[PATCH] USBATM: allow isochronous transfer

While the usbatm core has had some support for using isoc urbs
for some time, there was no way for users to turn it on.  While
use of isoc transfer should still be considered experimental, it
now works well enough to let users turn it on.  Minidrivers signal
to the core that they want to use isoc transfer by setting the new
UDSL_USE_ISOC flag.  The speedtch minidriver gets a new module
parameter enable_isoc (defaults to false), plus some logic that
checks for the existence of an isoc receive endpoint (not all
speedtouch modems have one).

Signed-off-by: Duncan Sands <baldrick@free.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 15 insertions, 15 deletions

diff --git a/drivers/usb/atm/usbatm.c b/drivers/usb/atm/usbatm.c
index 1d829c29c86..923f2d9269b 100644
--- a/drivers/usb/atm/usbatm.c
+++ b/drivers/usb/atm/usbatm.c
@@ -1049,17 +1049,23 @@ int usbatm_usb_probe(struct usb_interface *intf, const struct usb_device_id *id,
 	init_completion(&instance->thread_exited);
 
 	INIT_LIST_HEAD(&instance->vcc_list);
+	skb_queue_head_init(&instance->sndqueue);
 
 	usbatm_init_channel(&instance->rx_channel);
 	usbatm_init_channel(&instance->tx_channel);
 	tasklet_init(&instance->rx_channel.tasklet, usbatm_rx_process, (unsigned long)instance);
 	tasklet_init(&instance->tx_channel.tasklet, usbatm_tx_process, (unsigned long)instance);
-	instance->rx_channel.endpoint = usb_rcvbulkpipe(usb_dev, driver->in);
-	instance->tx_channel.endpoint = usb_sndbulkpipe(usb_dev, driver->out);
 	instance->rx_channel.stride = ATM_CELL_SIZE + driver->rx_padding;
 	instance->tx_channel.stride = ATM_CELL_SIZE + driver->tx_padding;
 	instance->rx_channel.usbatm = instance->tx_channel.usbatm = instance;
 
+	if ((instance->flags & UDSL_USE_ISOC) && driver->isoc_in)
+		instance->rx_channel.endpoint = usb_rcvisocpipe(usb_dev, driver->isoc_in);
+	else
+		instance->rx_channel.endpoint = usb_rcvbulkpipe(usb_dev, driver->bulk_in);
+
+	instance->tx_channel.endpoint = usb_sndbulkpipe(usb_dev, driver->bulk_out);
+
 	/* tx buffer size must be a positive multiple of the stride */
 	instance->tx_channel.buf_size = max (instance->tx_channel.stride,
 			snd_buf_bytes - (snd_buf_bytes % instance->tx_channel.stride));
@@ -1080,6 +1086,7 @@ int usbatm_usb_probe(struct usb_interface *intf, const struct usb_device_id *id,
 		num_packets--;
 
 	instance->rx_channel.buf_size = num_packets * maxpacket;
+	instance->rx_channel.packet_size = maxpacket;
 
 #ifdef DEBUG
 	for (i = 0; i < 2; i++) {
@@ -1090,22 +1097,16 @@ int usbatm_usb_probe(struct usb_interface *intf, const struct usb_device_id *id,
 	}
 #endif
 
-	skb_queue_head_init(&instance->sndqueue);
+	/* initialize urbs */
 
 	for (i = 0; i < num_rcv_urbs + num_snd_urbs; i++) {
-		struct urb *urb;
 		u8 *buffer;
-		unsigned int iso_packets = 0, iso_size = 0;
 		struct usbatm_channel *channel = i < num_rcv_urbs ?
 			&instance->rx_channel : &instance->tx_channel;
+		struct urb *urb;
+		unsigned int iso_packets = usb_pipeisoc(channel->endpoint) ? channel->buf_size / channel->packet_size : 0;
 
-		if (usb_pipeisoc(channel->endpoint)) {
-			/* don't expect iso out endpoints */
-			iso_size = usb_maxpacket(instance->usb_dev, channel->endpoint, 0);
-			iso_size -= iso_size % channel->stride;	/* alignment */
-			BUG_ON(!iso_size);
-			iso_packets = (channel->buf_size - 1) / iso_size + 1;
-		}
+		UDSL_ASSERT(!usb_pipeisoc(channel->endpoint) || usb_pipein(channel->endpoint));
 
 		urb = usb_alloc_urb(iso_packets, GFP_KERNEL);
 		if (!urb) {
@@ -1132,9 +1133,8 @@ int usbatm_usb_probe(struct usb_interface *intf, const struct usb_device_id *id,
 			urb->transfer_flags = URB_ISO_ASAP;
 			urb->number_of_packets = iso_packets;
 			for (j = 0; j < iso_packets; j++) {
-				urb->iso_frame_desc[j].offset = iso_size * j;
-				urb->iso_frame_desc[j].length = min_t(int, iso_size,
-								      channel->buf_size - urb->iso_frame_desc[j].offset);
+				urb->iso_frame_desc[j].offset = channel->packet_size * j;
+				urb->iso_frame_desc[j].length = channel->packet_size;
 			}
 		}