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authorAndiry Xu <andiry.xu@amd.com>2012-03-05 17:49:34 +0800
committerSarah Sharp <sarah.a.sharp@linux.intel.com>2012-03-13 09:29:55 -0700
commitb008df60c6369ba0290fa7daa177375407a12e07 (patch)
tree05a59c4a4d8d624b18ad0844949841f36b241c17 /drivers/usb/host/xhci.c
parent3fe4fe083d3355537565b2b0a678807513dfa013 (diff)
xHCI: count free TRBs on transfer ring
In the past, the room_on_ring() check was implemented by walking all over the ring, which is wasteful and complicated. Count the number of free TRBs instead. The free TRBs number should be updated when enqueue/dequeue pointer is updated, or upon the completion of a set dequeue pointer command. Signed-off-by: Andiry Xu <andiry.xu@amd.com> Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> Tested-by: Paul Zimmerman <Paul.Zimmerman@synopsys.com>
Diffstat (limited to 'drivers/usb/host/xhci.c')
-rw-r--r--drivers/usb/host/xhci.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 262400c10075..dec5b2dc298c 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -729,6 +729,7 @@ static void xhci_clear_command_ring(struct xhci_hcd *xhci)
ring->enq_seg = ring->deq_seg;
ring->enqueue = ring->dequeue;
+ ring->num_trbs_free = ring->num_segs * (TRBS_PER_SEGMENT - 1) - 1;
/*
* Ring is now zeroed, so the HW should look for change of ownership
* when the cycle bit is set to 1.