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authorManu Gautam <mgautam@codeaurora.org>2017-07-19 17:07:10 +0530
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-10-21 17:21:39 +0200
commit480fd4fb29c596bf669a864ceda00dec7f0c2134 (patch)
treee4453390d184def3b78278497342efad798bc869
parent9b9843154cd1d6916f49a1a95c9b49c7cee9c477 (diff)
usb: dwc3: gadget: Correct ISOC DATA PIDs for short packets
commit 40d829fb2ec636b6b4b0cc95e2546ab9aca04cc9 upstream. The PIDs for Isochronous data transfers are incorrect for high bandwidth IN endpoints when the request length is less than EP wMaxPacketSize. As per spec correct PIDs for ISOC data transfers are: 1) For request length <= maxpacket - DATA0, 2) For maxpacket < length <= (2 * maxpacket) - DATA1, DATA0 3) For (2 * maxpacket) < length <= (3 * maxpacket) - DATA2, DATA1, DATA0. But driver always sets PCM fields based on wMaxPacketSize due to which DATA2 happens even for small requests. Fix this by setting the PCM field of trb->size depending on request length rather than fixing it to the value depending on wMaxPacketSize. Ideally it shouldn't give any issues as dwc3 will send 0-length packet for next IN token if host sends (even after receiving a short packet). Windows seems to ignore this but with MacOS frame loss observed when using f_uvc. Signed-off-by: Manu Gautam <mgautam@codeaurora.org> Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com> [b-liu@ti.com added following change for v4.9.] - unsigned int maxp = usb_endpoint_maxp(ep->desc); + unsigned int maxp; + maxp = usb_endpoint_maxp(ep->desc) & 0x07ff; Signed-off-by: Bin Liu <b-liu@ti.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/usb/dwc3/gadget.c35
1 files changed, 34 insertions, 1 deletions
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index f92c680e3937..c61ddbf94bc7 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -817,9 +817,42 @@ static void dwc3_prepare_one_trb(struct dwc3_ep *dep,
if (!node) {
trb->ctrl = DWC3_TRBCTL_ISOCHRONOUS_FIRST;
+ /*
+ * USB Specification 2.0 Section 5.9.2 states that: "If
+ * there is only a single transaction in the microframe,
+ * only a DATA0 data packet PID is used. If there are
+ * two transactions per microframe, DATA1 is used for
+ * the first transaction data packet and DATA0 is used
+ * for the second transaction data packet. If there are
+ * three transactions per microframe, DATA2 is used for
+ * the first transaction data packet, DATA1 is used for
+ * the second, and DATA0 is used for the third."
+ *
+ * IOW, we should satisfy the following cases:
+ *
+ * 1) length <= maxpacket
+ * - DATA0
+ *
+ * 2) maxpacket < length <= (2 * maxpacket)
+ * - DATA1, DATA0
+ *
+ * 3) (2 * maxpacket) < length <= (3 * maxpacket)
+ * - DATA2, DATA1, DATA0
+ */
if (speed == USB_SPEED_HIGH) {
struct usb_ep *ep = &dep->endpoint;
- trb->size |= DWC3_TRB_SIZE_PCM1(ep->mult - 1);
+ unsigned int mult = ep->mult - 1;
+ unsigned int maxp;
+
+ maxp = usb_endpoint_maxp(ep->desc) & 0x07ff;
+
+ if (length <= (2 * maxp))
+ mult--;
+
+ if (length <= maxp)
+ mult--;
+
+ trb->size |= DWC3_TRB_SIZE_PCM1(mult);
}
} else {
trb->ctrl = DWC3_TRBCTL_ISOCHRONOUS;