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         u8 addr[ETH_ALEN];
 150
 151         /* avoid ADSL modems - continue only if iProduct is "USB NET CARD" */
 152         if (usb_string(udev, udev->descriptor.iProduct, buf, sizeof(buf)) > 0
 153             && strcmp(buf, "USB NET CARD")) {
 154                 dev_info(&udev->dev, "ignoring: probably an ADSL modem\n");
 155                 return -ENODEV;
 156         }
 157
 158         ret = usbnet_get_endpoints(dev, intf);
 159         if (ret)
 160                 return ret;
 161
 162         /*
 163          * this must not include ethernet header as the device can send partial
 164          * packets with no header (and sometimes even empty URBs)
 165          */
 166         dev->net->hard_header_len = 0;
 167         /* we can send at most 1514 bytes of data (+ 2-byte header) per URB */
 168         dev->hard_mtu = CX82310_MTU + 2;
 169         /* we can receive URBs up to 4KB from the device */
 170         dev->rx_urb_size = 4096;
 171
 172         dev->partial_data = (unsigned long) kmalloc(dev->hard_mtu, GFP_KERNEL);
 173         if (!dev->partial_data)
 174                 return -ENOMEM;
 175
 176         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 177         if (!priv) {
 178                 ret = -ENOMEM;
 179                 goto err_partial;
 180         }
 181         dev->driver_priv = priv;
 182         INIT_WORK(&priv->reenable_work, cx82310_reenable_work);
 183         priv->dev = dev;
 184
 185         /* wait for firmware to become ready (indicated by the link being up) */
 186         while (--timeout) {
 187                 ret = cx82310_cmd(dev, CMD_GET_LINK_STATUS, true, NULL, 0,
 188                                   link, sizeof(link));
 189                 /* the command can time out during boot - it's not an error */
 190                 if (!ret && link[0] == 1 && link[2] == 1)
 191                         break;
 192                 msleep(500);
 193         }
 194         if (!timeout) {
 195                 netdev_err(dev->net, "firmware not ready in time\n");
 196                 ret = -ETIMEDOUT;
 197                 goto err;
 198         }
 199
 200         /* enable ethernet mode (?) */
 201         ret = cx82310_enable_ethernet(dev);
 202         if (ret)
 203                 goto err;
 204
 205         /* get the MAC address */
 206         ret = cx82310_cmd(dev, CMD_GET_MAC_ADDR, true, NULL, 0, addr, ETH_ALEN);
 207         if (ret) {
 208                 netdev_err(dev->net, "unable to read MAC address: %d\n", ret);
 209                 goto err;
 210         }
 211         eth_hw_addr_set(dev->net, addr);
 212
 213         /* start (does not seem to have any effect?) */
 214         ret = cx82310_cmd(dev, CMD_START, false, NULL, 0, NULL, 0);
 215         if (ret)
 216                 goto err;
 217
 218         return 0;
 219 err:
 220         kfree(dev->driver_priv);
 221 err_partial:
 222         kfree((void *)dev->partial_data);
 223         return ret;
 224 }
 225
 226 static void cx82310_unbind(struct usbnet *dev, struct usb_interface *intf)
 227 {
 228         struct cx82310_priv *priv = dev->driver_priv;
 229
 230         kfree((void *)dev->partial_data);
 231         cancel_work_sync(&priv->reenable_work);
 232         kfree(dev->driver_priv);
 233 }
 234
 235 /*
 236  * RX is NOT easy - we can receive multiple packets per skb, each having 2-byte
 237  * packet length at the beginning.
 238  * The last packet might be incomplete (when it crosses the 4KB URB size),
 239  * continuing in the next skb (without any headers).
 240  * If a packet has odd length, there is one extra byte at the end (before next
 241  * packet or at the end of the URB).
 242  */
 243 static int cx82310_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
 244 {
 245         int len;
 246         struct sk_buff *skb2;
 247         struct cx82310_priv *priv = dev->driver_priv;
 248
 249         /*
 250          * If the last skb ended with an incomplete packet, this skb contains
 251          * end of that packet at the beginning.
 252          */
 253         if (dev->partial_rem) {
 254                 len = dev->partial_len + dev->partial_rem;
 255                 skb2 = alloc_skb(len, GFP_ATOMIC);
 256                 if (!skb2)
 257                         return 0;
 258                 skb_put(skb2, len);
 259                 memcpy(skb2->data, (void *)dev->partial_data,
 260                        dev->partial_len);
 261                 memcpy(skb2->data + dev->partial_len, skb->data,
 262                        dev->partial_rem);
 263                 usbnet_skb_return(dev, skb2);
 264                 skb_pull(skb, (dev->partial_rem + 1) & ~1);
 265                 dev->partial_rem = 0;
 266                 if (skb->len < 2)
 267                         return 1;
 268         }
 269
 270         /* a skb can contain multiple packets */
 271         while (skb->len > 1) {
 272                 /* first two bytes are packet length */
 273                 len = skb->data[0] | (skb->data[1] << 8);
 274                 skb_pull(skb, 2);
 275
 276                 /* if last packet in the skb, let usbnet to process it */
 277                 if (len == skb->len || len + 1 == skb->len) {
 278                         skb_trim(skb, len);
 279                         break;
 280                 }
 281
 282                 if (len == 0xffff) {
 283                         netdev_info(dev->net, "router was rebooted, re-enabling ethernet mode");
 284                         schedule_work(&priv->reenable_work);
 285                 } else if (len > CX82310_MTU) {
 286                         netdev_err(dev->net, "RX packet too long: %d B\n", len);
 287                         return 0;
 288                 }
 289
 290                 /* incomplete packet, save it for the next skb */
 291                 if (len > skb->len) {
 292                         dev->partial_len = skb->len;
 293                         dev->partial_rem = len - skb->len;
 294                         memcpy((void *)dev->partial_data, skb->data,
 295                                dev->partial_len);
 296                         skb_pull(skb, skb->len);
 297                         break;
 298                 }
 299
 300                 skb2 = alloc_skb(len, GFP_ATOMIC);
 301                 if (!skb2)
 302                         return 0;
 303                 skb_put(skb2, len);
 304                 memcpy(skb2->data, skb->data, len);
 305                 /* process the packet */
 306                 usbnet_skb_return(dev, skb2);
 307
 308                 skb_pull(skb, (len + 1) & ~1);
 309         }
 310
 311         /* let usbnet process the last packet */
 312         return 1;
 313 }
 314
 315 /* TX is easy, just add 2 bytes of length at the beginning */
 316 static struct sk_buff *cx82310_tx_fixup(struct usbnet *dev, struct sk_buff *skb,
 317                                        gfp_t flags)
 318 {
 319         int len = skb->len;
 320
 321         if (skb_cow_head(skb, 2)) {
 322                 dev_kfree_skb_any(skb);
 323                 return NULL;
 324         }
 325         skb_push(skb, 2);
 326
 327         skb->data[0] = len;
 328         skb->data[1] = len >> 8;
 329
 330         return skb;
 331 }
 332
 333
 334 static const struct driver_info cx82310_info = {
 335         .description    = "Conexant CX82310 USB ethernet",
 336         .flags          = FLAG_ETHER,
 337         .bind           = cx82310_bind,
 338         .unbind         = cx82310_unbind,
 339         .rx_fixup       = cx82310_rx_fixup,
 340         .tx_fixup       = cx82310_tx_fixup,
 341 };
 342
 343 #define USB_DEVICE_CLASS(vend, prod, cl, sc, pr) \
 344         .match_flags = USB_DEVICE_ID_MATCH_DEVICE | \
 345                        USB_DEVICE_ID_MATCH_DEV_INFO, \
 346         .idVendor = (vend), \
 347         .idProduct = (prod), \
 348         .bDeviceClass = (cl), \
 349         .bDeviceSubClass = (sc), \
 350         .bDeviceProtocol = (pr)
 351
 352 static const struct usb_device_id products[] = {
 353         {
 354                 USB_DEVICE_CLASS(0x0572, 0xcb01, 0xff, 0, 0),
 355                 .driver_info = (unsigned long) &cx82310_info
 356         },
 357         { },
 358 };
 359 MODULE_DEVICE_TABLE(usb, products);
 360
 361 static struct usb_driver cx82310_driver = {
 362         .name           = "cx82310_eth",
 363         .id_table       = products,
 364         .probe          = usbnet_probe,
 365         .disconnect     = usbnet_disconnect,
 366         .suspend        = usbnet_suspend,
 367         .resume         = usbnet_resume,
 368         .disable_hub_initiated_lpm = 1,
 369 };
 370
 371 module_usb_driver(cx82310_driver);
 372
 373 MODULE_AUTHOR("Ondrej Zary");
 374 MODULE_DESCRIPTION("Conexant CX82310-based ADSL router USB ethernet driver");
 375 MODULE_LICENSE("GPL");