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
 249         struct sk_buff *echo_skb[MAX_TX_URBS];
 250
 251         struct usb_device *udev;
 252         struct net_device *netdev;
 253
 254         atomic_t active_tx_urbs;
 255         struct usb_anchor tx_submitted;
 256         struct ems_tx_urb_context tx_contexts[MAX_TX_URBS];
 257
 258         struct usb_anchor rx_submitted;
 259
 260         struct urb *intr_urb;
 261
 262         u8 *tx_msg_buffer;
 263
 264         u8 *intr_in_buffer;
 265         unsigned int free_slots; /* remember number of available slots */
 266
 267         struct ems_cpc_msg active_params; /* active controller parameters */
 268 };
 269
 270 static void ems_usb_read_interrupt_callback(struct urb *urb)
 271 {
 272         struct ems_usb *dev = urb->context;
 273         struct net_device *netdev = dev->netdev;
 274         int err;
 275
 276         if (!netif_device_present(netdev))
 277                 return;
 278
 279         switch (urb->status) {
 280         case 0:
 281                 dev->free_slots = dev->intr_in_buffer[1];
 282                 break;
 283
 284         case -ECONNRESET: /* unlink */
 285         case -ENOENT:
 286         case -ESHUTDOWN:
 287                 return;
 288
 289         default:
 290                 netdev_info(netdev, "Rx interrupt aborted %d\n", urb->status);
 291                 break;
 292         }
 293
 294         err = usb_submit_urb(urb, GFP_ATOMIC);
 295
 296         if (err == -ENODEV)
 297                 netif_device_detach(netdev);
 298         else if (err)
 299                 netdev_err(netdev, "failed resubmitting intr urb: %d\n", err);
 300 }
 301
 302 static void ems_usb_rx_can_msg(struct ems_usb *dev, struct ems_cpc_msg *msg)
 303 {
 304         struct can_frame *cf;
 305         struct sk_buff *skb;
 306         int i;
 307         struct net_device_stats *stats = &dev->netdev->stats;
 308
 309         skb = alloc_can_skb(dev->netdev, &cf);
 310         if (skb == NULL)
 311                 return;
 312
 313         cf->can_id = le32_to_cpu(msg->msg.can_msg.id);
 314         cf->can_dlc = get_can_dlc(msg->msg.can_msg.length & 0xF);
 315
 316         if (msg->type == CPC_MSG_TYPE_EXT_CAN_FRAME ||
 317             msg->type == CPC_MSG_TYPE_EXT_RTR_FRAME)
 318                 cf->can_id |= CAN_EFF_FLAG;
 319
 320         if (msg->type == CPC_MSG_TYPE_RTR_FRAME ||
 321             msg->type == CPC_MSG_TYPE_EXT_RTR_FRAME) {
 322                 cf->can_id |= CAN_RTR_FLAG;
 323         } else {
 324                 for (i = 0; i < cf->can_dlc; i++)
 325                         cf->data[i] = msg->msg.can_msg.msg[i];
 326         }
 327
 328         netif_rx(skb);
 329
 330         stats->rx_packets++;
 331         stats->rx_bytes += cf->can_dlc;
 332 }
 333
 334 static void ems_usb_rx_err(struct ems_usb *dev, struct ems_cpc_msg *msg)
 335 {
 336         struct can_frame *cf;
 337         struct sk_buff *skb;
 338         struct net_device_stats *stats = &dev->netdev->stats;
 339
 340         skb = alloc_can_err_skb(dev->netdev, &cf);
 341         if (skb == NULL)
 342                 return;
 343
 344         if (msg->type == CPC_MSG_TYPE_CAN_STATE) {
 345                 u8 state = msg->msg.can_state;
 346
 347                 if (state & SJA1000_SR_BS) {
 348                         dev->can.state = CAN_STATE_BUS_OFF;
 349                         cf->can_id |= CAN_ERR_BUSOFF;
 350
 351                         can_bus_off(dev->netdev);
 352                 } else if (state & SJA1000_SR_ES) {
 353                         dev->can.state = CAN_STATE_ERROR_WARNING;
 354                         dev->can.can_stats.error_warning++;
 355                 } else {
 356                         dev->can.state = CAN_STATE_ERROR_ACTIVE;
 357                         dev->can.can_stats.error_passive++;
 358                 }
 359         } else if (msg->type == CPC_MSG_TYPE_CAN_FRAME_ERROR) {
 360                 u8 ecc = msg->msg.error.cc.regs.sja1000.ecc;
 361                 u8 txerr = msg->msg.error.cc.regs.sja1000.txerr;
 362                 u8 rxerr = msg->msg.error.cc.regs.sja1000.rxerr;
 363
 364                 /* bus error interrupt */
 365                 dev->can.can_stats.bus_error++;
 366                 stats->rx_errors++;
 367
 368                 cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
 369
 370                 switch (ecc & SJA1000_ECC_MASK) {
 371                 case SJA1000_ECC_BIT:
 372                         cf->data[2] |= CAN_ERR_PROT_BIT;
 373                         break;
 374                 case SJA1000_ECC_FORM:
 375                         cf->data[2] |= CAN_ERR_PROT_FORM;
 376                         break;
 377                 case SJA1000_ECC_STUFF:
 378                         cf->data[2] |= CAN_ERR_PROT_STUFF;
 379                         break;
 380                 default:
 381                         cf->data[2] |= CAN_ERR_PROT_UNSPEC;
 382                         cf->data[3] = ecc & SJA1000_ECC_SEG;
 383                         break;
 384                 }
 385
 386                 /* Error occurred during transmission? */
 387                 if ((ecc & SJA1000_ECC_DIR) == 0)
 388                         cf->data[2] |= CAN_ERR_PROT_TX;
 389
 390                 if (dev->can.state == CAN_STATE_ERROR_WARNING ||
 391                     dev->can.state == CAN_STATE_ERROR_PASSIVE) {
 392                         cf->data[1] = (txerr > rxerr) ?
 393                             CAN_ERR_CRTL_TX_PASSIVE : CAN_ERR_CRTL_RX_PASSIVE;
 394                 }
 395         } else if (msg->type == CPC_MSG_TYPE_OVERRUN) {
 396                 cf->can_id |= CAN_ERR_CRTL;
 397                 cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
 398
 399                 stats->rx_over_errors++;
 400                 stats->rx_errors++;
 401         }
 402
 403         netif_rx(skb);
 404
 405         stats->rx_packets++;
 406         stats->rx_bytes += cf->can_dlc;
 407 }
 408
 409 /*
 410  * callback for bulk IN urb
 411  */
 412 static void ems_usb_read_bulk_callback(struct urb *urb)
 413 {
 414         struct ems_usb *dev = urb->context;
 415         struct net_device *netdev;
 416         int retval;
 417
 418         netdev = dev->netdev;
 419
 420         if (!netif_device_present(netdev))
 421                 return;
 422
 423         switch (urb->status) {
 424         case 0: /* success */
 425                 break;
 426
 427         case -ENOENT:
 428                 return;
 429
 430         default:
 431                 netdev_info(netdev, "Rx URB aborted (%d)\n", urb->status);
 432                 goto resubmit_urb;
 433         }
 434
 435         if (urb->actual_length > CPC_HEADER_SIZE) {
 436                 struct ems_cpc_msg *msg;
 437                 u8 *ibuf = urb->transfer_buffer;
 438                 u8 msg_count, again, start;
 439
 440                 msg_count = ibuf[0] & ~0x80;
 441                 again = ibuf[0] & 0x80;
 442
 443                 start = CPC_HEADER_SIZE;
 444
 445                 while (msg_count) {
 446                         msg = (struct ems_cpc_msg *)&ibuf[start];
 447
 448                         switch (msg->type) {
 449                         case CPC_MSG_TYPE_CAN_STATE:
 450                                 /* Process CAN state changes */
 451                                 ems_usb_rx_err(dev, msg);
 452                                 break;
 453
 454                         case CPC_MSG_TYPE_CAN_FRAME:
 455                         case CPC_MSG_TYPE_EXT_CAN_FRAME:
 456                         case CPC_MSG_TYPE_RTR_FRAME:
 457                         case CPC_MSG_TYPE_EXT_RTR_FRAME:
 458                                 ems_usb_rx_can_msg(dev, msg);
 459                                 break;
 460
 461                         case CPC_MSG_TYPE_CAN_FRAME_ERROR:
 462                                 /* Process errorframe */
 463                                 ems_usb_rx_err(dev, msg);
 464                                 break;
 465
 466                         case CPC_MSG_TYPE_OVERRUN:
 467                                 /* Message lost while receiving */
 468                                 ems_usb_rx_err(dev, msg);
 469                                 break;
 470                         }
 471
 472                         start += CPC_MSG_HEADER_LEN + msg->length;
 473                         msg_count--;
 474
 475                         if (start > urb->transfer_buffer_length) {
 476                                 netdev_err(netdev, "format error\n");
 477                                 break;
 478                         }
 479                 }
 480         }
 481
 482 resubmit_urb:
 483         usb_fill_bulk_urb(urb, dev->udev, usb_rcvbulkpipe(dev->udev, 2),
 484                           urb->transfer_buffer, RX_BUFFER_SIZE,
 485                           ems_usb_read_bulk_callback, dev);
 486
 487         retval = usb_submit_urb(urb, GFP_ATOMIC);
 488
 489         if (retval == -ENODEV)
 490                 netif_device_detach(netdev);
 491         else if (retval)
 492                 netdev_err(netdev,
 493                            "failed resubmitting read bulk urb: %d\n", retval);
 494 }
 495
 496 /*
 497  * callback for bulk IN urb
 498  */
 499 static void ems_usb_write_bulk_callback(struct urb *urb)
 500 {
 501         struct ems_tx_urb_context *context = urb->context;
 502         struct ems_usb *dev;
 503         struct net_device *netdev;
 504
 505         BUG_ON(!context);
 506
 507         dev = context->dev;
 508         netdev = dev->netdev;
 509
 510         /* free up our allocated buffer */
 511         usb_free_coherent(urb->dev, urb->transfer_buffer_length,
 512                           urb->transfer_buffer, urb->transfer_dma);
 513
 514         atomic_dec(&dev->active_tx_urbs);
 515
 516         if (!netif_device_present(netdev))
 517                 return;
 518
 519         if (urb->status)
 520                 netdev_info(netdev, "Tx URB aborted (%d)\n", urb->status);
 521
 522         netdev->trans_start = jiffies;
 523
 524         /* transmission complete interrupt */
 525         netdev->stats.tx_packets++;
 526         netdev->stats.tx_bytes += context->dlc;
 527
 528         can_get_echo_skb(netdev, context->echo_index);
 529
 530         /* Release context */
 531         context->echo_index = MAX_TX_URBS;
 532
 533         if (netif_queue_stopped(netdev))
 534                 netif_wake_queue(netdev);
 535 }
 536
 537 /*
 538  * Send the given CPC command synchronously
 539  */
 540 static int ems_usb_command_msg(struct ems_usb *dev, struct ems_cpc_msg *msg)
 541 {
 542         int actual_length;
 543
 544         /* Copy payload */
 545         memcpy(&dev->tx_msg_buffer[CPC_HEADER_SIZE], msg,
 546                msg->length + CPC_MSG_HEADER_LEN);
 547
 548         /* Clear header */
 549         memset(&dev->tx_msg_buffer[0], 0, CPC_HEADER_SIZE);
 550
 551         return usb_bulk_msg(dev->udev, usb_sndbulkpipe(dev->udev, 2),
 552                             &dev->tx_msg_buffer[0],
 553                             msg->length + CPC_MSG_HEADER_LEN + CPC_HEADER_SIZE,
 554                             &actual_length, 1000);
 555 }
 556
 557 /*
 558  * Change CAN controllers' mode register
 559  */
 560 static int ems_usb_write_mode(struct ems_usb *dev, u8 mode)
 561 {
 562         dev->active_params.msg.can_params.cc_params.sja1000.mode = mode;
 563
 564         return ems_usb_command_msg(dev, &dev->active_params);
 565 }
 566
 567 /*
 568  * Send a CPC_Control command to change behaviour when interface receives a CAN
 569  * message, bus error or CAN state changed notifications.
 570  */
 571 static int ems_usb_control_cmd(struct ems_usb *dev, u8 val)
 572 {
 573         struct ems_cpc_msg cmd;
 574
 575         cmd.type = CPC_CMD_TYPE_CONTROL;
 576         cmd.length = CPC_MSG_HEADER_LEN + 1;
 577
 578         cmd.msgid = 0;
 579
 580         cmd.msg.generic[0] = val;
 581
 582         return ems_usb_command_msg(dev, &cmd);
 583 }
 584
 585 /*
 586  * Start interface
 587  */
 588 static int ems_usb_start(struct ems_usb *dev)
 589 {
 590         struct net_device *netdev = dev->netdev;
 591         int err, i;
 592
 593         dev->intr_in_buffer[0] = 0;
 594         dev->free_slots = 15; /* initial size */
 595
 596         for (i = 0; i < MAX_RX_URBS; i++) {
 597                 struct urb *urb = NULL;
 598                 u8 *buf = NULL;
 599
 600                 /* create a URB, and a buffer for it */
 601                 urb = usb_alloc_urb(0, GFP_KERNEL);
 602                 if (!urb) {
 603                         netdev_err(netdev, "No memory left for URBs\n");
 604                         err = -ENOMEM;
 605                         break;
 606                 }
 607
 608                 buf = usb_alloc_coherent(dev->udev, RX_BUFFER_SIZE, GFP_KERNEL,
 609                                          &urb->transfer_dma);
 610                 if (!buf) {
 611                         netdev_err(netdev, "No memory left for USB buffer\n");
 612                         usb_free_urb(urb);
 613                         err = -ENOMEM;
 614                         break;
 615                 }
 616
 617                 usb_fill_bulk_urb(urb, dev->udev, usb_rcvbulkpipe(dev->udev, 2),
 618                                   buf, RX_BUFFER_SIZE,
 619                                   ems_usb_read_bulk_callback, dev);
 620                 urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 621                 usb_anchor_urb(urb, &dev->rx_submitted);
 622
 623                 err = usb_submit_urb(urb, GFP_KERNEL);
 624                 if (err) {
 625                         usb_unanchor_urb(urb);
 626                         usb_free_coherent(dev->udev, RX_BUFFER_SIZE, buf,
 627                                           urb->transfer_dma);
 628                         break;
 629                 }
 630
 631                 /* Drop reference, USB core will take care of freeing it */
 632                 usb_free_urb(urb);
 633         }
 634
 635         /* Did we submit any URBs */
 636         if (i == 0) {
 637                 netdev_warn(netdev, "couldn't setup read URBs\n");
 638                 return err;
 639         }
 640
 641         /* Warn if we've couldn't transmit all the URBs */
 642         if (i < MAX_RX_URBS)
 643                 netdev_warn(netdev, "rx performance may be slow\n");
 644
 645         /* Setup and start interrupt URB */
 646         usb_fill_int_urb(dev->intr_urb, dev->udev,
 647                          usb_rcvintpipe(dev->udev, 1),
 648                          dev->intr_in_buffer,
 649                          INTR_IN_BUFFER_SIZE,
 650                          ems_usb_read_interrupt_callback, dev, 1);
 651
 652         err = usb_submit_urb(dev->intr_urb, GFP_KERNEL);
 653         if (err) {
 654                 netdev_warn(netdev, "intr URB submit failed: %d\n", err);
 655
 656                 return err;
 657         }
 658
 659         /* CPC-USB will transfer received message to host */
 660         err = ems_usb_control_cmd(dev, CONTR_CAN_MESSAGE | CONTR_CONT_ON);
 661         if (err)
 662                 goto failed;
 663
 664         /* CPC-USB will transfer CAN state changes to host */
 665         err = ems_usb_control_cmd(dev, CONTR_CAN_STATE | CONTR_CONT_ON);
 666         if (err)
 667                 goto failed;
 668
 669         /* CPC-USB will transfer bus errors to host */
 670         err = ems_usb_control_cmd(dev, CONTR_BUS_ERROR | CONTR_CONT_ON);
 671         if (err)
 672                 goto failed;
 673
 674         err = ems_usb_write_mode(dev, SJA1000_MOD_NORMAL);
 675         if (err)
 676                 goto failed;
 677
 678         dev->can.state = CAN_STATE_ERROR_ACTIVE;
 679
 680         return 0;
 681
 682 failed:
 683         netdev_warn(netdev, "couldn't submit control: %d\n", err);
 684
 685         return err;
 686 }
 687
 688 static void unlink_all_urbs(struct ems_usb *dev)
 689 {
 690         int i;
 691
 692         usb_unlink_urb(dev->intr_urb);
 693
 694         usb_kill_anchored_urbs(&dev->rx_submitted);
 695
 696         usb_kill_anchored_urbs(&dev->tx_submitted);
 697         atomic_set(&dev->active_tx_urbs, 0);
 698
 699         for (i = 0; i < MAX_TX_URBS; i++)
 700                 dev->tx_contexts[i].echo_index = MAX_TX_URBS;
 701 }
 702
 703 static int ems_usb_open(struct net_device *netdev)
 704 {
 705         struct ems_usb *dev = netdev_priv(netdev);
 706         int err;
 707
 708         err = ems_usb_write_mode(dev, SJA1000_MOD_RM);
 709         if (err)
 710                 return err;
 711
 712         /* common open */
 713         err = open_candev(netdev);
 714         if (err)
 715                 return err;
 716
 717         /* finally start device */
 718         err = ems_usb_start(dev);
 719         if (err) {
 720                 if (err == -ENODEV)
 721                         netif_device_detach(dev->netdev);
 722
 723                 netdev_warn(netdev, "couldn't start device: %d\n", err);
 724
 725                 close_candev(netdev);
 726
 727                 return err;
 728         }
 729
 730
 731         netif_start_queue(netdev);
 732
 733         return 0;
 734 }
 735
 736 static netdev_tx_t ems_usb_start_xmit(struct sk_buff *skb, struct net_device *netdev)
 737 {
 738         struct ems_usb *dev = netdev_priv(netdev);
 739         struct ems_tx_urb_context *context = NULL;
 740         struct net_device_stats *stats = &netdev->stats;
 741         struct can_frame *cf = (struct can_frame *)skb->data;
 742         struct ems_cpc_msg *msg;
 743         struct urb *urb;
 744         u8 *buf;
 745         int i, err;
 746         size_t size = CPC_HEADER_SIZE + CPC_MSG_HEADER_LEN
 747                         + sizeof(struct cpc_can_msg);
 748
 749         if (can_dropped_invalid_skb(netdev, skb))
 750                 return NETDEV_TX_OK;
 751
 752         /* create a URB, and a buffer for it, and copy the data to the URB */
 753         urb = usb_alloc_urb(0, GFP_ATOMIC);
 754         if (!urb) {
 755                 netdev_err(netdev, "No memory left for URBs\n");
 756                 goto nomem;
 757         }
 758
 759         buf = usb_alloc_coherent(dev->udev, size, GFP_ATOMIC, &urb->transfer_dma);
 760         if (!buf) {
 761                 netdev_err(netdev, "No memory left for USB buffer\n");
 762                 usb_free_urb(urb);
 763                 goto nomem;
 764         }
 765
 766         msg = (struct ems_cpc_msg *)&buf[CPC_HEADER_SIZE];
 767
 768         msg->msg.can_msg.id = cf->can_id & CAN_ERR_MASK;
 769         msg->msg.can_msg.length = cf->can_dlc;
 770
 771         if (cf->can_id & CAN_RTR_FLAG) {
 772                 msg->type = cf->can_id & CAN_EFF_FLAG ?
 773                         CPC_CMD_TYPE_EXT_RTR_FRAME : CPC_CMD_TYPE_RTR_FRAME;
 774
 775                 msg->length = CPC_CAN_MSG_MIN_SIZE;
 776         } else {
 777                 msg->type = cf->can_id & CAN_EFF_FLAG ?
 778                         CPC_CMD_TYPE_EXT_CAN_FRAME : CPC_CMD_TYPE_CAN_FRAME;
 779
 780                 for (i = 0; i < cf->can_dlc; i++)
 781                         msg->msg.can_msg.msg[i] = cf->data[i];
 782
 783                 msg->length = CPC_CAN_MSG_MIN_SIZE + cf->can_dlc;
 784         }
 785
 786         /* Respect byte order */
 787         msg->msg.can_msg.id = cpu_to_le32(msg->msg.can_msg.id);
 788
 789         for (i = 0; i < MAX_TX_URBS; i++) {
 790                 if (dev->tx_contexts[i].echo_index == MAX_TX_URBS) {
 791                         context = &dev->tx_contexts[i];
 792                         break;
 793                 }
 794         }
 795
 796         /*
 797          * May never happen! When this happens we'd more URBs in flight as
 798          * allowed (MAX_TX_URBS).
 799          */
 800         if (!context) {
 801                 usb_unanchor_urb(urb);
 802                 usb_free_coherent(dev->udev, size, buf, urb->transfer_dma);
 803
 804                 netdev_warn(netdev, "couldn't find free context\n");
 805
 806                 return NETDEV_TX_BUSY;
 807         }
 808
 809         context->dev = dev;
 810         context->echo_index = i;
 811         context->dlc = cf->can_dlc;
 812
 813         usb_fill_bulk_urb(urb, dev->udev, usb_sndbulkpipe(dev->udev, 2), buf,
 814                           size, ems_usb_write_bulk_callback, context);
 815         urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 816         usb_anchor_urb(urb, &dev->tx_submitted);
 817
 818         can_put_echo_skb(skb, netdev, context->echo_index);
 819
 820         atomic_inc(&dev->active_tx_urbs);
 821
 822         err = usb_submit_urb(urb, GFP_ATOMIC);
 823         if (unlikely(err)) {
 824                 can_free_echo_skb(netdev, context->echo_index);
 825
 826                 usb_unanchor_urb(urb);
 827                 usb_free_coherent(dev->udev, size, buf, urb->transfer_dma);
 828                 dev_kfree_skb(skb);
 829
 830                 atomic_dec(&dev->active_tx_urbs);
 831
 832                 if (err == -ENODEV) {
 833                         netif_device_detach(netdev);
 834                 } else {
 835                         netdev_warn(netdev, "failed tx_urb %d\n", err);
 836
 837                         stats->tx_dropped++;
 838                 }
 839         } else {
 840                 netdev->trans_start = jiffies;
 841
 842                 /* Slow down tx path */
 843                 if (atomic_read(&dev->active_tx_urbs) >= MAX_TX_URBS ||
 844                     dev->free_slots < 5) {
 845                         netif_stop_queue(netdev);
 846                 }
 847         }
 848
 849         /*
 850          * Release our reference to this URB, the USB core will eventually free
 851          * it entirely.
 852          */
 853         usb_free_urb(urb);
 854
 855         return NETDEV_TX_OK;
 856
 857 nomem:
 858         dev_kfree_skb(skb);
 859         stats->tx_dropped++;
 860
 861         return NETDEV_TX_OK;
 862 }
 863
 864 static int ems_usb_close(struct net_device *netdev)
 865 {
 866         struct ems_usb *dev = netdev_priv(netdev);
 867
 868         /* Stop polling */
 869         unlink_all_urbs(dev);
 870
 871         netif_stop_queue(netdev);
 872
 873         /* Set CAN controller to reset mode */
 874         if (ems_usb_write_mode(dev, SJA1000_MOD_RM))
 875                 netdev_warn(netdev, "couldn't stop device");
 876
 877         close_candev(netdev);
 878
 879         return 0;
 880 }
 881
 882 static const struct net_device_ops ems_usb_netdev_ops = {
 883         .ndo_open = ems_usb_open,
 884         .ndo_stop = ems_usb_close,
 885         .ndo_start_xmit = ems_usb_start_xmit,
 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);