The API, suspend_again, is supposed to be used by platforms when the
platforms want to execute some code while suspended (wakeup by an alarm
or periodic ticks, run code, suspend again). Because suspend_again is
not called when every device is resumed, but is called right after
suspend_enter() is called, the suspend_again callback should include
device resume and suspend features.
This patch provides two APIs: dpm_partial_resume and
dpm_partial_suspend. They are supposed to be used in suspend_again to
actiavte required devices.
A usage example is:
/* Devices required to run "monitor_something()". */
static device *devs[] = {
&console_serial,
&device_x,
&device_y,
...
};
bool example_suspend_again(void)
{
int error, monitor_result;
if (!wakeup_reason_is_polling())
return false;
dpm_partial_resume(PMSG_RESUME, devs, ARRAY_SIZE(devs));
resume_console();
monitor_result = monitor_something();
suspend_console();
error = dpm_partial_suspend(PMSG_SUSPEND, devs, ARRAY_SIZE(devs));
if (error || monitor_result == ERROR)
return false;
return true;
}
Tested at Exynos4-NURI.
Signed-off-by: MyungJoo Ham <myungjoo.ham@xxxxxxxxxxx>
Signed-off-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
---
drivers/base/power/main.c | 154 +++++++++++++++++++++++++++++++++++++++++++++
include/linux/pm.h | 4 +
2 files changed, 158 insertions(+), 0 deletions(-)
diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index 052dc53..71dc693 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -1082,3 +1082,157 @@ int device_pm_wait_for_dev(struct device *subordinate, struct device *dev)
return async_error;
}
EXPORT_SYMBOL_GPL(device_pm_wait_for_dev);
+
+/**
+ * __dpm_partial_resume - Execute "resume" callbacks for the listed devices.
+ * @state: PM transition being carried out.
+ * @devs: Array of pointers for the devices being resumed
+ * @size: The size of devs array.
+ */
+static void __dpm_partial_resume(pm_message_t state, struct device **devs,
+ int size)
+{
+ int i;
+ struct device *dev;
+
+ for (i = 0; i < size; i++) {
+ int error;
+
+ dev = devs[i];
+ get_device(dev);
+
+ error = device_resume(dev, state, false);
+ if (error)
+ pm_dev_err(dev, state, "", error);
+
+ put_device(dev);
+ }
+}
+
+/**
+ * __dpm_partial_complete - Complete a PM transition for the listed devices.
+ * @state: PM transition being carried out.
+ * @devs: Array of pointers for the devices being resumed
+ * @size: The size of devs array.
+ */
+static void __dpm_partial_complete(pm_message_t state, struct device **devs,
+ int size)
+{
+ int i;
+ struct device *dev;
+
+ for (i = 0; i < size; i++) {
+ dev = devs[i];
+
+ get_device(dev);
+ dev->power.in_suspend = false;
+
+ device_complete(dev, state);
+
+ put_device(dev);
+ }
+}
+
+/**
+ * dpm_partial_resume - Execute "resume" callbacks and complete system
+ * transaction for the chosen devices only.
+ * @state: PM transition being carried out.
+ * @devs: Array of pointers for the devices being resumed
+ * @size: The size of devs array.
+ *
+ * Execute "resume" callbacks for the listed devices and complete the PM
+ * transition of them.
+ *
+ * Because the only a part of devices will be resumed, asynchronous resume
+ * is dropped.
+ */
+void dpm_partial_resume(pm_message_t state, struct device **devs, int size)
+{
+ /* Partial dpm_resume */
+ __dpm_partial_resume(state, devs, size);
+
+ /* Partial dpm_complete */
+ __dpm_partial_complete(state, devs, size);
+}
+EXPORT_SYMBOL_GPL(dpm_partial_resume);
+
+/**
+ * dpm_partial_suspend - Prepare the given devices for PM transition and
+ * suspend them.
+ * @state: PM transition being carried out.
+ * @devs: Array of pointers for the devices being suspended
+ * @size: The size of devs array.
+ *
+ * Prepare the given devices for system PM transition and execute "suspend"
+ * callbacks for them.
+ *
+ * The devs array is iterated in the reversed order to use the same devs
+ * array with dpm_partial_resume().
+ */
+int dpm_partial_suspend(pm_message_t state, struct device **devs, int size)
+{
+ int error = 0, i;
+ struct device *dev;
+
+ /* Partial dpm_prepare */
+ for (i = size - 1; i >= 0; i--) {
+ dev = devs[i];
+
+ get_device(dev);
+
+ pm_runtime_get_noresume(dev);
+ if (pm_runtime_barrier(dev) && device_may_wakeup(dev))
+ pm_wakeup_event(dev, 0);
+
+ pm_runtime_put_sync(dev);
+ error = pm_wakeup_pending() ?
+ -EBUSY : device_prepare(dev, state);
+
+ if (error) {
+ if (error == -EAGAIN) {
+ put_device(dev);
+ error = 0;
+ i++; /* Try Again */
+ continue;
+ }
+ printk(KERN_INFO "PM: Device %s not prepared "
+ "for power transition: code %d\n",
+ dev_name(dev), error);
+ put_device(dev);
+ break;
+ }
+ dev->power.in_suspend = true;
+ put_device(dev);
+ }
+
+ if (error)
+ goto err_prepare;
+
+ /* Partial dpm_suspend */
+ for (i = size - 1; i >= 0; i--) {
+ dev = devs[i];
+
+ get_device(dev);
+
+ /* Synchronous suspend. The list shouldn't be long */
+ error = __device_suspend(dev, pm_transition, false);
+
+ if (error) {
+ pm_dev_err(dev, state, "", error);
+ put_device(dev);
+ break;
+ }
+ put_device(dev);
+ }
+
+ if (!error)
+ return 0;
+
+ __dpm_partial_resume(PMSG_RESUME, devs + i + 1, size - i - 1);
+ i = -1;
+err_prepare:
+ __dpm_partial_complete(PMSG_RESUME, devs + i + 1, size - i - 1);
+
+ return error;
+}
+EXPORT_SYMBOL_GPL(dpm_partial_suspend);
diff --git a/include/linux/pm.h b/include/linux/pm.h
index 512e091..b407762 100644
--- a/include/linux/pm.h
+++ b/include/linux/pm.h
@@ -540,10 +540,14 @@ static inline int sysdev_resume(void) { return 0; }
extern void device_pm_lock(void);
extern void dpm_resume_noirq(pm_message_t state);
extern void dpm_resume_end(pm_message_t state);
+extern void dpm_partial_resume(pm_message_t state, struct device **devs,
+ int size);
extern void device_pm_unlock(void);
extern int dpm_suspend_noirq(pm_message_t state);
extern int dpm_suspend_start(pm_message_t state);
+extern int dpm_partial_suspend(pm_message_t state, struct device **devs,
+ int size);
extern void __suspend_report_result(const char *function, void *fn, int ret);
--
1.7.4.1
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