[PATCH] xhci: tegra: Fix ghost USB device on dual-role port unplug

[PATCH] xhci: tegra: Fix ghost USB device on dual-role port unplug

[Wei-Cheng Chen]

When a USB device is unplugged from the dual-role port, the device-mode
path in tegra_xhci_id_work() explicitly clears both SS and HS port power
via direct hub_control ClearPortFeature(POWER) calls. This preempts the
xHCI controller's normal disconnect processing -- PORT_CSC is never
generated, the USB core never sees the disconnect, and the device remains
in its internal tree as a ghost visible in lsusb.

Add an otg_set_port_power flag to control whether the dual-role switch
path performs explicit port power management. SoCs that need it
(Tegra124 / Tegra210 / Tegra186) set the flag; later SoCs (Tegra194 and
beyond) rely on the PHY mode change to handle disconnect naturally and
skip all port power calls.

Within the port power path, otg_reset_sspi additionally gates the SSPI
reset sequence on host-mode entry for SoCs that require it.

Flags set per SoC:
  Tegra124, Tegra186  -> otg_set_port_power
  Tegra210            -> otg_set_port_power, otg_reset_sspi
  Tegra194 and later  -> (none)

Fixes: f836e7843036 ("usb: xhci-tegra: Add OTG support")
Cc: stable@vger.kernel.org # v5.7+
Signed-off-by: Wei-Cheng Chen <weichengc@nvidia.com>
---
 drivers/usb/host/xhci-tegra.c | 73 ++++++++++++++++++++---------------
 1 file changed, 41 insertions(+), 32 deletions(-)

diff --git a/drivers/usb/host/xhci-tegra.c b/drivers/usb/host/xhci-tegra.c
index d2214d309e9..d5637b37636 100644
--- a/drivers/usb/host/xhci-tegra.c
+++ b/drivers/usb/host/xhci-tegra.c
@@ -247,6 +247,7 @@ struct tegra_xusb_soc {
 	bool has_ipfs;
 	bool lpm_support;
 	bool otg_reset_sspi;
+	bool otg_set_port_power;
 
 	bool has_bar2;
 };
@@ -1352,12 +1353,13 @@ static void tegra_xhci_id_work(struct work_struct *work)
 	struct tegra_xusb_mbox_msg msg;
 	struct phy *phy = tegra_xusb_get_phy(tegra, "usb2",
 						    tegra->otg_usb2_port);
+	bool host_mode = tegra->host_mode;
 	u32 status;
 	int ret;
 
-	dev_dbg(tegra->dev, "host mode %s\n", str_on_off(tegra->host_mode));
+	dev_dbg(tegra->dev, "host mode %s\n", str_on_off(host_mode));
 
-	if (tegra->host_mode)
+	if (host_mode)
 		phy_set_mode_ext(phy, PHY_MODE_USB_OTG, USB_ROLE_HOST);
 	else
 		phy_set_mode_ext(phy, PHY_MODE_USB_OTG, USB_ROLE_NONE);
@@ -1366,41 +1368,43 @@ static void tegra_xhci_id_work(struct work_struct *work)
 								    tegra->otg_usb2_port);
 
 	pm_runtime_get_sync(tegra->dev);
-	if (tegra->host_mode) {
-		/* switch to host mode */
-		if (tegra->otg_usb3_port >= 0) {
-			if (tegra->soc->otg_reset_sspi) {
-				/* set PP=0 */
-				tegra_xhci_hc_driver.hub_control(
-					xhci->shared_hcd, GetPortStatus,
-					0, tegra->otg_usb3_port+1,
-					(char *) &status, sizeof(status));
-				if (status & USB_SS_PORT_STAT_POWER)
-					tegra_xhci_set_port_power(tegra, false,
-								  false);
-
-				/* reset OTG port SSPI */
-				msg.cmd = MBOX_CMD_RESET_SSPI;
-				msg.data = tegra->otg_usb3_port+1;
-
-				ret = tegra_xusb_mbox_send(tegra, &msg);
-				if (ret < 0) {
-					dev_info(tegra->dev,
-						"failed to RESET_SSPI %d\n",
-						ret);
+	if (tegra->soc->otg_set_port_power) {
+		if (host_mode) {
+			/* switch to host mode */
+			if (tegra->otg_usb3_port >= 0) {
+				if (tegra->soc->otg_reset_sspi) {
+					/* set PP=0 */
+					tegra_xhci_hc_driver.hub_control(
+						xhci->shared_hcd, GetPortStatus,
+						0, tegra->otg_usb3_port+1,
+						(char *) &status, sizeof(status));
+					if (status & USB_SS_PORT_STAT_POWER)
+						tegra_xhci_set_port_power(tegra, false,
+									  false);
+
+					/* reset OTG port SSPI */
+					msg.cmd = MBOX_CMD_RESET_SSPI;
+					msg.data = tegra->otg_usb3_port+1;
+
+					ret = tegra_xusb_mbox_send(tegra, &msg);
+					if (ret < 0) {
+						dev_info(tegra->dev,
+							"failed to RESET_SSPI %d\n",
+							ret);
+					}
 				}
-			}
 
-			tegra_xhci_set_port_power(tegra, false, true);
-		}
+				tegra_xhci_set_port_power(tegra, false, true);
+			}
 
-		tegra_xhci_set_port_power(tegra, true, true);
+			tegra_xhci_set_port_power(tegra, true, true);
 
-	} else {
-		if (tegra->otg_usb3_port >= 0)
-			tegra_xhci_set_port_power(tegra, false, false);
+		} else {
+			if (tegra->otg_usb3_port >= 0)
+				tegra_xhci_set_port_power(tegra, false, false);
 
-		tegra_xhci_set_port_power(tegra, true, false);
+			tegra_xhci_set_port_power(tegra, true, false);
+		}
 	}
 	pm_runtime_put_autosuspend(tegra->dev);
 }
@@ -2553,6 +2557,7 @@ static const struct tegra_xusb_soc tegra124_soc = {
 	.scale_ss_clock = true,
 	.has_ipfs = true,
 	.otg_reset_sspi = false,
+	.otg_set_port_power = true,
 	.ops = &tegra124_ops,
 	.mbox = {
 		.cmd = 0xe4,
@@ -2593,6 +2598,7 @@ static const struct tegra_xusb_soc tegra210_soc = {
 	.scale_ss_clock = false,
 	.has_ipfs = true,
 	.otg_reset_sspi = true,
+	.otg_set_port_power = true,
 	.ops = &tegra124_ops,
 	.mbox = {
 		.cmd = 0xe4,
@@ -2640,6 +2646,7 @@ static const struct tegra_xusb_soc tegra186_soc = {
 	.scale_ss_clock = false,
 	.has_ipfs = false,
 	.otg_reset_sspi = false,
+	.otg_set_port_power = true,
 	.ops = &tegra124_ops,
 	.mbox = {
 		.cmd = 0xe4,
@@ -2673,6 +2680,7 @@ static const struct tegra_xusb_soc tegra194_soc = {
 	.scale_ss_clock = false,
 	.has_ipfs = false,
 	.otg_reset_sspi = false,
+	.otg_set_port_power = false,
 	.ops = &tegra124_ops,
 	.mbox = {
 		.cmd = 0x68,
@@ -2708,6 +2716,7 @@ static const struct tegra_xusb_soc tegra234_soc = {
 	.scale_ss_clock = false,
 	.has_ipfs = false,
 	.otg_reset_sspi = false,
+	.otg_set_port_power = false,
 	.ops = &tegra234_ops,
 	.mbox = {
 		.cmd = XUSB_BAR2_ARU_MBOX_CMD,
-- 
2.43.0