From b008df60c6369ba0290fa7daa177375407a12e07 Mon Sep 17 00:00:00 2001 From: Andiry Xu Date: Mon, 5 Mar 2012 17:49:34 +0800 Subject: [PATCH] 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 Signed-off-by: Sarah Sharp Tested-by: Paul Zimmerman --- drivers/usb/host/xhci-mem.c | 6 ++ drivers/usb/host/xhci-ring.c | 105 +++++++++++++++++++---------------- drivers/usb/host/xhci.c | 1 + drivers/usb/host/xhci.h | 2 + 4 files changed, 67 insertions(+), 47 deletions(-) diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c index bdea4de867b4..212012c97df3 100644 --- a/drivers/usb/host/xhci-mem.c +++ b/drivers/usb/host/xhci-mem.c @@ -135,6 +135,12 @@ static void xhci_initialize_ring_info(struct xhci_ring *ring) /* Not necessary for new rings, but needed for re-initialized rings */ ring->enq_updates = 0; ring->deq_updates = 0; + + /* + * Each segment has a link TRB, and leave an extra TRB for SW + * accounting purpose + */ + ring->num_trbs_free = ring->num_segs * (TRBS_PER_SEGMENT - 1) - 1; } /** diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c index ad68a28d8fe6..f9b6fa364f22 100644 --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -145,10 +145,17 @@ static void next_trb(struct xhci_hcd *xhci, */ static void inc_deq(struct xhci_hcd *xhci, struct xhci_ring *ring) { - union xhci_trb *next = ++(ring->dequeue); + union xhci_trb *next; unsigned long long addr; ring->deq_updates++; + + /* If this is not event ring, there is one more usable TRB */ + if (ring->type != TYPE_EVENT && + !last_trb(xhci, ring, ring->deq_seg, ring->dequeue)) + ring->num_trbs_free++; + next = ++(ring->dequeue); + /* Update the dequeue pointer further if that was a link TRB or we're at * the end of an event ring segment (which doesn't have link TRBS) */ @@ -189,6 +196,10 @@ static void inc_enq(struct xhci_hcd *xhci, struct xhci_ring *ring, unsigned long long addr; chain = le32_to_cpu(ring->enqueue->generic.field[3]) & TRB_CHAIN; + /* If this is not event ring, there is one less usable TRB */ + if (ring->type != TYPE_EVENT && + !last_trb(xhci, ring, ring->enq_seg, ring->enqueue)) + ring->num_trbs_free--; next = ++(ring->enqueue); ring->enq_updates++; @@ -240,54 +251,14 @@ static void inc_enq(struct xhci_hcd *xhci, struct xhci_ring *ring, /* * Check to see if there's room to enqueue num_trbs on the ring. See rules * above. - * FIXME: this would be simpler and faster if we just kept track of the number - * of free TRBs in a ring. */ -static int room_on_ring(struct xhci_hcd *xhci, struct xhci_ring *ring, +static inline int room_on_ring(struct xhci_hcd *xhci, struct xhci_ring *ring, unsigned int num_trbs) { - int i; - union xhci_trb *enq = ring->enqueue; - struct xhci_segment *enq_seg = ring->enq_seg; - 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 */ - left_on_ring = TRBS_PER_SEGMENT - 1; - for (cur_seg = enq_seg->next; cur_seg != enq_seg; - cur_seg = cur_seg->next) - left_on_ring += TRBS_PER_SEGMENT - 1; - - /* Always need one TRB free in the ring. */ - left_on_ring -= 1; - if (num_trbs > left_on_ring) { - xhci_warn(xhci, "Not enough room on ring; " - "need %u TRBs, %u TRBs left\n", - num_trbs, left_on_ring); - return 0; - } + if (ring->num_trbs_free >= num_trbs) return 1; - } - /* Make sure there's an extra empty TRB available */ - for (i = 0; i <= num_trbs; ++i) { - if (enq == ring->dequeue) - return 0; - enq++; - while (last_trb(xhci, ring, enq_seg, enq)) { - enq_seg = enq_seg->next; - enq = enq_seg->trbs; - } - } - return 1; + + return 0; } /* Ring the host controller doorbell after placing a command on the ring */ @@ -893,6 +864,43 @@ void xhci_stop_endpoint_command_watchdog(unsigned long arg) xhci_dbg(xhci, "xHCI host controller is dead.\n"); } + +static void update_ring_for_set_deq_completion(struct xhci_hcd *xhci, + struct xhci_virt_device *dev, + struct xhci_ring *ep_ring, + unsigned int ep_index) +{ + union xhci_trb *dequeue_temp; + int num_trbs_free_temp; + bool revert = false; + + num_trbs_free_temp = ep_ring->num_trbs_free; + dequeue_temp = ep_ring->dequeue; + + while (ep_ring->dequeue != dev->eps[ep_index].queued_deq_ptr) { + /* We have more usable TRBs */ + ep_ring->num_trbs_free++; + ep_ring->dequeue++; + if (last_trb(xhci, ep_ring, ep_ring->deq_seg, + ep_ring->dequeue)) { + if (ep_ring->dequeue == + dev->eps[ep_index].queued_deq_ptr) + break; + ep_ring->deq_seg = ep_ring->deq_seg->next; + ep_ring->dequeue = ep_ring->deq_seg->trbs; + } + if (ep_ring->dequeue == dequeue_temp) { + revert = true; + break; + } + } + + if (revert) { + xhci_dbg(xhci, "Unable to find new dequeue pointer\n"); + ep_ring->num_trbs_free = num_trbs_free_temp; + } +} + /* * When we get a completion for a Set Transfer Ring Dequeue Pointer command, * we need to clear the set deq pending flag in the endpoint ring state, so that @@ -974,8 +982,8 @@ static void handle_set_deq_completion(struct xhci_hcd *xhci, /* Update the ring's dequeue segment and dequeue pointer * to reflect the new position. */ - ep_ring->deq_seg = dev->eps[ep_index].queued_deq_seg; - ep_ring->dequeue = dev->eps[ep_index].queued_deq_ptr; + update_ring_for_set_deq_completion(xhci, dev, + ep_ring, ep_index); } else { xhci_warn(xhci, "Mismatch between completed Set TR Deq " "Ptr command & xHCI internal state.\n"); @@ -3407,6 +3415,7 @@ cleanup: ep_ring->enqueue = urb_priv->td[0]->first_trb; ep_ring->enq_seg = urb_priv->td[0]->start_seg; ep_ring->cycle_state = start_cycle; + ep_ring->num_trbs_free = ep_ring->num_trbs_free_temp; usb_hcd_unlink_urb_from_ep(bus_to_hcd(urb->dev->bus), urb); return ret; } @@ -3479,6 +3488,8 @@ int xhci_queue_isoc_tx_prepare(struct xhci_hcd *xhci, gfp_t mem_flags, urb->dev->speed == USB_SPEED_FULL) urb->interval /= 8; } + ep_ring->num_trbs_free_temp = ep_ring->num_trbs_free; + return xhci_queue_isoc_tx(xhci, GFP_ATOMIC, urb, slot_id, ep_index); } 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. diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h index 2337a8e80b60..ea8fc237d158 100644 --- a/drivers/usb/host/xhci.h +++ b/drivers/usb/host/xhci.h @@ -1278,6 +1278,8 @@ struct xhci_ring { u32 cycle_state; unsigned int stream_id; unsigned int num_segs; + unsigned int num_trbs_free; + unsigned int num_trbs_free_temp; enum xhci_ring_type type; bool last_td_was_short; }; -- 2.39.2