drivers/net/can/bfin_can.c

   1 /*
   2  * Blackfin On-Chip CAN Driver
   3  *
   4  * Copyright 2004-2009 Analog Devices Inc.
   5  *
   6  * Enter bugs at http://blackfin.uclinux.org/
   7  *
   8  * Licensed under the GPL-2 or later.
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/kernel.h>
  13 #include <linux/bitops.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/errno.h>
  16 #include <linux/netdevice.h>
  17 #include <linux/skbuff.h>
  18 #include <linux/platform_device.h>
  19
  20 #include <linux/can/dev.h>
  21 #include <linux/can/error.h>
  22
  23 #include <asm/bfin_can.h>
  24 #include <asm/portmux.h>
  25
  26 #define DRV_NAME "bfin_can"
  27 #define BFIN_CAN_TIMEOUT 100
  28 #define TX_ECHO_SKB_MAX  1
  29
  30 /*
  31  * bfin can private data
  32  */
  33 struct bfin_can_priv {
  34         struct can_priv can;    /* must be the first member */
  35         struct net_device *dev;
  36         void __iomem *membase;
  37         int rx_irq;
  38         int tx_irq;
  39         int err_irq;
  40         unsigned short *pin_list;
  41 };
  42
  43 /*
  44  * bfin can timing parameters
  45  */
  46 static const struct can_bittiming_const bfin_can_bittiming_const = {
  47         .name = DRV_NAME,
  48         .tseg1_min = 1,
  49         .tseg1_max = 16,
  50         .tseg2_min = 1,
  51         .tseg2_max = 8,
  52         .sjw_max = 4,
  53         /*
  54          * Although the BRP field can be set to any value, it is recommended
  55          * that the value be greater than or equal to 4, as restrictions
  56          * apply to the bit timing configuration when BRP is less than 4.
  57          */
  58         .brp_min = 4,
  59         .brp_max = 1024,
  60         .brp_inc = 1,
  61 };
  62
  63 static int bfin_can_set_bittiming(struct net_device *dev)
  64 {
  65         struct bfin_can_priv *priv = netdev_priv(dev);
  66         struct bfin_can_regs __iomem *reg = priv->membase;
  67         struct can_bittiming *bt = &priv->can.bittiming;
  68         u16 clk, timing;
  69
  70         clk = bt->brp - 1;
  71         timing = ((bt->sjw - 1) << 8) | (bt->prop_seg + bt->phase_seg1 - 1) |
  72                 ((bt->phase_seg2 - 1) << 4);
  73
  74         /*
  75          * If the SAM bit is set, the input signal is oversampled three times
  76          * at the SCLK rate.
  77          */
  78         if (priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES)
  79                 timing |= SAM;
  80
  81         bfin_write(&reg->clock, clk);
  82         bfin_write(&reg->timing, timing);
  83
  84         netdev_info(dev, "setting CLOCK=0x%04x TIMING=0x%04x\n", clk, timing);
  85
  86         return 0;
  87 }
  88
  89 static void bfin_can_set_reset_mode(struct net_device *dev)
  90 {
  91         struct bfin_can_priv *priv = netdev_priv(dev);
  92         struct bfin_can_regs __iomem *reg = priv->membase;
  93         int timeout = BFIN_CAN_TIMEOUT;
  94         int i;
  95
  96         /* disable interrupts */
  97         bfin_write(&reg->mbim1, 0);
  98         bfin_write(&reg->mbim2, 0);
  99         bfin_write(&reg->gim, 0);
 100
 101         /* reset can and enter configuration mode */
 102         bfin_write(&reg->control, SRS | CCR);
 103         SSYNC();
 104         bfin_write(&reg->control, CCR);
 105         SSYNC();
 106         while (!(bfin_read(&reg->control) & CCA)) {
 107                 udelay(10);
 108                 if (--timeout == 0) {
 109                         netdev_err(dev, "fail to enter configuration mode\n");
 110                         BUG();
 111                 }
 112         }
 113
 114         /*
 115          * All mailbox configurations are marked as inactive
 116          * by writing to CAN Mailbox Configuration Registers 1 and 2
 117          * For all bits: 0 - Mailbox disabled, 1 - Mailbox enabled
 118          */
 119         bfin_write(&reg->mc1, 0);
 120         bfin_write(&reg->mc2, 0);
 121
 122         /* Set Mailbox Direction */
 123         bfin_write(&reg->md1, 0xFFFF);   /* mailbox 1-16 are RX */
 124         bfin_write(&reg->md2, 0);   /* mailbox 17-32 are TX */
 125
 126         /* RECEIVE_STD_CHL */
 127         for (i = 0; i < 2; i++) {
 128                 bfin_write(&reg->chl[RECEIVE_STD_CHL + i].id0, 0);
 129                 bfin_write(&reg->chl[RECEIVE_STD_CHL + i].id1, AME);
 130                 bfin_write(&reg->chl[RECEIVE_STD_CHL + i].dlc, 0);
 131                 bfin_write(&reg->msk[RECEIVE_STD_CHL + i].amh, 0x1FFF);
 132                 bfin_write(&reg->msk[RECEIVE_STD_CHL + i].aml, 0xFFFF);
 133         }
 134
 135         /* RECEIVE_EXT_CHL */
 136         for (i = 0; i < 2; i++) {
 137                 bfin_write(&reg->chl[RECEIVE_EXT_CHL + i].id0, 0);
 138                 bfin_write(&reg->chl[RECEIVE_EXT_CHL + i].id1, AME | IDE);
 139                 bfin_write(&reg->chl[RECEIVE_EXT_CHL + i].dlc, 0);
 140                 bfin_write(&reg->msk[RECEIVE_EXT_CHL + i].amh, 0x1FFF);
 141                 bfin_write(&reg->msk[RECEIVE_EXT_CHL + i].aml, 0xFFFF);
 142         }
 143
 144         bfin_write(&reg->mc2, BIT(TRANSMIT_CHL - 16));
 145         bfin_write(&reg->mc1, BIT(RECEIVE_STD_CHL) + BIT(RECEIVE_EXT_CHL));
 146         SSYNC();
 147
 148         priv->can.state = CAN_STATE_STOPPED;
 149 }
 150
 151 static void bfin_can_set_normal_mode(struct net_device *dev)
 152 {
 153         struct bfin_can_priv *priv = netdev_priv(dev);
 154         struct bfin_can_regs __iomem *reg = priv->membase;
 155         int timeout = BFIN_CAN_TIMEOUT;
 156
 157         /*
 158          * leave configuration mode
 159          */
 160         bfin_write(&reg->control, bfin_read(&reg->control) & ~CCR);
 161
 162         while (bfin_read(&reg->status) & CCA) {
 163                 udelay(10);
 164                 if (--timeout == 0) {
 165                         netdev_err(dev, "fail to leave configuration mode\n");
 166                         BUG();
 167                 }
 168         }
 169
 170         /*
 171          * clear _All_  tx and rx interrupts
 172          */
 173         bfin_write(&reg->mbtif1, 0xFFFF);
 174         bfin_write(&reg->mbtif2, 0xFFFF);
 175         bfin_write(&reg->mbrif1, 0xFFFF);
 176         bfin_write(&reg->mbrif2, 0xFFFF);
 177
 178         /*
 179          * clear global interrupt status register
 180          */
 181         bfin_write(&reg->gis, 0x7FF); /* overwrites with '1' */
 182
 183         /*
 184          * Initialize Interrupts
 185          * - set bits in the mailbox interrupt mask register
 186          * - global interrupt mask
 187          */
 188         bfin_write(&reg->mbim1, BIT(RECEIVE_STD_CHL) + BIT(RECEIVE_EXT_CHL));
 189         bfin_write(&reg->mbim2, BIT(TRANSMIT_CHL - 16));
 190
 191         bfin_write(&reg->gim, EPIM | BOIM | RMLIM);
 192         SSYNC();
 193 }
 194
 195 static void bfin_can_start(struct net_device *dev)
 196 {
 197         struct bfin_can_priv *priv = netdev_priv(dev);
 198
 199         /* enter reset mode */
 200         if (priv->can.state != CAN_STATE_STOPPED)
 201                 bfin_can_set_reset_mode(dev);
 202
 203         /* leave reset mode */
 204         bfin_can_set_normal_mode(dev);
 205 }
 206
 207 static int bfin_can_set_mode(struct net_device *dev, enum can_mode mode)
 208 {
 209         switch (mode) {
 210         case CAN_MODE_START:
 211                 bfin_can_start(dev);
 212                 if (netif_queue_stopped(dev))
 213                         netif_wake_queue(dev);
 214                 break;
 215
 216         default:
 217                 return -EOPNOTSUPP;
 218         }
 219
 220         return 0;
 221 }
 222
 223 static int bfin_can_get_berr_counter(const struct net_device *dev,
 224                                      struct can_berr_counter *bec)
 225 {
 226         struct bfin_can_priv *priv = netdev_priv(dev);
 227         struct bfin_can_regs __iomem *reg = priv->membase;
 228
 229         u16 cec = bfin_read(&reg->cec);
 230
 231         bec->txerr = cec >> 8;
 232         bec->rxerr = cec;
 233
 234         return 0;
 235 }
 236
 237 static int bfin_can_start_xmit(struct sk_buff *skb, struct net_device *dev)
 238 {
 239         struct bfin_can_priv *priv = netdev_priv(dev);
 240         struct bfin_can_regs __iomem *reg = priv->membase;
 241         struct can_frame *cf = (struct can_frame *)skb->data;
 242         u8 dlc = cf->can_dlc;
 243         canid_t id = cf->can_id;
 244         u8 *data = cf->data;
 245         u16 val;
 246         int i;
 247
 248         if (can_dropped_invalid_skb(dev, skb))
 249                 return NETDEV_TX_OK;
 250
 251         netif_stop_queue(dev);
 252
 253         /* fill id */
 254         if (id & CAN_EFF_FLAG) {
 255                 bfin_write(&reg->chl[TRANSMIT_CHL].id0, id);
 256                 val = ((id & 0x1FFF0000) >> 16) | IDE;
 257         } else
 258                 val = (id << 2);
 259         if (id & CAN_RTR_FLAG)
 260                 val |= RTR;
 261         bfin_write(&reg->chl[TRANSMIT_CHL].id1, val | AME);
 262
 263         /* fill payload */
 264         for (i = 0; i < 8; i += 2) {
 265                 val = ((7 - i) < dlc ? (data[7 - i]) : 0) +
 266                         ((6 - i) < dlc ? (data[6 - i] << 8) : 0);
 267                 bfin_write(&reg->chl[TRANSMIT_CHL].data[i], val);
 268         }
 269
 270         /* fill data length code */
 271         bfin_write(&reg->chl[TRANSMIT_CHL].dlc, dlc);
 272
 273         can_put_echo_skb(skb, dev, 0);
 274
 275         /* set transmit request */
 276         bfin_write(&reg->trs2, BIT(TRANSMIT_CHL - 16));
 277
 278         return 0;
 279 }
 280
 281 static void bfin_can_rx(struct net_device *dev, u16 isrc)
 282 {
 283         struct bfin_can_priv *priv = netdev_priv(dev);
 284         struct net_device_stats *stats = &dev->stats;
 285         struct bfin_can_regs __iomem *reg = priv->membase;
 286         struct can_frame *cf;
 287         struct sk_buff *skb;
 288         int obj;
 289         int i;
 290         u16 val;
 291
 292         skb = alloc_can_skb(dev, &cf);
 293         if (skb == NULL)
 294                 return;
 295
 296         /* get id */
 297         if (isrc & BIT(RECEIVE_EXT_CHL)) {
 298                 /* extended frame format (EFF) */
 299                 cf->can_id = ((bfin_read(&reg->chl[RECEIVE_EXT_CHL].id1)
 300                              & 0x1FFF) << 16)
 301                              + bfin_read(&reg->chl[RECEIVE_EXT_CHL].id0);
 302                 cf->can_id |= CAN_EFF_FLAG;
 303                 obj = RECEIVE_EXT_CHL;
 304         } else {
 305                 /* standard frame format (SFF) */
 306                 cf->can_id = (bfin_read(&reg->chl[RECEIVE_STD_CHL].id1)
 307                              & 0x1ffc) >> 2;
 308                 obj = RECEIVE_STD_CHL;
 309         }
 310         if (bfin_read(&reg->chl[obj].id1) & RTR)
 311                 cf->can_id |= CAN_RTR_FLAG;
 312
 313         /* get data length code */
 314         cf->can_dlc = get_can_dlc(bfin_read(&reg->chl[obj].dlc) & 0xF);
 315
 316         /* get payload */
 317         for (i = 0; i < 8; i += 2) {
 318                 val = bfin_read(&reg->chl[obj].data[i]);
 319                 cf->data[7 - i] = (7 - i) < cf->can_dlc ? val : 0;
 320                 cf->data[6 - i] = (6 - i) < cf->can_dlc ? (val >> 8) : 0;
 321         }
 322
 323         netif_rx(skb);
 324
 325         stats->rx_packets++;
 326         stats->rx_bytes += cf->can_dlc;
 327 }
 328
 329 static int bfin_can_err(struct net_device *dev, u16 isrc, u16 status)
 330 {
 331         struct bfin_can_priv *priv = netdev_priv(dev);
 332         struct bfin_can_regs __iomem *reg = priv->membase;
 333         struct net_device_stats *stats = &dev->stats;
 334         struct can_frame *cf;
 335         struct sk_buff *skb;
 336         enum can_state state = priv->can.state;
 337
 338         skb = alloc_can_err_skb(dev, &cf);
 339         if (skb == NULL)
 340                 return -ENOMEM;
 341
 342         if (isrc & RMLIS) {
 343                 /* data overrun interrupt */
 344                 netdev_dbg(dev, "data overrun interrupt\n");
 345                 cf->can_id |= CAN_ERR_CRTL;
 346                 cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
 347                 stats->rx_over_errors++;
 348                 stats->rx_errors++;
 349         }
 350
 351         if (isrc & BOIS) {
 352                 netdev_dbg(dev, "bus-off mode interrupt\n");
 353                 state = CAN_STATE_BUS_OFF;
 354                 cf->can_id |= CAN_ERR_BUSOFF;
 355                 can_bus_off(dev);
 356         }
 357
 358         if (isrc & EPIS) {
 359                 /* error passive interrupt */
 360                 netdev_dbg(dev, "error passive interrupt\n");
 361                 state = CAN_STATE_ERROR_PASSIVE;
 362         }
 363
 364         if ((isrc & EWTIS) || (isrc & EWRIS)) {
 365                 netdev_dbg(dev, "Error Warning Transmit/Receive Interrupt\n");
 366                 state = CAN_STATE_ERROR_WARNING;
 367         }
 368
 369         if (state != priv->can.state && (state == CAN_STATE_ERROR_WARNING ||
 370                                 state == CAN_STATE_ERROR_PASSIVE)) {
 371                 u16 cec = bfin_read(&reg->cec);
 372                 u8 rxerr = cec;
 373                 u8 txerr = cec >> 8;
 374
 375                 cf->can_id |= CAN_ERR_CRTL;
 376                 if (state == CAN_STATE_ERROR_WARNING) {
 377                         priv->can.can_stats.error_warning++;
 378                         cf->data[1] = (txerr > rxerr) ?
 379                                 CAN_ERR_CRTL_TX_WARNING :
 380                                 CAN_ERR_CRTL_RX_WARNING;
 381                 } else {
 382                         priv->can.can_stats.error_passive++;
 383                         cf->data[1] = (txerr > rxerr) ?
 384                                 CAN_ERR_CRTL_TX_PASSIVE :
 385                                 CAN_ERR_CRTL_RX_PASSIVE;
 386                 }
 387         }
 388
 389         if (status) {
 390                 priv->can.can_stats.bus_error++;
 391
 392                 cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
 393
 394                 if (status & BEF)
 395                         cf->data[2] |= CAN_ERR_PROT_BIT;
 396                 else if (status & FER)
 397                         cf->data[2] |= CAN_ERR_PROT_FORM;
 398                 else if (status & SER)
 399                         cf->data[2] |= CAN_ERR_PROT_STUFF;
 400                 else
 401                         cf->data[2] |= CAN_ERR_PROT_UNSPEC;
 402         }
 403
 404         priv->can.state = state;
 405
 406         netif_rx(skb);
 407
 408         stats->rx_packets++;
 409         stats->rx_bytes += cf->can_dlc;
 410
 411         return 0;
 412 }
 413
 414 static irqreturn_t bfin_can_interrupt(int irq, void *dev_id)
 415 {
 416         struct net_device *dev = dev_id;
 417         struct bfin_can_priv *priv = netdev_priv(dev);
 418         struct bfin_can_regs __iomem *reg = priv->membase;
 419         struct net_device_stats *stats = &dev->stats;
 420         u16 status, isrc;
 421
 422         if ((irq == priv->tx_irq) && bfin_read(&reg->mbtif2)) {
 423                 /* transmission complete interrupt */
 424                 bfin_write(&reg->mbtif2, 0xFFFF);
 425                 stats->tx_packets++;
 426                 stats->tx_bytes += bfin_read(&reg->chl[TRANSMIT_CHL].dlc);
 427                 can_get_echo_skb(dev, 0);
 428                 netif_wake_queue(dev);
 429         } else if ((irq == priv->rx_irq) && bfin_read(&reg->mbrif1)) {
 430                 /* receive interrupt */
 431                 isrc = bfin_read(&reg->mbrif1);
 432                 bfin_write(&reg->mbrif1, 0xFFFF);
 433                 bfin_can_rx(dev, isrc);
 434         } else if ((irq == priv->err_irq) && bfin_read(&reg->gis)) {
 435                 /* error interrupt */
 436                 isrc = bfin_read(&reg->gis);
 437                 status = bfin_read(&reg->esr);
 438                 bfin_write(&reg->gis, 0x7FF);
 439                 bfin_can_err(dev, isrc, status);
 440         } else {
 441                 return IRQ_NONE;
 442         }
 443
 444         return IRQ_HANDLED;
 445 }
 446
 447 static int bfin_can_open(struct net_device *dev)
 448 {
 449         struct bfin_can_priv *priv = netdev_priv(dev);
 450         int err;
 451
 452         /* set chip into reset mode */
 453         bfin_can_set_reset_mode(dev);
 454
 455         /* common open */
 456         err = open_candev(dev);
 457         if (err)
 458                 goto exit_open;
 459
 460         /* register interrupt handler */
 461         err = request_irq(priv->rx_irq, &bfin_can_interrupt, 0,
 462                         "bfin-can-rx", dev);
 463         if (err)
 464                 goto exit_rx_irq;
 465         err = request_irq(priv->tx_irq, &bfin_can_interrupt, 0,
 466                         "bfin-can-tx", dev);
 467         if (err)
 468                 goto exit_tx_irq;
 469         err = request_irq(priv->err_irq, &bfin_can_interrupt, 0,
 470                         "bfin-can-err", dev);
 471         if (err)
 472                 goto exit_err_irq;
 473
 474         bfin_can_start(dev);
 475
 476         netif_start_queue(dev);
 477
 478         return 0;
 479
 480 exit_err_irq:
 481         free_irq(priv->tx_irq, dev);
 482 exit_tx_irq:
 483         free_irq(priv->rx_irq, dev);
 484 exit_rx_irq:
 485         close_candev(dev);
 486 exit_open:
 487         return err;
 488 }
 489
 490 static int bfin_can_close(struct net_device *dev)
 491 {
 492         struct bfin_can_priv *priv = netdev_priv(dev);
 493
 494         netif_stop_queue(dev);
 495         bfin_can_set_reset_mode(dev);
 496
 497         close_candev(dev);
 498
 499         free_irq(priv->rx_irq, dev);
 500         free_irq(priv->tx_irq, dev);
 501         free_irq(priv->err_irq, dev);
 502
 503         return 0;
 504 }
 505
 506 static struct net_device *alloc_bfin_candev(void)
 507 {
 508         struct net_device *dev;
 509         struct bfin_can_priv *priv;
 510
 511         dev = alloc_candev(sizeof(*priv), TX_ECHO_SKB_MAX);
 512         if (!dev)
 513                 return NULL;
 514
 515         priv = netdev_priv(dev);
 516
 517         priv->dev = dev;
 518         priv->can.bittiming_const = &bfin_can_bittiming_const;
 519         priv->can.do_set_bittiming = bfin_can_set_bittiming;
 520         priv->can.do_set_mode = bfin_can_set_mode;
 521         priv->can.do_get_berr_counter = bfin_can_get_berr_counter;
 522         priv->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES;
 523
 524         return dev;
 525 }
 526
 527 static const struct net_device_ops bfin_can_netdev_ops = {
 528         .ndo_open               = bfin_can_open,
 529         .ndo_stop               = bfin_can_close,
 530         .ndo_start_xmit         = bfin_can_start_xmit,
 531 };
 532
 533 static int bfin_can_probe(struct platform_device *pdev)
 534 {
 535         int err;
 536         struct net_device *dev;
 537         struct bfin_can_priv *priv;
 538         struct resource *res_mem, *rx_irq, *tx_irq, *err_irq;
 539         unsigned short *pdata;
 540
 541         pdata = dev_get_platdata(&pdev->dev);
 542         if (!pdata) {
 543                 dev_err(&pdev->dev, "No platform data provided!\n");
 544                 err = -EINVAL;
 545                 goto exit;
 546         }
 547
 548         res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 549         rx_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 550         tx_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 1);
 551         err_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 2);
 552         if (!res_mem || !rx_irq || !tx_irq || !err_irq) {
 553                 err = -EINVAL;
 554                 goto exit;
 555         }
 556
 557         if (!request_mem_region(res_mem->start, resource_size(res_mem),
 558                                 dev_name(&pdev->dev))) {
 559                 err = -EBUSY;
 560                 goto exit;
 561         }
 562
 563         /* request peripheral pins */
 564         err = peripheral_request_list(pdata, dev_name(&pdev->dev));
 565         if (err)
 566                 goto exit_mem_release;
 567
 568         dev = alloc_bfin_candev();
 569         if (!dev) {
 570                 err = -ENOMEM;
 571                 goto exit_peri_pin_free;
 572         }
 573
 574         priv = netdev_priv(dev);
 575         priv->membase = (void __iomem *)res_mem->start;
 576         priv->rx_irq = rx_irq->start;
 577         priv->tx_irq = tx_irq->start;
 578         priv->err_irq = err_irq->start;
 579         priv->pin_list = pdata;
 580         priv->can.clock.freq = get_sclk();
 581
 582         platform_set_drvdata(pdev, dev);
 583         SET_NETDEV_DEV(dev, &pdev->dev);
 584
 585         dev->flags |= IFF_ECHO; /* we support local echo */
 586         dev->netdev_ops = &bfin_can_netdev_ops;
 587
 588         bfin_can_set_reset_mode(dev);
 589
 590         err = register_candev(dev);
 591         if (err) {
 592                 dev_err(&pdev->dev, "registering failed (err=%d)\n", err);
 593                 goto exit_candev_free;
 594         }
 595
 596         dev_info(&pdev->dev,
 597                 "%s device registered"
 598                 "(&reg_base=%p, rx_irq=%d, tx_irq=%d, err_irq=%d, sclk=%d)\n",
 599                 DRV_NAME, priv->membase, priv->rx_irq,
 600                 priv->tx_irq, priv->err_irq, priv->can.clock.freq);
 601         return 0;
 602
 603 exit_candev_free:
 604         free_candev(dev);
 605 exit_peri_pin_free:
 606         peripheral_free_list(pdata);
 607 exit_mem_release:
 608         release_mem_region(res_mem->start, resource_size(res_mem));
 609 exit:
 610         return err;
 611 }
 612
 613 static int bfin_can_remove(struct platform_device *pdev)
 614 {
 615         struct net_device *dev = platform_get_drvdata(pdev);
 616         struct bfin_can_priv *priv = netdev_priv(dev);
 617         struct resource *res;
 618
 619         bfin_can_set_reset_mode(dev);
 620
 621         unregister_candev(dev);
 622
 623         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 624         release_mem_region(res->start, resource_size(res));
 625
 626         peripheral_free_list(priv->pin_list);
 627
 628         free_candev(dev);
 629         return 0;
 630 }
 631
 632 #ifdef CONFIG_PM
 633 static int bfin_can_suspend(struct platform_device *pdev, pm_message_t mesg)
 634 {
 635         struct net_device *dev = platform_get_drvdata(pdev);
 636         struct bfin_can_priv *priv = netdev_priv(dev);
 637         struct bfin_can_regs __iomem *reg = priv->membase;
 638         int timeout = BFIN_CAN_TIMEOUT;
 639
 640         if (netif_running(dev)) {
 641                 /* enter sleep mode */
 642                 bfin_write(&reg->control, bfin_read(&reg->control) | SMR);
 643                 SSYNC();
 644                 while (!(bfin_read(&reg->intr) & SMACK)) {
 645                         udelay(10);
 646                         if (--timeout == 0) {
 647                                 netdev_err(dev, "fail to enter sleep mode\n");
 648                                 BUG();
 649                         }
 650                 }
 651         }
 652
 653         return 0;
 654 }
 655
 656 static int bfin_can_resume(struct platform_device *pdev)
 657 {
 658         struct net_device *dev = platform_get_drvdata(pdev);
 659         struct bfin_can_priv *priv = netdev_priv(dev);
 660         struct bfin_can_regs __iomem *reg = priv->membase;
 661
 662         if (netif_running(dev)) {
 663                 /* leave sleep mode */
 664                 bfin_write(&reg->intr, 0);
 665                 SSYNC();
 666         }
 667
 668         return 0;
 669 }
 670 #else
 671 #define bfin_can_suspend NULL
 672 #define bfin_can_resume NULL
 673 #endif  /* CONFIG_PM */
 674
 675 static struct platform_driver bfin_can_driver = {
 676         .probe = bfin_can_probe,
 677         .remove = bfin_can_remove,
 678         .suspend = bfin_can_suspend,
 679         .resume = bfin_can_resume,
 680         .driver = {
 681                 .name = DRV_NAME,
 682                 .owner = THIS_MODULE,
 683         },
 684 };
 685
 686 module_platform_driver(bfin_can_driver);
 687
 688 MODULE_AUTHOR("Barry Song <21cnbao@gmail.com>");
 689 MODULE_LICENSE("GPL");
 690 MODULE_DESCRIPTION("Blackfin on-chip CAN netdevice driver");
 691 MODULE_ALIAS("platform:" DRV_NAME);