drivers/net/can/usb/ems_usb.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * CAN driver for EMS Dr. Thomas Wuensche CPC-USB/ARM7
   4  *
   5  * Copyright (C) 2004-2009 EMS Dr. Thomas Wuensche
   6  */
   7 #include <linux/signal.h>
   8 #include <linux/slab.h>
   9 #include <linux/module.h>
  10 #include <linux/netdevice.h>
  11 #include <linux/usb.h>
  12
  13 #include <linux/can.h>
  14 #include <linux/can/dev.h>
  15 #include <linux/can/error.h>
  16
  17 MODULE_AUTHOR("Sebastian Haas <haas@ems-wuensche.com>");
  18 MODULE_DESCRIPTION("CAN driver for EMS Dr. Thomas Wuensche CAN/USB interfaces");
  19 MODULE_LICENSE("GPL v2");
  20
  21 /* Control-Values for CPC_Control() Command Subject Selection */
  22 #define CONTR_CAN_MESSAGE 0x04
  23 #define CONTR_CAN_STATE   0x0C
  24 #define CONTR_BUS_ERROR   0x1C
  25
  26 /* Control Command Actions */
  27 #define CONTR_CONT_OFF 0
  28 #define CONTR_CONT_ON  1
  29 #define CONTR_ONCE     2
  30
  31 /* Messages from CPC to PC */
  32 #define CPC_MSG_TYPE_CAN_FRAME       1  /* CAN data frame */
  33 #define CPC_MSG_TYPE_RTR_FRAME       8  /* CAN remote frame */
  34 #define CPC_MSG_TYPE_CAN_PARAMS      12 /* Actual CAN parameters */
  35 #define CPC_MSG_TYPE_CAN_STATE       14 /* CAN state message */
  36 #define CPC_MSG_TYPE_EXT_CAN_FRAME   16 /* Extended CAN data frame */
  37 #define CPC_MSG_TYPE_EXT_RTR_FRAME   17 /* Extended remote frame */
  38 #define CPC_MSG_TYPE_CONTROL         19 /* change interface behavior */
  39 #define CPC_MSG_TYPE_CONFIRM         20 /* command processed confirmation */
  40 #define CPC_MSG_TYPE_OVERRUN         21 /* overrun events */
  41 #define CPC_MSG_TYPE_CAN_FRAME_ERROR 23 /* detected bus errors */
  42 #define CPC_MSG_TYPE_ERR_COUNTER     25 /* RX/TX error counter */
  43
  44 /* Messages from the PC to the CPC interface  */
  45 #define CPC_CMD_TYPE_CAN_FRAME     1   /* CAN data frame */
  46 #define CPC_CMD_TYPE_CONTROL       3   /* control of interface behavior */
  47 #define CPC_CMD_TYPE_CAN_PARAMS    6   /* set CAN parameters */
  48 #define CPC_CMD_TYPE_RTR_FRAME     13  /* CAN remote frame */
  49 #define CPC_CMD_TYPE_CAN_STATE     14  /* CAN state message */
  50 #define CPC_CMD_TYPE_EXT_CAN_FRAME 15  /* Extended CAN data frame */
  51 #define CPC_CMD_TYPE_EXT_RTR_FRAME 16  /* Extended CAN remote frame */
  52 #define CPC_CMD_TYPE_CAN_EXIT      200 /* exit the CAN */
  53
  54 #define CPC_CMD_TYPE_INQ_ERR_COUNTER 25 /* request the CAN error counters */
  55 #define CPC_CMD_TYPE_CLEAR_MSG_QUEUE 8  /* clear CPC_MSG queue */
  56 #define CPC_CMD_TYPE_CLEAR_CMD_QUEUE 28 /* clear CPC_CMD queue */
  57
  58 #define CPC_CC_TYPE_SJA1000 2 /* Philips basic CAN controller */
  59
  60 #define CPC_CAN_ECODE_ERRFRAME 0x01 /* Ecode type */
  61
  62 /* Overrun types */
  63 #define CPC_OVR_EVENT_CAN       0x01
  64 #define CPC_OVR_EVENT_CANSTATE  0x02
  65 #define CPC_OVR_EVENT_BUSERROR  0x04
  66
  67 /*
  68  * If the CAN controller lost a message we indicate it with the highest bit
  69  * set in the count field.
  70  */
  71 #define CPC_OVR_HW 0x80
  72
  73 /* Size of the "struct ems_cpc_msg" without the union */
  74 #define CPC_MSG_HEADER_LEN   11
  75 #define CPC_CAN_MSG_MIN_SIZE 5
  76
  77 /* Define these values to match your devices */
  78 #define USB_CPCUSB_VENDOR_ID 0x12D6
  79
  80 #define USB_CPCUSB_ARM7_PRODUCT_ID 0x0444
  81
  82 /* Mode register NXP LPC2119/SJA1000 CAN Controller */
  83 #define SJA1000_MOD_NORMAL 0x00
  84 #define SJA1000_MOD_RM     0x01
  85
  86 /* ECC register NXP LPC2119/SJA1000 CAN Controller */
  87 #define SJA1000_ECC_SEG   0x1F
  88 #define SJA1000_ECC_DIR   0x20
  89 #define SJA1000_ECC_ERR   0x06
  90 #define SJA1000_ECC_BIT   0x00
  91 #define SJA1000_ECC_FORM  0x40
  92 #define SJA1000_ECC_STUFF 0x80
  93 #define SJA1000_ECC_MASK  0xc0
  94
  95 /* Status register content */
  96 #define SJA1000_SR_BS 0x80
  97 #define SJA1000_SR_ES 0x40
  98
  99 #define SJA1000_DEFAULT_OUTPUT_CONTROL 0xDA
 100
 101 /*
 102  * The device actually uses a 16MHz clock to generate the CAN clock
 103  * but it expects SJA1000 bit settings based on 8MHz (is internally
 104  * converted).
 105  */
 106 #define EMS_USB_ARM7_CLOCK 8000000
 107
 108 #define CPC_TX_QUEUE_TRIGGER_LOW        25
 109 #define CPC_TX_QUEUE_TRIGGER_HIGH       35
 110
 111 /*
 112  * CAN-Message representation in a CPC_MSG. Message object type is
 113  * CPC_MSG_TYPE_CAN_FRAME or CPC_MSG_TYPE_RTR_FRAME or
 114  * CPC_MSG_TYPE_EXT_CAN_FRAME or CPC_MSG_TYPE_EXT_RTR_FRAME.
 115  */
 116 struct cpc_can_msg {
 117         __le32 id;
 118         u8 length;
 119         u8 msg[8];
 120 };
 121
 122 /* Representation of the CAN parameters for the SJA1000 controller */
 123 struct cpc_sja1000_params {
 124         u8 mode;
 125         u8 acc_code0;
 126         u8 acc_code1;
 127         u8 acc_code2;
 128         u8 acc_code3;
 129         u8 acc_mask0;
 130         u8 acc_mask1;
 131         u8 acc_mask2;
 132         u8 acc_mask3;
 133         u8 btr0;
 134         u8 btr1;
 135         u8 outp_contr;
 136 };
 137
 138 /* CAN params message representation */
 139 struct cpc_can_params {
 140         u8 cc_type;
 141
 142         /* Will support M16C CAN controller in the future */
 143         union {
 144                 struct cpc_sja1000_params sja1000;
 145         } cc_params;
 146 };
 147
 148 /* Structure for confirmed message handling */
 149 struct cpc_confirm {
 150         u8 error; /* error code */
 151 };
 152
 153 /* Structure for overrun conditions */
 154 struct cpc_overrun {
 155         u8 event;
 156         u8 count;
 157 };
 158
 159 /* SJA1000 CAN errors (compatible to NXP LPC2119) */
 160 struct cpc_sja1000_can_error {
 161         u8 ecc;
 162         u8 rxerr;
 163         u8 txerr;
 164 };
 165
 166 /* structure for CAN error conditions */
 167 struct cpc_can_error {
 168         u8 ecode;
 169
 170         struct {
 171                 u8 cc_type;
 172
 173                 /* Other controllers may also provide error code capture regs */
 174                 union {
 175                         struct cpc_sja1000_can_error sja1000;
 176                 } regs;
 177         } cc;
 178 };
 179
 180 /*
 181  * Structure containing RX/TX error counter. This structure is used to request
 182  * the values of the CAN controllers TX and RX error counter.
 183  */
 184 struct cpc_can_err_counter {
 185         u8 rx;
 186         u8 tx;
 187 };
 188
 189 /* Main message type used between library and application */
 190 struct __packed ems_cpc_msg {
 191         u8 type;        /* type of message */
 192         u8 length;      /* length of data within union 'msg' */
 193         u8 msgid;       /* confirmation handle */
 194         __le32 ts_sec;  /* timestamp in seconds */
 195         __le32 ts_nsec; /* timestamp in nano seconds */
 196
 197         union __packed {
 198                 u8 generic[64];
 199                 struct cpc_can_msg can_msg;
 200                 struct cpc_can_params can_params;
 201                 struct cpc_confirm confirmation;
 202                 struct cpc_overrun overrun;
 203                 struct cpc_can_error error;
 204                 struct cpc_can_err_counter err_counter;
 205                 u8 can_state;
 206         } msg;
 207 };
 208
 209 /*
 210  * Table of devices that work with this driver
 211  * NOTE: This driver supports only CPC-USB/ARM7 (LPC2119) yet.
 212  */
 213 static struct usb_device_id ems_usb_table[] = {
 214         {USB_DEVICE(USB_CPCUSB_VENDOR_ID, USB_CPCUSB_ARM7_PRODUCT_ID)},
 215         {} /* Terminating entry */
 216 };
 217
 218 MODULE_DEVICE_TABLE(usb, ems_usb_table);
 219
 220 #define RX_BUFFER_SIZE      64
 221 #define CPC_HEADER_SIZE     4
 222 #define INTR_IN_BUFFER_SIZE 4
 223
 224 #define MAX_RX_URBS 10
 225 #define MAX_TX_URBS 10
 226
 227 struct ems_usb;
 228
 229 struct ems_tx_urb_context {
 230         struct ems_usb *dev;
 231
 232         u32 echo_index;
 233         u8 dlc;
 234 };
 235
 236 struct ems_usb {
 237         struct can_priv can; /* must be the first member */
 238
 239         struct sk_buff *echo_skb[MAX_TX_URBS];
 240
 241         struct usb_device *udev;
 242         struct net_device *netdev;
 243
 244         atomic_t active_tx_urbs;
 245         struct usb_anchor tx_submitted;
 246         struct ems_tx_urb_context tx_contexts[MAX_TX_URBS];
 247
 248         struct usb_anchor rx_submitted;
 249
 250         struct urb *intr_urb;
 251
 252         u8 *tx_msg_buffer;
 253
 254         u8 *intr_in_buffer;
 255         unsigned int free_slots; /* remember number of available slots */
 256
 257         struct ems_cpc_msg active_params; /* active controller parameters */
 258         void *rxbuf[MAX_RX_URBS];
 259         dma_addr_t rxbuf_dma[MAX_RX_URBS];
 260 };
 261
 262 static void ems_usb_read_interrupt_callback(struct urb *urb)
 263 {
 264         struct ems_usb *dev = urb->context;
 265         struct net_device *netdev = dev->netdev;
 266         int err;
 267
 268         if (!netif_device_present(netdev))
 269                 return;
 270
 271         switch (urb->status) {
 272         case 0:
 273                 dev->free_slots = dev->intr_in_buffer[1];
 274                 if (dev->free_slots > CPC_TX_QUEUE_TRIGGER_HIGH &&
 275                     netif_queue_stopped(netdev))
 276                         netif_wake_queue(netdev);
 277                 break;
 278
 279         case -ECONNRESET: /* unlink */
 280         case -ENOENT:
 281         case -EPIPE:
 282         case -EPROTO:
 283         case -ESHUTDOWN:
 284                 return;
 285
 286         default:
 287                 netdev_info(netdev, "Rx interrupt aborted %d\n", urb->status);
 288                 break;
 289         }
 290
 291         err = usb_submit_urb(urb, GFP_ATOMIC);
 292
 293         if (err == -ENODEV)
 294                 netif_device_detach(netdev);
 295         else if (err)
 296                 netdev_err(netdev, "failed resubmitting intr urb: %d\n", err);
 297 }
 298
 299 static void ems_usb_rx_can_msg(struct ems_usb *dev, struct ems_cpc_msg *msg)
 300 {
 301         struct can_frame *cf;
 302         struct sk_buff *skb;
 303         int i;
 304         struct net_device_stats *stats = &dev->netdev->stats;
 305
 306         skb = alloc_can_skb(dev->netdev, &cf);
 307         if (skb == NULL)
 308                 return;
 309
 310         cf->can_id = le32_to_cpu(msg->msg.can_msg.id);
 311         cf->can_dlc = get_can_dlc(msg->msg.can_msg.length & 0xF);
 312
 313         if (msg->type == CPC_MSG_TYPE_EXT_CAN_FRAME ||
 314             msg->type == CPC_MSG_TYPE_EXT_RTR_FRAME)
 315                 cf->can_id |= CAN_EFF_FLAG;
 316
 317         if (msg->type == CPC_MSG_TYPE_RTR_FRAME ||
 318             msg->type == CPC_MSG_TYPE_EXT_RTR_FRAME) {
 319                 cf->can_id |= CAN_RTR_FLAG;
 320         } else {
 321                 for (i = 0; i < cf->can_dlc; i++)
 322                         cf->data[i] = msg->msg.can_msg.msg[i];
 323         }
 324
 325         stats->rx_packets++;
 326         stats->rx_bytes += cf->can_dlc;
 327         netif_rx(skb);
 328 }
 329
 330 static void ems_usb_rx_err(struct ems_usb *dev, struct ems_cpc_msg *msg)
 331 {
 332         struct can_frame *cf;
 333         struct sk_buff *skb;
 334         struct net_device_stats *stats = &dev->netdev->stats;
 335
 336         skb = alloc_can_err_skb(dev->netdev, &cf);
 337         if (skb == NULL)
 338                 return;
 339
 340         if (msg->type == CPC_MSG_TYPE_CAN_STATE) {
 341                 u8 state = msg->msg.can_state;
 342
 343                 if (state & SJA1000_SR_BS) {
 344                         dev->can.state = CAN_STATE_BUS_OFF;
 345                         cf->can_id |= CAN_ERR_BUSOFF;
 346
 347                         dev->can.can_stats.bus_off++;
 348                         can_bus_off(dev->netdev);
 349                 } else if (state & SJA1000_SR_ES) {
 350                         dev->can.state = CAN_STATE_ERROR_WARNING;
 351                         dev->can.can_stats.error_warning++;
 352                 } else {
 353                         dev->can.state = CAN_STATE_ERROR_ACTIVE;
 354                         dev->can.can_stats.error_passive++;
 355                 }
 356         } else if (msg->type == CPC_MSG_TYPE_CAN_FRAME_ERROR) {
 357                 u8 ecc = msg->msg.error.cc.regs.sja1000.ecc;
 358                 u8 txerr = msg->msg.error.cc.regs.sja1000.txerr;
 359                 u8 rxerr = msg->msg.error.cc.regs.sja1000.rxerr;
 360
 361                 /* bus error interrupt */
 362                 dev->can.can_stats.bus_error++;
 363                 stats->rx_errors++;
 364
 365                 cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
 366
 367                 switch (ecc & SJA1000_ECC_MASK) {
 368                 case SJA1000_ECC_BIT:
 369                         cf->data[2] |= CAN_ERR_PROT_BIT;
 370                         break;
 371                 case SJA1000_ECC_FORM:
 372                         cf->data[2] |= CAN_ERR_PROT_FORM;
 373                         break;
 374                 case SJA1000_ECC_STUFF:
 375                         cf->data[2] |= CAN_ERR_PROT_STUFF;
 376                         break;
 377                 default:
 378                         cf->data[3] = ecc & SJA1000_ECC_SEG;
 379                         break;
 380                 }
 381
 382                 /* Error occurred during transmission? */
 383                 if ((ecc & SJA1000_ECC_DIR) == 0)
 384                         cf->data[2] |= CAN_ERR_PROT_TX;
 385
 386                 if (dev->can.state == CAN_STATE_ERROR_WARNING ||
 387                     dev->can.state == CAN_STATE_ERROR_PASSIVE) {
 388                         cf->can_id |= CAN_ERR_CRTL;
 389                         cf->data[1] = (txerr > rxerr) ?
 390                             CAN_ERR_CRTL_TX_PASSIVE : CAN_ERR_CRTL_RX_PASSIVE;
 391                 }
 392         } else if (msg->type == CPC_MSG_TYPE_OVERRUN) {
 393                 cf->can_id |= CAN_ERR_CRTL;
 394                 cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
 395
 396                 stats->rx_over_errors++;
 397                 stats->rx_errors++;
 398         }
 399
 400         stats->rx_packets++;
 401         stats->rx_bytes += cf->can_dlc;
 402         netif_rx(skb);
 403 }
 404
 405 /*
 406  * callback for bulk IN urb
 407  */
 408 static void ems_usb_read_bulk_callback(struct urb *urb)
 409 {
 410         struct ems_usb *dev = urb->context;
 411         struct net_device *netdev;
 412         int retval;
 413
 414         netdev = dev->netdev;
 415
 416         if (!netif_device_present(netdev))
 417                 return;
 418
 419         switch (urb->status) {
 420         case 0: /* success */
 421                 break;
 422
 423         case -ENOENT:
 424                 return;
 425
 426         default:
 427                 netdev_info(netdev, "Rx URB aborted (%d)\n", urb->status);
 428                 goto resubmit_urb;
 429         }
 430
 431         if (urb->actual_length > CPC_HEADER_SIZE) {
 432                 struct ems_cpc_msg *msg;
 433                 u8 *ibuf = urb->transfer_buffer;
 434                 u8 msg_count, start;
 435
 436                 msg_count = ibuf[0] & ~0x80;
 437
 438                 start = CPC_HEADER_SIZE;
 439
 440                 while (msg_count) {
 441                         msg = (struct ems_cpc_msg *)&ibuf[start];
 442
 443                         switch (msg->type) {
 444                         case CPC_MSG_TYPE_CAN_STATE:
 445                                 /* Process CAN state changes */
 446                                 ems_usb_rx_err(dev, msg);
 447                                 break;
 448
 449                         case CPC_MSG_TYPE_CAN_FRAME:
 450                         case CPC_MSG_TYPE_EXT_CAN_FRAME:
 451                         case CPC_MSG_TYPE_RTR_FRAME:
 452                         case CPC_MSG_TYPE_EXT_RTR_FRAME:
 453                                 ems_usb_rx_can_msg(dev, msg);
 454                                 break;
 455
 456                         case CPC_MSG_TYPE_CAN_FRAME_ERROR:
 457                                 /* Process errorframe */
 458                                 ems_usb_rx_err(dev, msg);
 459                                 break;
 460
 461                         case CPC_MSG_TYPE_OVERRUN:
 462                                 /* Message lost while receiving */
 463                                 ems_usb_rx_err(dev, msg);
 464                                 break;
 465                         }
 466
 467                         start += CPC_MSG_HEADER_LEN + msg->length;
 468                         msg_count--;
 469
 470                         if (start > urb->transfer_buffer_length) {
 471                                 netdev_err(netdev, "format error\n");
 472                                 break;
 473                         }
 474                 }
 475         }
 476
 477 resubmit_urb:
 478         usb_fill_bulk_urb(urb, dev->udev, usb_rcvbulkpipe(dev->udev, 2),
 479                           urb->transfer_buffer, RX_BUFFER_SIZE,
 480                           ems_usb_read_bulk_callback, dev);
 481
 482         retval = usb_submit_urb(urb, GFP_ATOMIC);
 483
 484         if (retval == -ENODEV)
 485                 netif_device_detach(netdev);
 486         else if (retval)
 487                 netdev_err(netdev,
 488                            "failed resubmitting read bulk urb: %d\n", retval);
 489 }
 490
 491 /*
 492  * callback for bulk IN urb
 493  */
 494 static void ems_usb_write_bulk_callback(struct urb *urb)
 495 {
 496         struct ems_tx_urb_context *context = urb->context;
 497         struct ems_usb *dev;
 498         struct net_device *netdev;
 499
 500         BUG_ON(!context);
 501
 502         dev = context->dev;
 503         netdev = dev->netdev;
 504
 505         /* free up our allocated buffer */
 506         usb_free_coherent(urb->dev, urb->transfer_buffer_length,
 507                           urb->transfer_buffer, urb->transfer_dma);
 508
 509         atomic_dec(&dev->active_tx_urbs);
 510
 511         if (!netif_device_present(netdev))
 512                 return;
 513
 514         if (urb->status)
 515                 netdev_info(netdev, "Tx URB aborted (%d)\n", urb->status);
 516
 517         netif_trans_update(netdev);
 518
 519         /* transmission complete interrupt */
 520         netdev->stats.tx_packets++;
 521         netdev->stats.tx_bytes += context->dlc;
 522
 523         can_get_echo_skb(netdev, context->echo_index);
 524
 525         /* Release context */
 526         context->echo_index = MAX_TX_URBS;
 527
 528 }
 529
 530 /*
 531  * Send the given CPC command synchronously
 532  */
 533 static int ems_usb_command_msg(struct ems_usb *dev, struct ems_cpc_msg *msg)
 534 {
 535         int actual_length;
 536
 537         /* Copy payload */
 538         memcpy(&dev->tx_msg_buffer[CPC_HEADER_SIZE], msg,
 539                msg->length + CPC_MSG_HEADER_LEN);
 540
 541         /* Clear header */
 542         memset(&dev->tx_msg_buffer[0], 0, CPC_HEADER_SIZE);
 543
 544         return usb_bulk_msg(dev->udev, usb_sndbulkpipe(dev->udev, 2),
 545                             &dev->tx_msg_buffer[0],
 546                             msg->length + CPC_MSG_HEADER_LEN + CPC_HEADER_SIZE,
 547                             &actual_length, 1000);
 548 }
 549
 550 /*
 551  * Change CAN controllers' mode register
 552  */
 553 static int ems_usb_write_mode(struct ems_usb *dev, u8 mode)
 554 {
 555         dev->active_params.msg.can_params.cc_params.sja1000.mode = mode;
 556
 557         return ems_usb_command_msg(dev, &dev->active_params);
 558 }
 559
 560 /*
 561  * Send a CPC_Control command to change behaviour when interface receives a CAN
 562  * message, bus error or CAN state changed notifications.
 563  */
 564 static int ems_usb_control_cmd(struct ems_usb *dev, u8 val)
 565 {
 566         struct ems_cpc_msg cmd;
 567
 568         cmd.type = CPC_CMD_TYPE_CONTROL;
 569         cmd.length = CPC_MSG_HEADER_LEN + 1;
 570
 571         cmd.msgid = 0;
 572
 573         cmd.msg.generic[0] = val;
 574
 575         return ems_usb_command_msg(dev, &cmd);
 576 }
 577
 578 /*
 579  * Start interface
 580  */
 581 static int ems_usb_start(struct ems_usb *dev)
 582 {
 583         struct net_device *netdev = dev->netdev;
 584         int err, i;
 585
 586         dev->intr_in_buffer[0] = 0;
 587         dev->free_slots = 50; /* initial size */
 588
 589         for (i = 0; i < MAX_RX_URBS; i++) {
 590                 struct urb *urb = NULL;
 591                 u8 *buf = NULL;
 592                 dma_addr_t buf_dma;
 593
 594                 /* create a URB, and a buffer for it */
 595                 urb = usb_alloc_urb(0, GFP_KERNEL);
 596                 if (!urb) {
 597                         err = -ENOMEM;
 598                         break;
 599                 }
 600
 601                 buf = usb_alloc_coherent(dev->udev, RX_BUFFER_SIZE, GFP_KERNEL,
 602                                          &buf_dma);
 603                 if (!buf) {
 604                         netdev_err(netdev, "No memory left for USB buffer\n");
 605                         usb_free_urb(urb);
 606                         err = -ENOMEM;
 607                         break;
 608                 }
 609
 610                 urb->transfer_dma = buf_dma;
 611
 612                 usb_fill_bulk_urb(urb, dev->udev, usb_rcvbulkpipe(dev->udev, 2),
 613                                   buf, RX_BUFFER_SIZE,
 614                                   ems_usb_read_bulk_callback, dev);
 615                 urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 616                 usb_anchor_urb(urb, &dev->rx_submitted);
 617
 618                 err = usb_submit_urb(urb, GFP_KERNEL);
 619                 if (err) {
 620                         usb_unanchor_urb(urb);
 621                         usb_free_coherent(dev->udev, RX_BUFFER_SIZE, buf,
 622                                           urb->transfer_dma);
 623                         usb_free_urb(urb);
 624                         break;
 625                 }
 626
 627                 dev->rxbuf[i] = buf;
 628                 dev->rxbuf_dma[i] = buf_dma;
 629
 630                 /* Drop reference, USB core will take care of freeing it */
 631                 usb_free_urb(urb);
 632         }
 633
 634         /* Did we submit any URBs */
 635         if (i == 0) {
 636                 netdev_warn(netdev, "couldn't setup read URBs\n");
 637                 return err;
 638         }
 639
 640         /* Warn if we've couldn't transmit all the URBs */
 641         if (i < MAX_RX_URBS)
 642                 netdev_warn(netdev, "rx performance may be slow\n");
 643
 644         /* Setup and start interrupt URB */
 645         usb_fill_int_urb(dev->intr_urb, dev->udev,
 646                          usb_rcvintpipe(dev->udev, 1),
 647                          dev->intr_in_buffer,
 648                          INTR_IN_BUFFER_SIZE,
 649                          ems_usb_read_interrupt_callback, dev, 1);
 650
 651         err = usb_submit_urb(dev->intr_urb, GFP_KERNEL);
 652         if (err) {
 653                 netdev_warn(netdev, "intr URB submit failed: %d\n", err);
 654
 655                 return err;
 656         }
 657
 658         /* CPC-USB will transfer received message to host */
 659         err = ems_usb_control_cmd(dev, CONTR_CAN_MESSAGE | CONTR_CONT_ON);
 660         if (err)
 661                 goto failed;
 662
 663         /* CPC-USB will transfer CAN state changes to host */
 664         err = ems_usb_control_cmd(dev, CONTR_CAN_STATE | CONTR_CONT_ON);
 665         if (err)
 666                 goto failed;
 667
 668         /* CPC-USB will transfer bus errors to host */
 669         err = ems_usb_control_cmd(dev, CONTR_BUS_ERROR | CONTR_CONT_ON);
 670         if (err)
 671                 goto failed;
 672
 673         err = ems_usb_write_mode(dev, SJA1000_MOD_NORMAL);
 674         if (err)
 675                 goto failed;
 676
 677         dev->can.state = CAN_STATE_ERROR_ACTIVE;
 678
 679         return 0;
 680
 681 failed:
 682         netdev_warn(netdev, "couldn't submit control: %d\n", err);
 683
 684         return err;
 685 }
 686
 687 static void unlink_all_urbs(struct ems_usb *dev)
 688 {
 689         int i;
 690
 691         usb_unlink_urb(dev->intr_urb);
 692
 693         usb_kill_anchored_urbs(&dev->rx_submitted);
 694
 695         for (i = 0; i < MAX_RX_URBS; ++i)
 696                 usb_free_coherent(dev->udev, RX_BUFFER_SIZE,
 697                                   dev->rxbuf[i], dev->rxbuf_dma[i]);
 698
 699         usb_kill_anchored_urbs(&dev->tx_submitted);
 700         atomic_set(&dev->active_tx_urbs, 0);
 701
 702         for (i = 0; i < MAX_TX_URBS; i++)
 703                 dev->tx_contexts[i].echo_index = MAX_TX_URBS;
 704 }
 705
 706 static int ems_usb_open(struct net_device *netdev)
 707 {
 708         struct ems_usb *dev = netdev_priv(netdev);
 709         int err;
 710
 711         err = ems_usb_write_mode(dev, SJA1000_MOD_RM);
 712         if (err)
 713                 return err;
 714
 715         /* common open */
 716         err = open_candev(netdev);
 717         if (err)
 718                 return err;
 719
 720         /* finally start device */
 721         err = ems_usb_start(dev);
 722         if (err) {
 723                 if (err == -ENODEV)
 724                         netif_device_detach(dev->netdev);
 725
 726                 netdev_warn(netdev, "couldn't start device: %d\n", err);
 727
 728                 close_candev(netdev);
 729
 730                 return err;
 731         }
 732
 733
 734         netif_start_queue(netdev);
 735
 736         return 0;
 737 }
 738
 739 static netdev_tx_t ems_usb_start_xmit(struct sk_buff *skb, struct net_device *netdev)
 740 {
 741         struct ems_usb *dev = netdev_priv(netdev);
 742         struct ems_tx_urb_context *context = NULL;
 743         struct net_device_stats *stats = &netdev->stats;
 744         struct can_frame *cf = (struct can_frame *)skb->data;
 745         struct ems_cpc_msg *msg;
 746         struct urb *urb;
 747         u8 *buf;
 748         int i, err;
 749         size_t size = CPC_HEADER_SIZE + CPC_MSG_HEADER_LEN
 750                         + sizeof(struct cpc_can_msg);
 751
 752         if (can_dropped_invalid_skb(netdev, skb))
 753                 return NETDEV_TX_OK;
 754
 755         /* create a URB, and a buffer for it, and copy the data to the URB */
 756         urb = usb_alloc_urb(0, GFP_ATOMIC);
 757         if (!urb)
 758                 goto nomem;
 759
 760         buf = usb_alloc_coherent(dev->udev, size, GFP_ATOMIC, &urb->transfer_dma);
 761         if (!buf) {
 762                 netdev_err(netdev, "No memory left for USB buffer\n");
 763                 usb_free_urb(urb);
 764                 goto nomem;
 765         }
 766
 767         msg = (struct ems_cpc_msg *)&buf[CPC_HEADER_SIZE];
 768
 769         msg->msg.can_msg.id = cpu_to_le32(cf->can_id & CAN_ERR_MASK);
 770         msg->msg.can_msg.length = cf->can_dlc;
 771
 772         if (cf->can_id & CAN_RTR_FLAG) {
 773                 msg->type = cf->can_id & CAN_EFF_FLAG ?
 774                         CPC_CMD_TYPE_EXT_RTR_FRAME : CPC_CMD_TYPE_RTR_FRAME;
 775
 776                 msg->length = CPC_CAN_MSG_MIN_SIZE;
 777         } else {
 778                 msg->type = cf->can_id & CAN_EFF_FLAG ?
 779                         CPC_CMD_TYPE_EXT_CAN_FRAME : CPC_CMD_TYPE_CAN_FRAME;
 780
 781                 for (i = 0; i < cf->can_dlc; i++)
 782                         msg->msg.can_msg.msg[i] = cf->data[i];
 783
 784                 msg->length = CPC_CAN_MSG_MIN_SIZE + cf->can_dlc;
 785         }
 786
 787         for (i = 0; i < MAX_TX_URBS; i++) {
 788                 if (dev->tx_contexts[i].echo_index == MAX_TX_URBS) {
 789                         context = &dev->tx_contexts[i];
 790                         break;
 791                 }
 792         }
 793
 794         /*
 795          * May never happen! When this happens we'd more URBs in flight as
 796          * allowed (MAX_TX_URBS).
 797          */
 798         if (!context) {
 799                 usb_free_coherent(dev->udev, size, buf, urb->transfer_dma);
 800                 usb_free_urb(urb);
 801
 802                 netdev_warn(netdev, "couldn't find free context\n");
 803
 804                 return NETDEV_TX_BUSY;
 805         }
 806
 807         context->dev = dev;
 808         context->echo_index = i;
 809         context->dlc = cf->can_dlc;
 810
 811         usb_fill_bulk_urb(urb, dev->udev, usb_sndbulkpipe(dev->udev, 2), buf,
 812                           size, ems_usb_write_bulk_callback, context);
 813         urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 814         usb_anchor_urb(urb, &dev->tx_submitted);
 815
 816         can_put_echo_skb(skb, netdev, context->echo_index);
 817
 818         atomic_inc(&dev->active_tx_urbs);
 819
 820         err = usb_submit_urb(urb, GFP_ATOMIC);
 821         if (unlikely(err)) {
 822                 can_free_echo_skb(netdev, context->echo_index);
 823
 824                 usb_unanchor_urb(urb);
 825                 usb_free_coherent(dev->udev, size, buf, urb->transfer_dma);
 826
 827                 atomic_dec(&dev->active_tx_urbs);
 828
 829                 if (err == -ENODEV) {
 830                         netif_device_detach(netdev);
 831                 } else {
 832                         netdev_warn(netdev, "failed tx_urb %d\n", err);
 833
 834                         stats->tx_dropped++;
 835                 }
 836         } else {
 837                 netif_trans_update(netdev);
 838
 839                 /* Slow down tx path */
 840                 if (atomic_read(&dev->active_tx_urbs) >= MAX_TX_URBS ||
 841                     dev->free_slots < CPC_TX_QUEUE_TRIGGER_LOW) {
 842                         netif_stop_queue(netdev);
 843                 }
 844         }
 845
 846         /*
 847          * Release our reference to this URB, the USB core will eventually free
 848          * it entirely.
 849          */
 850         usb_free_urb(urb);
 851
 852         return NETDEV_TX_OK;
 853
 854 nomem:
 855         dev_kfree_skb(skb);
 856         stats->tx_dropped++;
 857
 858         return NETDEV_TX_OK;
 859 }
 860
 861 static int ems_usb_close(struct net_device *netdev)
 862 {
 863         struct ems_usb *dev = netdev_priv(netdev);
 864
 865         /* Stop polling */
 866         unlink_all_urbs(dev);
 867
 868         netif_stop_queue(netdev);
 869
 870         /* Set CAN controller to reset mode */
 871         if (ems_usb_write_mode(dev, SJA1000_MOD_RM))
 872                 netdev_warn(netdev, "couldn't stop device");
 873
 874         close_candev(netdev);
 875
 876         return 0;
 877 }
 878
 879 static const struct net_device_ops ems_usb_netdev_ops = {
 880         .ndo_open = ems_usb_open,
 881         .ndo_stop = ems_usb_close,
 882         .ndo_start_xmit = ems_usb_start_xmit,
 883         .ndo_change_mtu = can_change_mtu,
 884 };
 885
 886 static const struct can_bittiming_const ems_usb_bittiming_const = {
 887         .name = "ems_usb",
 888         .tseg1_min = 1,
 889         .tseg1_max = 16,
 890         .tseg2_min = 1,
 891         .tseg2_max = 8,
 892         .sjw_max = 4,
 893         .brp_min = 1,
 894         .brp_max = 64,
 895         .brp_inc = 1,
 896 };
 897
 898 static int ems_usb_set_mode(struct net_device *netdev, enum can_mode mode)
 899 {
 900         struct ems_usb *dev = netdev_priv(netdev);
 901
 902         switch (mode) {
 903         case CAN_MODE_START:
 904                 if (ems_usb_write_mode(dev, SJA1000_MOD_NORMAL))
 905                         netdev_warn(netdev, "couldn't start device");
 906
 907                 if (netif_queue_stopped(netdev))
 908                         netif_wake_queue(netdev);
 909                 break;
 910
 911         default:
 912                 return -EOPNOTSUPP;
 913         }
 914
 915         return 0;
 916 }
 917
 918 static int ems_usb_set_bittiming(struct net_device *netdev)
 919 {
 920         struct ems_usb *dev = netdev_priv(netdev);
 921         struct can_bittiming *bt = &dev->can.bittiming;
 922         u8 btr0, btr1;
 923
 924         btr0 = ((bt->brp - 1) & 0x3f) | (((bt->sjw - 1) & 0x3) << 6);
 925         btr1 = ((bt->prop_seg + bt->phase_seg1 - 1) & 0xf) |
 926                 (((bt->phase_seg2 - 1) & 0x7) << 4);
 927         if (dev->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES)
 928                 btr1 |= 0x80;
 929
 930         netdev_info(netdev, "setting BTR0=0x%02x BTR1=0x%02x\n", btr0, btr1);
 931
 932         dev->active_params.msg.can_params.cc_params.sja1000.btr0 = btr0;
 933         dev->active_params.msg.can_params.cc_params.sja1000.btr1 = btr1;
 934
 935         return ems_usb_command_msg(dev, &dev->active_params);
 936 }
 937
 938 static void init_params_sja1000(struct ems_cpc_msg *msg)
 939 {
 940         struct cpc_sja1000_params *sja1000 =
 941                 &msg->msg.can_params.cc_params.sja1000;
 942
 943         msg->type = CPC_CMD_TYPE_CAN_PARAMS;
 944         msg->length = sizeof(struct cpc_can_params);
 945         msg->msgid = 0;
 946
 947         msg->msg.can_params.cc_type = CPC_CC_TYPE_SJA1000;
 948
 949         /* Acceptance filter open */
 950         sja1000->acc_code0 = 0x00;
 951         sja1000->acc_code1 = 0x00;
 952         sja1000->acc_code2 = 0x00;
 953         sja1000->acc_code3 = 0x00;
 954
 955         /* Acceptance filter open */
 956         sja1000->acc_mask0 = 0xFF;
 957         sja1000->acc_mask1 = 0xFF;
 958         sja1000->acc_mask2 = 0xFF;
 959         sja1000->acc_mask3 = 0xFF;
 960
 961         sja1000->btr0 = 0;
 962         sja1000->btr1 = 0;
 963
 964         sja1000->outp_contr = SJA1000_DEFAULT_OUTPUT_CONTROL;
 965         sja1000->mode = SJA1000_MOD_RM;
 966 }
 967
 968 /*
 969  * probe function for new CPC-USB devices
 970  */
 971 static int ems_usb_probe(struct usb_interface *intf,
 972                          const struct usb_device_id *id)
 973 {
 974         struct net_device *netdev;
 975         struct ems_usb *dev;
 976         int i, err = -ENOMEM;
 977
 978         netdev = alloc_candev(sizeof(struct ems_usb), MAX_TX_URBS);
 979         if (!netdev) {
 980                 dev_err(&intf->dev, "ems_usb: Couldn't alloc candev\n");
 981                 return -ENOMEM;
 982         }
 983
 984         dev = netdev_priv(netdev);
 985
 986         dev->udev = interface_to_usbdev(intf);
 987         dev->netdev = netdev;
 988
 989         dev->can.state = CAN_STATE_STOPPED;
 990         dev->can.clock.freq = EMS_USB_ARM7_CLOCK;
 991         dev->can.bittiming_const = &ems_usb_bittiming_const;
 992         dev->can.do_set_bittiming = ems_usb_set_bittiming;
 993         dev->can.do_set_mode = ems_usb_set_mode;
 994         dev->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES;
 995
 996         netdev->netdev_ops = &ems_usb_netdev_ops;
 997
 998         netdev->flags |= IFF_ECHO; /* we support local echo */
 999
1000         init_usb_anchor(&dev->rx_submitted);
1001
1002         init_usb_anchor(&dev->tx_submitted);
1003         atomic_set(&dev->active_tx_urbs, 0);
1004
1005         for (i = 0; i < MAX_TX_URBS; i++)
1006                 dev->tx_contexts[i].echo_index = MAX_TX_URBS;
1007
1008         dev->intr_urb = usb_alloc_urb(0, GFP_KERNEL);
1009         if (!dev->intr_urb)
1010                 goto cleanup_candev;
1011
1012         dev->intr_in_buffer = kzalloc(INTR_IN_BUFFER_SIZE, GFP_KERNEL);
1013         if (!dev->intr_in_buffer)
1014                 goto cleanup_intr_urb;
1015
1016         dev->tx_msg_buffer = kzalloc(CPC_HEADER_SIZE +
1017                                      sizeof(struct ems_cpc_msg), GFP_KERNEL);
1018         if (!dev->tx_msg_buffer)
1019                 goto cleanup_intr_in_buffer;
1020
1021         usb_set_intfdata(intf, dev);
1022
1023         SET_NETDEV_DEV(netdev, &intf->dev);
1024
1025         init_params_sja1000(&dev->active_params);
1026
1027         err = ems_usb_command_msg(dev, &dev->active_params);
1028         if (err) {
1029                 netdev_err(netdev, "couldn't initialize controller: %d\n", err);
1030                 goto cleanup_tx_msg_buffer;
1031         }
1032
1033         err = register_candev(netdev);
1034         if (err) {
1035                 netdev_err(netdev, "couldn't register CAN device: %d\n", err);
1036                 goto cleanup_tx_msg_buffer;
1037         }
1038
1039         return 0;
1040
1041 cleanup_tx_msg_buffer:
1042         kfree(dev->tx_msg_buffer);
1043
1044 cleanup_intr_in_buffer:
1045         kfree(dev->intr_in_buffer);
1046
1047 cleanup_intr_urb:
1048         usb_free_urb(dev->intr_urb);
1049
1050 cleanup_candev:
1051         free_candev(netdev);
1052
1053         return err;
1054 }
1055
1056 /*
1057  * called by the usb core when the device is removed from the system
1058  */
1059 static void ems_usb_disconnect(struct usb_interface *intf)
1060 {
1061         struct ems_usb *dev = usb_get_intfdata(intf);
1062
1063         usb_set_intfdata(intf, NULL);
1064
1065         if (dev) {
1066                 unregister_netdev(dev->netdev);
1067
1068                 unlink_all_urbs(dev);
1069
1070                 usb_free_urb(dev->intr_urb);
1071
1072                 kfree(dev->intr_in_buffer);
1073                 kfree(dev->tx_msg_buffer);
1074
1075                 free_candev(dev->netdev);
1076         }
1077 }
1078
1079 /* usb specific object needed to register this driver with the usb subsystem */
1080 static struct usb_driver ems_usb_driver = {
1081         .name = "ems_usb",
1082         .probe = ems_usb_probe,
1083         .disconnect = ems_usb_disconnect,
1084         .id_table = ems_usb_table,
1085 };
1086
1087 module_usb_driver(ems_usb_driver);