PM: sleep: Add strict_midlayer flag to struct dev_pm_info

Add a new flag, called strict_midlayer, to struct dev_pm_info, along
with helper functions for updating and reading its value, to allow
middle layer code that provides proper callbacks for device suspend-
resume during system-wide PM transitions to let pm_runtime_force_suspend()
and and pm_runtime_force_resume() know that they should only invoke
runtime PM callbacks coming from the device's driver.

Namely, if this flag is set, pm_runtime_force_suspend() and
and pm_runtime_force_resume() will invoke runtime PM callbacks
provided by the device's driver directly with the assumption that
they have been called via a middle layer callback for device suspend
or resume, respectively.

For instance, acpi_general_pm_domain provides specific
callback functions for system suspend, acpi_subsys_suspend(),
acpi_subsys_suspend_late() and acpi_subsys_suspend_noirq(), and
it does not expect its runtime suspend callback function,
acpi_subsys_runtime_suspend(), to be invoked at any point during
system suspend. In particular, it does not expect that function
to be called from within any of the system suspend callback functions
mentioned above which would happen if a device driver collaborating
with acpi_general_pm_domain used pm_runtime_force_suspend() as its
callback function for any system suspend phase later than "prepare".

The new flag allows this expectation of acpi_general_pm_domain to
be formally expressed, which is going to be done subsequently.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://patch.msgid.link/24017035.6Emhk5qWAg@rjwysocki.net

1 files changed, 27 insertions, 0 deletions

diff --git a/include/linux/device.h b/include/linux/device.h
index 4940db137fff..5137f9d213ec 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -879,6 +879,33 @@ static inline bool dev_pm_smart_suspend(struct device *dev)
 #endif
 }
 
+/*
+ * dev_pm_set_strict_midlayer - Update the device's power.strict_midlayer flag
+ * @dev: Target device.
+ * @val: New flag value.
+ *
+ * When set, power.strict_midlayer means that the middle layer power management
+ * code (typically, a bus type or a PM domain) does not expect its runtime PM
+ * suspend callback to be invoked at all during system-wide PM transitions and
+ * it does not expect its runtime PM resume callback to be invoked at any point
+ * when runtime PM is disabled for the device during system-wide PM transitions.
+ */
+static inline void dev_pm_set_strict_midlayer(struct device *dev, bool val)
+{
+#ifdef CONFIG_PM_SLEEP
+	dev->power.strict_midlayer = val;
+#endif
+}
+
+static inline bool dev_pm_strict_midlayer_is_set(struct device *dev)
+{
+#ifdef CONFIG_PM_SLEEP
+	return dev->power.strict_midlayer;
+#else
+	return false;
+#endif
+}
+
 static inline void device_lock(struct device *dev)
 {
 	mutex_lock(&dev->mutex);