Patrick Georgi has submitted this change. ( https://review.coreboot.org/c/coreboot/+/44876 )
Change subject: xhci: Do not set the CRCR_CS bit ......................................................................
xhci: Do not set the CRCR_CS bit
We do not need to set the CS (Command Stop) bit in the Command Ring Control Register. CS is implied by CA (Command Abort). I'm not sure if there is a defined execution order for these command bits, so it's safer to only use the CA bit as it includes the CS function.
Ref: xHCI spec 1.2 (May 2019), Section 5.4.5, Table 5-24.
BUG=b:160354585,b:157123390 TEST=able to boot into recovery using USB stick on servo v2 on volteer as well as HooToo 8-1 hub
Change-Id: Iaeba98b6da8da49f529358ca6d68270440ea0f42 Signed-off-by: Caveh Jalali caveh@chromium.org Reviewed-on: https://review.coreboot.org/c/coreboot/+/44876 Tested-by: build bot (Jenkins) no-reply@coreboot.org Reviewed-by: Julius Werner jwerner@chromium.org --- M payloads/libpayload/drivers/usb/xhci_commands.c 1 file changed, 7 insertions(+), 1 deletion(-)
Approvals: build bot (Jenkins): Verified Julius Werner: Looks good to me, approved
diff --git a/payloads/libpayload/drivers/usb/xhci_commands.c b/payloads/libpayload/drivers/usb/xhci_commands.c index d633cc5..a407803 100644 --- a/payloads/libpayload/drivers/usb/xhci_commands.c +++ b/payloads/libpayload/drivers/usb/xhci_commands.c @@ -75,7 +75,13 @@ /* Abort command on timeout */ xhci_debug("Aborting command (@%p), CRCR: 0x%"PRIx32"\n", cmd_trb, xhci->opreg->crcr_lo); - xhci->opreg->crcr_lo |= CRCR_CS | CRCR_CA; + /* + * Ref. xHCI Specification Revision 1.2, May 2019. + * Section 5.4.5, Table 5-24. + * + * Abort the command and stop the ring. + */ + xhci->opreg->crcr_lo |= CRCR_CA; xhci->opreg->crcr_hi = 0; cc = xhci_wait_for_command_aborted(xhci, cmd_trb);