Merge branch 'pm-qos'

* pm-qos:
sh_mmcif / PM: Use PM QoS latency constraint
tmio_mmc / PM: Use PM QoS latency constraint
PM / QoS: Make it possible to expose PM QoS latency constraints

Documentation/ABI/testing/sysfs-devices-power

···
 
 		Not all drivers support this attribute.  If it isn't supported,
 		attempts to read or write it will yield I/O errors.
+
+What:		/sys/devices/.../power/pm_qos_latency_us
+Date:		March 2012
+Contact:	Rafael J. Wysocki <[e-mail]>
+Description:
+		The /sys/devices/.../power/pm_qos_resume_latency_us attribute
+		contains the PM QoS resume latency limit for the given device,
+		which is the maximum allowed time it can take to resume the
+		device, after it has been suspended at run time, from a resume
+		request to the moment the device will be ready to process I/O,
+		in microseconds.  If it is equal to 0, however, this means that
+		the PM QoS resume latency may be arbitrary.
+
+		Not all drivers support this attribute.  If it isn't supported,
+		it is not present.
+
+		This attribute has no effect on system-wide suspend/resume and
+		hibernation.

drivers/base/power/power.h

···
 extern void rpm_sysfs_remove(struct device *dev);
 extern int wakeup_sysfs_add(struct device *dev);
 extern void wakeup_sysfs_remove(struct device *dev);
+extern int pm_qos_sysfs_add(struct device *dev);
+extern void pm_qos_sysfs_remove(struct device *dev);
 
 #else /* CONFIG_PM */
 
···
 static inline void rpm_sysfs_remove(struct device *dev) {}
 static inline int wakeup_sysfs_add(struct device *dev) { return 0; }
 static inline void wakeup_sysfs_remove(struct device *dev) {}
+static inline int pm_qos_sysfs_add(struct device *dev) { return 0; }
+static inline void pm_qos_sysfs_remove(struct device *dev) {}
 
 #endif

drivers/base/power/qos.c

···
 #include <linux/mutex.h>
 #include <linux/export.h>
 
+#include "power.h"
 
 static DEFINE_MUTEX(dev_pm_qos_mtx);
 
···
 {
 	struct dev_pm_qos_request *req, *tmp;
 	struct pm_qos_constraints *c;
+
+	/*
+	 * If the device's PM QoS resume latency limit has been exposed to user
+	 * space, it has to be hidden at this point.
+	 */
+	dev_pm_qos_hide_latency_limit(dev);
 
 	mutex_lock(&dev_pm_qos_mtx);
 
···
 	return error;
 }
 EXPORT_SYMBOL_GPL(dev_pm_qos_add_ancestor_request);
+
+#ifdef CONFIG_PM_RUNTIME
+static void __dev_pm_qos_drop_user_request(struct device *dev)
+{
+	dev_pm_qos_remove_request(dev->power.pq_req);
+	dev->power.pq_req = 0;
+}
+
+/**
+ * dev_pm_qos_expose_latency_limit - Expose PM QoS latency limit to user space.
+ * @dev: Device whose PM QoS latency limit is to be exposed to user space.
+ * @value: Initial value of the latency limit.
+ */
+int dev_pm_qos_expose_latency_limit(struct device *dev, s32 value)
+{
+	struct dev_pm_qos_request *req;
+	int ret;
+
+	if (!device_is_registered(dev) || value < 0)
+		return -EINVAL;
+
+	if (dev->power.pq_req)
+		return -EEXIST;
+
+	req = kzalloc(sizeof(*req), GFP_KERNEL);
+	if (!req)
+		return -ENOMEM;
+
+	ret = dev_pm_qos_add_request(dev, req, value);
+	if (ret < 0)
+		return ret;
+
+	dev->power.pq_req = req;
+	ret = pm_qos_sysfs_add(dev);
+	if (ret)
+		__dev_pm_qos_drop_user_request(dev);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(dev_pm_qos_expose_latency_limit);
+
+/**
+ * dev_pm_qos_hide_latency_limit - Hide PM QoS latency limit from user space.
+ * @dev: Device whose PM QoS latency limit is to be hidden from user space.
+ */
+void dev_pm_qos_hide_latency_limit(struct device *dev)
+{
+	if (dev->power.pq_req) {
+		pm_qos_sysfs_remove(dev);
+		__dev_pm_qos_drop_user_request(dev);
+	}
+}
+EXPORT_SYMBOL_GPL(dev_pm_qos_hide_latency_limit);
+#endif /* CONFIG_PM_RUNTIME */

drivers/base/power/sysfs.c

···
 #include <linux/device.h>
 #include <linux/string.h>
 #include <linux/export.h>
+#include <linux/pm_qos.h>
 #include <linux/pm_runtime.h>
 #include <linux/atomic.h>
 #include <linux/jiffies.h>
···
 static DEVICE_ATTR(autosuspend_delay_ms, 0644, autosuspend_delay_ms_show,
 		autosuspend_delay_ms_store);
 
+static ssize_t pm_qos_latency_show(struct device *dev,
+				   struct device_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%d\n", dev->power.pq_req->node.prio);
+}
+
+static ssize_t pm_qos_latency_store(struct device *dev,
+				    struct device_attribute *attr,
+				    const char *buf, size_t n)
+{
+	s32 value;
+	int ret;
+
+	if (kstrtos32(buf, 0, &value))
+		return -EINVAL;
+
+	if (value < 0)
+		return -EINVAL;
+
+	ret = dev_pm_qos_update_request(dev->power.pq_req, value);
+	return ret < 0 ? ret : n;
+}
+
+static DEVICE_ATTR(pm_qos_resume_latency_us, 0644,
+		   pm_qos_latency_show, pm_qos_latency_store);
 #endif /* CONFIG_PM_RUNTIME */
 
 #ifdef CONFIG_PM_SLEEP
···
 	.attrs	= runtime_attrs,
 };
 
+static struct attribute *pm_qos_attrs[] = {
+#ifdef CONFIG_PM_RUNTIME
+	&dev_attr_pm_qos_resume_latency_us.attr,
+#endif /* CONFIG_PM_RUNTIME */
+	NULL,
+};
+static struct attribute_group pm_qos_attr_group = {
+	.name	= power_group_name,
+	.attrs	= pm_qos_attrs,
+};
+
 int dpm_sysfs_add(struct device *dev)
 {
 	int rc;
···
 void wakeup_sysfs_remove(struct device *dev)
 {
 	sysfs_unmerge_group(&dev->kobj, &pm_wakeup_attr_group);
+}
+
+int pm_qos_sysfs_add(struct device *dev)
+{
+	return sysfs_merge_group(&dev->kobj, &pm_qos_attr_group);
+}
+
+void pm_qos_sysfs_remove(struct device *dev)
+{
+	sysfs_unmerge_group(&dev->kobj, &pm_qos_attr_group);
 }
 
 void rpm_sysfs_remove(struct device *dev)

drivers/mmc/host/sh_mmcif.c

···
 #include <linux/mmc/sh_mmcif.h>
 #include <linux/pagemap.h>
 #include <linux/platform_device.h>
+#include <linux/pm_qos.h>
 #include <linux/pm_runtime.h>
 #include <linux/spinlock.h>
 #include <linux/module.h>
···
 	if (ret < 0)
 		goto clean_up5;
 
+	dev_pm_qos_expose_latency_limit(&pdev->dev, 100);
+
 	dev_info(&pdev->dev, "driver version %s\n", DRIVER_VERSION);
 	dev_dbg(&pdev->dev, "chip ver H'%04x\n",
 		sh_mmcif_readl(host->addr, MMCIF_CE_VERSION) & 0x0000ffff);
···
 
 	host->dying = true;
 	pm_runtime_get_sync(&pdev->dev);
+
+	dev_pm_qos_hide_latency_limit(&pdev->dev);
 
 	mmc_remove_host(host->mmc);
 	sh_mmcif_writel(host->addr, MMCIF_CE_INT_MASK, MASK_ALL);

drivers/mmc/host/tmio_mmc_pio.c

···
 #include <linux/module.h>
 #include <linux/pagemap.h>
 #include <linux/platform_device.h>
+#include <linux/pm_qos.h>
 #include <linux/pm_runtime.h>
 #include <linux/scatterlist.h>
 #include <linux/spinlock.h>
···
 
 	mmc_add_host(mmc);
 
+	dev_pm_qos_expose_latency_limit(&pdev->dev, 100);
+
 	/* Unmask the IRQs we want to know about */
 	if (!_host->chan_rx)
 		irq_mask |= TMIO_MASK_READOP;
···
 		|| host->mmc->caps & MMC_CAP_NEEDS_POLL
 		|| host->mmc->caps & MMC_CAP_NONREMOVABLE)
 		pm_runtime_get_sync(&pdev->dev);
+
+	dev_pm_qos_hide_latency_limit(&pdev->dev);
 
 	mmc_remove_host(host->mmc);
 	cancel_work_sync(&host->done);

include/linux/pm.h

···
 	unsigned long		accounting_timestamp;
 	ktime_t			suspend_time;
 	s64			max_time_suspended_ns;
+	struct dev_pm_qos_request *pq_req;
 #endif
 	struct pm_subsys_data	*subsys_data;  /* Owned by the subsystem. */
 	struct pm_qos_constraints *constraints;

include/linux/pm_qos.h

···
 			{ return 0; }
 #endif
 
+#ifdef CONFIG_PM_RUNTIME
+int dev_pm_qos_expose_latency_limit(struct device *dev, s32 value);
+void dev_pm_qos_hide_latency_limit(struct device *dev);
+#else
+static inline int dev_pm_qos_expose_latency_limit(struct device *dev, s32 value)
+			{ return 0; }
+static inline void dev_pm_qos_hide_latency_limit(struct device *dev) {}
+#endif
+
 #endif