summaryrefslogtreecommitdiff
path: root/arch/arm/mach-omap2/sleep33xx.S
blob: 47a816468cdb45a2cf55b3751dfd8dd82c1c40c3 (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
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Low level suspend code for AM33XX SoCs
 *
 * Copyright (C) 2012-2018 Texas Instruments Incorporated - http://www.ti.com/
 *	Dave Gerlach, Vaibhav Bedia
 */

#include <generated/ti-pm-asm-offsets.h>
#include <linux/linkage.h>
#include <linux/platform_data/pm33xx.h>
#include <linux/ti-emif-sram.h>
#include <asm/assembler.h>
#include <asm/memory.h>

#include "iomap.h"
#include "cm33xx.h"

#define AM33XX_CM_CLKCTRL_MODULESTATE_DISABLED			0x00030000
#define AM33XX_CM_CLKCTRL_MODULEMODE_DISABLE			0x0003
#define AM33XX_CM_CLKCTRL_MODULEMODE_ENABLE			0x0002

/* replicated define because linux/bitops.h cannot be included in assembly */
#define BIT(nr)			(1 << (nr))

	.arm
	.align 3

ENTRY(am33xx_do_wfi)
	stmfd	sp!, {r4 - r11, lr}	@ save registers on stack

	/* Save wfi_flags arg to data space */
	mov	r4, r0
	adr	r3, am33xx_pm_ro_sram_data
	ldr	r2, [r3, #AMX3_PM_RO_SRAM_DATA_VIRT_OFFSET]
	str	r4, [r2, #AMX3_PM_WFI_FLAGS_OFFSET]

	/* Only flush cache is we know we are losing MPU context */
	tst	r4, #WFI_FLAG_FLUSH_CACHE
	beq	cache_skip_flush

	/*
	 * Flush all data from the L1 and L2 data cache before disabling
	 * SCTLR.C bit.
	 */
	ldr	r1, kernel_flush
	blx	r1

	/*
	 * Clear the SCTLR.C bit to prevent further data cache
	 * allocation. Clearing SCTLR.C would make all the data accesses
	 * strongly ordered and would not hit the cache.
	 */
	mrc	p15, 0, r0, c1, c0, 0
	bic	r0, r0, #(1 << 2)	@ Disable the C bit
	mcr	p15, 0, r0, c1, c0, 0
	isb

	/*
	 * Invalidate L1 and L2 data cache.
	 */
	ldr	r1, kernel_flush
	blx	r1

	adr	r3, am33xx_pm_ro_sram_data
	ldr	r2, [r3, #AMX3_PM_RO_SRAM_DATA_VIRT_OFFSET]
	ldr	r4, [r2, #AMX3_PM_WFI_FLAGS_OFFSET]

cache_skip_flush:
	/* Check if we want self refresh */
	tst	r4, #WFI_FLAG_SELF_REFRESH
	beq	emif_skip_enter_sr

	adr	r9, am33xx_emif_sram_table

	ldr	r3, [r9, #EMIF_PM_ENTER_SR_OFFSET]
	blx	r3

emif_skip_enter_sr:
	/* Only necessary if PER is losing context */
	tst	r4, #WFI_FLAG_SAVE_EMIF
	beq	emif_skip_save

	ldr	r3, [r9, #EMIF_PM_SAVE_CONTEXT_OFFSET]
	blx	r3

emif_skip_save:
	/* Only can disable EMIF if we have entered self refresh */
	tst     r4, #WFI_FLAG_SELF_REFRESH
	beq     emif_skip_disable

	/* Disable EMIF */
	ldr     r1, virt_emif_clkctrl
	ldr     r2, [r1]
	bic     r2, r2, #AM33XX_CM_CLKCTRL_MODULEMODE_DISABLE
	str     r2, [r1]

	ldr	r1, virt_emif_clkctrl
wait_emif_disable:
	ldr	r2, [r1]
	mov	r3, #AM33XX_CM_CLKCTRL_MODULESTATE_DISABLED
	cmp	r2, r3
	bne	wait_emif_disable

emif_skip_disable:
	tst	r4, #WFI_FLAG_WAKE_M3
	beq	wkup_m3_skip

	/*
	 * For the MPU WFI to be registered as an interrupt
	 * to WKUP_M3, MPU_CLKCTRL.MODULEMODE needs to be set
	 * to DISABLED
	 */
	ldr	r1, virt_mpu_clkctrl
	ldr	r2, [r1]
	bic	r2, r2, #AM33XX_CM_CLKCTRL_MODULEMODE_DISABLE
	str	r2, [r1]

wkup_m3_skip:
	/*
	 * Execute an ISB instruction to ensure that all of the
	 * CP15 register changes have been committed.
	 */
	isb

	/*
	 * Execute a barrier instruction to ensure that all cache,
	 * TLB and branch predictor maintenance operations issued
	 * have completed.
	 */
	dsb
	dmb

	/*
	 * Execute a WFI instruction and wait until the
	 * STANDBYWFI output is asserted to indicate that the
	 * CPU is in idle and low power state. CPU can specualatively
	 * prefetch the instructions so add NOPs after WFI. Thirteen
	 * NOPs as per Cortex-A8 pipeline.
	 */
	wfi

	nop
	nop
	nop
	nop
	nop
	nop
	nop
	nop
	nop
	nop
	nop
	nop
	nop

	/* We come here in case of an abort due to a late interrupt */

	/* Set MPU_CLKCTRL.MODULEMODE back to ENABLE */
	ldr	r1, virt_mpu_clkctrl
	mov	r2, #AM33XX_CM_CLKCTRL_MODULEMODE_ENABLE
	str	r2, [r1]

	/* Re-enable EMIF */
	ldr	r1, virt_emif_clkctrl
	mov	r2, #AM33XX_CM_CLKCTRL_MODULEMODE_ENABLE
	str	r2, [r1]
wait_emif_enable:
	ldr	r3, [r1]
	cmp	r2, r3
	bne	wait_emif_enable

	/* Only necessary if PER is losing context */
	tst	r4, #WFI_FLAG_SELF_REFRESH
	beq	emif_skip_exit_sr_abt

	adr	r9, am33xx_emif_sram_table
	ldr	r1, [r9, #EMIF_PM_ABORT_SR_OFFSET]
	blx	r1

emif_skip_exit_sr_abt:
	tst	r4, #WFI_FLAG_FLUSH_CACHE
	beq	cache_skip_restore

	/*
	 * Set SCTLR.C bit to allow data cache allocation
	 */
	mrc	p15, 0, r0, c1, c0, 0
	orr	r0, r0, #(1 << 2)	@ Enable the C bit
	mcr	p15, 0, r0, c1, c0, 0
	isb

cache_skip_restore:
	/* Let the suspend code know about the abort */
	mov	r0, #1
	ldmfd	sp!, {r4 - r11, pc}	@ restore regs and return
ENDPROC(am33xx_do_wfi)

	.align
ENTRY(am33xx_resume_offset)
	.word . - am33xx_do_wfi

ENTRY(am33xx_resume_from_deep_sleep)
	/* Re-enable EMIF */
	ldr	r0, phys_emif_clkctrl
	mov	r1, #AM33XX_CM_CLKCTRL_MODULEMODE_ENABLE
	str	r1, [r0]
wait_emif_enable1:
	ldr	r2, [r0]
	cmp	r1, r2
	bne	wait_emif_enable1

	adr	r9, am33xx_emif_sram_table

	ldr	r1, [r9, #EMIF_PM_RESTORE_CONTEXT_OFFSET]
	blx	r1

	ldr	r1, [r9, #EMIF_PM_EXIT_SR_OFFSET]
	blx	r1

resume_to_ddr:
	/* We are back. Branch to the common CPU resume routine */
	mov	r0, #0
	ldr	pc, resume_addr
ENDPROC(am33xx_resume_from_deep_sleep)

/*
 * Local variables
 */
	.align
kernel_flush:
	.word   v7_flush_dcache_all
virt_mpu_clkctrl:
	.word	AM33XX_CM_MPU_MPU_CLKCTRL
virt_emif_clkctrl:
	.word	AM33XX_CM_PER_EMIF_CLKCTRL
phys_emif_clkctrl:
	.word	(AM33XX_CM_BASE + AM33XX_CM_PER_MOD + \
		AM33XX_CM_PER_EMIF_CLKCTRL_OFFSET)

.align 3
/* DDR related defines */
am33xx_emif_sram_table:
	.space EMIF_PM_FUNCTIONS_SIZE

ENTRY(am33xx_pm_sram)
	.word am33xx_do_wfi
	.word am33xx_do_wfi_sz
	.word am33xx_resume_offset
	.word am33xx_emif_sram_table
	.word am33xx_pm_ro_sram_data

resume_addr:
.word  cpu_resume - PAGE_OFFSET + 0x80000000

.align 3
ENTRY(am33xx_pm_ro_sram_data)
	.space AMX3_PM_RO_SRAM_DATA_SIZE

ENTRY(am33xx_do_wfi_sz)
	.word	. - am33xx_do_wfi