usb: dwc3: implement runtime PM

this patch implements the most basic pm_runtime
support for dwc3. Whenever USB cable is dettached,
then we will allow core to runtime_suspend.

Runtime suspending will involve completely tearing
down event buffers and require a full soft-reset of
the IP.

Note that a further optimization could be
implemented once we decide to support hibernation,
which is to allow runtime_suspend with cable
connected when bus is in U3. That's subject to a
separate patch, however.

Tested-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

1 files changed, 134 insertions, 14 deletions

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 80e9affd3d77..bf1789f134ac 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -48,7 +48,7 @@
 
 #include "debug.h"
 
-/* -------------------------------------------------------------------------- */
+#define DWC3_DEFAULT_AUTOSUSPEND_DELAY	5000 /* ms */
 
 void dwc3_set_mode(struct dwc3 *dwc, u32 mode)
 {
@@ -996,6 +996,9 @@ static int dwc3_probe(struct platform_device *pdev)
 		dma_set_coherent_mask(dev, dev->parent->coherent_dma_mask);
 	}
 
+	pm_runtime_set_active(dev);
+	pm_runtime_use_autosuspend(dev);
+	pm_runtime_set_autosuspend_delay(dev, DWC3_DEFAULT_AUTOSUSPEND_DELAY);
 	pm_runtime_enable(dev);
 	pm_runtime_get_sync(dev);
 	pm_runtime_forbid(dev);
@@ -1057,7 +1060,7 @@ static int dwc3_probe(struct platform_device *pdev)
 		goto err3;
 
 	dwc3_debugfs_init(dwc);
-	pm_runtime_allow(dev);
+	pm_runtime_put(dev);
 
 	return 0;
 
@@ -1087,6 +1090,7 @@ static int dwc3_remove(struct platform_device *pdev)
 	struct dwc3	*dwc = platform_get_drvdata(pdev);
 	struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 
+	pm_runtime_get_sync(&pdev->dev);
 	/*
 	 * restore res->start back to its original value so that, in case the
 	 * probe is deferred, we don't end up getting error in request the
@@ -1100,24 +1104,27 @@ static int dwc3_remove(struct platform_device *pdev)
 	dwc3_core_exit(dwc);
 	dwc3_ulpi_exit(dwc);
 
-	dwc3_free_event_buffers(dwc);
-	dwc3_free_scratch_buffers(dwc);
-
 	pm_runtime_put_sync(&pdev->dev);
+	pm_runtime_allow(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
 
+	dwc3_free_event_buffers(dwc);
+	dwc3_free_scratch_buffers(dwc);
+
 	return 0;
 }
 
-#ifdef CONFIG_PM_SLEEP
-static int dwc3_suspend(struct device *dev)
+#ifdef CONFIG_PM
+static int dwc3_suspend_common(struct dwc3 *dwc)
 {
-	struct dwc3	*dwc = dev_get_drvdata(dev);
+	unsigned long	flags;
 
 	switch (dwc->dr_mode) {
 	case USB_DR_MODE_PERIPHERAL:
 	case USB_DR_MODE_OTG:
+		spin_lock_irqsave(&dwc->lock, flags);
 		dwc3_gadget_suspend(dwc);
+		spin_unlock_irqrestore(&dwc->lock, flags);
 		break;
 	case USB_DR_MODE_HOST:
 	default:
@@ -1127,18 +1134,14 @@ static int dwc3_suspend(struct device *dev)
 
 	dwc3_core_exit(dwc);
 
-	pinctrl_pm_select_sleep_state(dev);
-
 	return 0;
 }
 
-static int dwc3_resume(struct device *dev)
+static int dwc3_resume_common(struct dwc3 *dwc)
 {
-	struct dwc3	*dwc = dev_get_drvdata(dev);
+	unsigned long	flags;
 	int		ret;
 
-	pinctrl_pm_select_default_state(dev);
-
 	ret = dwc3_core_init(dwc);
 	if (ret)
 		return ret;
@@ -1146,7 +1149,9 @@ static int dwc3_resume(struct device *dev)
 	switch (dwc->dr_mode) {
 	case USB_DR_MODE_PERIPHERAL:
 	case USB_DR_MODE_OTG:
+		spin_lock_irqsave(&dwc->lock, flags);
 		dwc3_gadget_resume(dwc);
+		spin_unlock_irqrestore(&dwc->lock, flags);
 		/* FALLTHROUGH */
 	case USB_DR_MODE_HOST:
 	default:
@@ -1154,6 +1159,119 @@ static int dwc3_resume(struct device *dev)
 		break;
 	}
 
+	return 0;
+}
+
+static int dwc3_runtime_checks(struct dwc3 *dwc)
+{
+	switch (dwc->dr_mode) {
+	case USB_DR_MODE_PERIPHERAL:
+	case USB_DR_MODE_OTG:
+		if (dwc->connected)
+			return -EBUSY;
+		break;
+	case USB_DR_MODE_HOST:
+	default:
+		/* do nothing */
+		break;
+	}
+
+	return 0;
+}
+
+static int dwc3_runtime_suspend(struct device *dev)
+{
+	struct dwc3     *dwc = dev_get_drvdata(dev);
+	int		ret;
+
+	if (dwc3_runtime_checks(dwc))
+		return -EBUSY;
+
+	ret = dwc3_suspend_common(dwc);
+	if (ret)
+		return ret;
+
+	device_init_wakeup(dev, true);
+
+	return 0;
+}
+
+static int dwc3_runtime_resume(struct device *dev)
+{
+	struct dwc3     *dwc = dev_get_drvdata(dev);
+	int		ret;
+
+	device_init_wakeup(dev, false);
+
+	ret = dwc3_resume_common(dwc);
+	if (ret)
+		return ret;
+
+	switch (dwc->dr_mode) {
+	case USB_DR_MODE_PERIPHERAL:
+	case USB_DR_MODE_OTG:
+		dwc3_gadget_process_pending_events(dwc);
+		break;
+	case USB_DR_MODE_HOST:
+	default:
+		/* do nothing */
+		break;
+	}
+
+	pm_runtime_mark_last_busy(dev);
+
+	return 0;
+}
+
+static int dwc3_runtime_idle(struct device *dev)
+{
+	struct dwc3     *dwc = dev_get_drvdata(dev);
+
+	switch (dwc->dr_mode) {
+	case USB_DR_MODE_PERIPHERAL:
+	case USB_DR_MODE_OTG:
+		if (dwc3_runtime_checks(dwc))
+			return -EBUSY;
+		break;
+	case USB_DR_MODE_HOST:
+	default:
+		/* do nothing */
+		break;
+	}
+
+	pm_runtime_mark_last_busy(dev);
+	pm_runtime_autosuspend(dev);
+
+	return 0;
+}
+#endif /* CONFIG_PM */
+
+#ifdef CONFIG_PM_SLEEP
+static int dwc3_suspend(struct device *dev)
+{
+	struct dwc3	*dwc = dev_get_drvdata(dev);
+	int		ret;
+
+	ret = dwc3_suspend_common(dwc);
+	if (ret)
+		return ret;
+
+	pinctrl_pm_select_sleep_state(dev);
+
+	return 0;
+}
+
+static int dwc3_resume(struct device *dev)
+{
+	struct dwc3	*dwc = dev_get_drvdata(dev);
+	int		ret;
+
+	pinctrl_pm_select_default_state(dev);
+
+	ret = dwc3_resume_common(dwc);
+	if (ret)
+		return ret;
+
 	pm_runtime_disable(dev);
 	pm_runtime_set_active(dev);
 	pm_runtime_enable(dev);
@@ -1164,6 +1282,8 @@ static int dwc3_resume(struct device *dev)
 
 static const struct dev_pm_ops dwc3_dev_pm_ops = {
 	SET_SYSTEM_SLEEP_PM_OPS(dwc3_suspend, dwc3_resume)
+	SET_RUNTIME_PM_OPS(dwc3_runtime_suspend, dwc3_runtime_resume,
+			dwc3_runtime_idle)
 };
 
 #ifdef CONFIG_OF