[PATCH v3 20/26] staging: most: usb: clear functional stall on tx endpoint

[Christian Gromm]

This patch triggers the host to send a control request to
clear the endpoint's Halt feature.

Signed-off-by: Christian Gromm <christian.gromm at microchip.com>
---
v2: fix patch numeration
v3: - add cover letter
    - create patches with -M switch to make file movement visible

 drivers/staging/most/usb/usb.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/staging/most/usb/usb.c b/drivers/staging/most/usb/usb.c
index 0624ca9..7577351 100644
--- a/drivers/staging/most/usb/usb.c
+++ b/drivers/staging/most/usb/usb.c
@@ -815,6 +815,21 @@ static void wq_clear_halt(struct work_struct *wq_obj)
 	if (usb_clear_halt(mdev->usb_device, pipe))
 		dev_warn(&mdev->usb_device->dev, "Failed to reset endpoint.\n");
 
+	/* If the functional Stall condition has been set on an
+	 * asynchronous rx channel, we need to clear the tx channel
+	 * too, since the hardware runs its clean-up sequence on both
+	 * channels, as they are physically one on the network.
+	 *
+	 * The USB interface that exposes the asynchronous channels
+	 * contains always two endpoints, and two only.
+	 */
+	if (mdev->conf[channel].data_type == MOST_CH_ASYNC &&
+	    mdev->conf[channel].direction == MOST_CH_RX) {
+		int peer = 1 - channel;
+		int snd_pipe = usb_sndbulkpipe(mdev->usb_device,
+					       mdev->ep_address[peer]);
+		usb_clear_halt(mdev->usb_device, snd_pipe);
+	}
 	mdev->is_channel_healthy[channel] = true;
 	most_resume_enqueue(&mdev->iface, channel);
 	mutex_unlock(&mdev->io_mutex);
-- 
1.9.1