[PATCH] usb: xhci: Workaround for S3 issue on AMD SNPS 3.0 xHC

[Sandeep Singh]

From: Sandeep Singh <sandeep.singh@xxxxxxx>

On some platform of AMD, S3 fails with HCE and SRE errors. To fix this,
need to disable a bit which is enable in sparse controller.

Signed-off-by: Sanket Goswami <Sanket.Goswami@xxxxxxx>
Signed-off-by: Sandeep Singh <sandeep.singh@xxxxxxx>
---
 drivers/usb/host/xhci-pci.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index c26c06e5c88c..bf89172c43ca 100644
--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -23,6 +23,8 @@
 #define SSIC_PORT_CFG2_OFFSET	0x30
 #define PROG_DONE		(1 << 30)
 #define SSIC_PORT_UNUSED	(1 << 31)
+#define SPARSE_DISABLE_BIT	17
+#define SPARSE_CNTL_ENABLE	0xC12C
 
 /* Device for a quirk */
 #define PCI_VENDOR_ID_FRESCO_LOGIC	0x1b73
@@ -161,6 +163,9 @@ static void xhci_pci_quirks(struct device *dev, struct xhci_hcd *xhci)
 	    (pdev->device == 0x15e0 || pdev->device == 0x15e1))
 		xhci->quirks |= XHCI_SNPS_BROKEN_SUSPEND;
 
+	if (pdev->vendor == PCI_VENDOR_ID_AMD && pdev->device == 0x15e5)
+		xhci->quirks |= XHCI_DISABLE_SPARSE;
+
 	if (pdev->vendor == PCI_VENDOR_ID_AMD)
 		xhci->quirks |= XHCI_TRUST_TX_LENGTH;
 
@@ -498,6 +503,15 @@ static void xhci_pme_quirk(struct usb_hcd *hcd)
 	readl(reg);
 }
 
+static void xhci_sparse_control_quirk(struct usb_hcd *hcd)
+{
+	u32 reg;
+
+	reg = readl(hcd->regs + SPARSE_CNTL_ENABLE);
+	reg &= ~BIT(SPARSE_DISABLE_BIT);
+	writel(reg, hcd->regs + SPARSE_CNTL_ENABLE);
+}
+
 static int xhci_pci_suspend(struct usb_hcd *hcd, bool do_wakeup)
 {
 	struct xhci_hcd	*xhci = hcd_to_xhci(hcd);
@@ -517,6 +531,9 @@ static int xhci_pci_suspend(struct usb_hcd *hcd, bool do_wakeup)
 	if (xhci->quirks & XHCI_SSIC_PORT_UNUSED)
 		xhci_ssic_port_unused_quirk(hcd, true);
 
+	if (xhci->quirks & XHCI_DISABLE_SPARSE)
+		xhci_sparse_control_quirk(hcd);
+
 	ret = xhci_suspend(xhci, do_wakeup);
 	if (ret && (xhci->quirks & XHCI_SSIC_PORT_UNUSED))
 		xhci_ssic_port_unused_quirk(hcd, false);
-- 
2.25.1