[PATCH] USB: better usbnet zaurus/mdlm/... fix

This is a somewhat more comprehensive fix for the problem of devices
like the newer Zaurii ... or in this case some Motorola cell phones.

To recap, the problem's root cause is that these devices aren't using
standard USB class specifications for their network links, and so far
we've had to add lots of device-specific driver entries.  The vendor
fix abuses the CDC MDLM descriptors (they _could_ have conformed to
the spec, but didn't) and defines a "Belcarra firmware" pseudo-class.

This patch recognizes that pseudo-class by the GUIDs in those descriptors,
and handles the devices that just use the Zaurus framing.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/net/usbnet.c

 /*
  * USB Networking Links
- * Copyright (C) 2000-2003 by David Brownell <dbrownell@users.sourceforge.net>
+ * Copyright (C) 2000-2005 by David Brownell <dbrownell@users.sourceforge.net>
  * Copyright (C) 2002 Pavel Machek <pavel@ucw.cz>
  * Copyright (C) 2003-2005 David Hollis <dhollis@davehollis.com>
  * Copyright (C) 2005 Phil Chang <pchang23@sbcglobal.net>
@@ -2657,7 +2657,7 @@ static const struct driver_info	blob_info = {
  * All known Zaurii lie about their standards conformance.  Most lie by
  * saying they support CDC Ethernet.  Some lie and say they support CDC
  * MDLM (as if for access to cell phone modems).  Someone, please beat 
- * on Sharp for a while with a cluestick.
+ * on Sharp (and other such vendors) for a while with a cluestick.
  *
  *-------------------------------------------------------------------------*/
 
@@ -2710,13 +2710,6 @@ static const struct driver_info	zaurus_pxa_info = {
 };
 #define	ZAURUS_PXA_INFO		((unsigned long)&zaurus_pxa_info)
 
-static const struct driver_info	zaurus_pxa_mdlm_info = {
-	.description =	"Sharp Zaurus, PXA-255 based",
-	.flags =	FLAG_FRAMING_Z,
-	.check_connect = always_connected,
-	.tx_fixup = 	zaurus_tx_fixup,
-};
-
 static const struct driver_info	olympus_mxl_info = {
 	.description =	"Olympus R1000",
 	.flags =	FLAG_FRAMING_Z,
@@ -2727,6 +2720,133 @@ static const struct driver_info	olympus_mxl_info = {
 };
 #define	OLYMPUS_MXL_INFO	((unsigned long)&olympus_mxl_info)
 
+
+/* Some more recent products using Lineo/Belcarra code will wrongly claim
+ * CDC MDLM conformance.  They aren't conformant:  data endpoints live
+ * in the control interface, there's no data interface, and it's not used
+ * to talk to a cell phone radio.  But at least we can detect these two
+ * pseudo-classes, rather than growing this product list with entries for
+ * each new nonconformant product (sigh).
+ */
+static const u8 safe_guid[16] = {
+	0x5d, 0x34, 0xcf, 0x66, 0x11, 0x18, 0x11, 0xd6,
+	0xa2, 0x1a, 0x00, 0x01, 0x02, 0xca, 0x9a, 0x7f,
+};
+static const u8 blan_guid[16] = {
+	0x74, 0xf0, 0x3d, 0xbd, 0x1e, 0xc1, 0x44, 0x70,
+	0xa3, 0x67, 0x71, 0x34, 0xc9, 0xf5, 0x54, 0x37,
+};
+
+static int blan_mdlm_bind (struct usbnet *dev, struct usb_interface *intf)
+{
+	u8				*buf = intf->cur_altsetting->extra;
+	int				len = intf->cur_altsetting->extralen;
+	struct usb_cdc_mdlm_desc	*desc = NULL;
+	struct usb_cdc_mdlm_detail_desc	*detail = NULL;
+
+	while (len > 3) {
+		if (buf [1] != USB_DT_CS_INTERFACE)
+			goto next_desc;
+
+		/* use bDescriptorSubType, and just verify that we get a
+		 * "BLAN" (or "SAFE") descriptor.
+		 */
+		switch (buf [2]) {
+		case USB_CDC_MDLM_TYPE:
+			if (desc) {
+				dev_dbg (&intf->dev, "extra MDLM\n");
+				goto bad_desc;
+			}
+			desc = (void *) buf;
+			if (desc->bLength != sizeof *desc) {
+				dev_dbg (&intf->dev, "MDLM len %u\n",
+					desc->bLength);
+				goto bad_desc;
+			}
+			/* expect bcdVersion 1.0, ignore */
+			if (memcmp(&desc->bGUID, blan_guid, 16)
+				    || memcmp(&desc->bGUID, blan_guid, 16) ) {
+				/* hey, this one might _really_ be MDLM! */
+				dev_dbg (&intf->dev, "MDLM guid\n");
+				goto bad_desc;
+			}
+			break;
+		case USB_CDC_MDLM_DETAIL_TYPE:
+			if (detail) {
+				dev_dbg (&intf->dev, "extra MDLM detail\n");
+				goto bad_desc;
+			}
+			detail = (void *) buf;
+			switch (detail->bGuidDescriptorType) {
+			case 0:			/* "SAFE" */
+				if (detail->bLength != (sizeof *detail + 2))
+					goto bad_detail;
+				break;
+			case 1:			/* "BLAN" */
+				if (detail->bLength != (sizeof *detail + 3))
+					goto bad_detail;
+				break;
+			default:
+				goto bad_detail;
+			}
+
+			/* assuming we either noticed BLAN already, or will
+			 * find it soon, there are some data bytes here:
+			 *  - bmNetworkCapabilities (unused)
+			 *  - bmDataCapabilities (bits, see below)
+			 *  - bPad (ignored, for PADAFTER -- BLAN-only)
+			 * bits are:
+			 *  - 0x01 -- Zaurus framing (add CRC)
+			 *  - 0x02 -- PADBEFORE
+			 *  - 0x04 -- PADAFTER
+			 *  - 0x08 -- "fermat" packet mangling (for hw bugs)
+			 */
+			if (detail->bDetailData[1] != 0x01) {
+				/* bmDataCapabilites == 0 would be fine too,
+				 * but framing is minidriver-coupled for now.
+				 */
+bad_detail:
+				dev_dbg (&intf->dev,
+						"bad MDLM detail, %d %d %d\n",
+						detail->bLength,
+						detail->bDetailData[0],
+						detail->bDetailData[2]);
+				goto bad_desc;
+			}
+			break;
+		}
+next_desc:
+		len -= buf [0];	/* bLength */
+		buf += buf [0];
+	}
+
+	if (!desc || !detail) {
+		dev_dbg (&intf->dev, "missing cdc mdlm %s%sdescriptor\n",
+			desc ? "" : "func ",
+			detail ? "" : "detail ");
+		goto bad_desc;
+	}
+
+	/* There's probably a CDC Ethernet descriptor there, but we can't
+	 * rely on the Ethernet address it provides since not all vendors
+	 * bother to make it unique.  Likewise there's no point in tracking
+	 * of the CDC event notifications.
+	 */
+	return get_endpoints (dev, intf);
+
+bad_desc:
+	dev_info (&dev->udev->dev, "unsupported MDLM descriptors\n");
+	return -ENODEV;
+}
+
+static const struct driver_info	bogus_mdlm_info = {
+	.description =	"pseudo-MDLM (BLAN) device",
+	.flags =	FLAG_FRAMING_Z,
+	.check_connect = always_connected,
+	.tx_fixup = 	zaurus_tx_fixup,
+	.bind =		blan_mdlm_bind,
+};
+
 #else
 
 /* blacklist all those devices */
@@ -4029,30 +4149,14 @@ static const struct usb_device_id	products [] = {
 },
 
 #ifdef	CONFIG_USB_ZAURUS
-	/* at least some (reports vary) PXA units have very different
-	 * lies about their standards support:  they claim to be cell
-	 * phones giving direct radio access (which they aren't).
+	/* At least some (reports vary) PXA units have very different lies
+	 * about their standards support:  they claim to be cell phones with
+	 * direct access to their radios.  (They don't conform to CDC MDLM.)
 	 */
 {
-	.match_flags    =   USB_DEVICE_ID_MATCH_INT_INFO
-		 | USB_DEVICE_ID_MATCH_DEVICE,
-	.idVendor               = 0x04DD,
-	/* Sharp ROM v1.32 */
-	.idProduct		= 0x8006,	/* SL-5600 */
-	.bInterfaceClass	= USB_CLASS_COMM,
-	.bInterfaceSubClass	= USB_CDC_SUBCLASS_MDLM,
-	.bInterfaceProtocol	= USB_CDC_PROTO_NONE,
-	.driver_info 		= (unsigned long) &zaurus_pxa_mdlm_info,
-}, {
-	.match_flags    =   USB_DEVICE_ID_MATCH_INT_INFO
-		 | USB_DEVICE_ID_MATCH_DEVICE,
-	.idVendor               = 0x04DD,
-	/* reported with some C860 units */
-	.idProduct              = 0x9031,	/* C-860 */
-	.bInterfaceClass	= USB_CLASS_COMM,
-	.bInterfaceSubClass	= USB_CDC_SUBCLASS_MDLM,
-	.bInterfaceProtocol	= USB_CDC_PROTO_NONE,
-	.driver_info 		= (unsigned long) &zaurus_pxa_mdlm_info,
+	USB_INTERFACE_INFO (USB_CLASS_COMM, USB_CDC_SUBCLASS_MDLM,
+			USB_CDC_PROTO_NONE),
+	.driver_info = (unsigned long) &bogus_mdlm_info,
 },
 #endif