Messages in this thread | | | Subject | Re: [PATCH v2] xhci: Add quirk to workaround the errata seen on Cavium Thunder-X2 Soc | From | Mathias Nyman <> | Date | Tue, 30 Oct 2018 11:50:08 +0200 |
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On 29.10.2018 18:54, Cherian, George wrote: > Implement workaround for ThunderX2 Errata-129 (documented in > CN99XX Known Issues" available at Cavium support site). > As per ThunderX2errata-129, USB 2 device may come up as USB 1 > if a connection to a USB 1 device is followed by another connection to > a USB 2 device, the link will come up as USB 1 for the USB 2 device. > > Resolution: Reset the PHY after the USB 1 device is disconnected. > The PHY reset sequence is done using private registers in XHCI register > space. After the PHY is reset we check for the PLL lock status and retry > the operation if it fails. From our tests, retrying 4 times is sufficient. > > Add a new quirk flag XHCI_RESET_PLL_ON_DISCONNECT to invoke the workaround > in handle_xhci_port_status(). > > Signed-off-by: George Cherian <george.cherian@cavium.com> > --- > drivers/usb/host/xhci-pci.c | 5 +++++ > drivers/usb/host/xhci-ring.c | 35 ++++++++++++++++++++++++++++++++++- > drivers/usb/host/xhci.h | 1 + > 3 files changed, 40 insertions(+), 1 deletion(-) > > diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c > index 51dd8e0..334c009 100644 > --- a/drivers/usb/host/xhci-pci.c > +++ b/drivers/usb/host/xhci-pci.c > @@ -231,6 +231,11 @@ static void xhci_pci_quirks(struct device *dev, struct xhci_hcd *xhci) > if (pdev->vendor == PCI_VENDOR_ID_TI && pdev->device == 0x8241) > xhci->quirks |= XHCI_LIMIT_ENDPOINT_INTERVAL_7; > > + if ((pdev->vendor == PCI_VENDOR_ID_BROADCOM || > + pdev->vendor == PCI_VENDOR_ID_CAVIUM) && > + pdev->device == 0x9026) > + xhci->quirks |= XHCI_RESET_PLL_ON_DISCONNECT; > + > if (xhci->quirks & XHCI_RESET_ON_RESUME) > xhci_dbg_trace(xhci, trace_xhci_dbg_quirks, > "QUIRK: Resetting on resume"); > diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c > index f0a99aa..342dd5ac 100644 > --- a/drivers/usb/host/xhci-ring.c > +++ b/drivers/usb/host/xhci-ring.c > @@ -1517,6 +1517,35 @@ static void handle_device_notification(struct xhci_hcd *xhci, > usb_wakeup_notification(udev->parent, udev->portnum); > } > > +/* > + * Quirk hanlder for errata seen on Cavium ThunderX2 processor XHCI > + * Controller. > + * As per ThunderX2errata-129 USB 2 device may come up as USB 1 > + * If a connection to a USB 1 device is followed by another connection > + * to a USB 2 device. > + * > + * Reset the PHY after the USB device is disconnected if device speed > + * is less than HCD_USB3. > + * Retry the reset sequence max of 4 times checking the PLL lock status. > + * > + */ > +static void xhci_handle_tx2_wrapper_reset(struct xhci_hcd *xhci)
Maybe rename this to make it more obvious it's about a quirk. xhci_cavium_reset_phy_quirk() maybe?
> +{ > + struct usb_hcd *hcd = xhci_to_hcd(xhci); > + u32 pll_lock_check; > + u32 retry_count = 4; > + > + do { > + /* Assert PHY reset */ > + writel(0x6F, hcd->regs + 0x1048); > + udelay(10); > + /* De-assert the PHY reset */ > + writel(0x7F, hcd->regs + 0x1048); > + udelay(200); > + pll_lock_check = readl(hcd->regs + 0x1070); > + } while (!(pll_lock_check & 0x1) && --retry_count); > +} > + > static void handle_port_status(struct xhci_hcd *xhci, > union xhci_trb *event) > { > @@ -1642,8 +1671,12 @@ static void handle_port_status(struct xhci_hcd *xhci, > goto cleanup; > } > > - if (hcd->speed < HCD_USB3) > + if (hcd->speed < HCD_USB3) { > xhci_test_and_clear_bit(xhci, port, PORT_PLC); > + if ((portsc & PORT_CSC) && !(portsc & 0x1) && > + (xhci->quirks & XHCI_RESET_PLL_ON_DISCONNECT)) > + xhci_handle_tx2_wrapper_reset(xhci); > + }
Check for the quirk first, this way I can ignore the rest of the code when debugging other issues, and use PORT_CONNECT instead of 0x1
something like:
if ((xhci->quirks & XHCI_RESET_PLL_ON_DISCONNECT) && (portsc & PORT_CSC) && !(portsc & PORT_CONNECT))
Thanks -Mathias
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