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 /* first command after power on can take around 8 seconds */
  50 #define CMD_TIMEOUT     15000
  51 #define CMD_REPLY_RETRY 5
  52
  53 #define CX82310_MTU     1514
  54 #define CMD_EP          0x01
  55
  56 /*
  57  * execute control command
  58  *  - optionally send some data (command parameters)
  59  *  - optionally wait for the reply
  60  *  - optionally read some data from the reply
  61  */
  62 static int cx82310_cmd(struct usbnet *dev, enum cx82310_cmd cmd, bool reply,
  63                        u8 *wdata, int wlen, u8 *rdata, int rlen)
  64 {
  65         int actual_len, retries, ret;
  66         struct usb_device *udev = dev->udev;
  67         u8 *buf = kzalloc(CMD_PACKET_SIZE, GFP_KERNEL);
  68
  69         if (!buf)
  70                 return -ENOMEM;
  71
  72         /* create command packet */
  73         buf[0] = cmd;
  74         if (wdata)
  75                 memcpy(buf + 4, wdata, min_t(int, wlen, CMD_PACKET_SIZE - 4));
  76
  77         /* send command packet */
  78         ret = usb_bulk_msg(udev, usb_sndbulkpipe(udev, CMD_EP), buf,
  79                            CMD_PACKET_SIZE, &actual_len, CMD_TIMEOUT);
  80         if (ret < 0) {
  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                                 dev_err(&dev->udev->dev,
  94                                         "reply receive error %d\n", ret);
  95                                 goto end;
  96                         }
  97                         if (actual_len > 0)
  98                                 break;
  99                 }
 100                 if (actual_len == 0) {
 101                         dev_err(&dev->udev->dev, "no reply to command %#x\n",
 102                                 cmd);
 103                         ret = -EIO;
 104                         goto end;
 105                 }
 106                 if (buf[0] != cmd) {
 107                         dev_err(&dev->udev->dev,
 108                                 "got reply to command %#x, expected: %#x\n",
 109                                 buf[0], cmd);
 110                         ret = -EIO;
 111                         goto end;
 112                 }
 113                 if (buf[1] != STATUS_SUCCESS) {
 114                         dev_err(&dev->udev->dev, "command %#x failed: %#x\n",
 115                                 cmd, buf[1]);
 116                         ret = -EIO;
 117                         goto end;
 118                 }
 119                 if (rdata)
 120                         memcpy(rdata, buf + 4,
 121                                min_t(int, rlen, CMD_PACKET_SIZE - 4));
 122         }
 123 end:
 124         kfree(buf);
 125         return ret;
 126 }
 127
 128 #define partial_len     data[0]         /* length of partial packet data */
 129 #define partial_rem     data[1]         /* remaining (missing) data length */
 130 #define partial_data    data[2]         /* partial packet data */
 131
 132 static int cx82310_bind(struct usbnet *dev, struct usb_interface *intf)
 133 {
 134         int ret;
 135         char buf[15];
 136         struct usb_device *udev = dev->udev;
 137
 138         /* avoid ADSL modems - continue only if iProduct is "USB NET CARD" */
 139         if (usb_string(udev, udev->descriptor.iProduct, buf, sizeof(buf)) > 0
 140             && strcmp(buf, "USB NET CARD")) {
 141                 dev_info(&udev->dev, "ignoring: probably an ADSL modem\n");
 142                 return -ENODEV;
 143         }
 144
 145         ret = usbnet_get_endpoints(dev, intf);
 146         if (ret)
 147                 return ret;
 148
 149         /*
 150          * this must not include ethernet header as the device can send partial
 151          * packets with no header (and sometimes even empty URBs)
 152          */
 153         dev->net->hard_header_len = 0;
 154         /* we can send at most 1514 bytes of data (+ 2-byte header) per URB */
 155         dev->hard_mtu = CX82310_MTU + 2;
 156         /* we can receive URBs up to 4KB from the device */
 157         dev->rx_urb_size = 4096;
 158
 159         dev->partial_data = (unsigned long) kmalloc(dev->hard_mtu, GFP_KERNEL);
 160         if (!dev->partial_data)
 161                 return -ENOMEM;
 162
 163         /* enable ethernet mode (?) */
 164         ret = cx82310_cmd(dev, CMD_ETHERNET_MODE, true, "\x01", 1, NULL, 0);
 165         if (ret) {
 166                 dev_err(&udev->dev, "unable to enable ethernet mode: %d\n",
 167                         ret);
 168                 goto err;
 169         }
 170
 171         /* get the MAC address */
 172         ret = cx82310_cmd(dev, CMD_GET_MAC_ADDR, true, NULL, 0,
 173                           dev->net->dev_addr, ETH_ALEN);
 174         if (ret) {
 175                 dev_err(&udev->dev, "unable to read MAC address: %d\n", ret);
 176                 goto err;
 177         }
 178
 179         /* start (does not seem to have any effect?) */
 180         ret = cx82310_cmd(dev, CMD_START, false, NULL, 0, NULL, 0);
 181         if (ret)
 182                 goto err;
 183
 184         return 0;
 185 err:
 186         kfree((void *)dev->partial_data);
 187         return ret;
 188 }
 189
 190 static void cx82310_unbind(struct usbnet *dev, struct usb_interface *intf)
 191 {
 192         kfree((void *)dev->partial_data);
 193 }
 194
 195 /*
 196  * RX is NOT easy - we can receive multiple packets per skb, each having 2-byte
 197  * packet length at the beginning.
 198  * The last packet might be incomplete (when it crosses the 4KB URB size),
 199  * continuing in the next skb (without any headers).
 200  * If a packet has odd length, there is one extra byte at the end (before next
 201  * packet or at the end of the URB).
 202  */
 203 static int cx82310_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
 204 {
 205         int len;
 206         struct sk_buff *skb2;
 207
 208         /*
 209          * If the last skb ended with an incomplete packet, this skb contains
 210          * end of that packet at the beginning.
 211          */
 212         if (dev->partial_rem) {
 213                 len = dev->partial_len + dev->partial_rem;
 214                 skb2 = alloc_skb(len, GFP_ATOMIC);
 215                 if (!skb2)
 216                         return 0;
 217                 skb_put(skb2, len);
 218                 memcpy(skb2->data, (void *)dev->partial_data,
 219                        dev->partial_len);
 220                 memcpy(skb2->data + dev->partial_len, skb->data,
 221                        dev->partial_rem);
 222                 usbnet_skb_return(dev, skb2);
 223                 skb_pull(skb, (dev->partial_rem + 1) & ~1);
 224                 dev->partial_rem = 0;
 225                 if (skb->len < 2)
 226                         return 1;
 227         }
 228
 229         /* a skb can contain multiple packets */
 230         while (skb->len > 1) {
 231                 /* first two bytes are packet length */
 232                 len = skb->data[0] | (skb->data[1] << 8);
 233                 skb_pull(skb, 2);
 234
 235                 /* if last packet in the skb, let usbnet to process it */
 236                 if (len == skb->len || len + 1 == skb->len) {
 237                         skb_trim(skb, len);
 238                         break;
 239                 }
 240
 241                 if (len > CX82310_MTU) {
 242                         dev_err(&dev->udev->dev, "RX packet too long: %d B\n",
 243                                 len);
 244                         return 0;
 245                 }
 246
 247                 /* incomplete packet, save it for the next skb */
 248                 if (len > skb->len) {
 249                         dev->partial_len = skb->len;
 250                         dev->partial_rem = len - skb->len;
 251                         memcpy((void *)dev->partial_data, skb->data,
 252                                dev->partial_len);
 253                         skb_pull(skb, skb->len);
 254                         break;
 255                 }
 256
 257                 skb2 = alloc_skb(len, GFP_ATOMIC);
 258                 if (!skb2)
 259                         return 0;
 260                 skb_put(skb2, len);
 261                 memcpy(skb2->data, skb->data, len);
 262                 /* process the packet */
 263                 usbnet_skb_return(dev, skb2);
 264
 265                 skb_pull(skb, (len + 1) & ~1);
 266         }
 267
 268         /* let usbnet process the last packet */
 269         return 1;
 270 }
 271
 272 /* TX is easy, just add 2 bytes of length at the beginning */
 273 static struct sk_buff *cx82310_tx_fixup(struct usbnet *dev, struct sk_buff *skb,
 274                                        gfp_t flags)
 275 {
 276         int len = skb->len;
 277
 278         if (skb_headroom(skb) < 2) {
 279                 struct sk_buff *skb2 = skb_copy_expand(skb, 2, 0, flags);
 280                 dev_kfree_skb_any(skb);
 281                 skb = skb2;
 282                 if (!skb)
 283                         return NULL;
 284         }
 285         skb_push(skb, 2);
 286
 287         skb->data[0] = len;
 288         skb->data[1] = len >> 8;
 289
 290         return skb;
 291 }
 292
 293
 294 static const struct driver_info cx82310_info = {
 295         .description    = "Conexant CX82310 USB ethernet",
 296         .flags          = FLAG_ETHER,
 297         .bind           = cx82310_bind,
 298         .unbind         = cx82310_unbind,
 299         .rx_fixup       = cx82310_rx_fixup,
 300         .tx_fixup       = cx82310_tx_fixup,
 301 };
 302
 303 static const struct usb_device_id products[] = {
 304         {
 305                 USB_DEVICE_AND_INTERFACE_INFO(0x0572, 0xcb01, 0xff, 0, 0),
 306                 .driver_info = (unsigned long) &cx82310_info
 307         },
 308         { },
 309 };
 310 MODULE_DEVICE_TABLE(usb, products);
 311
 312 static struct usb_driver cx82310_driver = {
 313         .name           = "cx82310_eth",
 314         .id_table       = products,
 315         .probe          = usbnet_probe,
 316         .disconnect     = usbnet_disconnect,
 317         .suspend        = usbnet_suspend,
 318         .resume         = usbnet_resume,
 319         .disable_hub_initiated_lpm = 1,
 320 };
 321
 322 module_usb_driver(cx82310_driver);
 323
 324 MODULE_AUTHOR("Ondrej Zary");
 325 MODULE_DESCRIPTION("Conexant CX82310-based ADSL router USB ethernet driver");
 326 MODULE_LICENSE("GPL");