New patch to review for coreboot: bdd7d2a libpayload: xhci: Ensure to reset dequeue pointer on stopped endpoints

[Isaac Christensen]

Isaac Christensen ([e-mail]) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/6787

-gerrit

commit bdd7d2a6269d15959e4d2ddf0701bf5763b07a5a
Author: Julius Werner 
Date:   Thu Sep 26 15:13:44 2013 -0700

libpayload: xhci: Ensure to reset dequeue pointer on stopped endpoints

This patch fixes a bug in the XHCI stack that occurs when a multi-TRB TD
    times out before the last TRB is processed. The driver will correctly
    issue a Stop Endpoint command in that case, but the xHC will still
    preserve the transfer state and just pick up right after that on the
    next doorbell ring. It will then process the leftover TRBs from the old
    TD the next time a transfer is issued. (cf. XHCI 4.6.9)

We fix this by changing the existing xhci_reset_endpoint() calls in
    transfer functions to not only trigger on Halted (2) and Error (4), but
    also on Stopped (3). That function will not actually issue a Reset
    Endpoint command in this case, but it will nuke the whole transfer ring
    and issue a Set TR Dequeue Pointer command, which is sufficient (though
    slightly overkill) to solve our problem.

Change-Id: I3abbe30ff9d4911a8af1f792324e018d427019e8
    Signed-off-by: Julius Werner 
    Reviewed-on: https://chromium-review.googlesource.com/170833
    Reviewed-by: Ronald Minnich 
    Reviewed-by: Kees Cook 
    (cherry picked from commit f12424af0e29ac12963e8e5a7970fadcc0bb6cee)
    Signed-off-by: Isaac Christensen 
---
 payloads/libpayload/drivers/usb/xhci.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/payloads/libpayload/drivers/usb/xhci.c b/payloads/libpayload/drivers/usb/xhci.c
index 4ab2fe3..5b30d0c 100644
--- a/payloads/libpayload/drivers/usb/xhci.c
+++ b/payloads/libpayload/drivers/usb/xhci.c
@@ -599,9 +599,9 @@ xhci_control(usbdev_t *const dev, const direction_t dir,
    	return -1;
    }

-	/* Reset endpoint if it's halted */
+	/* Reset endpoint if it's not running */
    const unsigned ep_state = EC_GET(STATE, epctx);
-	if (ep_state == 2 || ep_state == 4) {
+	if (ep_state > 1) {
    	if (xhci_reset_endpoint(dev, NULL, 0))
    		return -1;
    }
@@ -710,9 +710,9 @@ xhci_bulk(endpoint_t *const ep, const int size, u8 *const src,
    		memcpy(data, src, size);
    }

-	/* Reset endpoint if it's halted */
+	/* Reset endpoint if it's not running */
    const unsigned ep_state = EC_GET(STATE, epctx);
-	if (ep_state == 2 || ep_state == 4) {
+	if (ep_state > 1) {
    	if (xhci_reset_endpoint(ep->dev, ep, 0))
    		return -1;
    }