usb: xhci: tegra: Add shutdown callback for Tegra XUSB

If memory accesses by the Tegra XUSB controller are translated through
the SMMU (System MMU), the hardware may continue accessing memory even
after the SMMU translations have been disabled during the shutdown
process and this can in turn cause unpredictable crashes.
Fix this by adding a shutdown implementation that ensures the hardware
is turned off during system reboot or shutdown.
Signed-off-by: Henry Lin <henryl@nvidia.com>
Signed-off-by: Haotien Hsu <haotienh@nvidia.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Link: https://lore.kernel.org/r/20230727074927.2428611-1-haotienh@nvidia.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/xhci-tegra.c

@@ -1912,6 +1912,15 @@ static int tegra_xusb_probe(struct platform_device *pdev)
 	return err;
 }
 
+static void tegra_xusb_disable(struct tegra_xusb *tegra)
+{
+	tegra_xusb_powergate_partitions(tegra);
+	tegra_xusb_powerdomain_remove(tegra->dev, tegra);
+	tegra_xusb_phy_disable(tegra);
+	tegra_xusb_clk_disable(tegra);
+	regulator_bulk_disable(tegra->soc->num_supplies, tegra->supplies);
+}
+
 static void tegra_xusb_remove(struct platform_device *pdev)
 {
 	struct tegra_xusb *tegra = platform_get_drvdata(pdev);
@@ -1934,14 +1943,18 @@ static void tegra_xusb_remove(struct platform_device *pdev)
 
 	pm_runtime_put(&pdev->dev);
 
-	tegra_xusb_powergate_partitions(tegra);
+	tegra_xusb_disable(tegra);
+	tegra_xusb_padctl_put(tegra->padctl);
+}
 
-	tegra_xusb_powerdomain_remove(&pdev->dev, tegra);
+static void tegra_xusb_shutdown(struct platform_device *pdev)
+{
+	struct tegra_xusb *tegra = platform_get_drvdata(pdev);
 
-	tegra_xusb_phy_disable(tegra);
-	tegra_xusb_clk_disable(tegra);
-	regulator_bulk_disable(tegra->soc->num_supplies, tegra->supplies);
-	tegra_xusb_padctl_put(tegra->padctl);
+	pm_runtime_get_sync(&pdev->dev);
+	disable_irq(tegra->xhci_irq);
+	xhci_shutdown(tegra->hcd);
+	tegra_xusb_disable(tegra);
 }
 
 static bool xhci_hub_ports_suspended(struct xhci_hub *hub)
@@ -2652,6 +2665,7 @@ MODULE_DEVICE_TABLE(of, tegra_xusb_of_match);
 static struct platform_driver tegra_xusb_driver = {
 	.probe = tegra_xusb_probe,
 	.remove_new = tegra_xusb_remove,
+	.shutdown = tegra_xusb_shutdown,
 	.driver = {
 		.name = "tegra-xusb",
 		.pm = &tegra_xusb_pm_ops,