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Message-Id: <1435538198-3509-1-git-send-email-reyad.attiyat@gmail.com>
Date: Sun, 28 Jun 2015 19:36:38 -0500
From: Reyad Attiyat <reyad.attiyat@...il.com>
To: gregkh@...uxfoundation.org, mathias.nyman@...el.com
Cc: linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
Reyad Attiyat <reyad.attiyat@...il.com>
Subject: [PATCH] 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
max packet length.
Signed-off-by: Reyad Attiyat <reyad.attiyat@...il.com>
---
drivers/usb/host/xhci-ring.c | 41 ++++++++++++++++++++++++++++++++---------
1 file changed, 32 insertions(+), 9 deletions(-)
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 7d34cbf..fb24099 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -3040,7 +3040,9 @@ static int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
int num_sgs;
int trb_buff_len, this_sg_len, running_total;
unsigned int total_packet_count;
+ bool zero_length_needed;
bool first_trb;
+ int last_trb;
u64 addr;
bool more_trbs_coming;
@@ -3056,6 +3058,14 @@ 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));
+ /* Deal with URB_ZERO_PACKET - need one more td/trb */
+ zero_length_needed = (urb->transfer_flags & URB_ZERO_PACKET)
+ && !(urb->transfer_buffer_length % usb_endpoint_maxp(&urb->ep->desc));
+ if(zero_length_needed){
+ num_trbs++;
+ xhci_dbg(xhci, "Creating zero length td.\n");
+ }
+
trb_buff_len = prepare_transfer(xhci, xhci->devs[slot_id],
ep_index, urb->stream_id,
num_trbs, urb, 0, mem_flags);
@@ -3092,6 +3102,7 @@ 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 = zero_length_needed ? 2 : 1;
/* Queue the first TRB, even if it's zero-length */
do {
u32 field = 0;
@@ -3109,12 +3120,13 @@ 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) {
field |= TRB_CHAIN;
- } else {
- /* FIXME - add check for ZERO_PACKET flag before this */
+ } else if (num_trbs == last_trb) {
td->last_trb = ep_ring->enqueue;
field |= TRB_IOC;
+ } else if (zero_length_needed && num_trbs == 1) {
+ trb_buff_len = 0;
}
/* Only set interrupt on short packet for IN endpoints */
@@ -3194,7 +3206,9 @@ 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;
bool more_trbs_coming;
+ bool zero_length_needed;
int start_cycle;
u32 field, length_field;
@@ -3225,7 +3239,14 @@ 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 */
+
+ /* Deal with URB_ZERO_PACKET - need one more td/trb */
+ zero_length_needed = (urb->transfer_flags & URB_ZERO_PACKET)
+ && !(urb->transfer_buffer_length % usb_endpoint_maxp(&urb->ep->desc));
+ 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,
@@ -3255,7 +3276,7 @@ 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 = zero_length_needed ? 2 : 1;
/* Queue the first TRB, even if it's zero-length */
do {
u32 remainder = 0;
@@ -3272,12 +3293,14 @@ 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) {
field |= TRB_CHAIN;
- } else {
- /* FIXME - add check for ZERO_PACKET flag before this */
+ } else if (num_trbs == last_trb) {
td->last_trb = ep_ring->enqueue;
field |= TRB_IOC;
+ } else if (zero_length_needed && num_trbs == 1) {
+ trb_buff_len = 0;
}
/* Only set interrupt on short packet for IN endpoints */
@@ -3315,7 +3338,7 @@ 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,
--
2.4.3
--
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