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 #define CPC_TX_QUEUE_TRIGGER_LOW        25
 121 #define CPC_TX_QUEUE_TRIGGER_HIGH       35
 122
 123 /*
 124  * CAN-Message representation in a CPC_MSG. Message object type is
 125  * CPC_MSG_TYPE_CAN_FRAME or CPC_MSG_TYPE_RTR_FRAME or
 126  * CPC_MSG_TYPE_EXT_CAN_FRAME or CPC_MSG_TYPE_EXT_RTR_FRAME.
 127  */
 128 struct cpc_can_msg {
 129         __le32 id;
 130         u8 length;
 131         u8 msg[8];
 132 };
 133
 134 /* Representation of the CAN parameters for the SJA1000 controller */
 135 struct cpc_sja1000_params {
 136         u8 mode;
 137         u8 acc_code0;
 138         u8 acc_code1;
 139         u8 acc_code2;
 140         u8 acc_code3;
 141         u8 acc_mask0;
 142         u8 acc_mask1;
 143         u8 acc_mask2;
 144         u8 acc_mask3;
 145         u8 btr0;
 146         u8 btr1;
 147         u8 outp_contr;
 148 };
 149
 150 /* CAN params message representation */
 151 struct cpc_can_params {
 152         u8 cc_type;
 153
 154         /* Will support M16C CAN controller in the future */
 155         union {
 156                 struct cpc_sja1000_params sja1000;
 157         } cc_params;
 158 };
 159
 160 /* Structure for confirmed message handling */
 161 struct cpc_confirm {
 162         u8 error; /* error code */
 163 };
 164
 165 /* Structure for overrun conditions */
 166 struct cpc_overrun {
 167         u8 event;
 168         u8 count;
 169 };
 170
 171 /* SJA1000 CAN errors (compatible to NXP LPC2119) */
 172 struct cpc_sja1000_can_error {
 173         u8 ecc;
 174         u8 rxerr;
 175         u8 txerr;
 176 };
 177
 178 /* structure for CAN error conditions */
 179 struct cpc_can_error {
 180         u8 ecode;
 181
 182         struct {
 183                 u8 cc_type;
 184
 185                 /* Other controllers may also provide error code capture regs */
 186                 union {
 187                         struct cpc_sja1000_can_error sja1000;
 188                 } regs;
 189         } cc;
 190 };
 191
 192 /*
 193  * Structure containing RX/TX error counter. This structure is used to request
 194  * the values of the CAN controllers TX and RX error counter.
 195  */
 196 struct cpc_can_err_counter {
 197         u8 rx;
 198         u8 tx;
 199 };
 200
 201 /* Main message type used between library and application */
 202 struct __packed ems_cpc_msg {
 203         u8 type;        /* type of message */
 204         u8 length;      /* length of data within union 'msg' */
 205         u8 msgid;       /* confirmation handle */
 206         __le32 ts_sec;  /* timestamp in seconds */
 207         __le32 ts_nsec; /* timestamp in nano seconds */
 208
 209         union {
 210                 u8 generic[64];
 211                 struct cpc_can_msg can_msg;
 212                 struct cpc_can_params can_params;
 213                 struct cpc_confirm confirmation;
 214                 struct cpc_overrun overrun;
 215                 struct cpc_can_error error;
 216                 struct cpc_can_err_counter err_counter;
 217                 u8 can_state;
 218         } msg;
 219 };
 220
 221 /*
 222  * Table of devices that work with this driver
 223  * NOTE: This driver supports only CPC-USB/ARM7 (LPC2119) yet.
 224  */
 225 static struct usb_device_id ems_usb_table[] = {
 226         {USB_DEVICE(USB_CPCUSB_VENDOR_ID, USB_CPCUSB_ARM7_PRODUCT_ID)},
 227         {} /* Terminating entry */
 228 };
 229
 230 MODULE_DEVICE_TABLE(usb, ems_usb_table);
 231
 232 #define RX_BUFFER_SIZE      64
 233 #define CPC_HEADER_SIZE     4
 234 #define INTR_IN_BUFFER_SIZE 4
 235
 236 #define MAX_RX_URBS 10
 237 #define MAX_TX_URBS 10
 238
 239 struct ems_usb;
 240
 241 struct ems_tx_urb_context {
 242         struct ems_usb *dev;
 243
 244         u32 echo_index;
 245         u8 dlc;
 246 };
 247
 248 struct ems_usb {
 249         struct can_priv can; /* must be the first member */
 250
 251         struct sk_buff *echo_skb[MAX_TX_URBS];
 252
 253         struct usb_device *udev;
 254         struct net_device *netdev;
 255
 256         atomic_t active_tx_urbs;
 257         struct usb_anchor tx_submitted;
 258         struct ems_tx_urb_context tx_contexts[MAX_TX_URBS];
 259
 260         struct usb_anchor rx_submitted;
 261
 262         struct urb *intr_urb;
 263
 264         u8 *tx_msg_buffer;
 265
 266         u8 *intr_in_buffer;
 267         unsigned int free_slots; /* remember number of available slots */
 268
 269         struct ems_cpc_msg active_params; /* active controller parameters */
 270 };
 271
 272 static void ems_usb_read_interrupt_callback(struct urb *urb)
 273 {
 274         struct ems_usb *dev = urb->context;
 275         struct net_device *netdev = dev->netdev;
 276         int err;
 277
 278         if (!netif_device_present(netdev))
 279                 return;
 280
 281         switch (urb->status) {
 282         case 0:
 283                 dev->free_slots = dev->intr_in_buffer[1];
 284                 if (dev->free_slots > CPC_TX_QUEUE_TRIGGER_HIGH &&
 285                     netif_queue_stopped(netdev))
 286                         netif_wake_queue(netdev);
 287                 break;
 288
 289         case -ECONNRESET: /* unlink */
 290         case -ENOENT:
 291         case -ESHUTDOWN:
 292                 return;
 293
 294         default:
 295                 netdev_info(netdev, "Rx interrupt aborted %d\n", urb->status);
 296                 break;
 297         }
 298
 299         err = usb_submit_urb(urb, GFP_ATOMIC);
 300
 301         if (err == -ENODEV)
 302                 netif_device_detach(netdev);
 303         else if (err)
 304                 netdev_err(netdev, "failed resubmitting intr urb: %d\n", err);
 305 }
 306
 307 static void ems_usb_rx_can_msg(struct ems_usb *dev, struct ems_cpc_msg *msg)
 308 {
 309         struct can_frame *cf;
 310         struct sk_buff *skb;
 311         int i;
 312         struct net_device_stats *stats = &dev->netdev->stats;
 313
 314         skb = alloc_can_skb(dev->netdev, &cf);
 315         if (skb == NULL)
 316                 return;
 317
 318         cf->can_id = le32_to_cpu(msg->msg.can_msg.id);
 319         cf->can_dlc = get_can_dlc(msg->msg.can_msg.length & 0xF);
 320
 321         if (msg->type == CPC_MSG_TYPE_EXT_CAN_FRAME ||
 322             msg->type == CPC_MSG_TYPE_EXT_RTR_FRAME)
 323                 cf->can_id |= CAN_EFF_FLAG;
 324
 325         if (msg->type == CPC_MSG_TYPE_RTR_FRAME ||
 326             msg->type == CPC_MSG_TYPE_EXT_RTR_FRAME) {
 327                 cf->can_id |= CAN_RTR_FLAG;
 328         } else {
 329                 for (i = 0; i < cf->can_dlc; i++)
 330                         cf->data[i] = msg->msg.can_msg.msg[i];
 331         }
 332
 333         stats->rx_packets++;
 334         stats->rx_bytes += cf->can_dlc;
 335         netif_rx(skb);
 336 }
 337
 338 static void ems_usb_rx_err(struct ems_usb *dev, struct ems_cpc_msg *msg)
 339 {
 340         struct can_frame *cf;
 341         struct sk_buff *skb;
 342         struct net_device_stats *stats = &dev->netdev->stats;
 343
 344         skb = alloc_can_err_skb(dev->netdev, &cf);
 345         if (skb == NULL)
 346                 return;
 347
 348         if (msg->type == CPC_MSG_TYPE_CAN_STATE) {
 349                 u8 state = msg->msg.can_state;
 350
 351                 if (state & SJA1000_SR_BS) {
 352                         dev->can.state = CAN_STATE_BUS_OFF;
 353                         cf->can_id |= CAN_ERR_BUSOFF;
 354
 355                         dev->can.can_stats.bus_off++;
 356                         can_bus_off(dev->netdev);
 357                 } else if (state & SJA1000_SR_ES) {
 358                         dev->can.state = CAN_STATE_ERROR_WARNING;
 359                         dev->can.can_stats.error_warning++;
 360                 } else {
 361                         dev->can.state = CAN_STATE_ERROR_ACTIVE;
 362                         dev->can.can_stats.error_passive++;
 363                 }
 364         } else if (msg->type == CPC_MSG_TYPE_CAN_FRAME_ERROR) {
 365                 u8 ecc = msg->msg.error.cc.regs.sja1000.ecc;
 366                 u8 txerr = msg->msg.error.cc.regs.sja1000.txerr;
 367                 u8 rxerr = msg->msg.error.cc.regs.sja1000.rxerr;
 368
 369                 /* bus error interrupt */
 370                 dev->can.can_stats.bus_error++;
 371                 stats->rx_errors++;
 372
 373                 cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
 374
 375                 switch (ecc & SJA1000_ECC_MASK) {
 376                 case SJA1000_ECC_BIT:
 377                         cf->data[2] |= CAN_ERR_PROT_BIT;
 378                         break;
 379                 case SJA1000_ECC_FORM:
 380                         cf->data[2] |= CAN_ERR_PROT_FORM;
 381                         break;
 382                 case SJA1000_ECC_STUFF:
 383                         cf->data[2] |= CAN_ERR_PROT_STUFF;
 384                         break;
 385                 default:
 386                         cf->data[3] = ecc & SJA1000_ECC_SEG;
 387                         break;
 388                 }
 389
 390                 /* Error occurred during transmission? */
 391                 if ((ecc & SJA1000_ECC_DIR) == 0)
 392                         cf->data[2] |= CAN_ERR_PROT_TX;
 393
 394                 if (dev->can.state == CAN_STATE_ERROR_WARNING ||
 395                     dev->can.state == CAN_STATE_ERROR_PASSIVE) {
 396                         cf->data[1] = (txerr > rxerr) ?
 397                             CAN_ERR_CRTL_TX_PASSIVE : CAN_ERR_CRTL_RX_PASSIVE;
 398                 }
 399         } else if (msg->type == CPC_MSG_TYPE_OVERRUN) {
 400                 cf->can_id |= CAN_ERR_CRTL;
 401                 cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
 402
 403                 stats->rx_over_errors++;
 404                 stats->rx_errors++;
 405         }
 406
 407         stats->rx_packets++;
 408         stats->rx_bytes += cf->can_dlc;
 409         netif_rx(skb);
 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                 netdev_info(netdev, "Rx URB aborted (%d)\n", urb->status);
 435                 goto resubmit_urb;
 436         }
 437
 438         if (urb->actual_length > CPC_HEADER_SIZE) {
 439                 struct ems_cpc_msg *msg;
 440                 u8 *ibuf = urb->transfer_buffer;
 441                 u8 msg_count, start;
 442
 443                 msg_count = ibuf[0] & ~0x80;
 444
 445                 start = CPC_HEADER_SIZE;
 446
 447                 while (msg_count) {
 448                         msg = (struct ems_cpc_msg *)&ibuf[start];
 449
 450                         switch (msg->type) {
 451                         case CPC_MSG_TYPE_CAN_STATE:
 452                                 /* Process CAN state changes */
 453                                 ems_usb_rx_err(dev, msg);
 454                                 break;
 455
 456                         case CPC_MSG_TYPE_CAN_FRAME:
 457                         case CPC_MSG_TYPE_EXT_CAN_FRAME:
 458                         case CPC_MSG_TYPE_RTR_FRAME:
 459                         case CPC_MSG_TYPE_EXT_RTR_FRAME:
 460                                 ems_usb_rx_can_msg(dev, msg);
 461                                 break;
 462
 463                         case CPC_MSG_TYPE_CAN_FRAME_ERROR:
 464                                 /* Process errorframe */
 465                                 ems_usb_rx_err(dev, msg);
 466                                 break;
 467
 468                         case CPC_MSG_TYPE_OVERRUN:
 469                                 /* Message lost while receiving */
 470                                 ems_usb_rx_err(dev, msg);
 471                                 break;
 472                         }
 473
 474                         start += CPC_MSG_HEADER_LEN + msg->length;
 475                         msg_count--;
 476
 477                         if (start > urb->transfer_buffer_length) {
 478                                 netdev_err(netdev, "format error\n");
 479                                 break;
 480                         }
 481                 }
 482         }
 483
 484 resubmit_urb:
 485         usb_fill_bulk_urb(urb, dev->udev, usb_rcvbulkpipe(dev->udev, 2),
 486                           urb->transfer_buffer, RX_BUFFER_SIZE,
 487                           ems_usb_read_bulk_callback, dev);
 488
 489         retval = usb_submit_urb(urb, GFP_ATOMIC);
 490
 491         if (retval == -ENODEV)
 492                 netif_device_detach(netdev);
 493         else if (retval)
 494                 netdev_err(netdev,
 495                            "failed resubmitting read bulk urb: %d\n", retval);
 496 }
 497
 498 /*
 499  * callback for bulk IN urb
 500  */
 501 static void ems_usb_write_bulk_callback(struct urb *urb)
 502 {
 503         struct ems_tx_urb_context *context = urb->context;
 504         struct ems_usb *dev;
 505         struct net_device *netdev;
 506
 507         BUG_ON(!context);
 508
 509         dev = context->dev;
 510         netdev = dev->netdev;
 511
 512         /* free up our allocated buffer */
 513         usb_free_coherent(urb->dev, urb->transfer_buffer_length,
 514                           urb->transfer_buffer, urb->transfer_dma);
 515
 516         atomic_dec(&dev->active_tx_urbs);
 517
 518         if (!netif_device_present(netdev))
 519                 return;
 520
 521         if (urb->status)
 522                 netdev_info(netdev, "Tx URB aborted (%d)\n", urb->status);
 523
 524         netif_trans_update(netdev);
 525
 526         /* transmission complete interrupt */
 527         netdev->stats.tx_packets++;
 528         netdev->stats.tx_bytes += context->dlc;
 529
 530         can_get_echo_skb(netdev, context->echo_index);
 531
 532         /* Release context */
 533         context->echo_index = MAX_TX_URBS;
 534
 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 = 50; /* 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                         usb_free_urb(urb);
 629                         break;
 630                 }
 631
 632                 /* Drop reference, USB core will take care of freeing it */
 633                 usb_free_urb(urb);
 634         }
 635
 636         /* Did we submit any URBs */
 637         if (i == 0) {
 638                 netdev_warn(netdev, "couldn't setup read URBs\n");
 639                 return err;
 640         }
 641
 642         /* Warn if we've couldn't transmit all the URBs */
 643         if (i < MAX_RX_URBS)
 644                 netdev_warn(netdev, "rx performance may be slow\n");
 645
 646         /* Setup and start interrupt URB */
 647         usb_fill_int_urb(dev->intr_urb, dev->udev,
 648                          usb_rcvintpipe(dev->udev, 1),
 649                          dev->intr_in_buffer,
 650                          INTR_IN_BUFFER_SIZE,
 651                          ems_usb_read_interrupt_callback, dev, 1);
 652
 653         err = usb_submit_urb(dev->intr_urb, GFP_KERNEL);
 654         if (err) {
 655                 netdev_warn(netdev, "intr URB submit failed: %d\n", err);
 656
 657                 return err;
 658         }
 659
 660         /* CPC-USB will transfer received message to host */
 661         err = ems_usb_control_cmd(dev, CONTR_CAN_MESSAGE | CONTR_CONT_ON);
 662         if (err)
 663                 goto failed;
 664
 665         /* CPC-USB will transfer CAN state changes to host */
 666         err = ems_usb_control_cmd(dev, CONTR_CAN_STATE | CONTR_CONT_ON);
 667         if (err)
 668                 goto failed;
 669
 670         /* CPC-USB will transfer bus errors to host */
 671         err = ems_usb_control_cmd(dev, CONTR_BUS_ERROR | CONTR_CONT_ON);
 672         if (err)
 673                 goto failed;
 674
 675         err = ems_usb_write_mode(dev, SJA1000_MOD_NORMAL);
 676         if (err)
 677                 goto failed;
 678
 679         dev->can.state = CAN_STATE_ERROR_ACTIVE;
 680
 681         return 0;
 682
 683 failed:
 684         netdev_warn(netdev, "couldn't submit control: %d\n", err);
 685
 686         return err;
 687 }
 688
 689 static void unlink_all_urbs(struct ems_usb *dev)
 690 {
 691         int i;
 692
 693         usb_unlink_urb(dev->intr_urb);
 694
 695         usb_kill_anchored_urbs(&dev->rx_submitted);
 696
 697         usb_kill_anchored_urbs(&dev->tx_submitted);
 698         atomic_set(&dev->active_tx_urbs, 0);
 699
 700         for (i = 0; i < MAX_TX_URBS; i++)
 701                 dev->tx_contexts[i].echo_index = MAX_TX_URBS;
 702 }
 703
 704 static int ems_usb_open(struct net_device *netdev)
 705 {
 706         struct ems_usb *dev = netdev_priv(netdev);
 707         int err;
 708
 709         err = ems_usb_write_mode(dev, SJA1000_MOD_RM);
 710         if (err)
 711                 return err;
 712
 713         /* common open */
 714         err = open_candev(netdev);
 715         if (err)
 716                 return err;
 717
 718         /* finally start device */
 719         err = ems_usb_start(dev);
 720         if (err) {
 721                 if (err == -ENODEV)
 722                         netif_device_detach(dev->netdev);
 723
 724                 netdev_warn(netdev, "couldn't start device: %d\n", err);
 725
 726                 close_candev(netdev);
 727
 728                 return err;
 729         }
 730
 731
 732         netif_start_queue(netdev);
 733
 734         return 0;
 735 }
 736
 737 static netdev_tx_t ems_usb_start_xmit(struct sk_buff *skb, struct net_device *netdev)
 738 {
 739         struct ems_usb *dev = netdev_priv(netdev);
 740         struct ems_tx_urb_context *context = NULL;
 741         struct net_device_stats *stats = &netdev->stats;
 742         struct can_frame *cf = (struct can_frame *)skb->data;
 743         struct ems_cpc_msg *msg;
 744         struct urb *urb;
 745         u8 *buf;
 746         int i, err;
 747         size_t size = CPC_HEADER_SIZE + CPC_MSG_HEADER_LEN
 748                         + sizeof(struct cpc_can_msg);
 749
 750         if (can_dropped_invalid_skb(netdev, skb))
 751                 return NETDEV_TX_OK;
 752
 753         /* create a URB, and a buffer for it, and copy the data to the URB */
 754         urb = usb_alloc_urb(0, GFP_ATOMIC);
 755         if (!urb) {
 756                 netdev_err(netdev, "No memory left for URBs\n");
 757                 goto nomem;
 758         }
 759
 760         buf = usb_alloc_coherent(dev->udev, size, GFP_ATOMIC, &urb->transfer_dma);
 761         if (!buf) {
 762                 netdev_err(netdev, "No memory left for USB buffer\n");
 763                 usb_free_urb(urb);
 764                 goto nomem;
 765         }
 766
 767         msg = (struct ems_cpc_msg *)&buf[CPC_HEADER_SIZE];
 768
 769         msg->msg.can_msg.id = cpu_to_le32(cf->can_id & CAN_ERR_MASK);
 770         msg->msg.can_msg.length = cf->can_dlc;
 771
 772         if (cf->can_id & CAN_RTR_FLAG) {
 773                 msg->type = cf->can_id & CAN_EFF_FLAG ?
 774                         CPC_CMD_TYPE_EXT_RTR_FRAME : CPC_CMD_TYPE_RTR_FRAME;
 775
 776                 msg->length = CPC_CAN_MSG_MIN_SIZE;
 777         } else {
 778                 msg->type = cf->can_id & CAN_EFF_FLAG ?
 779                         CPC_CMD_TYPE_EXT_CAN_FRAME : CPC_CMD_TYPE_CAN_FRAME;
 780
 781                 for (i = 0; i < cf->can_dlc; i++)
 782                         msg->msg.can_msg.msg[i] = cf->data[i];
 783
 784                 msg->length = CPC_CAN_MSG_MIN_SIZE + cf->can_dlc;
 785         }
 786
 787         for (i = 0; i < MAX_TX_URBS; i++) {
 788                 if (dev->tx_contexts[i].echo_index == MAX_TX_URBS) {
 789                         context = &dev->tx_contexts[i];
 790                         break;
 791                 }
 792         }
 793
 794         /*
 795          * May never happen! When this happens we'd more URBs in flight as
 796          * allowed (MAX_TX_URBS).
 797          */
 798         if (!context) {
 799                 usb_free_coherent(dev->udev, size, buf, urb->transfer_dma);
 800                 usb_free_urb(urb);
 801
 802                 netdev_warn(netdev, "couldn't find free context\n");
 803
 804                 return NETDEV_TX_BUSY;
 805         }
 806
 807         context->dev = dev;
 808         context->echo_index = i;
 809         context->dlc = cf->can_dlc;
 810
 811         usb_fill_bulk_urb(urb, dev->udev, usb_sndbulkpipe(dev->udev, 2), buf,
 812                           size, ems_usb_write_bulk_callback, context);
 813         urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 814         usb_anchor_urb(urb, &dev->tx_submitted);
 815
 816         can_put_echo_skb(skb, netdev, context->echo_index);
 817
 818         atomic_inc(&dev->active_tx_urbs);
 819
 820         err = usb_submit_urb(urb, GFP_ATOMIC);
 821         if (unlikely(err)) {
 822                 can_free_echo_skb(netdev, context->echo_index);
 823
 824                 usb_unanchor_urb(urb);
 825                 usb_free_coherent(dev->udev, size, buf, urb->transfer_dma);
 826                 dev_kfree_skb(skb);
 827
 828                 atomic_dec(&dev->active_tx_urbs);
 829
 830                 if (err == -ENODEV) {
 831                         netif_device_detach(netdev);
 832                 } else {
 833                         netdev_warn(netdev, "failed tx_urb %d\n", err);
 834
 835                         stats->tx_dropped++;
 836                 }
 837         } else {
 838                 netif_trans_update(netdev);
 839
 840                 /* Slow down tx path */
 841                 if (atomic_read(&dev->active_tx_urbs) >= MAX_TX_URBS ||
 842                     dev->free_slots < CPC_TX_QUEUE_TRIGGER_LOW) {
 843                         netif_stop_queue(netdev);
 844                 }
 845         }
 846
 847         /*
 848          * Release our reference to this URB, the USB core will eventually free
 849          * it entirely.
 850          */
 851         usb_free_urb(urb);
 852
 853         return NETDEV_TX_OK;
 854
 855 nomem:
 856         dev_kfree_skb(skb);
 857         stats->tx_dropped++;
 858
 859         return NETDEV_TX_OK;
 860 }
 861
 862 static int ems_usb_close(struct net_device *netdev)
 863 {
 864         struct ems_usb *dev = netdev_priv(netdev);
 865
 866         /* Stop polling */
 867         unlink_all_urbs(dev);
 868
 869         netif_stop_queue(netdev);
 870
 871         /* Set CAN controller to reset mode */
 872         if (ems_usb_write_mode(dev, SJA1000_MOD_RM))
 873                 netdev_warn(netdev, "couldn't stop device");
 874
 875         close_candev(netdev);
 876
 877         return 0;
 878 }
 879
 880 static const struct net_device_ops ems_usb_netdev_ops = {
 881         .ndo_open = ems_usb_open,
 882         .ndo_stop = ems_usb_close,
 883         .ndo_start_xmit = ems_usb_start_xmit,
 884         .ndo_change_mtu = can_change_mtu,
 885 };
 886
 887 static const struct can_bittiming_const ems_usb_bittiming_const = {
 888         .name = "ems_usb",
 889         .tseg1_min = 1,
 890         .tseg1_max = 16,
 891         .tseg2_min = 1,
 892         .tseg2_max = 8,
 893         .sjw_max = 4,
 894         .brp_min = 1,
 895         .brp_max = 64,
 896         .brp_inc = 1,
 897 };
 898
 899 static int ems_usb_set_mode(struct net_device *netdev, enum can_mode mode)
 900 {
 901         struct ems_usb *dev = netdev_priv(netdev);
 902
 903         switch (mode) {
 904         case CAN_MODE_START:
 905                 if (ems_usb_write_mode(dev, SJA1000_MOD_NORMAL))
 906                         netdev_warn(netdev, "couldn't start device");
 907
 908                 if (netif_queue_stopped(netdev))
 909                         netif_wake_queue(netdev);
 910                 break;
 911
 912         default:
 913                 return -EOPNOTSUPP;
 914         }
 915
 916         return 0;
 917 }
 918
 919 static int ems_usb_set_bittiming(struct net_device *netdev)
 920 {
 921         struct ems_usb *dev = netdev_priv(netdev);
 922         struct can_bittiming *bt = &dev->can.bittiming;
 923         u8 btr0, btr1;
 924
 925         btr0 = ((bt->brp - 1) & 0x3f) | (((bt->sjw - 1) & 0x3) << 6);
 926         btr1 = ((bt->prop_seg + bt->phase_seg1 - 1) & 0xf) |
 927                 (((bt->phase_seg2 - 1) & 0x7) << 4);
 928         if (dev->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES)
 929                 btr1 |= 0x80;
 930
 931         netdev_info(netdev, "setting BTR0=0x%02x BTR1=0x%02x\n", btr0, btr1);
 932
 933         dev->active_params.msg.can_params.cc_params.sja1000.btr0 = btr0;
 934         dev->active_params.msg.can_params.cc_params.sja1000.btr1 = btr1;
 935
 936         return ems_usb_command_msg(dev, &dev->active_params);
 937 }
 938
 939 static void init_params_sja1000(struct ems_cpc_msg *msg)
 940 {
 941         struct cpc_sja1000_params *sja1000 =
 942                 &msg->msg.can_params.cc_params.sja1000;
 943
 944         msg->type = CPC_CMD_TYPE_CAN_PARAMS;
 945         msg->length = sizeof(struct cpc_can_params);
 946         msg->msgid = 0;
 947
 948         msg->msg.can_params.cc_type = CPC_CC_TYPE_SJA1000;
 949
 950         /* Acceptance filter open */
 951         sja1000->acc_code0 = 0x00;
 952         sja1000->acc_code1 = 0x00;
 953         sja1000->acc_code2 = 0x00;
 954         sja1000->acc_code3 = 0x00;
 955
 956         /* Acceptance filter open */
 957         sja1000->acc_mask0 = 0xFF;
 958         sja1000->acc_mask1 = 0xFF;
 959         sja1000->acc_mask2 = 0xFF;
 960         sja1000->acc_mask3 = 0xFF;
 961
 962         sja1000->btr0 = 0;
 963         sja1000->btr1 = 0;
 964
 965         sja1000->outp_contr = SJA1000_DEFAULT_OUTPUT_CONTROL;
 966         sja1000->mode = SJA1000_MOD_RM;
 967 }
 968
 969 /*
 970  * probe function for new CPC-USB devices
 971  */
 972 static int ems_usb_probe(struct usb_interface *intf,
 973                          const struct usb_device_id *id)
 974 {
 975         struct net_device *netdev;
 976         struct ems_usb *dev;
 977         int i, err = -ENOMEM;
 978
 979         netdev = alloc_candev(sizeof(struct ems_usb), MAX_TX_URBS);
 980         if (!netdev) {
 981                 dev_err(&intf->dev, "ems_usb: Couldn't alloc candev\n");
 982                 return -ENOMEM;
 983         }
 984
 985         dev = netdev_priv(netdev);
 986
 987         dev->udev = interface_to_usbdev(intf);
 988         dev->netdev = netdev;
 989
 990         dev->can.state = CAN_STATE_STOPPED;
 991         dev->can.clock.freq = EMS_USB_ARM7_CLOCK;
 992         dev->can.bittiming_const = &ems_usb_bittiming_const;
 993         dev->can.do_set_bittiming = ems_usb_set_bittiming;
 994         dev->can.do_set_mode = ems_usb_set_mode;
 995         dev->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES;
 996
 997         netdev->netdev_ops = &ems_usb_netdev_ops;
 998
 999         netdev->flags |= IFF_ECHO; /* we support local echo */
1000
1001         init_usb_anchor(&dev->rx_submitted);
1002
1003         init_usb_anchor(&dev->tx_submitted);
1004         atomic_set(&dev->active_tx_urbs, 0);
1005
1006         for (i = 0; i < MAX_TX_URBS; i++)
1007                 dev->tx_contexts[i].echo_index = MAX_TX_URBS;
1008
1009         dev->intr_urb = usb_alloc_urb(0, GFP_KERNEL);
1010         if (!dev->intr_urb) {
1011                 dev_err(&intf->dev, "Couldn't alloc intr URB\n");
1012                 goto cleanup_candev;
1013         }
1014
1015         dev->intr_in_buffer = kzalloc(INTR_IN_BUFFER_SIZE, GFP_KERNEL);
1016         if (!dev->intr_in_buffer)
1017                 goto cleanup_intr_urb;
1018
1019         dev->tx_msg_buffer = kzalloc(CPC_HEADER_SIZE +
1020                                      sizeof(struct ems_cpc_msg), GFP_KERNEL);
1021         if (!dev->tx_msg_buffer)
1022                 goto cleanup_intr_in_buffer;
1023
1024         usb_set_intfdata(intf, dev);
1025
1026         SET_NETDEV_DEV(netdev, &intf->dev);
1027
1028         init_params_sja1000(&dev->active_params);
1029
1030         err = ems_usb_command_msg(dev, &dev->active_params);
1031         if (err) {
1032                 netdev_err(netdev, "couldn't initialize controller: %d\n", err);
1033                 goto cleanup_tx_msg_buffer;
1034         }
1035
1036         err = register_candev(netdev);
1037         if (err) {
1038                 netdev_err(netdev, "couldn't register CAN device: %d\n", err);
1039                 goto cleanup_tx_msg_buffer;
1040         }
1041
1042         return 0;
1043
1044 cleanup_tx_msg_buffer:
1045         kfree(dev->tx_msg_buffer);
1046
1047 cleanup_intr_in_buffer:
1048         kfree(dev->intr_in_buffer);
1049
1050 cleanup_intr_urb:
1051         usb_free_urb(dev->intr_urb);
1052
1053 cleanup_candev:
1054         free_candev(netdev);
1055
1056         return err;
1057 }
1058
1059 /*
1060  * called by the usb core when the device is removed from the system
1061  */
1062 static void ems_usb_disconnect(struct usb_interface *intf)
1063 {
1064         struct ems_usb *dev = usb_get_intfdata(intf);
1065
1066         usb_set_intfdata(intf, NULL);
1067
1068         if (dev) {
1069                 unregister_netdev(dev->netdev);
1070                 free_candev(dev->netdev);
1071
1072                 unlink_all_urbs(dev);
1073
1074                 usb_free_urb(dev->intr_urb);
1075
1076                 kfree(dev->intr_in_buffer);
1077         }
1078 }
1079
1080 /* usb specific object needed to register this driver with the usb subsystem */
1081 static struct usb_driver ems_usb_driver = {
1082         .name = "ems_usb",
1083         .probe = ems_usb_probe,
1084         .disconnect = ems_usb_disconnect,
1085         .id_table = ems_usb_table,
1086 };
1087
1088 module_usb_driver(ems_usb_driver);