sierra: driver interface blacklisting

Interface blacklisting is necessary for non-serial interfaces that are handled
by a different driver. The interface blacklisting is implemented in sierra
driver per device. Each device in need of a blacklist has a static information
array kept in the driver. This array contains the interface numbers that are
blacklisted. The pointer for each blacklist array and the length
of that blacklist are 'bundled' in data structure sierra_iface_info. A pointer
to this information is set in id_table when the device is added to the id_table.

The following is summary of changes we have made to sierra.c driver in
this patch dealing with interface blacklisting support:
- Added data structure sierra_iface_info and function is_blacklisted()
to support blacklisting
- Modified sierra_probe() to handle blacklisted interfaces accordingly
- Improved comments in id_table
- Added new device in id_table with blacklist interface support

Signed-off-by: Elina Pasheva <epasheva@sierrawireless.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/usb/serial/sierra.c

@@ -37,6 +37,12 @@
 static int debug;
 static int nmea;
 
+/* Used in interface blacklisting */
+struct sierra_iface_info {
+	const u32 infolen;	/* number of interface numbers on blacklist */
+	const u8  *ifaceinfo;	/* pointer to the array holding the numbers */
+};
+
 static int sierra_set_power_state(struct usb_device *udev, __u16 swiState)
 {
 	int result;
@@ -83,6 +89,23 @@ static int sierra_calc_num_ports(struct usb_serial *serial)
 	return result;
 }
 
+static int is_blacklisted(const u8 ifnum,
+				const struct sierra_iface_info *blacklist)
+{
+	const u8  *info;
+	int i;
+
+	if (blacklist) {
+		info = blacklist->ifaceinfo;
+
+		for (i = 0; i < blacklist->infolen; i++) {
+			if (info[i] == ifnum)
+				return 1;
+		}
+	}
+	return 0;
+}
+
 static int sierra_calc_interface(struct usb_serial *serial)
 {
 	int interface;
@@ -151,9 +174,25 @@ static int sierra_probe(struct usb_serial *serial,
 	 */
 	usb_set_serial_data(serial, (void *)num_ports);
 
+	/* ifnum could have changed - by calling usb_set_interface */
+	ifnum = sierra_calc_interface(serial);
+
+	if (is_blacklisted(ifnum,
+				(struct sierra_iface_info *)id->driver_info)) {
+		dev_dbg(&serial->dev->dev,
+			"Ignoring blacklisted interface #%d\n", ifnum);
+		return -ENODEV;
+	}
+
 	return result;
 }
 
+static const u8 direct_ip_non_serial_ifaces[] = { 7, 8, 9, 10, 11 };
+static const struct sierra_iface_info direct_ip_interface_blacklist = {
+	.infolen = ARRAY_SIZE(direct_ip_non_serial_ifaces),
+	.ifaceinfo = direct_ip_non_serial_ifaces,
+};
+
 static struct usb_device_id id_table [] = {
 	{ USB_DEVICE(0x1199, 0x0017) },	/* Sierra Wireless EM5625 */
 	{ USB_DEVICE(0x1199, 0x0018) },	/* Sierra Wireless MC5720 */
@@ -186,9 +225,11 @@ static struct usb_device_id id_table [] = {
 	{ USB_DEVICE(0x1199, 0x6833) },	/* Sierra Wireless MC8781 */
 	{ USB_DEVICE(0x1199, 0x683A) },	/* Sierra Wireless MC8785 */
 	{ USB_DEVICE(0x1199, 0x683B) },	/* Sierra Wireless MC8785 Composite */
-	{ USB_DEVICE(0x1199, 0x683C) },	/* Sierra Wireless MC8790 */
-	{ USB_DEVICE(0x1199, 0x683D) },	/* Sierra Wireless MC8790 */
-	{ USB_DEVICE(0x1199, 0x683E) },	/* Sierra Wireless MC8790 */
+	/* Sierra Wireless MC8790, MC8791, MC8792 Composite */
+	{ USB_DEVICE(0x1199, 0x683C) },
+	{ USB_DEVICE(0x1199, 0x683D) },	/* Sierra Wireless MC8791 Composite */
+	/* Sierra Wireless MC8790, MC8791, MC8792 */
+	{ USB_DEVICE(0x1199, 0x683E) },
 	{ USB_DEVICE(0x1199, 0x6850) },	/* Sierra Wireless AirCard 880 */
 	{ USB_DEVICE(0x1199, 0x6851) },	/* Sierra Wireless AirCard 881 */
 	{ USB_DEVICE(0x1199, 0x6852) },	/* Sierra Wireless AirCard 880 E */
@@ -209,6 +250,10 @@ static struct usb_device_id id_table [] = {
 	{ USB_DEVICE(0x1199, 0x0112) }, /* Sierra Wireless AirCard 580 */
 	{ USB_DEVICE(0x0F3D, 0x0112) }, /* Airprime/Sierra PC 5220 */
 
+	{ USB_DEVICE(0x1199, 0x68A3), 	/* Sierra Wireless Direct IP modems */
+	  .driver_info = (kernel_ulong_t)&direct_ip_interface_blacklist
+	},
+
 	{ }
 };
 MODULE_DEVICE_TABLE(usb, id_table);