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