linux-kernel - [PATCH v10 1/5] PM / Runtime: Allow accessing irq_safe if no PM

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Date:	Thu, 06 Nov 2014 09:36:46 +0100
From:	Krzysztof Kozlowski <k.kozlowski@...sung.com>
To:	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Len Brown <len.brown@...el.com>, Pavel Machek <pavel@....cz>,
	Russell King <linux@....linux.org.uk>,
	Dan Williams <dan.j.williams@...el.com>,
	Vinod Koul <vinod.koul@...el.com>,
	Ulf Hansson <ulf.hansson@...aro.org>,
	Alan Stern <stern@...land.harvard.edu>,
	linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
	dmaengine@...r.kernel.org, Lars-Peter Clausen <lars@...afoo.de>,
	Michal Simek <michal.simek@...inx.com>
Cc:	Kevin Hilman <khilman@...nel.org>,
	Laurent Pinchart <laurent.pinchart@...asonboard.com>,
	Kyungmin Park <kyungmin.park@...sung.com>,
	Marek Szyprowski <m.szyprowski@...sung.com>,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
	Krzysztof Kozlowski <k.kozlowski@...sung.com>
Subject: [PATCH v10 1/5] PM / Runtime: Allow accessing irq_safe if no PM_RUNTIME

Some drivers (e.g. bus drivers) may want to check if power.irq_safe was
called by child driver, regardless of CONFIG_PM_RUNTIME.

An example scenario is amba/bus.c and dma/pl330.c drivers. The runtime
suspend/resume callbacks in amba bus driver act differently if irq_safe
was set by child driver (in irq_safe mode bus clock is only disabled).

The pl330 driver sets irq_safe and assumes that amba bus driver will
only disable the clock in runtime PM. So in system sleep suspend
callback the pl330 driver unprepares the clock after calling
pm_runtime_force_suspend().

However inconsistency would appear if CONFIG_PM_RUNTIME is not set and
child drivers do not want the irq_safe runtime PM. In such case amba bus
driver still has to know whether child driver wanted irq_safe - by
looking at dev->power.irq_safe field.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@...sung.com>
---
 include/linux/pm.h         | 2 +-
 include/linux/pm_runtime.h | 5 ++++-
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/include/linux/pm.h b/include/linux/pm.h
index 383fd68aaee1..b05fa954f50d 100644
--- a/include/linux/pm.h
+++ b/include/linux/pm.h
@@ -566,6 +566,7 @@ struct dev_pm_info {
 	bool			ignore_children:1;
 	bool			early_init:1;	/* Owned by the PM core */
 	bool			direct_complete:1;	/* Owned by the PM core */
+	unsigned int		irq_safe:1;	/* PM runtime */
 	spinlock_t		lock;
 #ifdef CONFIG_PM_SLEEP
 	struct list_head	entry;
@@ -590,7 +591,6 @@ struct dev_pm_info {
 	unsigned int		run_wake:1;
 	unsigned int		runtime_auto:1;
 	unsigned int		no_callbacks:1;
-	unsigned int		irq_safe:1;
 	unsigned int		use_autosuspend:1;
 	unsigned int		timer_autosuspends:1;
 	unsigned int		memalloc_noio:1;
diff --git a/include/linux/pm_runtime.h b/include/linux/pm_runtime.h
index 367f49b9a1c9..d94a65662a60 100644
--- a/include/linux/pm_runtime.h
+++ b/include/linux/pm_runtime.h
@@ -166,7 +166,10 @@ static inline bool pm_runtime_suspended_if_enabled(struct device *dev) { return
 static inline bool pm_runtime_enabled(struct device *dev) { return false; }
 
 static inline void pm_runtime_no_callbacks(struct device *dev) {}
-static inline void pm_runtime_irq_safe(struct device *dev) {}
+static inline void pm_runtime_irq_safe(struct device *dev)
+{
+	dev->power.irq_safe = 1;
+}
 
 static inline bool pm_runtime_callbacks_present(struct device *dev) { return false; }
 static inline void pm_runtime_mark_last_busy(struct device *dev) {}
-- 
1.9.1

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