linux/drivers/net/can/usb/mcba_usb.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/* SocketCAN driver for Microchip CAN BUS Analyzer Tool
   3 *
   4 * Copyright (C) 2017 Mobica Limited
   5 *
   6 * This driver is inspired by the 4.6.2 version of net/can/usb/usb_8dev.c
   7 */
   8
   9#include <asm/unaligned.h>
  10#include <linux/can.h>
  11#include <linux/can/dev.h>
  12#include <linux/can/error.h>
  13#include <linux/can/led.h>
  14#include <linux/module.h>
  15#include <linux/netdevice.h>
  16#include <linux/signal.h>
  17#include <linux/slab.h>
  18#include <linux/usb.h>
  19
  20/* vendor and product id */
  21#define MCBA_MODULE_NAME "mcba_usb"
  22#define MCBA_VENDOR_ID 0x04d8
  23#define MCBA_PRODUCT_ID 0x0a30
  24
  25/* driver constants */
  26#define MCBA_MAX_RX_URBS 20
  27#define MCBA_MAX_TX_URBS 20
  28#define MCBA_CTX_FREE MCBA_MAX_TX_URBS
  29
  30/* RX buffer must be bigger than msg size since at the
  31 * beggining USB messages are stacked.
  32 */
  33#define MCBA_USB_RX_BUFF_SIZE 64
  34#define MCBA_USB_TX_BUFF_SIZE (sizeof(struct mcba_usb_msg))
  35
  36/* MCBA endpoint numbers */
  37#define MCBA_USB_EP_IN 1
  38#define MCBA_USB_EP_OUT 1
  39
  40/* Microchip command id */
  41#define MBCA_CMD_RECEIVE_MESSAGE 0xE3
  42#define MBCA_CMD_I_AM_ALIVE_FROM_CAN 0xF5
  43#define MBCA_CMD_I_AM_ALIVE_FROM_USB 0xF7
  44#define MBCA_CMD_CHANGE_BIT_RATE 0xA1
  45#define MBCA_CMD_TRANSMIT_MESSAGE_EV 0xA3
  46#define MBCA_CMD_SETUP_TERMINATION_RESISTANCE 0xA8
  47#define MBCA_CMD_READ_FW_VERSION 0xA9
  48#define MBCA_CMD_NOTHING_TO_SEND 0xFF
  49#define MBCA_CMD_TRANSMIT_MESSAGE_RSP 0xE2
  50
  51#define MCBA_VER_REQ_USB 1
  52#define MCBA_VER_REQ_CAN 2
  53
  54#define MCBA_SIDL_EXID_MASK 0x8
  55#define MCBA_DLC_MASK 0xf
  56#define MCBA_DLC_RTR_MASK 0x40
  57
  58#define MCBA_CAN_STATE_WRN_TH 95
  59#define MCBA_CAN_STATE_ERR_PSV_TH 127
  60
  61#define MCBA_TERMINATION_DISABLED CAN_TERMINATION_DISABLED
  62#define MCBA_TERMINATION_ENABLED 120
  63
  64struct mcba_usb_ctx {
  65        struct mcba_priv *priv;
  66        u32 ndx;
  67        u8 dlc;
  68        bool can;
  69};
  70
  71/* Structure to hold all of our device specific stuff */
  72struct mcba_priv {
  73        struct can_priv can; /* must be the first member */
  74        struct sk_buff *echo_skb[MCBA_MAX_TX_URBS];
  75        struct mcba_usb_ctx tx_context[MCBA_MAX_TX_URBS];
  76        struct usb_device *udev;
  77        struct net_device *netdev;
  78        struct usb_anchor tx_submitted;
  79        struct usb_anchor rx_submitted;
  80        struct can_berr_counter bec;
  81        bool usb_ka_first_pass;
  82        bool can_ka_first_pass;
  83        bool can_speed_check;
  84        atomic_t free_ctx_cnt;
  85};
  86
  87/* CAN frame */
  88struct __packed mcba_usb_msg_can {
  89        u8 cmd_id;
  90        __be16 eid;
  91        __be16 sid;
  92        u8 dlc;
  93        u8 data[8];
  94        u8 timestamp[4];
  95        u8 checksum;
  96};
  97
  98/* command frame */
  99struct __packed mcba_usb_msg {
 100        u8 cmd_id;
 101        u8 unused[18];
 102};
 103
 104struct __packed mcba_usb_msg_ka_usb {
 105        u8 cmd_id;
 106        u8 termination_state;
 107        u8 soft_ver_major;
 108        u8 soft_ver_minor;
 109        u8 unused[15];
 110};
 111
 112struct __packed mcba_usb_msg_ka_can {
 113        u8 cmd_id;
 114        u8 tx_err_cnt;
 115        u8 rx_err_cnt;
 116        u8 rx_buff_ovfl;
 117        u8 tx_bus_off;
 118        __be16 can_bitrate;
 119        __le16 rx_lost;
 120        u8 can_stat;
 121        u8 soft_ver_major;
 122        u8 soft_ver_minor;
 123        u8 debug_mode;
 124        u8 test_complete;
 125        u8 test_result;
 126        u8 unused[4];
 127};
 128
 129struct __packed mcba_usb_msg_change_bitrate {
 130        u8 cmd_id;
 131        __be16 bitrate;
 132        u8 unused[16];
 133};
 134
 135struct __packed mcba_usb_msg_termination {
 136        u8 cmd_id;
 137        u8 termination;
 138        u8 unused[17];
 139};
 140
 141struct __packed mcba_usb_msg_fw_ver {
 142        u8 cmd_id;
 143        u8 pic;
 144        u8 unused[17];
 145};
 146
 147static const struct usb_device_id mcba_usb_table[] = {
 148        { USB_DEVICE(MCBA_VENDOR_ID, MCBA_PRODUCT_ID) },
 149        {} /* Terminating entry */
 150};
 151
 152MODULE_DEVICE_TABLE(usb, mcba_usb_table);
 153
 154static const u16 mcba_termination[] = { MCBA_TERMINATION_DISABLED,
 155                                        MCBA_TERMINATION_ENABLED };
 156
 157static const u32 mcba_bitrate[] = { 20000,  33333,  50000,  80000,  83333,
 158                                    100000, 125000, 150000, 175000, 200000,
 159                                    225000, 250000, 275000, 300000, 500000,
 160                                    625000, 800000, 1000000 };
 161
 162static inline void mcba_init_ctx(struct mcba_priv *priv)
 163{
 164        int i = 0;
 165
 166        for (i = 0; i < MCBA_MAX_TX_URBS; i++) {
 167                priv->tx_context[i].ndx = MCBA_CTX_FREE;
 168                priv->tx_context[i].priv = priv;
 169        }
 170
 171        atomic_set(&priv->free_ctx_cnt, ARRAY_SIZE(priv->tx_context));
 172}
 173
 174static inline struct mcba_usb_ctx *mcba_usb_get_free_ctx(struct mcba_priv *priv,
 175                                                         struct can_frame *cf)
 176{
 177        int i = 0;
 178        struct mcba_usb_ctx *ctx = NULL;
 179
 180        for (i = 0; i < MCBA_MAX_TX_URBS; i++) {
 181                if (priv->tx_context[i].ndx == MCBA_CTX_FREE) {
 182                        ctx = &priv->tx_context[i];
 183                        ctx->ndx = i;
 184
 185                        if (cf) {
 186                                ctx->can = true;
 187                                ctx->dlc = cf->can_dlc;
 188                        } else {
 189                                ctx->can = false;
 190                                ctx->dlc = 0;
 191                        }
 192
 193                        atomic_dec(&priv->free_ctx_cnt);
 194                        break;
 195                }
 196        }
 197
 198        if (!atomic_read(&priv->free_ctx_cnt))
 199                /* That was the last free ctx. Slow down tx path */
 200                netif_stop_queue(priv->netdev);
 201
 202        return ctx;
 203}
 204
 205/* mcba_usb_free_ctx and mcba_usb_get_free_ctx are executed by different
 206 * threads. The order of execution in below function is important.
 207 */
 208static inline void mcba_usb_free_ctx(struct mcba_usb_ctx *ctx)
 209{
 210        /* Increase number of free ctxs before freeing ctx */
 211        atomic_inc(&ctx->priv->free_ctx_cnt);
 212
 213        ctx->ndx = MCBA_CTX_FREE;
 214
 215        /* Wake up the queue once ctx is marked free */
 216        netif_wake_queue(ctx->priv->netdev);
 217}
 218
 219static void mcba_usb_write_bulk_callback(struct urb *urb)
 220{
 221        struct mcba_usb_ctx *ctx = urb->context;
 222        struct net_device *netdev;
 223
 224        WARN_ON(!ctx);
 225
 226        netdev = ctx->priv->netdev;
 227
 228        /* free up our allocated buffer */
 229        usb_free_coherent(urb->dev, urb->transfer_buffer_length,
 230                          urb->transfer_buffer, urb->transfer_dma);
 231
 232        if (ctx->can) {
 233                if (!netif_device_present(netdev))
 234                        return;
 235
 236                netdev->stats.tx_packets++;
 237                netdev->stats.tx_bytes += ctx->dlc;
 238
 239                can_led_event(netdev, CAN_LED_EVENT_TX);
 240                can_get_echo_skb(netdev, ctx->ndx);
 241        }
 242
 243        if (urb->status)
 244                netdev_info(netdev, "Tx URB aborted (%d)\n", urb->status);
 245
 246        /* Release the context */
 247        mcba_usb_free_ctx(ctx);
 248}
 249
 250/* Send data to device */
 251static netdev_tx_t mcba_usb_xmit(struct mcba_priv *priv,
 252                                 struct mcba_usb_msg *usb_msg,
 253                                 struct mcba_usb_ctx *ctx)
 254{
 255        struct urb *urb;
 256        u8 *buf;
 257        int err;
 258
 259        /* create a URB, and a buffer for it, and copy the data to the URB */
 260        urb = usb_alloc_urb(0, GFP_ATOMIC);
 261        if (!urb)
 262                return -ENOMEM;
 263
 264        buf = usb_alloc_coherent(priv->udev, MCBA_USB_TX_BUFF_SIZE, GFP_ATOMIC,
 265                                 &urb->transfer_dma);
 266        if (!buf) {
 267                err = -ENOMEM;
 268                goto nomembuf;
 269        }
 270
 271        memcpy(buf, usb_msg, MCBA_USB_TX_BUFF_SIZE);
 272
 273        usb_fill_bulk_urb(urb, priv->udev,
 274                          usb_sndbulkpipe(priv->udev, MCBA_USB_EP_OUT), buf,
 275                          MCBA_USB_TX_BUFF_SIZE, mcba_usb_write_bulk_callback,
 276                          ctx);
 277
 278        urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 279        usb_anchor_urb(urb, &priv->tx_submitted);
 280
 281        err = usb_submit_urb(urb, GFP_ATOMIC);
 282        if (unlikely(err))
 283                goto failed;
 284
 285        /* Release our reference to this URB, the USB core will eventually free
 286         * it entirely.
 287         */
 288        usb_free_urb(urb);
 289
 290        return 0;
 291
 292failed:
 293        usb_unanchor_urb(urb);
 294        usb_free_coherent(priv->udev, MCBA_USB_TX_BUFF_SIZE, buf,
 295                          urb->transfer_dma);
 296
 297        if (err == -ENODEV)
 298                netif_device_detach(priv->netdev);
 299        else
 300                netdev_warn(priv->netdev, "failed tx_urb %d\n", err);
 301
 302nomembuf:
 303        usb_free_urb(urb);
 304
 305        return err;
 306}
 307
 308/* Send data to device */
 309static netdev_tx_t mcba_usb_start_xmit(struct sk_buff *skb,
 310                                       struct net_device *netdev)
 311{
 312        struct mcba_priv *priv = netdev_priv(netdev);
 313        struct can_frame *cf = (struct can_frame *)skb->data;
 314        struct mcba_usb_ctx *ctx = NULL;
 315        struct net_device_stats *stats = &priv->netdev->stats;
 316        u16 sid;
 317        int err;
 318        struct mcba_usb_msg_can usb_msg = {
 319                .cmd_id = MBCA_CMD_TRANSMIT_MESSAGE_EV
 320        };
 321
 322        if (can_dropped_invalid_skb(netdev, skb))
 323                return NETDEV_TX_OK;
 324
 325        ctx = mcba_usb_get_free_ctx(priv, cf);
 326        if (!ctx)
 327                return NETDEV_TX_BUSY;
 328
 329        can_put_echo_skb(skb, priv->netdev, ctx->ndx);
 330
 331        if (cf->can_id & CAN_EFF_FLAG) {
 332                /* SIDH    | SIDL                 | EIDH   | EIDL
 333                 * 28 - 21 | 20 19 18 x x x 17 16 | 15 - 8 | 7 - 0
 334                 */
 335                sid = MCBA_SIDL_EXID_MASK;
 336                /* store 28-18 bits */
 337                sid |= (cf->can_id & 0x1ffc0000) >> 13;
 338                /* store 17-16 bits */
 339                sid |= (cf->can_id & 0x30000) >> 16;
 340                put_unaligned_be16(sid, &usb_msg.sid);
 341
 342                /* store 15-0 bits */
 343                put_unaligned_be16(cf->can_id & 0xffff, &usb_msg.eid);
 344        } else {
 345                /* SIDH   | SIDL
 346                 * 10 - 3 | 2 1 0 x x x x x
 347                 */
 348                put_unaligned_be16((cf->can_id & CAN_SFF_MASK) << 5,
 349                                   &usb_msg.sid);
 350                usb_msg.eid = 0;
 351        }
 352
 353        usb_msg.dlc = cf->can_dlc;
 354
 355        memcpy(usb_msg.data, cf->data, usb_msg.dlc);
 356
 357        if (cf->can_id & CAN_RTR_FLAG)
 358                usb_msg.dlc |= MCBA_DLC_RTR_MASK;
 359
 360        err = mcba_usb_xmit(priv, (struct mcba_usb_msg *)&usb_msg, ctx);
 361        if (err)
 362                goto xmit_failed;
 363
 364        return NETDEV_TX_OK;
 365
 366xmit_failed:
 367        can_free_echo_skb(priv->netdev, ctx->ndx);
 368        mcba_usb_free_ctx(ctx);
 369        dev_kfree_skb(skb);
 370        stats->tx_dropped++;
 371
 372        return NETDEV_TX_OK;
 373}
 374
 375/* Send cmd to device */
 376static void mcba_usb_xmit_cmd(struct mcba_priv *priv,
 377                              struct mcba_usb_msg *usb_msg)
 378{
 379        struct mcba_usb_ctx *ctx = NULL;
 380        int err;
 381
 382        ctx = mcba_usb_get_free_ctx(priv, NULL);
 383        if (!ctx) {
 384                netdev_err(priv->netdev,
 385                           "Lack of free ctx. Sending (%d) cmd aborted",
 386                           usb_msg->cmd_id);
 387
 388                return;
 389        }
 390
 391        err = mcba_usb_xmit(priv, usb_msg, ctx);
 392        if (err)
 393                netdev_err(priv->netdev, "Failed to send cmd (%d)",
 394                           usb_msg->cmd_id);
 395}
 396
 397static void mcba_usb_xmit_change_bitrate(struct mcba_priv *priv, u16 bitrate)
 398{
 399        struct mcba_usb_msg_change_bitrate usb_msg = {
 400                .cmd_id = MBCA_CMD_CHANGE_BIT_RATE
 401        };
 402
 403        put_unaligned_be16(bitrate, &usb_msg.bitrate);
 404
 405        mcba_usb_xmit_cmd(priv, (struct mcba_usb_msg *)&usb_msg);
 406}
 407
 408static void mcba_usb_xmit_read_fw_ver(struct mcba_priv *priv, u8 pic)
 409{
 410        struct mcba_usb_msg_fw_ver usb_msg = {
 411                .cmd_id = MBCA_CMD_READ_FW_VERSION,
 412                .pic = pic
 413        };
 414
 415        mcba_usb_xmit_cmd(priv, (struct mcba_usb_msg *)&usb_msg);
 416}
 417
 418static void mcba_usb_process_can(struct mcba_priv *priv,
 419                                 struct mcba_usb_msg_can *msg)
 420{
 421        struct can_frame *cf;
 422        struct sk_buff *skb;
 423        struct net_device_stats *stats = &priv->netdev->stats;
 424        u16 sid;
 425
 426        skb = alloc_can_skb(priv->netdev, &cf);
 427        if (!skb)
 428                return;
 429
 430        sid = get_unaligned_be16(&msg->sid);
 431
 432        if (sid & MCBA_SIDL_EXID_MASK) {
 433                /* SIDH    | SIDL                 | EIDH   | EIDL
 434                 * 28 - 21 | 20 19 18 x x x 17 16 | 15 - 8 | 7 - 0
 435                 */
 436                cf->can_id = CAN_EFF_FLAG;
 437
 438                /* store 28-18 bits */
 439                cf->can_id |= (sid & 0xffe0) << 13;
 440                /* store 17-16 bits */
 441                cf->can_id |= (sid & 3) << 16;
 442                /* store 15-0 bits */
 443                cf->can_id |= get_unaligned_be16(&msg->eid);
 444        } else {
 445                /* SIDH   | SIDL
 446                 * 10 - 3 | 2 1 0 x x x x x
 447                 */
 448                cf->can_id = (sid & 0xffe0) >> 5;
 449        }
 450
 451        if (msg->dlc & MCBA_DLC_RTR_MASK)
 452                cf->can_id |= CAN_RTR_FLAG;
 453
 454        cf->can_dlc = get_can_dlc(msg->dlc & MCBA_DLC_MASK);
 455
 456        memcpy(cf->data, msg->data, cf->can_dlc);
 457
 458        stats->rx_packets++;
 459        stats->rx_bytes += cf->can_dlc;
 460
 461        can_led_event(priv->netdev, CAN_LED_EVENT_RX);
 462        netif_rx(skb);
 463}
 464
 465static void mcba_usb_process_ka_usb(struct mcba_priv *priv,
 466                                    struct mcba_usb_msg_ka_usb *msg)
 467{
 468        if (unlikely(priv->usb_ka_first_pass)) {
 469                netdev_info(priv->netdev, "PIC USB version %hhu.%hhu\n",
 470                            msg->soft_ver_major, msg->soft_ver_minor);
 471
 472                priv->usb_ka_first_pass = false;
 473        }
 474
 475        if (msg->termination_state)
 476                priv->can.termination = MCBA_TERMINATION_ENABLED;
 477        else
 478                priv->can.termination = MCBA_TERMINATION_DISABLED;
 479}
 480
 481static u32 convert_can2host_bitrate(struct mcba_usb_msg_ka_can *msg)
 482{
 483        const u32 bitrate = get_unaligned_be16(&msg->can_bitrate);
 484
 485        if ((bitrate == 33) || (bitrate == 83))
 486                return bitrate * 1000 + 333;
 487        else
 488                return bitrate * 1000;
 489}
 490
 491static void mcba_usb_process_ka_can(struct mcba_priv *priv,
 492                                    struct mcba_usb_msg_ka_can *msg)
 493{
 494        if (unlikely(priv->can_ka_first_pass)) {
 495                netdev_info(priv->netdev, "PIC CAN version %hhu.%hhu\n",
 496                            msg->soft_ver_major, msg->soft_ver_minor);
 497
 498                priv->can_ka_first_pass = false;
 499        }
 500
 501        if (unlikely(priv->can_speed_check)) {
 502                const u32 bitrate = convert_can2host_bitrate(msg);
 503
 504                priv->can_speed_check = false;
 505
 506                if (bitrate != priv->can.bittiming.bitrate)
 507                        netdev_err(
 508                            priv->netdev,
 509                            "Wrong bitrate reported by the device (%u). Expected %u",
 510                            bitrate, priv->can.bittiming.bitrate);
 511        }
 512
 513        priv->bec.txerr = msg->tx_err_cnt;
 514        priv->bec.rxerr = msg->rx_err_cnt;
 515
 516        if (msg->tx_bus_off)
 517                priv->can.state = CAN_STATE_BUS_OFF;
 518
 519        else if ((priv->bec.txerr > MCBA_CAN_STATE_ERR_PSV_TH) ||
 520                 (priv->bec.rxerr > MCBA_CAN_STATE_ERR_PSV_TH))
 521                priv->can.state = CAN_STATE_ERROR_PASSIVE;
 522
 523        else if ((priv->bec.txerr > MCBA_CAN_STATE_WRN_TH) ||
 524                 (priv->bec.rxerr > MCBA_CAN_STATE_WRN_TH))
 525                priv->can.state = CAN_STATE_ERROR_WARNING;
 526}
 527
 528static void mcba_usb_process_rx(struct mcba_priv *priv,
 529                                struct mcba_usb_msg *msg)
 530{
 531        switch (msg->cmd_id) {
 532        case MBCA_CMD_I_AM_ALIVE_FROM_CAN:
 533                mcba_usb_process_ka_can(priv,
 534                                        (struct mcba_usb_msg_ka_can *)msg);
 535                break;
 536
 537        case MBCA_CMD_I_AM_ALIVE_FROM_USB:
 538                mcba_usb_process_ka_usb(priv,
 539                                        (struct mcba_usb_msg_ka_usb *)msg);
 540                break;
 541
 542        case MBCA_CMD_RECEIVE_MESSAGE:
 543                mcba_usb_process_can(priv, (struct mcba_usb_msg_can *)msg);
 544                break;
 545
 546        case MBCA_CMD_NOTHING_TO_SEND:
 547                /* Side effect of communication between PIC_USB and PIC_CAN.
 548                 * PIC_CAN is telling us that it has nothing to send
 549                 */
 550                break;
 551
 552        case MBCA_CMD_TRANSMIT_MESSAGE_RSP:
 553                /* Transmission response from the device containing timestamp */
 554                break;
 555
 556        default:
 557                netdev_warn(priv->netdev, "Unsupported msg (0x%hhX)",
 558                            msg->cmd_id);
 559                break;
 560        }
 561}
 562
 563/* Callback for reading data from device
 564 *
 565 * Check urb status, call read function and resubmit urb read operation.
 566 */
 567static void mcba_usb_read_bulk_callback(struct urb *urb)
 568{
 569        struct mcba_priv *priv = urb->context;
 570        struct net_device *netdev;
 571        int retval;
 572        int pos = 0;
 573
 574        netdev = priv->netdev;
 575
 576        if (!netif_device_present(netdev))
 577                return;
 578
 579        switch (urb->status) {
 580        case 0: /* success */
 581                break;
 582
 583        case -ENOENT:
 584        case -EPIPE:
 585        case -EPROTO:
 586        case -ESHUTDOWN:
 587                return;
 588
 589        default:
 590                netdev_info(netdev, "Rx URB aborted (%d)\n", urb->status);
 591
 592                goto resubmit_urb;
 593        }
 594
 595        while (pos < urb->actual_length) {
 596                struct mcba_usb_msg *msg;
 597
 598                if (pos + sizeof(struct mcba_usb_msg) > urb->actual_length) {
 599                        netdev_err(priv->netdev, "format error\n");
 600                        break;
 601                }
 602
 603                msg = (struct mcba_usb_msg *)(urb->transfer_buffer + pos);
 604                mcba_usb_process_rx(priv, msg);
 605
 606                pos += sizeof(struct mcba_usb_msg);
 607        }
 608
 609resubmit_urb:
 610
 611        usb_fill_bulk_urb(urb, priv->udev,
 612                          usb_rcvbulkpipe(priv->udev, MCBA_USB_EP_OUT),
 613                          urb->transfer_buffer, MCBA_USB_RX_BUFF_SIZE,
 614                          mcba_usb_read_bulk_callback, priv);
 615
 616        retval = usb_submit_urb(urb, GFP_ATOMIC);
 617
 618        if (retval == -ENODEV)
 619                netif_device_detach(netdev);
 620        else if (retval)
 621                netdev_err(netdev, "failed resubmitting read bulk urb: %d\n",
 622                           retval);
 623}
 624
 625/* Start USB device */
 626static int mcba_usb_start(struct mcba_priv *priv)
 627{
 628        struct net_device *netdev = priv->netdev;
 629        int err, i;
 630
 631        mcba_init_ctx(priv);
 632
 633        for (i = 0; i < MCBA_MAX_RX_URBS; i++) {
 634                struct urb *urb = NULL;
 635                u8 *buf;
 636
 637                /* create a URB, and a buffer for it */
 638                urb = usb_alloc_urb(0, GFP_KERNEL);
 639                if (!urb) {
 640                        err = -ENOMEM;
 641                        break;
 642                }
 643
 644                buf = usb_alloc_coherent(priv->udev, MCBA_USB_RX_BUFF_SIZE,
 645                                         GFP_KERNEL, &urb->transfer_dma);
 646                if (!buf) {
 647                        netdev_err(netdev, "No memory left for USB buffer\n");
 648                        usb_free_urb(urb);
 649                        err = -ENOMEM;
 650                        break;
 651                }
 652
 653                usb_fill_bulk_urb(urb, priv->udev,
 654                                  usb_rcvbulkpipe(priv->udev, MCBA_USB_EP_IN),
 655                                  buf, MCBA_USB_RX_BUFF_SIZE,
 656                                  mcba_usb_read_bulk_callback, priv);
 657                urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 658                usb_anchor_urb(urb, &priv->rx_submitted);
 659
 660                err = usb_submit_urb(urb, GFP_KERNEL);
 661                if (err) {
 662                        usb_unanchor_urb(urb);
 663                        usb_free_coherent(priv->udev, MCBA_USB_RX_BUFF_SIZE,
 664                                          buf, urb->transfer_dma);
 665                        usb_free_urb(urb);
 666                        break;
 667                }
 668
 669                /* Drop reference, USB core will take care of freeing it */
 670                usb_free_urb(urb);
 671        }
 672
 673        /* Did we submit any URBs */
 674        if (i == 0) {
 675                netdev_warn(netdev, "couldn't setup read URBs\n");
 676                return err;
 677        }
 678
 679        /* Warn if we've couldn't transmit all the URBs */
 680        if (i < MCBA_MAX_RX_URBS)
 681                netdev_warn(netdev, "rx performance may be slow\n");
 682
 683        mcba_usb_xmit_read_fw_ver(priv, MCBA_VER_REQ_USB);
 684        mcba_usb_xmit_read_fw_ver(priv, MCBA_VER_REQ_CAN);
 685
 686        return err;
 687}
 688
 689/* Open USB device */
 690static int mcba_usb_open(struct net_device *netdev)
 691{
 692        struct mcba_priv *priv = netdev_priv(netdev);
 693        int err;
 694
 695        /* common open */
 696        err = open_candev(netdev);
 697        if (err)
 698                return err;
 699
 700        priv->can_speed_check = true;
 701        priv->can.state = CAN_STATE_ERROR_ACTIVE;
 702
 703        can_led_event(netdev, CAN_LED_EVENT_OPEN);
 704        netif_start_queue(netdev);
 705
 706        return 0;
 707}
 708
 709static void mcba_urb_unlink(struct mcba_priv *priv)
 710{
 711        usb_kill_anchored_urbs(&priv->rx_submitted);
 712        usb_kill_anchored_urbs(&priv->tx_submitted);
 713}
 714
 715/* Close USB device */
 716static int mcba_usb_close(struct net_device *netdev)
 717{
 718        struct mcba_priv *priv = netdev_priv(netdev);
 719
 720        priv->can.state = CAN_STATE_STOPPED;
 721
 722        netif_stop_queue(netdev);
 723
 724        /* Stop polling */
 725        mcba_urb_unlink(priv);
 726
 727        close_candev(netdev);
 728        can_led_event(netdev, CAN_LED_EVENT_STOP);
 729
 730        return 0;
 731}
 732
 733/* Set network device mode
 734 *
 735 * Maybe we should leave this function empty, because the device
 736 * set mode variable with open command.
 737 */
 738static int mcba_net_set_mode(struct net_device *netdev, enum can_mode mode)
 739{
 740        return 0;
 741}
 742
 743static int mcba_net_get_berr_counter(const struct net_device *netdev,
 744                                     struct can_berr_counter *bec)
 745{
 746        struct mcba_priv *priv = netdev_priv(netdev);
 747
 748        bec->txerr = priv->bec.txerr;
 749        bec->rxerr = priv->bec.rxerr;
 750
 751        return 0;
 752}
 753
 754static const struct net_device_ops mcba_netdev_ops = {
 755        .ndo_open = mcba_usb_open,
 756        .ndo_stop = mcba_usb_close,
 757        .ndo_start_xmit = mcba_usb_start_xmit,
 758};
 759
 760/* Microchip CANBUS has hardcoded bittiming values by default.
 761 * This function sends request via USB to change the speed and align bittiming
 762 * values for presentation purposes only
 763 */
 764static int mcba_net_set_bittiming(struct net_device *netdev)
 765{
 766        struct mcba_priv *priv = netdev_priv(netdev);
 767        const u16 bitrate_kbps = priv->can.bittiming.bitrate / 1000;
 768
 769        mcba_usb_xmit_change_bitrate(priv, bitrate_kbps);
 770
 771        return 0;
 772}
 773
 774static int mcba_set_termination(struct net_device *netdev, u16 term)
 775{
 776        struct mcba_priv *priv = netdev_priv(netdev);
 777        struct mcba_usb_msg_termination usb_msg = {
 778                .cmd_id = MBCA_CMD_SETUP_TERMINATION_RESISTANCE
 779        };
 780
 781        if (term == MCBA_TERMINATION_ENABLED)
 782                usb_msg.termination = 1;
 783        else
 784                usb_msg.termination = 0;
 785
 786        mcba_usb_xmit_cmd(priv, (struct mcba_usb_msg *)&usb_msg);
 787
 788        return 0;
 789}
 790
 791static int mcba_usb_probe(struct usb_interface *intf,
 792                          const struct usb_device_id *id)
 793{
 794        struct net_device *netdev;
 795        struct mcba_priv *priv;
 796        int err = -ENOMEM;
 797        struct usb_device *usbdev = interface_to_usbdev(intf);
 798
 799        netdev = alloc_candev(sizeof(struct mcba_priv), MCBA_MAX_TX_URBS);
 800        if (!netdev) {
 801                dev_err(&intf->dev, "Couldn't alloc candev\n");
 802                return -ENOMEM;
 803        }
 804
 805        priv = netdev_priv(netdev);
 806
 807        priv->udev = usbdev;
 808        priv->netdev = netdev;
 809        priv->usb_ka_first_pass = true;
 810        priv->can_ka_first_pass = true;
 811        priv->can_speed_check = false;
 812
 813        init_usb_anchor(&priv->rx_submitted);
 814        init_usb_anchor(&priv->tx_submitted);
 815
 816        usb_set_intfdata(intf, priv);
 817
 818        /* Init CAN device */
 819        priv->can.state = CAN_STATE_STOPPED;
 820        priv->can.termination_const = mcba_termination;
 821        priv->can.termination_const_cnt = ARRAY_SIZE(mcba_termination);
 822        priv->can.bitrate_const = mcba_bitrate;
 823        priv->can.bitrate_const_cnt = ARRAY_SIZE(mcba_bitrate);
 824
 825        priv->can.do_set_termination = mcba_set_termination;
 826        priv->can.do_set_mode = mcba_net_set_mode;
 827        priv->can.do_get_berr_counter = mcba_net_get_berr_counter;
 828        priv->can.do_set_bittiming = mcba_net_set_bittiming;
 829
 830        netdev->netdev_ops = &mcba_netdev_ops;
 831
 832        netdev->flags |= IFF_ECHO; /* we support local echo */
 833
 834        SET_NETDEV_DEV(netdev, &intf->dev);
 835
 836        err = register_candev(netdev);
 837        if (err) {
 838                netdev_err(netdev, "couldn't register CAN device: %d\n", err);
 839
 840                goto cleanup_free_candev;
 841        }
 842
 843        devm_can_led_init(netdev);
 844
 845        /* Start USB dev only if we have successfully registered CAN device */
 846        err = mcba_usb_start(priv);
 847        if (err) {
 848                if (err == -ENODEV)
 849                        netif_device_detach(priv->netdev);
 850
 851                netdev_warn(netdev, "couldn't start device: %d\n", err);
 852
 853                goto cleanup_unregister_candev;
 854        }
 855
 856        dev_info(&intf->dev, "Microchip CAN BUS Analyzer connected\n");
 857
 858        return 0;
 859
 860cleanup_unregister_candev:
 861        unregister_candev(priv->netdev);
 862
 863cleanup_free_candev:
 864        free_candev(netdev);
 865
 866        return err;
 867}
 868
 869/* Called by the usb core when driver is unloaded or device is removed */
 870static void mcba_usb_disconnect(struct usb_interface *intf)
 871{
 872        struct mcba_priv *priv = usb_get_intfdata(intf);
 873
 874        usb_set_intfdata(intf, NULL);
 875
 876        netdev_info(priv->netdev, "device disconnected\n");
 877
 878        unregister_candev(priv->netdev);
 879        free_candev(priv->netdev);
 880
 881        mcba_urb_unlink(priv);
 882}
 883
 884static struct usb_driver mcba_usb_driver = {
 885        .name = MCBA_MODULE_NAME,
 886        .probe = mcba_usb_probe,
 887        .disconnect = mcba_usb_disconnect,
 888        .id_table = mcba_usb_table,
 889};
 890
 891module_usb_driver(mcba_usb_driver);
 892
 893MODULE_AUTHOR("Remigiusz Kołłątaj <remigiusz.kollataj@mobica.com>");
 894MODULE_DESCRIPTION("SocketCAN driver for Microchip CAN BUS Analyzer Tool");
 895MODULE_LICENSE("GPL v2");
 896