drivers/net/can/usb/ems_usb.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * CAN driver for EMS Dr. Thomas Wuensche CPC-USB/ARM7
   4  *
   5  * Copyright (C) 2004-2009 EMS Dr. Thomas Wuensche
   6  */
   7 #include <linux/signal.h>
   8 #include <linux/slab.h>
   9 #include <linux/module.h>
  10 #include <linux/netdevice.h>
  11 #include <linux/usb.h>
  12
  13 #include <linux/can.h>
  14 #include <linux/can/dev.h>
  15 #include <linux/can/error.h>
  16
  17 MODULE_AUTHOR("Sebastian Haas <haas@ems-wuensche.com>");
  18 MODULE_DESCRIPTION("CAN driver for EMS Dr. Thomas Wuensche CAN/USB interfaces");
  19 MODULE_LICENSE("GPL v2");
  20
  21 /* Control-Values for CPC_Control() Command Subject Selection */
  22 #define CONTR_CAN_MESSAGE 0x04
  23 #define CONTR_CAN_STATE   0x0C
  24 #define CONTR_BUS_ERROR   0x1C
  25
  26 /* Control Command Actions */
  27 #define CONTR_CONT_OFF 0
  28 #define CONTR_CONT_ON  1
  29 #define CONTR_ONCE     2
  30
  31 /* Messages from CPC to PC */
  32 #define CPC_MSG_TYPE_CAN_FRAME       1  /* CAN data frame */
  33 #define CPC_MSG_TYPE_RTR_FRAME       8  /* CAN remote frame */
  34 #define CPC_MSG_TYPE_CAN_PARAMS      12 /* Actual CAN parameters */
  35 #define CPC_MSG_TYPE_CAN_STATE       14 /* CAN state message */
  36 #define CPC_MSG_TYPE_EXT_CAN_FRAME   16 /* Extended CAN data frame */
  37 #define CPC_MSG_TYPE_EXT_RTR_FRAME   17 /* Extended remote frame */
  38 #define CPC_MSG_TYPE_CONTROL         19 /* change interface behavior */
  39 #define CPC_MSG_TYPE_CONFIRM         20 /* command processed confirmation */
  40 #define CPC_MSG_TYPE_OVERRUN         21 /* overrun events */
  41 #define CPC_MSG_TYPE_CAN_FRAME_ERROR 23 /* detected bus errors */
  42 #define CPC_MSG_TYPE_ERR_COUNTER     25 /* RX/TX error counter */
  43
  44 /* Messages from the PC to the CPC interface  */
  45 #define CPC_CMD_TYPE_CAN_FRAME     1   /* CAN data frame */
  46 #define CPC_CMD_TYPE_CONTROL       3   /* control of interface behavior */
  47 #define CPC_CMD_TYPE_CAN_PARAMS    6   /* set CAN parameters */
  48 #define CPC_CMD_TYPE_RTR_FRAME     13  /* CAN remote frame */
  49 #define CPC_CMD_TYPE_CAN_STATE     14  /* CAN state message */
  50 #define CPC_CMD_TYPE_EXT_CAN_FRAME 15  /* Extended CAN data frame */
  51 #define CPC_CMD_TYPE_EXT_RTR_FRAME 16  /* Extended CAN remote frame */
  52 #define CPC_CMD_TYPE_CAN_EXIT      200 /* exit the CAN */
  53
  54 #define CPC_CMD_TYPE_INQ_ERR_COUNTER 25 /* request the CAN error counters */
  55 #define CPC_CMD_TYPE_CLEAR_MSG_QUEUE 8  /* clear CPC_MSG queue */
  56 #define CPC_CMD_TYPE_CLEAR_CMD_QUEUE 28 /* clear CPC_CMD queue */
  57
  58 #define CPC_CC_TYPE_SJA1000 2 /* Philips basic CAN controller */
  59
  60 #define CPC_CAN_ECODE_ERRFRAME 0x01 /* Ecode type */
  61
  62 /* Overrun types */
  63 #define CPC_OVR_EVENT_CAN       0x01
  64 #define CPC_OVR_EVENT_CANSTATE  0x02
  65 #define CPC_OVR_EVENT_BUSERROR  0x04
  66
  67 /*
  68  * If the CAN controller lost a message we indicate it with the highest bit
  69  * set in the count field.
  70  */
  71 #define CPC_OVR_HW 0x80
  72
  73 /* Size of the "struct ems_cpc_msg" without the union */
  74 #define CPC_MSG_HEADER_LEN   11
  75 #define CPC_CAN_MSG_MIN_SIZE 5
  76
  77 /* Define these values to match your devices */
  78 #define USB_CPCUSB_VENDOR_ID 0x12D6
  79
  80 #define USB_CPCUSB_ARM7_PRODUCT_ID 0x0444
  81
  82 /* Mode register NXP LPC2119/SJA1000 CAN Controller */
  83 #define SJA1000_MOD_NORMAL 0x00
  84 #define SJA1000_MOD_RM     0x01
  85
  86 /* ECC register NXP LPC2119/SJA1000 CAN Controller */
  87 #define SJA1000_ECC_SEG   0x1F
  88 #define SJA1000_ECC_DIR   0x20
  89 #define SJA1000_ECC_ERR   0x06
  90 #define SJA1000_ECC_BIT   0x00
  91 #define SJA1000_ECC_FORM  0x40
  92 #define SJA1000_ECC_STUFF 0x80
  93 #define SJA1000_ECC_MASK  0xc0
  94
  95 /* Status register content */
  96 #define SJA1000_SR_BS 0x80
  97 #define SJA1000_SR_ES 0x40
  98
  99 #define SJA1000_DEFAULT_OUTPUT_CONTROL 0xDA
 100
 101 /*
 102  * The device actually uses a 16MHz clock to generate the CAN clock
 103  * but it expects SJA1000 bit settings based on 8MHz (is internally
 104  * converted).
 105  */
 106 #define EMS_USB_ARM7_CLOCK 8000000
 107
 108 #define CPC_TX_QUEUE_TRIGGER_LOW        25
 109 #define CPC_TX_QUEUE_TRIGGER_HIGH       35
 110
 111 /*
 112  * CAN-Message representation in a CPC_MSG. Message object type is
 113  * CPC_MSG_TYPE_CAN_FRAME or CPC_MSG_TYPE_RTR_FRAME or
 114  * CPC_MSG_TYPE_EXT_CAN_FRAME or CPC_MSG_TYPE_EXT_RTR_FRAME.
 115  */
 116 struct cpc_can_msg {
 117         __le32 id;
 118         u8 length;
 119         u8 msg[8];
 120 };
 121
 122 /* Representation of the CAN parameters for the SJA1000 controller */
 123 struct cpc_sja1000_params {
 124         u8 mode;
 125         u8 acc_code0;
 126         u8 acc_code1;
 127         u8 acc_code2;
 128         u8 acc_code3;
 129         u8 acc_mask0;
 130         u8 acc_mask1;
 131         u8 acc_mask2;
 132         u8 acc_mask3;
 133         u8 btr0;
 134         u8 btr1;
 135         u8 outp_contr;
 136 };
 137
 138 /* CAN params message representation */
 139 struct cpc_can_params {
 140         u8 cc_type;
 141
 142         /* Will support M16C CAN controller in the future */
 143         union {
 144                 struct cpc_sja1000_params sja1000;
 145         } cc_params;
 146 };
 147
 148 /* Structure for confirmed message handling */
 149 struct cpc_confirm {
 150         u8 error; /* error code */
 151 };
 152
 153 /* Structure for overrun conditions */
 154 struct cpc_overrun {
 155         u8 event;
 156         u8 count;
 157 };
 158
 159 /* SJA1000 CAN errors (compatible to NXP LPC2119) */
 160 struct cpc_sja1000_can_error {
 161         u8 ecc;
 162         u8 rxerr;
 163         u8 txerr;
 164 };
 165
 166 /* structure for CAN error conditions */
 167 struct cpc_can_error {
 168         u8 ecode;
 169
 170         struct {
 171                 u8 cc_type;
 172
 173                 /* Other controllers may also provide error code capture regs */
 174                 union {
 175                         struct cpc_sja1000_can_error sja1000;
 176                 } regs;
 177         } cc;
 178 };
 179
 180 /*
 181  * Structure containing RX/TX error counter. This structure is used to request
 182  * the values of the CAN controllers TX and RX error counter.
 183  */
 184 struct cpc_can_err_counter {
 185         u8 rx;
 186         u8 tx;
 187 };
 188
 189 /* Main message type used between library and application */
 190 struct __packed ems_cpc_msg {
 191         u8 type;        /* type of message */
 192         u8 length;      /* length of data within union 'msg' */
 193         u8 msgid;       /* confirmation handle */
 194         __le32 ts_sec;  /* timestamp in seconds */
 195         __le32 ts_nsec; /* timestamp in nano seconds */
 196
 197         union {
 198                 u8 generic[64];
 199                 struct cpc_can_msg can_msg;
 200                 struct cpc_can_params can_params;
 201                 struct cpc_confirm confirmation;
 202                 struct cpc_overrun overrun;
 203                 struct cpc_can_error error;
 204                 struct cpc_can_err_counter err_counter;
 205                 u8 can_state;
 206         } msg;
 207 };
 208
 209 /*
 210  * Table of devices that work with this driver
 211  * NOTE: This driver supports only CPC-USB/ARM7 (LPC2119) yet.
 212  */
 213 static struct usb_device_id ems_usb_table[] = {
 214         {USB_DEVICE(USB_CPCUSB_VENDOR_ID, USB_CPCUSB_ARM7_PRODUCT_ID)},
 215         {} /* Terminating entry */
 216 };
 217
 218 MODULE_DEVICE_TABLE(usb, ems_usb_table);
 219
 220 #define RX_BUFFER_SIZE      64
 221 #define CPC_HEADER_SIZE     4
 222 #define INTR_IN_BUFFER_SIZE 4
 223
 224 #define MAX_RX_URBS 10
 225 #define MAX_TX_URBS 10
 226
 227 struct ems_usb;
 228
 229 struct ems_tx_urb_context {
 230         struct ems_usb *dev;
 231
 232         u32 echo_index;
 233 };
 234
 235 struct ems_usb {
 236         struct can_priv can; /* must be the first member */
 237
 238         struct sk_buff *echo_skb[MAX_TX_URBS];
 239
 240         struct usb_device *udev;
 241         struct net_device *netdev;
 242
 243         atomic_t active_tx_urbs;
 244         struct usb_anchor tx_submitted;
 245         struct ems_tx_urb_context tx_contexts[MAX_TX_URBS];
 246
 247         struct usb_anchor rx_submitted;
 248
 249         struct urb *intr_urb;
 250
 251         u8 *tx_msg_buffer;
 252
 253         u8 *intr_in_buffer;
 254         unsigned int free_slots; /* remember number of available slots */
 255
 256         struct ems_cpc_msg active_params; /* active controller parameters */
 257         void *rxbuf[MAX_RX_URBS];
 258         dma_addr_t rxbuf_dma[MAX_RX_URBS];
 259 };
 260
 261 static void ems_usb_read_interrupt_callback(struct urb *urb)
 262 {
 263         struct ems_usb *dev = urb->context;
 264         struct net_device *netdev = dev->netdev;
 265         int err;
 266
 267         if (!netif_device_present(netdev))
 268                 return;
 269
 270         switch (urb->status) {
 271         case 0:
 272                 dev->free_slots = dev->intr_in_buffer[1];
 273                 if (dev->free_slots > CPC_TX_QUEUE_TRIGGER_HIGH &&
 274                     netif_queue_stopped(netdev))
 275                         netif_wake_queue(netdev);
 276                 break;
 277
 278         case -ECONNRESET: /* unlink */
 279         case -ENOENT:
 280         case -EPIPE:
 281         case -EPROTO:
 282         case -ESHUTDOWN:
 283                 return;
 284
 285         default:
 286                 netdev_info(netdev, "Rx interrupt aborted %d\n", urb->status);
 287                 break;
 288         }
 289
 290         err = usb_submit_urb(urb, GFP_ATOMIC);
 291
 292         if (err == -ENODEV)
 293                 netif_device_detach(netdev);
 294         else if (err)
 295                 netdev_err(netdev, "failed resubmitting intr urb: %d\n", err);
 296 }
 297
 298 static void ems_usb_rx_can_msg(struct ems_usb *dev, struct ems_cpc_msg *msg)
 299 {
 300         struct can_frame *cf;
 301         struct sk_buff *skb;
 302         int i;
 303         struct net_device_stats *stats = &dev->netdev->stats;
 304
 305         skb = alloc_can_skb(dev->netdev, &cf);
 306         if (skb == NULL)
 307                 return;
 308
 309         cf->can_id = le32_to_cpu(msg->msg.can_msg.id);
 310         cf->len = can_cc_dlc2len(msg->msg.can_msg.length & 0xF);
 311
 312         if (msg->type == CPC_MSG_TYPE_EXT_CAN_FRAME ||
 313             msg->type == CPC_MSG_TYPE_EXT_RTR_FRAME)
 314                 cf->can_id |= CAN_EFF_FLAG;
 315
 316         if (msg->type == CPC_MSG_TYPE_RTR_FRAME ||
 317             msg->type == CPC_MSG_TYPE_EXT_RTR_FRAME) {
 318                 cf->can_id |= CAN_RTR_FLAG;
 319         } else {
 320                 for (i = 0; i < cf->len; i++)
 321                         cf->data[i] = msg->msg.can_msg.msg[i];
 322
 323                 stats->rx_bytes += cf->len;
 324         }
 325         stats->rx_packets++;
 326
 327         netif_rx(skb);
 328 }
 329
 330 static void ems_usb_rx_err(struct ems_usb *dev, struct ems_cpc_msg *msg)
 331 {
 332         struct can_frame *cf;
 333         struct sk_buff *skb;
 334         struct net_device_stats *stats = &dev->netdev->stats;
 335
 336         skb = alloc_can_err_skb(dev->netdev, &cf);
 337         if (skb == NULL)
 338                 return;
 339
 340         if (msg->type == CPC_MSG_TYPE_CAN_STATE) {
 341                 u8 state = msg->msg.can_state;
 342
 343                 if (state & SJA1000_SR_BS) {
 344                         dev->can.state = CAN_STATE_BUS_OFF;
 345                         cf->can_id |= CAN_ERR_BUSOFF;
 346
 347                         dev->can.can_stats.bus_off++;
 348                         can_bus_off(dev->netdev);
 349                 } else if (state & SJA1000_SR_ES) {
 350                         dev->can.state = CAN_STATE_ERROR_WARNING;
 351                         dev->can.can_stats.error_warning++;
 352                 } else {
 353                         dev->can.state = CAN_STATE_ERROR_ACTIVE;
 354                         dev->can.can_stats.error_passive++;
 355                 }
 356         } else if (msg->type == CPC_MSG_TYPE_CAN_FRAME_ERROR) {
 357                 u8 ecc = msg->msg.error.cc.regs.sja1000.ecc;
 358                 u8 txerr = msg->msg.error.cc.regs.sja1000.txerr;
 359                 u8 rxerr = msg->msg.error.cc.regs.sja1000.rxerr;
 360
 361                 /* bus error interrupt */
 362                 dev->can.can_stats.bus_error++;
 363                 stats->rx_errors++;
 364
 365                 cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
 366
 367                 switch (ecc & SJA1000_ECC_MASK) {
 368                 case SJA1000_ECC_BIT:
 369                         cf->data[2] |= CAN_ERR_PROT_BIT;
 370                         break;
 371                 case SJA1000_ECC_FORM:
 372                         cf->data[2] |= CAN_ERR_PROT_FORM;
 373                         break;
 374                 case SJA1000_ECC_STUFF:
 375                         cf->data[2] |= CAN_ERR_PROT_STUFF;
 376                         break;
 377                 default:
 378                         cf->data[3] = ecc & SJA1000_ECC_SEG;
 379                         break;
 380                 }
 381
 382                 /* Error occurred during transmission? */
 383                 if ((ecc & SJA1000_ECC_DIR) == 0)
 384                         cf->data[2] |= CAN_ERR_PROT_TX;
 385
 386                 if (dev->can.state == CAN_STATE_ERROR_WARNING ||
 387                     dev->can.state == CAN_STATE_ERROR_PASSIVE) {
 388                         cf->can_id |= CAN_ERR_CRTL;
 389                         cf->data[1] = (txerr > rxerr) ?
 390                             CAN_ERR_CRTL_TX_PASSIVE : CAN_ERR_CRTL_RX_PASSIVE;
 391                 }
 392         } else if (msg->type == CPC_MSG_TYPE_OVERRUN) {
 393                 cf->can_id |= CAN_ERR_CRTL;
 394                 cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
 395
 396                 stats->rx_over_errors++;
 397                 stats->rx_errors++;
 398         }
 399
 400         netif_rx(skb);
 401 }
 402
 403 /*
 404  * callback for bulk IN urb
 405  */
 406 static void ems_usb_read_bulk_callback(struct urb *urb)
 407 {
 408         struct ems_usb *dev = urb->context;
 409         struct net_device *netdev;
 410         int retval;
 411
 412         netdev = dev->netdev;
 413
 414         if (!netif_device_present(netdev))
 415                 return;
 416
 417         switch (urb->status) {
 418         case 0: /* success */
 419                 break;
 420
 421         case -ENOENT:
 422                 return;
 423
 424         default:
 425                 netdev_info(netdev, "Rx URB aborted (%d)\n", urb->status);
 426                 goto resubmit_urb;
 427         }
 428
 429         if (urb->actual_length > CPC_HEADER_SIZE) {
 430                 struct ems_cpc_msg *msg;
 431                 u8 *ibuf = urb->transfer_buffer;
 432                 u8 msg_count, start;
 433
 434                 msg_count = ibuf[0] & ~0x80;
 435
 436                 start = CPC_HEADER_SIZE;
 437
 438                 while (msg_count) {
 439                         msg = (struct ems_cpc_msg *)&ibuf[start];
 440
 441                         switch (msg->type) {
 442                         case CPC_MSG_TYPE_CAN_STATE:
 443                                 /* Process CAN state changes */
 444                                 ems_usb_rx_err(dev, msg);
 445                                 break;
 446
 447                         case CPC_MSG_TYPE_CAN_FRAME:
 448                         case CPC_MSG_TYPE_EXT_CAN_FRAME:
 449                         case CPC_MSG_TYPE_RTR_FRAME:
 450                         case CPC_MSG_TYPE_EXT_RTR_FRAME:
 451                                 ems_usb_rx_can_msg(dev, msg);
 452                                 break;
 453
 454                         case CPC_MSG_TYPE_CAN_FRAME_ERROR:
 455                                 /* Process errorframe */
 456                                 ems_usb_rx_err(dev, msg);
 457                                 break;
 458
 459                         case CPC_MSG_TYPE_OVERRUN:
 460                                 /* Message lost while receiving */
 461                                 ems_usb_rx_err(dev, msg);
 462                                 break;
 463                         }
 464
 465                         start += CPC_MSG_HEADER_LEN + msg->length;
 466                         msg_count--;
 467
 468                         if (start > urb->transfer_buffer_length) {
 469                                 netdev_err(netdev, "format error\n");
 470                                 break;
 471                         }
 472                 }
 473         }
 474
 475 resubmit_urb:
 476         usb_fill_bulk_urb(urb, dev->udev, usb_rcvbulkpipe(dev->udev, 2),
 477                           urb->transfer_buffer, RX_BUFFER_SIZE,
 478                           ems_usb_read_bulk_callback, dev);
 479
 480         retval = usb_submit_urb(urb, GFP_ATOMIC);
 481
 482         if (retval == -ENODEV)
 483                 netif_device_detach(netdev);
 484         else if (retval)
 485                 netdev_err(netdev,
 486                            "failed resubmitting read bulk urb: %d\n", retval);
 487 }
 488
 489 /*
 490  * callback for bulk IN urb
 491  */
 492 static void ems_usb_write_bulk_callback(struct urb *urb)
 493 {
 494         struct ems_tx_urb_context *context = urb->context;
 495         struct ems_usb *dev;
 496         struct net_device *netdev;
 497
 498         BUG_ON(!context);
 499
 500         dev = context->dev;
 501         netdev = dev->netdev;
 502
 503         /* free up our allocated buffer */
 504         usb_free_coherent(urb->dev, urb->transfer_buffer_length,
 505                           urb->transfer_buffer, urb->transfer_dma);
 506
 507         atomic_dec(&dev->active_tx_urbs);
 508
 509         if (!netif_device_present(netdev))
 510                 return;
 511
 512         if (urb->status)
 513                 netdev_info(netdev, "Tx URB aborted (%d)\n", urb->status);
 514
 515         netif_trans_update(netdev);
 516
 517         /* transmission complete interrupt */
 518         netdev->stats.tx_packets++;
 519         netdev->stats.tx_bytes += can_get_echo_skb(netdev, context->echo_index,
 520                                                    NULL);
 521
 522         /* Release context */
 523         context->echo_index = MAX_TX_URBS;
 524
 525 }
 526
 527 /*
 528  * Send the given CPC command synchronously
 529  */
 530 static int ems_usb_command_msg(struct ems_usb *dev, struct ems_cpc_msg *msg)
 531 {
 532         int actual_length;
 533
 534         /* Copy payload */
 535         memcpy(&dev->tx_msg_buffer[CPC_HEADER_SIZE], msg,
 536                msg->length + CPC_MSG_HEADER_LEN);
 537
 538         /* Clear header */
 539         memset(&dev->tx_msg_buffer[0], 0, CPC_HEADER_SIZE);
 540
 541         return usb_bulk_msg(dev->udev, usb_sndbulkpipe(dev->udev, 2),
 542                             &dev->tx_msg_buffer[0],
 543                             msg->length + CPC_MSG_HEADER_LEN + CPC_HEADER_SIZE,
 544                             &actual_length, 1000);
 545 }
 546
 547 /*
 548  * Change CAN controllers' mode register
 549  */
 550 static int ems_usb_write_mode(struct ems_usb *dev, u8 mode)
 551 {
 552         dev->active_params.msg.can_params.cc_params.sja1000.mode = mode;
 553
 554         return ems_usb_command_msg(dev, &dev->active_params);
 555 }
 556
 557 /*
 558  * Send a CPC_Control command to change behaviour when interface receives a CAN
 559  * message, bus error or CAN state changed notifications.
 560  */
 561 static int ems_usb_control_cmd(struct ems_usb *dev, u8 val)
 562 {
 563         struct ems_cpc_msg cmd;
 564
 565         cmd.type = CPC_CMD_TYPE_CONTROL;
 566         cmd.length = CPC_MSG_HEADER_LEN + 1;
 567
 568         cmd.msgid = 0;
 569
 570         cmd.msg.generic[0] = val;
 571
 572         return ems_usb_command_msg(dev, &cmd);
 573 }
 574
 575 /*
 576  * Start interface
 577  */
 578 static int ems_usb_start(struct ems_usb *dev)
 579 {
 580         struct net_device *netdev = dev->netdev;
 581         int err, i;
 582
 583         dev->intr_in_buffer[0] = 0;
 584         dev->free_slots = 50; /* initial size */
 585
 586         for (i = 0; i < MAX_RX_URBS; i++) {
 587                 struct urb *urb = NULL;
 588                 u8 *buf = NULL;
 589                 dma_addr_t buf_dma;
 590
 591                 /* create a URB, and a buffer for it */
 592                 urb = usb_alloc_urb(0, GFP_KERNEL);
 593                 if (!urb) {
 594                         err = -ENOMEM;
 595                         break;
 596                 }
 597
 598                 buf = usb_alloc_coherent(dev->udev, RX_BUFFER_SIZE, GFP_KERNEL,
 599                                          &buf_dma);
 600                 if (!buf) {
 601                         netdev_err(netdev, "No memory left for USB buffer\n");
 602                         usb_free_urb(urb);
 603                         err = -ENOMEM;
 604                         break;
 605                 }
 606
 607                 urb->transfer_dma = buf_dma;
 608
 609                 usb_fill_bulk_urb(urb, dev->udev, usb_rcvbulkpipe(dev->udev, 2),
 610                                   buf, RX_BUFFER_SIZE,
 611                                   ems_usb_read_bulk_callback, dev);
 612                 urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 613                 usb_anchor_urb(urb, &dev->rx_submitted);
 614
 615                 err = usb_submit_urb(urb, GFP_KERNEL);
 616                 if (err) {
 617                         usb_unanchor_urb(urb);
 618                         usb_free_coherent(dev->udev, RX_BUFFER_SIZE, buf,
 619                                           urb->transfer_dma);
 620                         usb_free_urb(urb);
 621                         break;
 622                 }
 623
 624                 dev->rxbuf[i] = buf;
 625                 dev->rxbuf_dma[i] = buf_dma;
 626
 627                 /* Drop reference, USB core will take care of freeing it */
 628                 usb_free_urb(urb);
 629         }
 630
 631         /* Did we submit any URBs */
 632         if (i == 0) {
 633                 netdev_warn(netdev, "couldn't setup read URBs\n");
 634                 return err;
 635         }
 636
 637         /* Warn if we've couldn't transmit all the URBs */
 638         if (i < MAX_RX_URBS)
 639                 netdev_warn(netdev, "rx performance may be slow\n");
 640
 641         /* Setup and start interrupt URB */
 642         usb_fill_int_urb(dev->intr_urb, dev->udev,
 643                          usb_rcvintpipe(dev->udev, 1),
 644                          dev->intr_in_buffer,
 645                          INTR_IN_BUFFER_SIZE,
 646                          ems_usb_read_interrupt_callback, dev, 1);
 647
 648         err = usb_submit_urb(dev->intr_urb, GFP_KERNEL);
 649         if (err) {
 650                 netdev_warn(netdev, "intr URB submit failed: %d\n", err);
 651
 652                 return err;
 653         }
 654
 655         /* CPC-USB will transfer received message to host */
 656         err = ems_usb_control_cmd(dev, CONTR_CAN_MESSAGE | CONTR_CONT_ON);
 657         if (err)
 658                 goto failed;
 659
 660         /* CPC-USB will transfer CAN state changes to host */
 661         err = ems_usb_control_cmd(dev, CONTR_CAN_STATE | CONTR_CONT_ON);
 662         if (err)
 663                 goto failed;
 664
 665         /* CPC-USB will transfer bus errors to host */
 666         err = ems_usb_control_cmd(dev, CONTR_BUS_ERROR | CONTR_CONT_ON);
 667         if (err)
 668                 goto failed;
 669
 670         err = ems_usb_write_mode(dev, SJA1000_MOD_NORMAL);
 671         if (err)
 672                 goto failed;
 673
 674         dev->can.state = CAN_STATE_ERROR_ACTIVE;
 675
 676         return 0;
 677
 678 failed:
 679         netdev_warn(netdev, "couldn't submit control: %d\n", err);
 680
 681         return err;
 682 }
 683
 684 static void unlink_all_urbs(struct ems_usb *dev)
 685 {
 686         int i;
 687
 688         usb_unlink_urb(dev->intr_urb);
 689
 690         usb_kill_anchored_urbs(&dev->rx_submitted);
 691
 692         for (i = 0; i < MAX_RX_URBS; ++i)
 693                 usb_free_coherent(dev->udev, RX_BUFFER_SIZE,
 694                                   dev->rxbuf[i], dev->rxbuf_dma[i]);
 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                 goto nomem;
 756
 757         buf = usb_alloc_coherent(dev->udev, size, GFP_ATOMIC, &urb->transfer_dma);
 758         if (!buf) {
 759                 netdev_err(netdev, "No memory left for USB buffer\n");
 760                 usb_free_urb(urb);
 761                 goto nomem;
 762         }
 763
 764         msg = (struct ems_cpc_msg *)&buf[CPC_HEADER_SIZE];
 765
 766         msg->msg.can_msg.id = cpu_to_le32(cf->can_id & CAN_ERR_MASK);
 767         msg->msg.can_msg.length = cf->len;
 768
 769         if (cf->can_id & CAN_RTR_FLAG) {
 770                 msg->type = cf->can_id & CAN_EFF_FLAG ?
 771                         CPC_CMD_TYPE_EXT_RTR_FRAME : CPC_CMD_TYPE_RTR_FRAME;
 772
 773                 msg->length = CPC_CAN_MSG_MIN_SIZE;
 774         } else {
 775                 msg->type = cf->can_id & CAN_EFF_FLAG ?
 776                         CPC_CMD_TYPE_EXT_CAN_FRAME : CPC_CMD_TYPE_CAN_FRAME;
 777
 778                 for (i = 0; i < cf->len; i++)
 779                         msg->msg.can_msg.msg[i] = cf->data[i];
 780
 781                 msg->length = CPC_CAN_MSG_MIN_SIZE + cf->len;
 782         }
 783
 784         for (i = 0; i < MAX_TX_URBS; i++) {
 785                 if (dev->tx_contexts[i].echo_index == MAX_TX_URBS) {
 786                         context = &dev->tx_contexts[i];
 787                         break;
 788                 }
 789         }
 790
 791         /*
 792          * May never happen! When this happens we'd more URBs in flight as
 793          * allowed (MAX_TX_URBS).
 794          */
 795         if (!context) {
 796                 usb_free_coherent(dev->udev, size, buf, urb->transfer_dma);
 797                 usb_free_urb(urb);
 798
 799                 netdev_warn(netdev, "couldn't find free context\n");
 800
 801                 return NETDEV_TX_BUSY;
 802         }
 803
 804         context->dev = dev;
 805         context->echo_index = i;
 806
 807         usb_fill_bulk_urb(urb, dev->udev, usb_sndbulkpipe(dev->udev, 2), buf,
 808                           size, ems_usb_write_bulk_callback, context);
 809         urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 810         usb_anchor_urb(urb, &dev->tx_submitted);
 811
 812         can_put_echo_skb(skb, netdev, context->echo_index, 0);
 813
 814         atomic_inc(&dev->active_tx_urbs);
 815
 816         err = usb_submit_urb(urb, GFP_ATOMIC);
 817         if (unlikely(err)) {
 818                 can_free_echo_skb(netdev, context->echo_index, NULL);
 819
 820                 usb_unanchor_urb(urb);
 821                 usb_free_coherent(dev->udev, size, buf, urb->transfer_dma);
 822
 823                 atomic_dec(&dev->active_tx_urbs);
 824
 825                 if (err == -ENODEV) {
 826                         netif_device_detach(netdev);
 827                 } else {
 828                         netdev_warn(netdev, "failed tx_urb %d\n", err);
 829
 830                         stats->tx_dropped++;
 831                 }
 832         } else {
 833                 netif_trans_update(netdev);
 834
 835                 /* Slow down tx path */
 836                 if (atomic_read(&dev->active_tx_urbs) >= MAX_TX_URBS ||
 837                     dev->free_slots < CPC_TX_QUEUE_TRIGGER_LOW) {
 838                         netif_stop_queue(netdev);
 839                 }
 840         }
 841
 842         /*
 843          * Release our reference to this URB, the USB core will eventually free
 844          * it entirely.
 845          */
 846         usb_free_urb(urb);
 847
 848         return NETDEV_TX_OK;
 849
 850 nomem:
 851         dev_kfree_skb(skb);
 852         stats->tx_dropped++;
 853
 854         return NETDEV_TX_OK;
 855 }
 856
 857 static int ems_usb_close(struct net_device *netdev)
 858 {
 859         struct ems_usb *dev = netdev_priv(netdev);
 860
 861         /* Stop polling */
 862         unlink_all_urbs(dev);
 863
 864         netif_stop_queue(netdev);
 865
 866         /* Set CAN controller to reset mode */
 867         if (ems_usb_write_mode(dev, SJA1000_MOD_RM))
 868                 netdev_warn(netdev, "couldn't stop device");
 869
 870         close_candev(netdev);
 871
 872         return 0;
 873 }
 874
 875 static const struct net_device_ops ems_usb_netdev_ops = {
 876         .ndo_open = ems_usb_open,
 877         .ndo_stop = ems_usb_close,
 878         .ndo_start_xmit = ems_usb_start_xmit,
 879         .ndo_change_mtu = can_change_mtu,
 880 };
 881
 882 static const struct can_bittiming_const ems_usb_bittiming_const = {
 883         .name = KBUILD_MODNAME,
 884         .tseg1_min = 1,
 885         .tseg1_max = 16,
 886         .tseg2_min = 1,
 887         .tseg2_max = 8,
 888         .sjw_max = 4,
 889         .brp_min = 1,
 890         .brp_max = 64,
 891         .brp_inc = 1,
 892 };
 893
 894 static int ems_usb_set_mode(struct net_device *netdev, enum can_mode mode)
 895 {
 896         struct ems_usb *dev = netdev_priv(netdev);
 897
 898         switch (mode) {
 899         case CAN_MODE_START:
 900                 if (ems_usb_write_mode(dev, SJA1000_MOD_NORMAL))
 901                         netdev_warn(netdev, "couldn't start device");
 902
 903                 if (netif_queue_stopped(netdev))
 904                         netif_wake_queue(netdev);
 905                 break;
 906
 907         default:
 908                 return -EOPNOTSUPP;
 909         }
 910
 911         return 0;
 912 }
 913
 914 static int ems_usb_set_bittiming(struct net_device *netdev)
 915 {
 916         struct ems_usb *dev = netdev_priv(netdev);
 917         struct can_bittiming *bt = &dev->can.bittiming;
 918         u8 btr0, btr1;
 919
 920         btr0 = ((bt->brp - 1) & 0x3f) | (((bt->sjw - 1) & 0x3) << 6);
 921         btr1 = ((bt->prop_seg + bt->phase_seg1 - 1) & 0xf) |
 922                 (((bt->phase_seg2 - 1) & 0x7) << 4);
 923         if (dev->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES)
 924                 btr1 |= 0x80;
 925
 926         netdev_info(netdev, "setting BTR0=0x%02x BTR1=0x%02x\n", btr0, btr1);
 927
 928         dev->active_params.msg.can_params.cc_params.sja1000.btr0 = btr0;
 929         dev->active_params.msg.can_params.cc_params.sja1000.btr1 = btr1;
 930
 931         return ems_usb_command_msg(dev, &dev->active_params);
 932 }
 933
 934 static void init_params_sja1000(struct ems_cpc_msg *msg)
 935 {
 936         struct cpc_sja1000_params *sja1000 =
 937                 &msg->msg.can_params.cc_params.sja1000;
 938
 939         msg->type = CPC_CMD_TYPE_CAN_PARAMS;
 940         msg->length = sizeof(struct cpc_can_params);
 941         msg->msgid = 0;
 942
 943         msg->msg.can_params.cc_type = CPC_CC_TYPE_SJA1000;
 944
 945         /* Acceptance filter open */
 946         sja1000->acc_code0 = 0x00;
 947         sja1000->acc_code1 = 0x00;
 948         sja1000->acc_code2 = 0x00;
 949         sja1000->acc_code3 = 0x00;
 950
 951         /* Acceptance filter open */
 952         sja1000->acc_mask0 = 0xFF;
 953         sja1000->acc_mask1 = 0xFF;
 954         sja1000->acc_mask2 = 0xFF;
 955         sja1000->acc_mask3 = 0xFF;
 956
 957         sja1000->btr0 = 0;
 958         sja1000->btr1 = 0;
 959
 960         sja1000->outp_contr = SJA1000_DEFAULT_OUTPUT_CONTROL;
 961         sja1000->mode = SJA1000_MOD_RM;
 962 }
 963
 964 /*
 965  * probe function for new CPC-USB devices
 966  */
 967 static int ems_usb_probe(struct usb_interface *intf,
 968                          const struct usb_device_id *id)
 969 {
 970         struct net_device *netdev;
 971         struct ems_usb *dev;
 972         int i, err = -ENOMEM;
 973
 974         netdev = alloc_candev(sizeof(struct ems_usb), MAX_TX_URBS);
 975         if (!netdev) {
 976                 dev_err(&intf->dev, "ems_usb: Couldn't alloc candev\n");
 977                 return -ENOMEM;
 978         }
 979
 980         dev = netdev_priv(netdev);
 981
 982         dev->udev = interface_to_usbdev(intf);
 983         dev->netdev = netdev;
 984
 985         dev->can.state = CAN_STATE_STOPPED;
 986         dev->can.clock.freq = EMS_USB_ARM7_CLOCK;
 987         dev->can.bittiming_const = &ems_usb_bittiming_const;
 988         dev->can.do_set_bittiming = ems_usb_set_bittiming;
 989         dev->can.do_set_mode = ems_usb_set_mode;
 990         dev->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES;
 991
 992         netdev->netdev_ops = &ems_usb_netdev_ops;
 993
 994         netdev->flags |= IFF_ECHO; /* we support local echo */
 995
 996         init_usb_anchor(&dev->rx_submitted);
 997
 998         init_usb_anchor(&dev->tx_submitted);
 999         atomic_set(&dev->active_tx_urbs, 0);
1000
1001         for (i = 0; i < MAX_TX_URBS; i++)
1002                 dev->tx_contexts[i].echo_index = MAX_TX_URBS;
1003
1004         dev->intr_urb = usb_alloc_urb(0, GFP_KERNEL);
1005         if (!dev->intr_urb)
1006                 goto cleanup_candev;
1007
1008         dev->intr_in_buffer = kzalloc(INTR_IN_BUFFER_SIZE, GFP_KERNEL);
1009         if (!dev->intr_in_buffer)
1010                 goto cleanup_intr_urb;
1011
1012         dev->tx_msg_buffer = kzalloc(CPC_HEADER_SIZE +
1013                                      sizeof(struct ems_cpc_msg), GFP_KERNEL);
1014         if (!dev->tx_msg_buffer)
1015                 goto cleanup_intr_in_buffer;
1016
1017         usb_set_intfdata(intf, dev);
1018
1019         SET_NETDEV_DEV(netdev, &intf->dev);
1020
1021         init_params_sja1000(&dev->active_params);
1022
1023         err = ems_usb_command_msg(dev, &dev->active_params);
1024         if (err) {
1025                 netdev_err(netdev, "couldn't initialize controller: %d\n", err);
1026                 goto cleanup_tx_msg_buffer;
1027         }
1028
1029         err = register_candev(netdev);
1030         if (err) {
1031                 netdev_err(netdev, "couldn't register CAN device: %d\n", err);
1032                 goto cleanup_tx_msg_buffer;
1033         }
1034
1035         return 0;
1036
1037 cleanup_tx_msg_buffer:
1038         kfree(dev->tx_msg_buffer);
1039
1040 cleanup_intr_in_buffer:
1041         kfree(dev->intr_in_buffer);
1042
1043 cleanup_intr_urb:
1044         usb_free_urb(dev->intr_urb);
1045
1046 cleanup_candev:
1047         free_candev(netdev);
1048
1049         return err;
1050 }
1051
1052 /*
1053  * called by the usb core when the device is removed from the system
1054  */
1055 static void ems_usb_disconnect(struct usb_interface *intf)
1056 {
1057         struct ems_usb *dev = usb_get_intfdata(intf);
1058
1059         usb_set_intfdata(intf, NULL);
1060
1061         if (dev) {
1062                 unregister_netdev(dev->netdev);
1063
1064                 unlink_all_urbs(dev);
1065
1066                 usb_free_urb(dev->intr_urb);
1067
1068                 kfree(dev->intr_in_buffer);
1069                 kfree(dev->tx_msg_buffer);
1070
1071                 free_candev(dev->netdev);
1072         }
1073 }
1074
1075 /* usb specific object needed to register this driver with the usb subsystem */
1076 static struct usb_driver ems_usb_driver = {
1077         .name = KBUILD_MODNAME,
1078         .probe = ems_usb_probe,
1079         .disconnect = ems_usb_disconnect,
1080         .id_table = ems_usb_table,
1081 };
1082
1083 module_usb_driver(ems_usb_driver);