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/*
* drivers/acpi/device_pm.c - ACPI device power management routines.
*
* Copyright (C) 2012, Intel Corp.
* Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as published
* by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*/
#include <linux/device.h>
#include <linux/export.h>
#include <linux/mutex.h>
#include <linux/pm_qos.h>
#include <acpi/acpi.h>
#include <acpi/acpi_bus.h>
static DEFINE_MUTEX(acpi_pm_notifier_lock);
/**
* acpi_add_pm_notifier - Register PM notifier for given ACPI device.
* @adev: ACPI device to add the notifier for.
* @context: Context information to pass to the notifier routine.
*
* NOTE: @adev need not be a run-wake or wakeup device to be a valid source of
* PM wakeup events. For example, wakeup events may be generated for bridges
* if one of the devices below the bridge is signaling wakeup, even if the
* bridge itself doesn't have a wakeup GPE associated with it.
*/
acpi_status acpi_add_pm_notifier(struct acpi_device *adev,
acpi_notify_handler handler, void *context)
{
acpi_status status = AE_ALREADY_EXISTS;
mutex_lock(&acpi_pm_notifier_lock);
if (adev->wakeup.flags.notifier_present)
goto out;
status = acpi_install_notify_handler(adev->handle,
ACPI_SYSTEM_NOTIFY,
handler, context);
if (ACPI_FAILURE(status))
goto out;
adev->wakeup.flags.notifier_present = true;
out:
mutex_unlock(&acpi_pm_notifier_lock);
return status;
}
/**
* acpi_remove_pm_notifier - Unregister PM notifier from given ACPI device.
* @adev: ACPI device to remove the notifier from.
*/
acpi_status acpi_remove_pm_notifier(struct acpi_device *adev,
acpi_notify_handler handler)
{
acpi_status status = AE_BAD_PARAMETER;
mutex_lock(&acpi_pm_notifier_lock);
if (!adev->wakeup.flags.notifier_present)
goto out;
status = acpi_remove_notify_handler(adev->handle,
ACPI_SYSTEM_NOTIFY,
handler);
if (ACPI_FAILURE(status))
goto out;
adev->wakeup.flags.notifier_present = false;
out:
mutex_unlock(&acpi_pm_notifier_lock);
return status;
}
/**
* acpi_device_power_state - Get preferred power state of ACPI device.
* @dev: Device whose preferred target power state to return.
* @adev: ACPI device node corresponding to @dev.
* @target_state: System state to match the resultant device state.
* @d_max_in: Deepest low-power state to take into consideration.
* @d_min_p: Location to store the upper limit of the allowed states range.
* Return value: Preferred power state of the device on success, -ENODEV
* (if there's no 'struct acpi_device' for @dev) or -EINVAL on failure
*
* Find the lowest power (highest number) ACPI device power state that the
* device can be in while the system is in the state represented by
* @target_state. If @d_min_p is set, the highest power (lowest number) device
* power state that @dev can be in for the given system sleep state is stored
* at the location pointed to by it.
*
* Callers must ensure that @dev and @adev are valid pointers and that @adev
* actually corresponds to @dev before using this function.
*/
int acpi_device_power_state(struct device *dev, struct acpi_device *adev,
u32 target_state, int d_max_in, int *d_min_p)
{
char acpi_method[] = "_SxD";
unsigned long long d_min, d_max;
bool wakeup = false;
if (d_max_in < ACPI_STATE_D0 || d_max_in > ACPI_STATE_D3)
return -EINVAL;
if (d_max_in > ACPI_STATE_D3_HOT) {
enum pm_qos_flags_status stat;
stat = dev_pm_qos_flags(dev, PM_QOS_FLAG_NO_POWER_OFF);
if (stat == PM_QOS_FLAGS_ALL)
d_max_in = ACPI_STATE_D3_HOT;
}
acpi_method[2] = '0' + target_state;
/*
* If the sleep state is S0, the lowest limit from ACPI is D3,
* but if the device has _S0W, we will use the value from _S0W
* as the lowest limit from ACPI. Finally, we will constrain
* the lowest limit with the specified one.
*/
d_min = ACPI_STATE_D0;
d_max = ACPI_STATE_D3;
/*
* If present, _SxD methods return the minimum D-state (highest power
* state) we can use for the corresponding S-states. Otherwise, the
* minimum D-state is D0 (ACPI 3.x).
*
* NOTE: We rely on acpi_evaluate_integer() not clobbering the integer
* provided -- that's our fault recovery, we ignore retval.
*/
if (target_state > ACPI_STATE_S0) {
acpi_evaluate_integer(adev->handle, acpi_method, NULL, &d_min);
wakeup = device_may_wakeup(dev) && adev->wakeup.flags.valid
&& adev->wakeup.sleep_state >= target_state;
} else if (dev_pm_qos_flags(dev, PM_QOS_FLAG_REMOTE_WAKEUP) !=
PM_QOS_FLAGS_NONE) {
wakeup = adev->wakeup.flags.valid;
}
/*
* If _PRW says we can wake up the system from the target sleep state,
* the D-state returned by _SxD is sufficient for that (we assume a
* wakeup-aware driver if wake is set). Still, if _SxW exists
* (ACPI 3.x), it should return the maximum (lowest power) D-state that
* can wake the system. _S0W may be valid, too.
*/
if (wakeup) {
acpi_status status;
acpi_method[3] = 'W';
status = acpi_evaluate_integer(adev->handle, acpi_method, NULL,
&d_max);
if (ACPI_FAILURE(status)) {
if (target_state != ACPI_STATE_S0 ||
status != AE_NOT_FOUND)
d_max = d_min;
} else if (d_max < d_min) {
/* Warn the user of the broken DSDT */
printk(KERN_WARNING "ACPI: Wrong value from %s\n",
acpi_method);
/* Sanitize it */
d_min = d_max;
}
}
if (d_max_in < d_min)
return -EINVAL;
if (d_min_p)
*d_min_p = d_min;
/* constrain d_max with specified lowest limit (max number) */
if (d_max > d_max_in) {
for (d_max = d_max_in; d_max > d_min; d_max--) {
if (adev->power.states[d_max].flags.valid)
break;
}
}
return d_max;
}
EXPORT_SYMBOL_GPL(acpi_device_power_state);
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