From 36cae568404a298a19a6e8a3f18641075d4cab04 Mon Sep 17 00:00:00 2001

From: Kristian Evensen <kristian.evensen@gmail.com>

Date: Thu, 13 Sep 2018 11:21:49 +0200

Subject: [PATCH] USB: serial: option: improve Quectel EP06 detection

Git-commit: 36cae568404a298a19a6e8a3f18641075d4cab04

Patch-mainline: v4.19-rc7

References: bsc#1051510

The Quectel EP06 (and EM06/EG06) LTE modem supports updating the USB

configuration, without the VID/PID or configuration number changing.

When the configuration is updated and interfaces are added/removed, the

interface numbers are updated. This causes our current code for matching

EP06 not to work as intended, as the assumption about reserved

interfaces no longer holds. If for example the diagnostic (first)

interface is removed, option will (try to) bind to the QMI interface.

This patch improves EP06 detection by replacing the current match with

two matches, and those matches check class, subclass and protocol as

well as VID and PID. The diag interface exports class, subclass and

protocol as 0xff. For the other serial interfaces, class is 0xff and

subclass and protocol are both 0x0.

The modem can export the following devices and always in this order:

diag, nmea, at, ppp. qmi and adb. This means that diag can only ever be

interface 0, and interface numbers 1-5 should be marked as reserved. The

three other serial devices can have interface numbers 0-3, but I have

not marked any interfaces as reserved. The reason is that the serial

devices are the only interfaces exported by the device where subclass

and protocol is 0x0.

QMI exports the same class, subclass and protocol values as the diag

interface. However, the two interfaces have different number of

endpoints, QMI has three and diag two. I have added a check for number

of interfaces if VID/PID matches the EP06, and we ignore the device if

number of interfaces equals three (and subclass is set).

Signed-off-by: Kristian Evensen <kristian.evensen@gmail.com>

Acked-by: Dan Williams <dcbw@redhat.com>

[ johan: drop uneeded RSVD(5) for ADB ]

Cc: stable <stable@vger.kernel.org>

Signed-off-by: Johan Hovold <johan@kernel.org>

Acked-by: Takashi Iwai <tiwai@suse.de>

---

 drivers/usb/serial/option.c |   18 ++++++++++++++++--

 1 file changed, 16 insertions(+), 2 deletions(-)

--- a/drivers/usb/serial/option.c

+++ b/drivers/usb/serial/option.c

@@ -1084,8 +1084,9 @@ static const struct usb_device_id option

 	  .driver_info = RSVD(4) },

 	{ USB_DEVICE(QUECTEL_VENDOR_ID, QUECTEL_PRODUCT_BG96),

 	  .driver_info = RSVD(4) },

-	{ USB_DEVICE(QUECTEL_VENDOR_ID, QUECTEL_PRODUCT_EP06),

-	  .driver_info = RSVD(4) | RSVD(5) },

+	{ USB_DEVICE_AND_INTERFACE_INFO(QUECTEL_VENDOR_ID, QUECTEL_PRODUCT_EP06, 0xff, 0xff, 0xff),

+	  .driver_info = RSVD(1) | RSVD(2) | RSVD(3) | RSVD(4) },

+	{ USB_DEVICE_AND_INTERFACE_INFO(QUECTEL_VENDOR_ID, QUECTEL_PRODUCT_EP06, 0xff, 0, 0) },

 	{ USB_DEVICE(CMOTECH_VENDOR_ID, CMOTECH_PRODUCT_6001) },

 	{ USB_DEVICE(CMOTECH_VENDOR_ID, CMOTECH_PRODUCT_CMU_300) },

 	{ USB_DEVICE(CMOTECH_VENDOR_ID, CMOTECH_PRODUCT_6003),

@@ -1990,6 +1991,7 @@ static int option_probe(struct usb_seria

 {

 	struct usb_interface_descriptor *iface_desc =

 				&serial->interface->cur_altsetting->desc;

+	struct usb_device_descriptor *dev_desc = &serial->dev->descriptor;

 	unsigned long device_flags = id->driver_info;

 	/* Never bind to the CD-Rom emulation interface	*/

@@ -2004,6 +2006,18 @@ static int option_probe(struct usb_seria

 	if (device_flags & RSVD(iface_desc->bInterfaceNumber))

 		return -ENODEV;

+	/*

+	 * Don't bind to the QMI device of the Quectel EP06/EG06/EM06. Class,

+	 * subclass and protocol is 0xff for both the diagnostic port and the

+	 * QMI interface, but the diagnostic port only has two endpoints (QMI

+	 * has three).

+	 */

+	if (dev_desc->idVendor == cpu_to_le16(QUECTEL_VENDOR_ID) &&

+	    dev_desc->idProduct == cpu_to_le16(QUECTEL_PRODUCT_EP06) &&

+	    iface_desc->bInterfaceSubClass && iface_desc->bNumEndpoints == 3) {

+		return -ENODEV;

+	}

+

 	/* Store the device flags so we can use them during attach. */

 	usb_set_serial_data(serial, (void *)device_flags);