drivers/net/can/usb/gs_usb.c

   1 /* CAN driver for Geschwister Schneider USB/CAN devices.
   2  *
   3  * Copyright (C) 2013 Geschwister Schneider Technologie-,
   4  * Entwicklungs- und Vertriebs UG (Haftungsbeschränkt).
   5  *
   6  * Many thanks to all socketcan devs!
   7  *
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms of the GNU General Public License as published
  10  * by the Free Software Foundation; version 2 of the License.
  11  *
  12  * This program is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  15  * General Public License for more details.
  16  */
  17
  18 #include <linux/init.h>
  19 #include <linux/signal.h>
  20 #include <linux/module.h>
  21 #include <linux/netdevice.h>
  22 #include <linux/usb.h>
  23
  24 #include <linux/can.h>
  25 #include <linux/can/dev.h>
  26 #include <linux/can/error.h>
  27
  28 /* Device specific constants */
  29 #define USB_GSUSB_1_VENDOR_ID      0x1d50
  30 #define USB_GSUSB_1_PRODUCT_ID     0x606f
  31
  32 #define GSUSB_ENDPOINT_IN          1
  33 #define GSUSB_ENDPOINT_OUT         2
  34
  35 /* Device specific constants */
  36 enum gs_usb_breq {
  37         GS_USB_BREQ_HOST_FORMAT = 0,
  38         GS_USB_BREQ_BITTIMING,
  39         GS_USB_BREQ_MODE,
  40         GS_USB_BREQ_BERR,
  41         GS_USB_BREQ_BT_CONST,
  42         GS_USB_BREQ_DEVICE_CONFIG
  43 };
  44
  45 enum gs_can_mode {
  46         /* reset a channel. turns it off */
  47         GS_CAN_MODE_RESET = 0,
  48         /* starts a channel */
  49         GS_CAN_MODE_START
  50 };
  51
  52 enum gs_can_state {
  53         GS_CAN_STATE_ERROR_ACTIVE = 0,
  54         GS_CAN_STATE_ERROR_WARNING,
  55         GS_CAN_STATE_ERROR_PASSIVE,
  56         GS_CAN_STATE_BUS_OFF,
  57         GS_CAN_STATE_STOPPED,
  58         GS_CAN_STATE_SLEEPING
  59 };
  60
  61 /* data types passed between host and device */
  62 struct gs_host_config {
  63         u32 byte_order;
  64 } __packed;
  65 /* All data exchanged between host and device is exchanged in host byte order,
  66  * thanks to the struct gs_host_config byte_order member, which is sent first
  67  * to indicate the desired byte order.
  68  */
  69
  70 struct gs_device_config {
  71         u8 reserved1;
  72         u8 reserved2;
  73         u8 reserved3;
  74         u8 icount;
  75         u32 sw_version;
  76         u32 hw_version;
  77 } __packed;
  78
  79 #define GS_CAN_MODE_NORMAL               0
  80 #define GS_CAN_MODE_LISTEN_ONLY          (1<<0)
  81 #define GS_CAN_MODE_LOOP_BACK            (1<<1)
  82 #define GS_CAN_MODE_TRIPLE_SAMPLE        (1<<2)
  83 #define GS_CAN_MODE_ONE_SHOT             (1<<3)
  84
  85 struct gs_device_mode {
  86         u32 mode;
  87         u32 flags;
  88 } __packed;
  89
  90 struct gs_device_state {
  91         u32 state;
  92         u32 rxerr;
  93         u32 txerr;
  94 } __packed;
  95
  96 struct gs_device_bittiming {
  97         u32 prop_seg;
  98         u32 phase_seg1;
  99         u32 phase_seg2;
 100         u32 sjw;
 101         u32 brp;
 102 } __packed;
 103
 104 #define GS_CAN_FEATURE_LISTEN_ONLY      (1<<0)
 105 #define GS_CAN_FEATURE_LOOP_BACK        (1<<1)
 106 #define GS_CAN_FEATURE_TRIPLE_SAMPLE    (1<<2)
 107 #define GS_CAN_FEATURE_ONE_SHOT         (1<<3)
 108
 109 struct gs_device_bt_const {
 110         u32 feature;
 111         u32 fclk_can;
 112         u32 tseg1_min;
 113         u32 tseg1_max;
 114         u32 tseg2_min;
 115         u32 tseg2_max;
 116         u32 sjw_max;
 117         u32 brp_min;
 118         u32 brp_max;
 119         u32 brp_inc;
 120 } __packed;
 121
 122 #define GS_CAN_FLAG_OVERFLOW 1
 123
 124 struct gs_host_frame {
 125         u32 echo_id;
 126         u32 can_id;
 127
 128         u8 can_dlc;
 129         u8 channel;
 130         u8 flags;
 131         u8 reserved;
 132
 133         u8 data[8];
 134 } __packed;
 135 /* The GS USB devices make use of the same flags and masks as in
 136  * linux/can.h and linux/can/error.h, and no additional mapping is necessary.
 137  */
 138
 139 /* Only send a max of GS_MAX_TX_URBS frames per channel at a time. */
 140 #define GS_MAX_TX_URBS 10
 141 /* Only launch a max of GS_MAX_RX_URBS usb requests at a time. */
 142 #define GS_MAX_RX_URBS 30
 143 /* Maximum number of interfaces the driver supports per device.
 144  * Current hardware only supports 2 interfaces. The future may vary.
 145  */
 146 #define GS_MAX_INTF 2
 147
 148 struct gs_tx_context {
 149         struct gs_can *dev;
 150         unsigned int echo_id;
 151 };
 152
 153 struct gs_can {
 154         struct can_priv can; /* must be the first member */
 155
 156         struct gs_usb *parent;
 157
 158         struct net_device *netdev;
 159         struct usb_device *udev;
 160         struct usb_interface *iface;
 161
 162         struct can_bittiming_const bt_const;
 163         unsigned int channel;   /* channel number */
 164
 165         /* This lock prevents a race condition between xmit and recieve. */
 166         spinlock_t tx_ctx_lock;
 167         struct gs_tx_context tx_context[GS_MAX_TX_URBS];
 168
 169         struct usb_anchor tx_submitted;
 170         atomic_t active_tx_urbs;
 171 };
 172
 173 /* usb interface struct */
 174 struct gs_usb {
 175         struct gs_can *canch[GS_MAX_INTF];
 176         struct usb_anchor rx_submitted;
 177         atomic_t active_channels;
 178         struct usb_device *udev;
 179 };
 180
 181 /* 'allocate' a tx context.
 182  * returns a valid tx context or NULL if there is no space.
 183  */
 184 static struct gs_tx_context *gs_alloc_tx_context(struct gs_can *dev)
 185 {
 186         int i = 0;
 187         unsigned long flags;
 188
 189         spin_lock_irqsave(&dev->tx_ctx_lock, flags);
 190
 191         for (; i < GS_MAX_TX_URBS; i++) {
 192                 if (dev->tx_context[i].echo_id == GS_MAX_TX_URBS) {
 193                         dev->tx_context[i].echo_id = i;
 194                         spin_unlock_irqrestore(&dev->tx_ctx_lock, flags);
 195                         return &dev->tx_context[i];
 196                 }
 197         }
 198
 199         spin_unlock_irqrestore(&dev->tx_ctx_lock, flags);
 200         return NULL;
 201 }
 202
 203 /* releases a tx context
 204  */
 205 static void gs_free_tx_context(struct gs_tx_context *txc)
 206 {
 207         txc->echo_id = GS_MAX_TX_URBS;
 208 }
 209
 210 /* Get a tx context by id.
 211  */
 212 static struct gs_tx_context *gs_get_tx_context(struct gs_can *dev, unsigned int id)
 213 {
 214         unsigned long flags;
 215
 216         if (id < GS_MAX_TX_URBS) {
 217                 spin_lock_irqsave(&dev->tx_ctx_lock, flags);
 218                 if (dev->tx_context[id].echo_id == id) {
 219                         spin_unlock_irqrestore(&dev->tx_ctx_lock, flags);
 220                         return &dev->tx_context[id];
 221                 }
 222                 spin_unlock_irqrestore(&dev->tx_ctx_lock, flags);
 223         }
 224         return NULL;
 225 }
 226
 227 static int gs_cmd_reset(struct gs_usb *gsusb, struct gs_can *gsdev)
 228 {
 229         struct gs_device_mode *dm;
 230         struct usb_interface *intf = gsdev->iface;
 231         int rc;
 232
 233         dm = kzalloc(sizeof(*dm), GFP_KERNEL);
 234         if (!dm)
 235                 return -ENOMEM;
 236
 237         dm->mode = GS_CAN_MODE_RESET;
 238
 239         rc = usb_control_msg(interface_to_usbdev(intf),
 240                              usb_sndctrlpipe(interface_to_usbdev(intf), 0),
 241                              GS_USB_BREQ_MODE,
 242                              USB_DIR_OUT|USB_TYPE_VENDOR|USB_RECIP_INTERFACE,
 243                              gsdev->channel,
 244                              0,
 245                              dm,
 246                              sizeof(*dm),
 247                              1000);
 248
 249         return rc;
 250 }
 251
 252 static void gs_update_state(struct gs_can *dev, struct can_frame *cf)
 253 {
 254         struct can_device_stats *can_stats = &dev->can.can_stats;
 255
 256         if (cf->can_id & CAN_ERR_RESTARTED) {
 257                 dev->can.state = CAN_STATE_ERROR_ACTIVE;
 258                 can_stats->restarts++;
 259         } else if (cf->can_id & CAN_ERR_BUSOFF) {
 260                 dev->can.state = CAN_STATE_BUS_OFF;
 261                 can_stats->bus_off++;
 262         } else if (cf->can_id & CAN_ERR_CRTL) {
 263                 if ((cf->data[1] & CAN_ERR_CRTL_TX_WARNING) ||
 264                     (cf->data[1] & CAN_ERR_CRTL_RX_WARNING)) {
 265                         dev->can.state = CAN_STATE_ERROR_WARNING;
 266                         can_stats->error_warning++;
 267                 } else if ((cf->data[1] & CAN_ERR_CRTL_TX_PASSIVE) ||
 268                            (cf->data[1] & CAN_ERR_CRTL_RX_PASSIVE)) {
 269                         dev->can.state = CAN_STATE_ERROR_PASSIVE;
 270                         can_stats->error_passive++;
 271                 } else {
 272                         dev->can.state = CAN_STATE_ERROR_ACTIVE;
 273                 }
 274         }
 275 }
 276
 277 static void gs_usb_recieve_bulk_callback(struct urb *urb)
 278 {
 279         struct gs_usb *usbcan = urb->context;
 280         struct gs_can *dev;
 281         struct net_device *netdev;
 282         int rc;
 283         struct net_device_stats *stats;
 284         struct gs_host_frame *hf = urb->transfer_buffer;
 285         struct gs_tx_context *txc;
 286         struct can_frame *cf;
 287         struct sk_buff *skb;
 288
 289         BUG_ON(!usbcan);
 290
 291         switch (urb->status) {
 292         case 0: /* success */
 293                 break;
 294         case -ENOENT:
 295         case -ESHUTDOWN:
 296                 return;
 297         default:
 298                 /* do not resubmit aborted urbs. eg: when device goes down */
 299                 return;
 300         }
 301
 302         /* device reports out of range channel id */
 303         if (hf->channel >= GS_MAX_INTF)
 304                 goto resubmit_urb;
 305
 306         dev = usbcan->canch[hf->channel];
 307
 308         netdev = dev->netdev;
 309         stats = &netdev->stats;
 310
 311         if (!netif_device_present(netdev))
 312                 return;
 313
 314         if (hf->echo_id == -1) { /* normal rx */
 315                 skb = alloc_can_skb(dev->netdev, &cf);
 316                 if (!skb)
 317                         return;
 318
 319                 cf->can_id = hf->can_id;
 320
 321                 cf->can_dlc = get_can_dlc(hf->can_dlc);
 322                 memcpy(cf->data, hf->data, 8);
 323
 324                 /* ERROR frames tell us information about the controller */
 325                 if (hf->can_id & CAN_ERR_FLAG)
 326                         gs_update_state(dev, cf);
 327
 328                 netdev->stats.rx_packets++;
 329                 netdev->stats.rx_bytes += hf->can_dlc;
 330
 331                 netif_rx(skb);
 332         } else { /* echo_id == hf->echo_id */
 333                 if (hf->echo_id >= GS_MAX_TX_URBS) {
 334                         netdev_err(netdev,
 335                                    "Unexpected out of range echo id %d\n",
 336                                    hf->echo_id);
 337                         goto resubmit_urb;
 338                 }
 339
 340                 netdev->stats.tx_packets++;
 341                 netdev->stats.tx_bytes += hf->can_dlc;
 342
 343                 txc = gs_get_tx_context(dev, hf->echo_id);
 344
 345                 /* bad devices send bad echo_ids. */
 346                 if (!txc) {
 347                         netdev_err(netdev,
 348                                    "Unexpected unused echo id %d\n",
 349                                    hf->echo_id);
 350                         goto resubmit_urb;
 351                 }
 352
 353                 can_get_echo_skb(netdev, hf->echo_id);
 354
 355                 gs_free_tx_context(txc);
 356
 357                 netif_wake_queue(netdev);
 358         }
 359
 360         if (hf->flags & GS_CAN_FLAG_OVERFLOW) {
 361                 skb = alloc_can_err_skb(netdev, &cf);
 362                 if (!skb)
 363                         goto resubmit_urb;
 364
 365                 cf->can_id |= CAN_ERR_CRTL;
 366                 cf->can_dlc = CAN_ERR_DLC;
 367                 cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
 368                 stats->rx_over_errors++;
 369                 stats->rx_errors++;
 370                 netif_rx(skb);
 371         }
 372
 373  resubmit_urb:
 374         usb_fill_bulk_urb(urb,
 375                           usbcan->udev,
 376                           usb_rcvbulkpipe(usbcan->udev, GSUSB_ENDPOINT_IN),
 377                           hf,
 378                           sizeof(struct gs_host_frame),
 379                           gs_usb_recieve_bulk_callback,
 380                           usbcan
 381                           );
 382
 383         rc = usb_submit_urb(urb, GFP_ATOMIC);
 384
 385         /* USB failure take down all interfaces */
 386         if (rc == -ENODEV) {
 387                 for (rc = 0; rc < GS_MAX_INTF; rc++) {
 388                         if (usbcan->canch[rc])
 389                                 netif_device_detach(usbcan->canch[rc]->netdev);
 390                 }
 391         }
 392 }
 393
 394 static int gs_usb_set_bittiming(struct net_device *netdev)
 395 {
 396         struct gs_can *dev = netdev_priv(netdev);
 397         struct can_bittiming *bt = &dev->can.bittiming;
 398         struct usb_interface *intf = dev->iface;
 399         int rc;
 400         struct gs_device_bittiming *dbt;
 401
 402         dbt = kmalloc(sizeof(*dbt), GFP_KERNEL);
 403         if (!dbt)
 404                 return -ENOMEM;
 405
 406         dbt->prop_seg = bt->prop_seg;
 407         dbt->phase_seg1 = bt->phase_seg1;
 408         dbt->phase_seg2 = bt->phase_seg2;
 409         dbt->sjw = bt->sjw;
 410         dbt->brp = bt->brp;
 411
 412         /* request bit timings */
 413         rc = usb_control_msg(interface_to_usbdev(intf),
 414                              usb_sndctrlpipe(interface_to_usbdev(intf), 0),
 415                              GS_USB_BREQ_BITTIMING,
 416                              USB_DIR_OUT|USB_TYPE_VENDOR|USB_RECIP_INTERFACE,
 417                              dev->channel,
 418                              0,
 419                              dbt,
 420                              sizeof(*dbt),
 421                              1000);
 422
 423         kfree(dbt);
 424
 425         if (rc < 0)
 426                 dev_err(netdev->dev.parent, "Couldn't set bittimings (err=%d)",
 427                         rc);
 428
 429         return rc;
 430 }
 431
 432 static void gs_usb_xmit_callback(struct urb *urb)
 433 {
 434         struct gs_tx_context *txc = urb->context;
 435         struct gs_can *dev = txc->dev;
 436         struct net_device *netdev = dev->netdev;
 437
 438         if (urb->status)
 439                 netdev_info(netdev, "usb xmit fail %d\n", txc->echo_id);
 440
 441         usb_free_coherent(urb->dev,
 442                           urb->transfer_buffer_length,
 443                           urb->transfer_buffer,
 444                           urb->transfer_dma);
 445
 446         atomic_dec(&dev->active_tx_urbs);
 447
 448         if (!netif_device_present(netdev))
 449                 return;
 450
 451         if (netif_queue_stopped(netdev))
 452                 netif_wake_queue(netdev);
 453 }
 454
 455 static netdev_tx_t gs_can_start_xmit(struct sk_buff *skb, struct net_device *netdev)
 456 {
 457         struct gs_can *dev = netdev_priv(netdev);
 458         struct net_device_stats *stats = &dev->netdev->stats;
 459         struct urb *urb;
 460         struct gs_host_frame *hf;
 461         struct can_frame *cf;
 462         int rc;
 463         unsigned int idx;
 464         struct gs_tx_context *txc;
 465
 466         if (can_dropped_invalid_skb(netdev, skb))
 467                 return NETDEV_TX_OK;
 468
 469         /* find an empty context to keep track of transmission */
 470         txc = gs_alloc_tx_context(dev);
 471         if (!txc)
 472                 return NETDEV_TX_BUSY;
 473
 474         /* create a URB, and a buffer for it */
 475         urb = usb_alloc_urb(0, GFP_ATOMIC);
 476         if (!urb) {
 477                 netdev_err(netdev, "No memory left for URB\n");
 478                 goto nomem_urb;
 479         }
 480
 481         hf = usb_alloc_coherent(dev->udev, sizeof(*hf), GFP_ATOMIC,
 482                                 &urb->transfer_dma);
 483         if (!hf) {
 484                 netdev_err(netdev, "No memory left for USB buffer\n");
 485                 goto nomem_hf;
 486         }
 487
 488         idx = txc->echo_id;
 489
 490         if (idx >= GS_MAX_TX_URBS) {
 491                 netdev_err(netdev, "Invalid tx context %d\n", idx);
 492                 goto badidx;
 493         }
 494
 495         hf->echo_id = idx;
 496         hf->channel = dev->channel;
 497
 498         cf = (struct can_frame *)skb->data;
 499
 500         hf->can_id = cf->can_id;
 501         hf->can_dlc = cf->can_dlc;
 502         memcpy(hf->data, cf->data, cf->can_dlc);
 503
 504         usb_fill_bulk_urb(urb, dev->udev,
 505                           usb_sndbulkpipe(dev->udev, GSUSB_ENDPOINT_OUT),
 506                           hf,
 507                           sizeof(*hf),
 508                           gs_usb_xmit_callback,
 509                           txc);
 510
 511         urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 512         usb_anchor_urb(urb, &dev->tx_submitted);
 513
 514         can_put_echo_skb(skb, netdev, idx);
 515
 516         atomic_inc(&dev->active_tx_urbs);
 517
 518         rc = usb_submit_urb(urb, GFP_ATOMIC);
 519         if (unlikely(rc)) {                     /* usb send failed */
 520                 atomic_dec(&dev->active_tx_urbs);
 521
 522                 can_free_echo_skb(netdev, idx);
 523                 gs_free_tx_context(txc);
 524
 525                 usb_unanchor_urb(urb);
 526                 usb_free_coherent(dev->udev,
 527                                   sizeof(*hf),
 528                                   hf,
 529                                   urb->transfer_dma);
 530
 531
 532                 if (rc == -ENODEV) {
 533                         netif_device_detach(netdev);
 534                 } else {
 535                         netdev_err(netdev, "usb_submit failed (err=%d)\n", rc);
 536                         stats->tx_dropped++;
 537                 }
 538         } else {
 539                 /* Slow down tx path */
 540                 if (atomic_read(&dev->active_tx_urbs) >= GS_MAX_TX_URBS)
 541                         netif_stop_queue(netdev);
 542         }
 543
 544         /* let usb core take care of this urb */
 545         usb_free_urb(urb);
 546
 547         return NETDEV_TX_OK;
 548
 549  badidx:
 550         usb_free_coherent(dev->udev,
 551                           sizeof(*hf),
 552                           hf,
 553                           urb->transfer_dma);
 554  nomem_hf:
 555         usb_free_urb(urb);
 556
 557  nomem_urb:
 558         gs_free_tx_context(txc);
 559         dev_kfree_skb(skb);
 560         stats->tx_dropped++;
 561         return NETDEV_TX_OK;
 562 }
 563
 564 static int gs_can_open(struct net_device *netdev)
 565 {
 566         struct gs_can *dev = netdev_priv(netdev);
 567         struct gs_usb *parent = dev->parent;
 568         int rc, i;
 569         struct gs_device_mode *dm;
 570         u32 ctrlmode;
 571
 572         rc = open_candev(netdev);
 573         if (rc)
 574                 return rc;
 575
 576         if (atomic_add_return(1, &parent->active_channels) == 1) {
 577                 for (i = 0; i < GS_MAX_RX_URBS; i++) {
 578                         struct urb *urb;
 579                         u8 *buf;
 580
 581                         /* alloc rx urb */
 582                         urb = usb_alloc_urb(0, GFP_KERNEL);
 583                         if (!urb) {
 584                                 netdev_err(netdev,
 585                                            "No memory left for URB\n");
 586                                 return -ENOMEM;
 587                         }
 588
 589                         /* alloc rx buffer */
 590                         buf = usb_alloc_coherent(dev->udev,
 591                                                  sizeof(struct gs_host_frame),
 592                                                  GFP_KERNEL,
 593                                                  &urb->transfer_dma);
 594                         if (!buf) {
 595                                 netdev_err(netdev,
 596                                            "No memory left for USB buffer\n");
 597                                 usb_free_urb(urb);
 598                                 return -ENOMEM;
 599                         }
 600
 601                         /* fill, anchor, and submit rx urb */
 602                         usb_fill_bulk_urb(urb,
 603                                           dev->udev,
 604                                           usb_rcvbulkpipe(dev->udev,
 605                                                           GSUSB_ENDPOINT_IN),
 606                                           buf,
 607                                           sizeof(struct gs_host_frame),
 608                                           gs_usb_recieve_bulk_callback,
 609                                           parent);
 610                         urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 611
 612                         usb_anchor_urb(urb, &parent->rx_submitted);
 613
 614                         rc = usb_submit_urb(urb, GFP_KERNEL);
 615                         if (rc) {
 616                                 if (rc == -ENODEV)
 617                                         netif_device_detach(dev->netdev);
 618
 619                                 netdev_err(netdev,
 620                                            "usb_submit failed (err=%d)\n",
 621                                            rc);
 622
 623                                 usb_unanchor_urb(urb);
 624                                 break;
 625                         }
 626
 627                         /* Drop reference,
 628                          * USB core will take care of freeing it
 629                          */
 630                         usb_free_urb(urb);
 631                 }
 632         }
 633
 634         dm = kmalloc(sizeof(*dm), GFP_KERNEL);
 635         if (!dm)
 636                 return -ENOMEM;
 637
 638         /* flags */
 639         ctrlmode = dev->can.ctrlmode;
 640         dm->flags = 0;
 641
 642         if (ctrlmode & CAN_CTRLMODE_LOOPBACK)
 643                 dm->flags |= GS_CAN_MODE_LOOP_BACK;
 644         else if (ctrlmode & CAN_CTRLMODE_LISTENONLY)
 645                 dm->flags |= GS_CAN_MODE_LISTEN_ONLY;
 646
 647         /* Controller is not allowed to retry TX
 648          * this mode is unavailable on atmels uc3c hardware
 649          */
 650         if (ctrlmode & CAN_CTRLMODE_ONE_SHOT)
 651                 dm->flags |= GS_CAN_MODE_ONE_SHOT;
 652
 653         if (ctrlmode & CAN_CTRLMODE_3_SAMPLES)
 654                 dm->flags |= GS_CAN_MODE_TRIPLE_SAMPLE;
 655
 656         /* finally start device */
 657         dm->mode = GS_CAN_MODE_START;
 658         rc = usb_control_msg(interface_to_usbdev(dev->iface),
 659                              usb_sndctrlpipe(interface_to_usbdev(dev->iface), 0),
 660                              GS_USB_BREQ_MODE,
 661                              USB_DIR_OUT|USB_TYPE_VENDOR|USB_RECIP_INTERFACE,
 662                              dev->channel,
 663                              0,
 664                              dm,
 665                              sizeof(*dm),
 666                              1000);
 667
 668         if (rc < 0) {
 669                 netdev_err(netdev, "Couldn't start device (err=%d)\n", rc);
 670                 kfree(dm);
 671                 return rc;
 672         }
 673
 674         kfree(dm);
 675
 676         dev->can.state = CAN_STATE_ERROR_ACTIVE;
 677
 678         if (!(dev->can.ctrlmode & CAN_CTRLMODE_LISTENONLY))
 679                 netif_start_queue(netdev);
 680
 681         return 0;
 682 }
 683
 684 static int gs_can_close(struct net_device *netdev)
 685 {
 686         int rc;
 687         struct gs_can *dev = netdev_priv(netdev);
 688         struct gs_usb *parent = dev->parent;
 689
 690         netif_stop_queue(netdev);
 691
 692         /* Stop polling */
 693         if (atomic_dec_and_test(&parent->active_channels))
 694                 usb_kill_anchored_urbs(&parent->rx_submitted);
 695
 696         /* Stop sending URBs */
 697         usb_kill_anchored_urbs(&dev->tx_submitted);
 698         atomic_set(&dev->active_tx_urbs, 0);
 699
 700         /* reset the device */
 701         rc = gs_cmd_reset(parent, dev);
 702         if (rc < 0)
 703                 netdev_warn(netdev, "Couldn't shutdown device (err=%d)", rc);
 704
 705         /* reset tx contexts */
 706         for (rc = 0; rc < GS_MAX_TX_URBS; rc++) {
 707                 dev->tx_context[rc].dev = dev;
 708                 dev->tx_context[rc].echo_id = GS_MAX_TX_URBS;
 709         }
 710
 711         /* close the netdev */
 712         close_candev(netdev);
 713
 714         return 0;
 715 }
 716
 717 static const struct net_device_ops gs_usb_netdev_ops = {
 718         .ndo_open = gs_can_open,
 719         .ndo_stop = gs_can_close,
 720         .ndo_start_xmit = gs_can_start_xmit,
 721         .ndo_change_mtu = can_change_mtu,
 722 };
 723
 724 static struct gs_can *gs_make_candev(unsigned int channel, struct usb_interface *intf)
 725 {
 726         struct gs_can *dev;
 727         struct net_device *netdev;
 728         int rc;
 729         struct gs_device_bt_const *bt_const;
 730
 731         bt_const = kmalloc(sizeof(*bt_const), GFP_KERNEL);
 732         if (!bt_const)
 733                 return ERR_PTR(-ENOMEM);
 734
 735         /* fetch bit timing constants */
 736         rc = usb_control_msg(interface_to_usbdev(intf),
 737                              usb_rcvctrlpipe(interface_to_usbdev(intf), 0),
 738                              GS_USB_BREQ_BT_CONST,
 739                              USB_DIR_IN|USB_TYPE_VENDOR|USB_RECIP_INTERFACE,
 740                              channel,
 741                              0,
 742                              bt_const,
 743                              sizeof(*bt_const),
 744                              1000);
 745
 746         if (rc < 0) {
 747                 dev_err(&intf->dev,
 748                         "Couldn't get bit timing const for channel (err=%d)\n",
 749                         rc);
 750                 kfree(bt_const);
 751                 return ERR_PTR(rc);
 752         }
 753
 754         /* create netdev */
 755         netdev = alloc_candev(sizeof(struct gs_can), GS_MAX_TX_URBS);
 756         if (!netdev) {
 757                 dev_err(&intf->dev, "Couldn't allocate candev\n");
 758                 kfree(bt_const);
 759                 return ERR_PTR(-ENOMEM);
 760         }
 761
 762         dev = netdev_priv(netdev);
 763
 764         netdev->netdev_ops = &gs_usb_netdev_ops;
 765
 766         netdev->flags |= IFF_ECHO; /* we support full roundtrip echo */
 767
 768         /* dev settup */
 769         strcpy(dev->bt_const.name, "gs_usb");
 770         dev->bt_const.tseg1_min = bt_const->tseg1_min;
 771         dev->bt_const.tseg1_max = bt_const->tseg1_max;
 772         dev->bt_const.tseg2_min = bt_const->tseg2_min;
 773         dev->bt_const.tseg2_max = bt_const->tseg2_max;
 774         dev->bt_const.sjw_max = bt_const->sjw_max;
 775         dev->bt_const.brp_min = bt_const->brp_min;
 776         dev->bt_const.brp_max = bt_const->brp_max;
 777         dev->bt_const.brp_inc = bt_const->brp_inc;
 778
 779         dev->udev = interface_to_usbdev(intf);
 780         dev->iface = intf;
 781         dev->netdev = netdev;
 782         dev->channel = channel;
 783
 784         init_usb_anchor(&dev->tx_submitted);
 785         atomic_set(&dev->active_tx_urbs, 0);
 786         spin_lock_init(&dev->tx_ctx_lock);
 787         for (rc = 0; rc < GS_MAX_TX_URBS; rc++) {
 788                 dev->tx_context[rc].dev = dev;
 789                 dev->tx_context[rc].echo_id = GS_MAX_TX_URBS;
 790         }
 791
 792         /* can settup */
 793         dev->can.state = CAN_STATE_STOPPED;
 794         dev->can.clock.freq = bt_const->fclk_can;
 795         dev->can.bittiming_const = &dev->bt_const;
 796         dev->can.do_set_bittiming = gs_usb_set_bittiming;
 797
 798         dev->can.ctrlmode_supported = 0;
 799
 800         if (bt_const->feature & GS_CAN_FEATURE_LISTEN_ONLY)
 801                 dev->can.ctrlmode_supported |= CAN_CTRLMODE_LISTENONLY;
 802
 803         if (bt_const->feature & GS_CAN_FEATURE_LOOP_BACK)
 804                 dev->can.ctrlmode_supported |= CAN_CTRLMODE_LOOPBACK;
 805
 806         if (bt_const->feature & GS_CAN_FEATURE_TRIPLE_SAMPLE)
 807                 dev->can.ctrlmode_supported |= CAN_CTRLMODE_3_SAMPLES;
 808
 809         if (bt_const->feature & GS_CAN_FEATURE_ONE_SHOT)
 810                 dev->can.ctrlmode_supported |= CAN_CTRLMODE_ONE_SHOT;
 811
 812         kfree(bt_const);
 813
 814         SET_NETDEV_DEV(netdev, &intf->dev);
 815
 816         rc = register_candev(dev->netdev);
 817         if (rc) {
 818                 free_candev(dev->netdev);
 819                 dev_err(&intf->dev, "Couldn't register candev (err=%d)\n", rc);
 820                 return ERR_PTR(rc);
 821         }
 822
 823         return dev;
 824 }
 825
 826 static void gs_destroy_candev(struct gs_can *dev)
 827 {
 828         unregister_candev(dev->netdev);
 829         free_candev(dev->netdev);
 830         usb_kill_anchored_urbs(&dev->tx_submitted);
 831         kfree(dev);
 832 }
 833
 834 static int gs_usb_probe(struct usb_interface *intf, const struct usb_device_id *id)
 835 {
 836         struct gs_usb *dev;
 837         int rc = -ENOMEM;
 838         unsigned int icount, i;
 839         struct gs_host_config *hconf;
 840         struct gs_device_config *dconf;
 841
 842         hconf = kmalloc(sizeof(*hconf), GFP_KERNEL);
 843         if (!hconf)
 844                 return -ENOMEM;
 845
 846         hconf->byte_order = 0x0000beef;
 847
 848         /* send host config */
 849         rc = usb_control_msg(interface_to_usbdev(intf),
 850                              usb_sndctrlpipe(interface_to_usbdev(intf), 0),
 851                              GS_USB_BREQ_HOST_FORMAT,
 852                              USB_DIR_OUT|USB_TYPE_VENDOR|USB_RECIP_INTERFACE,
 853                              1,
 854                              intf->altsetting[0].desc.bInterfaceNumber,
 855                              hconf,
 856                              sizeof(*hconf),
 857                              1000);
 858
 859         kfree(hconf);
 860
 861         if (rc < 0) {
 862                 dev_err(&intf->dev, "Couldn't send data format (err=%d)\n",
 863                         rc);
 864                 return rc;
 865         }
 866
 867         dconf = kmalloc(sizeof(*dconf), GFP_KERNEL);
 868         if (!dconf)
 869                 return -ENOMEM;
 870
 871         /* read device config */
 872         rc = usb_control_msg(interface_to_usbdev(intf),
 873                              usb_rcvctrlpipe(interface_to_usbdev(intf), 0),
 874                              GS_USB_BREQ_DEVICE_CONFIG,
 875                              USB_DIR_IN|USB_TYPE_VENDOR|USB_RECIP_INTERFACE,
 876                              1,
 877                              intf->altsetting[0].desc.bInterfaceNumber,
 878                              dconf,
 879                              sizeof(*dconf),
 880                              1000);
 881         if (rc < 0) {
 882                 dev_err(&intf->dev, "Couldn't get device config: (err=%d)\n",
 883                         rc);
 884
 885                 kfree(dconf);
 886
 887                 return rc;
 888         }
 889
 890         icount = dconf->icount+1;
 891
 892         kfree(dconf);
 893
 894         dev_info(&intf->dev, "Configuring for %d interfaces\n", icount);
 895
 896         if (icount > GS_MAX_INTF) {
 897                 dev_err(&intf->dev,
 898                         "Driver cannot handle more that %d CAN interfaces\n",
 899                         GS_MAX_INTF);
 900                 return -EINVAL;
 901         }
 902
 903         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 904         init_usb_anchor(&dev->rx_submitted);
 905
 906         atomic_set(&dev->active_channels, 0);
 907
 908         usb_set_intfdata(intf, dev);
 909         dev->udev = interface_to_usbdev(intf);
 910
 911         for (i = 0; i < icount; i++) {
 912                 dev->canch[i] = gs_make_candev(i, intf);
 913                 if (IS_ERR_OR_NULL(dev->canch[i])) {
 914                         /* on failure destroy previously created candevs */
 915                         icount = i;
 916                         for (i = 0; i < icount; i++) {
 917                                 gs_destroy_candev(dev->canch[i]);
 918                                 dev->canch[i] = NULL;
 919                         }
 920                         kfree(dev);
 921                         return rc;
 922                 }
 923                 dev->canch[i]->parent = dev;
 924         }
 925
 926         return 0;
 927 }
 928
 929 static void gs_usb_disconnect(struct usb_interface *intf)
 930 {
 931         unsigned i;
 932         struct gs_usb *dev = usb_get_intfdata(intf);
 933         usb_set_intfdata(intf, NULL);
 934
 935         if (!dev) {
 936                 dev_err(&intf->dev, "Disconnect (nodata)\n");
 937                 return;
 938         }
 939
 940         for (i = 0; i < GS_MAX_INTF; i++) {
 941                 struct gs_can *can = dev->canch[i];
 942
 943                 if (!can)
 944                         continue;
 945
 946                 gs_destroy_candev(can);
 947         }
 948
 949         usb_kill_anchored_urbs(&dev->rx_submitted);
 950 }
 951
 952 static const struct usb_device_id gs_usb_table[] = {
 953         {USB_DEVICE(USB_GSUSB_1_VENDOR_ID, USB_GSUSB_1_PRODUCT_ID)},
 954         {} /* Terminating entry */
 955 };
 956
 957 MODULE_DEVICE_TABLE(usb, gs_usb_table);
 958
 959 static struct usb_driver gs_usb_driver = {
 960         .name       = "gs_usb",
 961         .probe      = gs_usb_probe,
 962         .disconnect = gs_usb_disconnect,
 963         .id_table   = gs_usb_table,
 964 };
 965
 966 module_usb_driver(gs_usb_driver);
 967
 968 MODULE_AUTHOR("Maximilian Schneider <mws@schneidersoft.net>");
 969 MODULE_DESCRIPTION(
 970 "Socket CAN device driver for Geschwister Schneider Technologie-, "
 971 "Entwicklungs- und Vertriebs UG. USB2.0 to CAN interfaces.");
 972 MODULE_LICENSE("GPL v2");