drivers/net/usb/huawei_cdc_ncm.c

   1 /* huawei_cdc_ncm.c - handles Huawei devices using the CDC NCM protocol as
   2  * transport layer.
   3  * Copyright (C) 2013    Enrico Mioso <mrkiko.rs@gmail.com>
   4  *
   5  *
   6  * ABSTRACT:
   7  * This driver handles devices resembling the CDC NCM standard, but
   8  * encapsulating another protocol inside it. An example are some Huawei 3G
   9  * devices, exposing an embedded AT channel where you can set up the NCM
  10  * connection.
  11  * This code has been heavily inspired by the cdc_mbim.c driver, which is
  12  * Copyright (c) 2012  Smith Micro Software, Inc.
  13  * Copyright (c) 2012  Bjørn Mork <bjorn@mork.no>
  14  *
  15  * This program is free software; you can redistribute it and/or
  16  * modify it under the terms of the GNU General Public License
  17  * version 2 as published by the Free Software Foundation.
  18  */
  19
  20 #include <linux/module.h>
  21 #include <linux/netdevice.h>
  22 #include <linux/ethtool.h>
  23 #include <linux/if_vlan.h>
  24 #include <linux/ip.h>
  25 #include <linux/mii.h>
  26 #include <linux/usb.h>
  27 #include <linux/usb/cdc.h>
  28 #include <linux/usb/usbnet.h>
  29 #include <linux/usb/cdc-wdm.h>
  30 #include <linux/usb/cdc_ncm.h>
  31
  32 /* Driver data */
  33 struct huawei_cdc_ncm_state {
  34         struct cdc_ncm_ctx *ctx;
  35         atomic_t pmcount;
  36         struct usb_driver *subdriver;
  37         struct usb_interface *control;
  38         struct usb_interface *data;
  39 };
  40
  41 static int huawei_cdc_ncm_manage_power(struct usbnet *usbnet_dev, int on)
  42 {
  43         struct huawei_cdc_ncm_state *drvstate = (void *)&usbnet_dev->data;
  44         int rv;
  45
  46         if ((on && atomic_add_return(1, &drvstate->pmcount) == 1) ||
  47                         (!on && atomic_dec_and_test(&drvstate->pmcount))) {
  48                 rv = usb_autopm_get_interface(usbnet_dev->intf);
  49                 usbnet_dev->intf->needs_remote_wakeup = on;
  50                 if (!rv)
  51                         usb_autopm_put_interface(usbnet_dev->intf);
  52         }
  53         return 0;
  54 }
  55
  56 static int huawei_cdc_ncm_wdm_manage_power(struct usb_interface *intf,
  57                                            int status)
  58 {
  59         struct usbnet *usbnet_dev = usb_get_intfdata(intf);
  60
  61         /* can be called while disconnecting */
  62         if (!usbnet_dev)
  63                 return 0;
  64
  65         return huawei_cdc_ncm_manage_power(usbnet_dev, status);
  66 }
  67
  68
  69 static int huawei_cdc_ncm_bind(struct usbnet *usbnet_dev,
  70                                struct usb_interface *intf)
  71 {
  72         struct cdc_ncm_ctx *ctx;
  73         struct usb_driver *subdriver = ERR_PTR(-ENODEV);
  74         int ret = -ENODEV;
  75         struct huawei_cdc_ncm_state *drvstate = (void *)&usbnet_dev->data;
  76
  77         /* altsetting should always be 1 for NCM devices - so we hard-coded
  78          * it here
  79          */
  80         ret = cdc_ncm_bind_common(usbnet_dev, intf, 1);
  81         if (ret)
  82                 goto err;
  83
  84         ctx = drvstate->ctx;
  85
  86         if (usbnet_dev->status)
  87                 /* CDC-WMC r1.1 requires wMaxCommand to be "at least 256
  88                  * decimal (0x100)"
  89                  */
  90                 subdriver = usb_cdc_wdm_register(ctx->control,
  91                                                  &usbnet_dev->status->desc,
  92                                                  256, /* wMaxCommand */
  93                                                  huawei_cdc_ncm_wdm_manage_power);
  94         if (IS_ERR(subdriver)) {
  95                 ret = PTR_ERR(subdriver);
  96                 cdc_ncm_unbind(usbnet_dev, intf);
  97                 goto err;
  98         }
  99
 100         /* Prevent usbnet from using the status descriptor */
 101         usbnet_dev->status = NULL;
 102
 103         drvstate->subdriver = subdriver;
 104
 105 err:
 106         return ret;
 107 }
 108
 109 static void huawei_cdc_ncm_unbind(struct usbnet *usbnet_dev,
 110                                   struct usb_interface *intf)
 111 {
 112         struct huawei_cdc_ncm_state *drvstate = (void *)&usbnet_dev->data;
 113         struct cdc_ncm_ctx *ctx = drvstate->ctx;
 114
 115         if (drvstate->subdriver && drvstate->subdriver->disconnect)
 116                 drvstate->subdriver->disconnect(ctx->control);
 117         drvstate->subdriver = NULL;
 118
 119         cdc_ncm_unbind(usbnet_dev, intf);
 120 }
 121
 122 static int huawei_cdc_ncm_suspend(struct usb_interface *intf,
 123                                   pm_message_t message)
 124 {
 125         int ret = 0;
 126         struct usbnet *usbnet_dev = usb_get_intfdata(intf);
 127         struct huawei_cdc_ncm_state *drvstate = (void *)&usbnet_dev->data;
 128         struct cdc_ncm_ctx *ctx = drvstate->ctx;
 129
 130         if (ctx == NULL) {
 131                 ret = -ENODEV;
 132                 goto error;
 133         }
 134
 135         ret = usbnet_suspend(intf, message);
 136         if (ret < 0)
 137                 goto error;
 138
 139         if (intf == ctx->control &&
 140                 drvstate->subdriver &&
 141                 drvstate->subdriver->suspend)
 142                 ret = drvstate->subdriver->suspend(intf, message);
 143         if (ret < 0)
 144                 usbnet_resume(intf);
 145
 146 error:
 147         return ret;
 148 }
 149
 150 static int huawei_cdc_ncm_resume(struct usb_interface *intf)
 151 {
 152         int ret = 0;
 153         struct usbnet *usbnet_dev = usb_get_intfdata(intf);
 154         struct huawei_cdc_ncm_state *drvstate = (void *)&usbnet_dev->data;
 155         bool callsub;
 156         struct cdc_ncm_ctx *ctx = drvstate->ctx;
 157
 158         /* should we call subdriver's resume function? */
 159         callsub =
 160                 (intf == ctx->control &&
 161                 drvstate->subdriver &&
 162                 drvstate->subdriver->resume);
 163
 164         if (callsub)
 165                 ret = drvstate->subdriver->resume(intf);
 166         if (ret < 0)
 167                 goto err;
 168         ret = usbnet_resume(intf);
 169         if (ret < 0 && callsub)
 170                 drvstate->subdriver->suspend(intf, PMSG_SUSPEND);
 171 err:
 172         return ret;
 173 }
 174
 175 static int huawei_cdc_ncm_check_connect(struct usbnet *usbnet_dev)
 176 {
 177         struct cdc_ncm_ctx *ctx;
 178
 179         ctx = (struct cdc_ncm_ctx *)usbnet_dev->data[0];
 180
 181         if (ctx == NULL)
 182                 return 1; /* disconnected */
 183
 184         return !ctx->connected;
 185 }
 186
 187 static const struct driver_info huawei_cdc_ncm_info = {
 188         .description = "Huawei CDC NCM device",
 189         .flags = FLAG_NO_SETINT | FLAG_MULTI_PACKET | FLAG_WWAN,
 190         .bind = huawei_cdc_ncm_bind,
 191         .unbind = huawei_cdc_ncm_unbind,
 192         .check_connect = huawei_cdc_ncm_check_connect,
 193         .manage_power = huawei_cdc_ncm_manage_power,
 194         .rx_fixup = cdc_ncm_rx_fixup,
 195         .tx_fixup = cdc_ncm_tx_fixup,
 196 };
 197
 198 static const struct usb_device_id huawei_cdc_ncm_devs[] = {
 199         /* Huawei NCM devices disguised as vendor specific */
 200         { USB_VENDOR_AND_INTERFACE_INFO(0x12d1, 0xff, 0x02, 0x16),
 201           .driver_info = (unsigned long)&huawei_cdc_ncm_info,
 202         },
 203         { USB_VENDOR_AND_INTERFACE_INFO(0x12d1, 0xff, 0x02, 0x46),
 204           .driver_info = (unsigned long)&huawei_cdc_ncm_info,
 205         },
 206         { USB_VENDOR_AND_INTERFACE_INFO(0x12d1, 0xff, 0x02, 0x76),
 207           .driver_info = (unsigned long)&huawei_cdc_ncm_info,
 208         },
 209
 210         /* Terminating entry */
 211         {
 212         },
 213 };
 214 MODULE_DEVICE_TABLE(usb, huawei_cdc_ncm_devs);
 215
 216 static struct usb_driver huawei_cdc_ncm_driver = {
 217         .name = "huawei_cdc_ncm",
 218         .id_table = huawei_cdc_ncm_devs,
 219         .probe = usbnet_probe,
 220         .disconnect = usbnet_disconnect,
 221         .suspend = huawei_cdc_ncm_suspend,
 222         .resume = huawei_cdc_ncm_resume,
 223         .reset_resume = huawei_cdc_ncm_resume,
 224         .supports_autosuspend = 1,
 225         .disable_hub_initiated_lpm = 1,
 226 };
 227 module_usb_driver(huawei_cdc_ncm_driver);
 228 MODULE_AUTHOR("Enrico Mioso <mrkiko.rs@gmail.com>");
 229 MODULE_DESCRIPTION("USB CDC NCM host driver with encapsulated protocol support");
 230 MODULE_LICENSE("GPL");