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authorNicolas Pitre <npitre@baylibre.com>2021-01-25 22:29:18 +0300
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2021-01-27 21:29:32 +0300
commit0bfa0820c274b019583b3454c6c889c99c24558d (patch)
tree8d899f423a9cd330f987d7c894c50335b58116f5 /include/linux/pm.h
parent6ee1d745b7c9fd573fba142a2efdad76a9f1cb04 (diff)
downloadlinux-0bfa0820c274b019583b3454c6c889c99c24558d.tar.xz
PM: clk: make PM clock layer compatible with clocks that must sleep
The clock API splits its interface into sleepable ant atomic contexts: - clk_prepare/clk_unprepare for stuff that might sleep - clk_enable_clk_disable for anything that may be done in atomic context The code handling runtime PM for clocks only calls clk_disable() on suspend requests, and clk_enable on resume requests. This means that runtime PM with clock providers that only have the prepare/unprepare methods implemented is basically useless. Many clock implementations can't accommodate atomic contexts. This is often the case when communication with the clock happens through another subsystem like I2C or SCMI. Let's make the clock PM code useful with such clocks by safely invoking clk_prepare/clk_unprepare upon resume/suspend requests. Of course, when such clocks are registered with the PM layer then pm_runtime_irq_safe() can't be used, and neither pm_runtime_suspend() nor pm_runtime_resume() may be invoked in atomic context. For clocks that do implement the enable and disable methods then everything just works as before. A note on sparse: According to https://lwn.net/Articles/109066/ there are things that sparse can't cope with. In particular, pm_clk_op_lock() and pm_clk_op_unlock() may or may not lock/unlock psd->lock depending on some runtime condition. To work around that we tell it the lock is always untaken for the purpose of static analisys. Thanks to Naresh Kamboju for reporting issues with the initial patch. Signed-off-by: Nicolas Pitre <npitre@baylibre.com> Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'include/linux/pm.h')
-rw-r--r--include/linux/pm.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/pm.h b/include/linux/pm.h
index 47aca6bac1d6..482313a8ccfc 100644
--- a/include/linux/pm.h
+++ b/include/linux/pm.h
@@ -537,6 +537,8 @@ struct pm_subsys_data {
spinlock_t lock;
unsigned int refcount;
#ifdef CONFIG_PM_CLK
+ unsigned int clock_op_might_sleep;
+ struct mutex clock_mutex;
struct list_head clock_list;
#endif
#ifdef CONFIG_PM_GENERIC_DOMAINS