USB: musb: respect usb_request->zero in control requests

In gadget mode the answer to a control request should be followed by
a zero-length packet if the amount transferred is an exact multiple of
the endpoint's packet size and the requests has its "zero" flag set.

This patch prevents the request from being immediately removed from the
queue when a control IN transfer ends on a full packet and "zero" is set.
The next time ep0_txstate is entered, a zero-length packet is queued and
the request is removed as fifo_count is 0.

Signed-off-by: Daniel Glöckner <dg@emlix.com>
Signed-off-by: Ajay Kumar Gupta <ajay.gupta@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/musb/musb_gadget_ep0.c b/drivers/usb/musb/musb_gadget_ep0.c
index 7a6778675ad3a8d5a76d1f8de9477a8c48309d12..522efb31b56b5304a0f2d52b4e232749f8c6a319 100644 (file)
--- a/drivers/usb/musb/musb_gadget_ep0.c
+++ b/drivers/usb/musb/musb_gadget_ep0.c
@@ -511,7 +511,8 @@ static void ep0_txstate(struct musb *musb)
 
        /* update the flags */
        if (fifo_count < MUSB_MAX_END0_PACKET
-                       || request->actual == request->length) {
+                       || (request->actual == request->length
+                               && !request->zero)) {
                musb->ep0_state = MUSB_EP0_STAGE_STATUSOUT;
                csr |= MUSB_CSR0_P_DATAEND;
        } else