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Andrew Victor
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Russell King
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--- | ||
refs/heads/master: 6902f523a328bba5af036699b1352389c0746526 | ||
refs/heads/master: 907d6deb625cd7ff5fea3ef4b20dfb6c1c19c3ee |
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/* | ||
* arch/arm/mach-at91rm9200/pm.c | ||
* AT91 Power Management | ||
* | ||
* Copyright (C) 2005 David Brownell | ||
* | ||
* 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. | ||
*/ | ||
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#include <linux/pm.h> | ||
#include <linux/sched.h> | ||
#include <linux/proc_fs.h> | ||
#include <linux/pm.h> | ||
#include <linux/interrupt.h> | ||
#include <linux/sysfs.h> | ||
#include <linux/module.h> | ||
#include <linux/platform_device.h> | ||
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#include <asm/io.h> | ||
#include <asm/irq.h> | ||
#include <asm/atomic.h> | ||
#include <asm/mach/time.h> | ||
#include <asm/mach/irq.h> | ||
#include <asm/mach-types.h> | ||
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#include <asm/arch/gpio.h> | ||
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#include "generic.h" | ||
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static int at91_pm_valid_state(suspend_state_t state) | ||
{ | ||
switch (state) { | ||
case PM_SUSPEND_ON: | ||
case PM_SUSPEND_STANDBY: | ||
case PM_SUSPEND_MEM: | ||
return 1; | ||
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default: | ||
return 0; | ||
} | ||
} | ||
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static suspend_state_t target_state; | ||
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/* | ||
* Called after processes are frozen, but before we shutdown devices. | ||
*/ | ||
static int at91_pm_prepare(suspend_state_t state) | ||
{ | ||
target_state = state; | ||
return 0; | ||
} | ||
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/* | ||
* Verify that all the clocks are correct before entering | ||
* slow-clock mode. | ||
*/ | ||
static int at91_pm_verify_clocks(void) | ||
{ | ||
unsigned long scsr; | ||
int i; | ||
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scsr = at91_sys_read(AT91_PMC_SCSR); | ||
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/* USB must not be using PLLB */ | ||
if ((scsr & (AT91_PMC_UHP | AT91_PMC_UDP)) != 0) { | ||
pr_debug("AT91: PM - Suspend-to-RAM with USB still active\n"); | ||
return 0; | ||
} | ||
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#ifdef CONFIG_AT91_PROGRAMMABLE_CLOCKS | ||
/* PCK0..PCK3 must be disabled, or configured to use clk32k */ | ||
for (i = 0; i < 4; i++) { | ||
u32 css; | ||
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if ((scsr & (AT91_PMC_PCK0 << i)) == 0) | ||
continue; | ||
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css = at91_sys_read(AT91_PMC_PCKR(i)) & AT91_PMC_CSS; | ||
if (css != AT91_PMC_CSS_SLOW) { | ||
pr_debug("AT91: PM - Suspend-to-RAM with PCK%d src %d\n", i, css); | ||
return 0; | ||
} | ||
} | ||
#endif | ||
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return 1; | ||
} | ||
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/* | ||
* Call this from platform driver suspend() to see how deeply to suspend. | ||
* For example, some controllers (like OHCI) need one of the PLL clocks | ||
* in order to act as a wakeup source, and those are not available when | ||
* going into slow clock mode. | ||
* | ||
* REVISIT: generalize as clk_will_be_available(clk)? Other platforms have | ||
* the very same problem (but not using at91 main_clk), and it'd be better | ||
* to add one generic API rather than lots of platform-specific ones. | ||
*/ | ||
int at91_suspend_entering_slow_clock(void) | ||
{ | ||
return (target_state == PM_SUSPEND_MEM); | ||
} | ||
EXPORT_SYMBOL(at91_suspend_entering_slow_clock); | ||
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static void (*slow_clock)(void); | ||
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static int at91_pm_enter(suspend_state_t state) | ||
{ | ||
at91_gpio_suspend(); | ||
at91_irq_suspend(); | ||
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pr_debug("AT91: PM - wake mask %08x, pm state %d\n", | ||
/* remember all the always-wake irqs */ | ||
(at91_sys_read(AT91_PMC_PCSR) | ||
| (1 << AT91_ID_FIQ) | ||
| (1 << AT91_ID_SYS) | ||
| (1 << AT91_ID_IRQ0) | ||
| (1 << AT91_ID_IRQ1) | ||
| (1 << AT91_ID_IRQ2) | ||
| (1 << AT91_ID_IRQ3) | ||
| (1 << AT91_ID_IRQ4) | ||
| (1 << AT91_ID_IRQ5) | ||
| (1 << AT91_ID_IRQ6)) | ||
& at91_sys_read(AT91_AIC_IMR), | ||
state); | ||
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switch (state) { | ||
/* | ||
* Suspend-to-RAM is like STANDBY plus slow clock mode, so | ||
* drivers must suspend more deeply: only the master clock | ||
* controller may be using the main oscillator. | ||
*/ | ||
case PM_SUSPEND_MEM: | ||
/* | ||
* Ensure that clocks are in a valid state. | ||
*/ | ||
if (!at91_pm_verify_clocks()) | ||
goto error; | ||
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/* | ||
* Enter slow clock mode by switching over to clk32k and | ||
* turning off the main oscillator; reverse on wakeup. | ||
*/ | ||
if (slow_clock) { | ||
slow_clock(); | ||
break; | ||
} else { | ||
/* DEVELOPMENT ONLY */ | ||
pr_info("AT91: PM - no slow clock mode yet ...\n"); | ||
/* FALLTHROUGH leaving master clock alone */ | ||
} | ||
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/* | ||
* STANDBY mode has *all* drivers suspended; ignores irqs not | ||
* marked as 'wakeup' event sources; and reduces DRAM power. | ||
* But otherwise it's identical to PM_SUSPEND_ON: cpu idle, and | ||
* nothing fancy done with main or cpu clocks. | ||
*/ | ||
case PM_SUSPEND_STANDBY: | ||
/* | ||
* NOTE: the Wait-for-Interrupt instruction needs to be | ||
* in icache so the SDRAM stays in self-refresh mode until | ||
* the wakeup IRQ occurs. | ||
*/ | ||
asm("b 1f; .align 5; 1:"); | ||
asm("mcr p15, 0, r0, c7, c10, 4"); /* drain write buffer */ | ||
at91_sys_write(AT91_SDRAMC_SRR, 1); /* self-refresh mode */ | ||
/* fall though to next state */ | ||
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case PM_SUSPEND_ON: | ||
asm("mcr p15, 0, r0, c7, c0, 4"); /* wait for interrupt */ | ||
break; | ||
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default: | ||
pr_debug("AT91: PM - bogus suspend state %d\n", state); | ||
goto error; | ||
} | ||
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pr_debug("AT91: PM - wakeup %08x\n", | ||
at91_sys_read(AT91_AIC_IPR) & at91_sys_read(AT91_AIC_IMR)); | ||
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error: | ||
target_state = PM_SUSPEND_ON; | ||
at91_irq_resume(); | ||
at91_gpio_resume(); | ||
return 0; | ||
} | ||
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static struct pm_ops at91_pm_ops ={ | ||
.pm_disk_mode = 0, | ||
.valid = at91_pm_valid_state, | ||
.prepare = at91_pm_prepare, | ||
.enter = at91_pm_enter, | ||
}; | ||
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static int __init at91_pm_init(void) | ||
{ | ||
printk("AT91: Power Management\n"); | ||
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#ifdef CONFIG_AT91_PM_SLOW_CLOCK | ||
/* REVISIT allocations of SRAM should be dynamically managed. | ||
* FIQ handlers and other components will want SRAM/TCM too... | ||
*/ | ||
slow_clock = (void *) (AT91_VA_BASE_SRAM + (3 * SZ_4K)); | ||
memcpy(slow_clock, at91rm9200_slow_clock, at91rm9200_slow_clock_sz); | ||
#endif | ||
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/* Disable SDRAM low-power mode. Cannot be used with self-refresh. */ | ||
at91_sys_write(AT91_SDRAMC_LPR, 0); | ||
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pm_set_ops(&at91_pm_ops); | ||
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return 0; | ||
} | ||
arch_initcall(at91_pm_init); |
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