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| author | Mathias Nyman <mathias.nyman@linux.intel.com> | 2016-10-20 18:09:19 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-10-20 18:54:55 +0300 |
| commit | 346e99736c3ce328fd42d678343b70243aca5f36 (patch) | |
| tree | 4132b0eb2dcbd89e109c7ce5cacb8626a16220ba /drivers/usb/host/xhci-hub.c | |
| parent | 4c39135aa412d2f1381e43802523da110ca7855c (diff) | |
| download | linux-346e99736c3ce328fd42d678343b70243aca5f36.tar.xz | |
xhci: workaround for hosts missing CAS bit
If a device is unplugged and replugged during Sx system suspend
some Intel xHC hosts will overwrite the CAS (Cold attach status) flag
and no device connection is noticed in resume.
A device in this state can be identified in resume if its link state
is in polling or compliance mode, and the current connect status is 0.
A device in this state needs to be warm reset.
Intel 100/c230 series PCH specification update Doc #332692-006 Errata #8
Observed on Cherryview and Apollolake as they go into compliance mode
if LFPS times out during polling, and re-plugged devices are not
discovered at resume.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
CC: <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/host/xhci-hub.c')
| -rw-r--r-- | drivers/usb/host/xhci-hub.c | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c index 730b9fd26685..c047362b3768 100644 --- a/drivers/usb/host/xhci-hub.c +++ b/drivers/usb/host/xhci-hub.c @@ -1355,6 +1355,35 @@ int xhci_bus_suspend(struct usb_hcd *hcd) return 0; } +/* + * Workaround for missing Cold Attach Status (CAS) if device re-plugged in S3. + * warm reset a USB3 device stuck in polling or compliance mode after resume. + * See Intel 100/c230 series PCH specification update Doc #332692-006 Errata #8 + */ +static bool xhci_port_missing_cas_quirk(int port_index, + __le32 __iomem **port_array) +{ + u32 portsc; + + portsc = readl(port_array[port_index]); + + /* if any of these are set we are not stuck */ + if (portsc & (PORT_CONNECT | PORT_CAS)) + return false; + + if (((portsc & PORT_PLS_MASK) != XDEV_POLLING) && + ((portsc & PORT_PLS_MASK) != XDEV_COMP_MODE)) + return false; + + /* clear wakeup/change bits, and do a warm port reset */ + portsc &= ~(PORT_RWC_BITS | PORT_CEC | PORT_WAKE_BITS); + portsc |= PORT_WR; + writel(portsc, port_array[port_index]); + /* flush write */ + readl(port_array[port_index]); + return true; +} + int xhci_bus_resume(struct usb_hcd *hcd) { struct xhci_hcd *xhci = hcd_to_xhci(hcd); @@ -1392,6 +1421,14 @@ int xhci_bus_resume(struct usb_hcd *hcd) u32 temp; temp = readl(port_array[port_index]); + + /* warm reset CAS limited ports stuck in polling/compliance */ + if ((xhci->quirks & XHCI_MISSING_CAS) && + (hcd->speed >= HCD_USB3) && + xhci_port_missing_cas_quirk(port_index, port_array)) { + xhci_dbg(xhci, "reset stuck port %d\n", port_index); + continue; + } if (DEV_SUPERSPEED_ANY(temp)) temp &= ~(PORT_RWC_BITS | PORT_CEC | PORT_WAKE_BITS); else |