xref: /openbmc/u-boot/arch/arm/cpu/arm720t/start.S (revision 441cac10) 
1/*
2 *  armboot - Startup Code for ARM720 CPU-core
3 *
4 *  Copyright (c) 2001	Marius Gr�ger <mag@sysgo.de>
5 *  Copyright (c) 2002	Alex Z�pke <azu@sysgo.de>
6 *
7 * See file CREDITS for list of people who contributed to this
8 * project.
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License as
12 * published by the Free Software Foundation; either version 2 of
13 * the License, or (at your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the
18 * GNU General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
23 * MA 02111-1307 USA
24 */
25
26
27#include <config.h>
28#include <version.h>
29#include <asm/hardware.h>
30
31/*
32 *************************************************************************
33 *
34 * Jump vector table as in table 3.1 in [1]
35 *
36 *************************************************************************
37 */
38
39
40.globl _start
41_start: b	reset
42	ldr	pc, _undefined_instruction
43	ldr	pc, _software_interrupt
44	ldr	pc, _prefetch_abort
45	ldr	pc, _data_abort
46#ifdef CONFIG_LPC2292
47	.word	0xB4405F76 /* 2's complement of the checksum of the vectors */
48#else
49	ldr	pc, _not_used
50#endif
51	ldr	pc, _irq
52	ldr	pc, _fiq
53
54_undefined_instruction: .word undefined_instruction
55_software_interrupt:	.word software_interrupt
56_prefetch_abort:	.word prefetch_abort
57_data_abort:		.word data_abort
58_not_used:		.word not_used
59_irq:			.word irq
60_fiq:			.word fiq
61
62	.balignl 16,0xdeadbeef
63
64
65/*
66 *************************************************************************
67 *
68 * Startup Code (reset vector)
69 *
70 * do important init only if we don't start from RAM!
71 * relocate armboot to ram
72 * setup stack
73 * jump to second stage
74 *
75 *************************************************************************
76 */
77
78_TEXT_BASE:
79	.word	TEXT_BASE
80
81.globl _armboot_start
82_armboot_start:
83	.word _start
84
85/*
86 * These are defined in the board-specific linker script.
87 */
88.globl _bss_start
89_bss_start:
90	.word __bss_start
91
92.globl _bss_end
93_bss_end:
94	.word _end
95
96#ifdef CONFIG_USE_IRQ
97/* IRQ stack memory (calculated at run-time) */
98.globl IRQ_STACK_START
99IRQ_STACK_START:
100	.word	0x0badc0de
101
102/* IRQ stack memory (calculated at run-time) */
103.globl FIQ_STACK_START
104FIQ_STACK_START:
105	.word 0x0badc0de
106#endif
107
108
109/*
110 * the actual reset code
111 */
112
113reset:
114	/*
115	 * set the cpu to SVC32 mode
116	 */
117	mrs	r0,cpsr
118	bic	r0,r0,#0x1f
119	orr	r0,r0,#0x13
120	msr	cpsr,r0
121
122	/*
123	 * we do sys-critical inits only at reboot,
124	 * not when booting from ram!
125	 */
126#ifndef CONFIG_SKIP_LOWLEVEL_INIT
127	bl	cpu_init_crit
128#endif
129
130#ifdef CONFIG_LPC2292
131	bl	lowlevel_init
132#endif
133
134#ifndef CONFIG_SKIP_RELOCATE_UBOOT
135relocate:				/* relocate U-Boot to RAM	    */
136	adr	r0, _start		/* r0 <- current position of code   */
137	ldr	r1, _TEXT_BASE		/* test if we run from flash or RAM */
138	cmp	r0, r1			/* don't reloc during debug	    */
139	beq	stack_setup
140
141#if TEXT_BASE
142#ifndef CONFIG_LPC2292 /* already done in lowlevel_init */
143	ldr	r2, =0x0		/* Relocate the exception vectors   */
144	cmp	r1, r2			/* and associated data to address   */
145	ldmneia r0!, {r3-r10}		/* 0x0. Do nothing if TEXT_BASE is  */
146	stmneia r2!, {r3-r10}		/* 0x0. Copy the first 15 words.    */
147	ldmneia r0, {r3-r9}
148	stmneia r2, {r3-r9}
149	adrne	r0, _start		/* restore r0			    */
150#endif	/* !CONFIG_LPC2292 */
151#endif
152
153	ldr	r2, _armboot_start
154	ldr	r3, _bss_start
155	sub	r2, r3, r2		/* r2 <- size of armboot	    */
156	add	r2, r0, r2		/* r2 <- source end address	    */
157
158copy_loop:
159	ldmia	r0!, {r3-r10}		/* copy from source address [r0]    */
160	stmia	r1!, {r3-r10}		/* copy to   target address [r1]    */
161	cmp	r0, r2			/* until source end addreee [r2]    */
162	ble	copy_loop
163
164#endif	/* CONFIG_SKIP_RELOCATE_UBOOT */
165
166	/* Set up the stack						    */
167stack_setup:
168	ldr	r0, _TEXT_BASE		/* upper 128 KiB: relocated uboot   */
169	sub	r0, r0, #CONFIG_SYS_MALLOC_LEN /* malloc area			    */
170	sub	r0, r0, #CONFIG_SYS_GBL_DATA_SIZE /* bdinfo			    */
171#ifdef CONFIG_USE_IRQ
172	sub	r0, r0, #(CONFIG_STACKSIZE_IRQ+CONFIG_STACKSIZE_FIQ)
173#endif
174	sub	sp, r0, #12		/* leave 3 words for abort-stack    */
175
176clear_bss:
177	ldr	r0, _bss_start		/* find start of bss segment	    */
178	ldr	r1, _bss_end		/* stop here			    */
179	mov	r2, #0x00000000		/* clear			    */
180
181clbss_l:str	r2, [r0]		/* clear loop...		    */
182	add	r0, r0, #4
183	cmp	r0, r1
184	ble	clbss_l
185
186	ldr	pc, _start_armboot
187
188_start_armboot: .word start_armboot
189
190/*
191 *************************************************************************
192 *
193 * CPU_init_critical registers
194 *
195 * setup important registers
196 * setup memory timing
197 *
198 *************************************************************************
199 */
200
201#if defined(CONFIG_IMPA7) || defined(CONFIG_EP7312) || defined(CONFIG_ARMADILLO)
202
203/* Interupt-Controller base addresses */
204INTMR1:		.word	0x80000280 @ 32 bit size
205INTMR2:		.word	0x80001280 @ 16 bit size
206INTMR3:		.word	0x80002280 @  8 bit size
207
208/* SYSCONs */
209SYSCON1:	.word	0x80000100
210SYSCON2:	.word	0x80001100
211SYSCON3:	.word	0x80002200
212
213#define CLKCTL	       0x6  /* mask */
214#define CLKCTL_18      0x0  /* 18.432 MHz */
215#define CLKCTL_36      0x2  /* 36.864 MHz */
216#define CLKCTL_49      0x4  /* 49.152 MHz */
217#define CLKCTL_73      0x6  /* 73.728 MHz */
218
219#elif defined(CONFIG_LPC2292)
220PLLCFG_ADR:	.word	PLLCFG
221PLLFEED_ADR:	.word	PLLFEED
222PLLCON_ADR:	.word	PLLCON
223PLLSTAT_ADR:	.word	PLLSTAT
224VPBDIV_ADR:	.word	VPBDIV
225MEMMAP_ADR:	.word	MEMMAP
226
227#endif
228
229cpu_init_crit:
230#if defined(CONFIG_IMPA7) || defined(CONFIG_EP7312) || defined(CONFIG_ARMADILLO)
231
232	/*
233	 * mask all IRQs by clearing all bits in the INTMRs
234	 */
235	mov	r1, #0x00
236	ldr	r0, INTMR1
237	str	r1, [r0]
238	ldr	r0, INTMR2
239	str	r1, [r0]
240	ldr	r0, INTMR3
241	str	r1, [r0]
242
243	/*
244	 * flush v4 I/D caches
245	 */
246	mov	r0, #0
247	mcr	p15, 0, r0, c7, c7, 0	/* flush v3/v4 cache */
248	mcr	p15, 0, r0, c8, c7, 0	/* flush v4 TLB */
249
250	/*
251	 * disable MMU stuff and caches
252	 */
253	mrc	p15,0,r0,c1,c0
254	bic	r0, r0, #0x00002300	@ clear bits 13, 9:8 (--V- --RS)
255	bic	r0, r0, #0x0000008f	@ clear bits 7, 3:0 (B--- WCAM)
256	orr	r0, r0, #0x00000002	@ set bit 2 (A) Align
257	mcr	p15,0,r0,c1,c0
258#elif defined(CONFIG_NETARM)
259	/*
260	 * prior to software reset : need to set pin PORTC4 to be *HRESET
261	 */
262	ldr	r0, =NETARM_GEN_MODULE_BASE
263	ldr	r1, =(NETARM_GEN_PORT_MODE(0x10) | \
264			NETARM_GEN_PORT_DIR(0x10))
265	str	r1, [r0, #+NETARM_GEN_PORTC]
266	/*
267	 * software reset : see HW Ref. Guide 8.2.4 : Software Service register
268	 *		    for an explanation of this process
269	 */
270	ldr	r0, =NETARM_GEN_MODULE_BASE
271	ldr	r1, =NETARM_GEN_SW_SVC_RESETA
272	str	r1, [r0, #+NETARM_GEN_SOFTWARE_SERVICE]
273	ldr	r1, =NETARM_GEN_SW_SVC_RESETB
274	str	r1, [r0, #+NETARM_GEN_SOFTWARE_SERVICE]
275	ldr	r1, =NETARM_GEN_SW_SVC_RESETA
276	str	r1, [r0, #+NETARM_GEN_SOFTWARE_SERVICE]
277	ldr	r1, =NETARM_GEN_SW_SVC_RESETB
278	str	r1, [r0, #+NETARM_GEN_SOFTWARE_SERVICE]
279	/*
280	 * setup PLL and System Config
281	 */
282	ldr	r0, =NETARM_GEN_MODULE_BASE
283
284	ldr	r1, =(	NETARM_GEN_SYS_CFG_LENDIAN | \
285			NETARM_GEN_SYS_CFG_BUSFULL | \
286			NETARM_GEN_SYS_CFG_USER_EN | \
287			NETARM_GEN_SYS_CFG_ALIGN_ABORT | \
288			NETARM_GEN_SYS_CFG_BUSARB_INT | \
289			NETARM_GEN_SYS_CFG_BUSMON_EN )
290
291	str	r1, [r0, #+NETARM_GEN_SYSTEM_CONTROL]
292
293#ifndef CONFIG_NETARM_PLL_BYPASS
294	ldr	r1, =(	NETARM_GEN_PLL_CTL_PLLCNT(NETARM_PLL_COUNT_VAL) | \
295			NETARM_GEN_PLL_CTL_POLTST_DEF | \
296			NETARM_GEN_PLL_CTL_INDIV(1) | \
297			NETARM_GEN_PLL_CTL_ICP_DEF | \
298			NETARM_GEN_PLL_CTL_OUTDIV(2) )
299	str	r1, [r0, #+NETARM_GEN_PLL_CONTROL]
300#endif
301
302	/*
303	 * mask all IRQs by clearing all bits in the INTMRs
304	 */
305	mov	r1, #0
306	ldr	r0, =NETARM_GEN_MODULE_BASE
307	str	r1, [r0, #+NETARM_GEN_INTR_ENABLE]
308
309#elif defined(CONFIG_S3C4510B)
310
311	/*
312	 * Mask off all IRQ sources
313	 */
314	ldr	r1, =REG_INTMASK
315	ldr	r0, =0x3FFFFF
316	str	r0, [r1]
317
318	/*
319	 * Disable Cache
320	 */
321	ldr r0, =REG_SYSCFG
322	ldr r1, =0x83ffffa0	/* cache-disabled  */
323	str r1, [r0]
324
325#elif defined(CONFIG_INTEGRATOR) && defined(CONFIG_ARCH_INTEGRATOR)
326	/* No specific initialisation for IntegratorAP/CM720T as yet */
327#elif defined(CONFIG_LPC2292)
328	/* Set-up PLL */
329	mov	r3, #0xAA
330	mov	r4, #0x55
331	/* First disconnect and disable the PLL */
332	ldr	r0, PLLCON_ADR
333	mov	r1, #0x00
334	str	r1, [r0]
335	ldr	r0, PLLFEED_ADR /* start feed sequence */
336	str	r3, [r0]
337	str	r4, [r0]	/* feed sequence done */
338	/* Set new M and P values */
339	ldr	r0, PLLCFG_ADR
340	mov	r1, #0x23	/* M=4 and P=2 */
341	str	r1, [r0]
342	ldr	r0, PLLFEED_ADR /* start feed sequence */
343	str	r3, [r0]
344	str	r4, [r0]	/* feed sequence done */
345	/* Then enable the PLL */
346	ldr	r0, PLLCON_ADR
347	mov	r1, #0x01	/* PLL enable bit */
348	str	r1, [r0]
349	ldr	r0, PLLFEED_ADR /* start feed sequence */
350	str	r3, [r0]
351	str	r4, [r0]	/* feed sequence done */
352	/* Wait for the lock */
353	ldr	r0, PLLSTAT_ADR
354	mov	r1, #0x400	/* lock bit */
355lock_loop:
356	ldr	r2, [r0]
357	and	r2, r1, r2
358	cmp	r2, #0
359	beq	lock_loop
360	/* And finally connect the PLL */
361	ldr	r0, PLLCON_ADR
362	mov	r1, #0x03	/* PLL enable bit and connect bit */
363	str	r1, [r0]
364	ldr	r0, PLLFEED_ADR /* start feed sequence */
365	str	r3, [r0]
366	str	r4, [r0]	/* feed sequence done */
367	/* Set-up VPBDIV register */
368	ldr	r0, VPBDIV_ADR
369	mov	r1, #0x01	/* VPB clock is same as process clock */
370	str	r1, [r0]
371#else
372#error No cpu_init_crit() defined for current CPU type
373#endif
374
375#ifdef CONFIG_ARM7_REVD
376	/* set clock speed */
377	/* !!! we run @ 36 MHz due to a hardware flaw in Rev. D processors */
378	/* !!! not doing DRAM refresh properly! */
379	ldr	r0, SYSCON3
380	ldr	r1, [r0]
381	bic	r1, r1, #CLKCTL
382	orr	r1, r1, #CLKCTL_36
383	str	r1, [r0]
384#endif
385
386#ifndef CONFIG_LPC2292
387	mov	ip, lr
388	/*
389	 * before relocating, we have to setup RAM timing
390	 * because memory timing is board-dependent, you will
391	 * find a lowlevel_init.S in your board directory.
392	 */
393	bl	lowlevel_init
394	mov	lr, ip
395#endif
396
397	mov	pc, lr
398
399
400/*
401 *************************************************************************
402 *
403 * Interrupt handling
404 *
405 *************************************************************************
406 */
407
408@
409@ IRQ stack frame.
410@
411#define S_FRAME_SIZE	72
412
413#define S_OLD_R0	68
414#define S_PSR		64
415#define S_PC		60
416#define S_LR		56
417#define S_SP		52
418
419#define S_IP		48
420#define S_FP		44
421#define S_R10		40
422#define S_R9		36
423#define S_R8		32
424#define S_R7		28
425#define S_R6		24
426#define S_R5		20
427#define S_R4		16
428#define S_R3		12
429#define S_R2		8
430#define S_R1		4
431#define S_R0		0
432
433#define MODE_SVC 0x13
434#define I_BIT	 0x80
435
436/*
437 * use bad_save_user_regs for abort/prefetch/undef/swi ...
438 * use irq_save_user_regs / irq_restore_user_regs for IRQ/FIQ handling
439 */
440
441	.macro	bad_save_user_regs
442	sub	sp, sp, #S_FRAME_SIZE
443	stmia	sp, {r0 - r12}			@ Calling r0-r12
444	add	r8, sp, #S_PC
445
446	ldr	r2, _armboot_start
447	sub	r2, r2, #(CONFIG_STACKSIZE+CONFIG_SYS_MALLOC_LEN)
448	sub	r2, r2, #(CONFIG_SYS_GBL_DATA_SIZE+8)	@ set base 2 words into abort stack
449	ldmia	r2, {r2 - r4}			@ get pc, cpsr, old_r0
450	add	r0, sp, #S_FRAME_SIZE		@ restore sp_SVC
451
452	add	r5, sp, #S_SP
453	mov	r1, lr
454	stmia	r5, {r0 - r4}			@ save sp_SVC, lr_SVC, pc, cpsr, old_r
455	mov	r0, sp
456	.endm
457
458	.macro	irq_save_user_regs
459	sub	sp, sp, #S_FRAME_SIZE
460	stmia	sp, {r0 - r12}			@ Calling r0-r12
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, _armboot_start		@ setup our mode stack
480	sub	r13, r13, #(CONFIG_STACKSIZE+CONFIG_SYS_MALLOC_LEN)
481	sub	r13, r13, #(CONFIG_SYS_GBL_DATA_SIZE+8) @ reserved a couple spots in abort stack
482
483	str	lr, [r13]			@ save caller lr / spsr
484	mrs	lr, spsr
485	str	lr, [r13, #4]
486
487	mov	r13, #MODE_SVC			@ prepare SVC-Mode
488	msr	spsr_c, r13
489	mov	lr, pc
490	movs	pc, lr
491	.endm
492
493	.macro get_irq_stack			@ setup IRQ stack
494	ldr	sp, IRQ_STACK_START
495	.endm
496
497	.macro get_fiq_stack			@ setup FIQ stack
498	ldr	sp, FIQ_STACK_START
499	.endm
500
501/*
502 * exception handlers
503 */
504	.align	5
505undefined_instruction:
506	get_bad_stack
507	bad_save_user_regs
508	bl	do_undefined_instruction
509
510	.align	5
511software_interrupt:
512	get_bad_stack
513	bad_save_user_regs
514	bl	do_software_interrupt
515
516	.align	5
517prefetch_abort:
518	get_bad_stack
519	bad_save_user_regs
520	bl	do_prefetch_abort
521
522	.align	5
523data_abort:
524	get_bad_stack
525	bad_save_user_regs
526	bl	do_data_abort
527
528	.align	5
529not_used:
530	get_bad_stack
531	bad_save_user_regs
532	bl	do_not_used
533
534#ifdef CONFIG_USE_IRQ
535
536	.align	5
537irq:
538	get_irq_stack
539	irq_save_user_regs
540	bl	do_irq
541	irq_restore_user_regs
542
543	.align	5
544fiq:
545	get_fiq_stack
546	/* someone ought to write a more effiction fiq_save_user_regs */
547	irq_save_user_regs
548	bl	do_fiq
549	irq_restore_user_regs
550
551#else
552
553	.align	5
554irq:
555	get_bad_stack
556	bad_save_user_regs
557	bl	do_irq
558
559	.align	5
560fiq:
561	get_bad_stack
562	bad_save_user_regs
563	bl	do_fiq
564
565#endif
566
567#if defined(CONFIG_IMPA7) || defined(CONFIG_EP7312) || defined(CONFIG_ARMADILLO)
568	.align	5
569.globl reset_cpu
570reset_cpu:
571	mov	ip, #0
572	mcr	p15, 0, ip, c7, c7, 0		@ invalidate cache
573	mcr	p15, 0, ip, c8, c7, 0		@ flush TLB (v4)
574	mrc	p15, 0, ip, c1, c0, 0		@ get ctrl register
575	bic	ip, ip, #0x000f			@ ............wcam
576	bic	ip, ip, #0x2100			@ ..v....s........
577	mcr	p15, 0, ip, c1, c0, 0		@ ctrl register
578	mov	pc, r0
579#elif defined(CONFIG_NETARM)
580	.align	5
581.globl reset_cpu
582reset_cpu:
583	ldr	r1, =NETARM_MEM_MODULE_BASE
584	ldr	r0, [r1, #+NETARM_MEM_CS0_BASE_ADDR]
585	ldr	r1, =0xFFFFF000
586	and	r0, r1, r0
587	ldr	r1, =(relocate-TEXT_BASE)
588	add	r0, r1, r0
589	ldr	r4, =NETARM_GEN_MODULE_BASE
590	ldr	r1, =NETARM_GEN_SW_SVC_RESETA
591	str	r1, [r4, #+NETARM_GEN_SOFTWARE_SERVICE]
592	ldr	r1, =NETARM_GEN_SW_SVC_RESETB
593	str	r1, [r4, #+NETARM_GEN_SOFTWARE_SERVICE]
594	ldr	r1, =NETARM_GEN_SW_SVC_RESETA
595	str	r1, [r4, #+NETARM_GEN_SOFTWARE_SERVICE]
596	ldr	r1, =NETARM_GEN_SW_SVC_RESETB
597	str	r1, [r4, #+NETARM_GEN_SOFTWARE_SERVICE]
598	mov	pc, r0
599#elif defined(CONFIG_S3C4510B)
600/* Nothing done here as reseting the CPU is board specific, depending
601 * on external peripherals such as watchdog timers, etc. */
602#elif defined(CONFIG_INTEGRATOR) && defined(CONFIG_ARCH_INTEGRATOR)
603	/* No specific reset actions for IntegratorAP/CM720T as yet */
604#elif defined(CONFIG_LPC2292)
605	.align	5
606.globl reset_cpu
607reset_cpu:
608	mov	pc, r0
609#else
610#error No reset_cpu() defined for current CPU type
611#endif
612