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, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <linux/module.h>
  21 #include <linux/netdevice.h>
  22 #include <linux/etherdevice.h>
  23 #include <linux/ethtool.h>
  24 #include <linux/workqueue.h>
  25 #include <linux/mii.h>
  26 #include <linux/usb.h>
  27 #include <linux/usb/usbnet.h>
  28
  29 enum cx82310_cmd {
  30         CMD_START               = 0x84, /* no effect? */
  31         CMD_STOP                = 0x85, /* no effect? */
  32         CMD_GET_STATUS          = 0x90, /* returns nothing? */
  33         CMD_GET_MAC_ADDR        = 0x91, /* read MAC address */
  34         CMD_GET_LINK_STATUS     = 0x92, /* not useful, link is always up */
  35         CMD_ETHERNET_MODE       = 0x99, /* unknown, needed during init */
  36 };
  37
  38 enum cx82310_status {
  39         STATUS_UNDEFINED,
  40         STATUS_SUCCESS,
  41         STATUS_ERROR,
  42         STATUS_UNSUPPORTED,
  43         STATUS_UNIMPLEMENTED,
  44         STATUS_PARAMETER_ERROR,
  45         STATUS_DBG_LOOPBACK,
  46 };
  47
  48 #define CMD_PACKET_SIZE 64
  49 #define CMD_TIMEOUT     100
  50 #define CMD_REPLY_RETRY 5
  51
  52 #define CX82310_MTU     1514
  53 #define CMD_EP          0x01
  54
  55 /*
  56  * execute control command
  57  *  - optionally send some data (command parameters)
  58  *  - optionally wait for the reply
  59  *  - optionally read some data from the reply
  60  */
  61 static int cx82310_cmd(struct usbnet *dev, enum cx82310_cmd cmd, bool reply,
  62                        u8 *wdata, int wlen, u8 *rdata, int rlen)
  63 {
  64         int actual_len, retries, ret;
  65         struct usb_device *udev = dev->udev;
  66         u8 *buf = kzalloc(CMD_PACKET_SIZE, GFP_KERNEL);
  67
  68         if (!buf)
  69                 return -ENOMEM;
  70
  71         /* create command packet */
  72         buf[0] = cmd;
  73         if (wdata)
  74                 memcpy(buf + 4, wdata, min_t(int, wlen, CMD_PACKET_SIZE - 4));
  75
  76         /* send command packet */
  77         ret = usb_bulk_msg(udev, usb_sndbulkpipe(udev, CMD_EP), buf,
  78                            CMD_PACKET_SIZE, &actual_len, CMD_TIMEOUT);
  79         if (ret < 0) {
  80                 if (cmd != CMD_GET_LINK_STATUS)
  81                         dev_err(&dev->udev->dev, "send command %#x: error %d\n",
  82                                 cmd, ret);
  83                 goto end;
  84         }
  85
  86         if (reply) {
  87                 /* wait for reply, retry if it's empty */
  88                 for (retries = 0; retries < CMD_REPLY_RETRY; retries++) {
  89                         ret = usb_bulk_msg(udev, usb_rcvbulkpipe(udev, CMD_EP),
  90                                            buf, CMD_PACKET_SIZE, &actual_len,
  91                                            CMD_TIMEOUT);
  92                         if (ret < 0) {
  93                                 if (cmd != CMD_GET_LINK_STATUS)
  94                                         dev_err(&dev->udev->dev,
  95                                                 "reply receive error %d\n",
  96                                                 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         u8 link[3];
 140         int timeout = 50;
 141
 142         /* avoid ADSL modems - continue only if iProduct is "USB NET CARD" */
 143         if (usb_string(udev, udev->descriptor.iProduct, buf, sizeof(buf)) > 0
 144             && strcmp(buf, "USB NET CARD")) {
 145                 dev_info(&udev->dev, "ignoring: probably an ADSL modem\n");
 146                 return -ENODEV;
 147         }
 148
 149         ret = usbnet_get_endpoints(dev, intf);
 150         if (ret)
 151                 return ret;
 152
 153         /*
 154          * this must not include ethernet header as the device can send partial
 155          * packets with no header (and sometimes even empty URBs)
 156          */
 157         dev->net->hard_header_len = 0;
 158         /* we can send at most 1514 bytes of data (+ 2-byte header) per URB */
 159         dev->hard_mtu = CX82310_MTU + 2;
 160         /* we can receive URBs up to 4KB from the device */
 161         dev->rx_urb_size = 4096;
 162
 163         dev->partial_data = (unsigned long) kmalloc(dev->hard_mtu, GFP_KERNEL);
 164         if (!dev->partial_data)
 165                 return -ENOMEM;
 166
 167         /* wait for firmware to become ready (indicated by the link being up) */
 168         while (--timeout) {
 169                 ret = cx82310_cmd(dev, CMD_GET_LINK_STATUS, true, NULL, 0,
 170                                   link, sizeof(link));
 171                 /* the command can time out during boot - it's not an error */
 172                 if (!ret && link[0] == 1 && link[2] == 1)
 173                         break;
 174                 msleep(500);
 175         }
 176         if (!timeout) {
 177                 dev_err(&udev->dev, "firmware not ready in time\n");
 178                 return -ETIMEDOUT;
 179         }
 180
 181         /* enable ethernet mode (?) */
 182         ret = cx82310_cmd(dev, CMD_ETHERNET_MODE, true, "\x01", 1, NULL, 0);
 183         if (ret) {
 184                 dev_err(&udev->dev, "unable to enable ethernet mode: %d\n",
 185                         ret);
 186                 goto err;
 187         }
 188
 189         /* get the MAC address */
 190         ret = cx82310_cmd(dev, CMD_GET_MAC_ADDR, true, NULL, 0,
 191                           dev->net->dev_addr, ETH_ALEN);
 192         if (ret) {
 193                 dev_err(&udev->dev, "unable to read MAC address: %d\n", ret);
 194                 goto err;
 195         }
 196
 197         /* start (does not seem to have any effect?) */
 198         ret = cx82310_cmd(dev, CMD_START, false, NULL, 0, NULL, 0);
 199         if (ret)
 200                 goto err;
 201
 202         return 0;
 203 err:
 204         kfree((void *)dev->partial_data);
 205         return ret;
 206 }
 207
 208 static void cx82310_unbind(struct usbnet *dev, struct usb_interface *intf)
 209 {
 210         kfree((void *)dev->partial_data);
 211 }
 212
 213 /*
 214  * RX is NOT easy - we can receive multiple packets per skb, each having 2-byte
 215  * packet length at the beginning.
 216  * The last packet might be incomplete (when it crosses the 4KB URB size),
 217  * continuing in the next skb (without any headers).
 218  * If a packet has odd length, there is one extra byte at the end (before next
 219  * packet or at the end of the URB).
 220  */
 221 static int cx82310_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
 222 {
 223         int len;
 224         struct sk_buff *skb2;
 225
 226         /*
 227          * If the last skb ended with an incomplete packet, this skb contains
 228          * end of that packet at the beginning.
 229          */
 230         if (dev->partial_rem) {
 231                 len = dev->partial_len + dev->partial_rem;
 232                 skb2 = alloc_skb(len, GFP_ATOMIC);
 233                 if (!skb2)
 234                         return 0;
 235                 skb_put(skb2, len);
 236                 memcpy(skb2->data, (void *)dev->partial_data,
 237                        dev->partial_len);
 238                 memcpy(skb2->data + dev->partial_len, skb->data,
 239                        dev->partial_rem);
 240                 usbnet_skb_return(dev, skb2);
 241                 skb_pull(skb, (dev->partial_rem + 1) & ~1);
 242                 dev->partial_rem = 0;
 243                 if (skb->len < 2)
 244                         return 1;
 245         }
 246
 247         /* a skb can contain multiple packets */
 248         while (skb->len > 1) {
 249                 /* first two bytes are packet length */
 250                 len = skb->data[0] | (skb->data[1] << 8);
 251                 skb_pull(skb, 2);
 252
 253                 /* if last packet in the skb, let usbnet to process it */
 254                 if (len == skb->len || len + 1 == skb->len) {
 255                         skb_trim(skb, len);
 256                         break;
 257                 }
 258
 259                 if (len > CX82310_MTU) {
 260                         dev_err(&dev->udev->dev, "RX packet too long: %d B\n",
 261                                 len);
 262                         return 0;
 263                 }
 264
 265                 /* incomplete packet, save it for the next skb */
 266                 if (len > skb->len) {
 267                         dev->partial_len = skb->len;
 268                         dev->partial_rem = len - skb->len;
 269                         memcpy((void *)dev->partial_data, skb->data,
 270                                dev->partial_len);
 271                         skb_pull(skb, skb->len);
 272                         break;
 273                 }
 274
 275                 skb2 = alloc_skb(len, GFP_ATOMIC);
 276                 if (!skb2)
 277                         return 0;
 278                 skb_put(skb2, len);
 279                 memcpy(skb2->data, skb->data, len);
 280                 /* process the packet */
 281                 usbnet_skb_return(dev, skb2);
 282
 283                 skb_pull(skb, (len + 1) & ~1);
 284         }
 285
 286         /* let usbnet process the last packet */
 287         return 1;
 288 }
 289
 290 /* TX is easy, just add 2 bytes of length at the beginning */
 291 static struct sk_buff *cx82310_tx_fixup(struct usbnet *dev, struct sk_buff *skb,
 292                                        gfp_t flags)
 293 {
 294         int len = skb->len;
 295
 296         if (skb_headroom(skb) < 2) {
 297                 struct sk_buff *skb2 = skb_copy_expand(skb, 2, 0, flags);
 298                 dev_kfree_skb_any(skb);
 299                 skb = skb2;
 300                 if (!skb)
 301                         return NULL;
 302         }
 303         skb_push(skb, 2);
 304
 305         skb->data[0] = len;
 306         skb->data[1] = len >> 8;
 307
 308         return skb;
 309 }
 310
 311
 312 static const struct driver_info cx82310_info = {
 313         .description    = "Conexant CX82310 USB ethernet",
 314         .flags          = FLAG_ETHER,
 315         .bind           = cx82310_bind,
 316         .unbind         = cx82310_unbind,
 317         .rx_fixup       = cx82310_rx_fixup,
 318         .tx_fixup       = cx82310_tx_fixup,
 319 };
 320
 321 #define USB_DEVICE_CLASS(vend, prod, cl, sc, pr) \
 322         .match_flags = USB_DEVICE_ID_MATCH_DEVICE | \
 323                        USB_DEVICE_ID_MATCH_DEV_INFO, \
 324         .idVendor = (vend), \
 325         .idProduct = (prod), \
 326         .bDeviceClass = (cl), \
 327         .bDeviceSubClass = (sc), \
 328         .bDeviceProtocol = (pr)
 329
 330 static const struct usb_device_id products[] = {
 331         {
 332                 USB_DEVICE_CLASS(0x0572, 0xcb01, 0xff, 0, 0),
 333                 .driver_info = (unsigned long) &cx82310_info
 334         },
 335         { },
 336 };
 337 MODULE_DEVICE_TABLE(usb, products);
 338
 339 static struct usb_driver cx82310_driver = {
 340         .name           = "cx82310_eth",
 341         .id_table       = products,
 342         .probe          = usbnet_probe,
 343         .disconnect     = usbnet_disconnect,
 344         .suspend        = usbnet_suspend,
 345         .resume         = usbnet_resume,
 346         .disable_hub_initiated_lpm = 1,
 347 };
 348
 349 module_usb_driver(cx82310_driver);
 350
 351 MODULE_AUTHOR("Ondrej Zary");
 352 MODULE_DESCRIPTION("Conexant CX82310-based ADSL router USB ethernet driver");
 353 MODULE_LICENSE("GPL");