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Subject[PATCH v4 1/3] PM / wakeirq: support enabling wake-up irq after runtime_suspend called
Date
When the dedicated wake IRQ is level trigger, and it uses the
device's low-power status as the wakeup source, that means if the
device is not in low-power state, the wake IRQ will be triggered
if enabled; For this case, need enable the wake IRQ after running
the device's ->runtime_suspend() which make it enter low-power state.

e.g.
Assume the wake IRQ is a low level trigger type, and the wakeup
signal comes from the low-power status of the device.
The wakeup signal is low level at running time (0), and becomes
high level when the device enters low-power state (runtime_suspend
(1) is called), a wakeup event at (2) make the device exit low-power
state, then the wakeup signal also becomes low level.

------------------
| ^ ^|
---------------- | | --------------
|<---(0)--->|<--(1)--| (3) (2) (4)

if enable the wake IRQ before running runtime_suspend during (0),
a wake IRQ will arise, it causes resume immediately;
it works if enable wake IRQ ( e.g. at (3) or (4)) after running
->runtime_suspend().

This patch introduces a new status WAKE_IRQ_DEDICATED_REVERSE to
optionally support enabling wake IRQ after running ->runtime_suspend().

Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
---
v4: changes according to Rafael's suggestions
1. rename new flag as WAKE_IRQ_DEDICATED_REVERSE;
2. add __dev_pm_set_dedicated_wake_irq() with flag parameter, then
rebuild dev_pm_set_dedicated_wake_irq() and add new api
dev_pm_set_dedicated_wake_irq_reverse();
3. rename the new added parameter as cond_disable in
dev_pm_disable_wake_irq_check(), and also simplify its flow;
4. modify some comments

v3: add new status suggested by Rafael

v2: add more commit message

Use the falling edge trigger interrupt suggested by Ikjoon [1], it
works well at firstly when only use this related wakeup source, but
encounter issues if use other wakeup sources to wakeup platform as
below steps:
1. use another wakeup source to wake up the suspended system;
2. the consumer's resume() will be called, and exits sleep state;
3. the consumer's wakeup signal will fall into low level, due to
currently the wakeup irq is disabled, the wake-irq is pending;
4. the consumer tries to enter runtime suspend, but there is a
pending wakeup irq, so will resume again, this will repeat
endlessly.

Send out the patch again for further discussion.

[1]: https://patchwork.kernel.org/patch/12190407

---
drivers/base/power/power.h | 7 ++-
drivers/base/power/runtime.c | 6 ++-
drivers/base/power/wakeirq.c | 101 +++++++++++++++++++++++++++--------
include/linux/pm_wakeirq.h | 9 +++-
4 files changed, 96 insertions(+), 27 deletions(-)

diff --git a/drivers/base/power/power.h b/drivers/base/power/power.h
index 54292cdd7808..0eb7f02b3ad5 100644
--- a/drivers/base/power/power.h
+++ b/drivers/base/power/power.h
@@ -25,8 +25,10 @@ extern u64 pm_runtime_active_time(struct device *dev);

#define WAKE_IRQ_DEDICATED_ALLOCATED BIT(0)
#define WAKE_IRQ_DEDICATED_MANAGED BIT(1)
+#define WAKE_IRQ_DEDICATED_REVERSE BIT(2)
#define WAKE_IRQ_DEDICATED_MASK (WAKE_IRQ_DEDICATED_ALLOCATED | \
- WAKE_IRQ_DEDICATED_MANAGED)
+ WAKE_IRQ_DEDICATED_MANAGED | \
+ WAKE_IRQ_DEDICATED_REVERSE)

struct wake_irq {
struct device *dev;
@@ -39,7 +41,8 @@ extern void dev_pm_arm_wake_irq(struct wake_irq *wirq);
extern void dev_pm_disarm_wake_irq(struct wake_irq *wirq);
extern void dev_pm_enable_wake_irq_check(struct device *dev,
bool can_change_status);
-extern void dev_pm_disable_wake_irq_check(struct device *dev);
+extern void dev_pm_disable_wake_irq_check(struct device *dev, bool cond_disable);
+extern void dev_pm_enable_wake_irq_complete(struct device *dev);

#ifdef CONFIG_PM_SLEEP

diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index ec94049442b9..d504cd4ab3cb 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -645,6 +645,8 @@ static int rpm_suspend(struct device *dev, int rpmflags)
if (retval)
goto fail;

+ dev_pm_enable_wake_irq_complete(dev);
+
no_callback:
__update_runtime_status(dev, RPM_SUSPENDED);
pm_runtime_deactivate_timer(dev);
@@ -690,7 +692,7 @@ static int rpm_suspend(struct device *dev, int rpmflags)
return retval;

fail:
- dev_pm_disable_wake_irq_check(dev);
+ dev_pm_disable_wake_irq_check(dev, true);
__update_runtime_status(dev, RPM_ACTIVE);
dev->power.deferred_resume = false;
wake_up_all(&dev->power.wait_queue);
@@ -873,7 +875,7 @@ static int rpm_resume(struct device *dev, int rpmflags)

callback = RPM_GET_CALLBACK(dev, runtime_resume);

- dev_pm_disable_wake_irq_check(dev);
+ dev_pm_disable_wake_irq_check(dev, false);
retval = rpm_callback(callback, dev);
if (retval) {
__update_runtime_status(dev, RPM_SUSPENDED);
diff --git a/drivers/base/power/wakeirq.c b/drivers/base/power/wakeirq.c
index b91a3a9bf9f6..76c163a89104 100644
--- a/drivers/base/power/wakeirq.c
+++ b/drivers/base/power/wakeirq.c
@@ -142,24 +142,7 @@ static irqreturn_t handle_threaded_wake_irq(int irq, void *_wirq)
return IRQ_HANDLED;
}

-/**
- * dev_pm_set_dedicated_wake_irq - Request a dedicated wake-up interrupt
- * @dev: Device entry
- * @irq: Device wake-up interrupt
- *
- * Unless your hardware has separate wake-up interrupts in addition
- * to the device IO interrupts, you don't need this.
- *
- * Sets up a threaded interrupt handler for a device that has
- * a dedicated wake-up interrupt in addition to the device IO
- * interrupt.
- *
- * The interrupt starts disabled, and needs to be managed for
- * the device by the bus code or the device driver using
- * dev_pm_enable_wake_irq() and dev_pm_disable_wake_irq()
- * functions.
- */
-int dev_pm_set_dedicated_wake_irq(struct device *dev, int irq)
+static int __dev_pm_set_dedicated_wake_irq(struct device *dev, int irq, unsigned int flag)
{
struct wake_irq *wirq;
int err;
@@ -197,7 +180,7 @@ int dev_pm_set_dedicated_wake_irq(struct device *dev, int irq)
if (err)
goto err_free_irq;

- wirq->status = WAKE_IRQ_DEDICATED_ALLOCATED;
+ wirq->status = WAKE_IRQ_DEDICATED_ALLOCATED | flag;

return err;

@@ -210,8 +193,57 @@ int dev_pm_set_dedicated_wake_irq(struct device *dev, int irq)

return err;
}
+
+
+/**
+ * dev_pm_set_dedicated_wake_irq - Request a dedicated wake-up interrupt
+ * @dev: Device entry
+ * @irq: Device wake-up interrupt
+ *
+ * Unless your hardware has separate wake-up interrupts in addition
+ * to the device IO interrupts, you don't need this.
+ *
+ * Sets up a threaded interrupt handler for a device that has
+ * a dedicated wake-up interrupt in addition to the device IO
+ * interrupt.
+ *
+ * The interrupt starts disabled, and needs to be managed for
+ * the device by the bus code or the device driver using
+ * dev_pm_enable_wake_irq*() and dev_pm_disable_wake_irq*()
+ * functions.
+ */
+int dev_pm_set_dedicated_wake_irq(struct device *dev, int irq)
+{
+ return __dev_pm_set_dedicated_wake_irq(dev, irq, 0);
+}
EXPORT_SYMBOL_GPL(dev_pm_set_dedicated_wake_irq);

+/**
+ * dev_pm_set_dedicated_wake_irq_reverse - Request a dedicated wake-up interrupt
+ * with setting flag WAKE_IRQ_DEDICATED_REVERSE
+ * @dev: Device entry
+ * @irq: Device wake-up interrupt
+ *
+ * Unless your hardware has separate wake-up interrupts in addition
+ * to the device IO interrupts, you don't need this.
+ *
+ * Sets up a threaded interrupt handler for a device that has a dedicated
+ * wake-up interrupt in addition to the device IO interrupt. It sets
+ * the status of WAKE_IRQ_DEDICATED_REVERSE to tell rpm_suspend()
+ * to enable dedicated wake-up interrupt after running the
+ * ->runtime_suspend()
+ *
+ * The interrupt starts disabled, and needs to be managed for
+ * the device by the bus code or the device driver using
+ * dev_pm_enable_wake_irq*() and dev_pm_disable_wake_irq*()
+ * functions.
+ */
+int dev_pm_set_dedicated_wake_irq_reverse(struct device *dev, int irq)
+{
+ return __dev_pm_set_dedicated_wake_irq(dev, irq, WAKE_IRQ_DEDICATED_REVERSE);
+}
+EXPORT_SYMBOL_GPL(dev_pm_set_dedicated_wake_irq_reverse);
+
/**
* dev_pm_enable_wake_irq - Enable device wake-up interrupt
* @dev: Device
@@ -282,27 +314,54 @@ void dev_pm_enable_wake_irq_check(struct device *dev,
return;

enable:
- enable_irq(wirq->irq);
+ if (!can_change_status || !(wirq->status & WAKE_IRQ_DEDICATED_REVERSE))
+ enable_irq(wirq->irq);
}

/**
* dev_pm_disable_wake_irq_check - Checks and disables wake-up interrupt
* @dev: Device
+ * @cond_disable: if set, also check WAKE_IRQ_DEDICATED_REVERSE
*
* Disables wake-up interrupt conditionally based on status.
* Should be only called from rpm_suspend() and rpm_resume() path.
*/
-void dev_pm_disable_wake_irq_check(struct device *dev)
+void dev_pm_disable_wake_irq_check(struct device *dev, bool cond_disable)
{
struct wake_irq *wirq = dev->power.wakeirq;

if (!wirq || !(wirq->status & WAKE_IRQ_DEDICATED_MASK))
return;

+ if (cond_disable && (wirq->status & WAKE_IRQ_DEDICATED_REVERSE))
+ return;
+
if (wirq->status & WAKE_IRQ_DEDICATED_MANAGED)
disable_irq_nosync(wirq->irq);
}

+/**
+ * dev_pm_enable_wake_irq_complete - enable wake IRQ not enabled before
+ * @dev: Device using the wake IRQ
+ *
+ * Enable wake IRQ conditionally based on status, mainly used if want to
+ * enable wake IRQ after running ->runtime_suspend() which depends on
+ * WAKE_IRQ_DEDICATED_REVERSE.
+ *
+ * Should be only called from rpm_suspend() path.
+ */
+void dev_pm_enable_wake_irq_complete(struct device *dev)
+{
+ struct wake_irq *wirq = dev->power.wakeirq;
+
+ if (!wirq || !(wirq->status & WAKE_IRQ_DEDICATED_MASK))
+ return;
+
+ if (wirq->status & WAKE_IRQ_DEDICATED_MANAGED &&
+ wirq->status & WAKE_IRQ_DEDICATED_REVERSE)
+ enable_irq(wirq->irq);
+}
+
/**
* dev_pm_arm_wake_irq - Arm device wake-up
* @wirq: Device wake-up interrupt
diff --git a/include/linux/pm_wakeirq.h b/include/linux/pm_wakeirq.h
index cd5b62db9084..e63a63aa47a3 100644
--- a/include/linux/pm_wakeirq.h
+++ b/include/linux/pm_wakeirq.h
@@ -17,8 +17,8 @@
#ifdef CONFIG_PM

extern int dev_pm_set_wake_irq(struct device *dev, int irq);
-extern int dev_pm_set_dedicated_wake_irq(struct device *dev,
- int irq);
+extern int dev_pm_set_dedicated_wake_irq(struct device *dev, int irq);
+extern int dev_pm_set_dedicated_wake_irq_reverse(struct device *dev, int irq);
extern void dev_pm_clear_wake_irq(struct device *dev);
extern void dev_pm_enable_wake_irq(struct device *dev);
extern void dev_pm_disable_wake_irq(struct device *dev);
@@ -35,6 +35,11 @@ static inline int dev_pm_set_dedicated_wake_irq(struct device *dev, int irq)
return 0;
}

+static inline int dev_pm_set_dedicated_wake_irq_reverse(struct device *dev, int irq)
+{
+ return 0;
+}
+
static inline void dev_pm_clear_wake_irq(struct device *dev)
{
}
--
2.18.0
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