usb: cdnsp: Fixed issue with ZLP

The condition "if (need_zero_pkt && zero_len_trb)" was always false
and it caused that TRB for ZLP was not prepared.

Fix causes that after preparing last TRB in TD, the driver prepares
additional TD with ZLP when a ZLP is required.

Cc: <stable@vger.kernel.org>
Fixes: 3d82904559f4 ("usb: cdnsp: cdns3 Add main part of Cadence USBSSP DRD Driver")
Signed-off-by: Pawel Laszczak <pawell@cadence.com>
Link: https://lore.kernel.org/r/20210623072728.41275-1-pawell@gli-login.cadence.com
Signed-off-by: Peter Chen <peter.chen@kernel.org>

diff --git a/drivers/usb/cdns3/cdnsp-ring.c b/drivers/usb/cdns3/cdnsp-ring.c
index 68972746e3636fadee03ad009a7c615e716db75d..1b1438457fb0437a862430e2ed6743688c4b7aad 100644 (file)
--- a/drivers/usb/cdns3/cdnsp-ring.c
+++ b/drivers/usb/cdns3/cdnsp-ring.c
@@ -1932,15 +1932,13 @@ int cdnsp_queue_bulk_tx(struct cdnsp_device *pdev, struct cdnsp_request *preq)
                }
 
                if (enqd_len + trb_buff_len >= full_len) {
-                       if (need_zero_pkt && zero_len_trb) {
-                               zero_len_trb = true;
-                       } else {
-                               field &= ~TRB_CHAIN;
-                               field |= TRB_IOC;
-                               more_trbs_coming = false;
-                               need_zero_pkt = false;
-                               preq->td.last_trb = ring->enqueue;
-                       }
+                       if (need_zero_pkt)
+                               zero_len_trb = !zero_len_trb;
+
+                       field &= ~TRB_CHAIN;
+                       field |= TRB_IOC;
+                       more_trbs_coming = false;
+                       preq->td.last_trb = ring->enqueue;
                }
 
                /* Only set interrupt on short packet for OUT endpoints. */
@@ -1955,7 +1953,7 @@ int cdnsp_queue_bulk_tx(struct cdnsp_device *pdev, struct cdnsp_request *preq)
                length_field = TRB_LEN(trb_buff_len) | TRB_TD_SIZE(remainder) |
                        TRB_INTR_TARGET(0);
 
-               cdnsp_queue_trb(pdev, ring, more_trbs_coming | need_zero_pkt,
+               cdnsp_queue_trb(pdev, ring, more_trbs_coming | zero_len_trb,
                                lower_32_bits(send_addr),
                                upper_32_bits(send_addr),
                                length_field,