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