/*
* 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>
/* 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;
/*
* 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;
}
/* stolen from cdc_ether.c */
static int qmi_wwan_manage_power(struct usbnet *dev, int on)
{
dev->intf->needs_remote_wakeup = on;
return 0;
}
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,
};
#define HUAWEI_VENDOR_ID 0x12D1
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,
}, {
}, /* 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 = usbnet_suspend,
.resume = usbnet_resume,
.reset_resume = usbnet_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");
