drivers/net/can/mscan/mscan.c

   1 /*
   2  * CAN bus driver for the alone generic (as possible as) MSCAN controller.
   3  *
   4  * Copyright (C) 2005-2006 Andrey Volkov <avolkov@varma-el.com>,
   5  *                         Varma Electronics Oy
   6  * Copyright (C) 2008-2009 Wolfgang Grandegger <wg@grandegger.com>
   7  * Copyright (C) 2008-2009 Pengutronix <kernel@pengutronix.de>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the version 2 of the GNU General Public License
  11  * as published by the Free Software Foundation
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21  */
  22
  23 #include <linux/kernel.h>
  24 #include <linux/module.h>
  25 #include <linux/interrupt.h>
  26 #include <linux/delay.h>
  27 #include <linux/netdevice.h>
  28 #include <linux/if_arp.h>
  29 #include <linux/if_ether.h>
  30 #include <linux/list.h>
  31 #include <linux/can/dev.h>
  32 #include <linux/can/error.h>
  33 #include <linux/io.h>
  34
  35 #include "mscan.h"
  36
  37 static struct can_bittiming_const mscan_bittiming_const = {
  38         .name = "mscan",
  39         .tseg1_min = 4,
  40         .tseg1_max = 16,
  41         .tseg2_min = 2,
  42         .tseg2_max = 8,
  43         .sjw_max = 4,
  44         .brp_min = 1,
  45         .brp_max = 64,
  46         .brp_inc = 1,
  47 };
  48
  49 struct mscan_state {
  50         u8 mode;
  51         u8 canrier;
  52         u8 cantier;
  53 };
  54
  55 static enum can_state state_map[] = {
  56         CAN_STATE_ERROR_ACTIVE,
  57         CAN_STATE_ERROR_WARNING,
  58         CAN_STATE_ERROR_PASSIVE,
  59         CAN_STATE_BUS_OFF
  60 };
  61
  62 static int mscan_set_mode(struct net_device *dev, u8 mode)
  63 {
  64         struct mscan_priv *priv = netdev_priv(dev);
  65         struct mscan_regs __iomem *regs = priv->reg_base;
  66         int ret = 0;
  67         int i;
  68         u8 canctl1;
  69
  70         if (mode != MSCAN_NORMAL_MODE) {
  71                 if (priv->tx_active) {
  72                         /* Abort transfers before going to sleep */#
  73                         out_8(&regs->cantarq, priv->tx_active);
  74                         /* Suppress TX done interrupts */
  75                         out_8(&regs->cantier, 0);
  76                 }
  77
  78                 canctl1 = in_8(&regs->canctl1);
  79                 if ((mode & MSCAN_SLPRQ) && !(canctl1 & MSCAN_SLPAK)) {
  80                         setbits8(&regs->canctl0, MSCAN_SLPRQ);
  81                         for (i = 0; i < MSCAN_SET_MODE_RETRIES; i++) {
  82                                 if (in_8(&regs->canctl1) & MSCAN_SLPAK)
  83                                         break;
  84                                 udelay(100);
  85                         }
  86                         /*
  87                          * The mscan controller will fail to enter sleep mode,
  88                          * while there are irregular activities on bus, like
  89                          * somebody keeps retransmitting. This behavior is
  90                          * undocumented and seems to differ between mscan built
  91                          * in mpc5200b and mpc5200. We proceed in that case,
  92                          * since otherwise the slprq will be kept set and the
  93                          * controller will get stuck. NOTE: INITRQ or CSWAI
  94                          * will abort all active transmit actions, if still
  95                          * any, at once.
  96                          */
  97                         if (i >= MSCAN_SET_MODE_RETRIES)
  98                                 dev_dbg(dev->dev.parent,
  99                                         "device failed to enter sleep mode. "
 100                                         "We proceed anyhow.\n");
 101                         else
 102                                 priv->can.state = CAN_STATE_SLEEPING;
 103                 }
 104
 105                 if ((mode & MSCAN_INITRQ) && !(canctl1 & MSCAN_INITAK)) {
 106                         setbits8(&regs->canctl0, MSCAN_INITRQ);
 107                         for (i = 0; i < MSCAN_SET_MODE_RETRIES; i++) {
 108                                 if (in_8(&regs->canctl1) & MSCAN_INITAK)
 109                                         break;
 110                         }
 111                         if (i >= MSCAN_SET_MODE_RETRIES)
 112                                 ret = -ENODEV;
 113                 }
 114                 if (!ret)
 115                         priv->can.state = CAN_STATE_STOPPED;
 116
 117                 if (mode & MSCAN_CSWAI)
 118                         setbits8(&regs->canctl0, MSCAN_CSWAI);
 119
 120         } else {
 121                 canctl1 = in_8(&regs->canctl1);
 122                 if (canctl1 & (MSCAN_SLPAK | MSCAN_INITAK)) {
 123                         clrbits8(&regs->canctl0, MSCAN_SLPRQ | MSCAN_INITRQ);
 124                         for (i = 0; i < MSCAN_SET_MODE_RETRIES; i++) {
 125                                 canctl1 = in_8(&regs->canctl1);
 126                                 if (!(canctl1 & (MSCAN_INITAK | MSCAN_SLPAK)))
 127                                         break;
 128                         }
 129                         if (i >= MSCAN_SET_MODE_RETRIES)
 130                                 ret = -ENODEV;
 131                         else
 132                                 priv->can.state = CAN_STATE_ERROR_ACTIVE;
 133                 }
 134         }
 135         return ret;
 136 }
 137
 138 static int mscan_start(struct net_device *dev)
 139 {
 140         struct mscan_priv *priv = netdev_priv(dev);
 141         struct mscan_regs __iomem *regs = priv->reg_base;
 142         u8 canrflg;
 143         int err;
 144
 145         out_8(&regs->canrier, 0);
 146
 147         INIT_LIST_HEAD(&priv->tx_head);
 148         priv->prev_buf_id = 0;
 149         priv->cur_pri = 0;
 150         priv->tx_active = 0;
 151         priv->shadow_canrier = 0;
 152         priv->flags = 0;
 153
 154         if (priv->type == MSCAN_TYPE_MPC5121) {
 155                 /* Clear pending bus-off condition */
 156                 if (in_8(&regs->canmisc) & MSCAN_BOHOLD)
 157                         out_8(&regs->canmisc, MSCAN_BOHOLD);
 158         }
 159
 160         err = mscan_set_mode(dev, MSCAN_NORMAL_MODE);
 161         if (err)
 162                 return err;
 163
 164         canrflg = in_8(&regs->canrflg);
 165         priv->shadow_statflg = canrflg & MSCAN_STAT_MSK;
 166         priv->can.state = state_map[max(MSCAN_STATE_RX(canrflg),
 167                                     MSCAN_STATE_TX(canrflg))];
 168         out_8(&regs->cantier, 0);
 169
 170         /* Enable receive interrupts. */
 171         out_8(&regs->canrier, MSCAN_RX_INTS_ENABLE);
 172
 173         return 0;
 174 }
 175
 176 static int mscan_restart(struct net_device *dev)
 177 {
 178         struct mscan_priv *priv = netdev_priv(dev);
 179
 180         if (priv->type == MSCAN_TYPE_MPC5121) {
 181                 struct mscan_regs __iomem *regs = priv->reg_base;
 182
 183                 priv->can.state = CAN_STATE_ERROR_ACTIVE;
 184                 WARN(!(in_8(&regs->canmisc) & MSCAN_BOHOLD),
 185                      "bus-off state expected\n");
 186                 out_8(&regs->canmisc, MSCAN_BOHOLD);
 187                 /* Re-enable receive interrupts. */
 188                 out_8(&regs->canrier, MSCAN_RX_INTS_ENABLE);
 189         } else {
 190                 if (priv->can.state <= CAN_STATE_BUS_OFF)
 191                         mscan_set_mode(dev, MSCAN_INIT_MODE);
 192                 return mscan_start(dev);
 193         }
 194
 195         return 0;
 196 }
 197
 198 static netdev_tx_t mscan_start_xmit(struct sk_buff *skb, struct net_device *dev)
 199 {
 200         struct can_frame *frame = (struct can_frame *)skb->data;
 201         struct mscan_priv *priv = netdev_priv(dev);
 202         struct mscan_regs __iomem *regs = priv->reg_base;
 203         int i, rtr, buf_id;
 204         u32 can_id;
 205
 206         if (can_dropped_invalid_skb(dev, skb))
 207                 return NETDEV_TX_OK;
 208
 209         out_8(&regs->cantier, 0);
 210
 211         i = ~priv->tx_active & MSCAN_TXE;
 212         buf_id = ffs(i) - 1;
 213         switch (hweight8(i)) {
 214         case 0:
 215                 netif_stop_queue(dev);
 216                 dev_err(dev->dev.parent, "Tx Ring full when queue awake!\n");
 217                 return NETDEV_TX_BUSY;
 218         case 1:
 219                 /*
 220                  * if buf_id < 3, then current frame will be send out of order,
 221                  * since buffer with lower id have higher priority (hell..)
 222                  */
 223                 netif_stop_queue(dev);
 224         case 2:
 225                 if (buf_id < priv->prev_buf_id) {
 226                         priv->cur_pri++;
 227                         if (priv->cur_pri == 0xff) {
 228                                 set_bit(F_TX_WAIT_ALL, &priv->flags);
 229                                 netif_stop_queue(dev);
 230                         }
 231                 }
 232                 set_bit(F_TX_PROGRESS, &priv->flags);
 233                 break;
 234         }
 235         priv->prev_buf_id = buf_id;
 236         out_8(&regs->cantbsel, i);
 237
 238         rtr = frame->can_id & CAN_RTR_FLAG;
 239
 240         /* RTR is always the lowest bit of interest, then IDs follow */
 241         if (frame->can_id & CAN_EFF_FLAG) {
 242                 can_id = (frame->can_id & CAN_EFF_MASK)
 243                          << (MSCAN_EFF_RTR_SHIFT + 1);
 244                 if (rtr)
 245                         can_id |= 1 << MSCAN_EFF_RTR_SHIFT;
 246                 out_be16(&regs->tx.idr3_2, can_id);
 247
 248                 can_id >>= 16;
 249                 /* EFF_FLAGS are between the IDs :( */
 250                 can_id = (can_id & 0x7) | ((can_id << 2) & 0xffe0)
 251                          | MSCAN_EFF_FLAGS;
 252         } else {
 253                 can_id = (frame->can_id & CAN_SFF_MASK)
 254                          << (MSCAN_SFF_RTR_SHIFT + 1);
 255                 if (rtr)
 256                         can_id |= 1 << MSCAN_SFF_RTR_SHIFT;
 257         }
 258         out_be16(&regs->tx.idr1_0, can_id);
 259
 260         if (!rtr) {
 261                 void __iomem *data = &regs->tx.dsr1_0;
 262                 u16 *payload = (u16 *)frame->data;
 263
 264                 for (i = 0; i < frame->can_dlc / 2; i++) {
 265                         out_be16(data, *payload++);
 266                         data += 2 + _MSCAN_RESERVED_DSR_SIZE;
 267                 }
 268                 /* write remaining byte if necessary */
 269                 if (frame->can_dlc & 1)
 270                         out_8(data, frame->data[frame->can_dlc - 1]);
 271         }
 272
 273         out_8(&regs->tx.dlr, frame->can_dlc);
 274         out_8(&regs->tx.tbpr, priv->cur_pri);
 275
 276         /* Start transmission. */
 277         out_8(&regs->cantflg, 1 << buf_id);
 278
 279         if (!test_bit(F_TX_PROGRESS, &priv->flags))
 280                 dev->trans_start = jiffies;
 281
 282         list_add_tail(&priv->tx_queue[buf_id].list, &priv->tx_head);
 283
 284         can_put_echo_skb(skb, dev, buf_id);
 285
 286         /* Enable interrupt. */
 287         priv->tx_active |= 1 << buf_id;
 288         out_8(&regs->cantier, priv->tx_active);
 289
 290         return NETDEV_TX_OK;
 291 }
 292
 293 /* This function returns the old state to see where we came from */
 294 static enum can_state check_set_state(struct net_device *dev, u8 canrflg)
 295 {
 296         struct mscan_priv *priv = netdev_priv(dev);
 297         enum can_state state, old_state = priv->can.state;
 298
 299         if (canrflg & MSCAN_CSCIF && old_state <= CAN_STATE_BUS_OFF) {
 300                 state = state_map[max(MSCAN_STATE_RX(canrflg),
 301                                       MSCAN_STATE_TX(canrflg))];
 302                 priv->can.state = state;
 303         }
 304         return old_state;
 305 }
 306
 307 static void mscan_get_rx_frame(struct net_device *dev, struct can_frame *frame)
 308 {
 309         struct mscan_priv *priv = netdev_priv(dev);
 310         struct mscan_regs __iomem *regs = priv->reg_base;
 311         u32 can_id;
 312         int i;
 313
 314         can_id = in_be16(&regs->rx.idr1_0);
 315         if (can_id & (1 << 3)) {
 316                 frame->can_id = CAN_EFF_FLAG;
 317                 can_id = ((can_id << 16) | in_be16(&regs->rx.idr3_2));
 318                 can_id = ((can_id & 0xffe00000) |
 319                           ((can_id & 0x7ffff) << 2)) >> 2;
 320         } else {
 321                 can_id >>= 4;
 322                 frame->can_id = 0;
 323         }
 324
 325         frame->can_id |= can_id >> 1;
 326         if (can_id & 1)
 327                 frame->can_id |= CAN_RTR_FLAG;
 328
 329         frame->can_dlc = get_can_dlc(in_8(&regs->rx.dlr) & 0xf);
 330
 331         if (!(frame->can_id & CAN_RTR_FLAG)) {
 332                 void __iomem *data = &regs->rx.dsr1_0;
 333                 u16 *payload = (u16 *)frame->data;
 334
 335                 for (i = 0; i < frame->can_dlc / 2; i++) {
 336                         *payload++ = in_be16(data);
 337                         data += 2 + _MSCAN_RESERVED_DSR_SIZE;
 338                 }
 339                 /* read remaining byte if necessary */
 340                 if (frame->can_dlc & 1)
 341                         frame->data[frame->can_dlc - 1] = in_8(data);
 342         }
 343
 344         out_8(&regs->canrflg, MSCAN_RXF);
 345 }
 346
 347 static void mscan_get_err_frame(struct net_device *dev, struct can_frame *frame,
 348                                 u8 canrflg)
 349 {
 350         struct mscan_priv *priv = netdev_priv(dev);
 351         struct mscan_regs __iomem *regs = priv->reg_base;
 352         struct net_device_stats *stats = &dev->stats;
 353         enum can_state old_state;
 354
 355         dev_dbg(dev->dev.parent, "error interrupt (canrflg=%#x)\n", canrflg);
 356         frame->can_id = CAN_ERR_FLAG;
 357
 358         if (canrflg & MSCAN_OVRIF) {
 359                 frame->can_id |= CAN_ERR_CRTL;
 360                 frame->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
 361                 stats->rx_over_errors++;
 362                 stats->rx_errors++;
 363         } else {
 364                 frame->data[1] = 0;
 365         }
 366
 367         old_state = check_set_state(dev, canrflg);
 368         /* State changed */
 369         if (old_state != priv->can.state) {
 370                 switch (priv->can.state) {
 371                 case CAN_STATE_ERROR_WARNING:
 372                         frame->can_id |= CAN_ERR_CRTL;
 373                         priv->can.can_stats.error_warning++;
 374                         if ((priv->shadow_statflg & MSCAN_RSTAT_MSK) <
 375                             (canrflg & MSCAN_RSTAT_MSK))
 376                                 frame->data[1] |= CAN_ERR_CRTL_RX_WARNING;
 377                         if ((priv->shadow_statflg & MSCAN_TSTAT_MSK) <
 378                             (canrflg & MSCAN_TSTAT_MSK))
 379                                 frame->data[1] |= CAN_ERR_CRTL_TX_WARNING;
 380                         break;
 381                 case CAN_STATE_ERROR_PASSIVE:
 382                         frame->can_id |= CAN_ERR_CRTL;
 383                         priv->can.can_stats.error_passive++;
 384                         frame->data[1] |= CAN_ERR_CRTL_RX_PASSIVE;
 385                         break;
 386                 case CAN_STATE_BUS_OFF:
 387                         frame->can_id |= CAN_ERR_BUSOFF;
 388                         /*
 389                          * The MSCAN on the MPC5200 does recover from bus-off
 390                          * automatically. To avoid that we stop the chip doing
 391                          * a light-weight stop (we are in irq-context).
 392                          */
 393                         if (priv->type != MSCAN_TYPE_MPC5121) {
 394                                 out_8(&regs->cantier, 0);
 395                                 out_8(&regs->canrier, 0);
 396                                 setbits8(&regs->canctl0,
 397                                          MSCAN_SLPRQ | MSCAN_INITRQ);
 398                         }
 399                         can_bus_off(dev);
 400                         break;
 401                 default:
 402                         break;
 403                 }
 404         }
 405         priv->shadow_statflg = canrflg & MSCAN_STAT_MSK;
 406         frame->can_dlc = CAN_ERR_DLC;
 407         out_8(&regs->canrflg, MSCAN_ERR_IF);
 408 }
 409
 410 static int mscan_rx_poll(struct napi_struct *napi, int quota)
 411 {
 412         struct mscan_priv *priv = container_of(napi, struct mscan_priv, napi);
 413         struct net_device *dev = napi->dev;
 414         struct mscan_regs __iomem *regs = priv->reg_base;
 415         struct net_device_stats *stats = &dev->stats;
 416         int npackets = 0;
 417         int ret = 1;
 418         struct sk_buff *skb;
 419         struct can_frame *frame;
 420         u8 canrflg;
 421
 422         while (npackets < quota) {
 423                 canrflg = in_8(&regs->canrflg);
 424                 if (!(canrflg & (MSCAN_RXF | MSCAN_ERR_IF)))
 425                         break;
 426
 427                 skb = alloc_can_skb(dev, &frame);
 428                 if (!skb) {
 429                         if (printk_ratelimit())
 430                                 dev_notice(dev->dev.parent, "packet dropped\n");
 431                         stats->rx_dropped++;
 432                         out_8(&regs->canrflg, canrflg);
 433                         continue;
 434                 }
 435
 436                 if (canrflg & MSCAN_RXF)
 437                         mscan_get_rx_frame(dev, frame);
 438                 else if (canrflg & MSCAN_ERR_IF)
 439                         mscan_get_err_frame(dev, frame, canrflg);
 440
 441                 stats->rx_packets++;
 442                 stats->rx_bytes += frame->can_dlc;
 443                 npackets++;
 444                 netif_receive_skb(skb);
 445         }
 446
 447         if (!(in_8(&regs->canrflg) & (MSCAN_RXF | MSCAN_ERR_IF))) {
 448                 napi_complete(&priv->napi);
 449                 clear_bit(F_RX_PROGRESS, &priv->flags);
 450                 if (priv->can.state < CAN_STATE_BUS_OFF)
 451                         out_8(&regs->canrier, priv->shadow_canrier);
 452                 ret = 0;
 453         }
 454         return ret;
 455 }
 456
 457 static irqreturn_t mscan_isr(int irq, void *dev_id)
 458 {
 459         struct net_device *dev = (struct net_device *)dev_id;
 460         struct mscan_priv *priv = netdev_priv(dev);
 461         struct mscan_regs __iomem *regs = priv->reg_base;
 462         struct net_device_stats *stats = &dev->stats;
 463         u8 cantier, cantflg, canrflg;
 464         irqreturn_t ret = IRQ_NONE;
 465
 466         cantier = in_8(&regs->cantier) & MSCAN_TXE;
 467         cantflg = in_8(&regs->cantflg) & cantier;
 468
 469         if (cantier && cantflg) {
 470                 struct list_head *tmp, *pos;
 471
 472                 list_for_each_safe(pos, tmp, &priv->tx_head) {
 473                         struct tx_queue_entry *entry =
 474                             list_entry(pos, struct tx_queue_entry, list);
 475                         u8 mask = entry->mask;
 476
 477                         if (!(cantflg & mask))
 478                                 continue;
 479
 480                         out_8(&regs->cantbsel, mask);
 481                         stats->tx_bytes += in_8(&regs->tx.dlr);
 482                         stats->tx_packets++;
 483                         can_get_echo_skb(dev, entry->id);
 484                         priv->tx_active &= ~mask;
 485                         list_del(pos);
 486                 }
 487
 488                 if (list_empty(&priv->tx_head)) {
 489                         clear_bit(F_TX_WAIT_ALL, &priv->flags);
 490                         clear_bit(F_TX_PROGRESS, &priv->flags);
 491                         priv->cur_pri = 0;
 492                 } else {
 493                         dev->trans_start = jiffies;
 494                 }
 495
 496                 if (!test_bit(F_TX_WAIT_ALL, &priv->flags))
 497                         netif_wake_queue(dev);
 498
 499                 out_8(&regs->cantier, priv->tx_active);
 500                 ret = IRQ_HANDLED;
 501         }
 502
 503         canrflg = in_8(&regs->canrflg);
 504         if ((canrflg & ~MSCAN_STAT_MSK) &&
 505             !test_and_set_bit(F_RX_PROGRESS, &priv->flags)) {
 506                 if (canrflg & ~MSCAN_STAT_MSK) {
 507                         priv->shadow_canrier = in_8(&regs->canrier);
 508                         out_8(&regs->canrier, 0);
 509                         napi_schedule(&priv->napi);
 510                         ret = IRQ_HANDLED;
 511                 } else {
 512                         clear_bit(F_RX_PROGRESS, &priv->flags);
 513                 }
 514         }
 515         return ret;
 516 }
 517
 518 static int mscan_do_set_mode(struct net_device *dev, enum can_mode mode)
 519 {
 520         struct mscan_priv *priv = netdev_priv(dev);
 521         int ret = 0;
 522
 523         if (!priv->open_time)
 524                 return -EINVAL;
 525
 526         switch (mode) {
 527         case CAN_MODE_START:
 528                 ret = mscan_restart(dev);
 529                 if (ret)
 530                         break;
 531                 if (netif_queue_stopped(dev))
 532                         netif_wake_queue(dev);
 533                 break;
 534
 535         default:
 536                 ret = -EOPNOTSUPP;
 537                 break;
 538         }
 539         return ret;
 540 }
 541
 542 static int mscan_do_set_bittiming(struct net_device *dev)
 543 {
 544         struct mscan_priv *priv = netdev_priv(dev);
 545         struct mscan_regs __iomem *regs = priv->reg_base;
 546         struct can_bittiming *bt = &priv->can.bittiming;
 547         u8 btr0, btr1;
 548
 549         btr0 = BTR0_SET_BRP(bt->brp) | BTR0_SET_SJW(bt->sjw);
 550         btr1 = (BTR1_SET_TSEG1(bt->prop_seg + bt->phase_seg1) |
 551                 BTR1_SET_TSEG2(bt->phase_seg2) |
 552                 BTR1_SET_SAM(priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES));
 553
 554         dev_info(dev->dev.parent, "setting BTR0=0x%02x BTR1=0x%02x\n",
 555                 btr0, btr1);
 556
 557         out_8(&regs->canbtr0, btr0);
 558         out_8(&regs->canbtr1, btr1);
 559
 560         return 0;
 561 }
 562
 563 static int mscan_open(struct net_device *dev)
 564 {
 565         int ret;
 566         struct mscan_priv *priv = netdev_priv(dev);
 567         struct mscan_regs __iomem *regs = priv->reg_base;
 568
 569         /* common open */
 570         ret = open_candev(dev);
 571         if (ret)
 572                 return ret;
 573
 574         napi_enable(&priv->napi);
 575
 576         ret = request_irq(dev->irq, mscan_isr, 0, dev->name, dev);
 577         if (ret < 0) {
 578                 dev_err(dev->dev.parent, "failed to attach interrupt\n");
 579                 goto exit_napi_disable;
 580         }
 581
 582         priv->open_time = jiffies;
 583
 584         if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
 585                 setbits8(&regs->canctl1, MSCAN_LISTEN);
 586         else
 587                 clrbits8(&regs->canctl1, MSCAN_LISTEN);
 588
 589         ret = mscan_start(dev);
 590         if (ret)
 591                 goto exit_free_irq;
 592
 593         netif_start_queue(dev);
 594
 595         return 0;
 596
 597 exit_free_irq:
 598         priv->open_time = 0;
 599         free_irq(dev->irq, dev);
 600 exit_napi_disable:
 601         napi_disable(&priv->napi);
 602         close_candev(dev);
 603         return ret;
 604 }
 605
 606 static int mscan_close(struct net_device *dev)
 607 {
 608         struct mscan_priv *priv = netdev_priv(dev);
 609         struct mscan_regs __iomem *regs = priv->reg_base;
 610
 611         netif_stop_queue(dev);
 612         napi_disable(&priv->napi);
 613
 614         out_8(&regs->cantier, 0);
 615         out_8(&regs->canrier, 0);
 616         mscan_set_mode(dev, MSCAN_INIT_MODE);
 617         close_candev(dev);
 618         free_irq(dev->irq, dev);
 619         priv->open_time = 0;
 620
 621         return 0;
 622 }
 623
 624 static const struct net_device_ops mscan_netdev_ops = {
 625        .ndo_open               = mscan_open,
 626        .ndo_stop               = mscan_close,
 627        .ndo_start_xmit         = mscan_start_xmit,
 628 };
 629
 630 int register_mscandev(struct net_device *dev, int mscan_clksrc)
 631 {
 632         struct mscan_priv *priv = netdev_priv(dev);
 633         struct mscan_regs __iomem *regs = priv->reg_base;
 634         u8 ctl1;
 635
 636         ctl1 = in_8(&regs->canctl1);
 637         if (mscan_clksrc)
 638                 ctl1 |= MSCAN_CLKSRC;
 639         else
 640                 ctl1 &= ~MSCAN_CLKSRC;
 641
 642         if (priv->type == MSCAN_TYPE_MPC5121)
 643                 ctl1 |= MSCAN_BORM; /* bus-off recovery upon request */
 644
 645         ctl1 |= MSCAN_CANE;
 646         out_8(&regs->canctl1, ctl1);
 647         udelay(100);
 648
 649         /* acceptance mask/acceptance code (accept everything) */
 650         out_be16(&regs->canidar1_0, 0);
 651         out_be16(&regs->canidar3_2, 0);
 652         out_be16(&regs->canidar5_4, 0);
 653         out_be16(&regs->canidar7_6, 0);
 654
 655         out_be16(&regs->canidmr1_0, 0xffff);
 656         out_be16(&regs->canidmr3_2, 0xffff);
 657         out_be16(&regs->canidmr5_4, 0xffff);
 658         out_be16(&regs->canidmr7_6, 0xffff);
 659         /* Two 32 bit Acceptance Filters */
 660         out_8(&regs->canidac, MSCAN_AF_32BIT);
 661
 662         mscan_set_mode(dev, MSCAN_INIT_MODE);
 663
 664         return register_candev(dev);
 665 }
 666
 667 void unregister_mscandev(struct net_device *dev)
 668 {
 669         struct mscan_priv *priv = netdev_priv(dev);
 670         struct mscan_regs __iomem *regs = priv->reg_base;
 671         mscan_set_mode(dev, MSCAN_INIT_MODE);
 672         clrbits8(&regs->canctl1, MSCAN_CANE);
 673         unregister_candev(dev);
 674 }
 675
 676 struct net_device *alloc_mscandev(void)
 677 {
 678         struct net_device *dev;
 679         struct mscan_priv *priv;
 680         int i;
 681
 682         dev = alloc_candev(sizeof(struct mscan_priv), MSCAN_ECHO_SKB_MAX);
 683         if (!dev)
 684                 return NULL;
 685         priv = netdev_priv(dev);
 686
 687         dev->netdev_ops = &mscan_netdev_ops;
 688
 689         dev->flags |= IFF_ECHO; /* we support local echo */
 690
 691         netif_napi_add(dev, &priv->napi, mscan_rx_poll, 8);
 692
 693         priv->can.bittiming_const = &mscan_bittiming_const;
 694         priv->can.do_set_bittiming = mscan_do_set_bittiming;
 695         priv->can.do_set_mode = mscan_do_set_mode;
 696         priv->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES |
 697                 CAN_CTRLMODE_LISTENONLY;
 698
 699         for (i = 0; i < TX_QUEUE_SIZE; i++) {
 700                 priv->tx_queue[i].id = i;
 701                 priv->tx_queue[i].mask = 1 << i;
 702         }
 703
 704         return dev;
 705 }
 706
 707 MODULE_AUTHOR("Andrey Volkov <avolkov@varma-el.com>");
 708 MODULE_LICENSE("GPL v2");
 709 MODULE_DESCRIPTION("CAN port driver for a MSCAN based chips");