PM / Domains: Introduce "always on" device flag

This is a backport of mainline commit
1e78a0c7fc92aee076965d516cf54475c39e9894.

The TMU device on the Mackerel board belongs to the A4R power domain
and loses power when the domain is turned off.  Unfortunately, the
TMU driver is not prepared to cope with such situations and crashes
the system when that happens.  To work around this problem introduce
a new helper function, pm_genpd_dev_always_on(), allowing a device
driver to mark its device as "always on" in case it belongs to a PM
domain, which will make the generic PM domains core code avoid
powering off the domain containing the device, both at run time and
during system suspend.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Tested-by: Simon Horman <horms@verge.net.au>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 5771275f1be4a25d0220b5cb2754bc60c8e0a960..58c8b4def2f74ff6157ab7d45268a09d713333b4 100644 (file)
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -366,7 +366,7 @@ static int pm_genpd_poweroff(struct generic_pm_domain *genpd)
        not_suspended = 0;
        list_for_each_entry(pdd, &genpd->dev_list, list_node)
                if (pdd->dev->driver && (!pm_runtime_suspended(pdd->dev)
-                   || pdd->dev->power.irq_safe))
+                   || pdd->dev->power.irq_safe || to_gpd_data(pdd)->always_on))
                        not_suspended++;
 
        if (not_suspended > genpd->in_progress)
@@ -503,6 +503,9 @@ static int pm_genpd_runtime_suspend(struct device *dev)
 
        might_sleep_if(!genpd->dev_irq_safe);
 
+       if (dev_gpd_data(dev)->always_on)
+               return -EBUSY;
+
        stop_ok = genpd->gov ? genpd->gov->stop_ok : NULL;
        if (stop_ok && !stop_ok(dev))
                return -EBUSY;
@@ -847,7 +850,8 @@ static int pm_genpd_suspend_noirq(struct device *dev)
        if (ret)
                return ret;
 
-       if (dev->power.wakeup_path && genpd_dev_active_wakeup(genpd, dev))
+       if (dev_gpd_data(dev)->always_on
+           || (dev->power.wakeup_path && genpd_dev_active_wakeup(genpd, dev)))
                return 0;
 
        genpd_stop_dev(genpd, dev);
@@ -882,7 +886,7 @@ static int pm_genpd_resume_noirq(struct device *dev)
        if (IS_ERR(genpd))
                return -EINVAL;
 
-       if (genpd->suspend_power_off
+       if (genpd->suspend_power_off || dev_gpd_data(dev)->always_on
            || (dev->power.wakeup_path && genpd_dev_active_wakeup(genpd, dev)))
                return 0;
 
@@ -960,7 +964,7 @@ static int pm_genpd_freeze_noirq(struct device *dev)
        if (IS_ERR(genpd))
                return -EINVAL;
 
-       if (genpd->suspend_power_off)
+       if (genpd->suspend_power_off || dev_gpd_data(dev)->always_on)
                return 0;
 
        ret = genpd_freeze_late(genpd, dev);
@@ -991,7 +995,7 @@ static int pm_genpd_thaw_noirq(struct device *dev)
        if (IS_ERR(genpd))
                return -EINVAL;
 
-       if (genpd->suspend_power_off)
+       if (genpd->suspend_power_off || dev_gpd_data(dev)->always_on)
                return 0;
 
        genpd_start_dev(genpd, dev);
@@ -1064,7 +1068,7 @@ static int pm_genpd_restore_noirq(struct device *dev)
                }
        }
 
-       if (genpd->suspend_power_off)
+       if (genpd->suspend_power_off || dev_gpd_data(dev)->always_on)
                return 0;
 
        pm_genpd_poweron(genpd);
@@ -1229,6 +1233,26 @@ int pm_genpd_remove_device(struct generic_pm_domain *genpd,
        return ret;
 }
 
+/**
+ * pm_genpd_dev_always_on - Set/unset the "always on" flag for a given device.
+ * @dev: Device to set/unset the flag for.
+ * @val: The new value of the device's "always on" flag.
+ */
+void pm_genpd_dev_always_on(struct device *dev, bool val)
+{
+       struct pm_subsys_data *psd;
+       unsigned long flags;
+
+       spin_lock_irqsave(&dev->power.lock, flags);
+
+       psd = dev_to_psd(dev);
+       if (psd && psd->domain_data)
+               to_gpd_data(psd->domain_data)->always_on = val;
+
+       spin_unlock_irqrestore(&dev->power.lock, flags);
+}
+EXPORT_SYMBOL_GPL(pm_genpd_dev_always_on);
+
 /**
  * pm_genpd_add_subdomain - Add a subdomain to an I/O PM domain.
  * @genpd: Master PM domain to add the subdomain to.

diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index a03a0ad998b81498b26697927931606d0349e13d..5a82c0908bf38d85a029b19b934ad9e4643a6e98 100644 (file)
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h
@@ -97,6 +97,7 @@ struct generic_pm_domain_data {
        struct gpd_dev_ops ops;
        struct gpd_timing_data td;
        bool need_restore;
+       bool always_on;
 };
 
 static inline struct generic_pm_domain_data *to_gpd_data(struct pm_domain_data *pdd)
@@ -125,6 +126,7 @@ static inline int pm_genpd_add_device(struct generic_pm_domain *genpd,
 
 extern int pm_genpd_remove_device(struct generic_pm_domain *genpd,
                                  struct device *dev);
+extern void pm_genpd_dev_always_on(struct device *dev, bool val);
 extern int pm_genpd_add_subdomain(struct generic_pm_domain *genpd,
                                  struct generic_pm_domain *new_subdomain);
 extern int pm_genpd_remove_subdomain(struct generic_pm_domain *genpd,
@@ -163,6 +165,7 @@ static inline int pm_genpd_remove_device(struct generic_pm_domain *genpd,
 {
        return -ENOSYS;
 }
+static inline void pm_genpd_dev_always_on(struct device *dev, bool val) {}
 static inline int pm_genpd_add_subdomain(struct generic_pm_domain *genpd,
                                         struct generic_pm_domain *new_sd)
 {