drivers/net/can/c_can/c_can.c

   1 /*
   2  * CAN bus driver for Bosch C_CAN controller
   3  *
   4  * Copyright (C) 2010 ST Microelectronics
   5  * Bhupesh Sharma <bhupesh.sharma@st.com>
   6  *
   7  * Borrowed heavily from the C_CAN driver originally written by:
   8  * Copyright (C) 2007
   9  * - Sascha Hauer, Marc Kleine-Budde, Pengutronix <s.hauer@pengutronix.de>
  10  * - Simon Kallweit, intefo AG <simon.kallweit@intefo.ch>
  11  *
  12  * TX and RX NAPI implementation has been borrowed from at91 CAN driver
  13  * written by:
  14  * Copyright
  15  * (C) 2007 by Hans J. Koch <hjk@hansjkoch.de>
  16  * (C) 2008, 2009 by Marc Kleine-Budde <kernel@pengutronix.de>
  17  *
  18  * Bosch C_CAN controller is compliant to CAN protocol version 2.0 part A and B.
  19  * Bosch C_CAN user manual can be obtained from:
  20  * http://www.semiconductors.bosch.de/media/en/pdf/ipmodules_1/c_can/
  21  * users_manual_c_can.pdf
  22  *
  23  * This file is licensed under the terms of the GNU General Public
  24  * License version 2. This program is licensed "as is" without any
  25  * warranty of any kind, whether express or implied.
  26  */
  27
  28 #include <linux/kernel.h>
  29 #include <linux/module.h>
  30 #include <linux/interrupt.h>
  31 #include <linux/delay.h>
  32 #include <linux/netdevice.h>
  33 #include <linux/if_arp.h>
  34 #include <linux/if_ether.h>
  35 #include <linux/list.h>
  36 #include <linux/io.h>
  37
  38 #include <linux/can.h>
  39 #include <linux/can/dev.h>
  40 #include <linux/can/error.h>
  41
  42 #include "c_can.h"
  43
  44 /* control register */
  45 #define CONTROL_TEST            BIT(7)
  46 #define CONTROL_CCE             BIT(6)
  47 #define CONTROL_DISABLE_AR      BIT(5)
  48 #define CONTROL_ENABLE_AR       (0 << 5)
  49 #define CONTROL_EIE             BIT(3)
  50 #define CONTROL_SIE             BIT(2)
  51 #define CONTROL_IE              BIT(1)
  52 #define CONTROL_INIT            BIT(0)
  53
  54 /* test register */
  55 #define TEST_RX                 BIT(7)
  56 #define TEST_TX1                BIT(6)
  57 #define TEST_TX2                BIT(5)
  58 #define TEST_LBACK              BIT(4)
  59 #define TEST_SILENT             BIT(3)
  60 #define TEST_BASIC              BIT(2)
  61
  62 /* status register */
  63 #define STATUS_BOFF             BIT(7)
  64 #define STATUS_EWARN            BIT(6)
  65 #define STATUS_EPASS            BIT(5)
  66 #define STATUS_RXOK             BIT(4)
  67 #define STATUS_TXOK             BIT(3)
  68
  69 /* error counter register */
  70 #define ERR_CNT_TEC_MASK        0xff
  71 #define ERR_CNT_TEC_SHIFT       0
  72 #define ERR_CNT_REC_SHIFT       8
  73 #define ERR_CNT_REC_MASK        (0x7f << ERR_CNT_REC_SHIFT)
  74 #define ERR_CNT_RP_SHIFT        15
  75 #define ERR_CNT_RP_MASK         (0x1 << ERR_CNT_RP_SHIFT)
  76
  77 /* bit-timing register */
  78 #define BTR_BRP_MASK            0x3f
  79 #define BTR_BRP_SHIFT           0
  80 #define BTR_SJW_SHIFT           6
  81 #define BTR_SJW_MASK            (0x3 << BTR_SJW_SHIFT)
  82 #define BTR_TSEG1_SHIFT         8
  83 #define BTR_TSEG1_MASK          (0xf << BTR_TSEG1_SHIFT)
  84 #define BTR_TSEG2_SHIFT         12
  85 #define BTR_TSEG2_MASK          (0x7 << BTR_TSEG2_SHIFT)
  86
  87 /* brp extension register */
  88 #define BRP_EXT_BRPE_MASK       0x0f
  89 #define BRP_EXT_BRPE_SHIFT      0
  90
  91 /* IFx command request */
  92 #define IF_COMR_BUSY            BIT(15)
  93
  94 /* IFx command mask */
  95 #define IF_COMM_WR              BIT(7)
  96 #define IF_COMM_MASK            BIT(6)
  97 #define IF_COMM_ARB             BIT(5)
  98 #define IF_COMM_CONTROL         BIT(4)
  99 #define IF_COMM_CLR_INT_PND     BIT(3)
 100 #define IF_COMM_TXRQST          BIT(2)
 101 #define IF_COMM_DATAA           BIT(1)
 102 #define IF_COMM_DATAB           BIT(0)
 103 #define IF_COMM_ALL             (IF_COMM_MASK | IF_COMM_ARB | \
 104                                 IF_COMM_CONTROL | IF_COMM_TXRQST | \
 105                                 IF_COMM_DATAA | IF_COMM_DATAB)
 106
 107 /* IFx arbitration */
 108 #define IF_ARB_MSGVAL           BIT(15)
 109 #define IF_ARB_MSGXTD           BIT(14)
 110 #define IF_ARB_TRANSMIT         BIT(13)
 111
 112 /* IFx message control */
 113 #define IF_MCONT_NEWDAT         BIT(15)
 114 #define IF_MCONT_MSGLST         BIT(14)
 115 #define IF_MCONT_CLR_MSGLST     (0 << 14)
 116 #define IF_MCONT_INTPND         BIT(13)
 117 #define IF_MCONT_UMASK          BIT(12)
 118 #define IF_MCONT_TXIE           BIT(11)
 119 #define IF_MCONT_RXIE           BIT(10)
 120 #define IF_MCONT_RMTEN          BIT(9)
 121 #define IF_MCONT_TXRQST         BIT(8)
 122 #define IF_MCONT_EOB            BIT(7)
 123 #define IF_MCONT_DLC_MASK       0xf
 124
 125 /*
 126  * IFx register masks:
 127  * allow easy operation on 16-bit registers when the
 128  * argument is 32-bit instead
 129  */
 130 #define IFX_WRITE_LOW_16BIT(x)  ((x) & 0xFFFF)
 131 #define IFX_WRITE_HIGH_16BIT(x) (((x) & 0xFFFF0000) >> 16)
 132
 133 /* message object split */
 134 #define C_CAN_NO_OF_OBJECTS     32
 135 #define C_CAN_MSG_OBJ_RX_NUM    16
 136 #define C_CAN_MSG_OBJ_TX_NUM    16
 137
 138 #define C_CAN_MSG_OBJ_RX_FIRST  1
 139 #define C_CAN_MSG_OBJ_RX_LAST   (C_CAN_MSG_OBJ_RX_FIRST + \
 140                                 C_CAN_MSG_OBJ_RX_NUM - 1)
 141
 142 #define C_CAN_MSG_OBJ_TX_FIRST  (C_CAN_MSG_OBJ_RX_LAST + 1)
 143 #define C_CAN_MSG_OBJ_TX_LAST   (C_CAN_MSG_OBJ_TX_FIRST + \
 144                                 C_CAN_MSG_OBJ_TX_NUM - 1)
 145
 146 #define C_CAN_MSG_OBJ_RX_SPLIT  9
 147 #define C_CAN_MSG_RX_LOW_LAST   (C_CAN_MSG_OBJ_RX_SPLIT - 1)
 148
 149 #define C_CAN_NEXT_MSG_OBJ_MASK (C_CAN_MSG_OBJ_TX_NUM - 1)
 150 #define RECEIVE_OBJECT_BITS     0x0000ffff
 151
 152 /* status interrupt */
 153 #define STATUS_INTERRUPT        0x8000
 154
 155 /* global interrupt masks */
 156 #define ENABLE_ALL_INTERRUPTS   1
 157 #define DISABLE_ALL_INTERRUPTS  0
 158
 159 /* minimum timeout for checking BUSY status */
 160 #define MIN_TIMEOUT_VALUE       6
 161
 162 /* napi related */
 163 #define C_CAN_NAPI_WEIGHT       C_CAN_MSG_OBJ_RX_NUM
 164
 165 /* c_can lec values */
 166 enum c_can_lec_type {
 167         LEC_NO_ERROR = 0,
 168         LEC_STUFF_ERROR,
 169         LEC_FORM_ERROR,
 170         LEC_ACK_ERROR,
 171         LEC_BIT1_ERROR,
 172         LEC_BIT0_ERROR,
 173         LEC_CRC_ERROR,
 174         LEC_UNUSED,
 175 };
 176
 177 /*
 178  * c_can error types:
 179  * Bus errors (BUS_OFF, ERROR_WARNING, ERROR_PASSIVE) are supported
 180  */
 181 enum c_can_bus_error_types {
 182         C_CAN_NO_ERROR = 0,
 183         C_CAN_BUS_OFF,
 184         C_CAN_ERROR_WARNING,
 185         C_CAN_ERROR_PASSIVE,
 186 };
 187
 188 static struct can_bittiming_const c_can_bittiming_const = {
 189         .name = KBUILD_MODNAME,
 190         .tseg1_min = 2,         /* Time segment 1 = prop_seg + phase_seg1 */
 191         .tseg1_max = 16,
 192         .tseg2_min = 1,         /* Time segment 2 = phase_seg2 */
 193         .tseg2_max = 8,
 194         .sjw_max = 4,
 195         .brp_min = 1,
 196         .brp_max = 1024,        /* 6-bit BRP field + 4-bit BRPE field*/
 197         .brp_inc = 1,
 198 };
 199
 200 static inline int get_tx_next_msg_obj(const struct c_can_priv *priv)
 201 {
 202         return (priv->tx_next & C_CAN_NEXT_MSG_OBJ_MASK) +
 203                         C_CAN_MSG_OBJ_TX_FIRST;
 204 }
 205
 206 static inline int get_tx_echo_msg_obj(const struct c_can_priv *priv)
 207 {
 208         return (priv->tx_echo & C_CAN_NEXT_MSG_OBJ_MASK) +
 209                         C_CAN_MSG_OBJ_TX_FIRST;
 210 }
 211
 212 static u32 c_can_read_reg32(struct c_can_priv *priv, void *reg)
 213 {
 214         u32 val = priv->read_reg(priv, reg);
 215         val |= ((u32) priv->read_reg(priv, reg + 2)) << 16;
 216         return val;
 217 }
 218
 219 static void c_can_enable_all_interrupts(struct c_can_priv *priv,
 220                                                 int enable)
 221 {
 222         unsigned int cntrl_save = priv->read_reg(priv,
 223                                                 &priv->regs->control);
 224
 225         if (enable)
 226                 cntrl_save |= (CONTROL_SIE | CONTROL_EIE | CONTROL_IE);
 227         else
 228                 cntrl_save &= ~(CONTROL_EIE | CONTROL_IE | CONTROL_SIE);
 229
 230         priv->write_reg(priv, &priv->regs->control, cntrl_save);
 231 }
 232
 233 static inline int c_can_msg_obj_is_busy(struct c_can_priv *priv, int iface)
 234 {
 235         int count = MIN_TIMEOUT_VALUE;
 236
 237         while (count && priv->read_reg(priv,
 238                                 &priv->regs->ifregs[iface].com_req) &
 239                                 IF_COMR_BUSY) {
 240                 count--;
 241                 udelay(1);
 242         }
 243
 244         if (!count)
 245                 return 1;
 246
 247         return 0;
 248 }
 249
 250 static inline void c_can_object_get(struct net_device *dev,
 251                                         int iface, int objno, int mask)
 252 {
 253         struct c_can_priv *priv = netdev_priv(dev);
 254
 255         /*
 256          * As per specs, after writting the message object number in the
 257          * IF command request register the transfer b/w interface
 258          * register and message RAM must be complete in 6 CAN-CLK
 259          * period.
 260          */
 261         priv->write_reg(priv, &priv->regs->ifregs[iface].com_mask,
 262                         IFX_WRITE_LOW_16BIT(mask));
 263         priv->write_reg(priv, &priv->regs->ifregs[iface].com_req,
 264                         IFX_WRITE_LOW_16BIT(objno));
 265
 266         if (c_can_msg_obj_is_busy(priv, iface))
 267                 netdev_err(dev, "timed out in object get\n");
 268 }
 269
 270 static inline void c_can_object_put(struct net_device *dev,
 271                                         int iface, int objno, int mask)
 272 {
 273         struct c_can_priv *priv = netdev_priv(dev);
 274
 275         /*
 276          * As per specs, after writting the message object number in the
 277          * IF command request register the transfer b/w interface
 278          * register and message RAM must be complete in 6 CAN-CLK
 279          * period.
 280          */
 281         priv->write_reg(priv, &priv->regs->ifregs[iface].com_mask,
 282                         (IF_COMM_WR | IFX_WRITE_LOW_16BIT(mask)));
 283         priv->write_reg(priv, &priv->regs->ifregs[iface].com_req,
 284                         IFX_WRITE_LOW_16BIT(objno));
 285
 286         if (c_can_msg_obj_is_busy(priv, iface))
 287                 netdev_err(dev, "timed out in object put\n");
 288 }
 289
 290 static void c_can_write_msg_object(struct net_device *dev,
 291                         int iface, struct can_frame *frame, int objno)
 292 {
 293         int i;
 294         u16 flags = 0;
 295         unsigned int id;
 296         struct c_can_priv *priv = netdev_priv(dev);
 297
 298         if (!(frame->can_id & CAN_RTR_FLAG))
 299                 flags |= IF_ARB_TRANSMIT;
 300
 301         if (frame->can_id & CAN_EFF_FLAG) {
 302                 id = frame->can_id & CAN_EFF_MASK;
 303                 flags |= IF_ARB_MSGXTD;
 304         } else
 305                 id = ((frame->can_id & CAN_SFF_MASK) << 18);
 306
 307         flags |= IF_ARB_MSGVAL;
 308
 309         priv->write_reg(priv, &priv->regs->ifregs[iface].arb1,
 310                                 IFX_WRITE_LOW_16BIT(id));
 311         priv->write_reg(priv, &priv->regs->ifregs[iface].arb2, flags |
 312                                 IFX_WRITE_HIGH_16BIT(id));
 313
 314         for (i = 0; i < frame->can_dlc; i += 2) {
 315                 priv->write_reg(priv, &priv->regs->ifregs[iface].data[i / 2],
 316                                 frame->data[i] | (frame->data[i + 1] << 8));
 317         }
 318
 319         /* enable interrupt for this message object */
 320         priv->write_reg(priv, &priv->regs->ifregs[iface].msg_cntrl,
 321                         IF_MCONT_TXIE | IF_MCONT_TXRQST | IF_MCONT_EOB |
 322                         frame->can_dlc);
 323         c_can_object_put(dev, iface, objno, IF_COMM_ALL);
 324 }
 325
 326 static inline void c_can_mark_rx_msg_obj(struct net_device *dev,
 327                                                 int iface, int ctrl_mask,
 328                                                 int obj)
 329 {
 330         struct c_can_priv *priv = netdev_priv(dev);
 331
 332         priv->write_reg(priv, &priv->regs->ifregs[iface].msg_cntrl,
 333                         ctrl_mask & ~(IF_MCONT_MSGLST | IF_MCONT_INTPND));
 334         c_can_object_put(dev, iface, obj, IF_COMM_CONTROL);
 335
 336 }
 337
 338 static inline void c_can_activate_all_lower_rx_msg_obj(struct net_device *dev,
 339                                                 int iface,
 340                                                 int ctrl_mask)
 341 {
 342         int i;
 343         struct c_can_priv *priv = netdev_priv(dev);
 344
 345         for (i = C_CAN_MSG_OBJ_RX_FIRST; i <= C_CAN_MSG_RX_LOW_LAST; i++) {
 346                 priv->write_reg(priv, &priv->regs->ifregs[iface].msg_cntrl,
 347                                 ctrl_mask & ~(IF_MCONT_MSGLST |
 348                                         IF_MCONT_INTPND | IF_MCONT_NEWDAT));
 349                 c_can_object_put(dev, iface, i, IF_COMM_CONTROL);
 350         }
 351 }
 352
 353 static inline void c_can_activate_rx_msg_obj(struct net_device *dev,
 354                                                 int iface, int ctrl_mask,
 355                                                 int obj)
 356 {
 357         struct c_can_priv *priv = netdev_priv(dev);
 358
 359         priv->write_reg(priv, &priv->regs->ifregs[iface].msg_cntrl,
 360                         ctrl_mask & ~(IF_MCONT_MSGLST |
 361                                 IF_MCONT_INTPND | IF_MCONT_NEWDAT));
 362         c_can_object_put(dev, iface, obj, IF_COMM_CONTROL);
 363 }
 364
 365 static void c_can_handle_lost_msg_obj(struct net_device *dev,
 366                                         int iface, int objno)
 367 {
 368         struct c_can_priv *priv = netdev_priv(dev);
 369         struct net_device_stats *stats = &dev->stats;
 370         struct sk_buff *skb;
 371         struct can_frame *frame;
 372
 373         netdev_err(dev, "msg lost in buffer %d\n", objno);
 374
 375         c_can_object_get(dev, iface, objno, IF_COMM_ALL & ~IF_COMM_TXRQST);
 376
 377         priv->write_reg(priv, &priv->regs->ifregs[iface].msg_cntrl,
 378                         IF_MCONT_CLR_MSGLST);
 379
 380         c_can_object_put(dev, 0, objno, IF_COMM_CONTROL);
 381
 382         /* create an error msg */
 383         skb = alloc_can_err_skb(dev, &frame);
 384         if (unlikely(!skb))
 385                 return;
 386
 387         frame->can_id |= CAN_ERR_CRTL;
 388         frame->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
 389         stats->rx_errors++;
 390         stats->rx_over_errors++;
 391
 392         netif_receive_skb(skb);
 393 }
 394
 395 static int c_can_read_msg_object(struct net_device *dev, int iface, int ctrl)
 396 {
 397         u16 flags, data;
 398         int i;
 399         unsigned int val;
 400         struct c_can_priv *priv = netdev_priv(dev);
 401         struct net_device_stats *stats = &dev->stats;
 402         struct sk_buff *skb;
 403         struct can_frame *frame;
 404
 405         skb = alloc_can_skb(dev, &frame);
 406         if (!skb) {
 407                 stats->rx_dropped++;
 408                 return -ENOMEM;
 409         }
 410
 411         frame->can_dlc = get_can_dlc(ctrl & 0x0F);
 412
 413         flags = priv->read_reg(priv, &priv->regs->ifregs[iface].arb2);
 414         val = priv->read_reg(priv, &priv->regs->ifregs[iface].arb1) |
 415                 (flags << 16);
 416
 417         if (flags & IF_ARB_MSGXTD)
 418                 frame->can_id = (val & CAN_EFF_MASK) | CAN_EFF_FLAG;
 419         else
 420                 frame->can_id = (val >> 18) & CAN_SFF_MASK;
 421
 422         if (flags & IF_ARB_TRANSMIT)
 423                 frame->can_id |= CAN_RTR_FLAG;
 424         else {
 425                 for (i = 0; i < frame->can_dlc; i += 2) {
 426                         data = priv->read_reg(priv,
 427                                 &priv->regs->ifregs[iface].data[i / 2]);
 428                         frame->data[i] = data;
 429                         frame->data[i + 1] = data >> 8;
 430                 }
 431         }
 432
 433         netif_receive_skb(skb);
 434
 435         stats->rx_packets++;
 436         stats->rx_bytes += frame->can_dlc;
 437
 438         return 0;
 439 }
 440
 441 static void c_can_setup_receive_object(struct net_device *dev, int iface,
 442                                         int objno, unsigned int mask,
 443                                         unsigned int id, unsigned int mcont)
 444 {
 445         struct c_can_priv *priv = netdev_priv(dev);
 446
 447         priv->write_reg(priv, &priv->regs->ifregs[iface].mask1,
 448                         IFX_WRITE_LOW_16BIT(mask));
 449         priv->write_reg(priv, &priv->regs->ifregs[iface].mask2,
 450                         IFX_WRITE_HIGH_16BIT(mask));
 451
 452         priv->write_reg(priv, &priv->regs->ifregs[iface].arb1,
 453                         IFX_WRITE_LOW_16BIT(id));
 454         priv->write_reg(priv, &priv->regs->ifregs[iface].arb2,
 455                         (IF_ARB_MSGVAL | IFX_WRITE_HIGH_16BIT(id)));
 456
 457         priv->write_reg(priv, &priv->regs->ifregs[iface].msg_cntrl, mcont);
 458         c_can_object_put(dev, iface, objno, IF_COMM_ALL & ~IF_COMM_TXRQST);
 459
 460         netdev_dbg(dev, "obj no:%d, msgval:0x%08x\n", objno,
 461                         c_can_read_reg32(priv, &priv->regs->msgval1));
 462 }
 463
 464 static void c_can_inval_msg_object(struct net_device *dev, int iface, int objno)
 465 {
 466         struct c_can_priv *priv = netdev_priv(dev);
 467
 468         priv->write_reg(priv, &priv->regs->ifregs[iface].arb1, 0);
 469         priv->write_reg(priv, &priv->regs->ifregs[iface].arb2, 0);
 470         priv->write_reg(priv, &priv->regs->ifregs[iface].msg_cntrl, 0);
 471
 472         c_can_object_put(dev, iface, objno, IF_COMM_ARB | IF_COMM_CONTROL);
 473
 474         netdev_dbg(dev, "obj no:%d, msgval:0x%08x\n", objno,
 475                         c_can_read_reg32(priv, &priv->regs->msgval1));
 476 }
 477
 478 static inline int c_can_is_next_tx_obj_busy(struct c_can_priv *priv, int objno)
 479 {
 480         int val = c_can_read_reg32(priv, &priv->regs->txrqst1);
 481
 482         /*
 483          * as transmission request register's bit n-1 corresponds to
 484          * message object n, we need to handle the same properly.
 485          */
 486         if (val & (1 << (objno - 1)))
 487                 return 1;
 488
 489         return 0;
 490 }
 491
 492 static netdev_tx_t c_can_start_xmit(struct sk_buff *skb,
 493                                         struct net_device *dev)
 494 {
 495         u32 msg_obj_no;
 496         struct c_can_priv *priv = netdev_priv(dev);
 497         struct can_frame *frame = (struct can_frame *)skb->data;
 498
 499         if (can_dropped_invalid_skb(dev, skb))
 500                 return NETDEV_TX_OK;
 501
 502         msg_obj_no = get_tx_next_msg_obj(priv);
 503
 504         /* prepare message object for transmission */
 505         c_can_write_msg_object(dev, 0, frame, msg_obj_no);
 506         can_put_echo_skb(skb, dev, msg_obj_no - C_CAN_MSG_OBJ_TX_FIRST);
 507
 508         /*
 509          * we have to stop the queue in case of a wrap around or
 510          * if the next TX message object is still in use
 511          */
 512         priv->tx_next++;
 513         if (c_can_is_next_tx_obj_busy(priv, get_tx_next_msg_obj(priv)) ||
 514                         (priv->tx_next & C_CAN_NEXT_MSG_OBJ_MASK) == 0)
 515                 netif_stop_queue(dev);
 516
 517         return NETDEV_TX_OK;
 518 }
 519
 520 static int c_can_set_bittiming(struct net_device *dev)
 521 {
 522         unsigned int reg_btr, reg_brpe, ctrl_save;
 523         u8 brp, brpe, sjw, tseg1, tseg2;
 524         u32 ten_bit_brp;
 525         struct c_can_priv *priv = netdev_priv(dev);
 526         const struct can_bittiming *bt = &priv->can.bittiming;
 527
 528         /* c_can provides a 6-bit brp and 4-bit brpe fields */
 529         ten_bit_brp = bt->brp - 1;
 530         brp = ten_bit_brp & BTR_BRP_MASK;
 531         brpe = ten_bit_brp >> 6;
 532
 533         sjw = bt->sjw - 1;
 534         tseg1 = bt->prop_seg + bt->phase_seg1 - 1;
 535         tseg2 = bt->phase_seg2 - 1;
 536         reg_btr = brp | (sjw << BTR_SJW_SHIFT) | (tseg1 << BTR_TSEG1_SHIFT) |
 537                         (tseg2 << BTR_TSEG2_SHIFT);
 538         reg_brpe = brpe & BRP_EXT_BRPE_MASK;
 539
 540         netdev_info(dev,
 541                 "setting BTR=%04x BRPE=%04x\n", reg_btr, reg_brpe);
 542
 543         ctrl_save = priv->read_reg(priv, &priv->regs->control);
 544         priv->write_reg(priv, &priv->regs->control,
 545                         ctrl_save | CONTROL_CCE | CONTROL_INIT);
 546         priv->write_reg(priv, &priv->regs->btr, reg_btr);
 547         priv->write_reg(priv, &priv->regs->brp_ext, reg_brpe);
 548         priv->write_reg(priv, &priv->regs->control, ctrl_save);
 549
 550         return 0;
 551 }
 552
 553 /*
 554  * Configure C_CAN message objects for Tx and Rx purposes:
 555  * C_CAN provides a total of 32 message objects that can be configured
 556  * either for Tx or Rx purposes. Here the first 16 message objects are used as
 557  * a reception FIFO. The end of reception FIFO is signified by the EoB bit
 558  * being SET. The remaining 16 message objects are kept aside for Tx purposes.
 559  * See user guide document for further details on configuring message
 560  * objects.
 561  */
 562 static void c_can_configure_msg_objects(struct net_device *dev)
 563 {
 564         int i;
 565
 566         /* first invalidate all message objects */
 567         for (i = C_CAN_MSG_OBJ_RX_FIRST; i <= C_CAN_NO_OF_OBJECTS; i++)
 568                 c_can_inval_msg_object(dev, 0, i);
 569
 570         /* setup receive message objects */
 571         for (i = C_CAN_MSG_OBJ_RX_FIRST; i < C_CAN_MSG_OBJ_RX_LAST; i++)
 572                 c_can_setup_receive_object(dev, 0, i, 0, 0,
 573                         (IF_MCONT_RXIE | IF_MCONT_UMASK) & ~IF_MCONT_EOB);
 574
 575         c_can_setup_receive_object(dev, 0, C_CAN_MSG_OBJ_RX_LAST, 0, 0,
 576                         IF_MCONT_EOB | IF_MCONT_RXIE | IF_MCONT_UMASK);
 577 }
 578
 579 /*
 580  * Configure C_CAN chip:
 581  * - enable/disable auto-retransmission
 582  * - set operating mode
 583  * - configure message objects
 584  */
 585 static void c_can_chip_config(struct net_device *dev)
 586 {
 587         struct c_can_priv *priv = netdev_priv(dev);
 588
 589         /* enable automatic retransmission */
 590         priv->write_reg(priv, &priv->regs->control,
 591                         CONTROL_ENABLE_AR);
 592
 593         if (priv->can.ctrlmode & (CAN_CTRLMODE_LISTENONLY &
 594                                         CAN_CTRLMODE_LOOPBACK)) {
 595                 /* loopback + silent mode : useful for hot self-test */
 596                 priv->write_reg(priv, &priv->regs->control, CONTROL_EIE |
 597                                 CONTROL_SIE | CONTROL_IE | CONTROL_TEST);
 598                 priv->write_reg(priv, &priv->regs->test,
 599                                 TEST_LBACK | TEST_SILENT);
 600         } else if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK) {
 601                 /* loopback mode : useful for self-test function */
 602                 priv->write_reg(priv, &priv->regs->control, CONTROL_EIE |
 603                                 CONTROL_SIE | CONTROL_IE | CONTROL_TEST);
 604                 priv->write_reg(priv, &priv->regs->test, TEST_LBACK);
 605         } else if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY) {
 606                 /* silent mode : bus-monitoring mode */
 607                 priv->write_reg(priv, &priv->regs->control, CONTROL_EIE |
 608                                 CONTROL_SIE | CONTROL_IE | CONTROL_TEST);
 609                 priv->write_reg(priv, &priv->regs->test, TEST_SILENT);
 610         } else
 611                 /* normal mode*/
 612                 priv->write_reg(priv, &priv->regs->control,
 613                                 CONTROL_EIE | CONTROL_SIE | CONTROL_IE);
 614
 615         /* configure message objects */
 616         c_can_configure_msg_objects(dev);
 617
 618         /* set a `lec` value so that we can check for updates later */
 619         priv->write_reg(priv, &priv->regs->status, LEC_UNUSED);
 620
 621         /* set bittiming params */
 622         c_can_set_bittiming(dev);
 623 }
 624
 625 static void c_can_start(struct net_device *dev)
 626 {
 627         struct c_can_priv *priv = netdev_priv(dev);
 628
 629         /* basic c_can configuration */
 630         c_can_chip_config(dev);
 631
 632         priv->can.state = CAN_STATE_ERROR_ACTIVE;
 633
 634         /* reset tx helper pointers */
 635         priv->tx_next = priv->tx_echo = 0;
 636
 637         /* enable status change, error and module interrupts */
 638         c_can_enable_all_interrupts(priv, ENABLE_ALL_INTERRUPTS);
 639 }
 640
 641 static void c_can_stop(struct net_device *dev)
 642 {
 643         struct c_can_priv *priv = netdev_priv(dev);
 644
 645         /* disable all interrupts */
 646         c_can_enable_all_interrupts(priv, DISABLE_ALL_INTERRUPTS);
 647
 648         /* set the state as STOPPED */
 649         priv->can.state = CAN_STATE_STOPPED;
 650 }
 651
 652 static int c_can_set_mode(struct net_device *dev, enum can_mode mode)
 653 {
 654         switch (mode) {
 655         case CAN_MODE_START:
 656                 c_can_start(dev);
 657                 netif_wake_queue(dev);
 658                 break;
 659         default:
 660                 return -EOPNOTSUPP;
 661         }
 662
 663         return 0;
 664 }
 665
 666 static int c_can_get_berr_counter(const struct net_device *dev,
 667                                         struct can_berr_counter *bec)
 668 {
 669         unsigned int reg_err_counter;
 670         struct c_can_priv *priv = netdev_priv(dev);
 671
 672         reg_err_counter = priv->read_reg(priv, &priv->regs->err_cnt);
 673         bec->rxerr = (reg_err_counter & ERR_CNT_REC_MASK) >>
 674                                 ERR_CNT_REC_SHIFT;
 675         bec->txerr = reg_err_counter & ERR_CNT_TEC_MASK;
 676
 677         return 0;
 678 }
 679
 680 /*
 681  * theory of operation:
 682  *
 683  * priv->tx_echo holds the number of the oldest can_frame put for
 684  * transmission into the hardware, but not yet ACKed by the CAN tx
 685  * complete IRQ.
 686  *
 687  * We iterate from priv->tx_echo to priv->tx_next and check if the
 688  * packet has been transmitted, echo it back to the CAN framework.
 689  * If we discover a not yet transmitted packet, stop looking for more.
 690  */
 691 static void c_can_do_tx(struct net_device *dev)
 692 {
 693         u32 val;
 694         u32 msg_obj_no;
 695         struct c_can_priv *priv = netdev_priv(dev);
 696         struct net_device_stats *stats = &dev->stats;
 697
 698         for (/* nix */; (priv->tx_next - priv->tx_echo) > 0; priv->tx_echo++) {
 699                 msg_obj_no = get_tx_echo_msg_obj(priv);
 700                 val = c_can_read_reg32(priv, &priv->regs->txrqst1);
 701                 if (!(val & (1 << (msg_obj_no - 1)))) {
 702                         can_get_echo_skb(dev,
 703                                         msg_obj_no - C_CAN_MSG_OBJ_TX_FIRST);
 704                         stats->tx_bytes += priv->read_reg(priv,
 705                                         &priv->regs->ifregs[0].msg_cntrl)
 706                                         & IF_MCONT_DLC_MASK;
 707                         stats->tx_packets++;
 708                         c_can_inval_msg_object(dev, 0, msg_obj_no);
 709                 } else {
 710                         break;
 711                 }
 712         }
 713
 714         /* restart queue if wrap-up or if queue stalled on last pkt */
 715         if (((priv->tx_next & C_CAN_NEXT_MSG_OBJ_MASK) != 0) ||
 716                         ((priv->tx_echo & C_CAN_NEXT_MSG_OBJ_MASK) == 0))
 717                 netif_wake_queue(dev);
 718 }
 719
 720 /*
 721  * theory of operation:
 722  *
 723  * c_can core saves a received CAN message into the first free message
 724  * object it finds free (starting with the lowest). Bits NEWDAT and
 725  * INTPND are set for this message object indicating that a new message
 726  * has arrived. To work-around this issue, we keep two groups of message
 727  * objects whose partitioning is defined by C_CAN_MSG_OBJ_RX_SPLIT.
 728  *
 729  * To ensure in-order frame reception we use the following
 730  * approach while re-activating a message object to receive further
 731  * frames:
 732  * - if the current message object number is lower than
 733  *   C_CAN_MSG_RX_LOW_LAST, do not clear the NEWDAT bit while clearing
 734  *   the INTPND bit.
 735  * - if the current message object number is equal to
 736  *   C_CAN_MSG_RX_LOW_LAST then clear the NEWDAT bit of all lower
 737  *   receive message objects.
 738  * - if the current message object number is greater than
 739  *   C_CAN_MSG_RX_LOW_LAST then clear the NEWDAT bit of
 740  *   only this message object.
 741  */
 742 static int c_can_do_rx_poll(struct net_device *dev, int quota)
 743 {
 744         u32 num_rx_pkts = 0;
 745         unsigned int msg_obj, msg_ctrl_save;
 746         struct c_can_priv *priv = netdev_priv(dev);
 747         u32 val = c_can_read_reg32(priv, &priv->regs->intpnd1);
 748
 749         for (msg_obj = C_CAN_MSG_OBJ_RX_FIRST;
 750                         msg_obj <= C_CAN_MSG_OBJ_RX_LAST && quota > 0;
 751                         val = c_can_read_reg32(priv, &priv->regs->intpnd1),
 752                         msg_obj++) {
 753                 /*
 754                  * as interrupt pending register's bit n-1 corresponds to
 755                  * message object n, we need to handle the same properly.
 756                  */
 757                 if (val & (1 << (msg_obj - 1))) {
 758                         c_can_object_get(dev, 0, msg_obj, IF_COMM_ALL &
 759                                         ~IF_COMM_TXRQST);
 760                         msg_ctrl_save = priv->read_reg(priv,
 761                                         &priv->regs->ifregs[0].msg_cntrl);
 762
 763                         if (msg_ctrl_save & IF_MCONT_EOB)
 764                                 return num_rx_pkts;
 765
 766                         if (msg_ctrl_save & IF_MCONT_MSGLST) {
 767                                 c_can_handle_lost_msg_obj(dev, 0, msg_obj);
 768                                 num_rx_pkts++;
 769                                 quota--;
 770                                 continue;
 771                         }
 772
 773                         if (!(msg_ctrl_save & IF_MCONT_NEWDAT))
 774                                 continue;
 775
 776                         /* read the data from the message object */
 777                         c_can_read_msg_object(dev, 0, msg_ctrl_save);
 778
 779                         if (msg_obj < C_CAN_MSG_RX_LOW_LAST)
 780                                 c_can_mark_rx_msg_obj(dev, 0,
 781                                                 msg_ctrl_save, msg_obj);
 782                         else if (msg_obj > C_CAN_MSG_RX_LOW_LAST)
 783                                 /* activate this msg obj */
 784                                 c_can_activate_rx_msg_obj(dev, 0,
 785                                                 msg_ctrl_save, msg_obj);
 786                         else if (msg_obj == C_CAN_MSG_RX_LOW_LAST)
 787                                 /* activate all lower message objects */
 788                                 c_can_activate_all_lower_rx_msg_obj(dev,
 789                                                 0, msg_ctrl_save);
 790
 791                         num_rx_pkts++;
 792                         quota--;
 793                 }
 794         }
 795
 796         return num_rx_pkts;
 797 }
 798
 799 static inline int c_can_has_and_handle_berr(struct c_can_priv *priv)
 800 {
 801         return (priv->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING) &&
 802                 (priv->current_status & LEC_UNUSED);
 803 }
 804
 805 static int c_can_handle_state_change(struct net_device *dev,
 806                                 enum c_can_bus_error_types error_type)
 807 {
 808         unsigned int reg_err_counter;
 809         unsigned int rx_err_passive;
 810         struct c_can_priv *priv = netdev_priv(dev);
 811         struct net_device_stats *stats = &dev->stats;
 812         struct can_frame *cf;
 813         struct sk_buff *skb;
 814         struct can_berr_counter bec;
 815
 816         /* propagate the error condition to the CAN stack */
 817         skb = alloc_can_err_skb(dev, &cf);
 818         if (unlikely(!skb))
 819                 return 0;
 820
 821         c_can_get_berr_counter(dev, &bec);
 822         reg_err_counter = priv->read_reg(priv, &priv->regs->err_cnt);
 823         rx_err_passive = (reg_err_counter & ERR_CNT_RP_MASK) >>
 824                                 ERR_CNT_RP_SHIFT;
 825
 826         switch (error_type) {
 827         case C_CAN_ERROR_WARNING:
 828                 /* error warning state */
 829                 priv->can.can_stats.error_warning++;
 830                 priv->can.state = CAN_STATE_ERROR_WARNING;
 831                 cf->can_id |= CAN_ERR_CRTL;
 832                 cf->data[1] = (bec.txerr > bec.rxerr) ?
 833                         CAN_ERR_CRTL_TX_WARNING :
 834                         CAN_ERR_CRTL_RX_WARNING;
 835                 cf->data[6] = bec.txerr;
 836                 cf->data[7] = bec.rxerr;
 837
 838                 break;
 839         case C_CAN_ERROR_PASSIVE:
 840                 /* error passive state */
 841                 priv->can.can_stats.error_passive++;
 842                 priv->can.state = CAN_STATE_ERROR_PASSIVE;
 843                 cf->can_id |= CAN_ERR_CRTL;
 844                 if (rx_err_passive)
 845                         cf->data[1] |= CAN_ERR_CRTL_RX_PASSIVE;
 846                 if (bec.txerr > 127)
 847                         cf->data[1] |= CAN_ERR_CRTL_TX_PASSIVE;
 848
 849                 cf->data[6] = bec.txerr;
 850                 cf->data[7] = bec.rxerr;
 851                 break;
 852         case C_CAN_BUS_OFF:
 853                 /* bus-off state */
 854                 priv->can.state = CAN_STATE_BUS_OFF;
 855                 cf->can_id |= CAN_ERR_BUSOFF;
 856                 /*
 857                  * disable all interrupts in bus-off mode to ensure that
 858                  * the CPU is not hogged down
 859                  */
 860                 c_can_enable_all_interrupts(priv, DISABLE_ALL_INTERRUPTS);
 861                 can_bus_off(dev);
 862                 break;
 863         default:
 864                 break;
 865         }
 866
 867         netif_receive_skb(skb);
 868         stats->rx_packets++;
 869         stats->rx_bytes += cf->can_dlc;
 870
 871         return 1;
 872 }
 873
 874 static int c_can_handle_bus_err(struct net_device *dev,
 875                                 enum c_can_lec_type lec_type)
 876 {
 877         struct c_can_priv *priv = netdev_priv(dev);
 878         struct net_device_stats *stats = &dev->stats;
 879         struct can_frame *cf;
 880         struct sk_buff *skb;
 881
 882         /*
 883          * early exit if no lec update or no error.
 884          * no lec update means that no CAN bus event has been detected
 885          * since CPU wrote 0x7 value to status reg.
 886          */
 887         if (lec_type == LEC_UNUSED || lec_type == LEC_NO_ERROR)
 888                 return 0;
 889
 890         /* propagate the error condition to the CAN stack */
 891         skb = alloc_can_err_skb(dev, &cf);
 892         if (unlikely(!skb))
 893                 return 0;
 894
 895         /*
 896          * check for 'last error code' which tells us the
 897          * type of the last error to occur on the CAN bus
 898          */
 899
 900         /* common for all type of bus errors */
 901         priv->can.can_stats.bus_error++;
 902         stats->rx_errors++;
 903         cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
 904         cf->data[2] |= CAN_ERR_PROT_UNSPEC;
 905
 906         switch (lec_type) {
 907         case LEC_STUFF_ERROR:
 908                 netdev_dbg(dev, "stuff error\n");
 909                 cf->data[2] |= CAN_ERR_PROT_STUFF;
 910                 break;
 911         case LEC_FORM_ERROR:
 912                 netdev_dbg(dev, "form error\n");
 913                 cf->data[2] |= CAN_ERR_PROT_FORM;
 914                 break;
 915         case LEC_ACK_ERROR:
 916                 netdev_dbg(dev, "ack error\n");
 917                 cf->data[2] |= (CAN_ERR_PROT_LOC_ACK |
 918                                 CAN_ERR_PROT_LOC_ACK_DEL);
 919                 break;
 920         case LEC_BIT1_ERROR:
 921                 netdev_dbg(dev, "bit1 error\n");
 922                 cf->data[2] |= CAN_ERR_PROT_BIT1;
 923                 break;
 924         case LEC_BIT0_ERROR:
 925                 netdev_dbg(dev, "bit0 error\n");
 926                 cf->data[2] |= CAN_ERR_PROT_BIT0;
 927                 break;
 928         case LEC_CRC_ERROR:
 929                 netdev_dbg(dev, "CRC error\n");
 930                 cf->data[2] |= (CAN_ERR_PROT_LOC_CRC_SEQ |
 931                                 CAN_ERR_PROT_LOC_CRC_DEL);
 932                 break;
 933         default:
 934                 break;
 935         }
 936
 937         /* set a `lec` value so that we can check for updates later */
 938         priv->write_reg(priv, &priv->regs->status, LEC_UNUSED);
 939
 940         netif_receive_skb(skb);
 941         stats->rx_packets++;
 942         stats->rx_bytes += cf->can_dlc;
 943
 944         return 1;
 945 }
 946
 947 static int c_can_poll(struct napi_struct *napi, int quota)
 948 {
 949         u16 irqstatus;
 950         int lec_type = 0;
 951         int work_done = 0;
 952         struct net_device *dev = napi->dev;
 953         struct c_can_priv *priv = netdev_priv(dev);
 954
 955         irqstatus = priv->irqstatus;
 956         if (!irqstatus)
 957                 goto end;
 958
 959         /* status events have the highest priority */
 960         if (irqstatus == STATUS_INTERRUPT) {
 961                 priv->current_status = priv->read_reg(priv,
 962                                         &priv->regs->status);
 963
 964                 /* handle Tx/Rx events */
 965                 if (priv->current_status & STATUS_TXOK)
 966                         priv->write_reg(priv, &priv->regs->status,
 967                                         priv->current_status & ~STATUS_TXOK);
 968
 969                 if (priv->current_status & STATUS_RXOK)
 970                         priv->write_reg(priv, &priv->regs->status,
 971                                         priv->current_status & ~STATUS_RXOK);
 972
 973                 /* handle state changes */
 974                 if ((priv->current_status & STATUS_EWARN) &&
 975                                 (!(priv->last_status & STATUS_EWARN))) {
 976                         netdev_dbg(dev, "entered error warning state\n");
 977                         work_done += c_can_handle_state_change(dev,
 978                                                 C_CAN_ERROR_WARNING);
 979                 }
 980                 if ((priv->current_status & STATUS_EPASS) &&
 981                                 (!(priv->last_status & STATUS_EPASS))) {
 982                         netdev_dbg(dev, "entered error passive state\n");
 983                         work_done += c_can_handle_state_change(dev,
 984                                                 C_CAN_ERROR_PASSIVE);
 985                 }
 986                 if ((priv->current_status & STATUS_BOFF) &&
 987                                 (!(priv->last_status & STATUS_BOFF))) {
 988                         netdev_dbg(dev, "entered bus off state\n");
 989                         work_done += c_can_handle_state_change(dev,
 990                                                 C_CAN_BUS_OFF);
 991                 }
 992
 993                 /* handle bus recovery events */
 994                 if ((!(priv->current_status & STATUS_BOFF)) &&
 995                                 (priv->last_status & STATUS_BOFF)) {
 996                         netdev_dbg(dev, "left bus off state\n");
 997                         priv->can.state = CAN_STATE_ERROR_ACTIVE;
 998                 }
 999                 if ((!(priv->current_status & STATUS_EPASS)) &&
1000                                 (priv->last_status & STATUS_EPASS)) {
1001                         netdev_dbg(dev, "left error passive state\n");
1002                         priv->can.state = CAN_STATE_ERROR_ACTIVE;
1003                 }
1004
1005                 priv->last_status = priv->current_status;
1006
1007                 /* handle lec errors on the bus */
1008                 lec_type = c_can_has_and_handle_berr(priv);
1009                 if (lec_type)
1010                         work_done += c_can_handle_bus_err(dev, lec_type);
1011         } else if ((irqstatus >= C_CAN_MSG_OBJ_RX_FIRST) &&
1012                         (irqstatus <= C_CAN_MSG_OBJ_RX_LAST)) {
1013                 /* handle events corresponding to receive message objects */
1014                 work_done += c_can_do_rx_poll(dev, (quota - work_done));
1015         } else if ((irqstatus >= C_CAN_MSG_OBJ_TX_FIRST) &&
1016                         (irqstatus <= C_CAN_MSG_OBJ_TX_LAST)) {
1017                 /* handle events corresponding to transmit message objects */
1018                 c_can_do_tx(dev);
1019         }
1020
1021 end:
1022         if (work_done < quota) {
1023                 napi_complete(napi);
1024                 /* enable all IRQs */
1025                 c_can_enable_all_interrupts(priv, ENABLE_ALL_INTERRUPTS);
1026         }
1027
1028         return work_done;
1029 }
1030
1031 static irqreturn_t c_can_isr(int irq, void *dev_id)
1032 {
1033         struct net_device *dev = (struct net_device *)dev_id;
1034         struct c_can_priv *priv = netdev_priv(dev);
1035
1036         priv->irqstatus = priv->read_reg(priv, &priv->regs->interrupt);
1037         if (!priv->irqstatus)
1038                 return IRQ_NONE;
1039
1040         /* disable all interrupts and schedule the NAPI */
1041         c_can_enable_all_interrupts(priv, DISABLE_ALL_INTERRUPTS);
1042         napi_schedule(&priv->napi);
1043
1044         return IRQ_HANDLED;
1045 }
1046
1047 static int c_can_open(struct net_device *dev)
1048 {
1049         int err;
1050         struct c_can_priv *priv = netdev_priv(dev);
1051
1052         /* open the can device */
1053         err = open_candev(dev);
1054         if (err) {
1055                 netdev_err(dev, "failed to open can device\n");
1056                 return err;
1057         }
1058
1059         /* register interrupt handler */
1060         err = request_irq(dev->irq, &c_can_isr, IRQF_SHARED, dev->name,
1061                                 dev);
1062         if (err < 0) {
1063                 netdev_err(dev, "failed to request interrupt\n");
1064                 goto exit_irq_fail;
1065         }
1066
1067         napi_enable(&priv->napi);
1068
1069         /* start the c_can controller */
1070         c_can_start(dev);
1071
1072         netif_start_queue(dev);
1073
1074         return 0;
1075
1076 exit_irq_fail:
1077         close_candev(dev);
1078         return err;
1079 }
1080
1081 static int c_can_close(struct net_device *dev)
1082 {
1083         struct c_can_priv *priv = netdev_priv(dev);
1084
1085         netif_stop_queue(dev);
1086         napi_disable(&priv->napi);
1087         c_can_stop(dev);
1088         free_irq(dev->irq, dev);
1089         close_candev(dev);
1090
1091         return 0;
1092 }
1093
1094 struct net_device *alloc_c_can_dev(void)
1095 {
1096         struct net_device *dev;
1097         struct c_can_priv *priv;
1098
1099         dev = alloc_candev(sizeof(struct c_can_priv), C_CAN_MSG_OBJ_TX_NUM);
1100         if (!dev)
1101                 return NULL;
1102
1103         priv = netdev_priv(dev);
1104         netif_napi_add(dev, &priv->napi, c_can_poll, C_CAN_NAPI_WEIGHT);
1105
1106         priv->dev = dev;
1107         priv->can.bittiming_const = &c_can_bittiming_const;
1108         priv->can.do_set_mode = c_can_set_mode;
1109         priv->can.do_get_berr_counter = c_can_get_berr_counter;
1110         priv->can.ctrlmode_supported = CAN_CTRLMODE_LOOPBACK |
1111                                         CAN_CTRLMODE_LISTENONLY |
1112                                         CAN_CTRLMODE_BERR_REPORTING;
1113
1114         return dev;
1115 }
1116 EXPORT_SYMBOL_GPL(alloc_c_can_dev);
1117
1118 void free_c_can_dev(struct net_device *dev)
1119 {
1120         free_candev(dev);
1121 }
1122 EXPORT_SYMBOL_GPL(free_c_can_dev);
1123
1124 static const struct net_device_ops c_can_netdev_ops = {
1125         .ndo_open = c_can_open,
1126         .ndo_stop = c_can_close,
1127         .ndo_start_xmit = c_can_start_xmit,
1128 };
1129
1130 int register_c_can_dev(struct net_device *dev)
1131 {
1132         dev->flags |= IFF_ECHO; /* we support local echo */
1133         dev->netdev_ops = &c_can_netdev_ops;
1134
1135         return register_candev(dev);
1136 }
1137 EXPORT_SYMBOL_GPL(register_c_can_dev);
1138
1139 void unregister_c_can_dev(struct net_device *dev)
1140 {
1141         struct c_can_priv *priv = netdev_priv(dev);
1142
1143         /* disable all interrupts */
1144         c_can_enable_all_interrupts(priv, DISABLE_ALL_INTERRUPTS);
1145
1146         unregister_candev(dev);
1147 }
1148 EXPORT_SYMBOL_GPL(unregister_c_can_dev);
1149
1150 MODULE_AUTHOR("Bhupesh Sharma <bhupesh.sharma@st.com>");
1151 MODULE_LICENSE("GPL v2");
1152 MODULE_DESCRIPTION("CAN bus driver for Bosch C_CAN controller");