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

["Singh, Sandeep" <ssingh1@amd.com>]

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@amd.com>
>>
>> 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@amd.com>
>> Signed-off-by: Sandeep Singh <sandeep.singh@amd.com>
>> ---
>>   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