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/ethtool.h>
  32 #include <linux/module.h>
  33 #include <linux/netdevice.h>
  34 #include <linux/signal.h>
  35 #include <linux/skbuff.h>
  36 #include <linux/slab.h>
  37 #include <linux/usb.h>
  38
  39 #define UCAN_DRIVER_NAME "ucan"
  40 #define UCAN_MAX_RX_URBS 8
  41 /* the CAN controller needs a while to enable/disable the bus */
  42 #define UCAN_USB_CTL_PIPE_TIMEOUT 1000
  43 /* this driver currently supports protocol version 3 only */
  44 #define UCAN_PROTOCOL_VERSION_MIN 3
  45 #define UCAN_PROTOCOL_VERSION_MAX 3
  46
  47 /* UCAN Message Definitions
  48  * ------------------------
  49  *
  50  *  ucan_message_out_t and ucan_message_in_t define the messages
  51  *  transmitted on the OUT and IN endpoint.
  52  *
  53  *  Multibyte fields are transmitted with little endianness
  54  *
  55  *  INTR Endpoint: a single uint32_t storing the current space in the fifo
  56  *
  57  *  OUT Endpoint: single message of type ucan_message_out_t is
  58  *    transmitted on the out endpoint
  59  *
  60  *  IN Endpoint: multiple messages ucan_message_in_t concateted in
  61  *    the following way:
  62  *
  63  *      m[n].len <=> the length if message n(including the header in bytes)
  64  *      m[n] is is aligned to a 4 byte boundary, hence
  65  *        offset(m[0])   := 0;
  66  *        offset(m[n+1]) := offset(m[n]) + (m[n].len + 3) & 3
  67  *
  68  *      this implies that
  69  *        offset(m[n]) % 4 <=> 0
  70  */
  71
  72 /* Device Global Commands */
  73 enum {
  74         UCAN_DEVICE_GET_FW_STRING = 0,
  75 };
  76
  77 /* UCAN Commands */
  78 enum {
  79         /* start the can transceiver - val defines the operation mode */
  80         UCAN_COMMAND_START = 0,
  81         /* cancel pending transmissions and stop the can transceiver */
  82         UCAN_COMMAND_STOP = 1,
  83         /* send can transceiver into low-power sleep mode */
  84         UCAN_COMMAND_SLEEP = 2,
  85         /* wake up can transceiver from low-power sleep mode */
  86         UCAN_COMMAND_WAKEUP = 3,
  87         /* reset the can transceiver */
  88         UCAN_COMMAND_RESET = 4,
  89         /* get piece of info from the can transceiver - subcmd defines what
  90          * piece
  91          */
  92         UCAN_COMMAND_GET = 5,
  93         /* clear or disable hardware filter - subcmd defines which of the two */
  94         UCAN_COMMAND_FILTER = 6,
  95         /* Setup bittiming */
  96         UCAN_COMMAND_SET_BITTIMING = 7,
  97         /* recover from bus-off state */
  98         UCAN_COMMAND_RESTART = 8,
  99 };
 100
 101 /* UCAN_COMMAND_START and UCAN_COMMAND_GET_INFO operation modes (bitmap).
 102  * Undefined bits must be set to 0.
 103  */
 104 enum {
 105         UCAN_MODE_LOOPBACK = BIT(0),
 106         UCAN_MODE_SILENT = BIT(1),
 107         UCAN_MODE_3_SAMPLES = BIT(2),
 108         UCAN_MODE_ONE_SHOT = BIT(3),
 109         UCAN_MODE_BERR_REPORT = BIT(4),
 110 };
 111
 112 /* UCAN_COMMAND_GET subcommands */
 113 enum {
 114         UCAN_COMMAND_GET_INFO = 0,
 115         UCAN_COMMAND_GET_PROTOCOL_VERSION = 1,
 116 };
 117
 118 /* UCAN_COMMAND_FILTER subcommands */
 119 enum {
 120         UCAN_FILTER_CLEAR = 0,
 121         UCAN_FILTER_DISABLE = 1,
 122         UCAN_FILTER_ENABLE = 2,
 123 };
 124
 125 /* OUT endpoint message types */
 126 enum {
 127         UCAN_OUT_TX = 2,     /* transmit a CAN frame */
 128 };
 129
 130 /* IN endpoint message types */
 131 enum {
 132         UCAN_IN_TX_COMPLETE = 1,  /* CAN frame transmission completed */
 133         UCAN_IN_RX = 2,           /* CAN frame received */
 134 };
 135
 136 struct ucan_ctl_cmd_start {
 137         __le16 mode;         /* OR-ing any of UCAN_MODE_* */
 138 } __packed;
 139
 140 struct ucan_ctl_cmd_set_bittiming {
 141         __le32 tq;           /* Time quanta (TQ) in nanoseconds */
 142         __le16 brp;          /* TQ Prescaler */
 143         __le16 sample_point; /* Samplepoint on tenth percent */
 144         u8 prop_seg;         /* Propagation segment in TQs */
 145         u8 phase_seg1;       /* Phase buffer segment 1 in TQs */
 146         u8 phase_seg2;       /* Phase buffer segment 2 in TQs */
 147         u8 sjw;              /* Synchronisation jump width in TQs */
 148 } __packed;
 149
 150 struct ucan_ctl_cmd_device_info {
 151         __le32 freq;         /* Clock Frequency for tq generation */
 152         u8 tx_fifo;          /* Size of the transmission fifo */
 153         u8 sjw_max;          /* can_bittiming fields... */
 154         u8 tseg1_min;
 155         u8 tseg1_max;
 156         u8 tseg2_min;
 157         u8 tseg2_max;
 158         __le16 brp_inc;
 159         __le32 brp_min;
 160         __le32 brp_max;      /* ...can_bittiming fields */
 161         __le16 ctrlmodes;    /* supported control modes */
 162         __le16 hwfilter;     /* Number of HW filter banks */
 163         __le16 rxmboxes;     /* Number of receive Mailboxes */
 164 } __packed;
 165
 166 struct ucan_ctl_cmd_get_protocol_version {
 167         __le32 version;
 168 } __packed;
 169
 170 union ucan_ctl_payload {
 171         /* Setup Bittiming
 172          * bmRequest == UCAN_COMMAND_START
 173          */
 174         struct ucan_ctl_cmd_start cmd_start;
 175         /* Setup Bittiming
 176          * bmRequest == UCAN_COMMAND_SET_BITTIMING
 177          */
 178         struct ucan_ctl_cmd_set_bittiming cmd_set_bittiming;
 179         /* Get Device Information
 180          * bmRequest == UCAN_COMMAND_GET; wValue = UCAN_COMMAND_GET_INFO
 181          */
 182         struct ucan_ctl_cmd_device_info cmd_get_device_info;
 183         /* Get Protocol Version
 184          * bmRequest == UCAN_COMMAND_GET;
 185          * wValue = UCAN_COMMAND_GET_PROTOCOL_VERSION
 186          */
 187         struct ucan_ctl_cmd_get_protocol_version cmd_get_protocol_version;
 188
 189         u8 raw[128];
 190 } __packed;
 191
 192 enum {
 193         UCAN_TX_COMPLETE_SUCCESS = BIT(0),
 194 };
 195
 196 /* Transmission Complete within ucan_message_in */
 197 struct ucan_tx_complete_entry_t {
 198         u8 echo_index;
 199         u8 flags;
 200 } __packed __aligned(0x2);
 201
 202 /* CAN Data message format within ucan_message_in/out */
 203 struct ucan_can_msg {
 204         /* note DLC is computed by
 205          *    msg.len - sizeof (msg.len)
 206          *            - sizeof (msg.type)
 207          *            - sizeof (msg.can_msg.id)
 208          */
 209         __le32 id;
 210
 211         union {
 212                 u8 data[CAN_MAX_DLEN];  /* Data of CAN frames */
 213                 u8 dlc;                 /* RTR dlc */
 214         };
 215 } __packed;
 216
 217 /* OUT Endpoint, outbound messages */
 218 struct ucan_message_out {
 219         __le16 len; /* Length of the content include header */
 220         u8 type;    /* UCAN_OUT_TX and friends */
 221         u8 subtype; /* command sub type */
 222
 223         union {
 224                 /* Transmit CAN frame
 225                  * (type == UCAN_TX) && ((msg.can_msg.id & CAN_RTR_FLAG) == 0)
 226                  * subtype stores the echo id
 227                  */
 228                 struct ucan_can_msg can_msg;
 229         } msg;
 230 } __packed __aligned(0x4);
 231
 232 /* IN Endpoint, inbound messages */
 233 struct ucan_message_in {
 234         __le16 len; /* Length of the content include header */
 235         u8 type;    /* UCAN_IN_RX and friends */
 236         u8 subtype; /* command sub type */
 237
 238         union {
 239                 /* CAN Frame received
 240                  * (type == UCAN_IN_RX)
 241                  * && ((msg.can_msg.id & CAN_RTR_FLAG) == 0)
 242                  */
 243                 struct ucan_can_msg can_msg;
 244
 245                 /* CAN transmission complete
 246                  * (type == UCAN_IN_TX_COMPLETE)
 247                  */
 248                 DECLARE_FLEX_ARRAY(struct ucan_tx_complete_entry_t,
 249                                    can_tx_complete_msg);
 250         } __aligned(0x4) msg;
 251 } __packed __aligned(0x4);
 252
 253 /* Macros to calculate message lengths */
 254 #define UCAN_OUT_HDR_SIZE offsetof(struct ucan_message_out, msg)
 255
 256 #define UCAN_IN_HDR_SIZE offsetof(struct ucan_message_in, msg)
 257 #define UCAN_IN_LEN(member) (UCAN_OUT_HDR_SIZE + sizeof(member))
 258
 259 struct ucan_priv;
 260
 261 /* Context Information for transmission URBs */
 262 struct ucan_urb_context {
 263         struct ucan_priv *up;
 264         bool allocated;
 265 };
 266
 267 /* Information reported by the USB device */
 268 struct ucan_device_info {
 269         struct can_bittiming_const bittiming_const;
 270         u8 tx_fifo;
 271 };
 272
 273 /* Driver private data */
 274 struct ucan_priv {
 275         /* must be the first member */
 276         struct can_priv can;
 277
 278         /* linux USB device structures */
 279         struct usb_device *udev;
 280         struct net_device *netdev;
 281
 282         /* lock for can->echo_skb (used around
 283          * can_put/get/free_echo_skb
 284          */
 285         spinlock_t echo_skb_lock;
 286
 287         /* usb device information */
 288         u8 intf_index;
 289         u8 in_ep_addr;
 290         u8 out_ep_addr;
 291         u16 in_ep_size;
 292
 293         /* transmission and reception buffers */
 294         struct usb_anchor rx_urbs;
 295         struct usb_anchor tx_urbs;
 296
 297         union ucan_ctl_payload *ctl_msg_buffer;
 298         struct ucan_device_info device_info;
 299
 300         /* transmission control information and locks */
 301         spinlock_t context_lock;
 302         unsigned int available_tx_urbs;
 303         struct ucan_urb_context *context_array;
 304 };
 305
 306 static u8 ucan_can_cc_dlc2len(struct ucan_can_msg *msg, u16 len)
 307 {
 308         if (le32_to_cpu(msg->id) & CAN_RTR_FLAG)
 309                 return can_cc_dlc2len(msg->dlc);
 310         else
 311                 return can_cc_dlc2len(len - (UCAN_IN_HDR_SIZE + sizeof(msg->id)));
 312 }
 313
 314 static void ucan_release_context_array(struct ucan_priv *up)
 315 {
 316         if (!up->context_array)
 317                 return;
 318
 319         /* lock is not needed because, driver is currently opening or closing */
 320         up->available_tx_urbs = 0;
 321
 322         kfree(up->context_array);
 323         up->context_array = NULL;
 324 }
 325
 326 static int ucan_alloc_context_array(struct ucan_priv *up)
 327 {
 328         int i;
 329
 330         /* release contexts if any */
 331         ucan_release_context_array(up);
 332
 333         up->context_array = kcalloc(up->device_info.tx_fifo,
 334                                     sizeof(*up->context_array),
 335                                     GFP_KERNEL);
 336         if (!up->context_array) {
 337                 netdev_err(up->netdev,
 338                            "Not enough memory to allocate tx contexts\n");
 339                 return -ENOMEM;
 340         }
 341
 342         for (i = 0; i < up->device_info.tx_fifo; i++) {
 343                 up->context_array[i].allocated = false;
 344                 up->context_array[i].up = up;
 345         }
 346
 347         /* lock is not needed because, driver is currently opening */
 348         up->available_tx_urbs = up->device_info.tx_fifo;
 349
 350         return 0;
 351 }
 352
 353 static struct ucan_urb_context *ucan_alloc_context(struct ucan_priv *up)
 354 {
 355         int i;
 356         unsigned long flags;
 357         struct ucan_urb_context *ret = NULL;
 358
 359         if (WARN_ON_ONCE(!up->context_array))
 360                 return NULL;
 361
 362         /* execute context operation atomically */
 363         spin_lock_irqsave(&up->context_lock, flags);
 364
 365         for (i = 0; i < up->device_info.tx_fifo; i++) {
 366                 if (!up->context_array[i].allocated) {
 367                         /* update context */
 368                         ret = &up->context_array[i];
 369                         up->context_array[i].allocated = true;
 370
 371                         /* stop queue if necessary */
 372                         up->available_tx_urbs--;
 373                         if (!up->available_tx_urbs)
 374                                 netif_stop_queue(up->netdev);
 375
 376                         break;
 377                 }
 378         }
 379
 380         spin_unlock_irqrestore(&up->context_lock, flags);
 381         return ret;
 382 }
 383
 384 static bool ucan_release_context(struct ucan_priv *up,
 385                                  struct ucan_urb_context *ctx)
 386 {
 387         unsigned long flags;
 388         bool ret = false;
 389
 390         if (WARN_ON_ONCE(!up->context_array))
 391                 return false;
 392
 393         /* execute context operation atomically */
 394         spin_lock_irqsave(&up->context_lock, flags);
 395
 396         /* context was not allocated, maybe the device sent garbage */
 397         if (ctx->allocated) {
 398                 ctx->allocated = false;
 399
 400                 /* check if the queue needs to be woken */
 401                 if (!up->available_tx_urbs)
 402                         netif_wake_queue(up->netdev);
 403                 up->available_tx_urbs++;
 404
 405                 ret = true;
 406         }
 407
 408         spin_unlock_irqrestore(&up->context_lock, flags);
 409         return ret;
 410 }
 411
 412 static int ucan_ctrl_command_out(struct ucan_priv *up,
 413                                  u8 cmd, u16 subcmd, u16 datalen)
 414 {
 415         return usb_control_msg(up->udev,
 416                                usb_sndctrlpipe(up->udev, 0),
 417                                cmd,
 418                                USB_DIR_OUT | USB_TYPE_VENDOR |
 419                                                 USB_RECIP_INTERFACE,
 420                                subcmd,
 421                                up->intf_index,
 422                                up->ctl_msg_buffer,
 423                                datalen,
 424                                UCAN_USB_CTL_PIPE_TIMEOUT);
 425 }
 426
 427 static int ucan_device_request_in(struct ucan_priv *up,
 428                                   u8 cmd, u16 subcmd, u16 datalen)
 429 {
 430         return usb_control_msg(up->udev,
 431                                usb_rcvctrlpipe(up->udev, 0),
 432                                cmd,
 433                                USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
 434                                subcmd,
 435                                0,
 436                                up->ctl_msg_buffer,
 437                                datalen,
 438                                UCAN_USB_CTL_PIPE_TIMEOUT);
 439 }
 440
 441 /* Parse the device information structure reported by the device and
 442  * setup private variables accordingly
 443  */
 444 static void ucan_parse_device_info(struct ucan_priv *up,
 445                                    struct ucan_ctl_cmd_device_info *device_info)
 446 {
 447         struct can_bittiming_const *bittiming =
 448                 &up->device_info.bittiming_const;
 449         u16 ctrlmodes;
 450
 451         /* store the data */
 452         up->can.clock.freq = le32_to_cpu(device_info->freq);
 453         up->device_info.tx_fifo = device_info->tx_fifo;
 454         strcpy(bittiming->name, "ucan");
 455         bittiming->tseg1_min = device_info->tseg1_min;
 456         bittiming->tseg1_max = device_info->tseg1_max;
 457         bittiming->tseg2_min = device_info->tseg2_min;
 458         bittiming->tseg2_max = device_info->tseg2_max;
 459         bittiming->sjw_max = device_info->sjw_max;
 460         bittiming->brp_min = le32_to_cpu(device_info->brp_min);
 461         bittiming->brp_max = le32_to_cpu(device_info->brp_max);
 462         bittiming->brp_inc = le16_to_cpu(device_info->brp_inc);
 463
 464         ctrlmodes = le16_to_cpu(device_info->ctrlmodes);
 465
 466         up->can.ctrlmode_supported = 0;
 467
 468         if (ctrlmodes & UCAN_MODE_LOOPBACK)
 469                 up->can.ctrlmode_supported |= CAN_CTRLMODE_LOOPBACK;
 470         if (ctrlmodes & UCAN_MODE_SILENT)
 471                 up->can.ctrlmode_supported |= CAN_CTRLMODE_LISTENONLY;
 472         if (ctrlmodes & UCAN_MODE_3_SAMPLES)
 473                 up->can.ctrlmode_supported |= CAN_CTRLMODE_3_SAMPLES;
 474         if (ctrlmodes & UCAN_MODE_ONE_SHOT)
 475                 up->can.ctrlmode_supported |= CAN_CTRLMODE_ONE_SHOT;
 476         if (ctrlmodes & UCAN_MODE_BERR_REPORT)
 477                 up->can.ctrlmode_supported |= CAN_CTRLMODE_BERR_REPORTING;
 478 }
 479
 480 /* Handle a CAN error frame that we have received from the device.
 481  * Returns true if the can state has changed.
 482  */
 483 static bool ucan_handle_error_frame(struct ucan_priv *up,
 484                                     struct ucan_message_in *m,
 485                                     canid_t canid)
 486 {
 487         enum can_state new_state = up->can.state;
 488         struct net_device_stats *net_stats = &up->netdev->stats;
 489         struct can_device_stats *can_stats = &up->can.can_stats;
 490
 491         if (canid & CAN_ERR_LOSTARB)
 492                 can_stats->arbitration_lost++;
 493
 494         if (canid & CAN_ERR_BUSERROR)
 495                 can_stats->bus_error++;
 496
 497         if (canid & CAN_ERR_ACK)
 498                 net_stats->tx_errors++;
 499
 500         if (canid & CAN_ERR_BUSOFF)
 501                 new_state = CAN_STATE_BUS_OFF;
 502
 503         /* controller problems, details in data[1] */
 504         if (canid & CAN_ERR_CRTL) {
 505                 u8 d1 = m->msg.can_msg.data[1];
 506
 507                 if (d1 & CAN_ERR_CRTL_RX_OVERFLOW)
 508                         net_stats->rx_over_errors++;
 509
 510                 /* controller state bits: if multiple are set the worst wins */
 511                 if (d1 & CAN_ERR_CRTL_ACTIVE)
 512                         new_state = CAN_STATE_ERROR_ACTIVE;
 513
 514                 if (d1 & (CAN_ERR_CRTL_RX_WARNING | CAN_ERR_CRTL_TX_WARNING))
 515                         new_state = CAN_STATE_ERROR_WARNING;
 516
 517                 if (d1 & (CAN_ERR_CRTL_RX_PASSIVE | CAN_ERR_CRTL_TX_PASSIVE))
 518                         new_state = CAN_STATE_ERROR_PASSIVE;
 519         }
 520
 521         /* protocol error, details in data[2] */
 522         if (canid & CAN_ERR_PROT) {
 523                 u8 d2 = m->msg.can_msg.data[2];
 524
 525                 if (d2 & CAN_ERR_PROT_TX)
 526                         net_stats->tx_errors++;
 527                 else
 528                         net_stats->rx_errors++;
 529         }
 530
 531         /* no state change - we are done */
 532         if (up->can.state == new_state)
 533                 return false;
 534
 535         /* we switched into a better state */
 536         if (up->can.state > new_state) {
 537                 up->can.state = new_state;
 538                 return true;
 539         }
 540
 541         /* we switched into a worse state */
 542         up->can.state = new_state;
 543         switch (new_state) {
 544         case CAN_STATE_BUS_OFF:
 545                 can_stats->bus_off++;
 546                 can_bus_off(up->netdev);
 547                 break;
 548         case CAN_STATE_ERROR_PASSIVE:
 549                 can_stats->error_passive++;
 550                 break;
 551         case CAN_STATE_ERROR_WARNING:
 552                 can_stats->error_warning++;
 553                 break;
 554         default:
 555                 break;
 556         }
 557         return true;
 558 }
 559
 560 /* Callback on reception of a can frame via the IN endpoint
 561  *
 562  * This function allocates an skb and transferres it to the Linux
 563  * network stack
 564  */
 565 static void ucan_rx_can_msg(struct ucan_priv *up, struct ucan_message_in *m)
 566 {
 567         int len;
 568         canid_t canid;
 569         struct can_frame *cf;
 570         struct sk_buff *skb;
 571         struct net_device_stats *stats = &up->netdev->stats;
 572
 573         /* get the contents of the length field */
 574         len = le16_to_cpu(m->len);
 575
 576         /* check sanity */
 577         if (len < UCAN_IN_HDR_SIZE + sizeof(m->msg.can_msg.id)) {
 578                 netdev_warn(up->netdev, "invalid input message len: %d\n", len);
 579                 return;
 580         }
 581
 582         /* handle error frames */
 583         canid = le32_to_cpu(m->msg.can_msg.id);
 584         if (canid & CAN_ERR_FLAG) {
 585                 bool busstate_changed = ucan_handle_error_frame(up, m, canid);
 586
 587                 /* if berr-reporting is off only state changes get through */
 588                 if (!(up->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING) &&
 589                     !busstate_changed)
 590                         return;
 591         } else {
 592                 canid_t canid_mask;
 593                 /* compute the mask for canid */
 594                 canid_mask = CAN_RTR_FLAG;
 595                 if (canid & CAN_EFF_FLAG)
 596                         canid_mask |= CAN_EFF_MASK | CAN_EFF_FLAG;
 597                 else
 598                         canid_mask |= CAN_SFF_MASK;
 599
 600                 if (canid & ~canid_mask)
 601                         netdev_warn(up->netdev,
 602                                     "unexpected bits set (canid %x, mask %x)",
 603                                     canid, canid_mask);
 604
 605                 canid &= canid_mask;
 606         }
 607
 608         /* allocate skb */
 609         skb = alloc_can_skb(up->netdev, &cf);
 610         if (!skb)
 611                 return;
 612
 613         /* fill the can frame */
 614         cf->can_id = canid;
 615
 616         /* compute DLC taking RTR_FLAG into account */
 617         cf->len = ucan_can_cc_dlc2len(&m->msg.can_msg, len);
 618
 619         /* copy the payload of non RTR frames */
 620         if (!(cf->can_id & CAN_RTR_FLAG) || (cf->can_id & CAN_ERR_FLAG))
 621                 memcpy(cf->data, m->msg.can_msg.data, cf->len);
 622
 623         /* don't count error frames as real packets */
 624         if (!(cf->can_id & CAN_ERR_FLAG)) {
 625                 stats->rx_packets++;
 626                 if (!(cf->can_id & CAN_RTR_FLAG))
 627                         stats->rx_bytes += cf->len;
 628         }
 629
 630         /* pass it to Linux */
 631         netif_rx(skb);
 632 }
 633
 634 /* callback indicating completed transmission */
 635 static void ucan_tx_complete_msg(struct ucan_priv *up,
 636                                  struct ucan_message_in *m)
 637 {
 638         unsigned long flags;
 639         u16 count, i;
 640         u8 echo_index;
 641         u16 len = le16_to_cpu(m->len);
 642
 643         struct ucan_urb_context *context;
 644
 645         if (len < UCAN_IN_HDR_SIZE || (len % 2 != 0)) {
 646                 netdev_err(up->netdev, "invalid tx complete length\n");
 647                 return;
 648         }
 649
 650         count = (len - UCAN_IN_HDR_SIZE) / 2;
 651         for (i = 0; i < count; i++) {
 652                 /* we did not submit such echo ids */
 653                 echo_index = m->msg.can_tx_complete_msg[i].echo_index;
 654                 if (echo_index >= up->device_info.tx_fifo) {
 655                         up->netdev->stats.tx_errors++;
 656                         netdev_err(up->netdev,
 657                                    "invalid echo_index %d received\n",
 658                                    echo_index);
 659                         continue;
 660                 }
 661
 662                 /* gather information from the context */
 663                 context = &up->context_array[echo_index];
 664
 665                 /* Release context and restart queue if necessary.
 666                  * Also check if the context was allocated
 667                  */
 668                 if (!ucan_release_context(up, context))
 669                         continue;
 670
 671                 spin_lock_irqsave(&up->echo_skb_lock, flags);
 672                 if (m->msg.can_tx_complete_msg[i].flags &
 673                     UCAN_TX_COMPLETE_SUCCESS) {
 674                         /* update statistics */
 675                         up->netdev->stats.tx_packets++;
 676                         up->netdev->stats.tx_bytes +=
 677                                 can_get_echo_skb(up->netdev, echo_index, NULL);
 678                 } else {
 679                         up->netdev->stats.tx_dropped++;
 680                         can_free_echo_skb(up->netdev, echo_index, NULL);
 681                 }
 682                 spin_unlock_irqrestore(&up->echo_skb_lock, flags);
 683         }
 684 }
 685
 686 /* callback on reception of a USB message */
 687 static void ucan_read_bulk_callback(struct urb *urb)
 688 {
 689         int ret;
 690         int pos;
 691         struct ucan_priv *up = urb->context;
 692         struct net_device *netdev = up->netdev;
 693         struct ucan_message_in *m;
 694
 695         /* the device is not up and the driver should not receive any
 696          * data on the bulk in pipe
 697          */
 698         if (WARN_ON(!up->context_array)) {
 699                 usb_free_coherent(up->udev,
 700                                   up->in_ep_size,
 701                                   urb->transfer_buffer,
 702                                   urb->transfer_dma);
 703                 return;
 704         }
 705
 706         /* check URB status */
 707         switch (urb->status) {
 708         case 0:
 709                 break;
 710         case -ENOENT:
 711         case -EPIPE:
 712         case -EPROTO:
 713         case -ESHUTDOWN:
 714         case -ETIME:
 715                 /* urb is not resubmitted -> free dma data */
 716                 usb_free_coherent(up->udev,
 717                                   up->in_ep_size,
 718                                   urb->transfer_buffer,
 719                                   urb->transfer_dma);
 720                 netdev_dbg(up->netdev, "not resubmitting urb; status: %d\n",
 721                            urb->status);
 722                 return;
 723         default:
 724                 goto resubmit;
 725         }
 726
 727         /* sanity check */
 728         if (!netif_device_present(netdev))
 729                 return;
 730
 731         /* iterate over input */
 732         pos = 0;
 733         while (pos < urb->actual_length) {
 734                 int len;
 735
 736                 /* check sanity (length of header) */
 737                 if ((urb->actual_length - pos) < UCAN_IN_HDR_SIZE) {
 738                         netdev_warn(up->netdev,
 739                                     "invalid message (short; no hdr; l:%d)\n",
 740                                     urb->actual_length);
 741                         goto resubmit;
 742                 }
 743
 744                 /* setup the message address */
 745                 m = (struct ucan_message_in *)
 746                         ((u8 *)urb->transfer_buffer + pos);
 747                 len = le16_to_cpu(m->len);
 748
 749                 /* check sanity (length of content) */
 750                 if (urb->actual_length - pos < len) {
 751                         netdev_warn(up->netdev,
 752                                     "invalid message (short; no data; l:%d)\n",
 753                                     urb->actual_length);
 754                         print_hex_dump(KERN_WARNING,
 755                                        "raw data: ",
 756                                        DUMP_PREFIX_ADDRESS,
 757                                        16,
 758                                        1,
 759                                        urb->transfer_buffer,
 760                                        urb->actual_length,
 761                                        true);
 762
 763                         goto resubmit;
 764                 }
 765
 766                 switch (m->type) {
 767                 case UCAN_IN_RX:
 768                         ucan_rx_can_msg(up, m);
 769                         break;
 770                 case UCAN_IN_TX_COMPLETE:
 771                         ucan_tx_complete_msg(up, m);
 772                         break;
 773                 default:
 774                         netdev_warn(up->netdev,
 775                                     "invalid message (type; t:%d)\n",
 776                                     m->type);
 777                         break;
 778                 }
 779
 780                 /* proceed to next message */
 781                 pos += len;
 782                 /* align to 4 byte boundary */
 783                 pos = round_up(pos, 4);
 784         }
 785
 786 resubmit:
 787         /* resubmit urb when done */
 788         usb_fill_bulk_urb(urb, up->udev,
 789                           usb_rcvbulkpipe(up->udev,
 790                                           up->in_ep_addr),
 791                           urb->transfer_buffer,
 792                           up->in_ep_size,
 793                           ucan_read_bulk_callback,
 794                           up);
 795
 796         usb_anchor_urb(urb, &up->rx_urbs);
 797         ret = usb_submit_urb(urb, GFP_ATOMIC);
 798
 799         if (ret < 0) {
 800                 netdev_err(up->netdev,
 801                            "failed resubmitting read bulk urb: %d\n",
 802                            ret);
 803
 804                 usb_unanchor_urb(urb);
 805                 usb_free_coherent(up->udev,
 806                                   up->in_ep_size,
 807                                   urb->transfer_buffer,
 808                                   urb->transfer_dma);
 809
 810                 if (ret == -ENODEV)
 811                         netif_device_detach(netdev);
 812         }
 813 }
 814
 815 /* callback after transmission of a USB message */
 816 static void ucan_write_bulk_callback(struct urb *urb)
 817 {
 818         unsigned long flags;
 819         struct ucan_priv *up;
 820         struct ucan_urb_context *context = urb->context;
 821
 822         /* get the urb context */
 823         if (WARN_ON_ONCE(!context))
 824                 return;
 825
 826         /* free up our allocated buffer */
 827         usb_free_coherent(urb->dev,
 828                           sizeof(struct ucan_message_out),
 829                           urb->transfer_buffer,
 830                           urb->transfer_dma);
 831
 832         up = context->up;
 833         if (WARN_ON_ONCE(!up))
 834                 return;
 835
 836         /* sanity check */
 837         if (!netif_device_present(up->netdev))
 838                 return;
 839
 840         /* transmission failed (USB - the device will not send a TX complete) */
 841         if (urb->status) {
 842                 netdev_warn(up->netdev,
 843                             "failed to transmit USB message to device: %d\n",
 844                              urb->status);
 845
 846                 /* update counters an cleanup */
 847                 spin_lock_irqsave(&up->echo_skb_lock, flags);
 848                 can_free_echo_skb(up->netdev, context - up->context_array, NULL);
 849                 spin_unlock_irqrestore(&up->echo_skb_lock, flags);
 850
 851                 up->netdev->stats.tx_dropped++;
 852
 853                 /* release context and restart the queue if necessary */
 854                 if (!ucan_release_context(up, context))
 855                         netdev_err(up->netdev,
 856                                    "urb failed, failed to release context\n");
 857         }
 858 }
 859
 860 static void ucan_cleanup_rx_urbs(struct ucan_priv *up, struct urb **urbs)
 861 {
 862         int i;
 863
 864         for (i = 0; i < UCAN_MAX_RX_URBS; i++) {
 865                 if (urbs[i]) {
 866                         usb_unanchor_urb(urbs[i]);
 867                         usb_free_coherent(up->udev,
 868                                           up->in_ep_size,
 869                                           urbs[i]->transfer_buffer,
 870                                           urbs[i]->transfer_dma);
 871                         usb_free_urb(urbs[i]);
 872                 }
 873         }
 874
 875         memset(urbs, 0, sizeof(*urbs) * UCAN_MAX_RX_URBS);
 876 }
 877
 878 static int ucan_prepare_and_anchor_rx_urbs(struct ucan_priv *up,
 879                                            struct urb **urbs)
 880 {
 881         int i;
 882
 883         memset(urbs, 0, sizeof(*urbs) * UCAN_MAX_RX_URBS);
 884
 885         for (i = 0; i < UCAN_MAX_RX_URBS; i++) {
 886                 void *buf;
 887
 888                 urbs[i] = usb_alloc_urb(0, GFP_KERNEL);
 889                 if (!urbs[i])
 890                         goto err;
 891
 892                 buf = usb_alloc_coherent(up->udev,
 893                                          up->in_ep_size,
 894                                          GFP_KERNEL, &urbs[i]->transfer_dma);
 895                 if (!buf) {
 896                         /* cleanup this urb */
 897                         usb_free_urb(urbs[i]);
 898                         urbs[i] = NULL;
 899                         goto err;
 900                 }
 901
 902                 usb_fill_bulk_urb(urbs[i], up->udev,
 903                                   usb_rcvbulkpipe(up->udev,
 904                                                   up->in_ep_addr),
 905                                   buf,
 906                                   up->in_ep_size,
 907                                   ucan_read_bulk_callback,
 908                                   up);
 909
 910                 urbs[i]->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 911
 912                 usb_anchor_urb(urbs[i], &up->rx_urbs);
 913         }
 914         return 0;
 915
 916 err:
 917         /* cleanup other unsubmitted urbs */
 918         ucan_cleanup_rx_urbs(up, urbs);
 919         return -ENOMEM;
 920 }
 921
 922 /* Submits rx urbs with the semantic: Either submit all, or cleanup
 923  * everything. I case of errors submitted urbs are killed and all urbs in
 924  * the array are freed. I case of no errors every entry in the urb
 925  * array is set to NULL.
 926  */
 927 static int ucan_submit_rx_urbs(struct ucan_priv *up, struct urb **urbs)
 928 {
 929         int i, ret;
 930
 931         /* Iterate over all urbs to submit. On success remove the urb
 932          * from the list.
 933          */
 934         for (i = 0; i < UCAN_MAX_RX_URBS; i++) {
 935                 ret = usb_submit_urb(urbs[i], GFP_KERNEL);
 936                 if (ret) {
 937                         netdev_err(up->netdev,
 938                                    "could not submit urb; code: %d\n",
 939                                    ret);
 940                         goto err;
 941                 }
 942
 943                 /* Anchor URB and drop reference, USB core will take
 944                  * care of freeing it
 945                  */
 946                 usb_free_urb(urbs[i]);
 947                 urbs[i] = NULL;
 948         }
 949         return 0;
 950
 951 err:
 952         /* Cleanup unsubmitted urbs */
 953         ucan_cleanup_rx_urbs(up, urbs);
 954
 955         /* Kill urbs that are already submitted */
 956         usb_kill_anchored_urbs(&up->rx_urbs);
 957
 958         return ret;
 959 }
 960
 961 /* Open the network device */
 962 static int ucan_open(struct net_device *netdev)
 963 {
 964         int ret, ret_cleanup;
 965         u16 ctrlmode;
 966         struct urb *urbs[UCAN_MAX_RX_URBS];
 967         struct ucan_priv *up = netdev_priv(netdev);
 968
 969         ret = ucan_alloc_context_array(up);
 970         if (ret)
 971                 return ret;
 972
 973         /* Allocate and prepare IN URBS - allocated and anchored
 974          * urbs are stored in urbs[] for clean
 975          */
 976         ret = ucan_prepare_and_anchor_rx_urbs(up, urbs);
 977         if (ret)
 978                 goto err_contexts;
 979
 980         /* Check the control mode */
 981         ctrlmode = 0;
 982         if (up->can.ctrlmode & CAN_CTRLMODE_LOOPBACK)
 983                 ctrlmode |= UCAN_MODE_LOOPBACK;
 984         if (up->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
 985                 ctrlmode |= UCAN_MODE_SILENT;
 986         if (up->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES)
 987                 ctrlmode |= UCAN_MODE_3_SAMPLES;
 988         if (up->can.ctrlmode & CAN_CTRLMODE_ONE_SHOT)
 989                 ctrlmode |= UCAN_MODE_ONE_SHOT;
 990
 991         /* Enable this in any case - filtering is down within the
 992          * receive path
 993          */
 994         ctrlmode |= UCAN_MODE_BERR_REPORT;
 995         up->ctl_msg_buffer->cmd_start.mode = cpu_to_le16(ctrlmode);
 996
 997         /* Driver is ready to receive data - start the USB device */
 998         ret = ucan_ctrl_command_out(up, UCAN_COMMAND_START, 0, 2);
 999         if (ret < 0) {
1000                 netdev_err(up->netdev,
1001                            "could not start device, code: %d\n",
1002                            ret);
1003                 goto err_reset;
1004         }
1005
1006         /* Call CAN layer open */
1007         ret = open_candev(netdev);
1008         if (ret)
1009                 goto err_stop;
1010
1011         /* Driver is ready to receive data. Submit RX URBS */
1012         ret = ucan_submit_rx_urbs(up, urbs);
1013         if (ret)
1014                 goto err_stop;
1015
1016         up->can.state = CAN_STATE_ERROR_ACTIVE;
1017
1018         /* Start the network queue */
1019         netif_start_queue(netdev);
1020
1021         return 0;
1022
1023 err_stop:
1024         /* The device have started already stop it */
1025         ret_cleanup = ucan_ctrl_command_out(up, UCAN_COMMAND_STOP, 0, 0);
1026         if (ret_cleanup < 0)
1027                 netdev_err(up->netdev,
1028                            "could not stop device, code: %d\n",
1029                            ret_cleanup);
1030
1031 err_reset:
1032         /* The device might have received data, reset it for
1033          * consistent state
1034          */
1035         ret_cleanup = ucan_ctrl_command_out(up, UCAN_COMMAND_RESET, 0, 0);
1036         if (ret_cleanup < 0)
1037                 netdev_err(up->netdev,
1038                            "could not reset device, code: %d\n",
1039                            ret_cleanup);
1040
1041         /* clean up unsubmitted urbs */
1042         ucan_cleanup_rx_urbs(up, urbs);
1043
1044 err_contexts:
1045         ucan_release_context_array(up);
1046         return ret;
1047 }
1048
1049 static struct urb *ucan_prepare_tx_urb(struct ucan_priv *up,
1050                                        struct ucan_urb_context *context,
1051                                        struct can_frame *cf,
1052                                        u8 echo_index)
1053 {
1054         int mlen;
1055         struct urb *urb;
1056         struct ucan_message_out *m;
1057
1058         /* create a URB, and a buffer for it, and copy the data to the URB */
1059         urb = usb_alloc_urb(0, GFP_ATOMIC);
1060         if (!urb) {
1061                 netdev_err(up->netdev, "no memory left for URBs\n");
1062                 return NULL;
1063         }
1064
1065         m = usb_alloc_coherent(up->udev,
1066                                sizeof(struct ucan_message_out),
1067                                GFP_ATOMIC,
1068                                &urb->transfer_dma);
1069         if (!m) {
1070                 netdev_err(up->netdev, "no memory left for USB buffer\n");
1071                 usb_free_urb(urb);
1072                 return NULL;
1073         }
1074
1075         /* build the USB message */
1076         m->type = UCAN_OUT_TX;
1077         m->msg.can_msg.id = cpu_to_le32(cf->can_id);
1078
1079         if (cf->can_id & CAN_RTR_FLAG) {
1080                 mlen = UCAN_OUT_HDR_SIZE +
1081                         offsetof(struct ucan_can_msg, dlc) +
1082                         sizeof(m->msg.can_msg.dlc);
1083                 m->msg.can_msg.dlc = cf->len;
1084         } else {
1085                 mlen = UCAN_OUT_HDR_SIZE +
1086                         sizeof(m->msg.can_msg.id) + cf->len;
1087                 memcpy(m->msg.can_msg.data, cf->data, cf->len);
1088         }
1089         m->len = cpu_to_le16(mlen);
1090
1091         m->subtype = echo_index;
1092
1093         /* build the urb */
1094         usb_fill_bulk_urb(urb, up->udev,
1095                           usb_sndbulkpipe(up->udev,
1096                                           up->out_ep_addr),
1097                           m, mlen, ucan_write_bulk_callback, context);
1098         urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
1099
1100         return urb;
1101 }
1102
1103 static void ucan_clean_up_tx_urb(struct ucan_priv *up, struct urb *urb)
1104 {
1105         usb_free_coherent(up->udev, sizeof(struct ucan_message_out),
1106                           urb->transfer_buffer, urb->transfer_dma);
1107         usb_free_urb(urb);
1108 }
1109
1110 /* callback when Linux needs to send a can frame */
1111 static netdev_tx_t ucan_start_xmit(struct sk_buff *skb,
1112                                    struct net_device *netdev)
1113 {
1114         unsigned long flags;
1115         int ret;
1116         u8 echo_index;
1117         struct urb *urb;
1118         struct ucan_urb_context *context;
1119         struct ucan_priv *up = netdev_priv(netdev);
1120         struct can_frame *cf = (struct can_frame *)skb->data;
1121
1122         /* check skb */
1123         if (can_dev_dropped_skb(netdev, skb))
1124                 return NETDEV_TX_OK;
1125
1126         /* allocate a context and slow down tx path, if fifo state is low */
1127         context = ucan_alloc_context(up);
1128         echo_index = context - up->context_array;
1129
1130         if (WARN_ON_ONCE(!context))
1131                 return NETDEV_TX_BUSY;
1132
1133         /* prepare urb for transmission */
1134         urb = ucan_prepare_tx_urb(up, context, cf, echo_index);
1135         if (!urb)
1136                 goto drop;
1137
1138         /* put the skb on can loopback stack */
1139         spin_lock_irqsave(&up->echo_skb_lock, flags);
1140         can_put_echo_skb(skb, up->netdev, echo_index, 0);
1141         spin_unlock_irqrestore(&up->echo_skb_lock, flags);
1142
1143         /* transmit it */
1144         usb_anchor_urb(urb, &up->tx_urbs);
1145         ret = usb_submit_urb(urb, GFP_ATOMIC);
1146
1147         /* cleanup urb */
1148         if (ret) {
1149                 /* on error, clean up */
1150                 usb_unanchor_urb(urb);
1151                 ucan_clean_up_tx_urb(up, urb);
1152                 if (!ucan_release_context(up, context))
1153                         netdev_err(up->netdev,
1154                                    "xmit err: failed to release context\n");
1155
1156                 /* remove the skb from the echo stack - this also
1157                  * frees the skb
1158                  */
1159                 spin_lock_irqsave(&up->echo_skb_lock, flags);
1160                 can_free_echo_skb(up->netdev, echo_index, NULL);
1161                 spin_unlock_irqrestore(&up->echo_skb_lock, flags);
1162
1163                 if (ret == -ENODEV) {
1164                         netif_device_detach(up->netdev);
1165                 } else {
1166                         netdev_warn(up->netdev,
1167                                     "xmit err: failed to submit urb %d\n",
1168                                     ret);
1169                         up->netdev->stats.tx_dropped++;
1170                 }
1171                 return NETDEV_TX_OK;
1172         }
1173
1174         netif_trans_update(netdev);
1175
1176         /* release ref, as we do not need the urb anymore */
1177         usb_free_urb(urb);
1178
1179         return NETDEV_TX_OK;
1180
1181 drop:
1182         if (!ucan_release_context(up, context))
1183                 netdev_err(up->netdev,
1184                            "xmit drop: failed to release context\n");
1185         dev_kfree_skb(skb);
1186         up->netdev->stats.tx_dropped++;
1187
1188         return NETDEV_TX_OK;
1189 }
1190
1191 /* Device goes down
1192  *
1193  * Clean up used resources
1194  */
1195 static int ucan_close(struct net_device *netdev)
1196 {
1197         int ret;
1198         struct ucan_priv *up = netdev_priv(netdev);
1199
1200         up->can.state = CAN_STATE_STOPPED;
1201
1202         /* stop sending data */
1203         usb_kill_anchored_urbs(&up->tx_urbs);
1204
1205         /* stop receiving data */
1206         usb_kill_anchored_urbs(&up->rx_urbs);
1207
1208         /* stop and reset can device */
1209         ret = ucan_ctrl_command_out(up, UCAN_COMMAND_STOP, 0, 0);
1210         if (ret < 0)
1211                 netdev_err(up->netdev,
1212                            "could not stop device, code: %d\n",
1213                            ret);
1214
1215         ret = ucan_ctrl_command_out(up, UCAN_COMMAND_RESET, 0, 0);
1216         if (ret < 0)
1217                 netdev_err(up->netdev,
1218                            "could not reset device, code: %d\n",
1219                            ret);
1220
1221         netif_stop_queue(netdev);
1222
1223         ucan_release_context_array(up);
1224
1225         close_candev(up->netdev);
1226         return 0;
1227 }
1228
1229 /* CAN driver callbacks */
1230 static const struct net_device_ops ucan_netdev_ops = {
1231         .ndo_open = ucan_open,
1232         .ndo_stop = ucan_close,
1233         .ndo_start_xmit = ucan_start_xmit,
1234         .ndo_change_mtu = can_change_mtu,
1235 };
1236
1237 static const struct ethtool_ops ucan_ethtool_ops = {
1238         .get_ts_info = ethtool_op_get_ts_info,
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 transfers */
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 cannot 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         /* initialize data */
1502         up->udev = udev;
1503         up->netdev = netdev;
1504         up->intf_index = iface_desc->desc.bInterfaceNumber;
1505         up->in_ep_addr = in_ep_addr;
1506         up->out_ep_addr = out_ep_addr;
1507         up->in_ep_size = in_ep_size;
1508         up->ctl_msg_buffer = ctl_msg_buffer;
1509         up->context_array = NULL;
1510         up->available_tx_urbs = 0;
1511
1512         up->can.state = CAN_STATE_STOPPED;
1513         up->can.bittiming_const = &up->device_info.bittiming_const;
1514         up->can.do_set_bittiming = ucan_set_bittiming;
1515         up->can.do_set_mode = &ucan_set_mode;
1516         spin_lock_init(&up->context_lock);
1517         spin_lock_init(&up->echo_skb_lock);
1518         netdev->netdev_ops = &ucan_netdev_ops;
1519         netdev->ethtool_ops = &ucan_ethtool_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 termination */
1535                 strscpy(firmware_str, up->ctl_msg_buffer->raw,
1536                         sizeof(union ucan_ctl_payload) + 1);
1537         } else {
1538                 strcpy(firmware_str, "unknown");
1539         }
1540
1541         /* device is compatible, reset it */
1542         ret = ucan_ctrl_command_out(up, UCAN_COMMAND_RESET, 0, 0);
1543         if (ret < 0)
1544                 goto err_free_candev;
1545
1546         init_usb_anchor(&up->rx_urbs);
1547         init_usb_anchor(&up->tx_urbs);
1548
1549         up->can.state = CAN_STATE_STOPPED;
1550
1551         /* register the device */
1552         ret = register_candev(netdev);
1553         if (ret)
1554                 goto err_free_candev;
1555
1556         /* initialisation complete, log device info */
1557         netdev_info(up->netdev, "registered device\n");
1558         netdev_info(up->netdev, "firmware string: %s\n", firmware_str);
1559
1560         /* success */
1561         return 0;
1562
1563 err_free_candev:
1564         free_candev(netdev);
1565         return ret;
1566
1567 err_firmware_needs_update:
1568         dev_err(&udev->dev,
1569                 "%s: probe failed; try to update the device firmware\n",
1570                 UCAN_DRIVER_NAME);
1571         return -ENODEV;
1572 }
1573
1574 /* disconnect the device */
1575 static void ucan_disconnect(struct usb_interface *intf)
1576 {
1577         struct ucan_priv *up = usb_get_intfdata(intf);
1578
1579         usb_set_intfdata(intf, NULL);
1580
1581         if (up) {
1582                 unregister_candev(up->netdev);
1583                 free_candev(up->netdev);
1584         }
1585 }
1586
1587 static struct usb_device_id ucan_table[] = {
1588         /* Mule (soldered onto compute modules) */
1589         {USB_DEVICE_INTERFACE_NUMBER(0x2294, 0x425a, 0)},
1590         /* Seal (standalone USB stick) */
1591         {USB_DEVICE_INTERFACE_NUMBER(0x2294, 0x425b, 0)},
1592         {} /* Terminating entry */
1593 };
1594
1595 MODULE_DEVICE_TABLE(usb, ucan_table);
1596 /* driver callbacks */
1597 static struct usb_driver ucan_driver = {
1598         .name = UCAN_DRIVER_NAME,
1599         .probe = ucan_probe,
1600         .disconnect = ucan_disconnect,
1601         .id_table = ucan_table,
1602 };
1603
1604 module_usb_driver(ucan_driver);
1605
1606 MODULE_LICENSE("GPL v2");
1607 MODULE_AUTHOR("Martin Elshuber <[email protected]>");
1608 MODULE_AUTHOR("Jakob Unterwurzacher <[email protected]>");
1609 MODULE_DESCRIPTION("Driver for Theobroma Systems UCAN devices");