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