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Commit 9db33f31 authored by Alan Stern's avatar Alan Stern Committed by Greg Kroah-Hartman
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USB: IMX21: upgrade the isochronous API 



This patch attempts to update the imx21-hcd driver to the current
standard for the isochronous API.  Firstly, urb->start_frame should
always be set by the driver; it is not an input parameter.  Secondly,
the URB_ISO_ASAP flag matters only when an URB is submitted to a
stream that has gotten an underrun.  It causes the URB to be scheduled
for the next available slot in the future, rather than the earliest
unused (and expired) slot.

Unfortunately, I don't have any way to test these changes.

Signed-off-by: default avatarAlan Stern <stern@rowland.harvard.edu>
CC: Sascha Hauer <kernel@pengutronix.de>
CC: Martin Fuzzey <mfuzzey@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 8a1ea51f

drivers/usb/host/imx21-hcd.c

+26 −17
Original line number Diff line number Diff line
@@ -809,26 +809,36 @@ static int imx21_hc_urb_enqueue_isoc(struct usb_hcd *hcd, 


	/* calculate frame */

	cur_frame = imx21_hc_get_frame(hcd);

	if (urb->transfer_flags & URB_ISO_ASAP) {

		if (list_empty(&ep_priv->td_list))

			urb->start_frame = cur_frame + 5;

		else

			urb->start_frame = list_entry(

				ep_priv->td_list.prev,

				struct td, list)->frame + urb->interval;

	}

	urb->start_frame = wrap_frame(urb->start_frame);

	i = 0;

	if (list_empty(&ep_priv->td_list)) {

		urb->start_frame = wrap_frame(cur_frame + 5);

	} else {

		urb->start_frame = wrap_frame(list_entry(ep_priv->td_list.prev,

				struct td, list)->frame + urb->interval);



		if (frame_after(cur_frame, urb->start_frame)) {

			dev_dbg(imx21->dev,

				"enqueue: adjusting iso start %d (cur=%d) asap=%d\n",

				urb->start_frame, cur_frame,

				(urb->transfer_flags & URB_ISO_ASAP) != 0);

		urb->start_frame = wrap_frame(cur_frame + 1);

			i = DIV_ROUND_UP(wrap_frame(

					cur_frame - urb->start_frame),

					urb->interval);

			if (urb->transfer_flags & URB_ISO_ASAP) {

				urb->start_frame = wrap_frame(urb->start_frame

						+ i * urb->interval);

				i = 0;

			} else if (i >= urb->number_of_packets) {

				ret = -EXDEV;

				goto alloc_dmem_failed;

			}

		}

	}



	/* set up transfers */

	urb_priv->isoc_remaining = urb->number_of_packets - i;

	td = urb_priv->isoc_td;

	for (i = 0; i < urb->number_of_packets; i++, td++) {

	for (; i < urb->number_of_packets; i++, td++) {

		unsigned int offset = urb->iso_frame_desc[i].offset;

		td->ep = ep;

		td->urb = urb;
@@ -840,7 +850,6 @@ static int imx21_hc_urb_enqueue_isoc(struct usb_hcd *hcd, 
		list_add_tail(&td->list, &ep_priv->td_list);

	}



	urb_priv->isoc_remaining = urb->number_of_packets;

	dev_vdbg(imx21->dev, "setup %d packets for iso frame %d->%d\n",

		urb->number_of_packets, urb->start_frame, td->frame);