From 680cc64557101eaaca706dc9a1a0777f35aac0da Mon Sep 17 00:00:00 2001 From: =?utf8?q?Daniel=20Gl=C3=B6ckner?= Date: Thu, 28 May 2009 13:00:14 +0200 Subject: [PATCH] USB: gadget: imx_udc: don't queue more data when zlp is to be sent MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit When a zero-length packet has been requested and another packet is written into the fifo, the MX1 tends to send the first byte of the previous packet instead of the first byte of the current packet. The CRC is adjusted accordingly so that this packet is _not_ discarded by the host. Waiting for the ZLPS bit to clear avoids these bad packets. Signed-off-by: Daniel Glöckner Cc: Darius Augulis Cc: David Brownell Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/imx_udc.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/usb/gadget/imx_udc.c b/drivers/usb/gadget/imx_udc.c index 239bf8ed9f4a..c52a681f376c 100644 --- a/drivers/usb/gadget/imx_udc.c +++ b/drivers/usb/gadget/imx_udc.c @@ -415,6 +415,13 @@ static int write_packet(struct imx_ep_struct *imx_ep, struct imx_request *req) u8 *buf; int length, count, temp; + if (unlikely(__raw_readl(imx_ep->imx_usb->base + + USB_EP_STAT(EP_NO(imx_ep))) & EPSTAT_ZLPS)) { + D_TRX(imx_ep->imx_usb->dev, "<%s> zlp still queued in EP %s\n", + __func__, imx_ep->ep.name); + return -1; + } + buf = req->req.buf + req->req.actual; prefetch(buf); -- 2.20.1