PM / Domains: Introduce "always on" device flag
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>
Cc: stable@vger.kernel.org
diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 84f4bee..b6ff6ec 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -366,7 +366,7 @@
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 @@
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;
@@ -859,7 +862,7 @@
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;
@@ -892,7 +895,7 @@
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;
@@ -1012,7 +1015,8 @@
if (IS_ERR(genpd))
return -EINVAL;
- return genpd->suspend_power_off ? 0 : genpd_stop_dev(genpd, dev);
+ return genpd->suspend_power_off || dev_gpd_data(dev)->always_on ?
+ 0 : genpd_stop_dev(genpd, dev);
}
/**
@@ -1032,7 +1036,8 @@
if (IS_ERR(genpd))
return -EINVAL;
- return genpd->suspend_power_off ? 0 : genpd_start_dev(genpd, dev);
+ return genpd->suspend_power_off || dev_gpd_data(dev)->always_on ?
+ 0 : genpd_start_dev(genpd, dev);
}
/**
@@ -1124,7 +1129,7 @@
pm_genpd_poweron(genpd);
- return genpd_start_dev(genpd, dev);
+ return dev_gpd_data(dev)->always_on ? 0 : genpd_start_dev(genpd, dev);
}
/**
@@ -1320,6 +1325,26 @@
}
/**
+ * 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.
* @subdomain: Subdomain to be added.
diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index 5c2bbc2..1236d26 100644
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h
@@ -99,6 +99,7 @@
struct gpd_dev_ops ops;
struct gpd_timing_data td;
bool need_restore;
+ bool always_on;
};
#ifdef CONFIG_PM_GENERIC_DOMAINS
@@ -137,6 +138,7 @@
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,
@@ -179,6 +181,7 @@
{
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)
{