--- /dev/null
+/*
+ * 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");
projects / cascardo / linux.git / commitdiff