aboutsummaryrefslogtreecommitdiff
path: root/arch/arm/mach-s3c2410/sleep.S
blob: 61768dac7feed7b3ebaada47062d0f71831d2748 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
/* linux/arch/arm/mach-s3c2410/sleep.S
 *
 * Copyright (c) 2004 Simtec Electronics
 *	Ben Dooks <ben@simtec.co.uk>
 *
 * S3C2410 Power Manager (Suspend-To-RAM) support
 *
 * Based on PXA/SA1100 sleep code by:
 *	Nicolas Pitre, (c) 2002 Monta Vista Software Inc
 *	Cliff Brake, (c) 2001
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#include <linux/config.h>
#include <linux/linkage.h>
#include <asm/assembler.h>
#include <asm/hardware.h>
#include <asm/arch/map.h>

#include <asm/arch/regs-gpio.h>
#include <asm/arch/regs-clock.h>
#include <asm/arch/regs-mem.h>
#include <asm/arch/regs-serial.h>

/* CONFIG_DEBUG_RESUME is dangerous if your bootloader does not
 * reset the UART configuration, only enable if you really need this!
*/
//#define CONFIG_DEBUG_RESUME

	.text

	/* s3c2410_cpu_suspend
	 *
	 * put the cpu into sleep mode
	 *
	 * entry:
	 *	r0 = sleep save block
	*/

ENTRY(s3c2410_cpu_suspend)
	stmfd	sp!, { r4 - r12, lr }

	@@ store co-processor registers

	mrc	p15, 0, r4, c15, c1, 0	@ CP access register
	mrc	p15, 0, r5, c13, c0, 0	@ PID
	mrc	p15, 0, r6, c3, c0, 0	@ Domain ID
	mrc	p15, 0, r7, c2, c0, 0	@ translation table base address
	mrc	p15, 0, r8, c2, c0, 0	@ auxiliary control register
	mrc	p15, 0, r9, c1, c0, 0	@ control register

	stmia	r0, { r4 - r13 }

	@@ flush the caches to ensure everything is back out to
	@@ SDRAM before the core powers down

	bl	arm920_flush_kern_cache_all

	@@ prepare cpu to sleep

	ldr	r4, =S3C2410_REFRESH
	ldr	r5, =S3C2410_MISCCR
	ldr	r6, =S3C2410_CLKCON
	ldr	r7, [ r4 ]		@ get REFRESH (and ensure in TLB)
	ldr	r8, [ r5 ]		@ get MISCCR (and ensure in TLB)
	ldr	r9, [ r6 ]		@ get CLKCON (and ensure in TLB)

	orr	r7, r7, #S3C2410_REFRESH_SELF	@ SDRAM sleep command
	orr	r8, r8, #S3C2410_MISCCR_SDSLEEP @ SDRAM power-down signals
	orr	r9, r9, #S3C2410_CLKCON_POWER	@ power down command

	teq	pc, #0			@ first as a trial-run to load cache
	bl	s3c2410_do_sleep
	teq	r0, r0			@ now do it for real
	b	s3c2410_do_sleep	@

	@@ align next bit of code to cache line
	.align	8
s3c2410_do_sleep:
	streq	r7, [ r4 ]			@ SDRAM sleep command
	streq	r8, [ r5 ]			@ SDRAM power-down config
	streq	r9, [ r6 ]			@ CPU sleep
1:	beq	1b
	mov	pc, r14

	@@ return to the caller, after having the MMU
	@@ turned on, this restores the last bits from the
	@@ stack
resume_with_mmu:
	ldmfd	sp!, { r4 - r12, pc }

	.ltorg

	@@ the next bits sit in the .data segment, even though they
	@@ happen to be code... the s3c2410_sleep_save_phys needs to be
	@@ accessed by the resume code before it can restore the MMU.
	@@ This means that the variable has to be close enough for the
	@@ code to read it... since the .text segment needs to be RO,
	@@ the data segment can be the only place to put this code.

	.data

	.global	s3c2410_sleep_save_phys
s3c2410_sleep_save_phys:
	.word	0

	/* s3c2410_cpu_resume
	 *
	 * resume code entry for bootloader to call
	 *
	 * we must put this code here in the data segment as we have no
	 * other way of restoring the stack pointer after sleep, and we
	 * must not write to the code segment (code is read-only)
	*/

ENTRY(s3c2410_cpu_resume)
	mov	r0, #PSR_I_BIT | PSR_F_BIT | MODE_SVC
	msr	cpsr_c, r0

	@@ load UART to allow us to print the two characters for
	@@ resume debug

	mov	r2, #S3C2410_PA_UART & 0xff000000
	orr	r2, r2, #S3C2410_PA_UART & 0xff000

#if 0
	/* SMDK2440 LED set */
	mov	r14, #S3C2410_PA_GPIO
	ldr	r12, [ r14, #0x54 ]
	bic	r12, r12, #3<<4
	orr	r12, r12, #1<<7
	str	r12, [ r14, #0x54 ]
#endif

#ifdef CONFIG_DEBUG_RESUME
	mov	r3, #'L'
	strb	r3, [ r2, #S3C2410_UTXH ]
1001:
	ldrb	r14, [ r3, #S3C2410_UTRSTAT ]
	tst	r14, #S3C2410_UTRSTAT_TXE
	beq	1001b
#endif /* CONFIG_DEBUG_RESUME */

	mov	r1, #0
	mcr	p15, 0, r1, c8, c7, 0		@@ invalidate I & D TLBs
	mcr	p15, 0, r1, c7, c7, 0		@@ invalidate I & D caches

	ldr	r0, s3c2410_sleep_save_phys	@ address of restore block
	ldmia	r0, { r4 - r13 }

	mcr	p15, 0, r4, c15, c1, 0		@ CP access register
	mcr	p15, 0, r5, c13, c0, 0		@ PID
	mcr	p15, 0, r6, c3, c0, 0		@ Domain ID
	mcr	p15, 0, r7, c2, c0, 0		@ translation table base
	mcr	p15, 0, r8, c1, c1, 0		@ auxilliary control

#ifdef CONFIG_DEBUG_RESUME
	mov	r3, #'R'
	strb	r3, [ r2, #S3C2410_UTXH ]
#endif

	ldr	r2, =resume_with_mmu
	mcr	p15, 0, r9, c1, c0, 0		@ turn on MMU, etc
	nop					@ second-to-last before mmu
	mov	pc, r2				@ go back to virtual address

	.ltorg