diff options
Diffstat (limited to 'payloads/libpayload/drivers')
| -rw-r--r-- | payloads/libpayload/drivers/usb/xhci.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/payloads/libpayload/drivers/usb/xhci.c b/payloads/libpayload/drivers/usb/xhci.c index 71272c7133..d223d0f190 100644 --- a/payloads/libpayload/drivers/usb/xhci.c +++ b/payloads/libpayload/drivers/usb/xhci.c @@ -328,6 +328,17 @@ xhci_reset(hci_t *const controller) xhci_stop(controller); xhci->opreg->usbcmd |= USBCMD_HCRST; + + /* Existing Intel xHCI controllers require a delay of 1 ms, + * after setting the CMD_RESET bit, and before accessing any + * HC registers. This allows the HC to complete the + * reset operation and be ready for HC register access. + * Without this delay, the subsequent HC register access, + * may result in a system hang very rarely. + */ + if (IS_ENABLED(CONFIG_LP_ARCH_X86)) + mdelay(1); + xhci_debug("Resetting controller... "); if (!xhci_handshake(&xhci->opreg->usbcmd, USBCMD_HCRST, 0, 1000000L)) usb_debug("timeout!\n"); |