[PATCH] usb: dwc3: Fix the USB 3.0 hub detection bug after warm boot

[gustavo panizzo <gfa@zumbi.com.ar>]

The dwc3 could not release resources when the module is built-in
because this module does not have shutdown method. This causes the USB
3.0 hub is not able to detect after warm boot.

Original patch by Brian Kim, updated and submitted upstream by gustavo
panizzo.

Also see https://bugs.debian.org/843448

Signed-off-by: Brian Kim <brian.kim@hardkernel.com>
Signed-off-by: gustavo panizzo <gfa@zumbi.com.ar>
---
 drivers/usb/dwc3/core.c | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 326b302fc440..f92dfe213d89 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -1259,6 +1259,38 @@ static int dwc3_probe(struct platform_device *pdev)
 	return ret;
 }
 
+static void dwc3_shutdown(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
+	 * memory region the next time probe is called.
+	 */
+	res->start -= DWC3_GLOBALS_REGS_START;
+
+	dwc3_debugfs_exit(dwc);
+	dwc3_core_exit_mode(dwc);
+	dwc3_event_buffers_cleanup(dwc);
+	dwc3_free_event_buffers(dwc);
+
+	usb_phy_set_suspend(dwc->usb2_phy, 1);
+	usb_phy_set_suspend(dwc->usb3_phy, 1);
+
+	phy_power_off(dwc->usb2_generic_phy);
+	phy_power_off(dwc->usb3_generic_phy);
+
+	dwc3_core_exit(dwc);
+	dwc3_ulpi_exit(dwc);
+
+	pm_runtime_put_sync(&pdev->dev);
+	pm_runtime_allow(&pdev->dev);
+	pm_runtime_disable(&pdev->dev);
+}
+
 static int dwc3_remove(struct platform_device *pdev)
 {
 	struct dwc3	*dwc = platform_get_drvdata(pdev);
@@ -1488,6 +1520,7 @@ MODULE_DEVICE_TABLE(acpi, dwc3_acpi_match);
 static struct platform_driver dwc3_driver = {
 	.probe		= dwc3_probe,
 	.remove		= dwc3_remove,
+	.shutdown	= dwc3_shutdown,
 	.driver		= {
 		.name	= "dwc3",
 		.of_match_table	= of_match_ptr(of_dwc3_match),
-- 
2.11.0