From 6c12db90f19727c76990e7f4801c67a148b30111 Mon Sep 17 00:00:00 2001 From: John Youn Date: Mon, 10 May 2010 15:33:00 -0700 Subject: [PATCH] USB: xhci: Transfer ring link TRB activation change. Change transfer ring behavior to not follow/activate link TRBs until active TRBs are queued after it. This change affects the behavior when a TD ends just before a link TRB. Signed-off-by: John Youn Signed-off-by: Sarah Sharp Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/xhci-ring.c | 71 +++++++++++++++++++++++++++++------- 1 file changed, 58 insertions(+), 13 deletions(-) diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c index 15f02e88f329..803f6810e996 100644 --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -112,6 +112,12 @@ static inline int last_trb(struct xhci_hcd *xhci, struct xhci_ring *ring, return (trb->link.control & TRB_TYPE_BITMASK) == TRB_TYPE(TRB_LINK); } +static inline int enqueue_is_link_trb(struct xhci_ring *ring) +{ + struct xhci_link_trb *link = &ring->enqueue->link; + return ((link->control & TRB_TYPE_BITMASK) == TRB_TYPE(TRB_LINK)); +} + /* Updates trb to point to the next TRB in the ring, and updates seg if the next * TRB is in a new segment. This does not skip over link TRBs, and it does not * effect the ring dequeue or enqueue pointers. @@ -193,20 +199,15 @@ static void inc_enq(struct xhci_hcd *xhci, struct xhci_ring *ring, bool consumer while (last_trb(xhci, ring, ring->enq_seg, next)) { if (!consumer) { if (ring != xhci->event_ring) { - /* If we're not dealing with 0.95 hardware, - * carry over the chain bit of the previous TRB - * (which may mean the chain bit is cleared). - */ - if (!xhci_link_trb_quirk(xhci)) { - next->link.control &= ~TRB_CHAIN; - next->link.control |= chain; + if (chain) { + next->link.control |= TRB_CHAIN; + + /* Give this link TRB to the hardware */ + wmb(); + next->link.control ^= TRB_CYCLE; + } else { + break; } - /* Give this link TRB to the hardware */ - wmb(); - if (next->link.control & TRB_CYCLE) - next->link.control &= (u32) ~TRB_CYCLE; - else - next->link.control |= (u32) TRB_CYCLE; } /* Toggle the cycle bit after the last ring segment. */ if (last_trb_on_last_seg(xhci, ring, ring->enq_seg, next)) { @@ -245,6 +246,13 @@ static int room_on_ring(struct xhci_hcd *xhci, struct xhci_ring *ring, struct xhci_segment *cur_seg; unsigned int left_on_ring; + /* If we are currently pointing to a link TRB, advance the + * enqueue pointer before checking for space */ + while (last_trb(xhci, ring, enq_seg, enq)) { + enq_seg = enq_seg->next; + enq = enq_seg->trbs; + } + /* Check if ring is empty */ if (enq == ring->dequeue) { /* Can't use link trbs */ @@ -1728,6 +1736,43 @@ static int prepare_ring(struct xhci_hcd *xhci, struct xhci_ring *ep_ring, xhci_err(xhci, "ERROR no room on ep ring\n"); return -ENOMEM; } + + if (enqueue_is_link_trb(ep_ring)) { + struct xhci_ring *ring = ep_ring; + union xhci_trb *next; + unsigned long long addr; + + xhci_dbg(xhci, "prepare_ring: pointing to link trb\n"); + next = ring->enqueue; + + while (last_trb(xhci, ring, ring->enq_seg, next)) { + + /* If we're not dealing with 0.95 hardware, + * clear the chain bit. + */ + if (!xhci_link_trb_quirk(xhci)) + next->link.control &= ~TRB_CHAIN; + else + next->link.control |= TRB_CHAIN; + + wmb(); + next->link.control ^= (u32) TRB_CYCLE; + + /* Toggle the cycle bit after the last ring segment. */ + if (last_trb_on_last_seg(xhci, ring, ring->enq_seg, next)) { + ring->cycle_state = (ring->cycle_state ? 0 : 1); + if (!in_interrupt()) { + xhci_dbg(xhci, "queue_trb: Toggle cycle " + "state for ring %p = %i\n", + ring, (unsigned int)ring->cycle_state); + } + } + ring->enq_seg = ring->enq_seg->next; + ring->enqueue = ring->enq_seg->trbs; + next = ring->enqueue; + } + } + return 0; } -- 2.30.2