linux/drivers/net/can/rcar_can.c
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   1/* Renesas R-Car CAN device driver
   2 *
   3 * Copyright (C) 2013 Cogent Embedded, Inc. <source@cogentembedded.com>
   4 * Copyright (C) 2013 Renesas Solutions Corp.
   5 *
   6 * This program is free software; you can redistribute  it and/or modify it
   7 * under  the terms of  the GNU General  Public License as published by the
   8 * Free Software Foundation;  either version 2 of the  License, or (at your
   9 * option) any later version.
  10 */
  11
  12#include <linux/module.h>
  13#include <linux/kernel.h>
  14#include <linux/types.h>
  15#include <linux/interrupt.h>
  16#include <linux/errno.h>
  17#include <linux/netdevice.h>
  18#include <linux/platform_device.h>
  19#include <linux/can/led.h>
  20#include <linux/can/dev.h>
  21#include <linux/clk.h>
  22#include <linux/can/platform/rcar_can.h>
  23#include <linux/of.h>
  24
  25#define RCAR_CAN_DRV_NAME       "rcar_can"
  26
  27/* Mailbox configuration:
  28 * mailbox 60 - 63 - Rx FIFO mailboxes
  29 * mailbox 56 - 59 - Tx FIFO mailboxes
  30 * non-FIFO mailboxes are not used
  31 */
  32#define RCAR_CAN_N_MBX          64 /* Number of mailboxes in non-FIFO mode */
  33#define RCAR_CAN_RX_FIFO_MBX    60 /* Mailbox - window to Rx FIFO */
  34#define RCAR_CAN_TX_FIFO_MBX    56 /* Mailbox - window to Tx FIFO */
  35#define RCAR_CAN_FIFO_DEPTH     4
  36
  37/* Mailbox registers structure */
  38struct rcar_can_mbox_regs {
  39        u32 id;         /* IDE and RTR bits, SID and EID */
  40        u8 stub;        /* Not used */
  41        u8 dlc;         /* Data Length Code - bits [0..3] */
  42        u8 data[8];     /* Data Bytes */
  43        u8 tsh;         /* Time Stamp Higher Byte */
  44        u8 tsl;         /* Time Stamp Lower Byte */
  45};
  46
  47struct rcar_can_regs {
  48        struct rcar_can_mbox_regs mb[RCAR_CAN_N_MBX]; /* Mailbox registers */
  49        u32 mkr_2_9[8]; /* Mask Registers 2-9 */
  50        u32 fidcr[2];   /* FIFO Received ID Compare Register */
  51        u32 mkivlr1;    /* Mask Invalid Register 1 */
  52        u32 mier1;      /* Mailbox Interrupt Enable Register 1 */
  53        u32 mkr_0_1[2]; /* Mask Registers 0-1 */
  54        u32 mkivlr0;    /* Mask Invalid Register 0*/
  55        u32 mier0;      /* Mailbox Interrupt Enable Register 0 */
  56        u8 pad_440[0x3c0];
  57        u8 mctl[64];    /* Message Control Registers */
  58        u16 ctlr;       /* Control Register */
  59        u16 str;        /* Status register */
  60        u8 bcr[3];      /* Bit Configuration Register */
  61        u8 clkr;        /* Clock Select Register */
  62        u8 rfcr;        /* Receive FIFO Control Register */
  63        u8 rfpcr;       /* Receive FIFO Pointer Control Register */
  64        u8 tfcr;        /* Transmit FIFO Control Register */
  65        u8 tfpcr;       /* Transmit FIFO Pointer Control Register */
  66        u8 eier;        /* Error Interrupt Enable Register */
  67        u8 eifr;        /* Error Interrupt Factor Judge Register */
  68        u8 recr;        /* Receive Error Count Register */
  69        u8 tecr;        /* Transmit Error Count Register */
  70        u8 ecsr;        /* Error Code Store Register */
  71        u8 cssr;        /* Channel Search Support Register */
  72        u8 mssr;        /* Mailbox Search Status Register */
  73        u8 msmr;        /* Mailbox Search Mode Register */
  74        u16 tsr;        /* Time Stamp Register */
  75        u8 afsr;        /* Acceptance Filter Support Register */
  76        u8 pad_857;
  77        u8 tcr;         /* Test Control Register */
  78        u8 pad_859[7];
  79        u8 ier;         /* Interrupt Enable Register */
  80        u8 isr;         /* Interrupt Status Register */
  81        u8 pad_862;
  82        u8 mbsmr;       /* Mailbox Search Mask Register */
  83};
  84
  85struct rcar_can_priv {
  86        struct can_priv can;    /* Must be the first member! */
  87        struct net_device *ndev;
  88        struct napi_struct napi;
  89        struct rcar_can_regs __iomem *regs;
  90        struct clk *clk;
  91        struct clk *can_clk;
  92        u8 tx_dlc[RCAR_CAN_FIFO_DEPTH];
  93        u32 tx_head;
  94        u32 tx_tail;
  95        u8 clock_select;
  96        u8 ier;
  97};
  98
  99static const struct can_bittiming_const rcar_can_bittiming_const = {
 100        .name = RCAR_CAN_DRV_NAME,
 101        .tseg1_min = 4,
 102        .tseg1_max = 16,
 103        .tseg2_min = 2,
 104        .tseg2_max = 8,
 105        .sjw_max = 4,
 106        .brp_min = 1,
 107        .brp_max = 1024,
 108        .brp_inc = 1,
 109};
 110
 111/* Control Register bits */
 112#define RCAR_CAN_CTLR_BOM       (3 << 11) /* Bus-Off Recovery Mode Bits */
 113#define RCAR_CAN_CTLR_BOM_ENT   (1 << 11) /* Entry to halt mode */
 114                                        /* at bus-off entry */
 115#define RCAR_CAN_CTLR_SLPM      (1 << 10)
 116#define RCAR_CAN_CTLR_CANM      (3 << 8) /* Operating Mode Select Bit */
 117#define RCAR_CAN_CTLR_CANM_HALT (1 << 9)
 118#define RCAR_CAN_CTLR_CANM_RESET (1 << 8)
 119#define RCAR_CAN_CTLR_CANM_FORCE_RESET (3 << 8)
 120#define RCAR_CAN_CTLR_MLM       (1 << 3) /* Message Lost Mode Select */
 121#define RCAR_CAN_CTLR_IDFM      (3 << 1) /* ID Format Mode Select Bits */
 122#define RCAR_CAN_CTLR_IDFM_MIXED (1 << 2) /* Mixed ID mode */
 123#define RCAR_CAN_CTLR_MBM       (1 << 0) /* Mailbox Mode select */
 124
 125/* Status Register bits */
 126#define RCAR_CAN_STR_RSTST      (1 << 8) /* Reset Status Bit */
 127
 128/* FIFO Received ID Compare Registers 0 and 1 bits */
 129#define RCAR_CAN_FIDCR_IDE      (1 << 31) /* ID Extension Bit */
 130#define RCAR_CAN_FIDCR_RTR      (1 << 30) /* Remote Transmission Request Bit */
 131
 132/* Receive FIFO Control Register bits */
 133#define RCAR_CAN_RFCR_RFEST     (1 << 7) /* Receive FIFO Empty Status Flag */
 134#define RCAR_CAN_RFCR_RFE       (1 << 0) /* Receive FIFO Enable */
 135
 136/* Transmit FIFO Control Register bits */
 137#define RCAR_CAN_TFCR_TFUST     (7 << 1) /* Transmit FIFO Unsent Message */
 138                                        /* Number Status Bits */
 139#define RCAR_CAN_TFCR_TFUST_SHIFT 1     /* Offset of Transmit FIFO Unsent */
 140                                        /* Message Number Status Bits */
 141#define RCAR_CAN_TFCR_TFE       (1 << 0) /* Transmit FIFO Enable */
 142
 143#define RCAR_CAN_N_RX_MKREGS1   2       /* Number of mask registers */
 144                                        /* for Rx mailboxes 0-31 */
 145#define RCAR_CAN_N_RX_MKREGS2   8
 146
 147/* Bit Configuration Register settings */
 148#define RCAR_CAN_BCR_TSEG1(x)   (((x) & 0x0f) << 20)
 149#define RCAR_CAN_BCR_BPR(x)     (((x) & 0x3ff) << 8)
 150#define RCAR_CAN_BCR_SJW(x)     (((x) & 0x3) << 4)
 151#define RCAR_CAN_BCR_TSEG2(x)   ((x) & 0x07)
 152
 153/* Mailbox and Mask Registers bits */
 154#define RCAR_CAN_IDE            (1 << 31)
 155#define RCAR_CAN_RTR            (1 << 30)
 156#define RCAR_CAN_SID_SHIFT      18
 157
 158/* Mailbox Interrupt Enable Register 1 bits */
 159#define RCAR_CAN_MIER1_RXFIE    (1 << 28) /* Receive  FIFO Interrupt Enable */
 160#define RCAR_CAN_MIER1_TXFIE    (1 << 24) /* Transmit FIFO Interrupt Enable */
 161
 162/* Interrupt Enable Register bits */
 163#define RCAR_CAN_IER_ERSIE      (1 << 5) /* Error (ERS) Interrupt Enable Bit */
 164#define RCAR_CAN_IER_RXFIE      (1 << 4) /* Reception FIFO Interrupt */
 165                                        /* Enable Bit */
 166#define RCAR_CAN_IER_TXFIE      (1 << 3) /* Transmission FIFO Interrupt */
 167                                        /* Enable Bit */
 168/* Interrupt Status Register bits */
 169#define RCAR_CAN_ISR_ERSF       (1 << 5) /* Error (ERS) Interrupt Status Bit */
 170#define RCAR_CAN_ISR_RXFF       (1 << 4) /* Reception FIFO Interrupt */
 171                                        /* Status Bit */
 172#define RCAR_CAN_ISR_TXFF       (1 << 3) /* Transmission FIFO Interrupt */
 173                                        /* Status Bit */
 174
 175/* Error Interrupt Enable Register bits */
 176#define RCAR_CAN_EIER_BLIE      (1 << 7) /* Bus Lock Interrupt Enable */
 177#define RCAR_CAN_EIER_OLIE      (1 << 6) /* Overload Frame Transmit */
 178                                        /* Interrupt Enable */
 179#define RCAR_CAN_EIER_ORIE      (1 << 5) /* Receive Overrun  Interrupt Enable */
 180#define RCAR_CAN_EIER_BORIE     (1 << 4) /* Bus-Off Recovery Interrupt Enable */
 181#define RCAR_CAN_EIER_BOEIE     (1 << 3) /* Bus-Off Entry Interrupt Enable */
 182#define RCAR_CAN_EIER_EPIE      (1 << 2) /* Error Passive Interrupt Enable */
 183#define RCAR_CAN_EIER_EWIE      (1 << 1) /* Error Warning Interrupt Enable */
 184#define RCAR_CAN_EIER_BEIE      (1 << 0) /* Bus Error Interrupt Enable */
 185
 186/* Error Interrupt Factor Judge Register bits */
 187#define RCAR_CAN_EIFR_BLIF      (1 << 7) /* Bus Lock Detect Flag */
 188#define RCAR_CAN_EIFR_OLIF      (1 << 6) /* Overload Frame Transmission */
 189                                         /* Detect Flag */
 190#define RCAR_CAN_EIFR_ORIF      (1 << 5) /* Receive Overrun Detect Flag */
 191#define RCAR_CAN_EIFR_BORIF     (1 << 4) /* Bus-Off Recovery Detect Flag */
 192#define RCAR_CAN_EIFR_BOEIF     (1 << 3) /* Bus-Off Entry Detect Flag */
 193#define RCAR_CAN_EIFR_EPIF      (1 << 2) /* Error Passive Detect Flag */
 194#define RCAR_CAN_EIFR_EWIF      (1 << 1) /* Error Warning Detect Flag */
 195#define RCAR_CAN_EIFR_BEIF      (1 << 0) /* Bus Error Detect Flag */
 196
 197/* Error Code Store Register bits */
 198#define RCAR_CAN_ECSR_EDPM      (1 << 7) /* Error Display Mode Select Bit */
 199#define RCAR_CAN_ECSR_ADEF      (1 << 6) /* ACK Delimiter Error Flag */
 200#define RCAR_CAN_ECSR_BE0F      (1 << 5) /* Bit Error (dominant) Flag */
 201#define RCAR_CAN_ECSR_BE1F      (1 << 4) /* Bit Error (recessive) Flag */
 202#define RCAR_CAN_ECSR_CEF       (1 << 3) /* CRC Error Flag */
 203#define RCAR_CAN_ECSR_AEF       (1 << 2) /* ACK Error Flag */
 204#define RCAR_CAN_ECSR_FEF       (1 << 1) /* Form Error Flag */
 205#define RCAR_CAN_ECSR_SEF       (1 << 0) /* Stuff Error Flag */
 206
 207#define RCAR_CAN_NAPI_WEIGHT    4
 208#define MAX_STR_READS           0x100
 209
 210static void tx_failure_cleanup(struct net_device *ndev)
 211{
 212        int i;
 213
 214        for (i = 0; i < RCAR_CAN_FIFO_DEPTH; i++)
 215                can_free_echo_skb(ndev, i);
 216}
 217
 218static void rcar_can_error(struct net_device *ndev)
 219{
 220        struct rcar_can_priv *priv = netdev_priv(ndev);
 221        struct net_device_stats *stats = &ndev->stats;
 222        struct can_frame *cf;
 223        struct sk_buff *skb;
 224        u8 eifr, txerr = 0, rxerr = 0;
 225
 226        /* Propagate the error condition to the CAN stack */
 227        skb = alloc_can_err_skb(ndev, &cf);
 228
 229        eifr = readb(&priv->regs->eifr);
 230        if (eifr & (RCAR_CAN_EIFR_EWIF | RCAR_CAN_EIFR_EPIF)) {
 231                txerr = readb(&priv->regs->tecr);
 232                rxerr = readb(&priv->regs->recr);
 233                if (skb) {
 234                        cf->can_id |= CAN_ERR_CRTL;
 235                        cf->data[6] = txerr;
 236                        cf->data[7] = rxerr;
 237                }
 238        }
 239        if (eifr & RCAR_CAN_EIFR_BEIF) {
 240                int rx_errors = 0, tx_errors = 0;
 241                u8 ecsr;
 242
 243                netdev_dbg(priv->ndev, "Bus error interrupt:\n");
 244                if (skb) {
 245                        cf->can_id |= CAN_ERR_BUSERROR | CAN_ERR_PROT;
 246                        cf->data[2] = CAN_ERR_PROT_UNSPEC;
 247                }
 248                ecsr = readb(&priv->regs->ecsr);
 249                if (ecsr & RCAR_CAN_ECSR_ADEF) {
 250                        netdev_dbg(priv->ndev, "ACK Delimiter Error\n");
 251                        tx_errors++;
 252                        writeb(~RCAR_CAN_ECSR_ADEF, &priv->regs->ecsr);
 253                        if (skb)
 254                                cf->data[3] |= CAN_ERR_PROT_LOC_ACK_DEL;
 255                }
 256                if (ecsr & RCAR_CAN_ECSR_BE0F) {
 257                        netdev_dbg(priv->ndev, "Bit Error (dominant)\n");
 258                        tx_errors++;
 259                        writeb(~RCAR_CAN_ECSR_BE0F, &priv->regs->ecsr);
 260                        if (skb)
 261                                cf->data[2] |= CAN_ERR_PROT_BIT0;
 262                }
 263                if (ecsr & RCAR_CAN_ECSR_BE1F) {
 264                        netdev_dbg(priv->ndev, "Bit Error (recessive)\n");
 265                        tx_errors++;
 266                        writeb(~RCAR_CAN_ECSR_BE1F, &priv->regs->ecsr);
 267                        if (skb)
 268                                cf->data[2] |= CAN_ERR_PROT_BIT1;
 269                }
 270                if (ecsr & RCAR_CAN_ECSR_CEF) {
 271                        netdev_dbg(priv->ndev, "CRC Error\n");
 272                        rx_errors++;
 273                        writeb(~RCAR_CAN_ECSR_CEF, &priv->regs->ecsr);
 274                        if (skb)
 275                                cf->data[3] |= CAN_ERR_PROT_LOC_CRC_SEQ;
 276                }
 277                if (ecsr & RCAR_CAN_ECSR_AEF) {
 278                        netdev_dbg(priv->ndev, "ACK Error\n");
 279                        tx_errors++;
 280                        writeb(~RCAR_CAN_ECSR_AEF, &priv->regs->ecsr);
 281                        if (skb) {
 282                                cf->can_id |= CAN_ERR_ACK;
 283                                cf->data[3] |= CAN_ERR_PROT_LOC_ACK;
 284                        }
 285                }
 286                if (ecsr & RCAR_CAN_ECSR_FEF) {
 287                        netdev_dbg(priv->ndev, "Form Error\n");
 288                        rx_errors++;
 289                        writeb(~RCAR_CAN_ECSR_FEF, &priv->regs->ecsr);
 290                        if (skb)
 291                                cf->data[2] |= CAN_ERR_PROT_FORM;
 292                }
 293                if (ecsr & RCAR_CAN_ECSR_SEF) {
 294                        netdev_dbg(priv->ndev, "Stuff Error\n");
 295                        rx_errors++;
 296                        writeb(~RCAR_CAN_ECSR_SEF, &priv->regs->ecsr);
 297                        if (skb)
 298                                cf->data[2] |= CAN_ERR_PROT_STUFF;
 299                }
 300
 301                priv->can.can_stats.bus_error++;
 302                ndev->stats.rx_errors += rx_errors;
 303                ndev->stats.tx_errors += tx_errors;
 304                writeb(~RCAR_CAN_EIFR_BEIF, &priv->regs->eifr);
 305        }
 306        if (eifr & RCAR_CAN_EIFR_EWIF) {
 307                netdev_dbg(priv->ndev, "Error warning interrupt\n");
 308                priv->can.state = CAN_STATE_ERROR_WARNING;
 309                priv->can.can_stats.error_warning++;
 310                /* Clear interrupt condition */
 311                writeb(~RCAR_CAN_EIFR_EWIF, &priv->regs->eifr);
 312                if (skb)
 313                        cf->data[1] = txerr > rxerr ? CAN_ERR_CRTL_TX_WARNING :
 314                                              CAN_ERR_CRTL_RX_WARNING;
 315        }
 316        if (eifr & RCAR_CAN_EIFR_EPIF) {
 317                netdev_dbg(priv->ndev, "Error passive interrupt\n");
 318                priv->can.state = CAN_STATE_ERROR_PASSIVE;
 319                priv->can.can_stats.error_passive++;
 320                /* Clear interrupt condition */
 321                writeb(~RCAR_CAN_EIFR_EPIF, &priv->regs->eifr);
 322                if (skb)
 323                        cf->data[1] = txerr > rxerr ? CAN_ERR_CRTL_TX_PASSIVE :
 324                                              CAN_ERR_CRTL_RX_PASSIVE;
 325        }
 326        if (eifr & RCAR_CAN_EIFR_BOEIF) {
 327                netdev_dbg(priv->ndev, "Bus-off entry interrupt\n");
 328                tx_failure_cleanup(ndev);
 329                priv->ier = RCAR_CAN_IER_ERSIE;
 330                writeb(priv->ier, &priv->regs->ier);
 331                priv->can.state = CAN_STATE_BUS_OFF;
 332                /* Clear interrupt condition */
 333                writeb(~RCAR_CAN_EIFR_BOEIF, &priv->regs->eifr);
 334                can_bus_off(ndev);
 335                if (skb)
 336                        cf->can_id |= CAN_ERR_BUSOFF;
 337        }
 338        if (eifr & RCAR_CAN_EIFR_ORIF) {
 339                netdev_dbg(priv->ndev, "Receive overrun error interrupt\n");
 340                ndev->stats.rx_over_errors++;
 341                ndev->stats.rx_errors++;
 342                writeb(~RCAR_CAN_EIFR_ORIF, &priv->regs->eifr);
 343                if (skb) {
 344                        cf->can_id |= CAN_ERR_CRTL;
 345                        cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
 346                }
 347        }
 348        if (eifr & RCAR_CAN_EIFR_OLIF) {
 349                netdev_dbg(priv->ndev,
 350                           "Overload Frame Transmission error interrupt\n");
 351                ndev->stats.rx_over_errors++;
 352                ndev->stats.rx_errors++;
 353                writeb(~RCAR_CAN_EIFR_OLIF, &priv->regs->eifr);
 354                if (skb) {
 355                        cf->can_id |= CAN_ERR_PROT;
 356                        cf->data[2] |= CAN_ERR_PROT_OVERLOAD;
 357                }
 358        }
 359
 360        if (skb) {
 361                stats->rx_packets++;
 362                stats->rx_bytes += cf->can_dlc;
 363                netif_rx(skb);
 364        }
 365}
 366
 367static void rcar_can_tx_done(struct net_device *ndev)
 368{
 369        struct rcar_can_priv *priv = netdev_priv(ndev);
 370        struct net_device_stats *stats = &ndev->stats;
 371        u8 isr;
 372
 373        while (1) {
 374                u8 unsent = readb(&priv->regs->tfcr);
 375
 376                unsent = (unsent & RCAR_CAN_TFCR_TFUST) >>
 377                          RCAR_CAN_TFCR_TFUST_SHIFT;
 378                if (priv->tx_head - priv->tx_tail <= unsent)
 379                        break;
 380                stats->tx_packets++;
 381                stats->tx_bytes += priv->tx_dlc[priv->tx_tail %
 382                                                RCAR_CAN_FIFO_DEPTH];
 383                priv->tx_dlc[priv->tx_tail % RCAR_CAN_FIFO_DEPTH] = 0;
 384                can_get_echo_skb(ndev, priv->tx_tail % RCAR_CAN_FIFO_DEPTH);
 385                priv->tx_tail++;
 386                netif_wake_queue(ndev);
 387        }
 388        /* Clear interrupt */
 389        isr = readb(&priv->regs->isr);
 390        writeb(isr & ~RCAR_CAN_ISR_TXFF, &priv->regs->isr);
 391        can_led_event(ndev, CAN_LED_EVENT_TX);
 392}
 393
 394static irqreturn_t rcar_can_interrupt(int irq, void *dev_id)
 395{
 396        struct net_device *ndev = dev_id;
 397        struct rcar_can_priv *priv = netdev_priv(ndev);
 398        u8 isr;
 399
 400        isr = readb(&priv->regs->isr);
 401        if (!(isr & priv->ier))
 402                return IRQ_NONE;
 403
 404        if (isr & RCAR_CAN_ISR_ERSF)
 405                rcar_can_error(ndev);
 406
 407        if (isr & RCAR_CAN_ISR_TXFF)
 408                rcar_can_tx_done(ndev);
 409
 410        if (isr & RCAR_CAN_ISR_RXFF) {
 411                if (napi_schedule_prep(&priv->napi)) {
 412                        /* Disable Rx FIFO interrupts */
 413                        priv->ier &= ~RCAR_CAN_IER_RXFIE;
 414                        writeb(priv->ier, &priv->regs->ier);
 415                        __napi_schedule(&priv->napi);
 416                }
 417        }
 418
 419        return IRQ_HANDLED;
 420}
 421
 422static void rcar_can_set_bittiming(struct net_device *dev)
 423{
 424        struct rcar_can_priv *priv = netdev_priv(dev);
 425        struct can_bittiming *bt = &priv->can.bittiming;
 426        u32 bcr;
 427
 428        bcr = RCAR_CAN_BCR_TSEG1(bt->phase_seg1 + bt->prop_seg - 1) |
 429              RCAR_CAN_BCR_BPR(bt->brp - 1) | RCAR_CAN_BCR_SJW(bt->sjw - 1) |
 430              RCAR_CAN_BCR_TSEG2(bt->phase_seg2 - 1);
 431        /* Don't overwrite CLKR with 32-bit BCR access; CLKR has 8-bit access.
 432         * All the registers are big-endian but they get byte-swapped on 32-bit
 433         * read/write (but not on 8-bit, contrary to the manuals)...
 434         */
 435        writel((bcr << 8) | priv->clock_select, &priv->regs->bcr);
 436}
 437
 438static void rcar_can_start(struct net_device *ndev)
 439{
 440        struct rcar_can_priv *priv = netdev_priv(ndev);
 441        u16 ctlr;
 442        int i;
 443
 444        /* Set controller to known mode:
 445         * - FIFO mailbox mode
 446         * - accept all messages
 447         * - overrun mode
 448         * CAN is in sleep mode after MCU hardware or software reset.
 449         */
 450        ctlr = readw(&priv->regs->ctlr);
 451        ctlr &= ~RCAR_CAN_CTLR_SLPM;
 452        writew(ctlr, &priv->regs->ctlr);
 453        /* Go to reset mode */
 454        ctlr |= RCAR_CAN_CTLR_CANM_FORCE_RESET;
 455        writew(ctlr, &priv->regs->ctlr);
 456        for (i = 0; i < MAX_STR_READS; i++) {
 457                if (readw(&priv->regs->str) & RCAR_CAN_STR_RSTST)
 458                        break;
 459        }
 460        rcar_can_set_bittiming(ndev);
 461        ctlr |= RCAR_CAN_CTLR_IDFM_MIXED; /* Select mixed ID mode */
 462        ctlr |= RCAR_CAN_CTLR_BOM_ENT;  /* Entry to halt mode automatically */
 463                                        /* at bus-off */
 464        ctlr |= RCAR_CAN_CTLR_MBM;      /* Select FIFO mailbox mode */
 465        ctlr |= RCAR_CAN_CTLR_MLM;      /* Overrun mode */
 466        writew(ctlr, &priv->regs->ctlr);
 467
 468        /* Accept all SID and EID */
 469        writel(0, &priv->regs->mkr_2_9[6]);
 470        writel(0, &priv->regs->mkr_2_9[7]);
 471        /* In FIFO mailbox mode, write "0" to bits 24 to 31 */
 472        writel(0, &priv->regs->mkivlr1);
 473        /* Accept all frames */
 474        writel(0, &priv->regs->fidcr[0]);
 475        writel(RCAR_CAN_FIDCR_IDE | RCAR_CAN_FIDCR_RTR, &priv->regs->fidcr[1]);
 476        /* Enable and configure FIFO mailbox interrupts */
 477        writel(RCAR_CAN_MIER1_RXFIE | RCAR_CAN_MIER1_TXFIE, &priv->regs->mier1);
 478
 479        priv->ier = RCAR_CAN_IER_ERSIE | RCAR_CAN_IER_RXFIE |
 480                    RCAR_CAN_IER_TXFIE;
 481        writeb(priv->ier, &priv->regs->ier);
 482
 483        /* Accumulate error codes */
 484        writeb(RCAR_CAN_ECSR_EDPM, &priv->regs->ecsr);
 485        /* Enable error interrupts */
 486        writeb(RCAR_CAN_EIER_EWIE | RCAR_CAN_EIER_EPIE | RCAR_CAN_EIER_BOEIE |
 487               (priv->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING ?
 488               RCAR_CAN_EIER_BEIE : 0) | RCAR_CAN_EIER_ORIE |
 489               RCAR_CAN_EIER_OLIE, &priv->regs->eier);
 490        priv->can.state = CAN_STATE_ERROR_ACTIVE;
 491
 492        /* Go to operation mode */
 493        writew(ctlr & ~RCAR_CAN_CTLR_CANM, &priv->regs->ctlr);
 494        for (i = 0; i < MAX_STR_READS; i++) {
 495                if (!(readw(&priv->regs->str) & RCAR_CAN_STR_RSTST))
 496                        break;
 497        }
 498        /* Enable Rx and Tx FIFO */
 499        writeb(RCAR_CAN_RFCR_RFE, &priv->regs->rfcr);
 500        writeb(RCAR_CAN_TFCR_TFE, &priv->regs->tfcr);
 501}
 502
 503static int rcar_can_open(struct net_device *ndev)
 504{
 505        struct rcar_can_priv *priv = netdev_priv(ndev);
 506        int err;
 507
 508        err = clk_prepare_enable(priv->clk);
 509        if (err) {
 510                netdev_err(ndev, "failed to enable periperal clock, error %d\n",
 511                           err);
 512                goto out;
 513        }
 514        err = clk_prepare_enable(priv->can_clk);
 515        if (err) {
 516                netdev_err(ndev, "failed to enable CAN clock, error %d\n",
 517                           err);
 518                goto out_clock;
 519        }
 520        err = open_candev(ndev);
 521        if (err) {
 522                netdev_err(ndev, "open_candev() failed, error %d\n", err);
 523                goto out_can_clock;
 524        }
 525        napi_enable(&priv->napi);
 526        err = request_irq(ndev->irq, rcar_can_interrupt, 0, ndev->name, ndev);
 527        if (err) {
 528                netdev_err(ndev, "error requesting interrupt %x\n", ndev->irq);
 529                goto out_close;
 530        }
 531        can_led_event(ndev, CAN_LED_EVENT_OPEN);
 532        rcar_can_start(ndev);
 533        netif_start_queue(ndev);
 534        return 0;
 535out_close:
 536        napi_disable(&priv->napi);
 537        close_candev(ndev);
 538out_can_clock:
 539        clk_disable_unprepare(priv->can_clk);
 540out_clock:
 541        clk_disable_unprepare(priv->clk);
 542out:
 543        return err;
 544}
 545
 546static void rcar_can_stop(struct net_device *ndev)
 547{
 548        struct rcar_can_priv *priv = netdev_priv(ndev);
 549        u16 ctlr;
 550        int i;
 551
 552        /* Go to (force) reset mode */
 553        ctlr = readw(&priv->regs->ctlr);
 554        ctlr |= RCAR_CAN_CTLR_CANM_FORCE_RESET;
 555        writew(ctlr, &priv->regs->ctlr);
 556        for (i = 0; i < MAX_STR_READS; i++) {
 557                if (readw(&priv->regs->str) & RCAR_CAN_STR_RSTST)
 558                        break;
 559        }
 560        writel(0, &priv->regs->mier0);
 561        writel(0, &priv->regs->mier1);
 562        writeb(0, &priv->regs->ier);
 563        writeb(0, &priv->regs->eier);
 564        /* Go to sleep mode */
 565        ctlr |= RCAR_CAN_CTLR_SLPM;
 566        writew(ctlr, &priv->regs->ctlr);
 567        priv->can.state = CAN_STATE_STOPPED;
 568}
 569
 570static int rcar_can_close(struct net_device *ndev)
 571{
 572        struct rcar_can_priv *priv = netdev_priv(ndev);
 573
 574        netif_stop_queue(ndev);
 575        rcar_can_stop(ndev);
 576        free_irq(ndev->irq, ndev);
 577        napi_disable(&priv->napi);
 578        clk_disable_unprepare(priv->can_clk);
 579        clk_disable_unprepare(priv->clk);
 580        close_candev(ndev);
 581        can_led_event(ndev, CAN_LED_EVENT_STOP);
 582        return 0;
 583}
 584
 585static netdev_tx_t rcar_can_start_xmit(struct sk_buff *skb,
 586                                       struct net_device *ndev)
 587{
 588        struct rcar_can_priv *priv = netdev_priv(ndev);
 589        struct can_frame *cf = (struct can_frame *)skb->data;
 590        u32 data, i;
 591
 592        if (can_dropped_invalid_skb(ndev, skb))
 593                return NETDEV_TX_OK;
 594
 595        if (cf->can_id & CAN_EFF_FLAG)  /* Extended frame format */
 596                data = (cf->can_id & CAN_EFF_MASK) | RCAR_CAN_IDE;
 597        else                            /* Standard frame format */
 598                data = (cf->can_id & CAN_SFF_MASK) << RCAR_CAN_SID_SHIFT;
 599
 600        if (cf->can_id & CAN_RTR_FLAG) { /* Remote transmission request */
 601                data |= RCAR_CAN_RTR;
 602        } else {
 603                for (i = 0; i < cf->can_dlc; i++)
 604                        writeb(cf->data[i],
 605                               &priv->regs->mb[RCAR_CAN_TX_FIFO_MBX].data[i]);
 606        }
 607
 608        writel(data, &priv->regs->mb[RCAR_CAN_TX_FIFO_MBX].id);
 609
 610        writeb(cf->can_dlc, &priv->regs->mb[RCAR_CAN_TX_FIFO_MBX].dlc);
 611
 612        priv->tx_dlc[priv->tx_head % RCAR_CAN_FIFO_DEPTH] = cf->can_dlc;
 613        can_put_echo_skb(skb, ndev, priv->tx_head % RCAR_CAN_FIFO_DEPTH);
 614        priv->tx_head++;
 615        /* Start Tx: write 0xff to the TFPCR register to increment
 616         * the CPU-side pointer for the transmit FIFO to the next
 617         * mailbox location
 618         */
 619        writeb(0xff, &priv->regs->tfpcr);
 620        /* Stop the queue if we've filled all FIFO entries */
 621        if (priv->tx_head - priv->tx_tail >= RCAR_CAN_FIFO_DEPTH)
 622                netif_stop_queue(ndev);
 623
 624        return NETDEV_TX_OK;
 625}
 626
 627static const struct net_device_ops rcar_can_netdev_ops = {
 628        .ndo_open = rcar_can_open,
 629        .ndo_stop = rcar_can_close,
 630        .ndo_start_xmit = rcar_can_start_xmit,
 631        .ndo_change_mtu = can_change_mtu,
 632};
 633
 634static void rcar_can_rx_pkt(struct rcar_can_priv *priv)
 635{
 636        struct net_device_stats *stats = &priv->ndev->stats;
 637        struct can_frame *cf;
 638        struct sk_buff *skb;
 639        u32 data;
 640        u8 dlc;
 641
 642        skb = alloc_can_skb(priv->ndev, &cf);
 643        if (!skb) {
 644                stats->rx_dropped++;
 645                return;
 646        }
 647
 648        data = readl(&priv->regs->mb[RCAR_CAN_RX_FIFO_MBX].id);
 649        if (data & RCAR_CAN_IDE)
 650                cf->can_id = (data & CAN_EFF_MASK) | CAN_EFF_FLAG;
 651        else
 652                cf->can_id = (data >> RCAR_CAN_SID_SHIFT) & CAN_SFF_MASK;
 653
 654        dlc = readb(&priv->regs->mb[RCAR_CAN_RX_FIFO_MBX].dlc);
 655        cf->can_dlc = get_can_dlc(dlc);
 656        if (data & RCAR_CAN_RTR) {
 657                cf->can_id |= CAN_RTR_FLAG;
 658        } else {
 659                for (dlc = 0; dlc < cf->can_dlc; dlc++)
 660                        cf->data[dlc] =
 661                        readb(&priv->regs->mb[RCAR_CAN_RX_FIFO_MBX].data[dlc]);
 662        }
 663
 664        can_led_event(priv->ndev, CAN_LED_EVENT_RX);
 665
 666        stats->rx_bytes += cf->can_dlc;
 667        stats->rx_packets++;
 668        netif_receive_skb(skb);
 669}
 670
 671static int rcar_can_rx_poll(struct napi_struct *napi, int quota)
 672{
 673        struct rcar_can_priv *priv = container_of(napi,
 674                                                  struct rcar_can_priv, napi);
 675        int num_pkts;
 676
 677        for (num_pkts = 0; num_pkts < quota; num_pkts++) {
 678                u8 rfcr, isr;
 679
 680                isr = readb(&priv->regs->isr);
 681                /* Clear interrupt bit */
 682                if (isr & RCAR_CAN_ISR_RXFF)
 683                        writeb(isr & ~RCAR_CAN_ISR_RXFF, &priv->regs->isr);
 684                rfcr = readb(&priv->regs->rfcr);
 685                if (rfcr & RCAR_CAN_RFCR_RFEST)
 686                        break;
 687                rcar_can_rx_pkt(priv);
 688                /* Write 0xff to the RFPCR register to increment
 689                 * the CPU-side pointer for the receive FIFO
 690                 * to the next mailbox location
 691                 */
 692                writeb(0xff, &priv->regs->rfpcr);
 693        }
 694        /* All packets processed */
 695        if (num_pkts < quota) {
 696                napi_complete(napi);
 697                priv->ier |= RCAR_CAN_IER_RXFIE;
 698                writeb(priv->ier, &priv->regs->ier);
 699        }
 700        return num_pkts;
 701}
 702
 703static int rcar_can_do_set_mode(struct net_device *ndev, enum can_mode mode)
 704{
 705        switch (mode) {
 706        case CAN_MODE_START:
 707                rcar_can_start(ndev);
 708                netif_wake_queue(ndev);
 709                return 0;
 710        default:
 711                return -EOPNOTSUPP;
 712        }
 713}
 714
 715static int rcar_can_get_berr_counter(const struct net_device *dev,
 716                                     struct can_berr_counter *bec)
 717{
 718        struct rcar_can_priv *priv = netdev_priv(dev);
 719        int err;
 720
 721        err = clk_prepare_enable(priv->clk);
 722        if (err)
 723                return err;
 724        bec->txerr = readb(&priv->regs->tecr);
 725        bec->rxerr = readb(&priv->regs->recr);
 726        clk_disable_unprepare(priv->clk);
 727        return 0;
 728}
 729
 730static const char * const clock_names[] = {
 731        [CLKR_CLKP1]    = "clkp1",
 732        [CLKR_CLKP2]    = "clkp2",
 733        [CLKR_CLKEXT]   = "can_clk",
 734};
 735
 736static int rcar_can_probe(struct platform_device *pdev)
 737{
 738        struct rcar_can_platform_data *pdata;
 739        struct rcar_can_priv *priv;
 740        struct net_device *ndev;
 741        struct resource *mem;
 742        void __iomem *addr;
 743        u32 clock_select = CLKR_CLKP1;
 744        int err = -ENODEV;
 745        int irq;
 746
 747        if (pdev->dev.of_node) {
 748                of_property_read_u32(pdev->dev.of_node,
 749                                     "renesas,can-clock-select", &clock_select);
 750        } else {
 751                pdata = dev_get_platdata(&pdev->dev);
 752                if (!pdata) {
 753                        dev_err(&pdev->dev, "No platform data provided!\n");
 754                        goto fail;
 755                }
 756                clock_select = pdata->clock_select;
 757        }
 758
 759        irq = platform_get_irq(pdev, 0);
 760        if (!irq) {
 761                dev_err(&pdev->dev, "No IRQ resource\n");
 762                goto fail;
 763        }
 764
 765        mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 766        addr = devm_ioremap_resource(&pdev->dev, mem);
 767        if (IS_ERR(addr)) {
 768                err = PTR_ERR(addr);
 769                goto fail;
 770        }
 771
 772        ndev = alloc_candev(sizeof(struct rcar_can_priv), RCAR_CAN_FIFO_DEPTH);
 773        if (!ndev) {
 774                dev_err(&pdev->dev, "alloc_candev() failed\n");
 775                err = -ENOMEM;
 776                goto fail;
 777        }
 778
 779        priv = netdev_priv(ndev);
 780
 781        priv->clk = devm_clk_get(&pdev->dev, "clkp1");
 782        if (IS_ERR(priv->clk)) {
 783                err = PTR_ERR(priv->clk);
 784                dev_err(&pdev->dev, "cannot get peripheral clock: %d\n", err);
 785                goto fail_clk;
 786        }
 787
 788        if (clock_select >= ARRAY_SIZE(clock_names)) {
 789                err = -EINVAL;
 790                dev_err(&pdev->dev, "invalid CAN clock selected\n");
 791                goto fail_clk;
 792        }
 793        priv->can_clk = devm_clk_get(&pdev->dev, clock_names[clock_select]);
 794        if (IS_ERR(priv->can_clk)) {
 795                err = PTR_ERR(priv->can_clk);
 796                dev_err(&pdev->dev, "cannot get CAN clock: %d\n", err);
 797                goto fail_clk;
 798        }
 799
 800        ndev->netdev_ops = &rcar_can_netdev_ops;
 801        ndev->irq = irq;
 802        ndev->flags |= IFF_ECHO;
 803        priv->ndev = ndev;
 804        priv->regs = addr;
 805        priv->clock_select = clock_select;
 806        priv->can.clock.freq = clk_get_rate(priv->can_clk);
 807        priv->can.bittiming_const = &rcar_can_bittiming_const;
 808        priv->can.do_set_mode = rcar_can_do_set_mode;
 809        priv->can.do_get_berr_counter = rcar_can_get_berr_counter;
 810        priv->can.ctrlmode_supported = CAN_CTRLMODE_BERR_REPORTING;
 811        platform_set_drvdata(pdev, ndev);
 812        SET_NETDEV_DEV(ndev, &pdev->dev);
 813
 814        netif_napi_add(ndev, &priv->napi, rcar_can_rx_poll,
 815                       RCAR_CAN_NAPI_WEIGHT);
 816        err = register_candev(ndev);
 817        if (err) {
 818                dev_err(&pdev->dev, "register_candev() failed, error %d\n",
 819                        err);
 820                goto fail_candev;
 821        }
 822
 823        devm_can_led_init(ndev);
 824
 825        dev_info(&pdev->dev, "device registered (reg_base=%p, irq=%u)\n",
 826                 priv->regs, ndev->irq);
 827
 828        return 0;
 829fail_candev:
 830        netif_napi_del(&priv->napi);
 831fail_clk:
 832        free_candev(ndev);
 833fail:
 834        return err;
 835}
 836
 837static int rcar_can_remove(struct platform_device *pdev)
 838{
 839        struct net_device *ndev = platform_get_drvdata(pdev);
 840        struct rcar_can_priv *priv = netdev_priv(ndev);
 841
 842        unregister_candev(ndev);
 843        netif_napi_del(&priv->napi);
 844        free_candev(ndev);
 845        return 0;
 846}
 847
 848static int __maybe_unused rcar_can_suspend(struct device *dev)
 849{
 850        struct net_device *ndev = dev_get_drvdata(dev);
 851        struct rcar_can_priv *priv = netdev_priv(ndev);
 852        u16 ctlr;
 853
 854        if (netif_running(ndev)) {
 855                netif_stop_queue(ndev);
 856                netif_device_detach(ndev);
 857        }
 858        ctlr = readw(&priv->regs->ctlr);
 859        ctlr |= RCAR_CAN_CTLR_CANM_HALT;
 860        writew(ctlr, &priv->regs->ctlr);
 861        ctlr |= RCAR_CAN_CTLR_SLPM;
 862        writew(ctlr, &priv->regs->ctlr);
 863        priv->can.state = CAN_STATE_SLEEPING;
 864
 865        clk_disable(priv->clk);
 866        return 0;
 867}
 868
 869static int __maybe_unused rcar_can_resume(struct device *dev)
 870{
 871        struct net_device *ndev = dev_get_drvdata(dev);
 872        struct rcar_can_priv *priv = netdev_priv(ndev);
 873        u16 ctlr;
 874        int err;
 875
 876        err = clk_enable(priv->clk);
 877        if (err) {
 878                netdev_err(ndev, "clk_enable() failed, error %d\n", err);
 879                return err;
 880        }
 881
 882        ctlr = readw(&priv->regs->ctlr);
 883        ctlr &= ~RCAR_CAN_CTLR_SLPM;
 884        writew(ctlr, &priv->regs->ctlr);
 885        ctlr &= ~RCAR_CAN_CTLR_CANM;
 886        writew(ctlr, &priv->regs->ctlr);
 887        priv->can.state = CAN_STATE_ERROR_ACTIVE;
 888
 889        if (netif_running(ndev)) {
 890                netif_device_attach(ndev);
 891                netif_start_queue(ndev);
 892        }
 893        return 0;
 894}
 895
 896static SIMPLE_DEV_PM_OPS(rcar_can_pm_ops, rcar_can_suspend, rcar_can_resume);
 897
 898static const struct of_device_id rcar_can_of_table[] __maybe_unused = {
 899        { .compatible = "renesas,can-r8a7778" },
 900        { .compatible = "renesas,can-r8a7779" },
 901        { .compatible = "renesas,can-r8a7790" },
 902        { .compatible = "renesas,can-r8a7791" },
 903        { }
 904};
 905MODULE_DEVICE_TABLE(of, rcar_can_of_table);
 906
 907static struct platform_driver rcar_can_driver = {
 908        .driver = {
 909                .name = RCAR_CAN_DRV_NAME,
 910                .of_match_table = of_match_ptr(rcar_can_of_table),
 911                .pm = &rcar_can_pm_ops,
 912        },
 913        .probe = rcar_can_probe,
 914        .remove = rcar_can_remove,
 915};
 916
 917module_platform_driver(rcar_can_driver);
 918
 919MODULE_AUTHOR("Cogent Embedded, Inc.");
 920MODULE_LICENSE("GPL");
 921MODULE_DESCRIPTION("CAN driver for Renesas R-Car SoC");
 922MODULE_ALIAS("platform:" RCAR_CAN_DRV_NAME);
 923
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