[PATCHv2] usb/net/asix_devices: Add USBNET HG20F9 ethernet dongle

[Glen Turner <gdt@gdt.id.au>]

This USB ethernet adapter was purchased in anodyne packaging
from the computer store adjacent to linux.conf.au 2013 in
Canberra (Australia). A web search shows other recent
purchasers in Lancaster (UK) and Seattle (USA). Just like an
emergent virus, our age of e-commerce and airmail allows
underdocumented hardware to spread around the world instantly
using the vector of ridiculously low prices.

Paige Thompson, infected via eBay, discovered that the HG20F9
is a copy of the Asix 88772B; many viruses copy the RNA of
other viruses. See Paige's work at
<https://github.com/paigeadele/HG20F9>.
This patch uses her discovery to update the restructured Asix
driver in the current kernel.

Just as some viruses inhabit seemingly-healthy cells, the
HG20F9 uses the Vendor ID 0x066b assigned to Linksys Inc.
For the present there is no clash of Product ID 0x20f9.

Signed-off-by: Glen Turner <gdt@gdt.id.au>
---
David,

My apologies for the patch failing to compile. I worked off Linus' GIT tree
from a week ago, which I now realise was ignorant. Today I downloaded
<git://git.kernel.org/pub/scm/linux/kernel/git/davem/net.git>,
modified the patch to suit, compiled with a distributor's .config (ten hours
on my EeePC 901), and re-tested against a range of switches and traffic.

Thanks to Bjørn Mork for the heads-up about comment coding style. I had
copied the style used throughout asix_devices.c but one never knows where
being on the bad side of an automated tool can lead, now that the creator
of the Daleks can no longer protect us from robots with rigid notions
of the acceptable and the exterminatable.

-glen

 drivers/net/usb/asix_devices.c |   31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/drivers/net/usb/asix_devices.c b/drivers/net/usb/asix_devices.c
index 2205dbc..7097534 100644
--- a/drivers/net/usb/asix_devices.c
+++ b/drivers/net/usb/asix_devices.c
@@ -924,6 +924,29 @@ static const struct driver_info ax88178_info = {
 	.tx_fixup = asix_tx_fixup,
 };
 
+/*
+ * USBLINK 20F9 "USB 2.0 LAN" USB ethernet adapter, typically found in
+ * no-name packaging.
+ * USB device strings are:
+ *   1: Manufacturer: USBLINK
+ *   2: Product: HG20F9 USB2.0
+ *   3: Serial: 000003
+ * Appears to be compatible with Asix 88772B.
+ */
+static const struct driver_info hg20f9_info = {
+	.description = "HG20F9 USB 2.0 Ethernet",
+	.bind = ax88772_bind,
+	.unbind = ax88772_unbind,
+	.status = asix_status,
+	.link_reset = ax88772_link_reset,
+	.reset = ax88772_reset,
+	.flags = FLAG_ETHER | FLAG_FRAMING_AX | FLAG_LINK_INTR |
+	         FLAG_MULTI_PACKET,
+	.rx_fixup = asix_rx_fixup_common,
+	.tx_fixup = asix_tx_fixup,
+	.data = FLAG_EEPROM_MAC,
+};
+
 extern const struct driver_info ax88172a_info;
 
 static const struct usb_device_id	products [] = {
@@ -1063,6 +1086,14 @@ static const struct usb_device_id	products [] = {
 	/* ASIX 88172a demo board */
 	USB_DEVICE(0x0b95, 0x172a),
 	.driver_info = (unsigned long) &ax88172a_info,
+}, {
+	/*
+	 * USBLINK HG20F9 "USB 2.0 LAN"
+	 * Appears to have gazumped Linksys's manufacturer ID but
+	 * doesn't (yet) conflict with any known Linksys product.
+	 */
+	USB_DEVICE(0x066b, 0x20f9),
+	.driver_info = (unsigned long) &hg20f9_info,
 },
 	{ },		// END
 };
-- 
1.7.10.4