drivers/net/usb/cx82310_eth.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Driver for USB ethernet port of Conexant CX82310-based ADSL routers
   4  * Copyright (C) 2010 by Ondrej Zary
   5  * some parts inspired by the cxacru driver
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/netdevice.h>
  10 #include <linux/etherdevice.h>
  11 #include <linux/ethtool.h>
  12 #include <linux/workqueue.h>
  13 #include <linux/mii.h>
  14 #include <linux/usb.h>
  15 #include <linux/usb/usbnet.h>
  16
  17 enum cx82310_cmd {
  18         CMD_START               = 0x84, /* no effect? */
  19         CMD_STOP                = 0x85, /* no effect? */
  20         CMD_GET_STATUS          = 0x90, /* returns nothing? */
  21         CMD_GET_MAC_ADDR        = 0x91, /* read MAC address */
  22         CMD_GET_LINK_STATUS     = 0x92, /* not useful, link is always up */
  23         CMD_ETHERNET_MODE       = 0x99, /* unknown, needed during init */
  24 };
  25
  26 enum cx82310_status {
  27         STATUS_UNDEFINED,
  28         STATUS_SUCCESS,
  29         STATUS_ERROR,
  30         STATUS_UNSUPPORTED,
  31         STATUS_UNIMPLEMENTED,
  32         STATUS_PARAMETER_ERROR,
  33         STATUS_DBG_LOOPBACK,
  34 };
  35
  36 #define CMD_PACKET_SIZE 64
  37 #define CMD_TIMEOUT     100
  38 #define CMD_REPLY_RETRY 5
  39
  40 #define CX82310_MTU     1514
  41 #define CMD_EP          0x01
  42
  43 struct cx82310_priv {
  44         struct work_struct reenable_work;
  45         struct usbnet *dev;
  46 };
  47
  48 /*
  49  * execute control command
  50  *  - optionally send some data (command parameters)
  51  *  - optionally wait for the reply
  52  *  - optionally read some data from the reply
  53  */
  54 static int cx82310_cmd(struct usbnet *dev, enum cx82310_cmd cmd, bool reply,
  55                        u8 *wdata, int wlen, u8 *rdata, int rlen)
  56 {
  57         int actual_len, retries, ret;
  58         struct usb_device *udev = dev->udev;
  59         u8 *buf = kzalloc(CMD_PACKET_SIZE, GFP_KERNEL);
  60
  61         if (!buf)
  62                 return -ENOMEM;
  63
  64         /* create command packet */
  65         buf[0] = cmd;
  66         if (wdata)
  67                 memcpy(buf + 4, wdata, min_t(int, wlen, CMD_PACKET_SIZE - 4));
  68
  69         /* send command packet */
  70         ret = usb_bulk_msg(udev, usb_sndbulkpipe(udev, CMD_EP), buf,
  71                            CMD_PACKET_SIZE, &actual_len, CMD_TIMEOUT);
  72         if (ret < 0) {
  73                 if (cmd != CMD_GET_LINK_STATUS)
  74                         netdev_err(dev->net, "send command %#x: error %d\n",
  75                                    cmd, ret);
  76                 goto end;
  77         }
  78
  79         if (reply) {
  80                 /* wait for reply, retry if it's empty */
  81                 for (retries = 0; retries < CMD_REPLY_RETRY; retries++) {
  82                         ret = usb_bulk_msg(udev, usb_rcvbulkpipe(udev, CMD_EP),
  83                                            buf, CMD_PACKET_SIZE, &actual_len,
  84                                            CMD_TIMEOUT);
  85                         if (ret < 0) {
  86                                 if (cmd != CMD_GET_LINK_STATUS)
  87                                         netdev_err(dev->net, "reply receive error %d\n",
  88                                                    ret);
  89                                 goto end;
  90                         }
  91                         if (actual_len > 0)
  92                                 break;
  93                 }
  94                 if (actual_len == 0) {
  95                         netdev_err(dev->net, "no reply to command %#x\n", cmd);
  96                         ret = -EIO;
  97                         goto end;
  98                 }
  99                 if (buf[0] != cmd) {
 100                         netdev_err(dev->net, "got reply to command %#x, expected: %#x\n",
 101                                    buf[0], cmd);
 102                         ret = -EIO;
 103                         goto end;
 104                 }
 105                 if (buf[1] != STATUS_SUCCESS) {
 106                         netdev_err(dev->net, "command %#x failed: %#x\n", cmd,
 107                                    buf[1]);
 108                         ret = -EIO;
 109                         goto end;
 110                 }
 111                 if (rdata)
 112                         memcpy(rdata, buf + 4,
 113                                min_t(int, rlen, CMD_PACKET_SIZE - 4));
 114         }
 115 end:
 116         kfree(buf);
 117         return ret;
 118 }
 119
 120 static int cx82310_enable_ethernet(struct usbnet *dev)
 121 {
 122         int ret = cx82310_cmd(dev, CMD_ETHERNET_MODE, true, "\x01", 1, NULL, 0);
 123
 124         if (ret)
 125                 netdev_err(dev->net, "unable to enable ethernet mode: %d\n",
 126                            ret);
 127         return ret;
 128 }
 129
 130 static void cx82310_reenable_work(struct work_struct *work)
 131 {
 132         struct cx82310_priv *priv = container_of(work, struct cx82310_priv,
 133                                                  reenable_work);
 134         cx82310_enable_ethernet(priv->dev);
 135 }
 136
 137 #define partial_len     data[0]         /* length of partial packet data */
 138 #define partial_rem     data[1]         /* remaining (missing) data length */
 139 #define partial_data    data[2]         /* partial packet data */
 140
 141 static int cx82310_bind(struct usbnet *dev, struct usb_interface *intf)
 142 {
 143         int ret;
 144         char buf[15];
 145         struct usb_device *udev = dev->udev;
 146         u8 link[3];
 147         int timeout = 50;
 148         struct cx82310_priv *priv;
 149
 150         /* avoid ADSL modems - continue only if iProduct is "USB NET CARD" */
 151         if (usb_string(udev, udev->descriptor.iProduct, buf, sizeof(buf)) > 0
 152             && strcmp(buf, "USB NET CARD")) {
 153                 dev_info(&udev->dev, "ignoring: probably an ADSL modem\n");
 154                 return -ENODEV;
 155         }
 156
 157         ret = usbnet_get_endpoints(dev, intf);
 158         if (ret)
 159                 return ret;
 160
 161         /*
 162          * this must not include ethernet header as the device can send partial
 163          * packets with no header (and sometimes even empty URBs)
 164          */
 165         dev->net->hard_header_len = 0;
 166         /* we can send at most 1514 bytes of data (+ 2-byte header) per URB */
 167         dev->hard_mtu = CX82310_MTU + 2;
 168         /* we can receive URBs up to 4KB from the device */
 169         dev->rx_urb_size = 4096;
 170
 171         dev->partial_data = (unsigned long) kmalloc(dev->hard_mtu, GFP_KERNEL);
 172         if (!dev->partial_data)
 173                 return -ENOMEM;
 174
 175         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 176         if (!priv) {
 177                 ret = -ENOMEM;
 178                 goto err_partial;
 179         }
 180         dev->driver_priv = priv;
 181         INIT_WORK(&priv->reenable_work, cx82310_reenable_work);
 182         priv->dev = dev;
 183
 184         /* wait for firmware to become ready (indicated by the link being up) */
 185         while (--timeout) {
 186                 ret = cx82310_cmd(dev, CMD_GET_LINK_STATUS, true, NULL, 0,
 187                                   link, sizeof(link));
 188                 /* the command can time out during boot - it's not an error */
 189                 if (!ret && link[0] == 1 && link[2] == 1)
 190                         break;
 191                 msleep(500);
 192         }
 193         if (!timeout) {
 194                 netdev_err(dev->net, "firmware not ready in time\n");
 195                 ret = -ETIMEDOUT;
 196                 goto err;
 197         }
 198
 199         /* enable ethernet mode (?) */
 200         ret = cx82310_enable_ethernet(dev);
 201         if (ret)
 202                 goto err;
 203
 204         /* get the MAC address */
 205         ret = cx82310_cmd(dev, CMD_GET_MAC_ADDR, true, NULL, 0,
 206                           dev->net->dev_addr, ETH_ALEN);
 207         if (ret) {
 208                 netdev_err(dev->net, "unable to read MAC address: %d\n", ret);
 209                 goto err;
 210         }
 211
 212         /* start (does not seem to have any effect?) */
 213         ret = cx82310_cmd(dev, CMD_START, false, NULL, 0, NULL, 0);
 214         if (ret)
 215                 goto err;
 216
 217         return 0;
 218 err:
 219         kfree(dev->driver_priv);
 220 err_partial:
 221         kfree((void *)dev->partial_data);
 222         return ret;
 223 }
 224
 225 static void cx82310_unbind(struct usbnet *dev, struct usb_interface *intf)
 226 {
 227         struct cx82310_priv *priv = dev->driver_priv;
 228
 229         kfree((void *)dev->partial_data);
 230         cancel_work_sync(&priv->reenable_work);
 231         kfree(dev->driver_priv);
 232 }
 233
 234 /*
 235  * RX is NOT easy - we can receive multiple packets per skb, each having 2-byte
 236  * packet length at the beginning.
 237  * The last packet might be incomplete (when it crosses the 4KB URB size),
 238  * continuing in the next skb (without any headers).
 239  * If a packet has odd length, there is one extra byte at the end (before next
 240  * packet or at the end of the URB).
 241  */
 242 static int cx82310_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
 243 {
 244         int len;
 245         struct sk_buff *skb2;
 246         struct cx82310_priv *priv = dev->driver_priv;
 247
 248         /*
 249          * If the last skb ended with an incomplete packet, this skb contains
 250          * end of that packet at the beginning.
 251          */
 252         if (dev->partial_rem) {
 253                 len = dev->partial_len + dev->partial_rem;
 254                 skb2 = alloc_skb(len, GFP_ATOMIC);
 255                 if (!skb2)
 256                         return 0;
 257                 skb_put(skb2, len);
 258                 memcpy(skb2->data, (void *)dev->partial_data,
 259                        dev->partial_len);
 260                 memcpy(skb2->data + dev->partial_len, skb->data,
 261                        dev->partial_rem);
 262                 usbnet_skb_return(dev, skb2);
 263                 skb_pull(skb, (dev->partial_rem + 1) & ~1);
 264                 dev->partial_rem = 0;
 265                 if (skb->len < 2)
 266                         return 1;
 267         }
 268
 269         /* a skb can contain multiple packets */
 270         while (skb->len > 1) {
 271                 /* first two bytes are packet length */
 272                 len = skb->data[0] | (skb->data[1] << 8);
 273                 skb_pull(skb, 2);
 274
 275                 /* if last packet in the skb, let usbnet to process it */
 276                 if (len == skb->len || len + 1 == skb->len) {
 277                         skb_trim(skb, len);
 278                         break;
 279                 }
 280
 281                 if (len == 0xffff) {
 282                         netdev_info(dev->net, "router was rebooted, re-enabling ethernet mode");
 283                         schedule_work(&priv->reenable_work);
 284                 } else if (len > CX82310_MTU) {
 285                         netdev_err(dev->net, "RX packet too long: %d B\n", len);
 286                         return 0;
 287                 }
 288
 289                 /* incomplete packet, save it for the next skb */
 290                 if (len > skb->len) {
 291                         dev->partial_len = skb->len;
 292                         dev->partial_rem = len - skb->len;
 293                         memcpy((void *)dev->partial_data, skb->data,
 294                                dev->partial_len);
 295                         skb_pull(skb, skb->len);
 296                         break;
 297                 }
 298
 299                 skb2 = alloc_skb(len, GFP_ATOMIC);
 300                 if (!skb2)
 301                         return 0;
 302                 skb_put(skb2, len);
 303                 memcpy(skb2->data, skb->data, len);
 304                 /* process the packet */
 305                 usbnet_skb_return(dev, skb2);
 306
 307                 skb_pull(skb, (len + 1) & ~1);
 308         }
 309
 310         /* let usbnet process the last packet */
 311         return 1;
 312 }
 313
 314 /* TX is easy, just add 2 bytes of length at the beginning */
 315 static struct sk_buff *cx82310_tx_fixup(struct usbnet *dev, struct sk_buff *skb,
 316                                        gfp_t flags)
 317 {
 318         int len = skb->len;
 319
 320         if (skb_cow_head(skb, 2)) {
 321                 dev_kfree_skb_any(skb);
 322                 return NULL;
 323         }
 324         skb_push(skb, 2);
 325
 326         skb->data[0] = len;
 327         skb->data[1] = len >> 8;
 328
 329         return skb;
 330 }
 331
 332
 333 static const struct driver_info cx82310_info = {
 334         .description    = "Conexant CX82310 USB ethernet",
 335         .flags          = FLAG_ETHER,
 336         .bind           = cx82310_bind,
 337         .unbind         = cx82310_unbind,
 338         .rx_fixup       = cx82310_rx_fixup,
 339         .tx_fixup       = cx82310_tx_fixup,
 340 };
 341
 342 #define USB_DEVICE_CLASS(vend, prod, cl, sc, pr) \
 343         .match_flags = USB_DEVICE_ID_MATCH_DEVICE | \
 344                        USB_DEVICE_ID_MATCH_DEV_INFO, \
 345         .idVendor = (vend), \
 346         .idProduct = (prod), \
 347         .bDeviceClass = (cl), \
 348         .bDeviceSubClass = (sc), \
 349         .bDeviceProtocol = (pr)
 350
 351 static const struct usb_device_id products[] = {
 352         {
 353                 USB_DEVICE_CLASS(0x0572, 0xcb01, 0xff, 0, 0),
 354                 .driver_info = (unsigned long) &cx82310_info
 355         },
 356         { },
 357 };
 358 MODULE_DEVICE_TABLE(usb, products);
 359
 360 static struct usb_driver cx82310_driver = {
 361         .name           = "cx82310_eth",
 362         .id_table       = products,
 363         .probe          = usbnet_probe,
 364         .disconnect     = usbnet_disconnect,
 365         .suspend        = usbnet_suspend,
 366         .resume         = usbnet_resume,
 367         .disable_hub_initiated_lpm = 1,
 368 };
 369
 370 module_usb_driver(cx82310_driver);
 371
 372 MODULE_AUTHOR("Ondrej Zary");
 373 MODULE_DESCRIPTION("Conexant CX82310-based ADSL router USB ethernet driver");
 374 MODULE_LICENSE("GPL");