drivers/net/can/usb/ucan.c

   1 // SPDX-License-Identifier: GPL-2.0
   2
   3 /* Driver for Theobroma Systems UCAN devices, Protocol Version 3
   4  *
   5  * Copyright (C) 2018 Theobroma Systems Design und Consulting GmbH
   6  *
   7  *
   8  * General Description:
   9  *
  10  * The USB Device uses three Endpoints:
  11  *
  12  *   CONTROL Endpoint: Is used the setup the device (start, stop,
  13  *   info, configure).
  14  *
  15  *   IN Endpoint: The device sends CAN Frame Messages and Device
  16  *   Information using the IN endpoint.
  17  *
  18  *   OUT Endpoint: The driver sends configuration requests, and CAN
  19  *   Frames on the out endpoint.
  20  *
  21  * Error Handling:
  22  *
  23  *   If error reporting is turned on the device encodes error into CAN
  24  *   error frames (see uapi/linux/can/error.h) and sends it using the
  25  *   IN Endpoint. The driver updates statistics and forward it.
  26  */
  27
  28 #include <linux/can.h>
  29 #include <linux/can/dev.h>
  30 #include <linux/can/error.h>
  31 #include <linux/module.h>
  32 #include <linux/netdevice.h>
  33 #include <linux/signal.h>
  34 #include <linux/skbuff.h>
  35 #include <linux/slab.h>
  36 #include <linux/usb.h>
  37
  38 #include <linux/can.h>
  39 #include <linux/can/dev.h>
  40 #include <linux/can/error.h>
  41
  42 #define UCAN_DRIVER_NAME "ucan"
  43 #define UCAN_MAX_RX_URBS 8
  44 /* the CAN controller needs a while to enable/disable the bus */
  45 #define UCAN_USB_CTL_PIPE_TIMEOUT 1000
  46 /* this driver currently supports protocol version 3 only */
  47 #define UCAN_PROTOCOL_VERSION_MIN 3
  48 #define UCAN_PROTOCOL_VERSION_MAX 3
  49
  50 /* UCAN Message Definitions
  51  * ------------------------
  52  *
  53  *  ucan_message_out_t and ucan_message_in_t define the messages
  54  *  transmitted on the OUT and IN endpoint.
  55  *
  56  *  Multibyte fields are transmitted with little endianness
  57  *
  58  *  INTR Endpoint: a single uint32_t storing the current space in the fifo
  59  *
  60  *  OUT Endpoint: single message of type ucan_message_out_t is
  61  *    transmitted on the out endpoint
  62  *
  63  *  IN Endpoint: multiple messages ucan_message_in_t concateted in
  64  *    the following way:
  65  *
  66  *      m[n].len <=> the length if message n(including the header in bytes)
  67  *      m[n] is is aligned to a 4 byte boundary, hence
  68  *        offset(m[0])   := 0;
  69  *        offset(m[n+1]) := offset(m[n]) + (m[n].len + 3) & 3
  70  *
  71  *      this implies that
  72  *        offset(m[n]) % 4 <=> 0
  73  */
  74
  75 /* Device Global Commands */
  76 enum {
  77         UCAN_DEVICE_GET_FW_STRING = 0,
  78 };
  79
  80 /* UCAN Commands */
  81 enum {
  82         /* start the can transceiver - val defines the operation mode */
  83         UCAN_COMMAND_START = 0,
  84         /* cancel pending transmissions and stop the can transceiver */
  85         UCAN_COMMAND_STOP = 1,
  86         /* send can transceiver into low-power sleep mode */
  87         UCAN_COMMAND_SLEEP = 2,
  88         /* wake up can transceiver from low-power sleep mode */
  89         UCAN_COMMAND_WAKEUP = 3,
  90         /* reset the can transceiver */
  91         UCAN_COMMAND_RESET = 4,
  92         /* get piece of info from the can transceiver - subcmd defines what
  93          * piece
  94          */
  95         UCAN_COMMAND_GET = 5,
  96         /* clear or disable hardware filter - subcmd defines which of the two */
  97         UCAN_COMMAND_FILTER = 6,
  98         /* Setup bittiming */
  99         UCAN_COMMAND_SET_BITTIMING = 7,
 100         /* recover from bus-off state */
 101         UCAN_COMMAND_RESTART = 8,
 102 };
 103
 104 /* UCAN_COMMAND_START and UCAN_COMMAND_GET_INFO operation modes (bitmap).
 105  * Undefined bits must be set to 0.
 106  */
 107 enum {
 108         UCAN_MODE_LOOPBACK = BIT(0),
 109         UCAN_MODE_SILENT = BIT(1),
 110         UCAN_MODE_3_SAMPLES = BIT(2),
 111         UCAN_MODE_ONE_SHOT = BIT(3),
 112         UCAN_MODE_BERR_REPORT = BIT(4),
 113 };
 114
 115 /* UCAN_COMMAND_GET subcommands */
 116 enum {
 117         UCAN_COMMAND_GET_INFO = 0,
 118         UCAN_COMMAND_GET_PROTOCOL_VERSION = 1,
 119 };
 120
 121 /* UCAN_COMMAND_FILTER subcommands */
 122 enum {
 123         UCAN_FILTER_CLEAR = 0,
 124         UCAN_FILTER_DISABLE = 1,
 125         UCAN_FILTER_ENABLE = 2,
 126 };
 127
 128 /* OUT endpoint message types */
 129 enum {
 130         UCAN_OUT_TX = 2,     /* transmit a CAN frame */
 131 };
 132
 133 /* IN endpoint message types */
 134 enum {
 135         UCAN_IN_TX_COMPLETE = 1,  /* CAN frame transmission completed */
 136         UCAN_IN_RX = 2,           /* CAN frame received */
 137 };
 138
 139 struct ucan_ctl_cmd_start {
 140         __le16 mode;         /* OR-ing any of UCAN_MODE_* */
 141 } __packed;
 142
 143 struct ucan_ctl_cmd_set_bittiming {
 144         __le32 tq;           /* Time quanta (TQ) in nanoseconds */
 145         __le16 brp;          /* TQ Prescaler */
 146         __le16 sample_point; /* Samplepoint on tenth percent */
 147         u8 prop_seg;         /* Propagation segment in TQs */
 148         u8 phase_seg1;       /* Phase buffer segment 1 in TQs */
 149         u8 phase_seg2;       /* Phase buffer segment 2 in TQs */
 150         u8 sjw;              /* Synchronisation jump width in TQs */
 151 } __packed;
 152
 153 struct ucan_ctl_cmd_device_info {
 154         __le32 freq;         /* Clock Frequency for tq generation */
 155         u8 tx_fifo;          /* Size of the transmission fifo */
 156         u8 sjw_max;          /* can_bittiming fields... */
 157         u8 tseg1_min;
 158         u8 tseg1_max;
 159         u8 tseg2_min;
 160         u8 tseg2_max;
 161         __le16 brp_inc;
 162         __le32 brp_min;
 163         __le32 brp_max;      /* ...can_bittiming fields */
 164         __le16 ctrlmodes;    /* supported control modes */
 165         __le16 hwfilter;     /* Number of HW filter banks */
 166         __le16 rxmboxes;     /* Number of receive Mailboxes */
 167 } __packed;
 168
 169 struct ucan_ctl_cmd_get_protocol_version {
 170         __le32 version;
 171 } __packed;
 172
 173 union ucan_ctl_payload {
 174         /* Setup Bittiming
 175          * bmRequest == UCAN_COMMAND_START
 176          */
 177         struct ucan_ctl_cmd_start cmd_start;
 178         /* Setup Bittiming
 179          * bmRequest == UCAN_COMMAND_SET_BITTIMING
 180          */
 181         struct ucan_ctl_cmd_set_bittiming cmd_set_bittiming;
 182         /* Get Device Information
 183          * bmRequest == UCAN_COMMAND_GET; wValue = UCAN_COMMAND_GET_INFO
 184          */
 185         struct ucan_ctl_cmd_device_info cmd_get_device_info;
 186         /* Get Protocol Version
 187          * bmRequest == UCAN_COMMAND_GET;
 188          * wValue = UCAN_COMMAND_GET_PROTOCOL_VERSION
 189          */
 190         struct ucan_ctl_cmd_get_protocol_version cmd_get_protocol_version;
 191
 192         u8 raw[128];
 193 } __packed;
 194
 195 enum {
 196         UCAN_TX_COMPLETE_SUCCESS = BIT(0),
 197 };
 198
 199 /* Transmission Complete within ucan_message_in */
 200 struct ucan_tx_complete_entry_t {
 201         u8 echo_index;
 202         u8 flags;
 203 } __packed __aligned(0x2);
 204
 205 /* CAN Data message format within ucan_message_in/out */
 206 struct ucan_can_msg {
 207         /* note DLC is computed by
 208          *    msg.len - sizeof (msg.len)
 209          *            - sizeof (msg.type)
 210          *            - sizeof (msg.can_msg.id)
 211          */
 212         __le32 id;
 213
 214         union {
 215                 u8 data[CAN_MAX_DLEN];  /* Data of CAN frames */
 216                 u8 dlc;                 /* RTR dlc */
 217         };
 218 } __packed;
 219
 220 /* OUT Endpoint, outbound messages */
 221 struct ucan_message_out {
 222         __le16 len; /* Length of the content include header */
 223         u8 type;    /* UCAN_OUT_TX and friends */
 224         u8 subtype; /* command sub type */
 225
 226         union {
 227                 /* Transmit CAN frame
 228                  * (type == UCAN_TX) && ((msg.can_msg.id & CAN_RTR_FLAG) == 0)
 229                  * subtype stores the echo id
 230                  */
 231                 struct ucan_can_msg can_msg;
 232         } msg;
 233 } __packed __aligned(0x4);
 234
 235 /* IN Endpoint, inbound messages */
 236 struct ucan_message_in {
 237         __le16 len; /* Length of the content include header */
 238         u8 type;    /* UCAN_IN_RX and friends */
 239         u8 subtype; /* command sub type */
 240
 241         union {
 242                 /* CAN Frame received
 243                  * (type == UCAN_IN_RX)
 244                  * && ((msg.can_msg.id & CAN_RTR_FLAG) == 0)
 245                  */
 246                 struct ucan_can_msg can_msg;
 247
 248                 /* CAN transmission complete
 249                  * (type == UCAN_IN_TX_COMPLETE)
 250                  */
 251                 struct ucan_tx_complete_entry_t can_tx_complete_msg[0];
 252         } __aligned(0x4) msg;
 253 } __packed;
 254
 255 /* Macros to calculate message lengths */
 256 #define UCAN_OUT_HDR_SIZE offsetof(struct ucan_message_out, msg)
 257
 258 #define UCAN_IN_HDR_SIZE offsetof(struct ucan_message_in, msg)
 259 #define UCAN_IN_LEN(member) (UCAN_OUT_HDR_SIZE + sizeof(member))
 260
 261 struct ucan_priv;
 262
 263 /* Context Information for transmission URBs */
 264 struct ucan_urb_context {
 265         struct ucan_priv *up;
 266         u8 dlc;
 267         bool allocated;
 268 };
 269
 270 /* Information reported by the USB device */
 271 struct ucan_device_info {
 272         struct can_bittiming_const bittiming_const;
 273         u8 tx_fifo;
 274 };
 275
 276 /* Driver private data */
 277 struct ucan_priv {
 278         /* must be the first member */
 279         struct can_priv can;
 280
 281         /* linux USB device structures */
 282         struct usb_device *udev;
 283         struct usb_interface *intf;
 284         struct net_device *netdev;
 285
 286         /* lock for can->echo_skb (used around
 287          * can_put/get/free_echo_skb
 288          */
 289         spinlock_t echo_skb_lock;
 290
 291         /* usb device information information */
 292         u8 intf_index;
 293         u8 in_ep_addr;
 294         u8 out_ep_addr;
 295         u16 in_ep_size;
 296
 297         /* transmission and reception buffers */
 298         struct usb_anchor rx_urbs;
 299         struct usb_anchor tx_urbs;
 300
 301         union ucan_ctl_payload *ctl_msg_buffer;
 302         struct ucan_device_info device_info;
 303
 304         /* transmission control information and locks */
 305         spinlock_t context_lock;
 306         unsigned int available_tx_urbs;
 307         struct ucan_urb_context *context_array;
 308 };
 309
 310 static u8 ucan_get_can_dlc(struct ucan_can_msg *msg, u16 len)
 311 {
 312         if (le32_to_cpu(msg->id) & CAN_RTR_FLAG)
 313                 return get_can_dlc(msg->dlc);
 314         else
 315                 return get_can_dlc(len - (UCAN_IN_HDR_SIZE + sizeof(msg->id)));
 316 }
 317
 318 static void ucan_release_context_array(struct ucan_priv *up)
 319 {
 320         if (!up->context_array)
 321                 return;
 322
 323         /* lock is not needed because, driver is currently opening or closing */
 324         up->available_tx_urbs = 0;
 325
 326         kfree(up->context_array);
 327         up->context_array = NULL;
 328 }
 329
 330 static int ucan_alloc_context_array(struct ucan_priv *up)
 331 {
 332         int i;
 333
 334         /* release contexts if any */
 335         ucan_release_context_array(up);
 336
 337         up->context_array = kcalloc(up->device_info.tx_fifo,
 338                                     sizeof(*up->context_array),
 339                                     GFP_KERNEL);
 340         if (!up->context_array) {
 341                 netdev_err(up->netdev,
 342                            "Not enough memory to allocate tx contexts\n");
 343                 return -ENOMEM;
 344         }
 345
 346         for (i = 0; i < up->device_info.tx_fifo; i++) {
 347                 up->context_array[i].allocated = false;
 348                 up->context_array[i].up = up;
 349         }
 350
 351         /* lock is not needed because, driver is currently opening */
 352         up->available_tx_urbs = up->device_info.tx_fifo;
 353
 354         return 0;
 355 }
 356
 357 static struct ucan_urb_context *ucan_alloc_context(struct ucan_priv *up)
 358 {
 359         int i;
 360         unsigned long flags;
 361         struct ucan_urb_context *ret = NULL;
 362
 363         if (WARN_ON_ONCE(!up->context_array))
 364                 return NULL;
 365
 366         /* execute context operation atomically */
 367         spin_lock_irqsave(&up->context_lock, flags);
 368
 369         for (i = 0; i < up->device_info.tx_fifo; i++) {
 370                 if (!up->context_array[i].allocated) {
 371                         /* update context */
 372                         ret = &up->context_array[i];
 373                         up->context_array[i].allocated = true;
 374
 375                         /* stop queue if necessary */
 376                         up->available_tx_urbs--;
 377                         if (!up->available_tx_urbs)
 378                                 netif_stop_queue(up->netdev);
 379
 380                         break;
 381                 }
 382         }
 383
 384         spin_unlock_irqrestore(&up->context_lock, flags);
 385         return ret;
 386 }
 387
 388 static bool ucan_release_context(struct ucan_priv *up,
 389                                  struct ucan_urb_context *ctx)
 390 {
 391         unsigned long flags;
 392         bool ret = false;
 393
 394         if (WARN_ON_ONCE(!up->context_array))
 395                 return false;
 396
 397         /* execute context operation atomically */
 398         spin_lock_irqsave(&up->context_lock, flags);
 399
 400         /* context was not allocated, maybe the device sent garbage */
 401         if (ctx->allocated) {
 402                 ctx->allocated = false;
 403
 404                 /* check if the queue needs to be woken */
 405                 if (!up->available_tx_urbs)
 406                         netif_wake_queue(up->netdev);
 407                 up->available_tx_urbs++;
 408
 409                 ret = true;
 410         }
 411
 412         spin_unlock_irqrestore(&up->context_lock, flags);
 413         return ret;
 414 }
 415
 416 static int ucan_ctrl_command_out(struct ucan_priv *up,
 417                                  u8 cmd, u16 subcmd, u16 datalen)
 418 {
 419         return usb_control_msg(up->udev,
 420                                usb_sndctrlpipe(up->udev, 0),
 421                                cmd,
 422                                USB_DIR_OUT | USB_TYPE_VENDOR |
 423                                                 USB_RECIP_INTERFACE,
 424                                subcmd,
 425                                up->intf_index,
 426                                up->ctl_msg_buffer,
 427                                datalen,
 428                                UCAN_USB_CTL_PIPE_TIMEOUT);
 429 }
 430
 431 static int ucan_device_request_in(struct ucan_priv *up,
 432                                   u8 cmd, u16 subcmd, u16 datalen)
 433 {
 434         return usb_control_msg(up->udev,
 435                                usb_rcvctrlpipe(up->udev, 0),
 436                                cmd,
 437                                USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
 438                                subcmd,
 439                                0,
 440                                up->ctl_msg_buffer,
 441                                datalen,
 442                                UCAN_USB_CTL_PIPE_TIMEOUT);
 443 }
 444
 445 /* Parse the device information structure reported by the device and
 446  * setup private variables accordingly
 447  */
 448 static void ucan_parse_device_info(struct ucan_priv *up,
 449                                    struct ucan_ctl_cmd_device_info *device_info)
 450 {
 451         struct can_bittiming_const *bittiming =
 452                 &up->device_info.bittiming_const;
 453         u16 ctrlmodes;
 454
 455         /* store the data */
 456         up->can.clock.freq = le32_to_cpu(device_info->freq);
 457         up->device_info.tx_fifo = device_info->tx_fifo;
 458         strcpy(bittiming->name, "ucan");
 459         bittiming->tseg1_min = device_info->tseg1_min;
 460         bittiming->tseg1_max = device_info->tseg1_max;
 461         bittiming->tseg2_min = device_info->tseg2_min;
 462         bittiming->tseg2_max = device_info->tseg2_max;
 463         bittiming->sjw_max = device_info->sjw_max;
 464         bittiming->brp_min = le32_to_cpu(device_info->brp_min);
 465         bittiming->brp_max = le32_to_cpu(device_info->brp_max);
 466         bittiming->brp_inc = le16_to_cpu(device_info->brp_inc);
 467
 468         ctrlmodes = le16_to_cpu(device_info->ctrlmodes);
 469
 470         up->can.ctrlmode_supported = 0;
 471
 472         if (ctrlmodes & UCAN_MODE_LOOPBACK)
 473                 up->can.ctrlmode_supported |= CAN_CTRLMODE_LOOPBACK;
 474         if (ctrlmodes & UCAN_MODE_SILENT)
 475                 up->can.ctrlmode_supported |= CAN_CTRLMODE_LISTENONLY;
 476         if (ctrlmodes & UCAN_MODE_3_SAMPLES)
 477                 up->can.ctrlmode_supported |= CAN_CTRLMODE_3_SAMPLES;
 478         if (ctrlmodes & UCAN_MODE_ONE_SHOT)
 479                 up->can.ctrlmode_supported |= CAN_CTRLMODE_ONE_SHOT;
 480         if (ctrlmodes & UCAN_MODE_BERR_REPORT)
 481                 up->can.ctrlmode_supported |= CAN_CTRLMODE_BERR_REPORTING;
 482 }
 483
 484 /* Handle a CAN error frame that we have received from the device.
 485  * Returns true if the can state has changed.
 486  */
 487 static bool ucan_handle_error_frame(struct ucan_priv *up,
 488                                     struct ucan_message_in *m,
 489                                     canid_t canid)
 490 {
 491         enum can_state new_state = up->can.state;
 492         struct net_device_stats *net_stats = &up->netdev->stats;
 493         struct can_device_stats *can_stats = &up->can.can_stats;
 494
 495         if (canid & CAN_ERR_LOSTARB)
 496                 can_stats->arbitration_lost++;
 497
 498         if (canid & CAN_ERR_BUSERROR)
 499                 can_stats->bus_error++;
 500
 501         if (canid & CAN_ERR_ACK)
 502                 net_stats->tx_errors++;
 503
 504         if (canid & CAN_ERR_BUSOFF)
 505                 new_state = CAN_STATE_BUS_OFF;
 506
 507         /* controller problems, details in data[1] */
 508         if (canid & CAN_ERR_CRTL) {
 509                 u8 d1 = m->msg.can_msg.data[1];
 510
 511                 if (d1 & CAN_ERR_CRTL_RX_OVERFLOW)
 512                         net_stats->rx_over_errors++;
 513
 514                 /* controller state bits: if multiple are set the worst wins */
 515                 if (d1 & CAN_ERR_CRTL_ACTIVE)
 516                         new_state = CAN_STATE_ERROR_ACTIVE;
 517
 518                 if (d1 & (CAN_ERR_CRTL_RX_WARNING | CAN_ERR_CRTL_TX_WARNING))
 519                         new_state = CAN_STATE_ERROR_WARNING;
 520
 521                 if (d1 & (CAN_ERR_CRTL_RX_PASSIVE | CAN_ERR_CRTL_TX_PASSIVE))
 522                         new_state = CAN_STATE_ERROR_PASSIVE;
 523         }
 524
 525         /* protocol error, details in data[2] */
 526         if (canid & CAN_ERR_PROT) {
 527                 u8 d2 = m->msg.can_msg.data[2];
 528
 529                 if (d2 & CAN_ERR_PROT_TX)
 530                         net_stats->tx_errors++;
 531                 else
 532                         net_stats->rx_errors++;
 533         }
 534
 535         /* no state change - we are done */
 536         if (up->can.state == new_state)
 537                 return false;
 538
 539         /* we switched into a better state */
 540         if (up->can.state > new_state) {
 541                 up->can.state = new_state;
 542                 return true;
 543         }
 544
 545         /* we switched into a worse state */
 546         up->can.state = new_state;
 547         switch (new_state) {
 548         case CAN_STATE_BUS_OFF:
 549                 can_stats->bus_off++;
 550                 can_bus_off(up->netdev);
 551                 break;
 552         case CAN_STATE_ERROR_PASSIVE:
 553                 can_stats->error_passive++;
 554                 break;
 555         case CAN_STATE_ERROR_WARNING:
 556                 can_stats->error_warning++;
 557                 break;
 558         default:
 559                 break;
 560         }
 561         return true;
 562 }
 563
 564 /* Callback on reception of a can frame via the IN endpoint
 565  *
 566  * This function allocates an skb and transferres it to the Linux
 567  * network stack
 568  */
 569 static void ucan_rx_can_msg(struct ucan_priv *up, struct ucan_message_in *m)
 570 {
 571         int len;
 572         canid_t canid;
 573         struct can_frame *cf;
 574         struct sk_buff *skb;
 575         struct net_device_stats *stats = &up->netdev->stats;
 576
 577         /* get the contents of the length field */
 578         len = le16_to_cpu(m->len);
 579
 580         /* check sanity */
 581         if (len < UCAN_IN_HDR_SIZE + sizeof(m->msg.can_msg.id)) {
 582                 netdev_warn(up->netdev, "invalid input message len: %d\n", len);
 583                 return;
 584         }
 585
 586         /* handle error frames */
 587         canid = le32_to_cpu(m->msg.can_msg.id);
 588         if (canid & CAN_ERR_FLAG) {
 589                 bool busstate_changed = ucan_handle_error_frame(up, m, canid);
 590
 591                 /* if berr-reporting is off only state changes get through */
 592                 if (!(up->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING) &&
 593                     !busstate_changed)
 594                         return;
 595         } else {
 596                 canid_t canid_mask;
 597                 /* compute the mask for canid */
 598                 canid_mask = CAN_RTR_FLAG;
 599                 if (canid & CAN_EFF_FLAG)
 600                         canid_mask |= CAN_EFF_MASK | CAN_EFF_FLAG;
 601                 else
 602                         canid_mask |= CAN_SFF_MASK;
 603
 604                 if (canid & ~canid_mask)
 605                         netdev_warn(up->netdev,
 606                                     "unexpected bits set (canid %x, mask %x)",
 607                                     canid, canid_mask);
 608
 609                 canid &= canid_mask;
 610         }
 611
 612         /* allocate skb */
 613         skb = alloc_can_skb(up->netdev, &cf);
 614         if (!skb)
 615                 return;
 616
 617         /* fill the can frame */
 618         cf->can_id = canid;
 619
 620         /* compute DLC taking RTR_FLAG into account */
 621         cf->can_dlc = ucan_get_can_dlc(&m->msg.can_msg, len);
 622
 623         /* copy the payload of non RTR frames */
 624         if (!(cf->can_id & CAN_RTR_FLAG) || (cf->can_id & CAN_ERR_FLAG))
 625                 memcpy(cf->data, m->msg.can_msg.data, cf->can_dlc);
 626
 627         /* don't count error frames as real packets */
 628         stats->rx_packets++;
 629         stats->rx_bytes += cf->can_dlc;
 630
 631         /* pass it to Linux */
 632         netif_rx(skb);
 633 }
 634
 635 /* callback indicating completed transmission */
 636 static void ucan_tx_complete_msg(struct ucan_priv *up,
 637                                  struct ucan_message_in *m)
 638 {
 639         unsigned long flags;
 640         u16 count, i;
 641         u8 echo_index, dlc;
 642         u16 len = le16_to_cpu(m->len);
 643
 644         struct ucan_urb_context *context;
 645
 646         if (len < UCAN_IN_HDR_SIZE || (len % 2 != 0)) {
 647                 netdev_err(up->netdev, "invalid tx complete length\n");
 648                 return;
 649         }
 650
 651         count = (len - UCAN_IN_HDR_SIZE) / 2;
 652         for (i = 0; i < count; i++) {
 653                 /* we did not submit such echo ids */
 654                 echo_index = m->msg.can_tx_complete_msg[i].echo_index;
 655                 if (echo_index >= up->device_info.tx_fifo) {
 656                         up->netdev->stats.tx_errors++;
 657                         netdev_err(up->netdev,
 658                                    "invalid echo_index %d received\n",
 659                                    echo_index);
 660                         continue;
 661                 }
 662
 663                 /* gather information from the context */
 664                 context = &up->context_array[echo_index];
 665                 dlc = READ_ONCE(context->dlc);
 666
 667                 /* Release context and restart queue if necessary.
 668                  * Also check if the context was allocated
 669                  */
 670                 if (!ucan_release_context(up, context))
 671                         continue;
 672
 673                 spin_lock_irqsave(&up->echo_skb_lock, flags);
 674                 if (m->msg.can_tx_complete_msg[i].flags &
 675                     UCAN_TX_COMPLETE_SUCCESS) {
 676                         /* update statistics */
 677                         up->netdev->stats.tx_packets++;
 678                         up->netdev->stats.tx_bytes += dlc;
 679                         can_get_echo_skb(up->netdev, echo_index);
 680                 } else {
 681                         up->netdev->stats.tx_dropped++;
 682                         can_free_echo_skb(up->netdev, echo_index);
 683                 }
 684                 spin_unlock_irqrestore(&up->echo_skb_lock, flags);
 685         }
 686 }
 687
 688 /* callback on reception of a USB message */
 689 static void ucan_read_bulk_callback(struct urb *urb)
 690 {
 691         int ret;
 692         int pos;
 693         struct ucan_priv *up = urb->context;
 694         struct net_device *netdev = up->netdev;
 695         struct ucan_message_in *m;
 696
 697         /* the device is not up and the driver should not receive any
 698          * data on the bulk in pipe
 699          */
 700         if (WARN_ON(!up->context_array)) {
 701                 usb_free_coherent(up->udev,
 702                                   up->in_ep_size,
 703                                   urb->transfer_buffer,
 704                                   urb->transfer_dma);
 705                 return;
 706         }
 707
 708         /* check URB status */
 709         switch (urb->status) {
 710         case 0:
 711                 break;
 712         case -ENOENT:
 713         case -EPIPE:
 714         case -EPROTO:
 715         case -ESHUTDOWN:
 716         case -ETIME:
 717                 /* urb is not resubmitted -> free dma data */
 718                 usb_free_coherent(up->udev,
 719                                   up->in_ep_size,
 720                                   urb->transfer_buffer,
 721                                   urb->transfer_dma);
 722                 netdev_dbg(up->netdev, "not resumbmitting urb; status: %d\n",
 723                            urb->status);
 724                 return;
 725         default:
 726                 goto resubmit;
 727         }
 728
 729         /* sanity check */
 730         if (!netif_device_present(netdev))
 731                 return;
 732
 733         /* iterate over input */
 734         pos = 0;
 735         while (pos < urb->actual_length) {
 736                 int len;
 737
 738                 /* check sanity (length of header) */
 739                 if ((urb->actual_length - pos) < UCAN_IN_HDR_SIZE) {
 740                         netdev_warn(up->netdev,
 741                                     "invalid message (short; no hdr; l:%d)\n",
 742                                     urb->actual_length);
 743                         goto resubmit;
 744                 }
 745
 746                 /* setup the message address */
 747                 m = (struct ucan_message_in *)
 748                         ((u8 *)urb->transfer_buffer + pos);
 749                 len = le16_to_cpu(m->len);
 750
 751                 /* check sanity (length of content) */
 752                 if (urb->actual_length - pos < len) {
 753                         netdev_warn(up->netdev,
 754                                     "invalid message (short; no data; l:%d)\n",
 755                                     urb->actual_length);
 756                         print_hex_dump(KERN_WARNING,
 757                                        "raw data: ",
 758                                        DUMP_PREFIX_ADDRESS,
 759                                        16,
 760                                        1,
 761                                        urb->transfer_buffer,
 762                                        urb->actual_length,
 763                                        true);
 764
 765                         goto resubmit;
 766                 }
 767
 768                 switch (m->type) {
 769                 case UCAN_IN_RX:
 770                         ucan_rx_can_msg(up, m);
 771                         break;
 772                 case UCAN_IN_TX_COMPLETE:
 773                         ucan_tx_complete_msg(up, m);
 774                         break;
 775                 default:
 776                         netdev_warn(up->netdev,
 777                                     "invalid message (type; t:%d)\n",
 778                                     m->type);
 779                         break;
 780                 }
 781
 782                 /* proceed to next message */
 783                 pos += len;
 784                 /* align to 4 byte boundary */
 785                 pos = round_up(pos, 4);
 786         }
 787
 788 resubmit:
 789         /* resubmit urb when done */
 790         usb_fill_bulk_urb(urb, up->udev,
 791                           usb_rcvbulkpipe(up->udev,
 792                                           up->in_ep_addr),
 793                           urb->transfer_buffer,
 794                           up->in_ep_size,
 795                           ucan_read_bulk_callback,
 796                           up);
 797
 798         usb_anchor_urb(urb, &up->rx_urbs);
 799         ret = usb_submit_urb(urb, GFP_ATOMIC);
 800
 801         if (ret < 0) {
 802                 netdev_err(up->netdev,
 803                            "failed resubmitting read bulk urb: %d\n",
 804                            ret);
 805
 806                 usb_unanchor_urb(urb);
 807                 usb_free_coherent(up->udev,
 808                                   up->in_ep_size,
 809                                   urb->transfer_buffer,
 810                                   urb->transfer_dma);
 811
 812                 if (ret == -ENODEV)
 813                         netif_device_detach(netdev);
 814         }
 815 }
 816
 817 /* callback after transmission of a USB message */
 818 static void ucan_write_bulk_callback(struct urb *urb)
 819 {
 820         unsigned long flags;
 821         struct ucan_priv *up;
 822         struct ucan_urb_context *context = urb->context;
 823
 824         /* get the urb context */
 825         if (WARN_ON_ONCE(!context))
 826                 return;
 827
 828         /* free up our allocated buffer */
 829         usb_free_coherent(urb->dev,
 830                           sizeof(struct ucan_message_out),
 831                           urb->transfer_buffer,
 832                           urb->transfer_dma);
 833
 834         up = context->up;
 835         if (WARN_ON_ONCE(!up))
 836                 return;
 837
 838         /* sanity check */
 839         if (!netif_device_present(up->netdev))
 840                 return;
 841
 842         /* transmission failed (USB - the device will not send a TX complete) */
 843         if (urb->status) {
 844                 netdev_warn(up->netdev,
 845                             "failed to transmit USB message to device: %d\n",
 846                              urb->status);
 847
 848                 /* update counters an cleanup */
 849                 spin_lock_irqsave(&up->echo_skb_lock, flags);
 850                 can_free_echo_skb(up->netdev, context - up->context_array);
 851                 spin_unlock_irqrestore(&up->echo_skb_lock, flags);
 852
 853                 up->netdev->stats.tx_dropped++;
 854
 855                 /* release context and restart the queue if necessary */
 856                 if (!ucan_release_context(up, context))
 857                         netdev_err(up->netdev,
 858                                    "urb failed, failed to release context\n");
 859         }
 860 }
 861
 862 static void ucan_cleanup_rx_urbs(struct ucan_priv *up, struct urb **urbs)
 863 {
 864         int i;
 865
 866         for (i = 0; i < UCAN_MAX_RX_URBS; i++) {
 867                 if (urbs[i]) {
 868                         usb_unanchor_urb(urbs[i]);
 869                         usb_free_coherent(up->udev,
 870                                           up->in_ep_size,
 871                                           urbs[i]->transfer_buffer,
 872                                           urbs[i]->transfer_dma);
 873                         usb_free_urb(urbs[i]);
 874                 }
 875         }
 876
 877         memset(urbs, 0, sizeof(*urbs) * UCAN_MAX_RX_URBS);
 878 }
 879
 880 static int ucan_prepare_and_anchor_rx_urbs(struct ucan_priv *up,
 881                                            struct urb **urbs)
 882 {
 883         int i;
 884
 885         memset(urbs, 0, sizeof(*urbs) * UCAN_MAX_RX_URBS);
 886
 887         for (i = 0; i < UCAN_MAX_RX_URBS; i++) {
 888                 void *buf;
 889
 890                 urbs[i] = usb_alloc_urb(0, GFP_KERNEL);
 891                 if (!urbs[i])
 892                         goto err;
 893
 894                 buf = usb_alloc_coherent(up->udev,
 895                                          up->in_ep_size,
 896                                          GFP_KERNEL, &urbs[i]->transfer_dma);
 897                 if (!buf) {
 898                         /* cleanup this urb */
 899                         usb_free_urb(urbs[i]);
 900                         urbs[i] = NULL;
 901                         goto err;
 902                 }
 903
 904                 usb_fill_bulk_urb(urbs[i], up->udev,
 905                                   usb_rcvbulkpipe(up->udev,
 906                                                   up->in_ep_addr),
 907                                   buf,
 908                                   up->in_ep_size,
 909                                   ucan_read_bulk_callback,
 910                                   up);
 911
 912                 urbs[i]->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 913
 914                 usb_anchor_urb(urbs[i], &up->rx_urbs);
 915         }
 916         return 0;
 917
 918 err:
 919         /* cleanup other unsubmitted urbs */
 920         ucan_cleanup_rx_urbs(up, urbs);
 921         return -ENOMEM;
 922 }
 923
 924 /* Submits rx urbs with the semantic: Either submit all, or cleanup
 925  * everything. I case of errors submitted urbs are killed and all urbs in
 926  * the array are freed. I case of no errors every entry in the urb
 927  * array is set to NULL.
 928  */
 929 static int ucan_submit_rx_urbs(struct ucan_priv *up, struct urb **urbs)
 930 {
 931         int i, ret;
 932
 933         /* Iterate over all urbs to submit. On success remove the urb
 934          * from the list.
 935          */
 936         for (i = 0; i < UCAN_MAX_RX_URBS; i++) {
 937                 ret = usb_submit_urb(urbs[i], GFP_KERNEL);
 938                 if (ret) {
 939                         netdev_err(up->netdev,
 940                                    "could not submit urb; code: %d\n",
 941                                    ret);
 942                         goto err;
 943                 }
 944
 945                 /* Anchor URB and drop reference, USB core will take
 946                  * care of freeing it
 947                  */
 948                 usb_free_urb(urbs[i]);
 949                 urbs[i] = NULL;
 950         }
 951         return 0;
 952
 953 err:
 954         /* Cleanup unsubmitted urbs */
 955         ucan_cleanup_rx_urbs(up, urbs);
 956
 957         /* Kill urbs that are already submitted */
 958         usb_kill_anchored_urbs(&up->rx_urbs);
 959
 960         return ret;
 961 }
 962
 963 /* Open the network device */
 964 static int ucan_open(struct net_device *netdev)
 965 {
 966         int ret, ret_cleanup;
 967         u16 ctrlmode;
 968         struct urb *urbs[UCAN_MAX_RX_URBS];
 969         struct ucan_priv *up = netdev_priv(netdev);
 970
 971         ret = ucan_alloc_context_array(up);
 972         if (ret)
 973                 return ret;
 974
 975         /* Allocate and prepare IN URBS - allocated and anchored
 976          * urbs are stored in urbs[] for clean
 977          */
 978         ret = ucan_prepare_and_anchor_rx_urbs(up, urbs);
 979         if (ret)
 980                 goto err_contexts;
 981
 982         /* Check the control mode */
 983         ctrlmode = 0;
 984         if (up->can.ctrlmode & CAN_CTRLMODE_LOOPBACK)
 985                 ctrlmode |= UCAN_MODE_LOOPBACK;
 986         if (up->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
 987                 ctrlmode |= UCAN_MODE_SILENT;
 988         if (up->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES)
 989                 ctrlmode |= UCAN_MODE_3_SAMPLES;
 990         if (up->can.ctrlmode & CAN_CTRLMODE_ONE_SHOT)
 991                 ctrlmode |= UCAN_MODE_ONE_SHOT;
 992
 993         /* Enable this in any case - filtering is down within the
 994          * receive path
 995          */
 996         ctrlmode |= UCAN_MODE_BERR_REPORT;
 997         up->ctl_msg_buffer->cmd_start.mode = cpu_to_le16(ctrlmode);
 998
 999         /* Driver is ready to receive data - start the USB device */
1000         ret = ucan_ctrl_command_out(up, UCAN_COMMAND_START, 0, 2);
1001         if (ret < 0) {
1002                 netdev_err(up->netdev,
1003                            "could not start device, code: %d\n",
1004                            ret);
1005                 goto err_reset;
1006         }
1007
1008         /* Call CAN layer open */
1009         ret = open_candev(netdev);
1010         if (ret)
1011                 goto err_stop;
1012
1013         /* Driver is ready to receive data. Submit RX URBS */
1014         ret = ucan_submit_rx_urbs(up, urbs);
1015         if (ret)
1016                 goto err_stop;
1017
1018         up->can.state = CAN_STATE_ERROR_ACTIVE;
1019
1020         /* Start the network queue */
1021         netif_start_queue(netdev);
1022
1023         return 0;
1024
1025 err_stop:
1026         /* The device have started already stop it */
1027         ret_cleanup = ucan_ctrl_command_out(up, UCAN_COMMAND_STOP, 0, 0);
1028         if (ret_cleanup < 0)
1029                 netdev_err(up->netdev,
1030                            "could not stop device, code: %d\n",
1031                            ret_cleanup);
1032
1033 err_reset:
1034         /* The device might have received data, reset it for
1035          * consistent state
1036          */
1037         ret_cleanup = ucan_ctrl_command_out(up, UCAN_COMMAND_RESET, 0, 0);
1038         if (ret_cleanup < 0)
1039                 netdev_err(up->netdev,
1040                            "could not reset device, code: %d\n",
1041                            ret_cleanup);
1042
1043         /* clean up unsubmitted urbs */
1044         ucan_cleanup_rx_urbs(up, urbs);
1045
1046 err_contexts:
1047         ucan_release_context_array(up);
1048         return ret;
1049 }
1050
1051 static struct urb *ucan_prepare_tx_urb(struct ucan_priv *up,
1052                                        struct ucan_urb_context *context,
1053                                        struct can_frame *cf,
1054                                        u8 echo_index)
1055 {
1056         int mlen;
1057         struct urb *urb;
1058         struct ucan_message_out *m;
1059
1060         /* create a URB, and a buffer for it, and copy the data to the URB */
1061         urb = usb_alloc_urb(0, GFP_ATOMIC);
1062         if (!urb) {
1063                 netdev_err(up->netdev, "no memory left for URBs\n");
1064                 return NULL;
1065         }
1066
1067         m = usb_alloc_coherent(up->udev,
1068                                sizeof(struct ucan_message_out),
1069                                GFP_ATOMIC,
1070                                &urb->transfer_dma);
1071         if (!m) {
1072                 netdev_err(up->netdev, "no memory left for USB buffer\n");
1073                 usb_free_urb(urb);
1074                 return NULL;
1075         }
1076
1077         /* build the USB message */
1078         m->type = UCAN_OUT_TX;
1079         m->msg.can_msg.id = cpu_to_le32(cf->can_id);
1080
1081         if (cf->can_id & CAN_RTR_FLAG) {
1082                 mlen = UCAN_OUT_HDR_SIZE +
1083                         offsetof(struct ucan_can_msg, dlc) +
1084                         sizeof(m->msg.can_msg.dlc);
1085                 m->msg.can_msg.dlc = cf->can_dlc;
1086         } else {
1087                 mlen = UCAN_OUT_HDR_SIZE +
1088                         sizeof(m->msg.can_msg.id) + cf->can_dlc;
1089                 memcpy(m->msg.can_msg.data, cf->data, cf->can_dlc);
1090         }
1091         m->len = cpu_to_le16(mlen);
1092
1093         context->dlc = cf->can_dlc;
1094
1095         m->subtype = echo_index;
1096
1097         /* build the urb */
1098         usb_fill_bulk_urb(urb, up->udev,
1099                           usb_sndbulkpipe(up->udev,
1100                                           up->out_ep_addr),
1101                           m, mlen, ucan_write_bulk_callback, context);
1102         urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
1103
1104         return urb;
1105 }
1106
1107 static void ucan_clean_up_tx_urb(struct ucan_priv *up, struct urb *urb)
1108 {
1109         usb_free_coherent(up->udev, sizeof(struct ucan_message_out),
1110                           urb->transfer_buffer, urb->transfer_dma);
1111         usb_free_urb(urb);
1112 }
1113
1114 /* callback when Linux needs to send a can frame */
1115 static netdev_tx_t ucan_start_xmit(struct sk_buff *skb,
1116                                    struct net_device *netdev)
1117 {
1118         unsigned long flags;
1119         int ret;
1120         u8 echo_index;
1121         struct urb *urb;
1122         struct ucan_urb_context *context;
1123         struct ucan_priv *up = netdev_priv(netdev);
1124         struct can_frame *cf = (struct can_frame *)skb->data;
1125
1126         /* check skb */
1127         if (can_dropped_invalid_skb(netdev, skb))
1128                 return NETDEV_TX_OK;
1129
1130         /* allocate a context and slow down tx path, if fifo state is low */
1131         context = ucan_alloc_context(up);
1132         echo_index = context - up->context_array;
1133
1134         if (WARN_ON_ONCE(!context))
1135                 return NETDEV_TX_BUSY;
1136
1137         /* prepare urb for transmission */
1138         urb = ucan_prepare_tx_urb(up, context, cf, echo_index);
1139         if (!urb)
1140                 goto drop;
1141
1142         /* put the skb on can loopback stack */
1143         spin_lock_irqsave(&up->echo_skb_lock, flags);
1144         can_put_echo_skb(skb, up->netdev, echo_index);
1145         spin_unlock_irqrestore(&up->echo_skb_lock, flags);
1146
1147         /* transmit it */
1148         usb_anchor_urb(urb, &up->tx_urbs);
1149         ret = usb_submit_urb(urb, GFP_ATOMIC);
1150
1151         /* cleanup urb */
1152         if (ret) {
1153                 /* on error, clean up */
1154                 usb_unanchor_urb(urb);
1155                 ucan_clean_up_tx_urb(up, urb);
1156                 if (!ucan_release_context(up, context))
1157                         netdev_err(up->netdev,
1158                                    "xmit err: failed to release context\n");
1159
1160                 /* remove the skb from the echo stack - this also
1161                  * frees the skb
1162                  */
1163                 spin_lock_irqsave(&up->echo_skb_lock, flags);
1164                 can_free_echo_skb(up->netdev, echo_index);
1165                 spin_unlock_irqrestore(&up->echo_skb_lock, flags);
1166
1167                 if (ret == -ENODEV) {
1168                         netif_device_detach(up->netdev);
1169                 } else {
1170                         netdev_warn(up->netdev,
1171                                     "xmit err: failed to submit urb %d\n",
1172                                     ret);
1173                         up->netdev->stats.tx_dropped++;
1174                 }
1175                 return NETDEV_TX_OK;
1176         }
1177
1178         netif_trans_update(netdev);
1179
1180         /* release ref, as we do not need the urb anymore */
1181         usb_free_urb(urb);
1182
1183         return NETDEV_TX_OK;
1184
1185 drop:
1186         if (!ucan_release_context(up, context))
1187                 netdev_err(up->netdev,
1188                            "xmit drop: failed to release context\n");
1189         dev_kfree_skb(skb);
1190         up->netdev->stats.tx_dropped++;
1191
1192         return NETDEV_TX_OK;
1193 }
1194
1195 /* Device goes down
1196  *
1197  * Clean up used resources
1198  */
1199 static int ucan_close(struct net_device *netdev)
1200 {
1201         int ret;
1202         struct ucan_priv *up = netdev_priv(netdev);
1203
1204         up->can.state = CAN_STATE_STOPPED;
1205
1206         /* stop sending data */
1207         usb_kill_anchored_urbs(&up->tx_urbs);
1208
1209         /* stop receiving data */
1210         usb_kill_anchored_urbs(&up->rx_urbs);
1211
1212         /* stop and reset can device */
1213         ret = ucan_ctrl_command_out(up, UCAN_COMMAND_STOP, 0, 0);
1214         if (ret < 0)
1215                 netdev_err(up->netdev,
1216                            "could not stop device, code: %d\n",
1217                            ret);
1218
1219         ret = ucan_ctrl_command_out(up, UCAN_COMMAND_RESET, 0, 0);
1220         if (ret < 0)
1221                 netdev_err(up->netdev,
1222                            "could not reset device, code: %d\n",
1223                            ret);
1224
1225         netif_stop_queue(netdev);
1226
1227         ucan_release_context_array(up);
1228
1229         close_candev(up->netdev);
1230         return 0;
1231 }
1232
1233 /* CAN driver callbacks */
1234 static const struct net_device_ops ucan_netdev_ops = {
1235         .ndo_open = ucan_open,
1236         .ndo_stop = ucan_close,
1237         .ndo_start_xmit = ucan_start_xmit,
1238         .ndo_change_mtu = can_change_mtu,
1239 };
1240
1241 /* Request to set bittiming
1242  *
1243  * This function generates an USB set bittiming message and transmits
1244  * it to the device
1245  */
1246 static int ucan_set_bittiming(struct net_device *netdev)
1247 {
1248         int ret;
1249         struct ucan_priv *up = netdev_priv(netdev);
1250         struct ucan_ctl_cmd_set_bittiming *cmd_set_bittiming;
1251
1252         cmd_set_bittiming = &up->ctl_msg_buffer->cmd_set_bittiming;
1253         cmd_set_bittiming->tq = cpu_to_le32(up->can.bittiming.tq);
1254         cmd_set_bittiming->brp = cpu_to_le16(up->can.bittiming.brp);
1255         cmd_set_bittiming->sample_point =
1256             cpu_to_le16(up->can.bittiming.sample_point);
1257         cmd_set_bittiming->prop_seg = up->can.bittiming.prop_seg;
1258         cmd_set_bittiming->phase_seg1 = up->can.bittiming.phase_seg1;
1259         cmd_set_bittiming->phase_seg2 = up->can.bittiming.phase_seg2;
1260         cmd_set_bittiming->sjw = up->can.bittiming.sjw;
1261
1262         ret = ucan_ctrl_command_out(up, UCAN_COMMAND_SET_BITTIMING, 0,
1263                                     sizeof(*cmd_set_bittiming));
1264         return (ret < 0) ? ret : 0;
1265 }
1266
1267 /* Restart the device to get it out of BUS-OFF state.
1268  * Called when the user runs "ip link set can1 type can restart".
1269  */
1270 static int ucan_set_mode(struct net_device *netdev, enum can_mode mode)
1271 {
1272         int ret;
1273         unsigned long flags;
1274         struct ucan_priv *up = netdev_priv(netdev);
1275
1276         switch (mode) {
1277         case CAN_MODE_START:
1278                 netdev_dbg(up->netdev, "restarting device\n");
1279
1280                 ret = ucan_ctrl_command_out(up, UCAN_COMMAND_RESTART, 0, 0);
1281                 up->can.state = CAN_STATE_ERROR_ACTIVE;
1282
1283                 /* check if queue can be restarted,
1284                  * up->available_tx_urbs must be protected by the
1285                  * lock
1286                  */
1287                 spin_lock_irqsave(&up->context_lock, flags);
1288
1289                 if (up->available_tx_urbs > 0)
1290                         netif_wake_queue(up->netdev);
1291
1292                 spin_unlock_irqrestore(&up->context_lock, flags);
1293
1294                 return ret;
1295         default:
1296                 return -EOPNOTSUPP;
1297         }
1298 }
1299
1300 /* Probe the device, reset it and gather general device information */
1301 static int ucan_probe(struct usb_interface *intf,
1302                       const struct usb_device_id *id)
1303 {
1304         int ret;
1305         int i;
1306         u32 protocol_version;
1307         struct usb_device *udev;
1308         struct net_device *netdev;
1309         struct usb_host_interface *iface_desc;
1310         struct ucan_priv *up;
1311         struct usb_endpoint_descriptor *ep;
1312         u16 in_ep_size;
1313         u16 out_ep_size;
1314         u8 in_ep_addr;
1315         u8 out_ep_addr;
1316         union ucan_ctl_payload *ctl_msg_buffer;
1317         char firmware_str[sizeof(union ucan_ctl_payload) + 1];
1318
1319         udev = interface_to_usbdev(intf);
1320
1321         /* Stage 1 - Interface Parsing
1322          * ---------------------------
1323          *
1324          * Identifie the device USB interface descriptor and its
1325          * endpoints. Probing is aborted on errors.
1326          */
1327
1328         /* check if the interface is sane */
1329         iface_desc = intf->cur_altsetting;
1330         if (!iface_desc)
1331                 return -ENODEV;
1332
1333         dev_info(&udev->dev,
1334                  "%s: probing device on interface #%d\n",
1335                  UCAN_DRIVER_NAME,
1336                  iface_desc->desc.bInterfaceNumber);
1337
1338         /* interface sanity check */
1339         if (iface_desc->desc.bNumEndpoints != 2) {
1340                 dev_err(&udev->dev,
1341                         "%s: invalid EP count (%d)",
1342                         UCAN_DRIVER_NAME, iface_desc->desc.bNumEndpoints);
1343                 goto err_firmware_needs_update;
1344         }
1345
1346         /* check interface endpoints */
1347         in_ep_addr = 0;
1348         out_ep_addr = 0;
1349         in_ep_size = 0;
1350         out_ep_size = 0;
1351         for (i = 0; i < iface_desc->desc.bNumEndpoints; i++) {
1352                 ep = &iface_desc->endpoint[i].desc;
1353
1354                 if (((ep->bEndpointAddress & USB_ENDPOINT_DIR_MASK) != 0) &&
1355                     ((ep->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) ==
1356                      USB_ENDPOINT_XFER_BULK)) {
1357                         /* In Endpoint */
1358                         in_ep_addr = ep->bEndpointAddress;
1359                         in_ep_addr &= USB_ENDPOINT_NUMBER_MASK;
1360                         in_ep_size = le16_to_cpu(ep->wMaxPacketSize);
1361                 } else if (((ep->bEndpointAddress & USB_ENDPOINT_DIR_MASK) ==
1362                             0) &&
1363                            ((ep->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) ==
1364                             USB_ENDPOINT_XFER_BULK)) {
1365                         /* Out Endpoint */
1366                         out_ep_addr = ep->bEndpointAddress;
1367                         out_ep_addr &= USB_ENDPOINT_NUMBER_MASK;
1368                         out_ep_size = le16_to_cpu(ep->wMaxPacketSize);
1369                 }
1370         }
1371
1372         /* check if interface is sane */
1373         if (!in_ep_addr || !out_ep_addr) {
1374                 dev_err(&udev->dev, "%s: invalid endpoint configuration\n",
1375                         UCAN_DRIVER_NAME);
1376                 goto err_firmware_needs_update;
1377         }
1378         if (in_ep_size < sizeof(struct ucan_message_in)) {
1379                 dev_err(&udev->dev, "%s: invalid in_ep MaxPacketSize\n",
1380                         UCAN_DRIVER_NAME);
1381                 goto err_firmware_needs_update;
1382         }
1383         if (out_ep_size < sizeof(struct ucan_message_out)) {
1384                 dev_err(&udev->dev, "%s: invalid out_ep MaxPacketSize\n",
1385                         UCAN_DRIVER_NAME);
1386                 goto err_firmware_needs_update;
1387         }
1388
1389         /* Stage 2 - Device Identification
1390          * -------------------------------
1391          *
1392          * The device interface seems to be a ucan device. Do further
1393          * compatibility checks. On error probing is aborted, on
1394          * success this stage leaves the ctl_msg_buffer with the
1395          * reported contents of a GET_INFO command (supported
1396          * bittimings, tx_fifo depth). This information is used in
1397          * Stage 3 for the final driver initialisation.
1398          */
1399
1400         /* Prepare Memory for control transferes */
1401         ctl_msg_buffer = devm_kzalloc(&udev->dev,
1402                                       sizeof(union ucan_ctl_payload),
1403                                       GFP_KERNEL);
1404         if (!ctl_msg_buffer) {
1405                 dev_err(&udev->dev,
1406                         "%s: failed to allocate control pipe memory\n",
1407                         UCAN_DRIVER_NAME);
1408                 return -ENOMEM;
1409         }
1410
1411         /* get protocol version
1412          *
1413          * note: ucan_ctrl_command_* wrappers cannot be used yet
1414          * because `up` is initialised in Stage 3
1415          */
1416         ret = usb_control_msg(udev,
1417                               usb_rcvctrlpipe(udev, 0),
1418                               UCAN_COMMAND_GET,
1419                               USB_DIR_IN | USB_TYPE_VENDOR |
1420                                         USB_RECIP_INTERFACE,
1421                               UCAN_COMMAND_GET_PROTOCOL_VERSION,
1422                               iface_desc->desc.bInterfaceNumber,
1423                               ctl_msg_buffer,
1424                               sizeof(union ucan_ctl_payload),
1425                               UCAN_USB_CTL_PIPE_TIMEOUT);
1426
1427         /* older firmware version do not support this command - those
1428          * are not supported by this drive
1429          */
1430         if (ret != 4) {
1431                 dev_err(&udev->dev,
1432                         "%s: could not read protocol version, ret=%d\n",
1433                         UCAN_DRIVER_NAME, ret);
1434                 if (ret >= 0)
1435                         ret = -EINVAL;
1436                 goto err_firmware_needs_update;
1437         }
1438
1439         /* this driver currently supports protocol version 3 only */
1440         protocol_version =
1441                 le32_to_cpu(ctl_msg_buffer->cmd_get_protocol_version.version);
1442         if (protocol_version < UCAN_PROTOCOL_VERSION_MIN ||
1443             protocol_version > UCAN_PROTOCOL_VERSION_MAX) {
1444                 dev_err(&udev->dev,
1445                         "%s: device protocol version %d is not supported\n",
1446                         UCAN_DRIVER_NAME, protocol_version);
1447                 goto err_firmware_needs_update;
1448         }
1449
1450         /* request the device information and store it in ctl_msg_buffer
1451          *
1452          * note: ucan_ctrl_command_* wrappers connot be used yet
1453          * because `up` is initialised in Stage 3
1454          */
1455         ret = usb_control_msg(udev,
1456                               usb_rcvctrlpipe(udev, 0),
1457                               UCAN_COMMAND_GET,
1458                               USB_DIR_IN | USB_TYPE_VENDOR |
1459                                         USB_RECIP_INTERFACE,
1460                               UCAN_COMMAND_GET_INFO,
1461                               iface_desc->desc.bInterfaceNumber,
1462                               ctl_msg_buffer,
1463                               sizeof(ctl_msg_buffer->cmd_get_device_info),
1464                               UCAN_USB_CTL_PIPE_TIMEOUT);
1465
1466         if (ret < 0) {
1467                 dev_err(&udev->dev, "%s: failed to retrieve device info\n",
1468                         UCAN_DRIVER_NAME);
1469                 goto err_firmware_needs_update;
1470         }
1471         if (ret < sizeof(ctl_msg_buffer->cmd_get_device_info)) {
1472                 dev_err(&udev->dev, "%s: device reported invalid device info\n",
1473                         UCAN_DRIVER_NAME);
1474                 goto err_firmware_needs_update;
1475         }
1476         if (ctl_msg_buffer->cmd_get_device_info.tx_fifo == 0) {
1477                 dev_err(&udev->dev,
1478                         "%s: device reported invalid tx-fifo size\n",
1479                         UCAN_DRIVER_NAME);
1480                 goto err_firmware_needs_update;
1481         }
1482
1483         /* Stage 3 - Driver Initialisation
1484          * -------------------------------
1485          *
1486          * Register device to Linux, prepare private structures and
1487          * reset the device.
1488          */
1489
1490         /* allocate driver resources */
1491         netdev = alloc_candev(sizeof(struct ucan_priv),
1492                               ctl_msg_buffer->cmd_get_device_info.tx_fifo);
1493         if (!netdev) {
1494                 dev_err(&udev->dev,
1495                         "%s: cannot allocate candev\n", UCAN_DRIVER_NAME);
1496                 return -ENOMEM;
1497         }
1498
1499         up = netdev_priv(netdev);
1500
1501         /* initialze data */
1502         up->udev = udev;
1503         up->intf = intf;
1504         up->netdev = netdev;
1505         up->intf_index = iface_desc->desc.bInterfaceNumber;
1506         up->in_ep_addr = in_ep_addr;
1507         up->out_ep_addr = out_ep_addr;
1508         up->in_ep_size = in_ep_size;
1509         up->ctl_msg_buffer = ctl_msg_buffer;
1510         up->context_array = NULL;
1511         up->available_tx_urbs = 0;
1512
1513         up->can.state = CAN_STATE_STOPPED;
1514         up->can.bittiming_const = &up->device_info.bittiming_const;
1515         up->can.do_set_bittiming = ucan_set_bittiming;
1516         up->can.do_set_mode = &ucan_set_mode;
1517         spin_lock_init(&up->context_lock);
1518         spin_lock_init(&up->echo_skb_lock);
1519         netdev->netdev_ops = &ucan_netdev_ops;
1520
1521         usb_set_intfdata(intf, up);
1522         SET_NETDEV_DEV(netdev, &intf->dev);
1523
1524         /* parse device information
1525          * the data retrieved in Stage 2 is still available in
1526          * up->ctl_msg_buffer
1527          */
1528         ucan_parse_device_info(up, &ctl_msg_buffer->cmd_get_device_info);
1529
1530         /* just print some device information - if available */
1531         ret = ucan_device_request_in(up, UCAN_DEVICE_GET_FW_STRING, 0,
1532                                      sizeof(union ucan_ctl_payload));
1533         if (ret > 0) {
1534                 /* copy string while ensuring zero terminiation */
1535                 strncpy(firmware_str, up->ctl_msg_buffer->raw,
1536                         sizeof(union ucan_ctl_payload));
1537                 firmware_str[sizeof(union ucan_ctl_payload)] = '\0';
1538         } else {
1539                 strcpy(firmware_str, "unknown");
1540         }
1541
1542         /* device is compatible, reset it */
1543         ret = ucan_ctrl_command_out(up, UCAN_COMMAND_RESET, 0, 0);
1544         if (ret < 0)
1545                 goto err_free_candev;
1546
1547         init_usb_anchor(&up->rx_urbs);
1548         init_usb_anchor(&up->tx_urbs);
1549
1550         up->can.state = CAN_STATE_STOPPED;
1551
1552         /* register the device */
1553         ret = register_candev(netdev);
1554         if (ret)
1555                 goto err_free_candev;
1556
1557         /* initialisation complete, log device info */
1558         netdev_info(up->netdev, "registered device\n");
1559         netdev_info(up->netdev, "firmware string: %s\n", firmware_str);
1560
1561         /* success */
1562         return 0;
1563
1564 err_free_candev:
1565         free_candev(netdev);
1566         return ret;
1567
1568 err_firmware_needs_update:
1569         dev_err(&udev->dev,
1570                 "%s: probe failed; try to update the device firmware\n",
1571                 UCAN_DRIVER_NAME);
1572         return -ENODEV;
1573 }
1574
1575 /* disconnect the device */
1576 static void ucan_disconnect(struct usb_interface *intf)
1577 {
1578         struct ucan_priv *up = usb_get_intfdata(intf);
1579
1580         usb_set_intfdata(intf, NULL);
1581
1582         if (up) {
1583                 unregister_netdev(up->netdev);
1584                 free_candev(up->netdev);
1585         }
1586 }
1587
1588 static struct usb_device_id ucan_table[] = {
1589         /* Mule (soldered onto compute modules) */
1590         {USB_DEVICE_INTERFACE_NUMBER(0x2294, 0x425a, 0)},
1591         /* Seal (standalone USB stick) */
1592         {USB_DEVICE_INTERFACE_NUMBER(0x2294, 0x425b, 0)},
1593         {} /* Terminating entry */
1594 };
1595
1596 MODULE_DEVICE_TABLE(usb, ucan_table);
1597 /* driver callbacks */
1598 static struct usb_driver ucan_driver = {
1599         .name = UCAN_DRIVER_NAME,
1600         .probe = ucan_probe,
1601         .disconnect = ucan_disconnect,
1602         .id_table = ucan_table,
1603 };
1604
1605 module_usb_driver(ucan_driver);
1606
1607 MODULE_LICENSE("GPL v2");
1608 MODULE_AUTHOR("Martin Elshuber <martin.elshuber@theobroma-systems.com>");
1609 MODULE_AUTHOR("Jakob Unterwurzacher <jakob.unterwurzacher@theobroma-systems.com>");
1610 MODULE_DESCRIPTION("Driver for Theobroma Systems UCAN devices");