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

From: Singh, Sandeep
Date: Fri Oct 23 2020 - 08:41:15 EST


Hi Greg,

On 10/23/2020 6:03 PM, Greg KH wrote:
[CAUTION: External Email]

On Fri, Oct 23, 2020 at 05:57:13PM +0530, Sandeep Singh wrote:
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

Does this build? There is no XHCI_DISABLE_SPARSE in the kernel tree at
the moment...

 Sorry i missed adding xhci.h in this patch i will be sending v2 patch.

greg k-h

Thanks

Sandeep