From 416b0d26b06bdb49fde51a28ffa7254cc404a9ac Mon Sep 17 00:00:00 2001 From: Mathias Nyman Date: Tue, 19 Aug 2014 15:17:58 +0300 Subject: [PATCH] xhci: rework cycle bit checking for new dequeue pointers commit 365038d83313951d6ace15342eb24624bbef1666 upstream. When we manually need to move the TR dequeue pointer we need to set the correct cycle bit as well. Previously we used the trb pointer from the last event received as a base, but this was changed in commit 1f81b6d22a59 ("usb: xhci: Prefer endpoint context dequeue pointer") to use the dequeue pointer from the endpoint context instead It turns out some Asmedia controllers advance the dequeue pointer stored in the endpoint context past the event triggering TRB, and this messed up the way the cycle bit was calculated. Instead of adding a quirk or complicating the already hard to follow cycle bit code, the whole cycle bit calculation is now simplified and adapted to handle event and endpoint context dequeue pointer differences. Fixes: 1f81b6d22a59 ("usb: xhci: Prefer endpoint context dequeue pointer") Reported-by: Maciej Puzio Reported-by: Evan Langlois Reviewed-by: Julius Werner Tested-by: Maciej Puzio Tested-by: Evan Langlois Signed-off-by: Mathias Nyman Signed-off-by: Greg Kroah-Hartman [bwh: Backported to 3.2: - Debug logging in xhci_find_new_dequeue_state() is slightly different - Don't delete find_trb_seg(); it's still needed by xhci_cmd_to_noop()] Signed-off-by: Ben Hutchings --- drivers/usb/host/xhci-ring.c | 76 +++++++++++++++++++----------------- drivers/usb/host/xhci.c | 3 ++ 2 files changed, 43 insertions(+), 36 deletions(-) diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c index fa2f7d3e92a7..4b6abb667214 100644 --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -572,9 +572,12 @@ void xhci_find_new_dequeue_state(struct xhci_hcd *xhci, struct xhci_virt_device *dev = xhci->devs[slot_id]; struct xhci_virt_ep *ep = &dev->eps[ep_index]; struct xhci_ring *ep_ring; - struct xhci_generic_trb *trb; + struct xhci_segment *new_seg; + union xhci_trb *new_deq; dma_addr_t addr; u64 hw_dequeue; + bool cycle_found = false; + bool td_last_trb_found = false; ep_ring = xhci_triad_to_transfer_ring(xhci, slot_id, ep_index, stream_id); @@ -598,44 +601,45 @@ void xhci_find_new_dequeue_state(struct xhci_hcd *xhci, hw_dequeue = le64_to_cpu(ep_ctx->deq); } - /* Find virtual address and segment of hardware dequeue pointer */ - state->new_deq_seg = ep_ring->deq_seg; - state->new_deq_ptr = ep_ring->dequeue; - while (xhci_trb_virt_to_dma(state->new_deq_seg, state->new_deq_ptr) - != (dma_addr_t)(hw_dequeue & ~0xf)) { - next_trb(xhci, ep_ring, &state->new_deq_seg, - &state->new_deq_ptr); - if (state->new_deq_ptr == ep_ring->dequeue) { - WARN_ON(1); - return; - } - } + new_seg = ep_ring->deq_seg; + new_deq = ep_ring->dequeue; + state->new_cycle_state = hw_dequeue & 0x1; + /* - * Find cycle state for last_trb, starting at old cycle state of - * hw_dequeue. If there is only one segment ring, find_trb_seg() will - * return immediately and cannot toggle the cycle state if this search - * wraps around, so add one more toggle manually in that case. + * We want to find the pointer, segment and cycle state of the new trb + * (the one after current TD's last_trb). We know the cycle state at + * hw_dequeue, so walk the ring until both hw_dequeue and last_trb are + * found. */ - state->new_cycle_state = hw_dequeue & 0x1; - if (ep_ring->first_seg == ep_ring->first_seg->next && - cur_td->last_trb < state->new_deq_ptr) - state->new_cycle_state ^= 0x1; - - state->new_deq_ptr = cur_td->last_trb; - xhci_dbg(xhci, "Finding segment containing last TRB in TD.\n"); - state->new_deq_seg = find_trb_seg(state->new_deq_seg, - state->new_deq_ptr, &state->new_cycle_state); - if (!state->new_deq_seg) { - WARN_ON(1); - return; - } + do { + if (!cycle_found && xhci_trb_virt_to_dma(new_seg, new_deq) + == (dma_addr_t)(hw_dequeue & ~0xf)) { + cycle_found = true; + if (td_last_trb_found) + break; + } + if (new_deq == cur_td->last_trb) + td_last_trb_found = true; + + if (cycle_found && + TRB_TYPE_LINK_LE32(new_deq->generic.field[3]) && + new_deq->generic.field[3] & cpu_to_le32(LINK_TOGGLE)) + state->new_cycle_state ^= 0x1; + + next_trb(xhci, ep_ring, &new_seg, &new_deq); + + /* Search wrapped around, bail out */ + if (new_deq == ep->ring->dequeue) { + xhci_err(xhci, "Error: Failed finding new dequeue state\n"); + state->new_deq_seg = NULL; + state->new_deq_ptr = NULL; + return; + } + + } while (!cycle_found || !td_last_trb_found); - /* Increment to find next TRB after last_trb. Cycle if appropriate. */ - trb = &state->new_deq_ptr->generic; - if (TRB_TYPE_LINK_LE32(trb->field[3]) && - (trb->field[3] & cpu_to_le32(LINK_TOGGLE))) - state->new_cycle_state ^= 0x1; - next_trb(xhci, ep_ring, &state->new_deq_seg, &state->new_deq_ptr); + state->new_deq_seg = new_seg; + state->new_deq_ptr = new_deq; /* Don't update the ring cycle state for the producer (us). */ xhci_dbg(xhci, "Cycle state = 0x%x\n", state->new_cycle_state); diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c index 457a7ac1fef7..4cc1804d6a44 100644 --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -2819,6 +2819,9 @@ void xhci_cleanup_stalled_ring(struct xhci_hcd *xhci, ep_index, ep->stopped_stream, ep->stopped_td, &deq_state); + if (!deq_state.new_deq_ptr || !deq_state.new_deq_seg) + return; + /* HW with the reset endpoint quirk will use the saved dequeue state to * issue a configure endpoint command later. */ -- 2.39.2