diff options
Diffstat (limited to 'drivers/net/usb/qmi_wwan.c')
| -rw-r--r-- | drivers/net/usb/qmi_wwan.c | 228 |
1 files changed, 228 insertions, 0 deletions
diff --git a/drivers/net/usb/qmi_wwan.c b/drivers/net/usb/qmi_wwan.c new file mode 100644 index 000000000000..739e6de7abcb --- /dev/null +++ b/drivers/net/usb/qmi_wwan.c @@ -0,0 +1,228 @@ +/* + * 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"); |