1/*
2 * Low-level PXA250/210 sleep/wakeUp support
3 *
4 * Initial SA1110 code:
5 * Copyright (c) 2001 Cliff Brake <cbrake@accelent.com>
6 *
7 * Adapted for PXA by Nicolas Pitre:
8 * Copyright (c) 2002 Monta Vista Software, Inc.
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.
12 */
13
14#include <linux/linkage.h>
15#include <asm/assembler.h>
16#include "smemc.h"
17#include "pxa2xx-regs.h"
18
19#define MDREFR_KDIV 0x200a4000 // all banks
20#define CCCR_SLEEP 0x00000107 // L=7 2N=2 A=0 PPDIS=0 CPDIS=0
21#define CCCR_N_MASK 0x00000380
22#define CCCR_M_MASK 0x00000060
23#define CCCR_L_MASK 0x0000001f
24 .text
25
26#ifdef CONFIG_PXA3xx
27/*
28 * pxa3xx_finish_suspend() - forces CPU into sleep state (S2D3C4)
29 */
30ENTRY(pxa3xx_finish_suspend)
31 mov r0, #0x06 @ S2D3C4 mode
32 mcr p14, 0, r0, c7, c0, 0 @ enter sleep
33
3420: b 20b @ waiting for sleep
35#endif /* CONFIG_PXA3xx */
36
37#ifdef CONFIG_PXA27x
38/*
39 * pxa27x_finish_suspend()
40 *
41 * Forces CPU into sleep state.
42 *
43 * r0 = value for PWRMODE M field for desired sleep state
44 */
45ENTRY(pxa27x_finish_suspend)
46 @ Put the processor to sleep
47 @ (also workaround for sighting 28071)
48
49 @ prepare value for sleep mode
50 mov r1, r0 @ sleep mode
51
52 @ prepare pointer to physical address 0 (virtual mapping in generic.c)
53 mov r2, #UNCACHED_PHYS_0
54
55 @ prepare SDRAM refresh settings
56 ldr r4, =MDREFR
57 ldr r5, [r4]
58
59 @ enable SDRAM self-refresh mode
60 orr r5, r5, #MDREFR_SLFRSH
61
62 @ set SDCLKx divide-by-2 bits (this is part of a workaround for Errata 50)
63 ldr r6, =MDREFR_KDIV
64 orr r5, r5, r6
65
66 @ Intel PXA270 Specification Update notes problems sleeping
67 @ with core operating above 91 MHz
68 @ (see Errata 50, ...processor does not exit from sleep...)
69
70 ldr r6, =CCCR
71 ldr r8, [r6] @ keep original value for resume
72
73 ldr r7, =CCCR_SLEEP @ prepare CCCR sleep value
74 mov r0, #0x2 @ prepare value for CLKCFG
75
76 @ align execution to a cache line
77 b pxa_cpu_do_suspend
78#endif
79
80#ifdef CONFIG_PXA25x
81/*
82 * pxa25x_finish_suspend()
83 *
84 * Forces CPU into sleep state.
85 *
86 * r0 = value for PWRMODE M field for desired sleep state
87 */
88
89ENTRY(pxa25x_finish_suspend)
90 @ prepare value for sleep mode
91 mov r1, r0 @ sleep mode
92
93 @ prepare pointer to physical address 0 (virtual mapping in generic.c)
94 mov r2, #UNCACHED_PHYS_0
95
96 @ prepare SDRAM refresh settings
97 ldr r4, =MDREFR
98 ldr r5, [r4]
99
100 @ enable SDRAM self-refresh mode
101 orr r5, r5, #MDREFR_SLFRSH
102
103 @ Intel PXA255 Specification Update notes problems
104 @ about suspending with PXBus operating above 133MHz
105 @ (see Errata 31, GPIO output signals, ... unpredictable in sleep
106 @
107 @ We keep the change-down close to the actual suspend on SDRAM
108 @ as possible to eliminate messing about with the refresh clock
109 @ as the system will restore with the original speed settings
110 @
111 @ Ben Dooks, 13-Sep-2004
112
113 ldr r6, =CCCR
114 ldr r8, [r6] @ keep original value for resume
115
116 @ ensure x1 for run and turbo mode with memory clock
117 bic r7, r8, #CCCR_M_MASK | CCCR_N_MASK
118 orr r7, r7, #(1<<5) | (2<<7)
119
120 @ check that the memory frequency is within limits
121 and r14, r7, #CCCR_L_MASK
122 teq r14, #1
123 bicne r7, r7, #CCCR_L_MASK
124 orrne r7, r7, #1 @@ 99.53MHz
125
126 @ get ready for the change
127
128 @ note, turbo is not preserved over sleep so there is no
129 @ point in preserving it here. we save it on the stack with the
130 @ other CP registers instead.
131 mov r0, #0
132 mcr p14, 0, r0, c6, c0, 0
133 orr r0, r0, #2 @ initiate change bit
134 b pxa_cpu_do_suspend
135#endif
136
137 .ltorg
138 .align 5
139pxa_cpu_do_suspend:
140
141 @ All needed values are now in registers.
142 @ These last instructions should be in cache
143
144 @ initiate the frequency change...
145 str r7, [r6]
146 mcr p14, 0, r0, c6, c0, 0
147
148 @ restore the original cpu speed value for resume
149 str r8, [r6]
150
151 @ need 6 13-MHz cycles before changing PWRMODE
152 @ just set frequency to 91-MHz... 6*91/13 = 42
153
154 mov r0, #42
15510: subs r0, r0, #1
156 bne 10b
157
158 @ Do not reorder...
159 @ Intel PXA270 Specification Update notes problems performing
160 @ external accesses after SDRAM is put in self-refresh mode
161 @ (see Errata 38 ...hangs when entering self-refresh mode)
162
163 @ force address lines low by reading at physical address 0
164 ldr r3, [r2]
165
166 @ put SDRAM into self-refresh
167 str r5, [r4]
168
169 @ enter sleep mode
170 mcr p14, 0, r1, c7, c0, 0 @ PWRMODE
171
17220: b 20b @ loop waiting for sleep
173

source code of linux/arch/arm/mach-pxa/sleep.S