drivers/net/usb/qmi_wwan.c - kernel/msm-4.19 - Gitiles

 /*
  * Copyright (c) 2012  Bjørn Mork <bjorn@mork.no>
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
  * version 2 as published by the Free Software Foundation.
  */

 #include <linux/module.h>
 #include <linux/netdevice.h>
 #include <linux/ethtool.h>
 #include <linux/mii.h>
 #include <linux/usb.h>
 #include <linux/usb/cdc.h>
 #include <linux/usb/usbnet.h>
 #include <linux/usb/cdc-wdm.h>

 /* The name of the CDC Device Management driver */
 #define DM_DRIVER "cdc_wdm"

 /*
  * This driver supports wwan (3G/LTE/?) devices using a vendor
  * specific management protocol called Qualcomm MSM Interface (QMI) -
  * in addition to the more common AT commands over serial interface
  * management
  *
  * QMI is wrapped in CDC, using CDC encapsulated commands on the
  * control ("master") interface of a two-interface CDC Union
  * resembling standard CDC ECM.  The devices do not use the control
  * interface for any other CDC messages.  Most likely because the
  * management protocol is used in place of the standard CDC
  * notifications NOTIFY_NETWORK_CONNECTION and NOTIFY_SPEED_CHANGE
  *
  * Handling a protocol like QMI is out of the scope for any driver.
  * It can be exported as a character device using the cdc-wdm driver,
  * which will enable userspace applications ("modem managers") to
  * handle it.  This may be required to use the network interface
  * provided by the driver.
  *
  * These devices may alternatively/additionally be configured using AT
  * commands on any of the serial interfaces driven by the option driver
  *
  * This driver binds only to the data ("slave") interface to enable
  * the cdc-wdm driver to bind to the control interface.  It still
  * parses the CDC functional descriptors on the control interface to
  *  a) verify that this is indeed a handled interface (CDC Union
  *     header lists it as slave)
  *  b) get MAC address and other ethernet config from the CDC Ethernet
  *     header
  *  c) enable user bind requests against the control interface, which
  *     is the common way to bind to CDC Ethernet Control Model type
  *     interfaces
  *  d) provide a hint to the user about which interface is the
  *     corresponding management interface
  */

 static int qmi_wwan_bind(struct usbnet *dev, struct usb_interface *intf)
 {
 	int status = -1;
 	struct usb_interface *control = NULL;
 	u8 *buf = intf->cur_altsetting->extra;
 	int len = intf->cur_altsetting->extralen;
 	struct usb_interface_descriptor *desc = &intf->cur_altsetting->desc;
 	struct usb_cdc_union_desc *cdc_union = NULL;
 	struct usb_cdc_ether_desc *cdc_ether = NULL;
 	u32 required = 1 << USB_CDC_HEADER_TYPE | 1 << USB_CDC_UNION_TYPE;
 	u32 found = 0;
 	atomic_t *pmcount = (void *)&dev->data[1];

 	atomic_set(pmcount, 0);

 	/*
 	 * assume a data interface has no additional descriptors and
 	 * that the control and data interface are numbered
 	 * consecutively - this holds for the Huawei device at least
 	 */
 	if (len == 0 && desc->bInterfaceNumber > 0) {
 		control = usb_ifnum_to_if(dev->udev, desc->bInterfaceNumber - 1);
 		if (!control)
 			goto err;

 		buf = control->cur_altsetting->extra;
 		len = control->cur_altsetting->extralen;
 		dev_dbg(&intf->dev, "guessing \"control\" => %s, \"data\" => this\n",
 			dev_name(&control->dev));
 	}

 	while (len > 3) {
 		struct usb_descriptor_header *h = (void *)buf;

 		/* ignore any misplaced descriptors */
 		if (h->bDescriptorType != USB_DT_CS_INTERFACE)
 			goto next_desc;

 		/* buf[2] is CDC descriptor subtype */
 		switch (buf[2]) {
 		case USB_CDC_HEADER_TYPE:
 			if (found & 1 << USB_CDC_HEADER_TYPE) {
 				dev_dbg(&intf->dev, "extra CDC header\n");
 				goto err;
 			}
 			if (h->bLength != sizeof(struct usb_cdc_header_desc)) {
 				dev_dbg(&intf->dev, "CDC header len %u\n", h->bLength);
 				goto err;
 			}
 			break;
 		case USB_CDC_UNION_TYPE:
 			if (found & 1 << USB_CDC_UNION_TYPE) {
 				dev_dbg(&intf->dev, "extra CDC union\n");
 				goto err;
 			}
 			if (h->bLength != sizeof(struct usb_cdc_union_desc)) {
 				dev_dbg(&intf->dev, "CDC union len %u\n", h->bLength);
 				goto err;
 			}
 			cdc_union = (struct usb_cdc_union_desc *)buf;
 			break;
 		case USB_CDC_ETHERNET_TYPE:
 			if (found & 1 << USB_CDC_ETHERNET_TYPE) {
 				dev_dbg(&intf->dev, "extra CDC ether\n");
 				goto err;
 			}
 			if (h->bLength != sizeof(struct usb_cdc_ether_desc)) {
 				dev_dbg(&intf->dev, "CDC ether len %u\n",  h->bLength);
 				goto err;
 			}
 			cdc_ether = (struct usb_cdc_ether_desc *)buf;
 			break;
 		}

 		/*
 		 * Remember which CDC functional descriptors we've seen.  Works
 		 * for all types we care about, of which USB_CDC_ETHERNET_TYPE
 		 * (0x0f) is the highest numbered
 		 */
 		if (buf[2] < 32)
 			found |= 1 << buf[2];

 next_desc:
 		len -= h->bLength;
 		buf += h->bLength;
 	}

 	/* did we find all the required ones? */
 	if ((found & required) != required) {
 		dev_err(&intf->dev, "CDC functional descriptors missing\n");
 		goto err;
 	}

 	/* give the user a helpful hint if trying to bind to the wrong interface */
 	if (cdc_union && desc->bInterfaceNumber == cdc_union->bMasterInterface0) {
 		dev_err(&intf->dev, "leaving \"control\" interface for " DM_DRIVER " - try binding to %s instead!\n",
 			dev_name(&usb_ifnum_to_if(dev->udev, cdc_union->bSlaveInterface0)->dev));
 		goto err;
 	}

 	/* errors aren't fatal - we can live with the dynamic address */
 	if (cdc_ether) {
 		dev->hard_mtu = le16_to_cpu(cdc_ether->wMaxSegmentSize);
 		usbnet_get_ethernet_addr(dev, cdc_ether->iMACAddress);
 	}

 	/* success! point the user to the management interface */
 	if (control)
 		dev_info(&intf->dev, "Use \"" DM_DRIVER "\" for QMI interface %s\n",
 			dev_name(&control->dev));

 	/* XXX: add a sysfs symlink somewhere to help management applications find it? */

 	/* collect bulk endpoints now that we know intf == "data" interface */
 	status = usbnet_get_endpoints(dev, intf);

 err:
 	return status;
 }

 /* using a counter to merge subdriver requests with our own into a combined state */
 static int qmi_wwan_manage_power(struct usbnet *dev, int on)
 {
 	atomic_t *pmcount = (void *)&dev->data[1];
 	int rv = 0;

 	dev_dbg(&dev->intf->dev, "%s() pmcount=%d, on=%d\n", __func__, atomic_read(pmcount), on);

 	if ((on && atomic_add_return(1, pmcount) == 1) || (!on && atomic_dec_and_test(pmcount))) {
 		/* need autopm_get/put here to ensure the usbcore sees the new value */
 		rv = usb_autopm_get_interface(dev->intf);
 		if (rv < 0)
 			goto err;
 		dev->intf->needs_remote_wakeup = on;
 		usb_autopm_put_interface(dev->intf);
 	}
 err:
 	return rv;
 }

 static int qmi_wwan_cdc_wdm_manage_power(struct usb_interface *intf, int on)
 {
 	struct usbnet *dev = usb_get_intfdata(intf);
 	return qmi_wwan_manage_power(dev, on);
 }

 /* Some devices combine the "control" and "data" functions into a
  * single interface with all three endpoints: interrupt + bulk in and
  * out
  *
  * Setting up cdc-wdm as a subdriver owning the interrupt endpoint
  * will let it provide userspace access to the encapsulated QMI
  * protocol without interfering with the usbnet operations.
   */
 static int qmi_wwan_bind_shared(struct usbnet *dev, struct usb_interface *intf)
 {
 	int rv;
 	struct usb_driver *subdriver = NULL;
 	atomic_t *pmcount = (void *)&dev->data[1];

 	/* ZTE makes devices where the interface descriptors and endpoint
 	 * configurations of two or more interfaces are identical, even
 	 * though the functions are completely different.  If set, then
 	 * driver_info->data is a bitmap of acceptable interface numbers
 	 * allowing us to bind to one such interface without binding to
 	 * all of them
 	 */
 	if (dev->driver_info->data &&
 	    !test_bit(intf->cur_altsetting->desc.bInterfaceNumber, &dev->driver_info->data)) {
 		dev_info(&intf->dev, "not on our whitelist - ignored");
 		rv = -ENODEV;
 		goto err;
 	}

 	atomic_set(pmcount, 0);

 	/* collect all three endpoints */
 	rv = usbnet_get_endpoints(dev, intf);
 	if (rv < 0)
 		goto err;

 	/* require interrupt endpoint for subdriver */
 	if (!dev->status) {
 		rv = -EINVAL;
 		goto err;
 	}

 	subdriver = usb_cdc_wdm_register(intf, &dev->status->desc, 512, &qmi_wwan_cdc_wdm_manage_power);
 	if (IS_ERR(subdriver)) {
 		rv = PTR_ERR(subdriver);
 		goto err;
 	}

 	/* can't let usbnet use the interrupt endpoint */
 	dev->status = NULL;

 	/* save subdriver struct for suspend/resume wrappers */
 	dev->data[0] = (unsigned long)subdriver;

 err:
 	return rv;
 }

 /* Gobi devices uses identical class/protocol codes for all interfaces regardless
  * of function. Some of these are CDC ACM like and have the exact same endpoints
  * we are looking for. This leaves two possible strategies for identifying the
  * correct interface:
  *   a) hardcoding interface number, or
  *   b) use the fact that the wwan interface is the only one lacking additional
  *      (CDC functional) descriptors
  *
  * Let's see if we can get away with the generic b) solution.
  */
 static int qmi_wwan_bind_gobi(struct usbnet *dev, struct usb_interface *intf)
 {
 	int rv = -EINVAL;

 	/* ignore any interface with additional descriptors */
 	if (intf->cur_altsetting->extralen)
 		goto err;

 	rv = qmi_wwan_bind_shared(dev, intf);
 err:
 	return rv;
 }

 static void qmi_wwan_unbind_shared(struct usbnet *dev, struct usb_interface *intf)
 {
 	struct usb_driver *subdriver = (void *)dev->data[0];

 	if (subdriver && subdriver->disconnect)
 		subdriver->disconnect(intf);

 	dev->data[0] = (unsigned long)NULL;
 }

 /* suspend/resume wrappers calling both usbnet and the cdc-wdm
  * subdriver if present.
  *
  * NOTE: cdc-wdm also supports pre/post_reset, but we cannot provide
  * wrappers for those without adding usbnet reset support first.
  */
 static int qmi_wwan_suspend(struct usb_interface *intf, pm_message_t message)
 {
 	struct usbnet *dev = usb_get_intfdata(intf);
 	struct usb_driver *subdriver = (void *)dev->data[0];
 	int ret;

 	ret = usbnet_suspend(intf, message);
 	if (ret < 0)
 		goto err;

 	if (subdriver && subdriver->suspend)
 		ret = subdriver->suspend(intf, message);
 	if (ret < 0)
 		usbnet_resume(intf);
 err:
 	return ret;
 }

 static int qmi_wwan_resume(struct usb_interface *intf)
 {
 	struct usbnet *dev = usb_get_intfdata(intf);
 	struct usb_driver *subdriver = (void *)dev->data[0];
 	int ret = 0;

 	if (subdriver && subdriver->resume)
 		ret = subdriver->resume(intf);
 	if (ret < 0)
 		goto err;
 	ret = usbnet_resume(intf);
 	if (ret < 0 && subdriver && subdriver->resume && subdriver->suspend)
 		subdriver->suspend(intf, PMSG_SUSPEND);
 err:
 	return ret;
 }


 static const struct driver_info	qmi_wwan_info = {
 	.description	= "QMI speaking wwan device",
 	.flags		= FLAG_WWAN,
 	.bind		= qmi_wwan_bind,
 	.manage_power	= qmi_wwan_manage_power,
 };

 static const struct driver_info	qmi_wwan_shared = {
 	.description	= "QMI speaking wwan device with combined interface",
 	.flags		= FLAG_WWAN,
 	.bind		= qmi_wwan_bind_shared,
 	.unbind		= qmi_wwan_unbind_shared,
 	.manage_power	= qmi_wwan_manage_power,
 };

 static const struct driver_info	qmi_wwan_gobi = {
 	.description	= "Qualcomm Gobi wwan/QMI device",
 	.flags		= FLAG_WWAN,
 	.bind		= qmi_wwan_bind_gobi,
 	.unbind		= qmi_wwan_unbind_shared,
 	.manage_power	= qmi_wwan_manage_power,
 };

 /* ZTE suck at making USB descriptors */
 static const struct driver_info	qmi_wwan_force_int4 = {
 	.description	= "Qualcomm Gobi wwan/QMI device",
 	.flags		= FLAG_WWAN,
 	.bind		= qmi_wwan_bind_gobi,
 	.unbind		= qmi_wwan_unbind_shared,
 	.manage_power	= qmi_wwan_manage_power,
 	.data		= BIT(4), /* interface whitelist bitmap */
 };


 #define HUAWEI_VENDOR_ID	0x12D1
 #define QMI_GOBI_DEVICE(vend, prod) \
 	USB_DEVICE(vend, prod), \
 	.driver_info = (unsigned long)&qmi_wwan_gobi

 static const struct usb_device_id products[] = {
 	{	/* Huawei E392, E398 and possibly others sharing both device id and more... */
 		.match_flags        = USB_DEVICE_ID_MATCH_VENDOR | USB_DEVICE_ID_MATCH_INT_INFO,
 		.idVendor           = HUAWEI_VENDOR_ID,
 		.bInterfaceClass    = USB_CLASS_VENDOR_SPEC,
 		.bInterfaceSubClass = 1,
 		.bInterfaceProtocol = 8, /* NOTE: This is the *slave* interface of the CDC Union! */
 		.driver_info        = (unsigned long)&qmi_wwan_info,
 	},
 	{	/* Huawei E392, E398 and possibly others in "Windows mode"
 		 * using a combined control and data interface without any CDC
 		 * functional descriptors
 		 */
 		.match_flags        = USB_DEVICE_ID_MATCH_VENDOR | USB_DEVICE_ID_MATCH_INT_INFO,
 		.idVendor           = HUAWEI_VENDOR_ID,
 		.bInterfaceClass    = USB_CLASS_VENDOR_SPEC,
 		.bInterfaceSubClass = 1,
 		.bInterfaceProtocol = 17,
 		.driver_info        = (unsigned long)&qmi_wwan_shared,
 	},
 	{	/* Pantech UML290 */
 		.match_flags	    = USB_DEVICE_ID_MATCH_DEVICE | USB_DEVICE_ID_MATCH_INT_INFO,
 		.idVendor           = 0x106c,
 		.idProduct          = 0x3718,
 		.bInterfaceClass    = 0xff,
 		.bInterfaceSubClass = 0xf0,
 		.bInterfaceProtocol = 0xff,
 		.driver_info        = (unsigned long)&qmi_wwan_shared,
 	},
 	{	/* ZTE MF820D */
 		.match_flags	    = USB_DEVICE_ID_MATCH_DEVICE | USB_DEVICE_ID_MATCH_INT_INFO,
 		.idVendor           = 0x19d2,
 		.idProduct          = 0x0167,
 		.bInterfaceClass    = 0xff,
 		.bInterfaceSubClass = 0xff,
 		.bInterfaceProtocol = 0xff,
 		.driver_info        = (unsigned long)&qmi_wwan_force_int4,
 	},
 	{	/* ZTE (Vodafone) K3565-Z */
 		.match_flags	    = USB_DEVICE_ID_MATCH_DEVICE | USB_DEVICE_ID_MATCH_INT_INFO,
 		.idVendor           = 0x19d2,
 		.idProduct          = 0x0063,
 		.bInterfaceClass    = 0xff,
 		.bInterfaceSubClass = 0xff,
 		.bInterfaceProtocol = 0xff,
 		.driver_info        = (unsigned long)&qmi_wwan_force_int4,
 	},
 	{	/* ZTE (Vodafone) K3570-Z */
 		.match_flags	    = USB_DEVICE_ID_MATCH_DEVICE | USB_DEVICE_ID_MATCH_INT_INFO,
 		.idVendor           = 0x19d2,
 		.idProduct          = 0x1008,
 		.bInterfaceClass    = 0xff,
 		.bInterfaceSubClass = 0xff,
 		.bInterfaceProtocol = 0xff,
 		.driver_info        = (unsigned long)&qmi_wwan_force_int4,
 	},
 	{	/* ZTE (Vodafone) K3571-Z */
 		.match_flags	    = USB_DEVICE_ID_MATCH_DEVICE | USB_DEVICE_ID_MATCH_INT_INFO,
 		.idVendor           = 0x19d2,
 		.idProduct          = 0x1010,
 		.bInterfaceClass    = 0xff,
 		.bInterfaceSubClass = 0xff,
 		.bInterfaceProtocol = 0xff,
 		.driver_info        = (unsigned long)&qmi_wwan_force_int4,
 	},
 	{	/* ZTE (Vodafone) K4505-Z */
 		.match_flags	    = USB_DEVICE_ID_MATCH_DEVICE | USB_DEVICE_ID_MATCH_INT_INFO,
 		.idVendor           = 0x19d2,
 		.idProduct          = 0x0104,
 		.bInterfaceClass    = 0xff,
 		.bInterfaceSubClass = 0xff,
 		.bInterfaceProtocol = 0xff,
 		.driver_info        = (unsigned long)&qmi_wwan_force_int4,
 	},
 	{QMI_GOBI_DEVICE(0x05c6, 0x9212)},	/* Acer Gobi Modem Device */
 	{QMI_GOBI_DEVICE(0x03f0, 0x1f1d)},	/* HP un2400 Gobi Modem Device */
 	{QMI_GOBI_DEVICE(0x03f0, 0x371d)},	/* HP un2430 Mobile Broadband Module */
 	{QMI_GOBI_DEVICE(0x04da, 0x250d)},	/* Panasonic Gobi Modem device */
 	{QMI_GOBI_DEVICE(0x413c, 0x8172)},	/* Dell Gobi Modem device */
 	{QMI_GOBI_DEVICE(0x1410, 0xa001)},	/* Novatel Gobi Modem device */
 	{QMI_GOBI_DEVICE(0x0b05, 0x1776)},	/* Asus Gobi Modem device */
 	{QMI_GOBI_DEVICE(0x19d2, 0xfff3)},	/* ONDA Gobi Modem device */
 	{QMI_GOBI_DEVICE(0x05c6, 0x9001)},	/* Generic Gobi Modem device */
 	{QMI_GOBI_DEVICE(0x05c6, 0x9002)},	/* Generic Gobi Modem device */
 	{QMI_GOBI_DEVICE(0x05c6, 0x9202)},	/* Generic Gobi Modem device */
 	{QMI_GOBI_DEVICE(0x05c6, 0x9203)},	/* Generic Gobi Modem device */
 	{QMI_GOBI_DEVICE(0x05c6, 0x9222)},	/* Generic Gobi Modem device */
 	{QMI_GOBI_DEVICE(0x05c6, 0x9009)},	/* Generic Gobi Modem device */
 	{QMI_GOBI_DEVICE(0x413c, 0x8186)},	/* Dell Gobi 2000 Modem device (N0218, VU936) */
 	{QMI_GOBI_DEVICE(0x05c6, 0x920b)},	/* Generic Gobi 2000 Modem device */
 	{QMI_GOBI_DEVICE(0x05c6, 0x9225)},	/* Sony Gobi 2000 Modem device (N0279, VU730) */
 	{QMI_GOBI_DEVICE(0x05c6, 0x9245)},	/* Samsung Gobi 2000 Modem device (VL176) */
 	{QMI_GOBI_DEVICE(0x03f0, 0x251d)},	/* HP Gobi 2000 Modem device (VP412) */
 	{QMI_GOBI_DEVICE(0x05c6, 0x9215)},	/* Acer Gobi 2000 Modem device (VP413) */
 	{QMI_GOBI_DEVICE(0x05c6, 0x9265)},	/* Asus Gobi 2000 Modem device (VR305) */
 	{QMI_GOBI_DEVICE(0x05c6, 0x9235)},	/* Top Global Gobi 2000 Modem device (VR306) */
 	{QMI_GOBI_DEVICE(0x05c6, 0x9275)},	/* iRex Technologies Gobi 2000 Modem device (VR307) */
 	{QMI_GOBI_DEVICE(0x1199, 0x9001)},	/* Sierra Wireless Gobi 2000 Modem device (VT773) */
 	{QMI_GOBI_DEVICE(0x1199, 0x9002)},	/* Sierra Wireless Gobi 2000 Modem device (VT773) */
 	{QMI_GOBI_DEVICE(0x1199, 0x9003)},	/* Sierra Wireless Gobi 2000 Modem device (VT773) */
 	{QMI_GOBI_DEVICE(0x1199, 0x9004)},	/* Sierra Wireless Gobi 2000 Modem device (VT773) */
 	{QMI_GOBI_DEVICE(0x1199, 0x9005)},	/* Sierra Wireless Gobi 2000 Modem device (VT773) */
 	{QMI_GOBI_DEVICE(0x1199, 0x9006)},	/* Sierra Wireless Gobi 2000 Modem device (VT773) */
 	{QMI_GOBI_DEVICE(0x1199, 0x9007)},	/* Sierra Wireless Gobi 2000 Modem device (VT773) */
 	{QMI_GOBI_DEVICE(0x1199, 0x9008)},	/* Sierra Wireless Gobi 2000 Modem device (VT773) */
 	{QMI_GOBI_DEVICE(0x1199, 0x9009)},	/* Sierra Wireless Gobi 2000 Modem device (VT773) */
 	{QMI_GOBI_DEVICE(0x1199, 0x900a)},	/* Sierra Wireless Gobi 2000 Modem device (VT773) */
 	{QMI_GOBI_DEVICE(0x1199, 0x9011)},	/* Sierra Wireless Gobi 2000 Modem device (MC8305) */
 	{QMI_GOBI_DEVICE(0x16d8, 0x8002)},	/* CMDTech Gobi 2000 Modem device (VU922) */
 	{QMI_GOBI_DEVICE(0x05c6, 0x9205)},	/* Gobi 2000 Modem device */
 	{QMI_GOBI_DEVICE(0x1199, 0x9013)},	/* Sierra Wireless Gobi 3000 Modem device (MC8355) */
 	{ }					/* END */
 };
 MODULE_DEVICE_TABLE(usb, products);

 static struct usb_driver qmi_wwan_driver = {
 	.name		      = "qmi_wwan",
 	.id_table	      = products,
 	.probe		      =	usbnet_probe,
 	.disconnect	      = usbnet_disconnect,
 	.suspend	      = qmi_wwan_suspend,
 	.resume		      =	qmi_wwan_resume,
 	.reset_resume         = qmi_wwan_resume,
 	.supports_autosuspend = 1,
 };

 static int __init qmi_wwan_init(void)
 {
 	return usb_register(&qmi_wwan_driver);
 }
 module_init(qmi_wwan_init);

 static void __exit qmi_wwan_exit(void)
 {
 	usb_deregister(&qmi_wwan_driver);
 }
 module_exit(qmi_wwan_exit);

 MODULE_AUTHOR("Bjørn Mork <bjorn@mork.no>");
 MODULE_DESCRIPTION("Qualcomm MSM Interface (QMI) WWAN driver");
 MODULE_LICENSE("GPL");
	/*
	* Copyright (c) 2012 Bjørn Mork <bjorn@mork.no>
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License
	* version 2 as published by the Free Software Foundation.
	*/

	#include <linux/module.h>
	#include <linux/netdevice.h>
	#include <linux/ethtool.h>
	#include <linux/mii.h>
	#include <linux/usb.h>
	#include <linux/usb/cdc.h>
	#include <linux/usb/usbnet.h>
	#include <linux/usb/cdc-wdm.h>

	/* The name of the CDC Device Management driver */
	#define DM_DRIVER "cdc_wdm"

	/*
	* This driver supports wwan (3G/LTE/?) devices using a vendor
	* specific management protocol called Qualcomm MSM Interface (QMI) -
	* in addition to the more common AT commands over serial interface
	* management
	*
	* QMI is wrapped in CDC, using CDC encapsulated commands on the
	* control ("master") interface of a two-interface CDC Union
	* resembling standard CDC ECM. The devices do not use the control
	* interface for any other CDC messages. Most likely because the
	* management protocol is used in place of the standard CDC
	* notifications NOTIFY_NETWORK_CONNECTION and NOTIFY_SPEED_CHANGE
	*
	* Handling a protocol like QMI is out of the scope for any driver.
	* It can be exported as a character device using the cdc-wdm driver,
	* which will enable userspace applications ("modem managers") to
	* handle it. This may be required to use the network interface
	* provided by the driver.
	*
	* These devices may alternatively/additionally be configured using AT
	* commands on any of the serial interfaces driven by the option driver
	*
	* This driver binds only to the data ("slave") interface to enable
	* the cdc-wdm driver to bind to the control interface. It still
	* parses the CDC functional descriptors on the control interface to
	* a) verify that this is indeed a handled interface (CDC Union
	* header lists it as slave)
	* b) get MAC address and other ethernet config from the CDC Ethernet
	* header
	* c) enable user bind requests against the control interface, which
	* is the common way to bind to CDC Ethernet Control Model type
	* interfaces
	* d) provide a hint to the user about which interface is the
	* corresponding management interface
	*/

	static int qmi_wwan_bind(struct usbnet dev, struct usb_interface intf)
	{
	int status = -1;
	struct usb_interface *control = NULL;
	u8 *buf = intf->cur_altsetting->extra;
	int len = intf->cur_altsetting->extralen;
	struct usb_interface_descriptor *desc = &intf->cur_altsetting->desc;
	struct usb_cdc_union_desc *cdc_union = NULL;
	struct usb_cdc_ether_desc *cdc_ether = NULL;
	u32 required = 1 << USB_CDC_HEADER_TYPE \| 1 << USB_CDC_UNION_TYPE;
	u32 found = 0;
	atomic_t pmcount = (void )&dev->data[1];

	atomic_set(pmcount, 0);

	/*
	* assume a data interface has no additional descriptors and
	* that the control and data interface are numbered
	* consecutively - this holds for the Huawei device at least
	*/
	if (len == 0 && desc->bInterfaceNumber > 0) {
	control = usb_ifnum_to_if(dev->udev, desc->bInterfaceNumber - 1);
	if (!control)
	goto err;

	buf = control->cur_altsetting->extra;
	len = control->cur_altsetting->extralen;
	dev_dbg(&intf->dev, "guessing \"control\" => %s, \"data\" => this\n",
	dev_name(&control->dev));
	}

	while (len > 3) {
	struct usb_descriptor_header h = (void )buf;

	/* ignore any misplaced descriptors */
	if (h->bDescriptorType != USB_DT_CS_INTERFACE)
	goto next_desc;

	/* buf[2] is CDC descriptor subtype */
	switch (buf[2]) {
	case USB_CDC_HEADER_TYPE:
	if (found & 1 << USB_CDC_HEADER_TYPE) {
	dev_dbg(&intf->dev, "extra CDC header\n");
	goto err;
	}
	if (h->bLength != sizeof(struct usb_cdc_header_desc)) {
	dev_dbg(&intf->dev, "CDC header len %u\n", h->bLength);
	goto err;
	}
	break;
	case USB_CDC_UNION_TYPE:
	if (found & 1 << USB_CDC_UNION_TYPE) {
	dev_dbg(&intf->dev, "extra CDC union\n");
	goto err;
	}
	if (h->bLength != sizeof(struct usb_cdc_union_desc)) {
	dev_dbg(&intf->dev, "CDC union len %u\n", h->bLength);
	goto err;
	}
	cdc_union = (struct usb_cdc_union_desc *)buf;
	break;
	case USB_CDC_ETHERNET_TYPE:
	if (found & 1 << USB_CDC_ETHERNET_TYPE) {
	dev_dbg(&intf->dev, "extra CDC ether\n");
	goto err;
	}
	if (h->bLength != sizeof(struct usb_cdc_ether_desc)) {
	dev_dbg(&intf->dev, "CDC ether len %u\n", h->bLength);
	goto err;
	}
	cdc_ether = (struct usb_cdc_ether_desc *)buf;
	break;
	}

	/*
	* Remember which CDC functional descriptors we've seen. Works
	* for all types we care about, of which USB_CDC_ETHERNET_TYPE
	* (0x0f) is the highest numbered
	*/
	if (buf[2] < 32)
	found \|= 1 << buf[2];

	next_desc:
	len -= h->bLength;
	buf += h->bLength;
	}

	/* did we find all the required ones? */
	if ((found & required) != required) {
	dev_err(&intf->dev, "CDC functional descriptors missing\n");
	goto err;
	}

	/* give the user a helpful hint if trying to bind to the wrong interface */
	if (cdc_union && desc->bInterfaceNumber == cdc_union->bMasterInterface0) {
	dev_err(&intf->dev, "leaving \"control\" interface for " DM_DRIVER " - try binding to %s instead!\n",
	dev_name(&usb_ifnum_to_if(dev->udev, cdc_union->bSlaveInterface0)->dev));
	goto err;
	}

	/* errors aren't fatal - we can live with the dynamic address */
	if (cdc_ether) {
	dev->hard_mtu = le16_to_cpu(cdc_ether->wMaxSegmentSize);
	usbnet_get_ethernet_addr(dev, cdc_ether->iMACAddress);
	}

	/* success! point the user to the management interface */
	if (control)
	dev_info(&intf->dev, "Use \"" DM_DRIVER "\" for QMI interface %s\n",
	dev_name(&control->dev));

	/* XXX: add a sysfs symlink somewhere to help management applications find it? */

	/* collect bulk endpoints now that we know intf == "data" interface */
	status = usbnet_get_endpoints(dev, intf);

	err:
	return status;
	}

	/* using a counter to merge subdriver requests with our own into a combined state */
	static int qmi_wwan_manage_power(struct usbnet *dev, int on)
	{
	atomic_t pmcount = (void )&dev->data[1];
	int rv = 0;

	dev_dbg(&dev->intf->dev, "%s() pmcount=%d, on=%d\n", __func__, atomic_read(pmcount), on);

	if ((on && atomic_add_return(1, pmcount) == 1) \|\| (!on && atomic_dec_and_test(pmcount))) {
	/* need autopm_get/put here to ensure the usbcore sees the new value */
	rv = usb_autopm_get_interface(dev->intf);
	if (rv < 0)
	goto err;
	dev->intf->needs_remote_wakeup = on;
	usb_autopm_put_interface(dev->intf);
	}
	err:
	return rv;
	}

	static int qmi_wwan_cdc_wdm_manage_power(struct usb_interface *intf, int on)
	{
	struct usbnet *dev = usb_get_intfdata(intf);
	return qmi_wwan_manage_power(dev, on);
	}

	/* Some devices combine the "control" and "data" functions into a
	* single interface with all three endpoints: interrupt + bulk in and
	* out
	*
	* Setting up cdc-wdm as a subdriver owning the interrupt endpoint
	* will let it provide userspace access to the encapsulated QMI
	* protocol without interfering with the usbnet operations.
	*/
	static int qmi_wwan_bind_shared(struct usbnet dev, struct usb_interface intf)
	{
	int rv;
	struct usb_driver *subdriver = NULL;
	atomic_t pmcount = (void )&dev->data[1];

	/* ZTE makes devices where the interface descriptors and endpoint
	* configurations of two or more interfaces are identical, even
	* though the functions are completely different. If set, then
	* driver_info->data is a bitmap of acceptable interface numbers
	* allowing us to bind to one such interface without binding to
	* all of them
	*/
	if (dev->driver_info->data &&
	!test_bit(intf->cur_altsetting->desc.bInterfaceNumber, &dev->driver_info->data)) {
	dev_info(&intf->dev, "not on our whitelist - ignored");
	rv = -ENODEV;
	goto err;
	}

	atomic_set(pmcount, 0);

	/* collect all three endpoints */
	rv = usbnet_get_endpoints(dev, intf);
	if (rv < 0)
	goto err;

	/* require interrupt endpoint for subdriver */
	if (!dev->status) {
	rv = -EINVAL;
	goto err;
	}

	subdriver = usb_cdc_wdm_register(intf, &dev->status->desc, 512, &qmi_wwan_cdc_wdm_manage_power);
	if (IS_ERR(subdriver)) {
	rv = PTR_ERR(subdriver);
	goto err;
	}

	/* can't let usbnet use the interrupt endpoint */
	dev->status = NULL;

	/* save subdriver struct for suspend/resume wrappers */
	dev->data[0] = (unsigned long)subdriver;

	err:
	return rv;
	}

	/* Gobi devices uses identical class/protocol codes for all interfaces regardless
	* of function. Some of these are CDC ACM like and have the exact same endpoints
	* we are looking for. This leaves two possible strategies for identifying the
	* correct interface:
	* a) hardcoding interface number, or
	* b) use the fact that the wwan interface is the only one lacking additional
	* (CDC functional) descriptors
	*
	* Let's see if we can get away with the generic b) solution.
	*/
	static int qmi_wwan_bind_gobi(struct usbnet dev, struct usb_interface intf)
	{
	int rv = -EINVAL;

	/* ignore any interface with additional descriptors */
	if (intf->cur_altsetting->extralen)
	goto err;

	rv = qmi_wwan_bind_shared(dev, intf);
	err:
	return rv;
	}

	static void qmi_wwan_unbind_shared(struct usbnet dev, struct usb_interface intf)
	{
	struct usb_driver subdriver = (void )dev->data[0];

	if (subdriver && subdriver->disconnect)
	subdriver->disconnect(intf);

	dev->data[0] = (unsigned long)NULL;
	}

	/* suspend/resume wrappers calling both usbnet and the cdc-wdm
	* subdriver if present.
	*
	* NOTE: cdc-wdm also supports pre/post_reset, but we cannot provide
	* wrappers for those without adding usbnet reset support first.
	*/
	static int qmi_wwan_suspend(struct usb_interface *intf, pm_message_t message)
	{
	struct usbnet *dev = usb_get_intfdata(intf);
	struct usb_driver subdriver = (void )dev->data[0];
	int ret;

	ret = usbnet_suspend(intf, message);
	if (ret < 0)
	goto err;

	if (subdriver && subdriver->suspend)
	ret = subdriver->suspend(intf, message);
	if (ret < 0)
	usbnet_resume(intf);
	err:
	return ret;
	}

	static int qmi_wwan_resume(struct usb_interface *intf)
	{
	struct usbnet *dev = usb_get_intfdata(intf);
	struct usb_driver subdriver = (void )dev->data[0];
	int ret = 0;

	if (subdriver && subdriver->resume)
	ret = subdriver->resume(intf);
	if (ret < 0)
	goto err;
	ret = usbnet_resume(intf);
	if (ret < 0 && subdriver && subdriver->resume && subdriver->suspend)
	subdriver->suspend(intf, PMSG_SUSPEND);
	err:
	return ret;
	}


	static const struct driver_info qmi_wwan_info = {
	.description = "QMI speaking wwan device",
	.flags = FLAG_WWAN,
	.bind = qmi_wwan_bind,
	.manage_power = qmi_wwan_manage_power,
	};

	static const struct driver_info qmi_wwan_shared = {
	.description = "QMI speaking wwan device with combined interface",
	.flags = FLAG_WWAN,
	.bind = qmi_wwan_bind_shared,
	.unbind = qmi_wwan_unbind_shared,
	.manage_power = qmi_wwan_manage_power,
	};

	static const struct driver_info qmi_wwan_gobi = {
	.description = "Qualcomm Gobi wwan/QMI device",
	.flags = FLAG_WWAN,
	.bind = qmi_wwan_bind_gobi,
	.unbind = qmi_wwan_unbind_shared,
	.manage_power = qmi_wwan_manage_power,
	};

	/* ZTE suck at making USB descriptors */
	static const struct driver_info qmi_wwan_force_int4 = {
	.description = "Qualcomm Gobi wwan/QMI device",
	.flags = FLAG_WWAN,
	.bind = qmi_wwan_bind_gobi,
	.unbind = qmi_wwan_unbind_shared,
	.manage_power = qmi_wwan_manage_power,
	.data = BIT(4), /* interface whitelist bitmap */
	};


	#define HUAWEI_VENDOR_ID 0x12D1
	#define QMI_GOBI_DEVICE(vend, prod) \
	USB_DEVICE(vend, prod), \
	.driver_info = (unsigned long)&qmi_wwan_gobi

	static const struct usb_device_id products[] = {
	{ /* Huawei E392, E398 and possibly others sharing both device id and more... */
	.match_flags = USB_DEVICE_ID_MATCH_VENDOR \| USB_DEVICE_ID_MATCH_INT_INFO,
	.idVendor = HUAWEI_VENDOR_ID,
	.bInterfaceClass = USB_CLASS_VENDOR_SPEC,
	.bInterfaceSubClass = 1,
	.bInterfaceProtocol = 8, /* NOTE: This is the slave interface of the CDC Union! */
	.driver_info = (unsigned long)&qmi_wwan_info,
	},
	{ /* Huawei E392, E398 and possibly others in "Windows mode"
	* using a combined control and data interface without any CDC
	* functional descriptors
	*/
	.match_flags = USB_DEVICE_ID_MATCH_VENDOR \| USB_DEVICE_ID_MATCH_INT_INFO,
	.idVendor = HUAWEI_VENDOR_ID,
	.bInterfaceClass = USB_CLASS_VENDOR_SPEC,
	.bInterfaceSubClass = 1,
	.bInterfaceProtocol = 17,
	.driver_info = (unsigned long)&qmi_wwan_shared,
	},
	{ /* Pantech UML290 */
	.match_flags = USB_DEVICE_ID_MATCH_DEVICE \| USB_DEVICE_ID_MATCH_INT_INFO,
	.idVendor = 0x106c,
	.idProduct = 0x3718,
	.bInterfaceClass = 0xff,
	.bInterfaceSubClass = 0xf0,
	.bInterfaceProtocol = 0xff,
	.driver_info = (unsigned long)&qmi_wwan_shared,
	},
	{ /* ZTE MF820D */
	.match_flags = USB_DEVICE_ID_MATCH_DEVICE \| USB_DEVICE_ID_MATCH_INT_INFO,
	.idVendor = 0x19d2,
	.idProduct = 0x0167,
	.bInterfaceClass = 0xff,
	.bInterfaceSubClass = 0xff,
	.bInterfaceProtocol = 0xff,
	.driver_info = (unsigned long)&qmi_wwan_force_int4,
	},
	{ /* ZTE (Vodafone) K3565-Z */
	.match_flags = USB_DEVICE_ID_MATCH_DEVICE \| USB_DEVICE_ID_MATCH_INT_INFO,
	.idVendor = 0x19d2,
	.idProduct = 0x0063,
	.bInterfaceClass = 0xff,
	.bInterfaceSubClass = 0xff,
	.bInterfaceProtocol = 0xff,
	.driver_info = (unsigned long)&qmi_wwan_force_int4,
	},
	{ /* ZTE (Vodafone) K3570-Z */
	.match_flags = USB_DEVICE_ID_MATCH_DEVICE \| USB_DEVICE_ID_MATCH_INT_INFO,
	.idVendor = 0x19d2,
	.idProduct = 0x1008,
	.bInterfaceClass = 0xff,
	.bInterfaceSubClass = 0xff,
	.bInterfaceProtocol = 0xff,
	.driver_info = (unsigned long)&qmi_wwan_force_int4,
	},
	{ /* ZTE (Vodafone) K3571-Z */
	.match_flags = USB_DEVICE_ID_MATCH_DEVICE \| USB_DEVICE_ID_MATCH_INT_INFO,
	.idVendor = 0x19d2,
	.idProduct = 0x1010,
	.bInterfaceClass = 0xff,
	.bInterfaceSubClass = 0xff,
	.bInterfaceProtocol = 0xff,
	.driver_info = (unsigned long)&qmi_wwan_force_int4,
	},
	{ /* ZTE (Vodafone) K4505-Z */
	.match_flags = USB_DEVICE_ID_MATCH_DEVICE \| USB_DEVICE_ID_MATCH_INT_INFO,
	.idVendor = 0x19d2,
	.idProduct = 0x0104,
	.bInterfaceClass = 0xff,
	.bInterfaceSubClass = 0xff,
	.bInterfaceProtocol = 0xff,
	.driver_info = (unsigned long)&qmi_wwan_force_int4,
	},
	{QMI_GOBI_DEVICE(0x05c6, 0x9212)}, /* Acer Gobi Modem Device */
	{QMI_GOBI_DEVICE(0x03f0, 0x1f1d)}, /* HP un2400 Gobi Modem Device */
	{QMI_GOBI_DEVICE(0x03f0, 0x371d)}, /* HP un2430 Mobile Broadband Module */
	{QMI_GOBI_DEVICE(0x04da, 0x250d)}, /* Panasonic Gobi Modem device */
	{QMI_GOBI_DEVICE(0x413c, 0x8172)}, /* Dell Gobi Modem device */
	{QMI_GOBI_DEVICE(0x1410, 0xa001)}, /* Novatel Gobi Modem device */
	{QMI_GOBI_DEVICE(0x0b05, 0x1776)}, /* Asus Gobi Modem device */
	{QMI_GOBI_DEVICE(0x19d2, 0xfff3)}, /* ONDA Gobi Modem device */
	{QMI_GOBI_DEVICE(0x05c6, 0x9001)}, /* Generic Gobi Modem device */
	{QMI_GOBI_DEVICE(0x05c6, 0x9002)}, /* Generic Gobi Modem device */
	{QMI_GOBI_DEVICE(0x05c6, 0x9202)}, /* Generic Gobi Modem device */
	{QMI_GOBI_DEVICE(0x05c6, 0x9203)}, /* Generic Gobi Modem device */
	{QMI_GOBI_DEVICE(0x05c6, 0x9222)}, /* Generic Gobi Modem device */
	{QMI_GOBI_DEVICE(0x05c6, 0x9009)}, /* Generic Gobi Modem device */
	{QMI_GOBI_DEVICE(0x413c, 0x8186)}, /* Dell Gobi 2000 Modem device (N0218, VU936) */
	{QMI_GOBI_DEVICE(0x05c6, 0x920b)}, /* Generic Gobi 2000 Modem device */
	{QMI_GOBI_DEVICE(0x05c6, 0x9225)}, /* Sony Gobi 2000 Modem device (N0279, VU730) */
	{QMI_GOBI_DEVICE(0x05c6, 0x9245)}, /* Samsung Gobi 2000 Modem device (VL176) */
	{QMI_GOBI_DEVICE(0x03f0, 0x251d)}, /* HP Gobi 2000 Modem device (VP412) */
	{QMI_GOBI_DEVICE(0x05c6, 0x9215)}, /* Acer Gobi 2000 Modem device (VP413) */
	{QMI_GOBI_DEVICE(0x05c6, 0x9265)}, /* Asus Gobi 2000 Modem device (VR305) */
	{QMI_GOBI_DEVICE(0x05c6, 0x9235)}, /* Top Global Gobi 2000 Modem device (VR306) */
	{QMI_GOBI_DEVICE(0x05c6, 0x9275)}, /* iRex Technologies Gobi 2000 Modem device (VR307) */
	{QMI_GOBI_DEVICE(0x1199, 0x9001)}, /* Sierra Wireless Gobi 2000 Modem device (VT773) */
	{QMI_GOBI_DEVICE(0x1199, 0x9002)}, /* Sierra Wireless Gobi 2000 Modem device (VT773) */
	{QMI_GOBI_DEVICE(0x1199, 0x9003)}, /* Sierra Wireless Gobi 2000 Modem device (VT773) */
	{QMI_GOBI_DEVICE(0x1199, 0x9004)}, /* Sierra Wireless Gobi 2000 Modem device (VT773) */
	{QMI_GOBI_DEVICE(0x1199, 0x9005)}, /* Sierra Wireless Gobi 2000 Modem device (VT773) */
	{QMI_GOBI_DEVICE(0x1199, 0x9006)}, /* Sierra Wireless Gobi 2000 Modem device (VT773) */
	{QMI_GOBI_DEVICE(0x1199, 0x9007)}, /* Sierra Wireless Gobi 2000 Modem device (VT773) */
	{QMI_GOBI_DEVICE(0x1199, 0x9008)}, /* Sierra Wireless Gobi 2000 Modem device (VT773) */
	{QMI_GOBI_DEVICE(0x1199, 0x9009)}, /* Sierra Wireless Gobi 2000 Modem device (VT773) */
	{QMI_GOBI_DEVICE(0x1199, 0x900a)}, /* Sierra Wireless Gobi 2000 Modem device (VT773) */
	{QMI_GOBI_DEVICE(0x1199, 0x9011)}, /* Sierra Wireless Gobi 2000 Modem device (MC8305) */
	{QMI_GOBI_DEVICE(0x16d8, 0x8002)}, /* CMDTech Gobi 2000 Modem device (VU922) */
	{QMI_GOBI_DEVICE(0x05c6, 0x9205)}, /* Gobi 2000 Modem device */
	{QMI_GOBI_DEVICE(0x1199, 0x9013)}, /* Sierra Wireless Gobi 3000 Modem device (MC8355) */
	{ } /* END */
	};
	MODULE_DEVICE_TABLE(usb, products);

	static struct usb_driver qmi_wwan_driver = {
	.name = "qmi_wwan",
	.id_table = products,
	.probe = usbnet_probe,
	.disconnect = usbnet_disconnect,
	.suspend = qmi_wwan_suspend,
	.resume = qmi_wwan_resume,
	.reset_resume = qmi_wwan_resume,
	.supports_autosuspend = 1,
	};

	static int __init qmi_wwan_init(void)
	{
	return usb_register(&qmi_wwan_driver);
	}
	module_init(qmi_wwan_init);

	static void __exit qmi_wwan_exit(void)
	{
	usb_deregister(&qmi_wwan_driver);
	}
	module_exit(qmi_wwan_exit);

	MODULE_AUTHOR("Bjørn Mork <bjorn@mork.no>");
	MODULE_DESCRIPTION("Qualcomm MSM Interface (QMI) WWAN driver");
	MODULE_LICENSE("GPL");