PM / Runtime: Rework the "runtime idle" helper routine

The "runtime idle" helper routine, rpm_idle(), currently ignores
return values from .runtime_idle() callbacks executed by it.
However, it turns out that many subsystems use
pm_generic_runtime_idle() which checks the return value of the
driver's callback and executes pm_runtime_suspend() for the device
unless that value is not 0. If that logic is moved to rpm_idle()
instead, pm_generic_runtime_idle() can be dropped and its users
will not need any .runtime_idle() callbacks any more.

Moreover, the PCI, SCSI, and SATA subsystems' .runtime_idle()
routines, pci_pm_runtime_idle(), scsi_runtime_idle(), and
ata_port_runtime_idle(), respectively, as well as a few drivers'
ones may be simplified if rpm_idle() calls rpm_suspend() after 0 has
been returned by the .runtime_idle() callback executed by it.

To reduce overall code bloat, make the changes described above.

Tested-by: Mika Westerberg <[e-mail]>
Tested-by: Kevin Hilman <[e-mail]>
Signed-off-by: Rafael J. Wysocki <[e-mail]>
Acked-by: Kevin Hilman <[e-mail]>
Reviewed-by: Ulf Hansson <[e-mail]>
Acked-by: Alan Stern <[e-mail]>

Documentation/power/runtime_pm.txt

···
 management callbacks provided by the PM core, defined in
 driver/base/power/generic_ops.c:
 
-  int pm_generic_runtime_idle(struct device *dev);
-    - invoke the ->runtime_idle() callback provided by the driver of this
-      device, if defined, and call pm_runtime_suspend() for this device if the
-      return value is 0 or the callback is not defined
-
   int pm_generic_runtime_suspend(struct device *dev);
     - invoke the ->runtime_suspend() callback provided by the driver of this
       device and return its result, or return -EINVAL if not defined

arch/arm/mach-omap2/omap_device.c

···
 	return ret;
 }
 
-static int _od_runtime_idle(struct device *dev)
-{
-	return pm_generic_runtime_idle(dev);
-}
-
 static int _od_runtime_resume(struct device *dev)
 {
 	struct platform_device *pdev = to_platform_device(dev);
···
 struct dev_pm_domain omap_device_pm_domain = {
 	.ops = {
 		SET_RUNTIME_PM_OPS(_od_runtime_suspend, _od_runtime_resume,
-				   _od_runtime_idle)
+				   NULL)
 		USE_PLATFORM_PM_SLEEP_OPS
 		.suspend_noirq = _od_suspend_noirq,
 		.resume_noirq = _od_resume_noirq,

drivers/acpi/device_pm.c

···
 #ifdef CONFIG_PM_RUNTIME
 		.runtime_suspend = acpi_subsys_runtime_suspend,
 		.runtime_resume = acpi_subsys_runtime_resume,
-		.runtime_idle = pm_generic_runtime_idle,
 #endif
 #ifdef CONFIG_PM_SLEEP
 		.prepare = acpi_subsys_prepare,

drivers/amba/bus.c

···
 	SET_RUNTIME_PM_OPS(
 		amba_pm_runtime_suspend,
 		amba_pm_runtime_resume,
-		pm_generic_runtime_idle
+		NULL
 	)
 };
 

drivers/ata/libata-core.c

···
 				return -EBUSY;
 	}
 
-	return pm_runtime_suspend(dev);
+	return 0;
 }
 
 static int ata_port_runtime_suspend(struct device *dev)

drivers/base/platform.c

···
 static const struct dev_pm_ops platform_dev_pm_ops = {
 	.runtime_suspend = pm_generic_runtime_suspend,
 	.runtime_resume = pm_generic_runtime_resume,
-	.runtime_idle = pm_generic_runtime_idle,
 	USE_PLATFORM_PM_SLEEP_OPS
 };
 

drivers/base/power/domain.c

···
 	genpd->max_off_time_changed = true;
 	genpd->domain.ops.runtime_suspend = pm_genpd_runtime_suspend;
 	genpd->domain.ops.runtime_resume = pm_genpd_runtime_resume;
-	genpd->domain.ops.runtime_idle = pm_generic_runtime_idle;
 	genpd->domain.ops.prepare = pm_genpd_prepare;
 	genpd->domain.ops.suspend = pm_genpd_suspend;
 	genpd->domain.ops.suspend_late = pm_genpd_suspend_late;

drivers/base/power/generic_ops.c

···
 
 #ifdef CONFIG_PM_RUNTIME
 /**
- * pm_generic_runtime_idle - Generic runtime idle callback for subsystems.
- * @dev: Device to handle.
- *
- * If PM operations are defined for the @dev's driver and they include
- * ->runtime_idle(), execute it and return its error code, if nonzero.
- * Otherwise, execute pm_runtime_suspend() for the device and return 0.
- */
-int pm_generic_runtime_idle(struct device *dev)
-{
-	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
-
-	if (pm && pm->runtime_idle) {
-		int ret = pm->runtime_idle(dev);
-		if (ret)
-			return ret;
-	}
-
-	pm_runtime_suspend(dev);
-	return 0;
-}
-EXPORT_SYMBOL_GPL(pm_generic_runtime_idle);
-
-/**
  * pm_generic_runtime_suspend - Generic runtime suspend callback for subsystems.
  * @dev: Device to suspend.
  *

drivers/base/power/runtime.c

···
 	/* Pending requests need to be canceled. */
 	dev->power.request = RPM_REQ_NONE;
 
-	if (dev->power.no_callbacks) {
-		/* Assume ->runtime_idle() callback would have suspended. */
-		retval = rpm_suspend(dev, rpmflags);
+	if (dev->power.no_callbacks)
 		goto out;
-	}
 
 	/* Carry out an asynchronous or a synchronous idle notification. */
 	if (rpmflags & RPM_ASYNC) {
···
 			dev->power.request_pending = true;
 			queue_work(pm_wq, &dev->power.work);
 		}
-		goto out;
+		trace_rpm_return_int(dev, _THIS_IP_, 0);
+		return 0;
 	}
 
 	dev->power.idle_notification = true;
···
 		callback = dev->driver->pm->runtime_idle;
 
 	if (callback)
-		__rpm_callback(callback, dev);
+		retval = __rpm_callback(callback, dev);
 
 	dev->power.idle_notification = false;
 	wake_up_all(&dev->power.wait_queue);
 
  out:
 	trace_rpm_return_int(dev, _THIS_IP_, retval);
-	return retval;
+	return retval ? retval : rpm_suspend(dev, rpmflags);
 }
 
 /**

drivers/dma/intel_mid_dma.c

···
 			return -EAGAIN;
 	}
 
-	return pm_schedule_suspend(dev, 0);
+	return 0;
 }
 
 /******************************************************************************

drivers/gpio/gpio-langwell.c

···
 
 static int lnw_gpio_runtime_idle(struct device *dev)
 {
-	int err = pm_schedule_suspend(dev, 500);
-
-	if (!err)
-		return 0;
-
+	pm_schedule_suspend(dev, 500);
 	return -EBUSY;
 }
 

drivers/i2c/i2c-core.c

···
 	SET_RUNTIME_PM_OPS(
 		pm_generic_runtime_suspend,
 		pm_generic_runtime_resume,
-		pm_generic_runtime_idle
+		NULL
 	)
 };
 

drivers/mfd/ab8500-gpadc.c

···
 	return ret;
 }
 
-static int ab8500_gpadc_runtime_idle(struct device *dev)
-{
-	pm_runtime_suspend(dev);
-	return 0;
-}
-
 static int ab8500_gpadc_suspend(struct device *dev)
 {
 	struct ab8500_gpadc *gpadc = dev_get_drvdata(dev);
···
 static const struct dev_pm_ops ab8500_gpadc_pm_ops = {
 	SET_RUNTIME_PM_OPS(ab8500_gpadc_runtime_suspend,
 			   ab8500_gpadc_runtime_resume,
-			   ab8500_gpadc_runtime_idle)
+			   NULL)
 	SET_SYSTEM_SLEEP_PM_OPS(ab8500_gpadc_suspend,
 				ab8500_gpadc_resume)
 

drivers/mmc/core/bus.c

···
 
 static int mmc_runtime_idle(struct device *dev)
 {
-	return pm_runtime_suspend(dev);
+	return 0;
 }
 
 #endif /* !CONFIG_PM_RUNTIME */

drivers/mmc/core/sdio_bus.c

···
 	SET_RUNTIME_PM_OPS(
 		pm_generic_runtime_suspend,
 		pm_generic_runtime_resume,
-		pm_generic_runtime_idle
+		NULL
 	)
 };
 

drivers/pci/pci-driver.c

···
 {
 	struct pci_dev *pci_dev = to_pci_dev(dev);
 	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
+	int ret = 0;
 
 	/*
 	 * If pci_dev->driver is not set (unbound), the device should
 	 * always remain in D0 regardless of the runtime PM status
 	 */
 	if (!pci_dev->driver)
-		goto out;
+		return 0;
 
 	if (!pm)
 		return -ENOSYS;
 
-	if (pm->runtime_idle) {
-		int ret = pm->runtime_idle(dev);
-		if (ret)
-			return ret;
-	}
+	if (pm->runtime_idle)
+		ret = pm->runtime_idle(dev);
 
-out:
-	pm_runtime_suspend(dev);
-	return 0;
+	return ret;
 }
 
 #else /* !CONFIG_PM_RUNTIME */

drivers/scsi/scsi_pm.c

···
 
 static int scsi_runtime_idle(struct device *dev)
 {
-	int err;
-
 	dev_dbg(dev, "scsi_runtime_idle\n");
 
 	/* Insert hooks here for targets, hosts, and transport classes */
···
 
 		if (sdev->request_queue->dev) {
 			pm_runtime_mark_last_busy(dev);
-			err = pm_runtime_autosuspend(dev);
-		} else {
-			err = pm_runtime_suspend(dev);
+			pm_runtime_autosuspend(dev);
+			return -EBUSY;
 		}
-	} else {
-		err = pm_runtime_suspend(dev);
 	}
-	return err;
+	return 0;
 }
 
 int scsi_autopm_get_device(struct scsi_device *sdev)

drivers/sh/pm_runtime.c

···
 static int default_platform_runtime_idle(struct device *dev)
 {
 	/* suspend synchronously to disable clocks immediately */
-	return pm_runtime_suspend(dev);
+	return 0;
 }
 
 static struct dev_pm_domain default_pm_domain = {

drivers/spi/spi.c

···
 	SET_RUNTIME_PM_OPS(
 		pm_generic_runtime_suspend,
 		pm_generic_runtime_resume,
-		pm_generic_runtime_idle
+		NULL
 	)
 };
 

drivers/tty/serial/mfd.c

···
 #ifdef CONFIG_PM_RUNTIME
 static int serial_hsu_runtime_idle(struct device *dev)
 {
-	int err;
-
-	err = pm_schedule_suspend(dev, 500);
-	if (err)
-		return -EBUSY;
-
-	return 0;
+	pm_schedule_suspend(dev, 500);
+	return -EBUSY;
 }
 
 static int serial_hsu_runtime_suspend(struct device *dev)

drivers/usb/core/driver.c

···
 	 */
 	if (autosuspend_check(udev) == 0)
 		pm_runtime_autosuspend(dev);
-	return 0;
+	/* Tell the core not to suspend it, though. */
+	return -EBUSY;
 }
 
 int usb_set_usb2_hardware_lpm(struct usb_device *udev, int enable)

drivers/usb/core/port.c

···
 #ifdef CONFIG_PM_RUNTIME
 	.runtime_suspend =	usb_port_runtime_suspend,
 	.runtime_resume =	usb_port_runtime_resume,
-	.runtime_idle =		pm_generic_runtime_idle,
 #endif
 };
 

include/linux/pm_runtime.h

···
 extern void __pm_runtime_disable(struct device *dev, bool check_resume);
 extern void pm_runtime_allow(struct device *dev);
 extern void pm_runtime_forbid(struct device *dev);
-extern int pm_generic_runtime_idle(struct device *dev);
 extern int pm_generic_runtime_suspend(struct device *dev);
 extern int pm_generic_runtime_resume(struct device *dev);
 extern void pm_runtime_no_callbacks(struct device *dev);
···
 static inline bool pm_runtime_status_suspended(struct device *dev) { return false; }
 static inline bool pm_runtime_enabled(struct device *dev) { return false; }
 
-static inline int pm_generic_runtime_idle(struct device *dev) { return 0; }
 static inline int pm_generic_runtime_suspend(struct device *dev) { return 0; }
 static inline int pm_generic_runtime_resume(struct device *dev) { return 0; }
 static inline void pm_runtime_no_callbacks(struct device *dev) {}