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 #define CPC_TX_QUEUE_TRIGGER_LOW        25
 122 #define CPC_TX_QUEUE_TRIGGER_HIGH       35
 123
 124 /*
 125  * CAN-Message representation in a CPC_MSG. Message object type is
 126  * CPC_MSG_TYPE_CAN_FRAME or CPC_MSG_TYPE_RTR_FRAME or
 127  * CPC_MSG_TYPE_EXT_CAN_FRAME or CPC_MSG_TYPE_EXT_RTR_FRAME.
 128  */
 129 struct cpc_can_msg {
 130         u32 id;
 131         u8 length;
 132         u8 msg[8];
 133 };
 134
 135 /* Representation of the CAN parameters for the SJA1000 controller */
 136 struct cpc_sja1000_params {
 137         u8 mode;
 138         u8 acc_code0;
 139         u8 acc_code1;
 140         u8 acc_code2;
 141         u8 acc_code3;
 142         u8 acc_mask0;
 143         u8 acc_mask1;
 144         u8 acc_mask2;
 145         u8 acc_mask3;
 146         u8 btr0;
 147         u8 btr1;
 148         u8 outp_contr;
 149 };
 150
 151 /* CAN params message representation */
 152 struct cpc_can_params {
 153         u8 cc_type;
 154
 155         /* Will support M16C CAN controller in the future */
 156         union {
 157                 struct cpc_sja1000_params sja1000;
 158         } cc_params;
 159 };
 160
 161 /* Structure for confirmed message handling */
 162 struct cpc_confirm {
 163         u8 error; /* error code */
 164 };
 165
 166 /* Structure for overrun conditions */
 167 struct cpc_overrun {
 168         u8 event;
 169         u8 count;
 170 };
 171
 172 /* SJA1000 CAN errors (compatible to NXP LPC2119) */
 173 struct cpc_sja1000_can_error {
 174         u8 ecc;
 175         u8 rxerr;
 176         u8 txerr;
 177 };
 178
 179 /* structure for CAN error conditions */
 180 struct cpc_can_error {
 181         u8 ecode;
 182
 183         struct {
 184                 u8 cc_type;
 185
 186                 /* Other controllers may also provide error code capture regs */
 187                 union {
 188                         struct cpc_sja1000_can_error sja1000;
 189                 } regs;
 190         } cc;
 191 };
 192
 193 /*
 194  * Structure containing RX/TX error counter. This structure is used to request
 195  * the values of the CAN controllers TX and RX error counter.
 196  */
 197 struct cpc_can_err_counter {
 198         u8 rx;
 199         u8 tx;
 200 };
 201
 202 /* Main message type used between library and application */
 203 struct __packed ems_cpc_msg {
 204         u8 type;        /* type of message */
 205         u8 length;      /* length of data within union 'msg' */
 206         u8 msgid;       /* confirmation handle */
 207         u32 ts_sec;     /* timestamp in seconds */
 208         u32 ts_nsec;    /* timestamp in nano seconds */
 209
 210         union {
 211                 u8 generic[64];
 212                 struct cpc_can_msg can_msg;
 213                 struct cpc_can_params can_params;
 214                 struct cpc_confirm confirmation;
 215                 struct cpc_overrun overrun;
 216                 struct cpc_can_error error;
 217                 struct cpc_can_err_counter err_counter;
 218                 u8 can_state;
 219         } msg;
 220 };
 221
 222 /*
 223  * Table of devices that work with this driver
 224  * NOTE: This driver supports only CPC-USB/ARM7 (LPC2119) yet.
 225  */
 226 static struct usb_device_id ems_usb_table[] = {
 227         {USB_DEVICE(USB_CPCUSB_VENDOR_ID, USB_CPCUSB_ARM7_PRODUCT_ID)},
 228         {} /* Terminating entry */
 229 };
 230
 231 MODULE_DEVICE_TABLE(usb, ems_usb_table);
 232
 233 #define RX_BUFFER_SIZE      64
 234 #define CPC_HEADER_SIZE     4
 235 #define INTR_IN_BUFFER_SIZE 4
 236
 237 #define MAX_RX_URBS 10
 238 #define MAX_TX_URBS 10
 239
 240 struct ems_usb;
 241
 242 struct ems_tx_urb_context {
 243         struct ems_usb *dev;
 244
 245         u32 echo_index;
 246         u8 dlc;
 247 };
 248
 249 struct ems_usb {
 250         struct can_priv can; /* must be the first member */
 251         int open_time;
 252
 253         struct sk_buff *echo_skb[MAX_TX_URBS];
 254
 255         struct usb_device *udev;
 256         struct net_device *netdev;
 257
 258         atomic_t active_tx_urbs;
 259         struct usb_anchor tx_submitted;
 260         struct ems_tx_urb_context tx_contexts[MAX_TX_URBS];
 261
 262         struct usb_anchor rx_submitted;
 263
 264         struct urb *intr_urb;
 265
 266         u8 *tx_msg_buffer;
 267
 268         u8 *intr_in_buffer;
 269         unsigned int free_slots; /* remember number of available slots */
 270
 271         struct ems_cpc_msg active_params; /* active controller parameters */
 272 };
 273
 274 static void ems_usb_read_interrupt_callback(struct urb *urb)
 275 {
 276         struct ems_usb *dev = urb->context;
 277         struct net_device *netdev = dev->netdev;
 278         int err;
 279
 280         if (!netif_device_present(netdev))
 281                 return;
 282
 283         switch (urb->status) {
 284         case 0:
 285                 dev->free_slots = dev->intr_in_buffer[1];
 286                 if(dev->free_slots > CPC_TX_QUEUE_TRIGGER_HIGH){
 287                         if (netif_queue_stopped(netdev)){
 288                                 netif_wake_queue(netdev);
 289                         }
 290                 }
 291                 break;
 292
 293         case -ECONNRESET: /* unlink */
 294         case -ENOENT:
 295         case -ESHUTDOWN:
 296                 return;
 297
 298         default:
 299                 dev_info(netdev->dev.parent, "Rx interrupt aborted %d\n",
 300                          urb->status);
 301                 break;
 302         }
 303
 304         err = usb_submit_urb(urb, GFP_ATOMIC);
 305
 306         if (err == -ENODEV)
 307                 netif_device_detach(netdev);
 308         else if (err)
 309                 dev_err(netdev->dev.parent,
 310                         "failed resubmitting intr urb: %d\n", err);
 311 }
 312
 313 static void ems_usb_rx_can_msg(struct ems_usb *dev, struct ems_cpc_msg *msg)
 314 {
 315         struct can_frame *cf;
 316         struct sk_buff *skb;
 317         int i;
 318         struct net_device_stats *stats = &dev->netdev->stats;
 319
 320         skb = alloc_can_skb(dev->netdev, &cf);
 321         if (skb == NULL)
 322                 return;
 323
 324         cf->can_id = le32_to_cpu(msg->msg.can_msg.id);
 325         cf->can_dlc = get_can_dlc(msg->msg.can_msg.length & 0xF);
 326
 327         if (msg->type == CPC_MSG_TYPE_EXT_CAN_FRAME ||
 328             msg->type == CPC_MSG_TYPE_EXT_RTR_FRAME)
 329                 cf->can_id |= CAN_EFF_FLAG;
 330
 331         if (msg->type == CPC_MSG_TYPE_RTR_FRAME ||
 332             msg->type == CPC_MSG_TYPE_EXT_RTR_FRAME) {
 333                 cf->can_id |= CAN_RTR_FLAG;
 334         } else {
 335                 for (i = 0; i < cf->can_dlc; i++)
 336                         cf->data[i] = msg->msg.can_msg.msg[i];
 337         }
 338
 339         netif_rx(skb);
 340
 341         stats->rx_packets++;
 342         stats->rx_bytes += cf->can_dlc;
 343 }
 344
 345 static void ems_usb_rx_err(struct ems_usb *dev, struct ems_cpc_msg *msg)
 346 {
 347         struct can_frame *cf;
 348         struct sk_buff *skb;
 349         struct net_device_stats *stats = &dev->netdev->stats;
 350
 351         skb = alloc_can_err_skb(dev->netdev, &cf);
 352         if (skb == NULL)
 353                 return;
 354
 355         if (msg->type == CPC_MSG_TYPE_CAN_STATE) {
 356                 u8 state = msg->msg.can_state;
 357
 358                 if (state & SJA1000_SR_BS) {
 359                         dev->can.state = CAN_STATE_BUS_OFF;
 360                         cf->can_id |= CAN_ERR_BUSOFF;
 361
 362                         can_bus_off(dev->netdev);
 363                 } else if (state & SJA1000_SR_ES) {
 364                         dev->can.state = CAN_STATE_ERROR_WARNING;
 365                         dev->can.can_stats.error_warning++;
 366                 } else {
 367                         dev->can.state = CAN_STATE_ERROR_ACTIVE;
 368                         dev->can.can_stats.error_passive++;
 369                 }
 370         } else if (msg->type == CPC_MSG_TYPE_CAN_FRAME_ERROR) {
 371                 u8 ecc = msg->msg.error.cc.regs.sja1000.ecc;
 372                 u8 txerr = msg->msg.error.cc.regs.sja1000.txerr;
 373                 u8 rxerr = msg->msg.error.cc.regs.sja1000.rxerr;
 374
 375                 /* bus error interrupt */
 376                 dev->can.can_stats.bus_error++;
 377                 stats->rx_errors++;
 378
 379                 cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
 380
 381                 switch (ecc & SJA1000_ECC_MASK) {
 382                 case SJA1000_ECC_BIT:
 383                         cf->data[2] |= CAN_ERR_PROT_BIT;
 384                         break;
 385                 case SJA1000_ECC_FORM:
 386                         cf->data[2] |= CAN_ERR_PROT_FORM;
 387                         break;
 388                 case SJA1000_ECC_STUFF:
 389                         cf->data[2] |= CAN_ERR_PROT_STUFF;
 390                         break;
 391                 default:
 392                         cf->data[2] |= CAN_ERR_PROT_UNSPEC;
 393                         cf->data[3] = ecc & SJA1000_ECC_SEG;
 394                         break;
 395                 }
 396
 397                 /* Error occurred during transmission? */
 398                 if ((ecc & SJA1000_ECC_DIR) == 0)
 399                         cf->data[2] |= CAN_ERR_PROT_TX;
 400
 401                 if (dev->can.state == CAN_STATE_ERROR_WARNING ||
 402                     dev->can.state == CAN_STATE_ERROR_PASSIVE) {
 403                         cf->data[1] = (txerr > rxerr) ?
 404                             CAN_ERR_CRTL_TX_PASSIVE : CAN_ERR_CRTL_RX_PASSIVE;
 405                 }
 406         } else if (msg->type == CPC_MSG_TYPE_OVERRUN) {
 407                 cf->can_id |= CAN_ERR_CRTL;
 408                 cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
 409
 410                 stats->rx_over_errors++;
 411                 stats->rx_errors++;
 412         }
 413
 414         netif_rx(skb);
 415
 416         stats->rx_packets++;
 417         stats->rx_bytes += cf->can_dlc;
 418 }
 419
 420 /*
 421  * callback for bulk IN urb
 422  */
 423 static void ems_usb_read_bulk_callback(struct urb *urb)
 424 {
 425         struct ems_usb *dev = urb->context;
 426         struct net_device *netdev;
 427         int retval;
 428
 429         netdev = dev->netdev;
 430
 431         if (!netif_device_present(netdev))
 432                 return;
 433
 434         switch (urb->status) {
 435         case 0: /* success */
 436                 break;
 437
 438         case -ENOENT:
 439                 return;
 440
 441         default:
 442                 dev_info(netdev->dev.parent, "Rx URB aborted (%d)\n",
 443                          urb->status);
 444                 goto resubmit_urb;
 445         }
 446
 447         if (urb->actual_length > CPC_HEADER_SIZE) {
 448                 struct ems_cpc_msg *msg;
 449                 u8 *ibuf = urb->transfer_buffer;
 450                 u8 msg_count, again, start;
 451
 452                 msg_count = ibuf[0] & ~0x80;
 453                 again = ibuf[0] & 0x80;
 454
 455                 start = CPC_HEADER_SIZE;
 456
 457                 while (msg_count) {
 458                         msg = (struct ems_cpc_msg *)&ibuf[start];
 459
 460                         switch (msg->type) {
 461                         case CPC_MSG_TYPE_CAN_STATE:
 462                                 /* Process CAN state changes */
 463                                 ems_usb_rx_err(dev, msg);
 464                                 break;
 465
 466                         case CPC_MSG_TYPE_CAN_FRAME:
 467                         case CPC_MSG_TYPE_EXT_CAN_FRAME:
 468                         case CPC_MSG_TYPE_RTR_FRAME:
 469                         case CPC_MSG_TYPE_EXT_RTR_FRAME:
 470                                 ems_usb_rx_can_msg(dev, msg);
 471                                 break;
 472
 473                         case CPC_MSG_TYPE_CAN_FRAME_ERROR:
 474                                 /* Process errorframe */
 475                                 ems_usb_rx_err(dev, msg);
 476                                 break;
 477
 478                         case CPC_MSG_TYPE_OVERRUN:
 479                                 /* Message lost while receiving */
 480                                 ems_usb_rx_err(dev, msg);
 481                                 break;
 482                         }
 483
 484                         start += CPC_MSG_HEADER_LEN + msg->length;
 485                         msg_count--;
 486
 487                         if (start > urb->transfer_buffer_length) {
 488                                 dev_err(netdev->dev.parent, "format error\n");
 489                                 break;
 490                         }
 491                 }
 492         }
 493
 494 resubmit_urb:
 495         usb_fill_bulk_urb(urb, dev->udev, usb_rcvbulkpipe(dev->udev, 2),
 496                           urb->transfer_buffer, RX_BUFFER_SIZE,
 497                           ems_usb_read_bulk_callback, dev);
 498
 499         retval = usb_submit_urb(urb, GFP_ATOMIC);
 500
 501         if (retval == -ENODEV)
 502                 netif_device_detach(netdev);
 503         else if (retval)
 504                 dev_err(netdev->dev.parent,
 505                         "failed resubmitting read bulk urb: %d\n", retval);
 506 }
 507
 508 /*
 509  * callback for bulk IN urb
 510  */
 511 static void ems_usb_write_bulk_callback(struct urb *urb)
 512 {
 513         struct ems_tx_urb_context *context = urb->context;
 514         struct ems_usb *dev;
 515         struct net_device *netdev;
 516
 517         BUG_ON(!context);
 518
 519         dev = context->dev;
 520         netdev = dev->netdev;
 521
 522         /* free up our allocated buffer */
 523         usb_free_coherent(urb->dev, urb->transfer_buffer_length,
 524                           urb->transfer_buffer, urb->transfer_dma);
 525
 526         atomic_dec(&dev->active_tx_urbs);
 527
 528         if (!netif_device_present(netdev))
 529                 return;
 530
 531         if (urb->status)
 532                 dev_info(netdev->dev.parent, "Tx URB aborted (%d)\n",
 533                          urb->status);
 534
 535         netdev->trans_start = jiffies;
 536
 537         /* transmission complete interrupt */
 538         netdev->stats.tx_packets++;
 539         netdev->stats.tx_bytes += context->dlc;
 540
 541         can_get_echo_skb(netdev, context->echo_index);
 542
 543         /* Release context */
 544         context->echo_index = MAX_TX_URBS;
 545
 546 }
 547
 548 /*
 549  * Send the given CPC command synchronously
 550  */
 551 static int ems_usb_command_msg(struct ems_usb *dev, struct ems_cpc_msg *msg)
 552 {
 553         int actual_length;
 554
 555         /* Copy payload */
 556         memcpy(&dev->tx_msg_buffer[CPC_HEADER_SIZE], msg,
 557                msg->length + CPC_MSG_HEADER_LEN);
 558
 559         /* Clear header */
 560         memset(&dev->tx_msg_buffer[0], 0, CPC_HEADER_SIZE);
 561
 562         return usb_bulk_msg(dev->udev, usb_sndbulkpipe(dev->udev, 2),
 563                             &dev->tx_msg_buffer[0],
 564                             msg->length + CPC_MSG_HEADER_LEN + CPC_HEADER_SIZE,
 565                             &actual_length, 1000);
 566 }
 567
 568 /*
 569  * Change CAN controllers' mode register
 570  */
 571 static int ems_usb_write_mode(struct ems_usb *dev, u8 mode)
 572 {
 573         dev->active_params.msg.can_params.cc_params.sja1000.mode = mode;
 574
 575         return ems_usb_command_msg(dev, &dev->active_params);
 576 }
 577
 578 /*
 579  * Send a CPC_Control command to change behaviour when interface receives a CAN
 580  * message, bus error or CAN state changed notifications.
 581  */
 582 static int ems_usb_control_cmd(struct ems_usb *dev, u8 val)
 583 {
 584         struct ems_cpc_msg cmd;
 585
 586         cmd.type = CPC_CMD_TYPE_CONTROL;
 587         cmd.length = CPC_MSG_HEADER_LEN + 1;
 588
 589         cmd.msgid = 0;
 590
 591         cmd.msg.generic[0] = val;
 592
 593         return ems_usb_command_msg(dev, &cmd);
 594 }
 595
 596 /*
 597  * Start interface
 598  */
 599 static int ems_usb_start(struct ems_usb *dev)
 600 {
 601         struct net_device *netdev = dev->netdev;
 602         int err, i;
 603
 604         dev->intr_in_buffer[0] = 0;
 605         dev->free_slots = 50; /* initial size */
 606
 607         for (i = 0; i < MAX_RX_URBS; i++) {
 608                 struct urb *urb = NULL;
 609                 u8 *buf = NULL;
 610
 611                 /* create a URB, and a buffer for it */
 612                 urb = usb_alloc_urb(0, GFP_KERNEL);
 613                 if (!urb) {
 614                         dev_err(netdev->dev.parent,
 615                                 "No memory left for URBs\n");
 616                         return -ENOMEM;
 617                 }
 618
 619                 buf = usb_alloc_coherent(dev->udev, RX_BUFFER_SIZE, GFP_KERNEL,
 620                                          &urb->transfer_dma);
 621                 if (!buf) {
 622                         dev_err(netdev->dev.parent,
 623                                 "No memory left for USB buffer\n");
 624                         usb_free_urb(urb);
 625                         return -ENOMEM;
 626                 }
 627
 628                 usb_fill_bulk_urb(urb, dev->udev, usb_rcvbulkpipe(dev->udev, 2),
 629                                   buf, RX_BUFFER_SIZE,
 630                                   ems_usb_read_bulk_callback, dev);
 631                 urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 632                 usb_anchor_urb(urb, &dev->rx_submitted);
 633
 634                 err = usb_submit_urb(urb, GFP_KERNEL);
 635                 if (err) {
 636                         if (err == -ENODEV)
 637                                 netif_device_detach(dev->netdev);
 638
 639                         usb_unanchor_urb(urb);
 640                         usb_free_coherent(dev->udev, RX_BUFFER_SIZE, buf,
 641                                           urb->transfer_dma);
 642                         break;
 643                 }
 644
 645                 /* Drop reference, USB core will take care of freeing it */
 646                 usb_free_urb(urb);
 647         }
 648
 649         /* Did we submit any URBs */
 650         if (i == 0) {
 651                 dev_warn(netdev->dev.parent, "couldn't setup read URBs\n");
 652                 return err;
 653         }
 654
 655         /* Warn if we've couldn't transmit all the URBs */
 656         if (i < MAX_RX_URBS)
 657                 dev_warn(netdev->dev.parent, "rx performance may be slow\n");
 658
 659         /* Setup and start interrupt URB */
 660         usb_fill_int_urb(dev->intr_urb, dev->udev,
 661                          usb_rcvintpipe(dev->udev, 1),
 662                          dev->intr_in_buffer,
 663                          INTR_IN_BUFFER_SIZE,
 664                          ems_usb_read_interrupt_callback, dev, 1);
 665
 666         err = usb_submit_urb(dev->intr_urb, GFP_KERNEL);
 667         if (err) {
 668                 if (err == -ENODEV)
 669                         netif_device_detach(dev->netdev);
 670
 671                 dev_warn(netdev->dev.parent, "intr URB submit failed: %d\n",
 672                          err);
 673
 674                 return err;
 675         }
 676
 677         /* CPC-USB will transfer received message to host */
 678         err = ems_usb_control_cmd(dev, CONTR_CAN_MESSAGE | CONTR_CONT_ON);
 679         if (err)
 680                 goto failed;
 681
 682         /* CPC-USB will transfer CAN state changes to host */
 683         err = ems_usb_control_cmd(dev, CONTR_CAN_STATE | CONTR_CONT_ON);
 684         if (err)
 685                 goto failed;
 686
 687         /* CPC-USB will transfer bus errors to host */
 688         err = ems_usb_control_cmd(dev, CONTR_BUS_ERROR | CONTR_CONT_ON);
 689         if (err)
 690                 goto failed;
 691
 692         err = ems_usb_write_mode(dev, SJA1000_MOD_NORMAL);
 693         if (err)
 694                 goto failed;
 695
 696         dev->can.state = CAN_STATE_ERROR_ACTIVE;
 697
 698         return 0;
 699
 700 failed:
 701         if (err == -ENODEV)
 702                 netif_device_detach(dev->netdev);
 703
 704         dev_warn(netdev->dev.parent, "couldn't submit control: %d\n", err);
 705
 706         return err;
 707 }
 708
 709 static void unlink_all_urbs(struct ems_usb *dev)
 710 {
 711         int i;
 712
 713         usb_unlink_urb(dev->intr_urb);
 714
 715         usb_kill_anchored_urbs(&dev->rx_submitted);
 716
 717         usb_kill_anchored_urbs(&dev->tx_submitted);
 718         atomic_set(&dev->active_tx_urbs, 0);
 719
 720         for (i = 0; i < MAX_TX_URBS; i++)
 721                 dev->tx_contexts[i].echo_index = MAX_TX_URBS;
 722 }
 723
 724 static int ems_usb_open(struct net_device *netdev)
 725 {
 726         struct ems_usb *dev = netdev_priv(netdev);
 727         int err;
 728
 729         err = ems_usb_write_mode(dev, SJA1000_MOD_RM);
 730         if (err)
 731                 return err;
 732
 733         /* common open */
 734         err = open_candev(netdev);
 735         if (err)
 736                 return err;
 737
 738         /* finally start device */
 739         err = ems_usb_start(dev);
 740         if (err) {
 741                 if (err == -ENODEV)
 742                         netif_device_detach(dev->netdev);
 743
 744                 dev_warn(netdev->dev.parent, "couldn't start device: %d\n",
 745                          err);
 746
 747                 close_candev(netdev);
 748
 749                 return err;
 750         }
 751
 752         dev->open_time = jiffies;
 753
 754         netif_start_queue(netdev);
 755
 756         return 0;
 757 }
 758
 759 static netdev_tx_t ems_usb_start_xmit(struct sk_buff *skb, struct net_device *netdev)
 760 {
 761         struct ems_usb *dev = netdev_priv(netdev);
 762         struct ems_tx_urb_context *context = NULL;
 763         struct net_device_stats *stats = &netdev->stats;
 764         struct can_frame *cf = (struct can_frame *)skb->data;
 765         struct ems_cpc_msg *msg;
 766         struct urb *urb;
 767         u8 *buf;
 768         int i, err;
 769         size_t size = CPC_HEADER_SIZE + CPC_MSG_HEADER_LEN
 770                         + sizeof(struct cpc_can_msg);
 771
 772         if (can_dropped_invalid_skb(netdev, skb))
 773                 return NETDEV_TX_OK;
 774
 775         /* create a URB, and a buffer for it, and copy the data to the URB */
 776         urb = usb_alloc_urb(0, GFP_ATOMIC);
 777         if (!urb) {
 778                 dev_err(netdev->dev.parent, "No memory left for URBs\n");
 779                 goto nomem;
 780         }
 781
 782         buf = usb_alloc_coherent(dev->udev, size, GFP_ATOMIC, &urb->transfer_dma);
 783         if (!buf) {
 784                 dev_err(netdev->dev.parent, "No memory left for USB buffer\n");
 785                 usb_free_urb(urb);
 786                 goto nomem;
 787         }
 788
 789         msg = (struct ems_cpc_msg *)&buf[CPC_HEADER_SIZE];
 790
 791         msg->msg.can_msg.id = cf->can_id & CAN_ERR_MASK;
 792         msg->msg.can_msg.length = cf->can_dlc;
 793
 794         if (cf->can_id & CAN_RTR_FLAG) {
 795                 msg->type = cf->can_id & CAN_EFF_FLAG ?
 796                         CPC_CMD_TYPE_EXT_RTR_FRAME : CPC_CMD_TYPE_RTR_FRAME;
 797
 798                 msg->length = CPC_CAN_MSG_MIN_SIZE;
 799         } else {
 800                 msg->type = cf->can_id & CAN_EFF_FLAG ?
 801                         CPC_CMD_TYPE_EXT_CAN_FRAME : CPC_CMD_TYPE_CAN_FRAME;
 802
 803                 for (i = 0; i < cf->can_dlc; i++)
 804                         msg->msg.can_msg.msg[i] = cf->data[i];
 805
 806                 msg->length = CPC_CAN_MSG_MIN_SIZE + cf->can_dlc;
 807         }
 808
 809         /* Respect byte order */
 810         msg->msg.can_msg.id = cpu_to_le32(msg->msg.can_msg.id);
 811
 812         for (i = 0; i < MAX_TX_URBS; i++) {
 813                 if (dev->tx_contexts[i].echo_index == MAX_TX_URBS) {
 814                         context = &dev->tx_contexts[i];
 815                         break;
 816                 }
 817         }
 818
 819         /*
 820          * May never happen! When this happens we'd more URBs in flight as
 821          * allowed (MAX_TX_URBS).
 822          */
 823         if (!context) {
 824                 usb_unanchor_urb(urb);
 825                 usb_free_coherent(dev->udev, size, buf, urb->transfer_dma);
 826
 827                 dev_warn(netdev->dev.parent, "couldn't find free context\n");
 828
 829                 return NETDEV_TX_BUSY;
 830         }
 831
 832         context->dev = dev;
 833         context->echo_index = i;
 834         context->dlc = cf->can_dlc;
 835
 836         usb_fill_bulk_urb(urb, dev->udev, usb_sndbulkpipe(dev->udev, 2), buf,
 837                           size, ems_usb_write_bulk_callback, context);
 838         urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 839         usb_anchor_urb(urb, &dev->tx_submitted);
 840
 841         can_put_echo_skb(skb, netdev, context->echo_index);
 842
 843         atomic_inc(&dev->active_tx_urbs);
 844
 845         err = usb_submit_urb(urb, GFP_ATOMIC);
 846         if (unlikely(err)) {
 847                 can_free_echo_skb(netdev, context->echo_index);
 848
 849                 usb_unanchor_urb(urb);
 850                 usb_free_coherent(dev->udev, size, buf, urb->transfer_dma);
 851                 dev_kfree_skb(skb);
 852
 853                 atomic_dec(&dev->active_tx_urbs);
 854
 855                 if (err == -ENODEV) {
 856                         netif_device_detach(netdev);
 857                 } else {
 858                         dev_warn(netdev->dev.parent, "failed tx_urb %d\n", err);
 859
 860                         stats->tx_dropped++;
 861                 }
 862         } else {
 863                 netdev->trans_start = jiffies;
 864
 865                 /* Slow down tx path */
 866                 if (atomic_read(&dev->active_tx_urbs) >= MAX_TX_URBS ||
 867                     dev->free_slots < CPC_TX_QUEUE_TRIGGER_LOW) {
 868                         netif_stop_queue(netdev);
 869                 }
 870         }
 871
 872         /*
 873          * Release our reference to this URB, the USB core will eventually free
 874          * it entirely.
 875          */
 876         usb_free_urb(urb);
 877
 878         return NETDEV_TX_OK;
 879
 880 nomem:
 881         dev_kfree_skb(skb);
 882         stats->tx_dropped++;
 883
 884         return NETDEV_TX_OK;
 885 }
 886
 887 static int ems_usb_close(struct net_device *netdev)
 888 {
 889         struct ems_usb *dev = netdev_priv(netdev);
 890
 891         /* Stop polling */
 892         unlink_all_urbs(dev);
 893
 894         netif_stop_queue(netdev);
 895
 896         /* Set CAN controller to reset mode */
 897         if (ems_usb_write_mode(dev, SJA1000_MOD_RM))
 898                 dev_warn(netdev->dev.parent, "couldn't stop device");
 899
 900         close_candev(netdev);
 901
 902         dev->open_time = 0;
 903
 904         return 0;
 905 }
 906
 907 static const struct net_device_ops ems_usb_netdev_ops = {
 908         .ndo_open = ems_usb_open,
 909         .ndo_stop = ems_usb_close,
 910         .ndo_start_xmit = ems_usb_start_xmit,
 911 };
 912
 913 static struct can_bittiming_const ems_usb_bittiming_const = {
 914         .name = "ems_usb",
 915         .tseg1_min = 1,
 916         .tseg1_max = 16,
 917         .tseg2_min = 1,
 918         .tseg2_max = 8,
 919         .sjw_max = 4,
 920         .brp_min = 1,
 921         .brp_max = 64,
 922         .brp_inc = 1,
 923 };
 924
 925 static int ems_usb_set_mode(struct net_device *netdev, enum can_mode mode)
 926 {
 927         struct ems_usb *dev = netdev_priv(netdev);
 928
 929         if (!dev->open_time)
 930                 return -EINVAL;
 931
 932         switch (mode) {
 933         case CAN_MODE_START:
 934                 if (ems_usb_write_mode(dev, SJA1000_MOD_NORMAL))
 935                         dev_warn(netdev->dev.parent, "couldn't start device");
 936
 937                 if (netif_queue_stopped(netdev))
 938                         netif_wake_queue(netdev);
 939                 break;
 940
 941         default:
 942                 return -EOPNOTSUPP;
 943         }
 944
 945         return 0;
 946 }
 947
 948 static int ems_usb_set_bittiming(struct net_device *netdev)
 949 {
 950         struct ems_usb *dev = netdev_priv(netdev);
 951         struct can_bittiming *bt = &dev->can.bittiming;
 952         u8 btr0, btr1;
 953
 954         btr0 = ((bt->brp - 1) & 0x3f) | (((bt->sjw - 1) & 0x3) << 6);
 955         btr1 = ((bt->prop_seg + bt->phase_seg1 - 1) & 0xf) |
 956                 (((bt->phase_seg2 - 1) & 0x7) << 4);
 957         if (dev->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES)
 958                 btr1 |= 0x80;
 959
 960         dev_info(netdev->dev.parent, "setting BTR0=0x%02x BTR1=0x%02x\n",
 961                  btr0, btr1);
 962
 963         dev->active_params.msg.can_params.cc_params.sja1000.btr0 = btr0;
 964         dev->active_params.msg.can_params.cc_params.sja1000.btr1 = btr1;
 965
 966         return ems_usb_command_msg(dev, &dev->active_params);
 967 }
 968
 969 static void init_params_sja1000(struct ems_cpc_msg *msg)
 970 {
 971         struct cpc_sja1000_params *sja1000 =
 972                 &msg->msg.can_params.cc_params.sja1000;
 973
 974         msg->type = CPC_CMD_TYPE_CAN_PARAMS;
 975         msg->length = sizeof(struct cpc_can_params);
 976         msg->msgid = 0;
 977
 978         msg->msg.can_params.cc_type = CPC_CC_TYPE_SJA1000;
 979
 980         /* Acceptance filter open */
 981         sja1000->acc_code0 = 0x00;
 982         sja1000->acc_code1 = 0x00;
 983         sja1000->acc_code2 = 0x00;
 984         sja1000->acc_code3 = 0x00;
 985
 986         /* Acceptance filter open */
 987         sja1000->acc_mask0 = 0xFF;
 988         sja1000->acc_mask1 = 0xFF;
 989         sja1000->acc_mask2 = 0xFF;
 990         sja1000->acc_mask3 = 0xFF;
 991
 992         sja1000->btr0 = 0;
 993         sja1000->btr1 = 0;
 994
 995         sja1000->outp_contr = SJA1000_DEFAULT_OUTPUT_CONTROL;
 996         sja1000->mode = SJA1000_MOD_RM;
 997 }
 998
 999 /*
1000  * probe function for new CPC-USB devices
1001  */
1002 static int ems_usb_probe(struct usb_interface *intf,
1003                          const struct usb_device_id *id)
1004 {
1005         struct net_device *netdev;
1006         struct ems_usb *dev;
1007         int i, err = -ENOMEM;
1008
1009         netdev = alloc_candev(sizeof(struct ems_usb), MAX_TX_URBS);
1010         if (!netdev) {
1011                 dev_err(&intf->dev, "ems_usb: Couldn't alloc candev\n");
1012                 return -ENOMEM;
1013         }
1014
1015         dev = netdev_priv(netdev);
1016
1017         dev->udev = interface_to_usbdev(intf);
1018         dev->netdev = netdev;
1019
1020         dev->can.state = CAN_STATE_STOPPED;
1021         dev->can.clock.freq = EMS_USB_ARM7_CLOCK;
1022         dev->can.bittiming_const = &ems_usb_bittiming_const;
1023         dev->can.do_set_bittiming = ems_usb_set_bittiming;
1024         dev->can.do_set_mode = ems_usb_set_mode;
1025         dev->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES;
1026
1027         netdev->netdev_ops = &ems_usb_netdev_ops;
1028
1029         netdev->flags |= IFF_ECHO; /* we support local echo */
1030
1031         init_usb_anchor(&dev->rx_submitted);
1032
1033         init_usb_anchor(&dev->tx_submitted);
1034         atomic_set(&dev->active_tx_urbs, 0);
1035
1036         for (i = 0; i < MAX_TX_URBS; i++)
1037                 dev->tx_contexts[i].echo_index = MAX_TX_URBS;
1038
1039         dev->intr_urb = usb_alloc_urb(0, GFP_KERNEL);
1040         if (!dev->intr_urb) {
1041                 dev_err(&intf->dev, "Couldn't alloc intr URB\n");
1042                 goto cleanup_candev;
1043         }
1044
1045         dev->intr_in_buffer = kzalloc(INTR_IN_BUFFER_SIZE, GFP_KERNEL);
1046         if (!dev->intr_in_buffer) {
1047                 dev_err(&intf->dev, "Couldn't alloc Intr buffer\n");
1048                 goto cleanup_intr_urb;
1049         }
1050
1051         dev->tx_msg_buffer = kzalloc(CPC_HEADER_SIZE +
1052                                      sizeof(struct ems_cpc_msg), GFP_KERNEL);
1053         if (!dev->tx_msg_buffer) {
1054                 dev_err(&intf->dev, "Couldn't alloc Tx buffer\n");
1055                 goto cleanup_intr_in_buffer;
1056         }
1057
1058         usb_set_intfdata(intf, dev);
1059
1060         SET_NETDEV_DEV(netdev, &intf->dev);
1061
1062         init_params_sja1000(&dev->active_params);
1063
1064         err = ems_usb_command_msg(dev, &dev->active_params);
1065         if (err) {
1066                 dev_err(netdev->dev.parent,
1067                         "couldn't initialize controller: %d\n", err);
1068                 goto cleanup_tx_msg_buffer;
1069         }
1070
1071         err = register_candev(netdev);
1072         if (err) {
1073                 dev_err(netdev->dev.parent,
1074                         "couldn't register CAN device: %d\n", err);
1075                 goto cleanup_tx_msg_buffer;
1076         }
1077
1078         return 0;
1079
1080 cleanup_tx_msg_buffer:
1081         kfree(dev->tx_msg_buffer);
1082
1083 cleanup_intr_in_buffer:
1084         kfree(dev->intr_in_buffer);
1085
1086 cleanup_intr_urb:
1087         usb_free_urb(dev->intr_urb);
1088
1089 cleanup_candev:
1090         free_candev(netdev);
1091
1092         return err;
1093 }
1094
1095 /*
1096  * called by the usb core when the device is removed from the system
1097  */
1098 static void ems_usb_disconnect(struct usb_interface *intf)
1099 {
1100         struct ems_usb *dev = usb_get_intfdata(intf);
1101
1102         usb_set_intfdata(intf, NULL);
1103
1104         if (dev) {
1105                 unregister_netdev(dev->netdev);
1106                 free_candev(dev->netdev);
1107
1108                 unlink_all_urbs(dev);
1109
1110                 usb_free_urb(dev->intr_urb);
1111
1112                 kfree(dev->intr_in_buffer);
1113         }
1114 }
1115
1116 /* usb specific object needed to register this driver with the usb subsystem */
1117 static struct usb_driver ems_usb_driver = {
1118         .name = "ems_usb",
1119         .probe = ems_usb_probe,
1120         .disconnect = ems_usb_disconnect,
1121         .id_table = ems_usb_table,
1122 };
1123
1124 static int __init ems_usb_init(void)
1125 {
1126         int err;
1127
1128         printk(KERN_INFO "CPC-USB kernel driver loaded\n");
1129
1130         /* register this driver with the USB subsystem */
1131         err = usb_register(&ems_usb_driver);
1132
1133         if (err) {
1134                 err("usb_register failed. Error number %d\n", err);
1135                 return err;
1136         }
1137
1138         return 0;
1139 }
1140
1141 static void __exit ems_usb_exit(void)
1142 {
1143         /* deregister this driver with the USB subsystem */
1144         usb_deregister(&ems_usb_driver);
1145 }
1146
1147 module_init(ems_usb_init);
1148 module_exit(ems_usb_exit);