linux/drivers/net/can/usb/ems_usb.c
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   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
  17MODULE_AUTHOR("Sebastian Haas <haas@ems-wuensche.com>");
  18MODULE_DESCRIPTION("CAN driver for EMS Dr. Thomas Wuensche CAN/USB interfaces");
  19MODULE_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 */
 116struct 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 */
 123struct 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 */
 139struct 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 */
 149struct cpc_confirm {
 150        u8 error; /* error code */
 151};
 152
 153/* Structure for overrun conditions */
 154struct cpc_overrun {
 155        u8 event;
 156        u8 count;
 157};
 158
 159/* SJA1000 CAN errors (compatible to NXP LPC2119) */
 160struct cpc_sja1000_can_error {
 161        u8 ecc;
 162        u8 rxerr;
 163        u8 txerr;
 164};
 165
 166/* structure for CAN error conditions */
 167struct 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 */
 184struct cpc_can_err_counter {
 185        u8 rx;
 186        u8 tx;
 187};
 188
 189/* Main message type used between library and application */
 190struct __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 */
 213static struct usb_device_id ems_usb_table[] = {
 214        {USB_DEVICE(USB_CPCUSB_VENDOR_ID, USB_CPCUSB_ARM7_PRODUCT_ID)},
 215        {} /* Terminating entry */
 216};
 217
 218MODULE_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
 227struct ems_usb;
 228
 229struct ems_tx_urb_context {
 230        struct ems_usb *dev;
 231
 232        u32 echo_index;
 233        u8 dlc;
 234};
 235
 236struct ems_usb {
 237        struct can_priv can; /* must be the first member */
 238
 239        struct sk_buff *echo_skb[MAX_TX_URBS];
 240
 241        struct usb_device *udev;
 242        struct net_device *netdev;
 243
 244        atomic_t active_tx_urbs;
 245        struct usb_anchor tx_submitted;
 246        struct ems_tx_urb_context tx_contexts[MAX_TX_URBS];
 247
 248        struct usb_anchor rx_submitted;
 249
 250        struct urb *intr_urb;
 251
 252        u8 *tx_msg_buffer;
 253
 254        u8 *intr_in_buffer;
 255        unsigned int free_slots; /* remember number of available slots */
 256
 257        struct ems_cpc_msg active_params; /* active controller parameters */
 258};
 259
 260static void ems_usb_read_interrupt_callback(struct urb *urb)
 261{
 262        struct ems_usb *dev = urb->context;
 263        struct net_device *netdev = dev->netdev;
 264        int err;
 265
 266        if (!netif_device_present(netdev))
 267                return;
 268
 269        switch (urb->status) {
 270        case 0:
 271                dev->free_slots = dev->intr_in_buffer[1];
 272                if (dev->free_slots > CPC_TX_QUEUE_TRIGGER_HIGH &&
 273                    netif_queue_stopped(netdev))
 274                        netif_wake_queue(netdev);
 275                break;
 276
 277        case -ECONNRESET: /* unlink */
 278        case -ENOENT:
 279        case -EPIPE:
 280        case -EPROTO:
 281        case -ESHUTDOWN:
 282                return;
 283
 284        default:
 285                netdev_info(netdev, "Rx interrupt aborted %d\n", urb->status);
 286                break;
 287        }
 288
 289        err = usb_submit_urb(urb, GFP_ATOMIC);
 290
 291        if (err == -ENODEV)
 292                netif_device_detach(netdev);
 293        else if (err)
 294                netdev_err(netdev, "failed resubmitting intr urb: %d\n", err);
 295}
 296
 297static void ems_usb_rx_can_msg(struct ems_usb *dev, struct ems_cpc_msg *msg)
 298{
 299        struct can_frame *cf;
 300        struct sk_buff *skb;
 301        int i;
 302        struct net_device_stats *stats = &dev->netdev->stats;
 303
 304        skb = alloc_can_skb(dev->netdev, &cf);
 305        if (skb == NULL)
 306                return;
 307
 308        cf->can_id = le32_to_cpu(msg->msg.can_msg.id);
 309        cf->len = can_cc_dlc2len(msg->msg.can_msg.length & 0xF);
 310
 311        if (msg->type == CPC_MSG_TYPE_EXT_CAN_FRAME ||
 312            msg->type == CPC_MSG_TYPE_EXT_RTR_FRAME)
 313                cf->can_id |= CAN_EFF_FLAG;
 314
 315        if (msg->type == CPC_MSG_TYPE_RTR_FRAME ||
 316            msg->type == CPC_MSG_TYPE_EXT_RTR_FRAME) {
 317                cf->can_id |= CAN_RTR_FLAG;
 318        } else {
 319                for (i = 0; i < cf->len; i++)
 320                        cf->data[i] = msg->msg.can_msg.msg[i];
 321        }
 322
 323        stats->rx_packets++;
 324        stats->rx_bytes += cf->len;
 325        netif_rx(skb);
 326}
 327
 328static void ems_usb_rx_err(struct ems_usb *dev, struct ems_cpc_msg *msg)
 329{
 330        struct can_frame *cf;
 331        struct sk_buff *skb;
 332        struct net_device_stats *stats = &dev->netdev->stats;
 333
 334        skb = alloc_can_err_skb(dev->netdev, &cf);
 335        if (skb == NULL)
 336                return;
 337
 338        if (msg->type == CPC_MSG_TYPE_CAN_STATE) {
 339                u8 state = msg->msg.can_state;
 340
 341                if (state & SJA1000_SR_BS) {
 342                        dev->can.state = CAN_STATE_BUS_OFF;
 343                        cf->can_id |= CAN_ERR_BUSOFF;
 344
 345                        dev->can.can_stats.bus_off++;
 346                        can_bus_off(dev->netdev);
 347                } else if (state & SJA1000_SR_ES) {
 348                        dev->can.state = CAN_STATE_ERROR_WARNING;
 349                        dev->can.can_stats.error_warning++;
 350                } else {
 351                        dev->can.state = CAN_STATE_ERROR_ACTIVE;
 352                        dev->can.can_stats.error_passive++;
 353                }
 354        } else if (msg->type == CPC_MSG_TYPE_CAN_FRAME_ERROR) {
 355                u8 ecc = msg->msg.error.cc.regs.sja1000.ecc;
 356                u8 txerr = msg->msg.error.cc.regs.sja1000.txerr;
 357                u8 rxerr = msg->msg.error.cc.regs.sja1000.rxerr;
 358
 359                /* bus error interrupt */
 360                dev->can.can_stats.bus_error++;
 361                stats->rx_errors++;
 362
 363                cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
 364
 365                switch (ecc & SJA1000_ECC_MASK) {
 366                case SJA1000_ECC_BIT:
 367                        cf->data[2] |= CAN_ERR_PROT_BIT;
 368                        break;
 369                case SJA1000_ECC_FORM:
 370                        cf->data[2] |= CAN_ERR_PROT_FORM;
 371                        break;
 372                case SJA1000_ECC_STUFF:
 373                        cf->data[2] |= CAN_ERR_PROT_STUFF;
 374                        break;
 375                default:
 376                        cf->data[3] = ecc & SJA1000_ECC_SEG;
 377                        break;
 378                }
 379
 380                /* Error occurred during transmission? */
 381                if ((ecc & SJA1000_ECC_DIR) == 0)
 382                        cf->data[2] |= CAN_ERR_PROT_TX;
 383
 384                if (dev->can.state == CAN_STATE_ERROR_WARNING ||
 385                    dev->can.state == CAN_STATE_ERROR_PASSIVE) {
 386                        cf->can_id |= CAN_ERR_CRTL;
 387                        cf->data[1] = (txerr > rxerr) ?
 388                            CAN_ERR_CRTL_TX_PASSIVE : CAN_ERR_CRTL_RX_PASSIVE;
 389                }
 390        } else if (msg->type == CPC_MSG_TYPE_OVERRUN) {
 391                cf->can_id |= CAN_ERR_CRTL;
 392                cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
 393
 394                stats->rx_over_errors++;
 395                stats->rx_errors++;
 396        }
 397
 398        stats->rx_packets++;
 399        stats->rx_bytes += cf->len;
 400        netif_rx(skb);
 401}
 402
 403/*
 404 * callback for bulk IN urb
 405 */
 406static 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
 475resubmit_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 */
 492static 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 += context->dlc;
 520
 521        can_get_echo_skb(netdev, context->echo_index, NULL);
 522
 523        /* Release context */
 524        context->echo_index = MAX_TX_URBS;
 525
 526}
 527
 528/*
 529 * Send the given CPC command synchronously
 530 */
 531static int ems_usb_command_msg(struct ems_usb *dev, struct ems_cpc_msg *msg)
 532{
 533        int actual_length;
 534
 535        /* Copy payload */
 536        memcpy(&dev->tx_msg_buffer[CPC_HEADER_SIZE], msg,
 537               msg->length + CPC_MSG_HEADER_LEN);
 538
 539        /* Clear header */
 540        memset(&dev->tx_msg_buffer[0], 0, CPC_HEADER_SIZE);
 541
 542        return usb_bulk_msg(dev->udev, usb_sndbulkpipe(dev->udev, 2),
 543                            &dev->tx_msg_buffer[0],
 544                            msg->length + CPC_MSG_HEADER_LEN + CPC_HEADER_SIZE,
 545                            &actual_length, 1000);
 546}
 547
 548/*
 549 * Change CAN controllers' mode register
 550 */
 551static int ems_usb_write_mode(struct ems_usb *dev, u8 mode)
 552{
 553        dev->active_params.msg.can_params.cc_params.sja1000.mode = mode;
 554
 555        return ems_usb_command_msg(dev, &dev->active_params);
 556}
 557
 558/*
 559 * Send a CPC_Control command to change behaviour when interface receives a CAN
 560 * message, bus error or CAN state changed notifications.
 561 */
 562static int ems_usb_control_cmd(struct ems_usb *dev, u8 val)
 563{
 564        struct ems_cpc_msg cmd;
 565
 566        cmd.type = CPC_CMD_TYPE_CONTROL;
 567        cmd.length = CPC_MSG_HEADER_LEN + 1;
 568
 569        cmd.msgid = 0;
 570
 571        cmd.msg.generic[0] = val;
 572
 573        return ems_usb_command_msg(dev, &cmd);
 574}
 575
 576/*
 577 * Start interface
 578 */
 579static int ems_usb_start(struct ems_usb *dev)
 580{
 581        struct net_device *netdev = dev->netdev;
 582        int err, i;
 583
 584        dev->intr_in_buffer[0] = 0;
 585        dev->free_slots = 50; /* initial size */
 586
 587        for (i = 0; i < MAX_RX_URBS; i++) {
 588                struct urb *urb = NULL;
 589                u8 *buf = NULL;
 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                                         &urb->transfer_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                usb_fill_bulk_urb(urb, dev->udev, usb_rcvbulkpipe(dev->udev, 2),
 608                                  buf, RX_BUFFER_SIZE,
 609                                  ems_usb_read_bulk_callback, dev);
 610                urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 611                usb_anchor_urb(urb, &dev->rx_submitted);
 612
 613                err = usb_submit_urb(urb, GFP_KERNEL);
 614                if (err) {
 615                        usb_unanchor_urb(urb);
 616                        usb_free_coherent(dev->udev, RX_BUFFER_SIZE, buf,
 617                                          urb->transfer_dma);
 618                        usb_free_urb(urb);
 619                        break;
 620                }
 621
 622                /* Drop reference, USB core will take care of freeing it */
 623                usb_free_urb(urb);
 624        }
 625
 626        /* Did we submit any URBs */
 627        if (i == 0) {
 628                netdev_warn(netdev, "couldn't setup read URBs\n");
 629                return err;
 630        }
 631
 632        /* Warn if we've couldn't transmit all the URBs */
 633        if (i < MAX_RX_URBS)
 634                netdev_warn(netdev, "rx performance may be slow\n");
 635
 636        /* Setup and start interrupt URB */
 637        usb_fill_int_urb(dev->intr_urb, dev->udev,
 638                         usb_rcvintpipe(dev->udev, 1),
 639                         dev->intr_in_buffer,
 640                         INTR_IN_BUFFER_SIZE,
 641                         ems_usb_read_interrupt_callback, dev, 1);
 642
 643        err = usb_submit_urb(dev->intr_urb, GFP_KERNEL);
 644        if (err) {
 645                netdev_warn(netdev, "intr URB submit failed: %d\n", err);
 646
 647                return err;
 648        }
 649
 650        /* CPC-USB will transfer received message to host */
 651        err = ems_usb_control_cmd(dev, CONTR_CAN_MESSAGE | CONTR_CONT_ON);
 652        if (err)
 653                goto failed;
 654
 655        /* CPC-USB will transfer CAN state changes to host */
 656        err = ems_usb_control_cmd(dev, CONTR_CAN_STATE | CONTR_CONT_ON);
 657        if (err)
 658                goto failed;
 659
 660        /* CPC-USB will transfer bus errors to host */
 661        err = ems_usb_control_cmd(dev, CONTR_BUS_ERROR | CONTR_CONT_ON);
 662        if (err)
 663                goto failed;
 664
 665        err = ems_usb_write_mode(dev, SJA1000_MOD_NORMAL);
 666        if (err)
 667                goto failed;
 668
 669        dev->can.state = CAN_STATE_ERROR_ACTIVE;
 670
 671        return 0;
 672
 673failed:
 674        netdev_warn(netdev, "couldn't submit control: %d\n", err);
 675
 676        return err;
 677}
 678
 679static void unlink_all_urbs(struct ems_usb *dev)
 680{
 681        int i;
 682
 683        usb_unlink_urb(dev->intr_urb);
 684
 685        usb_kill_anchored_urbs(&dev->rx_submitted);
 686
 687        usb_kill_anchored_urbs(&dev->tx_submitted);
 688        atomic_set(&dev->active_tx_urbs, 0);
 689
 690        for (i = 0; i < MAX_TX_URBS; i++)
 691                dev->tx_contexts[i].echo_index = MAX_TX_URBS;
 692}
 693
 694static int ems_usb_open(struct net_device *netdev)
 695{
 696        struct ems_usb *dev = netdev_priv(netdev);
 697        int err;
 698
 699        err = ems_usb_write_mode(dev, SJA1000_MOD_RM);
 700        if (err)
 701                return err;
 702
 703        /* common open */
 704        err = open_candev(netdev);
 705        if (err)
 706                return err;
 707
 708        /* finally start device */
 709        err = ems_usb_start(dev);
 710        if (err) {
 711                if (err == -ENODEV)
 712                        netif_device_detach(dev->netdev);
 713
 714                netdev_warn(netdev, "couldn't start device: %d\n", err);
 715
 716                close_candev(netdev);
 717
 718                return err;
 719        }
 720
 721
 722        netif_start_queue(netdev);
 723
 724        return 0;
 725}
 726
 727static netdev_tx_t ems_usb_start_xmit(struct sk_buff *skb, struct net_device *netdev)
 728{
 729        struct ems_usb *dev = netdev_priv(netdev);
 730        struct ems_tx_urb_context *context = NULL;
 731        struct net_device_stats *stats = &netdev->stats;
 732        struct can_frame *cf = (struct can_frame *)skb->data;
 733        struct ems_cpc_msg *msg;
 734        struct urb *urb;
 735        u8 *buf;
 736        int i, err;
 737        size_t size = CPC_HEADER_SIZE + CPC_MSG_HEADER_LEN
 738                        + sizeof(struct cpc_can_msg);
 739
 740        if (can_dropped_invalid_skb(netdev, skb))
 741                return NETDEV_TX_OK;
 742
 743        /* create a URB, and a buffer for it, and copy the data to the URB */
 744        urb = usb_alloc_urb(0, GFP_ATOMIC);
 745        if (!urb)
 746                goto nomem;
 747
 748        buf = usb_alloc_coherent(dev->udev, size, GFP_ATOMIC, &urb->transfer_dma);
 749        if (!buf) {
 750                netdev_err(netdev, "No memory left for USB buffer\n");
 751                usb_free_urb(urb);
 752                goto nomem;
 753        }
 754
 755        msg = (struct ems_cpc_msg *)&buf[CPC_HEADER_SIZE];
 756
 757        msg->msg.can_msg.id = cpu_to_le32(cf->can_id & CAN_ERR_MASK);
 758        msg->msg.can_msg.length = cf->len;
 759
 760        if (cf->can_id & CAN_RTR_FLAG) {
 761                msg->type = cf->can_id & CAN_EFF_FLAG ?
 762                        CPC_CMD_TYPE_EXT_RTR_FRAME : CPC_CMD_TYPE_RTR_FRAME;
 763
 764                msg->length = CPC_CAN_MSG_MIN_SIZE;
 765        } else {
 766                msg->type = cf->can_id & CAN_EFF_FLAG ?
 767                        CPC_CMD_TYPE_EXT_CAN_FRAME : CPC_CMD_TYPE_CAN_FRAME;
 768
 769                for (i = 0; i < cf->len; i++)
 770                        msg->msg.can_msg.msg[i] = cf->data[i];
 771
 772                msg->length = CPC_CAN_MSG_MIN_SIZE + cf->len;
 773        }
 774
 775        for (i = 0; i < MAX_TX_URBS; i++) {
 776                if (dev->tx_contexts[i].echo_index == MAX_TX_URBS) {
 777                        context = &dev->tx_contexts[i];
 778                        break;
 779                }
 780        }
 781
 782        /*
 783         * May never happen! When this happens we'd more URBs in flight as
 784         * allowed (MAX_TX_URBS).
 785         */
 786        if (!context) {
 787                usb_free_coherent(dev->udev, size, buf, urb->transfer_dma);
 788                usb_free_urb(urb);
 789
 790                netdev_warn(netdev, "couldn't find free context\n");
 791
 792                return NETDEV_TX_BUSY;
 793        }
 794
 795        context->dev = dev;
 796        context->echo_index = i;
 797        context->dlc = cf->len;
 798
 799        usb_fill_bulk_urb(urb, dev->udev, usb_sndbulkpipe(dev->udev, 2), buf,
 800                          size, ems_usb_write_bulk_callback, context);
 801        urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 802        usb_anchor_urb(urb, &dev->tx_submitted);
 803
 804        can_put_echo_skb(skb, netdev, context->echo_index, 0);
 805
 806        atomic_inc(&dev->active_tx_urbs);
 807
 808        err = usb_submit_urb(urb, GFP_ATOMIC);
 809        if (unlikely(err)) {
 810                can_free_echo_skb(netdev, context->echo_index, NULL);
 811
 812                usb_unanchor_urb(urb);
 813                usb_free_coherent(dev->udev, size, buf, urb->transfer_dma);
 814                dev_kfree_skb(skb);
 815
 816                atomic_dec(&dev->active_tx_urbs);
 817
 818                if (err == -ENODEV) {
 819                        netif_device_detach(netdev);
 820                } else {
 821                        netdev_warn(netdev, "failed tx_urb %d\n", err);
 822
 823                        stats->tx_dropped++;
 824                }
 825        } else {
 826                netif_trans_update(netdev);
 827
 828                /* Slow down tx path */
 829                if (atomic_read(&dev->active_tx_urbs) >= MAX_TX_URBS ||
 830                    dev->free_slots < CPC_TX_QUEUE_TRIGGER_LOW) {
 831                        netif_stop_queue(netdev);
 832                }
 833        }
 834
 835        /*
 836         * Release our reference to this URB, the USB core will eventually free
 837         * it entirely.
 838         */
 839        usb_free_urb(urb);
 840
 841        return NETDEV_TX_OK;
 842
 843nomem:
 844        dev_kfree_skb(skb);
 845        stats->tx_dropped++;
 846
 847        return NETDEV_TX_OK;
 848}
 849
 850static int ems_usb_close(struct net_device *netdev)
 851{
 852        struct ems_usb *dev = netdev_priv(netdev);
 853
 854        /* Stop polling */
 855        unlink_all_urbs(dev);
 856
 857        netif_stop_queue(netdev);
 858
 859        /* Set CAN controller to reset mode */
 860        if (ems_usb_write_mode(dev, SJA1000_MOD_RM))
 861                netdev_warn(netdev, "couldn't stop device");
 862
 863        close_candev(netdev);
 864
 865        return 0;
 866}
 867
 868static const struct net_device_ops ems_usb_netdev_ops = {
 869        .ndo_open = ems_usb_open,
 870        .ndo_stop = ems_usb_close,
 871        .ndo_start_xmit = ems_usb_start_xmit,
 872        .ndo_change_mtu = can_change_mtu,
 873};
 874
 875static const struct can_bittiming_const ems_usb_bittiming_const = {
 876        .name = "ems_usb",
 877        .tseg1_min = 1,
 878        .tseg1_max = 16,
 879        .tseg2_min = 1,
 880        .tseg2_max = 8,
 881        .sjw_max = 4,
 882        .brp_min = 1,
 883        .brp_max = 64,
 884        .brp_inc = 1,
 885};
 886
 887static int ems_usb_set_mode(struct net_device *netdev, enum can_mode mode)
 888{
 889        struct ems_usb *dev = netdev_priv(netdev);
 890
 891        switch (mode) {
 892        case CAN_MODE_START:
 893                if (ems_usb_write_mode(dev, SJA1000_MOD_NORMAL))
 894                        netdev_warn(netdev, "couldn't start device");
 895
 896                if (netif_queue_stopped(netdev))
 897                        netif_wake_queue(netdev);
 898                break;
 899
 900        default:
 901                return -EOPNOTSUPP;
 902        }
 903
 904        return 0;
 905}
 906
 907static int ems_usb_set_bittiming(struct net_device *netdev)
 908{
 909        struct ems_usb *dev = netdev_priv(netdev);
 910        struct can_bittiming *bt = &dev->can.bittiming;
 911        u8 btr0, btr1;
 912
 913        btr0 = ((bt->brp - 1) & 0x3f) | (((bt->sjw - 1) & 0x3) << 6);
 914        btr1 = ((bt->prop_seg + bt->phase_seg1 - 1) & 0xf) |
 915                (((bt->phase_seg2 - 1) & 0x7) << 4);
 916        if (dev->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES)
 917                btr1 |= 0x80;
 918
 919        netdev_info(netdev, "setting BTR0=0x%02x BTR1=0x%02x\n", btr0, btr1);
 920
 921        dev->active_params.msg.can_params.cc_params.sja1000.btr0 = btr0;
 922        dev->active_params.msg.can_params.cc_params.sja1000.btr1 = btr1;
 923
 924        return ems_usb_command_msg(dev, &dev->active_params);
 925}
 926
 927static void init_params_sja1000(struct ems_cpc_msg *msg)
 928{
 929        struct cpc_sja1000_params *sja1000 =
 930                &msg->msg.can_params.cc_params.sja1000;
 931
 932        msg->type = CPC_CMD_TYPE_CAN_PARAMS;
 933        msg->length = sizeof(struct cpc_can_params);
 934        msg->msgid = 0;
 935
 936        msg->msg.can_params.cc_type = CPC_CC_TYPE_SJA1000;
 937
 938        /* Acceptance filter open */
 939        sja1000->acc_code0 = 0x00;
 940        sja1000->acc_code1 = 0x00;
 941        sja1000->acc_code2 = 0x00;
 942        sja1000->acc_code3 = 0x00;
 943
 944        /* Acceptance filter open */
 945        sja1000->acc_mask0 = 0xFF;
 946        sja1000->acc_mask1 = 0xFF;
 947        sja1000->acc_mask2 = 0xFF;
 948        sja1000->acc_mask3 = 0xFF;
 949
 950        sja1000->btr0 = 0;
 951        sja1000->btr1 = 0;
 952
 953        sja1000->outp_contr = SJA1000_DEFAULT_OUTPUT_CONTROL;
 954        sja1000->mode = SJA1000_MOD_RM;
 955}
 956
 957/*
 958 * probe function for new CPC-USB devices
 959 */
 960static int ems_usb_probe(struct usb_interface *intf,
 961                         const struct usb_device_id *id)
 962{
 963        struct net_device *netdev;
 964        struct ems_usb *dev;
 965        int i, err = -ENOMEM;
 966
 967        netdev = alloc_candev(sizeof(struct ems_usb), MAX_TX_URBS);
 968        if (!netdev) {
 969                dev_err(&intf->dev, "ems_usb: Couldn't alloc candev\n");
 970                return -ENOMEM;
 971        }
 972
 973        dev = netdev_priv(netdev);
 974
 975        dev->udev = interface_to_usbdev(intf);
 976        dev->netdev = netdev;
 977
 978        dev->can.state = CAN_STATE_STOPPED;
 979        dev->can.clock.freq = EMS_USB_ARM7_CLOCK;
 980        dev->can.bittiming_const = &ems_usb_bittiming_const;
 981        dev->can.do_set_bittiming = ems_usb_set_bittiming;
 982        dev->can.do_set_mode = ems_usb_set_mode;
 983        dev->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES;
 984
 985        netdev->netdev_ops = &ems_usb_netdev_ops;
 986
 987        netdev->flags |= IFF_ECHO; /* we support local echo */
 988
 989        init_usb_anchor(&dev->rx_submitted);
 990
 991        init_usb_anchor(&dev->tx_submitted);
 992        atomic_set(&dev->active_tx_urbs, 0);
 993
 994        for (i = 0; i < MAX_TX_URBS; i++)
 995                dev->tx_contexts[i].echo_index = MAX_TX_URBS;
 996
 997        dev->intr_urb = usb_alloc_urb(0, GFP_KERNEL);
 998        if (!dev->intr_urb)
 999                goto cleanup_candev;
1000
1001        dev->intr_in_buffer = kzalloc(INTR_IN_BUFFER_SIZE, GFP_KERNEL);
1002        if (!dev->intr_in_buffer)
1003                goto cleanup_intr_urb;
1004
1005        dev->tx_msg_buffer = kzalloc(CPC_HEADER_SIZE +
1006                                     sizeof(struct ems_cpc_msg), GFP_KERNEL);
1007        if (!dev->tx_msg_buffer)
1008                goto cleanup_intr_in_buffer;
1009
1010        usb_set_intfdata(intf, dev);
1011
1012        SET_NETDEV_DEV(netdev, &intf->dev);
1013
1014        init_params_sja1000(&dev->active_params);
1015
1016        err = ems_usb_command_msg(dev, &dev->active_params);
1017        if (err) {
1018                netdev_err(netdev, "couldn't initialize controller: %d\n", err);
1019                goto cleanup_tx_msg_buffer;
1020        }
1021
1022        err = register_candev(netdev);
1023        if (err) {
1024                netdev_err(netdev, "couldn't register CAN device: %d\n", err);
1025                goto cleanup_tx_msg_buffer;
1026        }
1027
1028        return 0;
1029
1030cleanup_tx_msg_buffer:
1031        kfree(dev->tx_msg_buffer);
1032
1033cleanup_intr_in_buffer:
1034        kfree(dev->intr_in_buffer);
1035
1036cleanup_intr_urb:
1037        usb_free_urb(dev->intr_urb);
1038
1039cleanup_candev:
1040        free_candev(netdev);
1041
1042        return err;
1043}
1044
1045/*
1046 * called by the usb core when the device is removed from the system
1047 */
1048static void ems_usb_disconnect(struct usb_interface *intf)
1049{
1050        struct ems_usb *dev = usb_get_intfdata(intf);
1051
1052        usb_set_intfdata(intf, NULL);
1053
1054        if (dev) {
1055                unregister_netdev(dev->netdev);
1056                free_candev(dev->netdev);
1057
1058                unlink_all_urbs(dev);
1059
1060                usb_free_urb(dev->intr_urb);
1061
1062                kfree(dev->intr_in_buffer);
1063                kfree(dev->tx_msg_buffer);
1064        }
1065}
1066
1067/* usb specific object needed to register this driver with the usb subsystem */
1068static struct usb_driver ems_usb_driver = {
1069        .name = "ems_usb",
1070        .probe = ems_usb_probe,
1071        .disconnect = ems_usb_disconnect,
1072        .id_table = ems_usb_table,
1073};
1074
1075module_usb_driver(ems_usb_driver);
1076