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Diffstat (limited to 'arch/arm/mach-at91/pm.c')
-rw-r--r-- | arch/arm/mach-at91/pm.c | 229 |
1 files changed, 229 insertions, 0 deletions
diff --git a/arch/arm/mach-at91/pm.c b/arch/arm/mach-at91/pm.c new file mode 100644 index 000000000000..b49bfda53d7f --- /dev/null +++ b/arch/arm/mach-at91/pm.c | |||
@@ -0,0 +1,229 @@ | |||
1 | /* | ||
2 | * arch/arm/mach-at91/pm.c | ||
3 | * AT91 Power Management | ||
4 | * | ||
5 | * Copyright (C) 2005 David Brownell | ||
6 | * | ||
7 | * This program is free software; you can redistribute it and/or modify | ||
8 | * it under the terms of the GNU General Public License as published by | ||
9 | * the Free Software Foundation; either version 2 of the License, or | ||
10 | * (at your option) any later version. | ||
11 | */ | ||
12 | |||
13 | #include <linux/pm.h> | ||
14 | #include <linux/sched.h> | ||
15 | #include <linux/proc_fs.h> | ||
16 | #include <linux/pm.h> | ||
17 | #include <linux/interrupt.h> | ||
18 | #include <linux/sysfs.h> | ||
19 | #include <linux/module.h> | ||
20 | #include <linux/platform_device.h> | ||
21 | |||
22 | #include <asm/io.h> | ||
23 | #include <asm/irq.h> | ||
24 | #include <asm/atomic.h> | ||
25 | #include <asm/mach/time.h> | ||
26 | #include <asm/mach/irq.h> | ||
27 | #include <asm/mach-types.h> | ||
28 | |||
29 | #include <asm/arch/at91_pmc.h> | ||
30 | #include <asm/arch/at91rm9200_mc.h> | ||
31 | #include <asm/arch/gpio.h> | ||
32 | #include <asm/arch/cpu.h> | ||
33 | |||
34 | #include "generic.h" | ||
35 | |||
36 | |||
37 | static int at91_pm_valid_state(suspend_state_t state) | ||
38 | { | ||
39 | switch (state) { | ||
40 | case PM_SUSPEND_ON: | ||
41 | case PM_SUSPEND_STANDBY: | ||
42 | case PM_SUSPEND_MEM: | ||
43 | return 1; | ||
44 | |||
45 | default: | ||
46 | return 0; | ||
47 | } | ||
48 | } | ||
49 | |||
50 | |||
51 | static suspend_state_t target_state; | ||
52 | |||
53 | /* | ||
54 | * Called after processes are frozen, but before we shutdown devices. | ||
55 | */ | ||
56 | static int at91_pm_prepare(suspend_state_t state) | ||
57 | { | ||
58 | target_state = state; | ||
59 | return 0; | ||
60 | } | ||
61 | |||
62 | /* | ||
63 | * Verify that all the clocks are correct before entering | ||
64 | * slow-clock mode. | ||
65 | */ | ||
66 | static int at91_pm_verify_clocks(void) | ||
67 | { | ||
68 | unsigned long scsr; | ||
69 | int i; | ||
70 | |||
71 | scsr = at91_sys_read(AT91_PMC_SCSR); | ||
72 | |||
73 | /* USB must not be using PLLB */ | ||
74 | if (cpu_is_at91rm9200()) { | ||
75 | if ((scsr & (AT91RM9200_PMC_UHP | AT91RM9200_PMC_UDP)) != 0) { | ||
76 | pr_debug("AT91: PM - Suspend-to-RAM with USB still active\n"); | ||
77 | return 0; | ||
78 | } | ||
79 | } else if (cpu_is_at91sam9260()) { | ||
80 | #warning "Check SAM9260 USB clocks" | ||
81 | } else if (cpu_is_at91sam9261()) { | ||
82 | #warning "Check SAM9261 USB clocks" | ||
83 | } else if (cpu_is_at91sam9263()) { | ||
84 | #warning "Check SAM9263 USB clocks" | ||
85 | } | ||
86 | |||
87 | #ifdef CONFIG_AT91_PROGRAMMABLE_CLOCKS | ||
88 | /* PCK0..PCK3 must be disabled, or configured to use clk32k */ | ||
89 | for (i = 0; i < 4; i++) { | ||
90 | u32 css; | ||
91 | |||
92 | if ((scsr & (AT91_PMC_PCK0 << i)) == 0) | ||
93 | continue; | ||
94 | |||
95 | css = at91_sys_read(AT91_PMC_PCKR(i)) & AT91_PMC_CSS; | ||
96 | if (css != AT91_PMC_CSS_SLOW) { | ||
97 | pr_debug("AT91: PM - Suspend-to-RAM with PCK%d src %d\n", i, css); | ||
98 | return 0; | ||
99 | } | ||
100 | } | ||
101 | #endif | ||
102 | |||
103 | return 1; | ||
104 | } | ||
105 | |||
106 | /* | ||
107 | * Call this from platform driver suspend() to see how deeply to suspend. | ||
108 | * For example, some controllers (like OHCI) need one of the PLL clocks | ||
109 | * in order to act as a wakeup source, and those are not available when | ||
110 | * going into slow clock mode. | ||
111 | * | ||
112 | * REVISIT: generalize as clk_will_be_available(clk)? Other platforms have | ||
113 | * the very same problem (but not using at91 main_clk), and it'd be better | ||
114 | * to add one generic API rather than lots of platform-specific ones. | ||
115 | */ | ||
116 | int at91_suspend_entering_slow_clock(void) | ||
117 | { | ||
118 | return (target_state == PM_SUSPEND_MEM); | ||
119 | } | ||
120 | EXPORT_SYMBOL(at91_suspend_entering_slow_clock); | ||
121 | |||
122 | |||
123 | static void (*slow_clock)(void); | ||
124 | |||
125 | |||
126 | static int at91_pm_enter(suspend_state_t state) | ||
127 | { | ||
128 | at91_gpio_suspend(); | ||
129 | at91_irq_suspend(); | ||
130 | |||
131 | pr_debug("AT91: PM - wake mask %08x, pm state %d\n", | ||
132 | /* remember all the always-wake irqs */ | ||
133 | (at91_sys_read(AT91_PMC_PCSR) | ||
134 | | (1 << AT91_ID_FIQ) | ||
135 | | (1 << AT91_ID_SYS) | ||
136 | | (at91_extern_irq)) | ||
137 | & at91_sys_read(AT91_AIC_IMR), | ||
138 | state); | ||
139 | |||
140 | switch (state) { | ||
141 | /* | ||
142 | * Suspend-to-RAM is like STANDBY plus slow clock mode, so | ||
143 | * drivers must suspend more deeply: only the master clock | ||
144 | * controller may be using the main oscillator. | ||
145 | */ | ||
146 | case PM_SUSPEND_MEM: | ||
147 | /* | ||
148 | * Ensure that clocks are in a valid state. | ||
149 | */ | ||
150 | if (!at91_pm_verify_clocks()) | ||
151 | goto error; | ||
152 | |||
153 | /* | ||
154 | * Enter slow clock mode by switching over to clk32k and | ||
155 | * turning off the main oscillator; reverse on wakeup. | ||
156 | */ | ||
157 | if (slow_clock) { | ||
158 | slow_clock(); | ||
159 | break; | ||
160 | } else { | ||
161 | /* DEVELOPMENT ONLY */ | ||
162 | pr_info("AT91: PM - no slow clock mode yet ...\n"); | ||
163 | /* FALLTHROUGH leaving master clock alone */ | ||
164 | } | ||
165 | |||
166 | /* | ||
167 | * STANDBY mode has *all* drivers suspended; ignores irqs not | ||
168 | * marked as 'wakeup' event sources; and reduces DRAM power. | ||
169 | * But otherwise it's identical to PM_SUSPEND_ON: cpu idle, and | ||
170 | * nothing fancy done with main or cpu clocks. | ||
171 | */ | ||
172 | case PM_SUSPEND_STANDBY: | ||
173 | /* | ||
174 | * NOTE: the Wait-for-Interrupt instruction needs to be | ||
175 | * in icache so the SDRAM stays in self-refresh mode until | ||
176 | * the wakeup IRQ occurs. | ||
177 | */ | ||
178 | asm("b 1f; .align 5; 1:"); | ||
179 | asm("mcr p15, 0, r0, c7, c10, 4"); /* drain write buffer */ | ||
180 | at91_sys_write(AT91_SDRAMC_SRR, 1); /* self-refresh mode */ | ||
181 | /* fall though to next state */ | ||
182 | |||
183 | case PM_SUSPEND_ON: | ||
184 | asm("mcr p15, 0, r0, c7, c0, 4"); /* wait for interrupt */ | ||
185 | break; | ||
186 | |||
187 | default: | ||
188 | pr_debug("AT91: PM - bogus suspend state %d\n", state); | ||
189 | goto error; | ||
190 | } | ||
191 | |||
192 | pr_debug("AT91: PM - wakeup %08x\n", | ||
193 | at91_sys_read(AT91_AIC_IPR) & at91_sys_read(AT91_AIC_IMR)); | ||
194 | |||
195 | error: | ||
196 | target_state = PM_SUSPEND_ON; | ||
197 | at91_irq_resume(); | ||
198 | at91_gpio_resume(); | ||
199 | return 0; | ||
200 | } | ||
201 | |||
202 | |||
203 | static struct pm_ops at91_pm_ops ={ | ||
204 | .pm_disk_mode = 0, | ||
205 | .valid = at91_pm_valid_state, | ||
206 | .prepare = at91_pm_prepare, | ||
207 | .enter = at91_pm_enter, | ||
208 | }; | ||
209 | |||
210 | static int __init at91_pm_init(void) | ||
211 | { | ||
212 | printk("AT91: Power Management\n"); | ||
213 | |||
214 | #ifdef CONFIG_AT91_PM_SLOW_CLOCK | ||
215 | /* REVISIT allocations of SRAM should be dynamically managed. | ||
216 | * FIQ handlers and other components will want SRAM/TCM too... | ||
217 | */ | ||
218 | slow_clock = (void *) (AT91_VA_BASE_SRAM + (3 * SZ_4K)); | ||
219 | memcpy(slow_clock, at91rm9200_slow_clock, at91rm9200_slow_clock_sz); | ||
220 | #endif | ||
221 | |||
222 | /* Disable SDRAM low-power mode. Cannot be used with self-refresh. */ | ||
223 | at91_sys_write(AT91_SDRAMC_LPR, 0); | ||
224 | |||
225 | pm_set_ops(&at91_pm_ops); | ||
226 | |||
227 | return 0; | ||
228 | } | ||
229 | arch_initcall(at91_pm_init); | ||