_STACK_START
343	.endm
344
345/*
346 * exception handlers
347 */
348	.align  5
349undefined_instruction:
350	get_bad_stack
351	bad_save_user_regs
352	bl	do_undefined_instruction
353
354	.align	5
355software_interrupt:
356	get_bad_stack
357	bad_save_user_regs
358	bl	do_software_interrupt
359
360	.align	5
361prefetch_abort:
362	get_bad_stack
363	bad_save_user_regs
364	bl	do_prefetch_abort
365
366	.align	5
367data_abort:
368	get_bad_stack
369	bad_save_user_regs
370	bl	do_data_abort
371
372	.align	5
373not_used:
374	get_bad_stack
375	bad_save_user_regs
376	bl	do_not_used
377
378#ifdef CONFIG_USE_IRQ
379
380	.align	5
381irq:
382	get_irq_stack
383	irq_save_user_regs
384	bl	do_irq
385	irq_restore_user_regs
386
387	.align	5
388fiq:
389	get_fiq_stack
390	/* someone ought to write a more effiction fiq_save_user_regs */
391	irq_save_user_regs
392	bl	do_fiq
393	irq_restore_user_regs
394
395#else
396
397	.align	5
398irq:
399	get_bad_stack
400	bad_save_user_regs
401	bl	do_irq
402
403	.align	5
404fiq:
405	get_bad_stack
406	bad_save_user_regs
407	bl	do_fiq
408
409#endif
410
411	.align	5
412.globl reset_cpu
413reset_cpu:
414	ldr	r0, RST_BASE
415	mov	r1, #0x0			@ set bit 3-0 ...
416	str	r1, [r0, #RCSR]			@ ... to clear in RCSR
417	mov	r1, #0x1
418	str	r1, [r0, #RSRR]			@ and perform reset
419	b	reset_cpu			@ silly, but repeat endlessly
420