drivers/net/can/usb/mcba_usb.c

   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  * beginning 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 /* Microchip command id */
  37 #define MBCA_CMD_RECEIVE_MESSAGE 0xE3
  38 #define MBCA_CMD_I_AM_ALIVE_FROM_CAN 0xF5
  39 #define MBCA_CMD_I_AM_ALIVE_FROM_USB 0xF7
  40 #define MBCA_CMD_CHANGE_BIT_RATE 0xA1
  41 #define MBCA_CMD_TRANSMIT_MESSAGE_EV 0xA3
  42 #define MBCA_CMD_SETUP_TERMINATION_RESISTANCE 0xA8
  43 #define MBCA_CMD_READ_FW_VERSION 0xA9
  44 #define MBCA_CMD_NOTHING_TO_SEND 0xFF
  45 #define MBCA_CMD_TRANSMIT_MESSAGE_RSP 0xE2
  46
  47 #define MCBA_VER_REQ_USB 1
  48 #define MCBA_VER_REQ_CAN 2
  49
  50 #define MCBA_SIDL_EXID_MASK 0x8
  51 #define MCBA_DLC_MASK 0xf
  52 #define MCBA_DLC_RTR_MASK 0x40
  53
  54 #define MCBA_CAN_STATE_WRN_TH 95
  55 #define MCBA_CAN_STATE_ERR_PSV_TH 127
  56
  57 #define MCBA_TERMINATION_DISABLED CAN_TERMINATION_DISABLED
  58 #define MCBA_TERMINATION_ENABLED 120
  59
  60 struct mcba_usb_ctx {
  61         struct mcba_priv *priv;
  62         u32 ndx;
  63         u8 dlc;
  64         bool can;
  65 };
  66
  67 /* Structure to hold all of our device specific stuff */
  68 struct mcba_priv {
  69         struct can_priv can; /* must be the first member */
  70         struct sk_buff *echo_skb[MCBA_MAX_TX_URBS];
  71         struct mcba_usb_ctx tx_context[MCBA_MAX_TX_URBS];
  72         struct usb_device *udev;
  73         struct net_device *netdev;
  74         struct usb_anchor tx_submitted;
  75         struct usb_anchor rx_submitted;
  76         struct can_berr_counter bec;
  77         bool usb_ka_first_pass;
  78         bool can_ka_first_pass;
  79         bool can_speed_check;
  80         atomic_t free_ctx_cnt;
  81         void *rxbuf[MCBA_MAX_RX_URBS];
  82         dma_addr_t rxbuf_dma[MCBA_MAX_RX_URBS];
  83         int rx_pipe;
  84         int tx_pipe;
  85 };
  86
  87 /* CAN frame */
  88 struct __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 */
  99 struct __packed mcba_usb_msg {
 100         u8 cmd_id;
 101         u8 unused[18];
 102 };
 103
 104 struct __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
 112 struct __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
 129 struct __packed mcba_usb_msg_change_bitrate {
 130         u8 cmd_id;
 131         __be16 bitrate;
 132         u8 unused[16];
 133 };
 134
 135 struct __packed mcba_usb_msg_termination {
 136         u8 cmd_id;
 137         u8 termination;
 138         u8 unused[17];
 139 };
 140
 141 struct __packed mcba_usb_msg_fw_ver {
 142         u8 cmd_id;
 143         u8 pic;
 144         u8 unused[17];
 145 };
 146
 147 static const struct usb_device_id mcba_usb_table[] = {
 148         { USB_DEVICE(MCBA_VENDOR_ID, MCBA_PRODUCT_ID) },
 149         {} /* Terminating entry */
 150 };
 151
 152 MODULE_DEVICE_TABLE(usb, mcba_usb_table);
 153
 154 static const u16 mcba_termination[] = { MCBA_TERMINATION_DISABLED,
 155                                         MCBA_TERMINATION_ENABLED };
 156
 157 static 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
 162 static 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
 174 static 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  */
 208 static 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
 219 static 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 */
 251 static 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, priv->tx_pipe, buf, MCBA_USB_TX_BUFF_SIZE,
 274                           mcba_usb_write_bulk_callback, ctx);
 275
 276         urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 277         usb_anchor_urb(urb, &priv->tx_submitted);
 278
 279         err = usb_submit_urb(urb, GFP_ATOMIC);
 280         if (unlikely(err))
 281                 goto failed;
 282
 283         /* Release our reference to this URB, the USB core will eventually free
 284          * it entirely.
 285          */
 286         usb_free_urb(urb);
 287
 288         return 0;
 289
 290 failed:
 291         usb_unanchor_urb(urb);
 292         usb_free_coherent(priv->udev, MCBA_USB_TX_BUFF_SIZE, buf,
 293                           urb->transfer_dma);
 294
 295         if (err == -ENODEV)
 296                 netif_device_detach(priv->netdev);
 297         else
 298                 netdev_warn(priv->netdev, "failed tx_urb %d\n", err);
 299
 300 nomembuf:
 301         usb_free_urb(urb);
 302
 303         return err;
 304 }
 305
 306 /* Send data to device */
 307 static netdev_tx_t mcba_usb_start_xmit(struct sk_buff *skb,
 308                                        struct net_device *netdev)
 309 {
 310         struct mcba_priv *priv = netdev_priv(netdev);
 311         struct can_frame *cf = (struct can_frame *)skb->data;
 312         struct mcba_usb_ctx *ctx = NULL;
 313         struct net_device_stats *stats = &priv->netdev->stats;
 314         u16 sid;
 315         int err;
 316         struct mcba_usb_msg_can usb_msg = {
 317                 .cmd_id = MBCA_CMD_TRANSMIT_MESSAGE_EV
 318         };
 319
 320         if (can_dropped_invalid_skb(netdev, skb))
 321                 return NETDEV_TX_OK;
 322
 323         ctx = mcba_usb_get_free_ctx(priv, cf);
 324         if (!ctx)
 325                 return NETDEV_TX_BUSY;
 326
 327         if (cf->can_id & CAN_EFF_FLAG) {
 328                 /* SIDH    | SIDL                 | EIDH   | EIDL
 329                  * 28 - 21 | 20 19 18 x x x 17 16 | 15 - 8 | 7 - 0
 330                  */
 331                 sid = MCBA_SIDL_EXID_MASK;
 332                 /* store 28-18 bits */
 333                 sid |= (cf->can_id & 0x1ffc0000) >> 13;
 334                 /* store 17-16 bits */
 335                 sid |= (cf->can_id & 0x30000) >> 16;
 336                 put_unaligned_be16(sid, &usb_msg.sid);
 337
 338                 /* store 15-0 bits */
 339                 put_unaligned_be16(cf->can_id & 0xffff, &usb_msg.eid);
 340         } else {
 341                 /* SIDH   | SIDL
 342                  * 10 - 3 | 2 1 0 x x x x x
 343                  */
 344                 put_unaligned_be16((cf->can_id & CAN_SFF_MASK) << 5,
 345                                    &usb_msg.sid);
 346                 usb_msg.eid = 0;
 347         }
 348
 349         usb_msg.dlc = cf->can_dlc;
 350
 351         memcpy(usb_msg.data, cf->data, usb_msg.dlc);
 352
 353         if (cf->can_id & CAN_RTR_FLAG)
 354                 usb_msg.dlc |= MCBA_DLC_RTR_MASK;
 355
 356         can_put_echo_skb(skb, priv->netdev, ctx->ndx);
 357
 358         err = mcba_usb_xmit(priv, (struct mcba_usb_msg *)&usb_msg, ctx);
 359         if (err)
 360                 goto xmit_failed;
 361
 362         return NETDEV_TX_OK;
 363
 364 xmit_failed:
 365         can_free_echo_skb(priv->netdev, ctx->ndx);
 366         mcba_usb_free_ctx(ctx);
 367         stats->tx_dropped++;
 368
 369         return NETDEV_TX_OK;
 370 }
 371
 372 /* Send cmd to device */
 373 static void mcba_usb_xmit_cmd(struct mcba_priv *priv,
 374                               struct mcba_usb_msg *usb_msg)
 375 {
 376         struct mcba_usb_ctx *ctx = NULL;
 377         int err;
 378
 379         ctx = mcba_usb_get_free_ctx(priv, NULL);
 380         if (!ctx) {
 381                 netdev_err(priv->netdev,
 382                            "Lack of free ctx. Sending (%d) cmd aborted",
 383                            usb_msg->cmd_id);
 384
 385                 return;
 386         }
 387
 388         err = mcba_usb_xmit(priv, usb_msg, ctx);
 389         if (err)
 390                 netdev_err(priv->netdev, "Failed to send cmd (%d)",
 391                            usb_msg->cmd_id);
 392 }
 393
 394 static void mcba_usb_xmit_change_bitrate(struct mcba_priv *priv, u16 bitrate)
 395 {
 396         struct mcba_usb_msg_change_bitrate usb_msg = {
 397                 .cmd_id = MBCA_CMD_CHANGE_BIT_RATE
 398         };
 399
 400         put_unaligned_be16(bitrate, &usb_msg.bitrate);
 401
 402         mcba_usb_xmit_cmd(priv, (struct mcba_usb_msg *)&usb_msg);
 403 }
 404
 405 static void mcba_usb_xmit_read_fw_ver(struct mcba_priv *priv, u8 pic)
 406 {
 407         struct mcba_usb_msg_fw_ver usb_msg = {
 408                 .cmd_id = MBCA_CMD_READ_FW_VERSION,
 409                 .pic = pic
 410         };
 411
 412         mcba_usb_xmit_cmd(priv, (struct mcba_usb_msg *)&usb_msg);
 413 }
 414
 415 static void mcba_usb_process_can(struct mcba_priv *priv,
 416                                  struct mcba_usb_msg_can *msg)
 417 {
 418         struct can_frame *cf;
 419         struct sk_buff *skb;
 420         struct net_device_stats *stats = &priv->netdev->stats;
 421         u16 sid;
 422
 423         skb = alloc_can_skb(priv->netdev, &cf);
 424         if (!skb)
 425                 return;
 426
 427         sid = get_unaligned_be16(&msg->sid);
 428
 429         if (sid & MCBA_SIDL_EXID_MASK) {
 430                 /* SIDH    | SIDL                 | EIDH   | EIDL
 431                  * 28 - 21 | 20 19 18 x x x 17 16 | 15 - 8 | 7 - 0
 432                  */
 433                 cf->can_id = CAN_EFF_FLAG;
 434
 435                 /* store 28-18 bits */
 436                 cf->can_id |= (sid & 0xffe0) << 13;
 437                 /* store 17-16 bits */
 438                 cf->can_id |= (sid & 3) << 16;
 439                 /* store 15-0 bits */
 440                 cf->can_id |= get_unaligned_be16(&msg->eid);
 441         } else {
 442                 /* SIDH   | SIDL
 443                  * 10 - 3 | 2 1 0 x x x x x
 444                  */
 445                 cf->can_id = (sid & 0xffe0) >> 5;
 446         }
 447
 448         if (msg->dlc & MCBA_DLC_RTR_MASK)
 449                 cf->can_id |= CAN_RTR_FLAG;
 450
 451         cf->can_dlc = get_can_dlc(msg->dlc & MCBA_DLC_MASK);
 452
 453         memcpy(cf->data, msg->data, cf->can_dlc);
 454
 455         stats->rx_packets++;
 456         stats->rx_bytes += cf->can_dlc;
 457
 458         can_led_event(priv->netdev, CAN_LED_EVENT_RX);
 459         netif_rx(skb);
 460 }
 461
 462 static void mcba_usb_process_ka_usb(struct mcba_priv *priv,
 463                                     struct mcba_usb_msg_ka_usb *msg)
 464 {
 465         if (unlikely(priv->usb_ka_first_pass)) {
 466                 netdev_info(priv->netdev, "PIC USB version %hhu.%hhu\n",
 467                             msg->soft_ver_major, msg->soft_ver_minor);
 468
 469                 priv->usb_ka_first_pass = false;
 470         }
 471
 472         if (msg->termination_state)
 473                 priv->can.termination = MCBA_TERMINATION_ENABLED;
 474         else
 475                 priv->can.termination = MCBA_TERMINATION_DISABLED;
 476 }
 477
 478 static u32 convert_can2host_bitrate(struct mcba_usb_msg_ka_can *msg)
 479 {
 480         const u32 bitrate = get_unaligned_be16(&msg->can_bitrate);
 481
 482         if ((bitrate == 33) || (bitrate == 83))
 483                 return bitrate * 1000 + 333;
 484         else
 485                 return bitrate * 1000;
 486 }
 487
 488 static void mcba_usb_process_ka_can(struct mcba_priv *priv,
 489                                     struct mcba_usb_msg_ka_can *msg)
 490 {
 491         if (unlikely(priv->can_ka_first_pass)) {
 492                 netdev_info(priv->netdev, "PIC CAN version %hhu.%hhu\n",
 493                             msg->soft_ver_major, msg->soft_ver_minor);
 494
 495                 priv->can_ka_first_pass = false;
 496         }
 497
 498         if (unlikely(priv->can_speed_check)) {
 499                 const u32 bitrate = convert_can2host_bitrate(msg);
 500
 501                 priv->can_speed_check = false;
 502
 503                 if (bitrate != priv->can.bittiming.bitrate)
 504                         netdev_err(
 505                             priv->netdev,
 506                             "Wrong bitrate reported by the device (%u). Expected %u",
 507                             bitrate, priv->can.bittiming.bitrate);
 508         }
 509
 510         priv->bec.txerr = msg->tx_err_cnt;
 511         priv->bec.rxerr = msg->rx_err_cnt;
 512
 513         if (msg->tx_bus_off)
 514                 priv->can.state = CAN_STATE_BUS_OFF;
 515
 516         else if ((priv->bec.txerr > MCBA_CAN_STATE_ERR_PSV_TH) ||
 517                  (priv->bec.rxerr > MCBA_CAN_STATE_ERR_PSV_TH))
 518                 priv->can.state = CAN_STATE_ERROR_PASSIVE;
 519
 520         else if ((priv->bec.txerr > MCBA_CAN_STATE_WRN_TH) ||
 521                  (priv->bec.rxerr > MCBA_CAN_STATE_WRN_TH))
 522                 priv->can.state = CAN_STATE_ERROR_WARNING;
 523 }
 524
 525 static void mcba_usb_process_rx(struct mcba_priv *priv,
 526                                 struct mcba_usb_msg *msg)
 527 {
 528         switch (msg->cmd_id) {
 529         case MBCA_CMD_I_AM_ALIVE_FROM_CAN:
 530                 mcba_usb_process_ka_can(priv,
 531                                         (struct mcba_usb_msg_ka_can *)msg);
 532                 break;
 533
 534         case MBCA_CMD_I_AM_ALIVE_FROM_USB:
 535                 mcba_usb_process_ka_usb(priv,
 536                                         (struct mcba_usb_msg_ka_usb *)msg);
 537                 break;
 538
 539         case MBCA_CMD_RECEIVE_MESSAGE:
 540                 mcba_usb_process_can(priv, (struct mcba_usb_msg_can *)msg);
 541                 break;
 542
 543         case MBCA_CMD_NOTHING_TO_SEND:
 544                 /* Side effect of communication between PIC_USB and PIC_CAN.
 545                  * PIC_CAN is telling us that it has nothing to send
 546                  */
 547                 break;
 548
 549         case MBCA_CMD_TRANSMIT_MESSAGE_RSP:
 550                 /* Transmission response from the device containing timestamp */
 551                 break;
 552
 553         default:
 554                 netdev_warn(priv->netdev, "Unsupported msg (0x%hhX)",
 555                             msg->cmd_id);
 556                 break;
 557         }
 558 }
 559
 560 /* Callback for reading data from device
 561  *
 562  * Check urb status, call read function and resubmit urb read operation.
 563  */
 564 static void mcba_usb_read_bulk_callback(struct urb *urb)
 565 {
 566         struct mcba_priv *priv = urb->context;
 567         struct net_device *netdev;
 568         int retval;
 569         int pos = 0;
 570
 571         netdev = priv->netdev;
 572
 573         if (!netif_device_present(netdev))
 574                 return;
 575
 576         switch (urb->status) {
 577         case 0: /* success */
 578                 break;
 579
 580         case -ENOENT:
 581         case -EPIPE:
 582         case -EPROTO:
 583         case -ESHUTDOWN:
 584                 return;
 585
 586         default:
 587                 netdev_info(netdev, "Rx URB aborted (%d)\n", urb->status);
 588
 589                 goto resubmit_urb;
 590         }
 591
 592         while (pos < urb->actual_length) {
 593                 struct mcba_usb_msg *msg;
 594
 595                 if (pos + sizeof(struct mcba_usb_msg) > urb->actual_length) {
 596                         netdev_err(priv->netdev, "format error\n");
 597                         break;
 598                 }
 599
 600                 msg = (struct mcba_usb_msg *)(urb->transfer_buffer + pos);
 601                 mcba_usb_process_rx(priv, msg);
 602
 603                 pos += sizeof(struct mcba_usb_msg);
 604         }
 605
 606 resubmit_urb:
 607
 608         usb_fill_bulk_urb(urb, priv->udev,
 609                           priv->rx_pipe,
 610                           urb->transfer_buffer, MCBA_USB_RX_BUFF_SIZE,
 611                           mcba_usb_read_bulk_callback, priv);
 612
 613         retval = usb_submit_urb(urb, GFP_ATOMIC);
 614
 615         if (retval == -ENODEV)
 616                 netif_device_detach(netdev);
 617         else if (retval)
 618                 netdev_err(netdev, "failed resubmitting read bulk urb: %d\n",
 619                            retval);
 620 }
 621
 622 /* Start USB device */
 623 static int mcba_usb_start(struct mcba_priv *priv)
 624 {
 625         struct net_device *netdev = priv->netdev;
 626         int err, i;
 627
 628         mcba_init_ctx(priv);
 629
 630         for (i = 0; i < MCBA_MAX_RX_URBS; i++) {
 631                 struct urb *urb = NULL;
 632                 u8 *buf;
 633                 dma_addr_t buf_dma;
 634
 635                 /* create a URB, and a buffer for it */
 636                 urb = usb_alloc_urb(0, GFP_KERNEL);
 637                 if (!urb) {
 638                         err = -ENOMEM;
 639                         break;
 640                 }
 641
 642                 buf = usb_alloc_coherent(priv->udev, MCBA_USB_RX_BUFF_SIZE,
 643                                          GFP_KERNEL, &buf_dma);
 644                 if (!buf) {
 645                         netdev_err(netdev, "No memory left for USB buffer\n");
 646                         usb_free_urb(urb);
 647                         err = -ENOMEM;
 648                         break;
 649                 }
 650
 651                 urb->transfer_dma = buf_dma;
 652
 653                 usb_fill_bulk_urb(urb, priv->udev,
 654                                   priv->rx_pipe,
 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, buf_dma);
 665                         usb_free_urb(urb);
 666                         break;
 667                 }
 668
 669                 priv->rxbuf[i] = buf;
 670                 priv->rxbuf_dma[i] = buf_dma;
 671
 672                 /* Drop reference, USB core will take care of freeing it */
 673                 usb_free_urb(urb);
 674         }
 675
 676         /* Did we submit any URBs */
 677         if (i == 0) {
 678                 netdev_warn(netdev, "couldn't setup read URBs\n");
 679                 return err;
 680         }
 681
 682         /* Warn if we've couldn't transmit all the URBs */
 683         if (i < MCBA_MAX_RX_URBS)
 684                 netdev_warn(netdev, "rx performance may be slow\n");
 685
 686         mcba_usb_xmit_read_fw_ver(priv, MCBA_VER_REQ_USB);
 687         mcba_usb_xmit_read_fw_ver(priv, MCBA_VER_REQ_CAN);
 688
 689         return err;
 690 }
 691
 692 /* Open USB device */
 693 static int mcba_usb_open(struct net_device *netdev)
 694 {
 695         struct mcba_priv *priv = netdev_priv(netdev);
 696         int err;
 697
 698         /* common open */
 699         err = open_candev(netdev);
 700         if (err)
 701                 return err;
 702
 703         priv->can_speed_check = true;
 704         priv->can.state = CAN_STATE_ERROR_ACTIVE;
 705
 706         can_led_event(netdev, CAN_LED_EVENT_OPEN);
 707         netif_start_queue(netdev);
 708
 709         return 0;
 710 }
 711
 712 static void mcba_urb_unlink(struct mcba_priv *priv)
 713 {
 714         int i;
 715
 716         usb_kill_anchored_urbs(&priv->rx_submitted);
 717
 718         for (i = 0; i < MCBA_MAX_RX_URBS; ++i)
 719                 usb_free_coherent(priv->udev, MCBA_USB_RX_BUFF_SIZE,
 720                                   priv->rxbuf[i], priv->rxbuf_dma[i]);
 721
 722         usb_kill_anchored_urbs(&priv->tx_submitted);
 723 }
 724
 725 /* Close USB device */
 726 static int mcba_usb_close(struct net_device *netdev)
 727 {
 728         struct mcba_priv *priv = netdev_priv(netdev);
 729
 730         priv->can.state = CAN_STATE_STOPPED;
 731
 732         netif_stop_queue(netdev);
 733
 734         /* Stop polling */
 735         mcba_urb_unlink(priv);
 736
 737         close_candev(netdev);
 738         can_led_event(netdev, CAN_LED_EVENT_STOP);
 739
 740         return 0;
 741 }
 742
 743 /* Set network device mode
 744  *
 745  * Maybe we should leave this function empty, because the device
 746  * set mode variable with open command.
 747  */
 748 static int mcba_net_set_mode(struct net_device *netdev, enum can_mode mode)
 749 {
 750         return 0;
 751 }
 752
 753 static int mcba_net_get_berr_counter(const struct net_device *netdev,
 754                                      struct can_berr_counter *bec)
 755 {
 756         struct mcba_priv *priv = netdev_priv(netdev);
 757
 758         bec->txerr = priv->bec.txerr;
 759         bec->rxerr = priv->bec.rxerr;
 760
 761         return 0;
 762 }
 763
 764 static const struct net_device_ops mcba_netdev_ops = {
 765         .ndo_open = mcba_usb_open,
 766         .ndo_stop = mcba_usb_close,
 767         .ndo_start_xmit = mcba_usb_start_xmit,
 768 };
 769
 770 /* Microchip CANBUS has hardcoded bittiming values by default.
 771  * This function sends request via USB to change the speed and align bittiming
 772  * values for presentation purposes only
 773  */
 774 static int mcba_net_set_bittiming(struct net_device *netdev)
 775 {
 776         struct mcba_priv *priv = netdev_priv(netdev);
 777         const u16 bitrate_kbps = priv->can.bittiming.bitrate / 1000;
 778
 779         mcba_usb_xmit_change_bitrate(priv, bitrate_kbps);
 780
 781         return 0;
 782 }
 783
 784 static int mcba_set_termination(struct net_device *netdev, u16 term)
 785 {
 786         struct mcba_priv *priv = netdev_priv(netdev);
 787         struct mcba_usb_msg_termination usb_msg = {
 788                 .cmd_id = MBCA_CMD_SETUP_TERMINATION_RESISTANCE
 789         };
 790
 791         if (term == MCBA_TERMINATION_ENABLED)
 792                 usb_msg.termination = 1;
 793         else
 794                 usb_msg.termination = 0;
 795
 796         mcba_usb_xmit_cmd(priv, (struct mcba_usb_msg *)&usb_msg);
 797
 798         return 0;
 799 }
 800
 801 static int mcba_usb_probe(struct usb_interface *intf,
 802                           const struct usb_device_id *id)
 803 {
 804         struct net_device *netdev;
 805         struct mcba_priv *priv;
 806         int err;
 807         struct usb_device *usbdev = interface_to_usbdev(intf);
 808         struct usb_endpoint_descriptor *in, *out;
 809
 810         err = usb_find_common_endpoints(intf->cur_altsetting, &in, &out, NULL, NULL);
 811         if (err) {
 812                 dev_err(&intf->dev, "Can't find endpoints\n");
 813                 return err;
 814         }
 815
 816         netdev = alloc_candev(sizeof(struct mcba_priv), MCBA_MAX_TX_URBS);
 817         if (!netdev) {
 818                 dev_err(&intf->dev, "Couldn't alloc candev\n");
 819                 return -ENOMEM;
 820         }
 821
 822         priv = netdev_priv(netdev);
 823
 824         priv->udev = usbdev;
 825         priv->netdev = netdev;
 826         priv->usb_ka_first_pass = true;
 827         priv->can_ka_first_pass = true;
 828         priv->can_speed_check = false;
 829
 830         init_usb_anchor(&priv->rx_submitted);
 831         init_usb_anchor(&priv->tx_submitted);
 832
 833         usb_set_intfdata(intf, priv);
 834
 835         /* Init CAN device */
 836         priv->can.state = CAN_STATE_STOPPED;
 837         priv->can.termination_const = mcba_termination;
 838         priv->can.termination_const_cnt = ARRAY_SIZE(mcba_termination);
 839         priv->can.bitrate_const = mcba_bitrate;
 840         priv->can.bitrate_const_cnt = ARRAY_SIZE(mcba_bitrate);
 841
 842         priv->can.do_set_termination = mcba_set_termination;
 843         priv->can.do_set_mode = mcba_net_set_mode;
 844         priv->can.do_get_berr_counter = mcba_net_get_berr_counter;
 845         priv->can.do_set_bittiming = mcba_net_set_bittiming;
 846
 847         netdev->netdev_ops = &mcba_netdev_ops;
 848
 849         netdev->flags |= IFF_ECHO; /* we support local echo */
 850
 851         SET_NETDEV_DEV(netdev, &intf->dev);
 852
 853         err = register_candev(netdev);
 854         if (err) {
 855                 netdev_err(netdev, "couldn't register CAN device: %d\n", err);
 856
 857                 goto cleanup_free_candev;
 858         }
 859
 860         priv->rx_pipe = usb_rcvbulkpipe(priv->udev, in->bEndpointAddress);
 861         priv->tx_pipe = usb_sndbulkpipe(priv->udev, out->bEndpointAddress);
 862
 863         devm_can_led_init(netdev);
 864
 865         /* Start USB dev only if we have successfully registered CAN device */
 866         err = mcba_usb_start(priv);
 867         if (err) {
 868                 if (err == -ENODEV)
 869                         netif_device_detach(priv->netdev);
 870
 871                 netdev_warn(netdev, "couldn't start device: %d\n", err);
 872
 873                 goto cleanup_unregister_candev;
 874         }
 875
 876         dev_info(&intf->dev, "Microchip CAN BUS Analyzer connected\n");
 877
 878         return 0;
 879
 880 cleanup_unregister_candev:
 881         unregister_candev(priv->netdev);
 882
 883 cleanup_free_candev:
 884         free_candev(netdev);
 885
 886         return err;
 887 }
 888
 889 /* Called by the usb core when driver is unloaded or device is removed */
 890 static void mcba_usb_disconnect(struct usb_interface *intf)
 891 {
 892         struct mcba_priv *priv = usb_get_intfdata(intf);
 893
 894         usb_set_intfdata(intf, NULL);
 895
 896         netdev_info(priv->netdev, "device disconnected\n");
 897
 898         unregister_candev(priv->netdev);
 899         mcba_urb_unlink(priv);
 900         free_candev(priv->netdev);
 901 }
 902
 903 static struct usb_driver mcba_usb_driver = {
 904         .name = MCBA_MODULE_NAME,
 905         .probe = mcba_usb_probe,
 906         .disconnect = mcba_usb_disconnect,
 907         .id_table = mcba_usb_table,
 908 };
 909
 910 module_usb_driver(mcba_usb_driver);
 911
 912 MODULE_AUTHOR("Remigiusz Kołłątaj <remigiusz.kollataj@mobica.com>");
 913 MODULE_DESCRIPTION("SocketCAN driver for Microchip CAN BUS Analyzer Tool");
 914 MODULE_LICENSE("GPL v2");