usb: xhci: Add support for URB_ZERO_PACKET to bulk/sg transfers

This commit checks for the URB_ZERO_PACKET flag and creates an extra
zero-length td if the urb transfer length is a multiple of the endpoint's
max packet length.

Signed-off-by: Reyad Attiyat <reyad.attiyat@gmail.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 6a8fc52aed5863391885ac11c2661a407f707a30..463562d119297ec7d4319cf11664a4e8d0fa9e7d 100644 (file)
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -3041,9 +3041,11 @@ static int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
        struct xhci_td *td;
        struct scatterlist *sg;
        int num_sgs;
-       int trb_buff_len, this_sg_len, running_total;
+       int trb_buff_len, this_sg_len, running_total, ret;
        unsigned int total_packet_count;
+       bool zero_length_needed;
        bool first_trb;
+       int last_trb_num;
        u64 addr;
        bool more_trbs_coming;
 
@@ -3059,13 +3061,27 @@ static int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
        total_packet_count = DIV_ROUND_UP(urb->transfer_buffer_length,
                        usb_endpoint_maxp(&urb->ep->desc));
 
-       trb_buff_len = prepare_transfer(xhci, xhci->devs[slot_id],
+       ret = prepare_transfer(xhci, xhci->devs[slot_id],
                        ep_index, urb->stream_id,
                        num_trbs, urb, 0, mem_flags);
-       if (trb_buff_len < 0)
-               return trb_buff_len;
+       if (ret < 0)
+               return ret;
 
        urb_priv = urb->hcpriv;
+
+       /* Deal with URB_ZERO_PACKET - need one more td/trb */
+       zero_length_needed = urb->transfer_flags & URB_ZERO_PACKET &&
+               urb_priv->length == 2;
+       if (zero_length_needed) {
+               num_trbs++;
+               xhci_dbg(xhci, "Creating zero length td.\n");
+               ret = prepare_transfer(xhci, xhci->devs[slot_id],
+                               ep_index, urb->stream_id,
+                               1, urb, 1, mem_flags);
+               if (ret < 0)
+                       return ret;
+       }
+
        td = urb_priv->td[0];
 
        /*
@@ -3095,6 +3111,7 @@ static int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
                trb_buff_len = urb->transfer_buffer_length;
 
        first_trb = true;
+       last_trb_num = zero_length_needed ? 2 : 1;
        /* Queue the first TRB, even if it's zero-length */
        do {
                u32 field = 0;
@@ -3112,12 +3129,15 @@ static int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
                /* Chain all the TRBs together; clear the chain bit in the last
                 * TRB to indicate it's the last TRB in the chain.
                 */
-               if (num_trbs > 1) {
+               if (num_trbs > last_trb_num) {
                        field |= TRB_CHAIN;
-               } else {
-                       /* FIXME - add check for ZERO_PACKET flag before this */
+               } else if (num_trbs == last_trb_num) {
                        td->last_trb = ep_ring->enqueue;
                        field |= TRB_IOC;
+               } else if (zero_length_needed && num_trbs == 1) {
+                       trb_buff_len = 0;
+                       urb_priv->td[1]->last_trb = ep_ring->enqueue;
+                       field |= TRB_IOC;
                }
 
                /* Only set interrupt on short packet for IN endpoints */
@@ -3179,7 +3199,7 @@ static int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
                if (running_total + trb_buff_len > urb->transfer_buffer_length)
                        trb_buff_len =
                                urb->transfer_buffer_length - running_total;
-       } while (running_total < urb->transfer_buffer_length);
+       } while (num_trbs > 0);
 
        check_trb_math(urb, num_trbs, running_total);
        giveback_first_trb(xhci, slot_id, ep_index, urb->stream_id,
@@ -3197,7 +3217,9 @@ int xhci_queue_bulk_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
        int num_trbs;
        struct xhci_generic_trb *start_trb;
        bool first_trb;
+       int last_trb_num;
        bool more_trbs_coming;
+       bool zero_length_needed;
        int start_cycle;
        u32 field, length_field;
 
@@ -3228,7 +3250,6 @@ int xhci_queue_bulk_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
                num_trbs++;
                running_total += TRB_MAX_BUFF_SIZE;
        }
-       /* FIXME: this doesn't deal with URB_ZERO_PACKET - need one more */
 
        ret = prepare_transfer(xhci, xhci->devs[slot_id],
                        ep_index, urb->stream_id,
@@ -3237,6 +3258,20 @@ int xhci_queue_bulk_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
                return ret;
 
        urb_priv = urb->hcpriv;
+
+       /* Deal with URB_ZERO_PACKET - need one more td/trb */
+       zero_length_needed = urb->transfer_flags & URB_ZERO_PACKET &&
+               urb_priv->length == 2;
+       if (zero_length_needed) {
+               num_trbs++;
+               xhci_dbg(xhci, "Creating zero length td.\n");
+               ret = prepare_transfer(xhci, xhci->devs[slot_id],
+                               ep_index, urb->stream_id,
+                               1, urb, 1, mem_flags);
+               if (ret < 0)
+                       return ret;
+       }
+
        td = urb_priv->td[0];
 
        /*
@@ -3258,7 +3293,7 @@ int xhci_queue_bulk_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
                trb_buff_len = urb->transfer_buffer_length;
 
        first_trb = true;
-
+       last_trb_num = zero_length_needed ? 2 : 1;
        /* Queue the first TRB, even if it's zero-length */
        do {
                u32 remainder = 0;
@@ -3275,12 +3310,15 @@ int xhci_queue_bulk_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
                /* Chain all the TRBs together; clear the chain bit in the last
                 * TRB to indicate it's the last TRB in the chain.
                 */
-               if (num_trbs > 1) {
+               if (num_trbs > last_trb_num) {
                        field |= TRB_CHAIN;
-               } else {
-                       /* FIXME - add check for ZERO_PACKET flag before this */
+               } else if (num_trbs == last_trb_num) {
                        td->last_trb = ep_ring->enqueue;
                        field |= TRB_IOC;
+               } else if (zero_length_needed && num_trbs == 1) {
+                       trb_buff_len = 0;
+                       urb_priv->td[1]->last_trb = ep_ring->enqueue;
+                       field |= TRB_IOC;
                }
 
                /* Only set interrupt on short packet for IN endpoints */
@@ -3318,7 +3356,7 @@ int xhci_queue_bulk_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
                trb_buff_len = urb->transfer_buffer_length - running_total;
                if (trb_buff_len > TRB_MAX_BUFF_SIZE)
                        trb_buff_len = TRB_MAX_BUFF_SIZE;
-       } while (running_total < urb->transfer_buffer_length);
+       } while (num_trbs > 0);
 
        check_trb_math(urb, num_trbs, running_total);
        giveback_first_trb(xhci, slot_id, ep_index, urb->stream_id,

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 91fd328353120e526f421dd723329099d0f8d94e..6b0f4a47e4021d83e01fb76a0a1aa18d6b3ca793 100644 (file)
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -1340,6 +1340,11 @@ int xhci_urb_enqueue(struct usb_hcd *hcd, struct urb *urb, gfp_t mem_flags)
 
        if (usb_endpoint_xfer_isoc(&urb->ep->desc))
                size = urb->number_of_packets;
+       else if (usb_endpoint_is_bulk_out(&urb->ep->desc) &&
+           urb->transfer_buffer_length > 0 &&
+           urb->transfer_flags & URB_ZERO_PACKET &&
+           !(urb->transfer_buffer_length % usb_endpoint_maxp(&urb->ep->desc)))
+               size = 2;
        else
                size = 1;