linux/drivers/net/can/usb/usb_8dev.c
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   1/*
   2 * CAN driver for "8 devices" USB2CAN converter
   3 *
   4 * Copyright (C) 2012 Bernd Krumboeck (krumboeck@universalnet.at)
   5 *
   6 * This program is free software; you can redistribute it and/or modify it
   7 * under the terms of the GNU General Public License as published
   8 * by the Free Software Foundation; version 2 of the License.
   9 *
  10 * This program is distributed in the hope that it will be useful, but
  11 * WITHOUT ANY WARRANTY; without even the implied warranty of
  12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13 * General Public License for more details.
  14 *
  15 * You should have received a copy of the GNU General Public License along
  16 * with this program.
  17 *
  18 * This driver is inspired by the 3.2.0 version of drivers/net/can/usb/ems_usb.c
  19 * and drivers/net/can/usb/esd_usb2.c
  20 *
  21 * Many thanks to Gerhard Bertelsmann (info@gerhard-bertelsmann.de)
  22 * for testing and fixing this driver. Also many thanks to "8 devices",
  23 * who were very cooperative and answered my questions.
  24 */
  25
  26#include <linux/signal.h>
  27#include <linux/slab.h>
  28#include <linux/module.h>
  29#include <linux/netdevice.h>
  30#include <linux/usb.h>
  31
  32#include <linux/can.h>
  33#include <linux/can/dev.h>
  34#include <linux/can/error.h>
  35#include <linux/can/led.h>
  36
  37/* driver constants */
  38#define MAX_RX_URBS                     20
  39#define MAX_TX_URBS                     20
  40#define RX_BUFFER_SIZE                  64
  41
  42/* vendor and product id */
  43#define USB_8DEV_VENDOR_ID              0x0483
  44#define USB_8DEV_PRODUCT_ID             0x1234
  45
  46/* endpoints */
  47enum usb_8dev_endpoint {
  48        USB_8DEV_ENDP_DATA_RX = 1,
  49        USB_8DEV_ENDP_DATA_TX,
  50        USB_8DEV_ENDP_CMD_RX,
  51        USB_8DEV_ENDP_CMD_TX
  52};
  53
  54/* device CAN clock */
  55#define USB_8DEV_ABP_CLOCK              32000000
  56
  57/* setup flags */
  58#define USB_8DEV_SILENT                 0x01
  59#define USB_8DEV_LOOPBACK               0x02
  60#define USB_8DEV_DISABLE_AUTO_RESTRANS  0x04
  61#define USB_8DEV_STATUS_FRAME           0x08
  62
  63/* commands */
  64enum usb_8dev_cmd {
  65        USB_8DEV_RESET = 1,
  66        USB_8DEV_OPEN,
  67        USB_8DEV_CLOSE,
  68        USB_8DEV_SET_SPEED,
  69        USB_8DEV_SET_MASK_FILTER,
  70        USB_8DEV_GET_STATUS,
  71        USB_8DEV_GET_STATISTICS,
  72        USB_8DEV_GET_SERIAL,
  73        USB_8DEV_GET_SOFTW_VER,
  74        USB_8DEV_GET_HARDW_VER,
  75        USB_8DEV_RESET_TIMESTAMP,
  76        USB_8DEV_GET_SOFTW_HARDW_VER
  77};
  78
  79/* command options */
  80#define USB_8DEV_BAUD_MANUAL            0x09
  81#define USB_8DEV_CMD_START              0x11
  82#define USB_8DEV_CMD_END                0x22
  83
  84#define USB_8DEV_CMD_SUCCESS            0
  85#define USB_8DEV_CMD_ERROR              255
  86
  87#define USB_8DEV_CMD_TIMEOUT            1000
  88
  89/* frames */
  90#define USB_8DEV_DATA_START             0x55
  91#define USB_8DEV_DATA_END               0xAA
  92
  93#define USB_8DEV_TYPE_CAN_FRAME         0
  94#define USB_8DEV_TYPE_ERROR_FRAME       3
  95
  96#define USB_8DEV_EXTID                  0x01
  97#define USB_8DEV_RTR                    0x02
  98#define USB_8DEV_ERR_FLAG               0x04
  99
 100/* status */
 101#define USB_8DEV_STATUSMSG_OK           0x00  /* Normal condition. */
 102#define USB_8DEV_STATUSMSG_OVERRUN      0x01  /* Overrun occured when sending */
 103#define USB_8DEV_STATUSMSG_BUSLIGHT     0x02  /* Error counter has reached 96 */
 104#define USB_8DEV_STATUSMSG_BUSHEAVY     0x03  /* Error count. has reached 128 */
 105#define USB_8DEV_STATUSMSG_BUSOFF       0x04  /* Device is in BUSOFF */
 106#define USB_8DEV_STATUSMSG_STUFF        0x20  /* Stuff Error */
 107#define USB_8DEV_STATUSMSG_FORM         0x21  /* Form Error */
 108#define USB_8DEV_STATUSMSG_ACK          0x23  /* Ack Error */
 109#define USB_8DEV_STATUSMSG_BIT0         0x24  /* Bit1 Error */
 110#define USB_8DEV_STATUSMSG_BIT1         0x25  /* Bit0 Error */
 111#define USB_8DEV_STATUSMSG_CRC          0x27  /* CRC Error */
 112
 113#define USB_8DEV_RP_MASK                0x7F  /* Mask for Receive Error Bit */
 114
 115
 116/* table of devices that work with this driver */
 117static const struct usb_device_id usb_8dev_table[] = {
 118        { USB_DEVICE(USB_8DEV_VENDOR_ID, USB_8DEV_PRODUCT_ID) },
 119        { }                                     /* Terminating entry */
 120};
 121
 122MODULE_DEVICE_TABLE(usb, usb_8dev_table);
 123
 124struct usb_8dev_tx_urb_context {
 125        struct usb_8dev_priv *priv;
 126
 127        u32 echo_index;
 128        u8 dlc;
 129};
 130
 131/* Structure to hold all of our device specific stuff */
 132struct usb_8dev_priv {
 133        struct can_priv can; /* must be the first member */
 134
 135        struct sk_buff *echo_skb[MAX_TX_URBS];
 136
 137        struct usb_device *udev;
 138        struct net_device *netdev;
 139
 140        atomic_t active_tx_urbs;
 141        struct usb_anchor tx_submitted;
 142        struct usb_8dev_tx_urb_context tx_contexts[MAX_TX_URBS];
 143
 144        struct usb_anchor rx_submitted;
 145
 146        struct can_berr_counter bec;
 147
 148        u8 *cmd_msg_buffer;
 149
 150        struct mutex usb_8dev_cmd_lock;
 151
 152};
 153
 154/* tx frame */
 155struct __packed usb_8dev_tx_msg {
 156        u8 begin;
 157        u8 flags;       /* RTR and EXT_ID flag */
 158        __be32 id;      /* upper 3 bits not used */
 159        u8 dlc;         /* data length code 0-8 bytes */
 160        u8 data[8];     /* 64-bit data */
 161        u8 end;
 162};
 163
 164/* rx frame */
 165struct __packed usb_8dev_rx_msg {
 166        u8 begin;
 167        u8 type;                /* frame type */
 168        u8 flags;               /* RTR and EXT_ID flag */
 169        __be32 id;              /* upper 3 bits not used */
 170        u8 dlc;                 /* data length code 0-8 bytes */
 171        u8 data[8];             /* 64-bit data */
 172        __be32 timestamp;       /* 32-bit timestamp */
 173        u8 end;
 174};
 175
 176/* command frame */
 177struct __packed usb_8dev_cmd_msg {
 178        u8 begin;
 179        u8 channel;     /* unkown - always 0 */
 180        u8 command;     /* command to execute */
 181        u8 opt1;        /* optional parameter / return value */
 182        u8 opt2;        /* optional parameter 2 */
 183        u8 data[10];    /* optional parameter and data */
 184        u8 end;
 185};
 186
 187static int usb_8dev_send_cmd_msg(struct usb_8dev_priv *priv, u8 *msg, int size)
 188{
 189        int actual_length;
 190
 191        return usb_bulk_msg(priv->udev,
 192                            usb_sndbulkpipe(priv->udev, USB_8DEV_ENDP_CMD_TX),
 193                            msg, size, &actual_length, USB_8DEV_CMD_TIMEOUT);
 194}
 195
 196static int usb_8dev_wait_cmd_msg(struct usb_8dev_priv *priv, u8 *msg, int size,
 197                                int *actual_length)
 198{
 199        return usb_bulk_msg(priv->udev,
 200                            usb_rcvbulkpipe(priv->udev, USB_8DEV_ENDP_CMD_RX),
 201                            msg, size, actual_length, USB_8DEV_CMD_TIMEOUT);
 202}
 203
 204/* Send command to device and receive result.
 205 * Command was successful when opt1 = 0.
 206 */
 207static int usb_8dev_send_cmd(struct usb_8dev_priv *priv,
 208                             struct usb_8dev_cmd_msg *out,
 209                             struct usb_8dev_cmd_msg *in)
 210{
 211        int err;
 212        int num_bytes_read;
 213        struct net_device *netdev;
 214
 215        netdev = priv->netdev;
 216
 217        out->begin = USB_8DEV_CMD_START;
 218        out->end = USB_8DEV_CMD_END;
 219
 220        mutex_lock(&priv->usb_8dev_cmd_lock);
 221
 222        memcpy(priv->cmd_msg_buffer, out,
 223                sizeof(struct usb_8dev_cmd_msg));
 224
 225        err = usb_8dev_send_cmd_msg(priv, priv->cmd_msg_buffer,
 226                                    sizeof(struct usb_8dev_cmd_msg));
 227        if (err < 0) {
 228                netdev_err(netdev, "sending command message failed\n");
 229                goto failed;
 230        }
 231
 232        err = usb_8dev_wait_cmd_msg(priv, priv->cmd_msg_buffer,
 233                                    sizeof(struct usb_8dev_cmd_msg),
 234                                    &num_bytes_read);
 235        if (err < 0) {
 236                netdev_err(netdev, "no command message answer\n");
 237                goto failed;
 238        }
 239
 240        memcpy(in, priv->cmd_msg_buffer, sizeof(struct usb_8dev_cmd_msg));
 241
 242        if (in->begin != USB_8DEV_CMD_START || in->end != USB_8DEV_CMD_END ||
 243                        num_bytes_read != 16 || in->opt1 != 0)
 244                err = -EPROTO;
 245
 246failed:
 247        mutex_unlock(&priv->usb_8dev_cmd_lock);
 248        return err;
 249}
 250
 251/* Send open command to device */
 252static int usb_8dev_cmd_open(struct usb_8dev_priv *priv)
 253{
 254        struct can_bittiming *bt = &priv->can.bittiming;
 255        struct usb_8dev_cmd_msg outmsg;
 256        struct usb_8dev_cmd_msg inmsg;
 257        u32 ctrlmode = priv->can.ctrlmode;
 258        u32 flags = USB_8DEV_STATUS_FRAME;
 259        __be32 beflags;
 260        __be16 bebrp;
 261
 262        memset(&outmsg, 0, sizeof(outmsg));
 263        outmsg.command = USB_8DEV_OPEN;
 264        outmsg.opt1 = USB_8DEV_BAUD_MANUAL;
 265        outmsg.data[0] = bt->prop_seg + bt->phase_seg1;
 266        outmsg.data[1] = bt->phase_seg2;
 267        outmsg.data[2] = bt->sjw;
 268
 269        /* BRP */
 270        bebrp = cpu_to_be16((u16)bt->brp);
 271        memcpy(&outmsg.data[3], &bebrp, sizeof(bebrp));
 272
 273        /* flags */
 274        if (ctrlmode & CAN_CTRLMODE_LOOPBACK)
 275                flags |= USB_8DEV_LOOPBACK;
 276        if (ctrlmode & CAN_CTRLMODE_LISTENONLY)
 277                flags |= USB_8DEV_SILENT;
 278        if (ctrlmode & CAN_CTRLMODE_ONE_SHOT)
 279                flags |= USB_8DEV_DISABLE_AUTO_RESTRANS;
 280
 281        beflags = cpu_to_be32(flags);
 282        memcpy(&outmsg.data[5], &beflags, sizeof(beflags));
 283
 284        return usb_8dev_send_cmd(priv, &outmsg, &inmsg);
 285}
 286
 287/* Send close command to device */
 288static int usb_8dev_cmd_close(struct usb_8dev_priv *priv)
 289{
 290        struct usb_8dev_cmd_msg inmsg;
 291        struct usb_8dev_cmd_msg outmsg = {
 292                .channel = 0,
 293                .command = USB_8DEV_CLOSE,
 294                .opt1 = 0,
 295                .opt2 = 0
 296        };
 297
 298        return usb_8dev_send_cmd(priv, &outmsg, &inmsg);
 299}
 300
 301/* Get firmware and hardware version */
 302static int usb_8dev_cmd_version(struct usb_8dev_priv *priv, u32 *res)
 303{
 304        struct usb_8dev_cmd_msg inmsg;
 305        struct usb_8dev_cmd_msg outmsg = {
 306                .channel = 0,
 307                .command = USB_8DEV_GET_SOFTW_HARDW_VER,
 308                .opt1 = 0,
 309                .opt2 = 0
 310        };
 311
 312        int err = usb_8dev_send_cmd(priv, &outmsg, &inmsg);
 313        if (err)
 314                return err;
 315
 316        *res = be32_to_cpup((__be32 *)inmsg.data);
 317
 318        return err;
 319}
 320
 321/* Set network device mode
 322 *
 323 * Maybe we should leave this function empty, because the device
 324 * set mode variable with open command.
 325 */
 326static int usb_8dev_set_mode(struct net_device *netdev, enum can_mode mode)
 327{
 328        struct usb_8dev_priv *priv = netdev_priv(netdev);
 329        int err = 0;
 330
 331        switch (mode) {
 332        case CAN_MODE_START:
 333                err = usb_8dev_cmd_open(priv);
 334                if (err)
 335                        netdev_warn(netdev, "couldn't start device");
 336                break;
 337
 338        default:
 339                return -EOPNOTSUPP;
 340        }
 341
 342        return err;
 343}
 344
 345/* Read error/status frames */
 346static void usb_8dev_rx_err_msg(struct usb_8dev_priv *priv,
 347                                struct usb_8dev_rx_msg *msg)
 348{
 349        struct can_frame *cf;
 350        struct sk_buff *skb;
 351        struct net_device_stats *stats = &priv->netdev->stats;
 352
 353        /* Error message:
 354         * byte 0: Status
 355         * byte 1: bit   7: Receive Passive
 356         * byte 1: bit 0-6: Receive Error Counter
 357         * byte 2: Transmit Error Counter
 358         * byte 3: Always 0 (maybe reserved for future use)
 359         */
 360
 361        u8 state = msg->data[0];
 362        u8 rxerr = msg->data[1] & USB_8DEV_RP_MASK;
 363        u8 txerr = msg->data[2];
 364        int rx_errors = 0;
 365        int tx_errors = 0;
 366
 367        skb = alloc_can_err_skb(priv->netdev, &cf);
 368        if (!skb)
 369                return;
 370
 371        switch (state) {
 372        case USB_8DEV_STATUSMSG_OK:
 373                priv->can.state = CAN_STATE_ERROR_ACTIVE;
 374                cf->can_id |= CAN_ERR_PROT;
 375                cf->data[2] = CAN_ERR_PROT_ACTIVE;
 376                break;
 377        case USB_8DEV_STATUSMSG_BUSOFF:
 378                priv->can.state = CAN_STATE_BUS_OFF;
 379                cf->can_id |= CAN_ERR_BUSOFF;
 380                can_bus_off(priv->netdev);
 381                break;
 382        case USB_8DEV_STATUSMSG_OVERRUN:
 383        case USB_8DEV_STATUSMSG_BUSLIGHT:
 384        case USB_8DEV_STATUSMSG_BUSHEAVY:
 385                cf->can_id |= CAN_ERR_CRTL;
 386                break;
 387        default:
 388                priv->can.state = CAN_STATE_ERROR_WARNING;
 389                cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
 390                priv->can.can_stats.bus_error++;
 391                break;
 392        }
 393
 394        switch (state) {
 395        case USB_8DEV_STATUSMSG_OK:
 396        case USB_8DEV_STATUSMSG_BUSOFF:
 397                break;
 398        case USB_8DEV_STATUSMSG_ACK:
 399                cf->can_id |= CAN_ERR_ACK;
 400                tx_errors = 1;
 401                break;
 402        case USB_8DEV_STATUSMSG_CRC:
 403                cf->data[2] |= CAN_ERR_PROT_UNSPEC;
 404                cf->data[3] |= CAN_ERR_PROT_LOC_CRC_SEQ |
 405                               CAN_ERR_PROT_LOC_CRC_DEL;
 406                rx_errors = 1;
 407                break;
 408        case USB_8DEV_STATUSMSG_BIT0:
 409                cf->data[2] |= CAN_ERR_PROT_BIT0;
 410                tx_errors = 1;
 411                break;
 412        case USB_8DEV_STATUSMSG_BIT1:
 413                cf->data[2] |= CAN_ERR_PROT_BIT1;
 414                tx_errors = 1;
 415                break;
 416        case USB_8DEV_STATUSMSG_FORM:
 417                cf->data[2] |= CAN_ERR_PROT_FORM;
 418                rx_errors = 1;
 419                break;
 420        case USB_8DEV_STATUSMSG_STUFF:
 421                cf->data[2] |= CAN_ERR_PROT_STUFF;
 422                rx_errors = 1;
 423                break;
 424        case USB_8DEV_STATUSMSG_OVERRUN:
 425                cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
 426                stats->rx_over_errors++;
 427                rx_errors = 1;
 428                break;
 429        case USB_8DEV_STATUSMSG_BUSLIGHT:
 430                priv->can.state = CAN_STATE_ERROR_WARNING;
 431                cf->data[1] = (txerr > rxerr) ?
 432                        CAN_ERR_CRTL_TX_WARNING :
 433                        CAN_ERR_CRTL_RX_WARNING;
 434                priv->can.can_stats.error_warning++;
 435                break;
 436        case USB_8DEV_STATUSMSG_BUSHEAVY:
 437                priv->can.state = CAN_STATE_ERROR_PASSIVE;
 438                cf->data[1] = (txerr > rxerr) ?
 439                        CAN_ERR_CRTL_TX_PASSIVE :
 440                        CAN_ERR_CRTL_RX_PASSIVE;
 441                priv->can.can_stats.error_passive++;
 442                break;
 443        default:
 444                netdev_warn(priv->netdev,
 445                            "Unknown status/error message (%d)\n", state);
 446                break;
 447        }
 448
 449        if (tx_errors) {
 450                cf->data[2] |= CAN_ERR_PROT_TX;
 451                stats->tx_errors++;
 452        }
 453
 454        if (rx_errors)
 455                stats->rx_errors++;
 456
 457        cf->data[6] = txerr;
 458        cf->data[7] = rxerr;
 459
 460        priv->bec.txerr = txerr;
 461        priv->bec.rxerr = rxerr;
 462
 463        netif_rx(skb);
 464
 465        stats->rx_packets++;
 466        stats->rx_bytes += cf->can_dlc;
 467}
 468
 469/* Read data and status frames */
 470static void usb_8dev_rx_can_msg(struct usb_8dev_priv *priv,
 471                                struct usb_8dev_rx_msg *msg)
 472{
 473        struct can_frame *cf;
 474        struct sk_buff *skb;
 475        struct net_device_stats *stats = &priv->netdev->stats;
 476
 477        if (msg->type == USB_8DEV_TYPE_ERROR_FRAME &&
 478                   msg->flags == USB_8DEV_ERR_FLAG) {
 479                usb_8dev_rx_err_msg(priv, msg);
 480        } else if (msg->type == USB_8DEV_TYPE_CAN_FRAME) {
 481                skb = alloc_can_skb(priv->netdev, &cf);
 482                if (!skb)
 483                        return;
 484
 485                cf->can_id = be32_to_cpu(msg->id);
 486                cf->can_dlc = get_can_dlc(msg->dlc & 0xF);
 487
 488                if (msg->flags & USB_8DEV_EXTID)
 489                        cf->can_id |= CAN_EFF_FLAG;
 490
 491                if (msg->flags & USB_8DEV_RTR)
 492                        cf->can_id |= CAN_RTR_FLAG;
 493                else
 494                        memcpy(cf->data, msg->data, cf->can_dlc);
 495
 496                netif_rx(skb);
 497
 498                stats->rx_packets++;
 499                stats->rx_bytes += cf->can_dlc;
 500
 501                can_led_event(priv->netdev, CAN_LED_EVENT_RX);
 502        } else {
 503                netdev_warn(priv->netdev, "frame type %d unknown",
 504                         msg->type);
 505        }
 506
 507}
 508
 509/* Callback for reading data from device
 510 *
 511 * Check urb status, call read function and resubmit urb read operation.
 512 */
 513static void usb_8dev_read_bulk_callback(struct urb *urb)
 514{
 515        struct usb_8dev_priv *priv = urb->context;
 516        struct net_device *netdev;
 517        int retval;
 518        int pos = 0;
 519
 520        netdev = priv->netdev;
 521
 522        if (!netif_device_present(netdev))
 523                return;
 524
 525        switch (urb->status) {
 526        case 0: /* success */
 527                break;
 528
 529        case -ENOENT:
 530        case -ESHUTDOWN:
 531                return;
 532
 533        default:
 534                netdev_info(netdev, "Rx URB aborted (%d)\n",
 535                         urb->status);
 536                goto resubmit_urb;
 537        }
 538
 539        while (pos < urb->actual_length) {
 540                struct usb_8dev_rx_msg *msg;
 541
 542                if (pos + sizeof(struct usb_8dev_rx_msg) > urb->actual_length) {
 543                        netdev_err(priv->netdev, "format error\n");
 544                        break;
 545                }
 546
 547                msg = (struct usb_8dev_rx_msg *)(urb->transfer_buffer + pos);
 548                usb_8dev_rx_can_msg(priv, msg);
 549
 550                pos += sizeof(struct usb_8dev_rx_msg);
 551        }
 552
 553resubmit_urb:
 554        usb_fill_bulk_urb(urb, priv->udev,
 555                          usb_rcvbulkpipe(priv->udev, USB_8DEV_ENDP_DATA_RX),
 556                          urb->transfer_buffer, RX_BUFFER_SIZE,
 557                          usb_8dev_read_bulk_callback, priv);
 558
 559        retval = usb_submit_urb(urb, GFP_ATOMIC);
 560
 561        if (retval == -ENODEV)
 562                netif_device_detach(netdev);
 563        else if (retval)
 564                netdev_err(netdev,
 565                        "failed resubmitting read bulk urb: %d\n", retval);
 566}
 567
 568/* Callback handler for write operations
 569 *
 570 * Free allocated buffers, check transmit status and
 571 * calculate statistic.
 572 */
 573static void usb_8dev_write_bulk_callback(struct urb *urb)
 574{
 575        struct usb_8dev_tx_urb_context *context = urb->context;
 576        struct usb_8dev_priv *priv;
 577        struct net_device *netdev;
 578
 579        BUG_ON(!context);
 580
 581        priv = context->priv;
 582        netdev = priv->netdev;
 583
 584        /* free up our allocated buffer */
 585        usb_free_coherent(urb->dev, urb->transfer_buffer_length,
 586                          urb->transfer_buffer, urb->transfer_dma);
 587
 588        atomic_dec(&priv->active_tx_urbs);
 589
 590        if (!netif_device_present(netdev))
 591                return;
 592
 593        if (urb->status)
 594                netdev_info(netdev, "Tx URB aborted (%d)\n",
 595                         urb->status);
 596
 597        netdev->stats.tx_packets++;
 598        netdev->stats.tx_bytes += context->dlc;
 599
 600        can_get_echo_skb(netdev, context->echo_index);
 601
 602        can_led_event(netdev, CAN_LED_EVENT_TX);
 603
 604        /* Release context */
 605        context->echo_index = MAX_TX_URBS;
 606
 607        netif_wake_queue(netdev);
 608}
 609
 610/* Send data to device */
 611static netdev_tx_t usb_8dev_start_xmit(struct sk_buff *skb,
 612                                      struct net_device *netdev)
 613{
 614        struct usb_8dev_priv *priv = netdev_priv(netdev);
 615        struct net_device_stats *stats = &netdev->stats;
 616        struct can_frame *cf = (struct can_frame *) skb->data;
 617        struct usb_8dev_tx_msg *msg;
 618        struct urb *urb;
 619        struct usb_8dev_tx_urb_context *context = NULL;
 620        u8 *buf;
 621        int i, err;
 622        size_t size = sizeof(struct usb_8dev_tx_msg);
 623
 624        if (can_dropped_invalid_skb(netdev, skb))
 625                return NETDEV_TX_OK;
 626
 627        /* create a URB, and a buffer for it, and copy the data to the URB */
 628        urb = usb_alloc_urb(0, GFP_ATOMIC);
 629        if (!urb) {
 630                netdev_err(netdev, "No memory left for URBs\n");
 631                goto nomem;
 632        }
 633
 634        buf = usb_alloc_coherent(priv->udev, size, GFP_ATOMIC,
 635                                 &urb->transfer_dma);
 636        if (!buf) {
 637                netdev_err(netdev, "No memory left for USB buffer\n");
 638                goto nomembuf;
 639        }
 640
 641        memset(buf, 0, size);
 642
 643        msg = (struct usb_8dev_tx_msg *)buf;
 644        msg->begin = USB_8DEV_DATA_START;
 645        msg->flags = 0x00;
 646
 647        if (cf->can_id & CAN_RTR_FLAG)
 648                msg->flags |= USB_8DEV_RTR;
 649
 650        if (cf->can_id & CAN_EFF_FLAG)
 651                msg->flags |= USB_8DEV_EXTID;
 652
 653        msg->id = cpu_to_be32(cf->can_id & CAN_ERR_MASK);
 654        msg->dlc = cf->can_dlc;
 655        memcpy(msg->data, cf->data, cf->can_dlc);
 656        msg->end = USB_8DEV_DATA_END;
 657
 658        for (i = 0; i < MAX_TX_URBS; i++) {
 659                if (priv->tx_contexts[i].echo_index == MAX_TX_URBS) {
 660                        context = &priv->tx_contexts[i];
 661                        break;
 662                }
 663        }
 664
 665        /* May never happen! When this happens we'd more URBs in flight as
 666         * allowed (MAX_TX_URBS).
 667         */
 668        if (!context)
 669                goto nofreecontext;
 670
 671        context->priv = priv;
 672        context->echo_index = i;
 673        context->dlc = cf->can_dlc;
 674
 675        usb_fill_bulk_urb(urb, priv->udev,
 676                          usb_sndbulkpipe(priv->udev, USB_8DEV_ENDP_DATA_TX),
 677                          buf, size, usb_8dev_write_bulk_callback, context);
 678        urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 679        usb_anchor_urb(urb, &priv->tx_submitted);
 680
 681        can_put_echo_skb(skb, netdev, context->echo_index);
 682
 683        atomic_inc(&priv->active_tx_urbs);
 684
 685        err = usb_submit_urb(urb, GFP_ATOMIC);
 686        if (unlikely(err))
 687                goto failed;
 688        else if (atomic_read(&priv->active_tx_urbs) >= MAX_TX_URBS)
 689                /* Slow down tx path */
 690                netif_stop_queue(netdev);
 691
 692        /* Release our reference to this URB, the USB core will eventually free
 693         * it entirely.
 694         */
 695        usb_free_urb(urb);
 696
 697        return NETDEV_TX_OK;
 698
 699nofreecontext:
 700        usb_unanchor_urb(urb);
 701        usb_free_coherent(priv->udev, size, buf, urb->transfer_dma);
 702
 703        netdev_warn(netdev, "couldn't find free context");
 704
 705        return NETDEV_TX_BUSY;
 706
 707failed:
 708        can_free_echo_skb(netdev, context->echo_index);
 709
 710        usb_unanchor_urb(urb);
 711        usb_free_coherent(priv->udev, size, buf, urb->transfer_dma);
 712
 713        atomic_dec(&priv->active_tx_urbs);
 714
 715        if (err == -ENODEV)
 716                netif_device_detach(netdev);
 717        else
 718                netdev_warn(netdev, "failed tx_urb %d\n", err);
 719
 720nomembuf:
 721        usb_free_urb(urb);
 722
 723nomem:
 724        dev_kfree_skb(skb);
 725        stats->tx_dropped++;
 726
 727        return NETDEV_TX_OK;
 728}
 729
 730static int usb_8dev_get_berr_counter(const struct net_device *netdev,
 731                                     struct can_berr_counter *bec)
 732{
 733        struct usb_8dev_priv *priv = netdev_priv(netdev);
 734
 735        bec->txerr = priv->bec.txerr;
 736        bec->rxerr = priv->bec.rxerr;
 737
 738        return 0;
 739}
 740
 741/* Start USB device */
 742static int usb_8dev_start(struct usb_8dev_priv *priv)
 743{
 744        struct net_device *netdev = priv->netdev;
 745        int err, i;
 746
 747        for (i = 0; i < MAX_RX_URBS; i++) {
 748                struct urb *urb = NULL;
 749                u8 *buf;
 750
 751                /* create a URB, and a buffer for it */
 752                urb = usb_alloc_urb(0, GFP_KERNEL);
 753                if (!urb) {
 754                        netdev_err(netdev, "No memory left for URBs\n");
 755                        err = -ENOMEM;
 756                        break;
 757                }
 758
 759                buf = usb_alloc_coherent(priv->udev, RX_BUFFER_SIZE, GFP_KERNEL,
 760                                         &urb->transfer_dma);
 761                if (!buf) {
 762                        netdev_err(netdev, "No memory left for USB buffer\n");
 763                        usb_free_urb(urb);
 764                        err = -ENOMEM;
 765                        break;
 766                }
 767
 768                usb_fill_bulk_urb(urb, priv->udev,
 769                                  usb_rcvbulkpipe(priv->udev,
 770                                                  USB_8DEV_ENDP_DATA_RX),
 771                                  buf, RX_BUFFER_SIZE,
 772                                  usb_8dev_read_bulk_callback, priv);
 773                urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 774                usb_anchor_urb(urb, &priv->rx_submitted);
 775
 776                err = usb_submit_urb(urb, GFP_KERNEL);
 777                if (err) {
 778                        usb_unanchor_urb(urb);
 779                        usb_free_coherent(priv->udev, RX_BUFFER_SIZE, buf,
 780                                          urb->transfer_dma);
 781                        usb_free_urb(urb);
 782                        break;
 783                }
 784
 785                /* Drop reference, USB core will take care of freeing it */
 786                usb_free_urb(urb);
 787        }
 788
 789        /* Did we submit any URBs */
 790        if (i == 0) {
 791                netdev_warn(netdev, "couldn't setup read URBs\n");
 792                return err;
 793        }
 794
 795        /* Warn if we've couldn't transmit all the URBs */
 796        if (i < MAX_RX_URBS)
 797                netdev_warn(netdev, "rx performance may be slow\n");
 798
 799        err = usb_8dev_cmd_open(priv);
 800        if (err)
 801                goto failed;
 802
 803        priv->can.state = CAN_STATE_ERROR_ACTIVE;
 804
 805        return 0;
 806
 807failed:
 808        if (err == -ENODEV)
 809                netif_device_detach(priv->netdev);
 810
 811        netdev_warn(netdev, "couldn't submit control: %d\n", err);
 812
 813        return err;
 814}
 815
 816/* Open USB device */
 817static int usb_8dev_open(struct net_device *netdev)
 818{
 819        struct usb_8dev_priv *priv = netdev_priv(netdev);
 820        int err;
 821
 822        /* common open */
 823        err = open_candev(netdev);
 824        if (err)
 825                return err;
 826
 827        can_led_event(netdev, CAN_LED_EVENT_OPEN);
 828
 829        /* finally start device */
 830        err = usb_8dev_start(priv);
 831        if (err) {
 832                if (err == -ENODEV)
 833                        netif_device_detach(priv->netdev);
 834
 835                netdev_warn(netdev, "couldn't start device: %d\n",
 836                         err);
 837
 838                close_candev(netdev);
 839
 840                return err;
 841        }
 842
 843        netif_start_queue(netdev);
 844
 845        return 0;
 846}
 847
 848static void unlink_all_urbs(struct usb_8dev_priv *priv)
 849{
 850        int i;
 851
 852        usb_kill_anchored_urbs(&priv->rx_submitted);
 853
 854        usb_kill_anchored_urbs(&priv->tx_submitted);
 855        atomic_set(&priv->active_tx_urbs, 0);
 856
 857        for (i = 0; i < MAX_TX_URBS; i++)
 858                priv->tx_contexts[i].echo_index = MAX_TX_URBS;
 859}
 860
 861/* Close USB device */
 862static int usb_8dev_close(struct net_device *netdev)
 863{
 864        struct usb_8dev_priv *priv = netdev_priv(netdev);
 865        int err = 0;
 866
 867        /* Send CLOSE command to CAN controller */
 868        err = usb_8dev_cmd_close(priv);
 869        if (err)
 870                netdev_warn(netdev, "couldn't stop device");
 871
 872        priv->can.state = CAN_STATE_STOPPED;
 873
 874        netif_stop_queue(netdev);
 875
 876        /* Stop polling */
 877        unlink_all_urbs(priv);
 878
 879        close_candev(netdev);
 880
 881        can_led_event(netdev, CAN_LED_EVENT_STOP);
 882
 883        return err;
 884}
 885
 886static const struct net_device_ops usb_8dev_netdev_ops = {
 887        .ndo_open = usb_8dev_open,
 888        .ndo_stop = usb_8dev_close,
 889        .ndo_start_xmit = usb_8dev_start_xmit,
 890};
 891
 892static const struct can_bittiming_const usb_8dev_bittiming_const = {
 893        .name = "usb_8dev",
 894        .tseg1_min = 1,
 895        .tseg1_max = 16,
 896        .tseg2_min = 1,
 897        .tseg2_max = 8,
 898        .sjw_max = 4,
 899        .brp_min = 1,
 900        .brp_max = 1024,
 901        .brp_inc = 1,
 902};
 903
 904/* Probe USB device
 905 *
 906 * Check device and firmware.
 907 * Set supported modes and bittiming constants.
 908 * Allocate some memory.
 909 */
 910static int usb_8dev_probe(struct usb_interface *intf,
 911                         const struct usb_device_id *id)
 912{
 913        struct net_device *netdev;
 914        struct usb_8dev_priv *priv;
 915        int i, err = -ENOMEM;
 916        u32 version;
 917        char buf[18];
 918        struct usb_device *usbdev = interface_to_usbdev(intf);
 919
 920        /* product id looks strange, better we also check iProduct string */
 921        if (usb_string(usbdev, usbdev->descriptor.iProduct, buf,
 922                       sizeof(buf)) > 0 && strcmp(buf, "USB2CAN converter")) {
 923                dev_info(&usbdev->dev, "ignoring: not an USB2CAN converter\n");
 924                return -ENODEV;
 925        }
 926
 927        netdev = alloc_candev(sizeof(struct usb_8dev_priv), MAX_TX_URBS);
 928        if (!netdev) {
 929                dev_err(&intf->dev, "Couldn't alloc candev\n");
 930                return -ENOMEM;
 931        }
 932
 933        priv = netdev_priv(netdev);
 934
 935        priv->udev = usbdev;
 936        priv->netdev = netdev;
 937
 938        priv->can.state = CAN_STATE_STOPPED;
 939        priv->can.clock.freq = USB_8DEV_ABP_CLOCK;
 940        priv->can.bittiming_const = &usb_8dev_bittiming_const;
 941        priv->can.do_set_mode = usb_8dev_set_mode;
 942        priv->can.do_get_berr_counter = usb_8dev_get_berr_counter;
 943        priv->can.ctrlmode_supported = CAN_CTRLMODE_LOOPBACK |
 944                                      CAN_CTRLMODE_LISTENONLY |
 945                                      CAN_CTRLMODE_ONE_SHOT;
 946
 947        netdev->netdev_ops = &usb_8dev_netdev_ops;
 948
 949        netdev->flags |= IFF_ECHO; /* we support local echo */
 950
 951        init_usb_anchor(&priv->rx_submitted);
 952
 953        init_usb_anchor(&priv->tx_submitted);
 954        atomic_set(&priv->active_tx_urbs, 0);
 955
 956        for (i = 0; i < MAX_TX_URBS; i++)
 957                priv->tx_contexts[i].echo_index = MAX_TX_URBS;
 958
 959        priv->cmd_msg_buffer = kzalloc(sizeof(struct usb_8dev_cmd_msg),
 960                                      GFP_KERNEL);
 961        if (!priv->cmd_msg_buffer)
 962                goto cleanup_candev;
 963
 964        usb_set_intfdata(intf, priv);
 965
 966        SET_NETDEV_DEV(netdev, &intf->dev);
 967
 968        mutex_init(&priv->usb_8dev_cmd_lock);
 969
 970        err = register_candev(netdev);
 971        if (err) {
 972                netdev_err(netdev,
 973                        "couldn't register CAN device: %d\n", err);
 974                goto cleanup_cmd_msg_buffer;
 975        }
 976
 977        err = usb_8dev_cmd_version(priv, &version);
 978        if (err) {
 979                netdev_err(netdev, "can't get firmware version\n");
 980                goto cleanup_unregister_candev;
 981        } else {
 982                netdev_info(netdev,
 983                         "firmware: %d.%d, hardware: %d.%d\n",
 984                         (version>>24) & 0xff, (version>>16) & 0xff,
 985                         (version>>8) & 0xff, version & 0xff);
 986        }
 987
 988        devm_can_led_init(netdev);
 989
 990        return 0;
 991
 992cleanup_unregister_candev:
 993        unregister_netdev(priv->netdev);
 994
 995cleanup_cmd_msg_buffer:
 996        kfree(priv->cmd_msg_buffer);
 997
 998cleanup_candev:
 999        free_candev(netdev);
1000
1001        return err;
1002
1003}
1004
1005/* Called by the usb core when driver is unloaded or device is removed */
1006static void usb_8dev_disconnect(struct usb_interface *intf)
1007{
1008        struct usb_8dev_priv *priv = usb_get_intfdata(intf);
1009
1010        usb_set_intfdata(intf, NULL);
1011
1012        if (priv) {
1013                netdev_info(priv->netdev, "device disconnected\n");
1014
1015                unregister_netdev(priv->netdev);
1016                free_candev(priv->netdev);
1017
1018                unlink_all_urbs(priv);
1019        }
1020
1021}
1022
1023static struct usb_driver usb_8dev_driver = {
1024        .name =         "usb_8dev",
1025        .probe =        usb_8dev_probe,
1026        .disconnect =   usb_8dev_disconnect,
1027        .id_table =     usb_8dev_table,
1028};
1029
1030module_usb_driver(usb_8dev_driver);
1031
1032MODULE_AUTHOR("Bernd Krumboeck <krumboeck@universalnet.at>");
1033MODULE_DESCRIPTION("CAN driver for 8 devices USB2CAN interfaces");
1034MODULE_LICENSE("GPL v2");
1035
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