/* * Copyright (c) 2012 Bjørn Mork * * 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 #include #include #include #include #include #include /* 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 "); MODULE_DESCRIPTION("Qualcomm MSM Interface (QMI) WWAN driver"); MODULE_LICENSE("GPL");