drivers/net/can/usb/ems_usb.c

   1 /*
   2  * CAN driver for EMS Dr. Thomas Wuensche CPC-USB/ARM7
   3  *
   4  * Copyright (C) 2004-2009 EMS Dr. Thomas Wuensche
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License as published
   8  * by the Free Software Foundation; version 2 of the License.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19 #include <linux/init.h>
  20 #include <linux/signal.h>
  21 #include <linux/slab.h>
  22 #include <linux/module.h>
  23 #include <linux/netdevice.h>
  24 #include <linux/usb.h>
  25
  26 #include <linux/can.h>
  27 #include <linux/can/dev.h>
  28 #include <linux/can/error.h>
  29
  30 MODULE_AUTHOR("Sebastian Haas <haas@ems-wuensche.com>");
  31 MODULE_DESCRIPTION("CAN driver for EMS Dr. Thomas Wuensche CAN/USB interfaces");
  32 MODULE_LICENSE("GPL v2");
  33
  34 /* Control-Values for CPC_Control() Command Subject Selection */
  35 #define CONTR_CAN_MESSAGE 0x04
  36 #define CONTR_CAN_STATE   0x0C
  37 #define CONTR_BUS_ERROR   0x1C
  38
  39 /* Control Command Actions */
  40 #define CONTR_CONT_OFF 0
  41 #define CONTR_CONT_ON  1
  42 #define CONTR_ONCE     2
  43
  44 /* Messages from CPC to PC */
  45 #define CPC_MSG_TYPE_CAN_FRAME       1  /* CAN data frame */
  46 #define CPC_MSG_TYPE_RTR_FRAME       8  /* CAN remote frame */
  47 #define CPC_MSG_TYPE_CAN_PARAMS      12 /* Actual CAN parameters */
  48 #define CPC_MSG_TYPE_CAN_STATE       14 /* CAN state message */
  49 #define CPC_MSG_TYPE_EXT_CAN_FRAME   16 /* Extended CAN data frame */
  50 #define CPC_MSG_TYPE_EXT_RTR_FRAME   17 /* Extended remote frame */
  51 #define CPC_MSG_TYPE_CONTROL         19 /* change interface behavior */
  52 #define CPC_MSG_TYPE_CONFIRM         20 /* command processed confirmation */
  53 #define CPC_MSG_TYPE_OVERRUN         21 /* overrun events */
  54 #define CPC_MSG_TYPE_CAN_FRAME_ERROR 23 /* detected bus errors */
  55 #define CPC_MSG_TYPE_ERR_COUNTER     25 /* RX/TX error counter */
  56
  57 /* Messages from the PC to the CPC interface  */
  58 #define CPC_CMD_TYPE_CAN_FRAME     1   /* CAN data frame */
  59 #define CPC_CMD_TYPE_CONTROL       3   /* control of interface behavior */
  60 #define CPC_CMD_TYPE_CAN_PARAMS    6   /* set CAN parameters */
  61 #define CPC_CMD_TYPE_RTR_FRAME     13  /* CAN remote frame */
  62 #define CPC_CMD_TYPE_CAN_STATE     14  /* CAN state message */
  63 #define CPC_CMD_TYPE_EXT_CAN_FRAME 15  /* Extended CAN data frame */
  64 #define CPC_CMD_TYPE_EXT_RTR_FRAME 16  /* Extended CAN remote frame */
  65 #define CPC_CMD_TYPE_CAN_EXIT      200 /* exit the CAN */
  66
  67 #define CPC_CMD_TYPE_INQ_ERR_COUNTER 25 /* request the CAN error counters */
  68 #define CPC_CMD_TYPE_CLEAR_MSG_QUEUE 8  /* clear CPC_MSG queue */
  69 #define CPC_CMD_TYPE_CLEAR_CMD_QUEUE 28 /* clear CPC_CMD queue */
  70
  71 #define CPC_CC_TYPE_SJA1000 2 /* Philips basic CAN controller */
  72
  73 #define CPC_CAN_ECODE_ERRFRAME 0x01 /* Ecode type */
  74
  75 /* Overrun types */
  76 #define CPC_OVR_EVENT_CAN       0x01
  77 #define CPC_OVR_EVENT_CANSTATE  0x02
  78 #define CPC_OVR_EVENT_BUSERROR  0x04
  79
  80 /*
  81  * If the CAN controller lost a message we indicate it with the highest bit
  82  * set in the count field.
  83  */
  84 #define CPC_OVR_HW 0x80
  85
  86 /* Size of the "struct ems_cpc_msg" without the union */
  87 #define CPC_MSG_HEADER_LEN   11
  88 #define CPC_CAN_MSG_MIN_SIZE 5
  89
  90 /* Define these values to match your devices */
  91 #define USB_CPCUSB_VENDOR_ID 0x12D6
  92
  93 #define USB_CPCUSB_ARM7_PRODUCT_ID 0x0444
  94
  95 /* Mode register NXP LPC2119/SJA1000 CAN Controller */
  96 #define SJA1000_MOD_NORMAL 0x00
  97 #define SJA1000_MOD_RM     0x01
  98
  99 /* ECC register NXP LPC2119/SJA1000 CAN Controller */
 100 #define SJA1000_ECC_SEG   0x1F
 101 #define SJA1000_ECC_DIR   0x20
 102 #define SJA1000_ECC_ERR   0x06
 103 #define SJA1000_ECC_BIT   0x00
 104 #define SJA1000_ECC_FORM  0x40
 105 #define SJA1000_ECC_STUFF 0x80
 106 #define SJA1000_ECC_MASK  0xc0
 107
 108 /* Status register content */
 109 #define SJA1000_SR_BS 0x80
 110 #define SJA1000_SR_ES 0x40
 111
 112 #define SJA1000_DEFAULT_OUTPUT_CONTROL 0xDA
 113
 114 /*
 115  * The device actually uses a 16MHz clock to generate the CAN clock
 116  * but it expects SJA1000 bit settings based on 8MHz (is internally
 117  * converted).
 118  */
 119 #define EMS_USB_ARM7_CLOCK 8000000
 120
 121 /*
 122  * CAN-Message representation in a CPC_MSG. Message object type is
 123  * CPC_MSG_TYPE_CAN_FRAME or CPC_MSG_TYPE_RTR_FRAME or
 124  * CPC_MSG_TYPE_EXT_CAN_FRAME or CPC_MSG_TYPE_EXT_RTR_FRAME.
 125  */
 126 struct cpc_can_msg {
 127         u32 id;
 128         u8 length;
 129         u8 msg[8];
 130 };
 131
 132 /* Representation of the CAN parameters for the SJA1000 controller */
 133 struct cpc_sja1000_params {
 134         u8 mode;
 135         u8 acc_code0;
 136         u8 acc_code1;
 137         u8 acc_code2;
 138         u8 acc_code3;
 139         u8 acc_mask0;
 140         u8 acc_mask1;
 141         u8 acc_mask2;
 142         u8 acc_mask3;
 143         u8 btr0;
 144         u8 btr1;
 145         u8 outp_contr;
 146 };
 147
 148 /* CAN params message representation */
 149 struct cpc_can_params {
 150         u8 cc_type;
 151
 152         /* Will support M16C CAN controller in the future */
 153         union {
 154                 struct cpc_sja1000_params sja1000;
 155         } cc_params;
 156 };
 157
 158 /* Structure for confirmed message handling */
 159 struct cpc_confirm {
 160         u8 error; /* error code */
 161 };
 162
 163 /* Structure for overrun conditions */
 164 struct cpc_overrun {
 165         u8 event;
 166         u8 count;
 167 };
 168
 169 /* SJA1000 CAN errors (compatible to NXP LPC2119) */
 170 struct cpc_sja1000_can_error {
 171         u8 ecc;
 172         u8 rxerr;
 173         u8 txerr;
 174 };
 175
 176 /* structure for CAN error conditions */
 177 struct cpc_can_error {
 178         u8 ecode;
 179
 180         struct {
 181                 u8 cc_type;
 182
 183                 /* Other controllers may also provide error code capture regs */
 184                 union {
 185                         struct cpc_sja1000_can_error sja1000;
 186                 } regs;
 187         } cc;
 188 };
 189
 190 /*
 191  * Structure containing RX/TX error counter. This structure is used to request
 192  * the values of the CAN controllers TX and RX error counter.
 193  */
 194 struct cpc_can_err_counter {
 195         u8 rx;
 196         u8 tx;
 197 };
 198
 199 /* Main message type used between library and application */
 200 struct __packed ems_cpc_msg {
 201         u8 type;        /* type of message */
 202         u8 length;      /* length of data within union 'msg' */
 203         u8 msgid;       /* confirmation handle */
 204         u32 ts_sec;     /* timestamp in seconds */
 205         u32 ts_nsec;    /* timestamp in nano seconds */
 206
 207         union {
 208                 u8 generic[64];
 209                 struct cpc_can_msg can_msg;
 210                 struct cpc_can_params can_params;
 211                 struct cpc_confirm confirmation;
 212                 struct cpc_overrun overrun;
 213                 struct cpc_can_error error;
 214                 struct cpc_can_err_counter err_counter;
 215                 u8 can_state;
 216         } msg;
 217 };
 218
 219 /*
 220  * Table of devices that work with this driver
 221  * NOTE: This driver supports only CPC-USB/ARM7 (LPC2119) yet.
 222  */
 223 static struct usb_device_id ems_usb_table[] = {
 224         {USB_DEVICE(USB_CPCUSB_VENDOR_ID, USB_CPCUSB_ARM7_PRODUCT_ID)},
 225         {} /* Terminating entry */
 226 };
 227
 228 MODULE_DEVICE_TABLE(usb, ems_usb_table);
 229
 230 #define RX_BUFFER_SIZE      64
 231 #define CPC_HEADER_SIZE     4
 232 #define INTR_IN_BUFFER_SIZE 4
 233
 234 #define MAX_RX_URBS 10
 235 #define MAX_TX_URBS 10
 236
 237 struct ems_usb;
 238
 239 struct ems_tx_urb_context {
 240         struct ems_usb *dev;
 241
 242         u32 echo_index;
 243         u8 dlc;
 244 };
 245
 246 struct ems_usb {
 247         struct can_priv can; /* must be the first member */
 248         int open_time;
 249
 250         struct sk_buff *echo_skb[MAX_TX_URBS];
 251
 252         struct usb_device *udev;
 253         struct net_device *netdev;
 254
 255         atomic_t active_tx_urbs;
 256         struct usb_anchor tx_submitted;
 257         struct ems_tx_urb_context tx_contexts[MAX_TX_URBS];
 258
 259         struct usb_anchor rx_submitted;
 260
 261         struct urb *intr_urb;
 262
 263         u8 *tx_msg_buffer;
 264
 265         u8 *intr_in_buffer;
 266         unsigned int free_slots; /* remember number of available slots */
 267
 268         struct ems_cpc_msg active_params; /* active controller parameters */
 269 };
 270
 271 static void ems_usb_read_interrupt_callback(struct urb *urb)
 272 {
 273         struct ems_usb *dev = urb->context;
 274         struct net_device *netdev = dev->netdev;
 275         int err;
 276
 277         if (!netif_device_present(netdev))
 278                 return;
 279
 280         switch (urb->status) {
 281         case 0:
 282                 dev->free_slots = dev->intr_in_buffer[1];
 283                 break;
 284
 285         case -ECONNRESET: /* unlink */
 286         case -ENOENT:
 287         case -ESHUTDOWN:
 288                 return;
 289
 290         default:
 291                 dev_info(netdev->dev.parent, "Rx interrupt aborted %d\n",
 292                          urb->status);
 293                 break;
 294         }
 295
 296         err = usb_submit_urb(urb, GFP_ATOMIC);
 297
 298         if (err == -ENODEV)
 299                 netif_device_detach(netdev);
 300         else if (err)
 301                 dev_err(netdev->dev.parent,
 302                         "failed resubmitting intr urb: %d\n", err);
 303 }
 304
 305 static void ems_usb_rx_can_msg(struct ems_usb *dev, struct ems_cpc_msg *msg)
 306 {
 307         struct can_frame *cf;
 308         struct sk_buff *skb;
 309         int i;
 310         struct net_device_stats *stats = &dev->netdev->stats;
 311
 312         skb = alloc_can_skb(dev->netdev, &cf);
 313         if (skb == NULL)
 314                 return;
 315
 316         cf->can_id = le32_to_cpu(msg->msg.can_msg.id);
 317         cf->can_dlc = get_can_dlc(msg->msg.can_msg.length & 0xF);
 318
 319         if (msg->type == CPC_MSG_TYPE_EXT_CAN_FRAME ||
 320             msg->type == CPC_MSG_TYPE_EXT_RTR_FRAME)
 321                 cf->can_id |= CAN_EFF_FLAG;
 322
 323         if (msg->type == CPC_MSG_TYPE_RTR_FRAME ||
 324             msg->type == CPC_MSG_TYPE_EXT_RTR_FRAME) {
 325                 cf->can_id |= CAN_RTR_FLAG;
 326         } else {
 327                 for (i = 0; i < cf->can_dlc; i++)
 328                         cf->data[i] = msg->msg.can_msg.msg[i];
 329         }
 330
 331         netif_rx(skb);
 332
 333         stats->rx_packets++;
 334         stats->rx_bytes += cf->can_dlc;
 335 }
 336
 337 static void ems_usb_rx_err(struct ems_usb *dev, struct ems_cpc_msg *msg)
 338 {
 339         struct can_frame *cf;
 340         struct sk_buff *skb;
 341         struct net_device_stats *stats = &dev->netdev->stats;
 342
 343         skb = alloc_can_err_skb(dev->netdev, &cf);
 344         if (skb == NULL)
 345                 return;
 346
 347         if (msg->type == CPC_MSG_TYPE_CAN_STATE) {
 348                 u8 state = msg->msg.can_state;
 349
 350                 if (state & SJA1000_SR_BS) {
 351                         dev->can.state = CAN_STATE_BUS_OFF;
 352                         cf->can_id |= CAN_ERR_BUSOFF;
 353
 354                         can_bus_off(dev->netdev);
 355                 } else if (state & SJA1000_SR_ES) {
 356                         dev->can.state = CAN_STATE_ERROR_WARNING;
 357                         dev->can.can_stats.error_warning++;
 358                 } else {
 359                         dev->can.state = CAN_STATE_ERROR_ACTIVE;
 360                         dev->can.can_stats.error_passive++;
 361                 }
 362         } else if (msg->type == CPC_MSG_TYPE_CAN_FRAME_ERROR) {
 363                 u8 ecc = msg->msg.error.cc.regs.sja1000.ecc;
 364                 u8 txerr = msg->msg.error.cc.regs.sja1000.txerr;
 365                 u8 rxerr = msg->msg.error.cc.regs.sja1000.rxerr;
 366
 367                 /* bus error interrupt */
 368                 dev->can.can_stats.bus_error++;
 369                 stats->rx_errors++;
 370
 371                 cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
 372
 373                 switch (ecc & SJA1000_ECC_MASK) {
 374                 case SJA1000_ECC_BIT:
 375                         cf->data[2] |= CAN_ERR_PROT_BIT;
 376                         break;
 377                 case SJA1000_ECC_FORM:
 378                         cf->data[2] |= CAN_ERR_PROT_FORM;
 379                         break;
 380                 case SJA1000_ECC_STUFF:
 381                         cf->data[2] |= CAN_ERR_PROT_STUFF;
 382                         break;
 383                 default:
 384                         cf->data[2] |= CAN_ERR_PROT_UNSPEC;
 385                         cf->data[3] = ecc & SJA1000_ECC_SEG;
 386                         break;
 387                 }
 388
 389                 /* Error occurred during transmission? */
 390                 if ((ecc & SJA1000_ECC_DIR) == 0)
 391                         cf->data[2] |= CAN_ERR_PROT_TX;
 392
 393                 if (dev->can.state == CAN_STATE_ERROR_WARNING ||
 394                     dev->can.state == CAN_STATE_ERROR_PASSIVE) {
 395                         cf->data[1] = (txerr > rxerr) ?
 396                             CAN_ERR_CRTL_TX_PASSIVE : CAN_ERR_CRTL_RX_PASSIVE;
 397                 }
 398         } else if (msg->type == CPC_MSG_TYPE_OVERRUN) {
 399                 cf->can_id |= CAN_ERR_CRTL;
 400                 cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
 401
 402                 stats->rx_over_errors++;
 403                 stats->rx_errors++;
 404         }
 405
 406         netif_rx(skb);
 407
 408         stats->rx_packets++;
 409         stats->rx_bytes += cf->can_dlc;
 410 }
 411
 412 /*
 413  * callback for bulk IN urb
 414  */
 415 static void ems_usb_read_bulk_callback(struct urb *urb)
 416 {
 417         struct ems_usb *dev = urb->context;
 418         struct net_device *netdev;
 419         int retval;
 420
 421         netdev = dev->netdev;
 422
 423         if (!netif_device_present(netdev))
 424                 return;
 425
 426         switch (urb->status) {
 427         case 0: /* success */
 428                 break;
 429
 430         case -ENOENT:
 431                 return;
 432
 433         default:
 434                 dev_info(netdev->dev.parent, "Rx URB aborted (%d)\n",
 435                          urb->status);
 436                 goto resubmit_urb;
 437         }
 438
 439         if (urb->actual_length > CPC_HEADER_SIZE) {
 440                 struct ems_cpc_msg *msg;
 441                 u8 *ibuf = urb->transfer_buffer;
 442                 u8 msg_count, again, start;
 443
 444                 msg_count = ibuf[0] & ~0x80;
 445                 again = ibuf[0] & 0x80;
 446
 447                 start = CPC_HEADER_SIZE;
 448
 449                 while (msg_count) {
 450                         msg = (struct ems_cpc_msg *)&ibuf[start];
 451
 452                         switch (msg->type) {
 453                         case CPC_MSG_TYPE_CAN_STATE:
 454                                 /* Process CAN state changes */
 455                                 ems_usb_rx_err(dev, msg);
 456                                 break;
 457
 458                         case CPC_MSG_TYPE_CAN_FRAME:
 459                         case CPC_MSG_TYPE_EXT_CAN_FRAME:
 460                         case CPC_MSG_TYPE_RTR_FRAME:
 461                         case CPC_MSG_TYPE_EXT_RTR_FRAME:
 462                                 ems_usb_rx_can_msg(dev, msg);
 463                                 break;
 464
 465                         case CPC_MSG_TYPE_CAN_FRAME_ERROR:
 466                                 /* Process errorframe */
 467                                 ems_usb_rx_err(dev, msg);
 468                                 break;
 469
 470                         case CPC_MSG_TYPE_OVERRUN:
 471                                 /* Message lost while receiving */
 472                                 ems_usb_rx_err(dev, msg);
 473                                 break;
 474                         }
 475
 476                         start += CPC_MSG_HEADER_LEN + msg->length;
 477                         msg_count--;
 478
 479                         if (start > urb->transfer_buffer_length) {
 480                                 dev_err(netdev->dev.parent, "format error\n");
 481                                 break;
 482                         }
 483                 }
 484         }
 485
 486 resubmit_urb:
 487         usb_fill_bulk_urb(urb, dev->udev, usb_rcvbulkpipe(dev->udev, 2),
 488                           urb->transfer_buffer, RX_BUFFER_SIZE,
 489                           ems_usb_read_bulk_callback, dev);
 490
 491         retval = usb_submit_urb(urb, GFP_ATOMIC);
 492
 493         if (retval == -ENODEV)
 494                 netif_device_detach(netdev);
 495         else if (retval)
 496                 dev_err(netdev->dev.parent,
 497                         "failed resubmitting read bulk urb: %d\n", retval);
 498 }
 499
 500 /*
 501  * callback for bulk IN urb
 502  */
 503 static void ems_usb_write_bulk_callback(struct urb *urb)
 504 {
 505         struct ems_tx_urb_context *context = urb->context;
 506         struct ems_usb *dev;
 507         struct net_device *netdev;
 508
 509         BUG_ON(!context);
 510
 511         dev = context->dev;
 512         netdev = dev->netdev;
 513
 514         /* free up our allocated buffer */
 515         usb_free_coherent(urb->dev, urb->transfer_buffer_length,
 516                           urb->transfer_buffer, urb->transfer_dma);
 517
 518         atomic_dec(&dev->active_tx_urbs);
 519
 520         if (!netif_device_present(netdev))
 521                 return;
 522
 523         if (urb->status)
 524                 dev_info(netdev->dev.parent, "Tx URB aborted (%d)\n",
 525                          urb->status);
 526
 527         netdev->trans_start = jiffies;
 528
 529         /* transmission complete interrupt */
 530         netdev->stats.tx_packets++;
 531         netdev->stats.tx_bytes += context->dlc;
 532
 533         can_get_echo_skb(netdev, context->echo_index);
 534
 535         /* Release context */
 536         context->echo_index = MAX_TX_URBS;
 537
 538         if (netif_queue_stopped(netdev))
 539                 netif_wake_queue(netdev);
 540 }
 541
 542 /*
 543  * Send the given CPC command synchronously
 544  */
 545 static int ems_usb_command_msg(struct ems_usb *dev, struct ems_cpc_msg *msg)
 546 {
 547         int actual_length;
 548
 549         /* Copy payload */
 550         memcpy(&dev->tx_msg_buffer[CPC_HEADER_SIZE], msg,
 551                msg->length + CPC_MSG_HEADER_LEN);
 552
 553         /* Clear header */
 554         memset(&dev->tx_msg_buffer[0], 0, CPC_HEADER_SIZE);
 555
 556         return usb_bulk_msg(dev->udev, usb_sndbulkpipe(dev->udev, 2),
 557                             &dev->tx_msg_buffer[0],
 558                             msg->length + CPC_MSG_HEADER_LEN + CPC_HEADER_SIZE,
 559                             &actual_length, 1000);
 560 }
 561
 562 /*
 563  * Change CAN controllers' mode register
 564  */
 565 static int ems_usb_write_mode(struct ems_usb *dev, u8 mode)
 566 {
 567         dev->active_params.msg.can_params.cc_params.sja1000.mode = mode;
 568
 569         return ems_usb_command_msg(dev, &dev->active_params);
 570 }
 571
 572 /*
 573  * Send a CPC_Control command to change behaviour when interface receives a CAN
 574  * message, bus error or CAN state changed notifications.
 575  */
 576 static int ems_usb_control_cmd(struct ems_usb *dev, u8 val)
 577 {
 578         struct ems_cpc_msg cmd;
 579
 580         cmd.type = CPC_CMD_TYPE_CONTROL;
 581         cmd.length = CPC_MSG_HEADER_LEN + 1;
 582
 583         cmd.msgid = 0;
 584
 585         cmd.msg.generic[0] = val;
 586
 587         return ems_usb_command_msg(dev, &cmd);
 588 }
 589
 590 /*
 591  * Start interface
 592  */
 593 static int ems_usb_start(struct ems_usb *dev)
 594 {
 595         struct net_device *netdev = dev->netdev;
 596         int err, i;
 597
 598         dev->intr_in_buffer[0] = 0;
 599         dev->free_slots = 15; /* initial size */
 600
 601         for (i = 0; i < MAX_RX_URBS; i++) {
 602                 struct urb *urb = NULL;
 603                 u8 *buf = NULL;
 604
 605                 /* create a URB, and a buffer for it */
 606                 urb = usb_alloc_urb(0, GFP_KERNEL);
 607                 if (!urb) {
 608                         dev_err(netdev->dev.parent,
 609                                 "No memory left for URBs\n");
 610                         return -ENOMEM;
 611                 }
 612
 613                 buf = usb_alloc_coherent(dev->udev, RX_BUFFER_SIZE, GFP_KERNEL,
 614                                          &urb->transfer_dma);
 615                 if (!buf) {
 616                         dev_err(netdev->dev.parent,
 617                                 "No memory left for USB buffer\n");
 618                         usb_free_urb(urb);
 619                         return -ENOMEM;
 620                 }
 621
 622                 usb_fill_bulk_urb(urb, dev->udev, usb_rcvbulkpipe(dev->udev, 2),
 623                                   buf, RX_BUFFER_SIZE,
 624                                   ems_usb_read_bulk_callback, dev);
 625                 urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 626                 usb_anchor_urb(urb, &dev->rx_submitted);
 627
 628                 err = usb_submit_urb(urb, GFP_KERNEL);
 629                 if (err) {
 630                         if (err == -ENODEV)
 631                                 netif_device_detach(dev->netdev);
 632
 633                         usb_unanchor_urb(urb);
 634                         usb_free_coherent(dev->udev, RX_BUFFER_SIZE, buf,
 635                                           urb->transfer_dma);
 636                         break;
 637                 }
 638
 639                 /* Drop reference, USB core will take care of freeing it */
 640                 usb_free_urb(urb);
 641         }
 642
 643         /* Did we submit any URBs */
 644         if (i == 0) {
 645                 dev_warn(netdev->dev.parent, "couldn't setup read URBs\n");
 646                 return err;
 647         }
 648
 649         /* Warn if we've couldn't transmit all the URBs */
 650         if (i < MAX_RX_URBS)
 651                 dev_warn(netdev->dev.parent, "rx performance may be slow\n");
 652
 653         /* Setup and start interrupt URB */
 654         usb_fill_int_urb(dev->intr_urb, dev->udev,
 655                          usb_rcvintpipe(dev->udev, 1),
 656                          dev->intr_in_buffer,
 657                          INTR_IN_BUFFER_SIZE,
 658                          ems_usb_read_interrupt_callback, dev, 1);
 659
 660         err = usb_submit_urb(dev->intr_urb, GFP_KERNEL);
 661         if (err) {
 662                 if (err == -ENODEV)
 663                         netif_device_detach(dev->netdev);
 664
 665                 dev_warn(netdev->dev.parent, "intr URB submit failed: %d\n",
 666                          err);
 667
 668                 return err;
 669         }
 670
 671         /* CPC-USB will transfer received message to host */
 672         err = ems_usb_control_cmd(dev, CONTR_CAN_MESSAGE | CONTR_CONT_ON);
 673         if (err)
 674                 goto failed;
 675
 676         /* CPC-USB will transfer CAN state changes to host */
 677         err = ems_usb_control_cmd(dev, CONTR_CAN_STATE | CONTR_CONT_ON);
 678         if (err)
 679                 goto failed;
 680
 681         /* CPC-USB will transfer bus errors to host */
 682         err = ems_usb_control_cmd(dev, CONTR_BUS_ERROR | CONTR_CONT_ON);
 683         if (err)
 684                 goto failed;
 685
 686         err = ems_usb_write_mode(dev, SJA1000_MOD_NORMAL);
 687         if (err)
 688                 goto failed;
 689
 690         dev->can.state = CAN_STATE_ERROR_ACTIVE;
 691
 692         return 0;
 693
 694 failed:
 695         if (err == -ENODEV)
 696                 netif_device_detach(dev->netdev);
 697
 698         dev_warn(netdev->dev.parent, "couldn't submit control: %d\n", err);
 699
 700         return err;
 701 }
 702
 703 static void unlink_all_urbs(struct ems_usb *dev)
 704 {
 705         int i;
 706
 707         usb_unlink_urb(dev->intr_urb);
 708
 709         usb_kill_anchored_urbs(&dev->rx_submitted);
 710
 711         usb_kill_anchored_urbs(&dev->tx_submitted);
 712         atomic_set(&dev->active_tx_urbs, 0);
 713
 714         for (i = 0; i < MAX_TX_URBS; i++)
 715                 dev->tx_contexts[i].echo_index = MAX_TX_URBS;
 716 }
 717
 718 static int ems_usb_open(struct net_device *netdev)
 719 {
 720         struct ems_usb *dev = netdev_priv(netdev);
 721         int err;
 722
 723         err = ems_usb_write_mode(dev, SJA1000_MOD_RM);
 724         if (err)
 725                 return err;
 726
 727         /* common open */
 728         err = open_candev(netdev);
 729         if (err)
 730                 return err;
 731
 732         /* finally start device */
 733         err = ems_usb_start(dev);
 734         if (err) {
 735                 if (err == -ENODEV)
 736                         netif_device_detach(dev->netdev);
 737
 738                 dev_warn(netdev->dev.parent, "couldn't start device: %d\n",
 739                          err);
 740
 741                 close_candev(netdev);
 742
 743                 return err;
 744         }
 745
 746         dev->open_time = jiffies;
 747
 748         netif_start_queue(netdev);
 749
 750         return 0;
 751 }
 752
 753 static netdev_tx_t ems_usb_start_xmit(struct sk_buff *skb, struct net_device *netdev)
 754 {
 755         struct ems_usb *dev = netdev_priv(netdev);
 756         struct ems_tx_urb_context *context = NULL;
 757         struct net_device_stats *stats = &netdev->stats;
 758         struct can_frame *cf = (struct can_frame *)skb->data;
 759         struct ems_cpc_msg *msg;
 760         struct urb *urb;
 761         u8 *buf;
 762         int i, err;
 763         size_t size = CPC_HEADER_SIZE + CPC_MSG_HEADER_LEN
 764                         + sizeof(struct cpc_can_msg);
 765
 766         if (can_dropped_invalid_skb(netdev, skb))
 767                 return NETDEV_TX_OK;
 768
 769         /* create a URB, and a buffer for it, and copy the data to the URB */
 770         urb = usb_alloc_urb(0, GFP_ATOMIC);
 771         if (!urb) {
 772                 dev_err(netdev->dev.parent, "No memory left for URBs\n");
 773                 goto nomem;
 774         }
 775
 776         buf = usb_alloc_coherent(dev->udev, size, GFP_ATOMIC, &urb->transfer_dma);
 777         if (!buf) {
 778                 dev_err(netdev->dev.parent, "No memory left for USB buffer\n");
 779                 usb_free_urb(urb);
 780                 goto nomem;
 781         }
 782
 783         msg = (struct ems_cpc_msg *)&buf[CPC_HEADER_SIZE];
 784
 785         msg->msg.can_msg.id = cf->can_id & CAN_ERR_MASK;
 786         msg->msg.can_msg.length = cf->can_dlc;
 787
 788         if (cf->can_id & CAN_RTR_FLAG) {
 789                 msg->type = cf->can_id & CAN_EFF_FLAG ?
 790                         CPC_CMD_TYPE_EXT_RTR_FRAME : CPC_CMD_TYPE_RTR_FRAME;
 791
 792                 msg->length = CPC_CAN_MSG_MIN_SIZE;
 793         } else {
 794                 msg->type = cf->can_id & CAN_EFF_FLAG ?
 795                         CPC_CMD_TYPE_EXT_CAN_FRAME : CPC_CMD_TYPE_CAN_FRAME;
 796
 797                 for (i = 0; i < cf->can_dlc; i++)
 798                         msg->msg.can_msg.msg[i] = cf->data[i];
 799
 800                 msg->length = CPC_CAN_MSG_MIN_SIZE + cf->can_dlc;
 801         }
 802
 803         /* Respect byte order */
 804         msg->msg.can_msg.id = cpu_to_le32(msg->msg.can_msg.id);
 805
 806         for (i = 0; i < MAX_TX_URBS; i++) {
 807                 if (dev->tx_contexts[i].echo_index == MAX_TX_URBS) {
 808                         context = &dev->tx_contexts[i];
 809                         break;
 810                 }
 811         }
 812
 813         /*
 814          * May never happen! When this happens we'd more URBs in flight as
 815          * allowed (MAX_TX_URBS).
 816          */
 817         if (!context) {
 818                 usb_unanchor_urb(urb);
 819                 usb_free_coherent(dev->udev, size, buf, urb->transfer_dma);
 820
 821                 dev_warn(netdev->dev.parent, "couldn't find free context\n");
 822
 823                 return NETDEV_TX_BUSY;
 824         }
 825
 826         context->dev = dev;
 827         context->echo_index = i;
 828         context->dlc = cf->can_dlc;
 829
 830         usb_fill_bulk_urb(urb, dev->udev, usb_sndbulkpipe(dev->udev, 2), buf,
 831                           size, ems_usb_write_bulk_callback, context);
 832         urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 833         usb_anchor_urb(urb, &dev->tx_submitted);
 834
 835         can_put_echo_skb(skb, netdev, context->echo_index);
 836
 837         atomic_inc(&dev->active_tx_urbs);
 838
 839         err = usb_submit_urb(urb, GFP_ATOMIC);
 840         if (unlikely(err)) {
 841                 can_free_echo_skb(netdev, context->echo_index);
 842
 843                 usb_unanchor_urb(urb);
 844                 usb_free_coherent(dev->udev, size, buf, urb->transfer_dma);
 845                 dev_kfree_skb(skb);
 846
 847                 atomic_dec(&dev->active_tx_urbs);
 848
 849                 if (err == -ENODEV) {
 850                         netif_device_detach(netdev);
 851                 } else {
 852                         dev_warn(netdev->dev.parent, "failed tx_urb %d\n", err);
 853
 854                         stats->tx_dropped++;
 855                 }
 856         } else {
 857                 netdev->trans_start = jiffies;
 858
 859                 /* Slow down tx path */
 860                 if (atomic_read(&dev->active_tx_urbs) >= MAX_TX_URBS ||
 861                     dev->free_slots < 5) {
 862                         netif_stop_queue(netdev);
 863                 }
 864         }
 865
 866         /*
 867          * Release our reference to this URB, the USB core will eventually free
 868          * it entirely.
 869          */
 870         usb_free_urb(urb);
 871
 872         return NETDEV_TX_OK;
 873
 874 nomem:
 875         dev_kfree_skb(skb);
 876         stats->tx_dropped++;
 877
 878         return NETDEV_TX_OK;
 879 }
 880
 881 static int ems_usb_close(struct net_device *netdev)
 882 {
 883         struct ems_usb *dev = netdev_priv(netdev);
 884
 885         /* Stop polling */
 886         unlink_all_urbs(dev);
 887
 888         netif_stop_queue(netdev);
 889
 890         /* Set CAN controller to reset mode */
 891         if (ems_usb_write_mode(dev, SJA1000_MOD_RM))
 892                 dev_warn(netdev->dev.parent, "couldn't stop device");
 893
 894         close_candev(netdev);
 895
 896         dev->open_time = 0;
 897
 898         return 0;
 899 }
 900
 901 static const struct net_device_ops ems_usb_netdev_ops = {
 902         .ndo_open = ems_usb_open,
 903         .ndo_stop = ems_usb_close,
 904         .ndo_start_xmit = ems_usb_start_xmit,
 905 };
 906
 907 static struct can_bittiming_const ems_usb_bittiming_const = {
 908         .name = "ems_usb",
 909         .tseg1_min = 1,
 910         .tseg1_max = 16,
 911         .tseg2_min = 1,
 912         .tseg2_max = 8,
 913         .sjw_max = 4,
 914         .brp_min = 1,
 915         .brp_max = 64,
 916         .brp_inc = 1,
 917 };
 918
 919 static int ems_usb_set_mode(struct net_device *netdev, enum can_mode mode)
 920 {
 921         struct ems_usb *dev = netdev_priv(netdev);
 922
 923         if (!dev->open_time)
 924                 return -EINVAL;
 925
 926         switch (mode) {
 927         case CAN_MODE_START:
 928                 if (ems_usb_write_mode(dev, SJA1000_MOD_NORMAL))
 929                         dev_warn(netdev->dev.parent, "couldn't start device");
 930
 931                 if (netif_queue_stopped(netdev))
 932                         netif_wake_queue(netdev);
 933                 break;
 934
 935         default:
 936                 return -EOPNOTSUPP;
 937         }
 938
 939         return 0;
 940 }
 941
 942 static int ems_usb_set_bittiming(struct net_device *netdev)
 943 {
 944         struct ems_usb *dev = netdev_priv(netdev);
 945         struct can_bittiming *bt = &dev->can.bittiming;
 946         u8 btr0, btr1;
 947
 948         btr0 = ((bt->brp - 1) & 0x3f) | (((bt->sjw - 1) & 0x3) << 6);
 949         btr1 = ((bt->prop_seg + bt->phase_seg1 - 1) & 0xf) |
 950                 (((bt->phase_seg2 - 1) & 0x7) << 4);
 951         if (dev->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES)
 952                 btr1 |= 0x80;
 953
 954         dev_info(netdev->dev.parent, "setting BTR0=0x%02x BTR1=0x%02x\n",
 955                  btr0, btr1);
 956
 957         dev->active_params.msg.can_params.cc_params.sja1000.btr0 = btr0;
 958         dev->active_params.msg.can_params.cc_params.sja1000.btr1 = btr1;
 959
 960         return ems_usb_command_msg(dev, &dev->active_params);
 961 }
 962
 963 static void init_params_sja1000(struct ems_cpc_msg *msg)
 964 {
 965         struct cpc_sja1000_params *sja1000 =
 966                 &msg->msg.can_params.cc_params.sja1000;
 967
 968         msg->type = CPC_CMD_TYPE_CAN_PARAMS;
 969         msg->length = sizeof(struct cpc_can_params);
 970         msg->msgid = 0;
 971
 972         msg->msg.can_params.cc_type = CPC_CC_TYPE_SJA1000;
 973
 974         /* Acceptance filter open */
 975         sja1000->acc_code0 = 0x00;
 976         sja1000->acc_code1 = 0x00;
 977         sja1000->acc_code2 = 0x00;
 978         sja1000->acc_code3 = 0x00;
 979
 980         /* Acceptance filter open */
 981         sja1000->acc_mask0 = 0xFF;
 982         sja1000->acc_mask1 = 0xFF;
 983         sja1000->acc_mask2 = 0xFF;
 984         sja1000->acc_mask3 = 0xFF;
 985
 986         sja1000->btr0 = 0;
 987         sja1000->btr1 = 0;
 988
 989         sja1000->outp_contr = SJA1000_DEFAULT_OUTPUT_CONTROL;
 990         sja1000->mode = SJA1000_MOD_RM;
 991 }
 992
 993 /*
 994  * probe function for new CPC-USB devices
 995  */
 996 static int ems_usb_probe(struct usb_interface *intf,
 997                          const struct usb_device_id *id)
 998 {
 999         struct net_device *netdev;
1000         struct ems_usb *dev;
1001         int i, err = -ENOMEM;
1002
1003         netdev = alloc_candev(sizeof(struct ems_usb), MAX_TX_URBS);
1004         if (!netdev) {
1005                 dev_err(&intf->dev, "ems_usb: Couldn't alloc candev\n");
1006                 return -ENOMEM;
1007         }
1008
1009         dev = netdev_priv(netdev);
1010
1011         dev->udev = interface_to_usbdev(intf);
1012         dev->netdev = netdev;
1013
1014         dev->can.state = CAN_STATE_STOPPED;
1015         dev->can.clock.freq = EMS_USB_ARM7_CLOCK;
1016         dev->can.bittiming_const = &ems_usb_bittiming_const;
1017         dev->can.do_set_bittiming = ems_usb_set_bittiming;
1018         dev->can.do_set_mode = ems_usb_set_mode;
1019         dev->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES;
1020
1021         netdev->netdev_ops = &ems_usb_netdev_ops;
1022
1023         netdev->flags |= IFF_ECHO; /* we support local echo */
1024
1025         init_usb_anchor(&dev->rx_submitted);
1026
1027         init_usb_anchor(&dev->tx_submitted);
1028         atomic_set(&dev->active_tx_urbs, 0);
1029
1030         for (i = 0; i < MAX_TX_URBS; i++)
1031                 dev->tx_contexts[i].echo_index = MAX_TX_URBS;
1032
1033         dev->intr_urb = usb_alloc_urb(0, GFP_KERNEL);
1034         if (!dev->intr_urb) {
1035                 dev_err(&intf->dev, "Couldn't alloc intr URB\n");
1036                 goto cleanup_candev;
1037         }
1038
1039         dev->intr_in_buffer = kzalloc(INTR_IN_BUFFER_SIZE, GFP_KERNEL);
1040         if (!dev->intr_in_buffer) {
1041                 dev_err(&intf->dev, "Couldn't alloc Intr buffer\n");
1042                 goto cleanup_intr_urb;
1043         }
1044
1045         dev->tx_msg_buffer = kzalloc(CPC_HEADER_SIZE +
1046                                      sizeof(struct ems_cpc_msg), GFP_KERNEL);
1047         if (!dev->tx_msg_buffer) {
1048                 dev_err(&intf->dev, "Couldn't alloc Tx buffer\n");
1049                 goto cleanup_intr_in_buffer;
1050         }
1051
1052         usb_set_intfdata(intf, dev);
1053
1054         SET_NETDEV_DEV(netdev, &intf->dev);
1055
1056         init_params_sja1000(&dev->active_params);
1057
1058         err = ems_usb_command_msg(dev, &dev->active_params);
1059         if (err) {
1060                 dev_err(netdev->dev.parent,
1061                         "couldn't initialize controller: %d\n", err);
1062                 goto cleanup_tx_msg_buffer;
1063         }
1064
1065         err = register_candev(netdev);
1066         if (err) {
1067                 dev_err(netdev->dev.parent,
1068                         "couldn't register CAN device: %d\n", err);
1069                 goto cleanup_tx_msg_buffer;
1070         }
1071
1072         return 0;
1073
1074 cleanup_tx_msg_buffer:
1075         kfree(dev->tx_msg_buffer);
1076
1077 cleanup_intr_in_buffer:
1078         kfree(dev->intr_in_buffer);
1079
1080 cleanup_intr_urb:
1081         usb_free_urb(dev->intr_urb);
1082
1083 cleanup_candev:
1084         free_candev(netdev);
1085
1086         return err;
1087 }
1088
1089 /*
1090  * called by the usb core when the device is removed from the system
1091  */
1092 static void ems_usb_disconnect(struct usb_interface *intf)
1093 {
1094         struct ems_usb *dev = usb_get_intfdata(intf);
1095
1096         usb_set_intfdata(intf, NULL);
1097
1098         if (dev) {
1099                 unregister_netdev(dev->netdev);
1100                 free_candev(dev->netdev);
1101
1102                 unlink_all_urbs(dev);
1103
1104                 usb_free_urb(dev->intr_urb);
1105
1106                 kfree(dev->intr_in_buffer);
1107         }
1108 }
1109
1110 /* usb specific object needed to register this driver with the usb subsystem */
1111 static struct usb_driver ems_usb_driver = {
1112         .name = "ems_usb",
1113         .probe = ems_usb_probe,
1114         .disconnect = ems_usb_disconnect,
1115         .id_table = ems_usb_table,
1116 };
1117
1118 static int __init ems_usb_init(void)
1119 {
1120         int err;
1121
1122         printk(KERN_INFO "CPC-USB kernel driver loaded\n");
1123
1124         /* register this driver with the USB subsystem */
1125         err = usb_register(&ems_usb_driver);
1126
1127         if (err) {
1128                 err("usb_register failed. Error number %d\n", err);
1129                 return err;
1130         }
1131
1132         return 0;
1133 }
1134
1135 static void __exit ems_usb_exit(void)
1136 {
1137         /* deregister this driver with the USB subsystem */
1138         usb_deregister(&ems_usb_driver);
1139 }
1140
1141 module_init(ems_usb_init);
1142 module_exit(ems_usb_exit);