[PATCH V3] xhci: Reset TI USB controller on xhci shutdown

[wenxiong]

From: Wen Xiong <wenxiong@xxxxxxxxxxxxx>

Fixes kexec boot. Without a hard reset, TI pci usb chips will fail to
initialize in a kexec booted kernel.

Signed-off-by: Wen Xiong <wenxiong@xxxxxxxxxxxxx>
---
 drivers/usb/host/xhci-pci.c | 4 +++-
 drivers/usb/host/xhci.c     | 8 ++++++++
 drivers/usb/host/xhci.h     | 1 +
 3 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index a8889081ae82..782178da4057 100644
--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -479,8 +479,10 @@ static void xhci_pci_quirks(struct device *dev, struct xhci_hcd *xhci)
 	    pdev->device == PCI_DEVICE_ID_ASMEDIA_3042_XHCI)
 		xhci->quirks |= XHCI_RESET_ON_RESUME;
 
-	if (pdev->vendor == PCI_VENDOR_ID_TI && pdev->device == 0x8241)
+	if (pdev->vendor == PCI_VENDOR_ID_TI && pdev->device == 0x8241) {
 		xhci->quirks |= XHCI_LIMIT_ENDPOINT_INTERVAL_7;
+		xhci->quirks |= XHCI_RESET_ON_SHUTDOWN;
+	}
 
 	if ((pdev->vendor == PCI_VENDOR_ID_BROADCOM ||
 	     pdev->vendor == PCI_VENDOR_ID_CAVIUM) &&
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index a9e47e178c28..8e5e25ebb6b5 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -750,6 +750,7 @@ EXPORT_SYMBOL_GPL(xhci_stop);
 void xhci_shutdown(struct usb_hcd *hcd)
 {
 	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
+	int err;
 
 	if (xhci->quirks & XHCI_SPURIOUS_REBOOT)
 		usb_disable_xhci_ports(to_pci_dev(hcd->self.sysdev));
@@ -781,6 +782,13 @@ void xhci_shutdown(struct usb_hcd *hcd)
 	xhci_dbg_trace(xhci, trace_xhci_dbg_init,
 			"xhci_shutdown completed - status = %x",
 			readl(&xhci->op_regs->status));
+
+	/*
+	 * TI xHCI controllers fail to initialize in a kexec
+	 * kernel without a PCI function reset
+	 */
+	if (err && (xhci->quirks & XHCI_RESET_ON_SHUTDOWN))
+		pci_reset_function_locked(to_pci_dev(hcd->self.sysdev));
 }
 EXPORT_SYMBOL_GPL(xhci_shutdown);
 
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index c7bfa7f028d3..e94a38e5f4ac 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1647,6 +1647,7 @@ struct xhci_hcd {
 #define XHCI_CDNS_SCTX_QUIRK	BIT_ULL(48)
 #define XHCI_ETRON_HOST	BIT_ULL(49)
 #define XHCI_LIMIT_ENDPOINT_INTERVAL_9 BIT_ULL(50)
+#define XHCI_RESET_ON_SHUTDOWN	BIT_ULL(51)
 
 	unsigned int		num_active_eps;
 	unsigned int		limit_active_eps;
-- 
2.52.0