1 files changed, 32 insertions, 12 deletions

diff --git a/drivers/net/usb/dm9601.c b/drivers/net/usb/dm9601.c
index c6867f926cf..14aa48fa8d7 100644
--- a/drivers/net/usb/dm9601.c
+++ b/drivers/net/usb/dm9601.c
@@ -1,5 +1,5 @@
 /*
- * Davicom DM9601 USB 1.1 10/100Mbps ethernet devices
+ * Davicom DM96xx USB 10/100Mbps ethernet devices
  *
  * Peter Korsgaard <jacmet@sunsite.dk>
  *
@@ -364,7 +364,12 @@ static int dm9601_bind(struct usbnet *dev, struct usb_interface *intf)
 	dev->net->ethtool_ops = &dm9601_ethtool_ops;
 	dev->net->hard_header_len += DM_TX_OVERHEAD;
 	dev->hard_mtu = dev->net->mtu + dev->net->hard_header_len;
-	dev->rx_urb_size = dev->net->mtu + ETH_HLEN + DM_RX_OVERHEAD;
+
+	/* dm9620/21a require room for 4 byte padding, even in dm9601
+	 * mode, so we need +1 to be able to receive full size
+	 * ethernet frames.
+	 */
+	dev->rx_urb_size = dev->net->mtu + ETH_HLEN + DM_RX_OVERHEAD + 1;
 
 	dev->mii.dev = dev->net;
 	dev->mii.mdio_read = dm9601_mdio_read;
@@ -468,7 +473,7 @@ static int dm9601_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
 static struct sk_buff *dm9601_tx_fixup(struct usbnet *dev, struct sk_buff *skb,
 				       gfp_t flags)
 {
-	int len;
+	int len, pad;
 
 	/* format:
 	   b1: packet length low
@@ -476,12 +481,23 @@ static struct sk_buff *dm9601_tx_fixup(struct usbnet *dev, struct sk_buff *skb,
 	   b3..n: packet data
 	*/
 
-	len = skb->len;
+	len = skb->len + DM_TX_OVERHEAD;
+
+	/* workaround for dm962x errata with tx fifo getting out of
+	 * sync if a USB bulk transfer retry happens right after a
+	 * packet with odd / maxpacket length by adding up to 3 bytes
+	 * padding.
+	 */
+	while ((len & 1) || !(len % dev->maxpacket))
+		len++;
 
-	if (skb_headroom(skb) < DM_TX_OVERHEAD) {
+	len -= DM_TX_OVERHEAD; /* hw header doesn't count as part of length */
+	pad = len - skb->len;
+
+	if (skb_headroom(skb) < DM_TX_OVERHEAD || skb_tailroom(skb) < pad) {
 		struct sk_buff *skb2;
 
-		skb2 = skb_copy_expand(skb, DM_TX_OVERHEAD, 0, flags);
+		skb2 = skb_copy_expand(skb, DM_TX_OVERHEAD, pad, flags);
 		dev_kfree_skb_any(skb);
 		skb = skb2;
 		if (!skb)
@@ -490,10 +506,10 @@ static struct sk_buff *dm9601_tx_fixup(struct usbnet *dev, struct sk_buff *skb,
 
 	__skb_push(skb, DM_TX_OVERHEAD);
 
-	/* usbnet adds padding if length is a multiple of packet size
-	   if so, adjust length value in header */
-	if ((skb->len % dev->maxpacket) == 0)
-		len++;
+	if (pad) {
+		memset(skb->data + skb->len, 0, pad);
+		__skb_put(skb, pad);
+	}
 
 	skb->data[0] = len;
 	skb->data[1] = len >> 8;
@@ -543,7 +559,7 @@ static int dm9601_link_reset(struct usbnet *dev)
 }
 
 static const struct driver_info dm9601_info = {
-	.description	= "Davicom DM9601 USB Ethernet",
+	.description	= "Davicom DM96xx USB 10/100 Ethernet",
 	.flags		= FLAG_ETHER | FLAG_LINK_INTR,
 	.bind		= dm9601_bind,
 	.rx_fixup	= dm9601_rx_fixup,
@@ -594,6 +610,10 @@ static const struct usb_device_id products[] = {
 	 USB_DEVICE(0x0a46, 0x9620),	/* DM9620 USB to Fast Ethernet Adapter */
 	 .driver_info = (unsigned long)&dm9601_info,
 	 },
+	{
+	 USB_DEVICE(0x0a46, 0x9621),	/* DM9621A USB to Fast Ethernet Adapter */
+	 .driver_info = (unsigned long)&dm9601_info,
+	},
 	{},			// END
 };
 
@@ -612,5 +632,5 @@ static struct usb_driver dm9601_driver = {
 module_usb_driver(dm9601_driver);
 
 MODULE_AUTHOR("Peter Korsgaard <jacmet@sunsite.dk>");
-MODULE_DESCRIPTION("Davicom DM9601 USB 1.1 ethernet devices");
+MODULE_DESCRIPTION("Davicom DM96xx USB 10/100 ethernet devices");
 MODULE_LICENSE("GPL");