drivers/net/usb/cx82310_eth.c

   1 /*
   2  * Driver for USB ethernet port of Conexant CX82310-based ADSL routers
   3  * Copyright (C) 2010 by Ondrej Zary
   4  * some parts inspired by the cxacru driver
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20
  21 #include <linux/module.h>
  22 #include <linux/init.h>
  23 #include <linux/netdevice.h>
  24 #include <linux/etherdevice.h>
  25 #include <linux/ethtool.h>
  26 #include <linux/workqueue.h>
  27 #include <linux/mii.h>
  28 #include <linux/usb.h>
  29 #include <linux/usb/usbnet.h>
  30
  31 enum cx82310_cmd {
  32         CMD_START               = 0x84, /* no effect? */
  33         CMD_STOP                = 0x85, /* no effect? */
  34         CMD_GET_STATUS          = 0x90, /* returns nothing? */
  35         CMD_GET_MAC_ADDR        = 0x91, /* read MAC address */
  36         CMD_GET_LINK_STATUS     = 0x92, /* not useful, link is always up */
  37         CMD_ETHERNET_MODE       = 0x99, /* unknown, needed during init */
  38 };
  39
  40 enum cx82310_status {
  41         STATUS_UNDEFINED,
  42         STATUS_SUCCESS,
  43         STATUS_ERROR,
  44         STATUS_UNSUPPORTED,
  45         STATUS_UNIMPLEMENTED,
  46         STATUS_PARAMETER_ERROR,
  47         STATUS_DBG_LOOPBACK,
  48 };
  49
  50 #define CMD_PACKET_SIZE 64
  51 /* first command after power on can take around 8 seconds */
  52 #define CMD_TIMEOUT     15000
  53 #define CMD_REPLY_RETRY 5
  54
  55 #define CX82310_MTU     1514
  56 #define CMD_EP          0x01
  57
  58 /*
  59  * execute control command
  60  *  - optionally send some data (command parameters)
  61  *  - optionally wait for the reply
  62  *  - optionally read some data from the reply
  63  */
  64 static int cx82310_cmd(struct usbnet *dev, enum cx82310_cmd cmd, bool reply,
  65                        u8 *wdata, int wlen, u8 *rdata, int rlen)
  66 {
  67         int actual_len, retries, ret;
  68         struct usb_device *udev = dev->udev;
  69         u8 *buf = kzalloc(CMD_PACKET_SIZE, GFP_KERNEL);
  70
  71         if (!buf)
  72                 return -ENOMEM;
  73
  74         /* create command packet */
  75         buf[0] = cmd;
  76         if (wdata)
  77                 memcpy(buf + 4, wdata, min_t(int, wlen, CMD_PACKET_SIZE - 4));
  78
  79         /* send command packet */
  80         ret = usb_bulk_msg(udev, usb_sndbulkpipe(udev, CMD_EP), buf,
  81                            CMD_PACKET_SIZE, &actual_len, CMD_TIMEOUT);
  82         if (ret < 0) {
  83                 dev_err(&dev->udev->dev, "send command %#x: error %d\n",
  84                         cmd, ret);
  85                 goto end;
  86         }
  87
  88         if (reply) {
  89                 /* wait for reply, retry if it's empty */
  90                 for (retries = 0; retries < CMD_REPLY_RETRY; retries++) {
  91                         ret = usb_bulk_msg(udev, usb_rcvbulkpipe(udev, CMD_EP),
  92                                            buf, CMD_PACKET_SIZE, &actual_len,
  93                                            CMD_TIMEOUT);
  94                         if (ret < 0) {
  95                                 dev_err(&dev->udev->dev,
  96                                         "reply receive error %d\n", ret);
  97                                 goto end;
  98                         }
  99                         if (actual_len > 0)
 100                                 break;
 101                 }
 102                 if (actual_len == 0) {
 103                         dev_err(&dev->udev->dev, "no reply to command %#x\n",
 104                                 cmd);
 105                         ret = -EIO;
 106                         goto end;
 107                 }
 108                 if (buf[0] != cmd) {
 109                         dev_err(&dev->udev->dev,
 110                                 "got reply to command %#x, expected: %#x\n",
 111                                 buf[0], cmd);
 112                         ret = -EIO;
 113                         goto end;
 114                 }
 115                 if (buf[1] != STATUS_SUCCESS) {
 116                         dev_err(&dev->udev->dev, "command %#x failed: %#x\n",
 117                                 cmd, buf[1]);
 118                         ret = -EIO;
 119                         goto end;
 120                 }
 121                 if (rdata)
 122                         memcpy(rdata, buf + 4,
 123                                min_t(int, rlen, CMD_PACKET_SIZE - 4));
 124         }
 125 end:
 126         kfree(buf);
 127         return ret;
 128 }
 129
 130 #define partial_len     data[0]         /* length of partial packet data */
 131 #define partial_rem     data[1]         /* remaining (missing) data length */
 132 #define partial_data    data[2]         /* partial packet data */
 133
 134 static int cx82310_bind(struct usbnet *dev, struct usb_interface *intf)
 135 {
 136         int ret;
 137         char buf[15];
 138         struct usb_device *udev = dev->udev;
 139
 140         /* avoid ADSL modems - continue only if iProduct is "USB NET CARD" */
 141         if (usb_string(udev, udev->descriptor.iProduct, buf, sizeof(buf)) > 0
 142             && strcmp(buf, "USB NET CARD")) {
 143                 dev_info(&udev->dev, "ignoring: probably an ADSL modem\n");
 144                 return -ENODEV;
 145         }
 146
 147         ret = usbnet_get_endpoints(dev, intf);
 148         if (ret)
 149                 return ret;
 150
 151         /*
 152          * this must not include ethernet header as the device can send partial
 153          * packets with no header (and sometimes even empty URBs)
 154          */
 155         dev->net->hard_header_len = 0;
 156         /* we can send at most 1514 bytes of data (+ 2-byte header) per URB */
 157         dev->hard_mtu = CX82310_MTU + 2;
 158         /* we can receive URBs up to 4KB from the device */
 159         dev->rx_urb_size = 4096;
 160
 161         dev->partial_data = (unsigned long) kmalloc(dev->hard_mtu, GFP_KERNEL);
 162         if (!dev->partial_data)
 163                 return -ENOMEM;
 164
 165         /* enable ethernet mode (?) */
 166         ret = cx82310_cmd(dev, CMD_ETHERNET_MODE, true, "\x01", 1, NULL, 0);
 167         if (ret) {
 168                 dev_err(&udev->dev, "unable to enable ethernet mode: %d\n",
 169                         ret);
 170                 goto err;
 171         }
 172
 173         /* get the MAC address */
 174         ret = cx82310_cmd(dev, CMD_GET_MAC_ADDR, true, NULL, 0,
 175                           dev->net->dev_addr, ETH_ALEN);
 176         if (ret) {
 177                 dev_err(&udev->dev, "unable to read MAC address: %d\n", ret);
 178                 goto err;
 179         }
 180
 181         /* start (does not seem to have any effect?) */
 182         ret = cx82310_cmd(dev, CMD_START, false, NULL, 0, NULL, 0);
 183         if (ret)
 184                 goto err;
 185
 186         return 0;
 187 err:
 188         kfree((void *)dev->partial_data);
 189         return ret;
 190 }
 191
 192 static void cx82310_unbind(struct usbnet *dev, struct usb_interface *intf)
 193 {
 194         kfree((void *)dev->partial_data);
 195 }
 196
 197 /*
 198  * RX is NOT easy - we can receive multiple packets per skb, each having 2-byte
 199  * packet length at the beginning.
 200  * The last packet might be incomplete (when it crosses the 4KB URB size),
 201  * continuing in the next skb (without any headers).
 202  * If a packet has odd length, there is one extra byte at the end (before next
 203  * packet or at the end of the URB).
 204  */
 205 static int cx82310_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
 206 {
 207         int len;
 208         struct sk_buff *skb2;
 209
 210         /*
 211          * If the last skb ended with an incomplete packet, this skb contains
 212          * end of that packet at the beginning.
 213          */
 214         if (dev->partial_rem) {
 215                 len = dev->partial_len + dev->partial_rem;
 216                 skb2 = alloc_skb(len, GFP_ATOMIC);
 217                 if (!skb2)
 218                         return 0;
 219                 skb_put(skb2, len);
 220                 memcpy(skb2->data, (void *)dev->partial_data,
 221                        dev->partial_len);
 222                 memcpy(skb2->data + dev->partial_len, skb->data,
 223                        dev->partial_rem);
 224                 usbnet_skb_return(dev, skb2);
 225                 skb_pull(skb, (dev->partial_rem + 1) & ~1);
 226                 dev->partial_rem = 0;
 227                 if (skb->len < 2)
 228                         return 1;
 229         }
 230
 231         /* a skb can contain multiple packets */
 232         while (skb->len > 1) {
 233                 /* first two bytes are packet length */
 234                 len = skb->data[0] | (skb->data[1] << 8);
 235                 skb_pull(skb, 2);
 236
 237                 /* if last packet in the skb, let usbnet to process it */
 238                 if (len == skb->len || len + 1 == skb->len) {
 239                         skb_trim(skb, len);
 240                         break;
 241                 }
 242
 243                 if (len > CX82310_MTU) {
 244                         dev_err(&dev->udev->dev, "RX packet too long: %d B\n",
 245                                 len);
 246                         return 0;
 247                 }
 248
 249                 /* incomplete packet, save it for the next skb */
 250                 if (len > skb->len) {
 251                         dev->partial_len = skb->len;
 252                         dev->partial_rem = len - skb->len;
 253                         memcpy((void *)dev->partial_data, skb->data,
 254                                dev->partial_len);
 255                         skb_pull(skb, skb->len);
 256                         break;
 257                 }
 258
 259                 skb2 = alloc_skb(len, GFP_ATOMIC);
 260                 if (!skb2)
 261                         return 0;
 262                 skb_put(skb2, len);
 263                 memcpy(skb2->data, skb->data, len);
 264                 /* process the packet */
 265                 usbnet_skb_return(dev, skb2);
 266
 267                 skb_pull(skb, (len + 1) & ~1);
 268         }
 269
 270         /* let usbnet process the last packet */
 271         return 1;
 272 }
 273
 274 /* TX is easy, just add 2 bytes of length at the beginning */
 275 static struct sk_buff *cx82310_tx_fixup(struct usbnet *dev, struct sk_buff *skb,
 276                                        gfp_t flags)
 277 {
 278         int len = skb->len;
 279
 280         if (skb_headroom(skb) < 2) {
 281                 struct sk_buff *skb2 = skb_copy_expand(skb, 2, 0, flags);
 282                 dev_kfree_skb_any(skb);
 283                 skb = skb2;
 284                 if (!skb)
 285                         return NULL;
 286         }
 287         skb_push(skb, 2);
 288
 289         skb->data[0] = len;
 290         skb->data[1] = len >> 8;
 291
 292         return skb;
 293 }
 294
 295
 296 static const struct driver_info cx82310_info = {
 297         .description    = "Conexant CX82310 USB ethernet",
 298         .flags          = FLAG_ETHER,
 299         .bind           = cx82310_bind,
 300         .unbind         = cx82310_unbind,
 301         .rx_fixup       = cx82310_rx_fixup,
 302         .tx_fixup       = cx82310_tx_fixup,
 303 };
 304
 305 static const struct usb_device_id products[] = {
 306         {
 307                 USB_DEVICE_AND_INTERFACE_INFO(0x0572, 0xcb01, 0xff, 0, 0),
 308                 .driver_info = (unsigned long) &cx82310_info
 309         },
 310         { },
 311 };
 312 MODULE_DEVICE_TABLE(usb, products);
 313
 314 static struct usb_driver cx82310_driver = {
 315         .name           = "cx82310_eth",
 316         .id_table       = products,
 317         .probe          = usbnet_probe,
 318         .disconnect     = usbnet_disconnect,
 319         .suspend        = usbnet_suspend,
 320         .resume         = usbnet_resume,
 321         .disable_hub_initiated_lpm = 1,
 322 };
 323
 324 module_usb_driver(cx82310_driver);
 325
 326 MODULE_AUTHOR("Ondrej Zary");
 327 MODULE_DESCRIPTION("Conexant CX82310-based ADSL router USB ethernet driver");
 328 MODULE_LICENSE("GPL");