If URB_ZERO_PACKET is set then make sure that the last usb message
sent isn't a full sized one. A partial transfer is needed to terminate
variable length bulk output (eg ethernet frames).
URB_ZERO_PACKET is easily implemented by increasing td_residue
to account for the extra packet.
Signed-off-by: David Laight <david.laight@xxxxxxxxxx>
---
drivers/usb/host/xhci-ring.c | 29 ++++++++++++++++++++++-------
1 file changed, 22 insertions(+), 7 deletions(-)
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index afd8eeb..1324bb0 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -3296,10 +3296,25 @@ static int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
* td_residue is set so that td_residue/max_packet is the number of
* packets required to send the data after the current partial
* transfer(s) have completed.
+ *
+ * If URB_ZERO_PACKET is unset td_residue - urb->transfer_buffer_length
+ * is always less than or equal to 2 * (max_packet - 1).
+ * If a ZLP is needed the difference is 2 * max_packet - 1.
*/
max_packet = GET_MAX_PACKET(usb_endpoint_maxp(&urb->ep->desc));
- td_residue = urb->transfer_buffer_length;
- td_residue = ALIGN(td_residue, max_packet) + max_packet - 1;
+ td_residue = ALIGN(urb->transfer_buffer_length, max_packet);
+ /* If URB_ZERO_PACKET is set we might need another message. */
+ if (urb->transfer_flags & URB_ZERO_PACKET &&
+ td_residue == urb->transfer_buffer_length) {
+ /*
+ * For v1.0 hosts we could set the last TRB with td_size == 1,
+ * but for older hosts we need an extra TRB.
+ */
+ num_trbs++;
+ /* The td_size in earlier fragments needs to be 1 higher */
+ td_residue += max_packet;
+ }
+ td_residue += max_packet - 1;
ret = prepare_transfer(xhci, xhci->devs[slot_id],
ep_index, urb->stream_id,
@@ -3343,11 +3358,12 @@ static int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
*/
trb_buff_len = (~addr & (TRB_MAX_BUFF_SIZE - 1)) + 1;
trb_buff_len = min_t(u32, trb_buff_len, this_sg_len);
+ trb_buff_len = min_t(u32, trb_buff_len, len_left);
/* Check for last fragment... */
- if (trb_buff_len >= len_left) {
- /* FIXME - add check for ZERO_PACKET flag before this */
- trb_buff_len = len_left;
+ td_residue -= trb_buff_len;
+ if (trb_buff_len == len_left && (len_left == 0 ||
+ td_residue < 2 * max_packet - 1)) {
urb_priv = urb->hcpriv;
urb_priv->td[0]->last_trb = ep_ring->enqueue;
/* Request interrupt and clear chain */
@@ -3356,7 +3372,6 @@ static int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
} else {
if (trb_buff_len == 0)
goto next_frag;
- td_residue -= trb_buff_len;
}
/* Set the correct cycle bit (inverted for first TRB). */
@@ -3391,7 +3406,7 @@ static int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
/* Advance source data pointer */
this_sg_len -= trb_buff_len;
next_frag:
- if (this_sg_len == 0) {
+ if (this_sg_len == 0 && len_left != 0) {
sg = sg_next(sg);
addr = (u64) sg_dma_address(sg);
this_sg_len = sg_dma_len(sg);
--
1.8.1.2
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