android_kernel_xiaomi_sm8350/arch/arm/mach-at91/pm.c
Rafael J. Wysocki c697eecebc Suspend: Introduce begin() and end() callbacks
On ACPI systems the target state set by acpi_pm_set_target() is
reset by acpi_pm_finish(), but that need not be called if the
suspend fails.  All platforms that use the .set_target() global
suspend callback are affected by analogous issues.

For this reason, we need an additional global suspend callback that
will reset the target state regardless of whether or not the suspend
is successful.  Also, it is reasonable to rename the .set_target()
callback, since it will be used for a different purpose on ACPI
systems (due to ACPI 1.0x code ordering requirements).

Introduce the global suspend callback .end() to be executed at the
end of the suspend sequence and rename the .set_target() global
suspend callback to .begin().

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>
2008-02-01 18:30:56 -05:00

241 lines
5.8 KiB
C

/*
* arch/arm/mach-at91/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.
*/
#include <linux/suspend.h>
#include <linux/sched.h>
#include <linux/proc_fs.h>
#include <linux/interrupt.h>
#include <linux/sysfs.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#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>
#include <asm/arch/at91_pmc.h>
#include <asm/arch/at91rm9200_mc.h>
#include <asm/arch/gpio.h>
#include <asm/arch/cpu.h>
#include "generic.h"
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;
default:
return 0;
}
}
static suspend_state_t target_state;
/*
* Called after processes are frozen, but before we shutdown devices.
*/
static int at91_pm_begin(suspend_state_t state)
{
target_state = state;
return 0;
}
/*
* Verify that all the clocks are correct before entering
* slow-clock mode.
*/
static int at91_pm_verify_clocks(void)
{
unsigned long scsr;
int i;
scsr = at91_sys_read(AT91_PMC_SCSR);
/* USB must not be using PLLB */
if (cpu_is_at91rm9200()) {
if ((scsr & (AT91RM9200_PMC_UHP | AT91RM9200_PMC_UDP)) != 0) {
pr_debug("AT91: PM - Suspend-to-RAM with USB still active\n");
return 0;
}
} else if (cpu_is_at91sam9260() || cpu_is_at91sam9261() || cpu_is_at91sam9263()) {
if ((scsr & (AT91SAM926x_PMC_UHP | AT91SAM926x_PMC_UDP)) != 0) {
pr_debug("AT91: PM - Suspend-to-RAM with USB still active\n");
return 0;
}
} else if (cpu_is_at91cap9()) {
if ((scsr & AT91CAP9_PMC_UHP) != 0) {
pr_debug("AT91: PM - Suspend-to-RAM with USB still active\n");
return 0;
}
}
#ifdef CONFIG_AT91_PROGRAMMABLE_CLOCKS
/* PCK0..PCK3 must be disabled, or configured to use clk32k */
for (i = 0; i < 4; i++) {
u32 css;
if ((scsr & (AT91_PMC_PCK0 << i)) == 0)
continue;
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
return 1;
}
/*
* 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);
static void (*slow_clock)(void);
static int at91_pm_enter(suspend_state_t state)
{
at91_gpio_suspend();
at91_irq_suspend();
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)
| (at91_extern_irq))
& at91_sys_read(AT91_AIC_IMR),
state);
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;
/*
* 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 */
}
/*
* 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 */
case PM_SUSPEND_ON:
asm("mcr p15, 0, r0, c7, c0, 4"); /* wait for interrupt */
break;
default:
pr_debug("AT91: PM - bogus suspend state %d\n", state);
goto error;
}
pr_debug("AT91: PM - wakeup %08x\n",
at91_sys_read(AT91_AIC_IPR) & at91_sys_read(AT91_AIC_IMR));
error:
target_state = PM_SUSPEND_ON;
at91_irq_resume();
at91_gpio_resume();
return 0;
}
/*
* Called right prior to thawing processes.
*/
static void at91_pm_end(void)
{
target_state = PM_SUSPEND_ON;
}
static struct platform_suspend_ops at91_pm_ops ={
.valid = at91_pm_valid_state,
.begin = at91_pm_begin,
.enter = at91_pm_enter,
.end = at91_pm_end,
};
static int __init at91_pm_init(void)
{
printk("AT91: Power Management\n");
#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
/* Disable SDRAM low-power mode. Cannot be used with self-refresh. */
at91_sys_write(AT91_SDRAMC_LPR, 0);
suspend_set_ops(&at91_pm_ops);
return 0;
}
arch_initcall(at91_pm_init);