// SPDX-License-Identifier: GPL-2.0
//
// flexcan.c - FLEXCAN CAN controller driver
//
// Copyright (c) 2005-2006 Varma Electronics Oy
// Copyright (c) 2009 Sascha Hauer, Pengutronix
// Copyright (c) 2010-2017 Pengutronix, Marc Kleine-Budde <kernel@pengutronix.de>
// Copyright (c) 2014 David Jander, Protonic Holland
//
// Based on code originally by Andrey Volkov <avolkov@varma-el.com>

#include <dt-bindings/firmware/imx/rsrc.h>
#include <linux/bitfield.h>
#include <linux/can.h>
#include <linux/can/dev.h>
#include <linux/can/error.h>
#include <linux/can/led.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/firmware/imx/sci.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/pinctrl/consumer.h>
#include <linux/platform_device.h>
#include <linux/can/platform/flexcan.h>
#include <linux/pm_runtime.h>
#include <linux/regmap.h>
#include <linux/regulator/consumer.h>

#include "flexcan.h"

#define DRV_NAME                        "flexcan"

/* 8 for RX fifo and 2 error handling */
#define FLEXCAN_NAPI_WEIGHT             (8 + 2)

/* FLEXCAN module configuration register (CANMCR) bits */
#define FLEXCAN_MCR_MDIS                BIT(31)
#define FLEXCAN_MCR_FRZ                 BIT(30)
#define FLEXCAN_MCR_FEN                 BIT(29)
#define FLEXCAN_MCR_HALT                BIT(28)
#define FLEXCAN_MCR_NOT_RDY             BIT(27)
#define FLEXCAN_MCR_WAK_MSK             BIT(26)
#define FLEXCAN_MCR_SOFTRST             BIT(25)
#define FLEXCAN_MCR_FRZ_ACK             BIT(24)
#define FLEXCAN_MCR_SUPV                BIT(23)
#define FLEXCAN_MCR_SLF_WAK             BIT(22)
#define FLEXCAN_MCR_WRN_EN              BIT(21)
#define FLEXCAN_MCR_LPM_ACK             BIT(20)
#define FLEXCAN_MCR_WAK_SRC             BIT(19)
#define FLEXCAN_MCR_DOZE                BIT(18)
#define FLEXCAN_MCR_SRX_DIS             BIT(17)
#define FLEXCAN_MCR_IRMQ                BIT(16)
#define FLEXCAN_MCR_LPRIO_EN            BIT(13)
#define FLEXCAN_MCR_AEN                 BIT(12)
#define FLEXCAN_MCR_FDEN                BIT(11)
/* MCR_MAXMB: maximum used MBs is MAXMB + 1 */
#define FLEXCAN_MCR_MAXMB(x)            ((x) & 0x7f)
#define FLEXCAN_MCR_IDAM_A              (0x0 << 8)
#define FLEXCAN_MCR_IDAM_B              (0x1 << 8)
#define FLEXCAN_MCR_IDAM_C              (0x2 << 8)
#define FLEXCAN_MCR_IDAM_D              (0x3 << 8)

/* FLEXCAN control register (CANCTRL) bits */
#define FLEXCAN_CTRL_PRESDIV(x)         (((x) & 0xff) << 24)
#define FLEXCAN_CTRL_RJW(x)             (((x) & 0x03) << 22)
#define FLEXCAN_CTRL_PSEG1(x)           (((x) & 0x07) << 19)
#define FLEXCAN_CTRL_PSEG2(x)           (((x) & 0x07) << 16)
#define FLEXCAN_CTRL_BOFF_MSK           BIT(15)
#define FLEXCAN_CTRL_ERR_MSK            BIT(14)
#define FLEXCAN_CTRL_CLK_SRC            BIT(13)
#define FLEXCAN_CTRL_LPB                BIT(12)
#define FLEXCAN_CTRL_TWRN_MSK           BIT(11)
#define FLEXCAN_CTRL_RWRN_MSK           BIT(10)
#define FLEXCAN_CTRL_SMP                BIT(7)
#define FLEXCAN_CTRL_BOFF_REC           BIT(6)
#define FLEXCAN_CTRL_TSYN               BIT(5)
#define FLEXCAN_CTRL_LBUF               BIT(4)
#define FLEXCAN_CTRL_LOM                BIT(3)
#define FLEXCAN_CTRL_PROPSEG(x)         ((x) & 0x07)
#define FLEXCAN_CTRL_ERR_BUS            (FLEXCAN_CTRL_ERR_MSK)
#define FLEXCAN_CTRL_ERR_STATE \
        (FLEXCAN_CTRL_TWRN_MSK | FLEXCAN_CTRL_RWRN_MSK | \
         FLEXCAN_CTRL_BOFF_MSK)
#define FLEXCAN_CTRL_ERR_ALL \
        (FLEXCAN_CTRL_ERR_BUS | FLEXCAN_CTRL_ERR_STATE)

/* FLEXCAN control register 2 (CTRL2) bits */
#define FLEXCAN_CTRL2_ECRWRE            BIT(29)
#define FLEXCAN_CTRL2_WRMFRZ            BIT(28)
#define FLEXCAN_CTRL2_RFFN(x)           (((x) & 0x0f) << 24)
#define FLEXCAN_CTRL2_TASD(x)           (((x) & 0x1f) << 19)
#define FLEXCAN_CTRL2_MRP               BIT(18)
#define FLEXCAN_CTRL2_RRS               BIT(17)
#define FLEXCAN_CTRL2_EACEN             BIT(16)
#define FLEXCAN_CTRL2_ISOCANFDEN        BIT(12)

/* FLEXCAN memory error control register (MECR) bits */
#define FLEXCAN_MECR_ECRWRDIS           BIT(31)
#define FLEXCAN_MECR_HANCEI_MSK         BIT(19)
#define FLEXCAN_MECR_FANCEI_MSK         BIT(18)
#define FLEXCAN_MECR_CEI_MSK            BIT(16)
#define FLEXCAN_MECR_HAERRIE            BIT(15)
#define FLEXCAN_MECR_FAERRIE            BIT(14)
#define FLEXCAN_MECR_EXTERRIE           BIT(13)
#define FLEXCAN_MECR_RERRDIS            BIT(9)
#define FLEXCAN_MECR_ECCDIS             BIT(8)
#define FLEXCAN_MECR_NCEFAFRZ           BIT(7)

/* FLEXCAN error and status register (ESR) bits */
#define FLEXCAN_ESR_TWRN_INT            BIT(17)
#define FLEXCAN_ESR_RWRN_INT            BIT(16)
#define FLEXCAN_ESR_BIT1_ERR            BIT(15)
#define FLEXCAN_ESR_BIT0_ERR            BIT(14)
#define FLEXCAN_ESR_ACK_ERR             BIT(13)
#define FLEXCAN_ESR_CRC_ERR             BIT(12)
#define FLEXCAN_ESR_FRM_ERR             BIT(11)
#define FLEXCAN_ESR_STF_ERR             BIT(10)
#define FLEXCAN_ESR_TX_WRN              BIT(9)
#define FLEXCAN_ESR_RX_WRN              BIT(8)
#define FLEXCAN_ESR_IDLE                BIT(7)
#define FLEXCAN_ESR_TXRX                BIT(6)
#define FLEXCAN_EST_FLT_CONF_SHIFT      (4)
#define FLEXCAN_ESR_FLT_CONF_MASK       (0x3 << FLEXCAN_EST_FLT_CONF_SHIFT)
#define FLEXCAN_ESR_FLT_CONF_ACTIVE     (0x0 << FLEXCAN_EST_FLT_CONF_SHIFT)
#define FLEXCAN_ESR_FLT_CONF_PASSIVE    (0x1 << FLEXCAN_EST_FLT_CONF_SHIFT)
#define FLEXCAN_ESR_BOFF_INT            BIT(2)
#define FLEXCAN_ESR_ERR_INT             BIT(1)
#define FLEXCAN_ESR_WAK_INT             BIT(0)
#define FLEXCAN_ESR_ERR_BUS \
        (FLEXCAN_ESR_BIT1_ERR | FLEXCAN_ESR_BIT0_ERR | \
         FLEXCAN_ESR_ACK_ERR | FLEXCAN_ESR_CRC_ERR | \
         FLEXCAN_ESR_FRM_ERR | FLEXCAN_ESR_STF_ERR)
#define FLEXCAN_ESR_ERR_STATE \
        (FLEXCAN_ESR_TWRN_INT | FLEXCAN_ESR_RWRN_INT | FLEXCAN_ESR_BOFF_INT)
#define FLEXCAN_ESR_ERR_ALL \
        (FLEXCAN_ESR_ERR_BUS | FLEXCAN_ESR_ERR_STATE)
#define FLEXCAN_ESR_ALL_INT \
        (FLEXCAN_ESR_TWRN_INT | FLEXCAN_ESR_RWRN_INT | \
         FLEXCAN_ESR_BOFF_INT | FLEXCAN_ESR_ERR_INT)

/* FLEXCAN Bit Timing register (CBT) bits */
#define FLEXCAN_CBT_BTF                 BIT(31)
#define FLEXCAN_CBT_EPRESDIV_MASK       GENMASK(30, 21)
#define FLEXCAN_CBT_ERJW_MASK           GENMASK(20, 16)
#define FLEXCAN_CBT_EPROPSEG_MASK       GENMASK(15, 10)
#define FLEXCAN_CBT_EPSEG1_MASK         GENMASK(9, 5)
#define FLEXCAN_CBT_EPSEG2_MASK         GENMASK(4, 0)

/* FLEXCAN FD control register (FDCTRL) bits */
#define FLEXCAN_FDCTRL_FDRATE           BIT(31)
#define FLEXCAN_FDCTRL_MBDSR1           GENMASK(20, 19)
#define FLEXCAN_FDCTRL_MBDSR0           GENMASK(17, 16)
#define FLEXCAN_FDCTRL_MBDSR_8          0x0
#define FLEXCAN_FDCTRL_MBDSR_12         0x1
#define FLEXCAN_FDCTRL_MBDSR_32         0x2
#define FLEXCAN_FDCTRL_MBDSR_64         0x3
#define FLEXCAN_FDCTRL_TDCEN            BIT(15)
#define FLEXCAN_FDCTRL_TDCFAIL          BIT(14)
#define FLEXCAN_FDCTRL_TDCOFF           GENMASK(12, 8)
#define FLEXCAN_FDCTRL_TDCVAL           GENMASK(5, 0)

/* FLEXCAN FD Bit Timing register (FDCBT) bits */
#define FLEXCAN_FDCBT_FPRESDIV_MASK     GENMASK(29, 20)
#define FLEXCAN_FDCBT_FRJW_MASK         GENMASK(18, 16)
#define FLEXCAN_FDCBT_FPROPSEG_MASK     GENMASK(14, 10)
#define FLEXCAN_FDCBT_FPSEG1_MASK       GENMASK(7, 5)
#define FLEXCAN_FDCBT_FPSEG2_MASK       GENMASK(2, 0)

/* FLEXCAN interrupt flag register (IFLAG) bits */
/* Errata ERR005829 step7: Reserve first valid MB */
#define FLEXCAN_TX_MB_RESERVED_RX_FIFO  8
#define FLEXCAN_TX_MB_RESERVED_RX_MAILBOX       0
#define FLEXCAN_RX_MB_RX_MAILBOX_FIRST  (FLEXCAN_TX_MB_RESERVED_RX_MAILBOX + 1)
#define FLEXCAN_IFLAG_MB(x)             BIT_ULL(x)
#define FLEXCAN_IFLAG_RX_FIFO_OVERFLOW  BIT(7)
#define FLEXCAN_IFLAG_RX_FIFO_WARN      BIT(6)
#define FLEXCAN_IFLAG_RX_FIFO_AVAILABLE BIT(5)

/* FLEXCAN message buffers */
#define FLEXCAN_MB_CODE_MASK            (0xf << 24)
#define FLEXCAN_MB_CODE_RX_BUSY_BIT     (0x1 << 24)
#define FLEXCAN_MB_CODE_RX_INACTIVE     (0x0 << 24)
#define FLEXCAN_MB_CODE_RX_EMPTY        (0x4 << 24)
#define FLEXCAN_MB_CODE_RX_FULL         (0x2 << 24)
#define FLEXCAN_MB_CODE_RX_OVERRUN      (0x6 << 24)
#define FLEXCAN_MB_CODE_RX_RANSWER      (0xa << 24)

#define FLEXCAN_MB_CODE_TX_INACTIVE     (0x8 << 24)
#define FLEXCAN_MB_CODE_TX_ABORT        (0x9 << 24)
#define FLEXCAN_MB_CODE_TX_DATA         (0xc << 24)
#define FLEXCAN_MB_CODE_TX_TANSWER      (0xe << 24)

#define FLEXCAN_MB_CNT_EDL              BIT(31)
#define FLEXCAN_MB_CNT_BRS              BIT(30)
#define FLEXCAN_MB_CNT_ESI              BIT(29)
#define FLEXCAN_MB_CNT_SRR              BIT(22)
#define FLEXCAN_MB_CNT_IDE              BIT(21)
#define FLEXCAN_MB_CNT_RTR              BIT(20)
#define FLEXCAN_MB_CNT_LENGTH(x)        (((x) & 0xf) << 16)
#define FLEXCAN_MB_CNT_TIMESTAMP(x)     ((x) & 0xffff)

#define FLEXCAN_TIMEOUT_US              (250)

/* Structure of the message buffer */
struct flexcan_mb {
        u32 can_ctrl;
        u32 can_id;
        u32 data[];
};

/* Structure of the hardware registers */
struct flexcan_regs {
        u32 mcr;                /* 0x00 */
        u32 ctrl;               /* 0x04 - Not affected by Soft Reset */
        u32 timer;              /* 0x08 */
        u32 tcr;                /* 0x0c */
        u32 rxgmask;            /* 0x10 - Not affected by Soft Reset */
        u32 rx14mask;           /* 0x14 - Not affected by Soft Reset */
        u32 rx15mask;           /* 0x18 - Not affected by Soft Reset */
        u32 ecr;                /* 0x1c */
        u32 esr;                /* 0x20 */
        u32 imask2;             /* 0x24 */
        u32 imask1;             /* 0x28 */
        u32 iflag2;             /* 0x2c */
        u32 iflag1;             /* 0x30 */
        union {                 /* 0x34 */
                u32 gfwr_mx28;  /* MX28, MX53 */
                u32 ctrl2;      /* MX6, VF610 - Not affected by Soft Reset */
        };
        u32 esr2;               /* 0x38 */
        u32 imeur;              /* 0x3c */
        u32 lrfr;               /* 0x40 */
        u32 crcr;               /* 0x44 */
        u32 rxfgmask;           /* 0x48 */
        u32 rxfir;              /* 0x4c - Not affected by Soft Reset */
        u32 cbt;                /* 0x50 - Not affected by Soft Reset */
        u32 _reserved2;         /* 0x54 */
        u32 dbg1;               /* 0x58 */
        u32 dbg2;               /* 0x5c */
        u32 _reserved3[8];      /* 0x60 */
        struct_group(init,
                u8 mb[2][512];          /* 0x80 - Not affected by Soft Reset */
                /* FIFO-mode:
                 *                      MB
                 * 0x080...0x08f        0       RX message buffer
                 * 0x090...0x0df        1-5     reserved
                 * 0x0e0...0x0ff        6-7     8 entry ID table
                 *                              (mx25, mx28, mx35, mx53)
                 * 0x0e0...0x2df        6-7..37 8..128 entry ID table
                 *                              size conf'ed via ctrl2::RFFN
                 *                              (mx6, vf610)
                 */
                u32 _reserved4[256];    /* 0x480 */
                u32 rximr[64];          /* 0x880 - Not affected by Soft Reset */
                u32 _reserved5[24];     /* 0x980 */
                u32 gfwr_mx6;           /* 0x9e0 - MX6 */
                u32 _reserved6[39];     /* 0x9e4 */
                u32 _rxfir[6];          /* 0xa80 */
                u32 _reserved8[2];      /* 0xa98 */
                u32 _rxmgmask;          /* 0xaa0 */
                u32 _rxfgmask;          /* 0xaa4 */
                u32 _rx14mask;          /* 0xaa8 */
                u32 _rx15mask;          /* 0xaac */
                u32 tx_smb[4];          /* 0xab0 */
                u32 rx_smb0[4];         /* 0xac0 */
                u32 rx_smb1[4];         /* 0xad0 */
        );
        u32 mecr;               /* 0xae0 */
        u32 erriar;             /* 0xae4 */
        u32 erridpr;            /* 0xae8 */
        u32 errippr;            /* 0xaec */
        u32 rerrar;             /* 0xaf0 */
        u32 rerrdr;             /* 0xaf4 */
        u32 rerrsynr;           /* 0xaf8 */
        u32 errsr;              /* 0xafc */
        u32 _reserved7[64];     /* 0xb00 */
        u32 fdctrl;             /* 0xc00 - Not affected by Soft Reset */
        u32 fdcbt;              /* 0xc04 - Not affected by Soft Reset */
        u32 fdcrc;              /* 0xc08 */
        u32 _reserved9[199];    /* 0xc0c */
        struct_group(init_fd,
                u32 tx_smb_fd[18];      /* 0xf28 */
                u32 rx_smb0_fd[18];     /* 0xf70 */
                u32 rx_smb1_fd[18];     /* 0xfb8 */
        );
};

static_assert(sizeof(struct flexcan_regs) ==  0x4 * 18 + 0xfb8);

static const struct flexcan_devtype_data fsl_mcf5441x_devtype_data = {
        .quirks = FLEXCAN_QUIRK_BROKEN_PERR_STATE |
                FLEXCAN_QUIRK_NR_IRQ_3 | FLEXCAN_QUIRK_NR_MB_16 |
                FLEXCAN_QUIRK_SUPPPORT_RX_MAILBOX |
                FLEXCAN_QUIRK_SUPPPORT_RX_FIFO,
};

static const struct flexcan_devtype_data fsl_p1010_devtype_data = {
        .quirks = FLEXCAN_QUIRK_BROKEN_WERR_STATE |
                FLEXCAN_QUIRK_BROKEN_PERR_STATE |
                FLEXCAN_QUIRK_DEFAULT_BIG_ENDIAN |
                FLEXCAN_QUIRK_SUPPPORT_RX_MAILBOX |
                FLEXCAN_QUIRK_SUPPPORT_RX_FIFO,
};

static const struct flexcan_devtype_data fsl_imx25_devtype_data = {
        .quirks = FLEXCAN_QUIRK_BROKEN_WERR_STATE |
                FLEXCAN_QUIRK_BROKEN_PERR_STATE |
                FLEXCAN_QUIRK_SUPPPORT_RX_MAILBOX |
                FLEXCAN_QUIRK_SUPPPORT_RX_FIFO,
};

static const struct flexcan_devtype_data fsl_imx28_devtype_data = {
        .quirks = FLEXCAN_QUIRK_BROKEN_PERR_STATE |
                FLEXCAN_QUIRK_SUPPPORT_RX_MAILBOX |
                FLEXCAN_QUIRK_SUPPPORT_RX_FIFO,
};

static const struct flexcan_devtype_data fsl_imx6q_devtype_data = {
        .quirks = FLEXCAN_QUIRK_DISABLE_RXFG | FLEXCAN_QUIRK_ENABLE_EACEN_RRS |
                FLEXCAN_QUIRK_USE_RX_MAILBOX | FLEXCAN_QUIRK_BROKEN_PERR_STATE |
                FLEXCAN_QUIRK_SETUP_STOP_MODE_GPR |
                FLEXCAN_QUIRK_SUPPPORT_RX_MAILBOX |
                FLEXCAN_QUIRK_SUPPPORT_RX_MAILBOX_RTR,
};

static const struct flexcan_devtype_data fsl_imx8qm_devtype_data = {
        .quirks = FLEXCAN_QUIRK_DISABLE_RXFG | FLEXCAN_QUIRK_ENABLE_EACEN_RRS |
                FLEXCAN_QUIRK_USE_RX_MAILBOX | FLEXCAN_QUIRK_BROKEN_PERR_STATE |
                FLEXCAN_QUIRK_SUPPORT_FD | FLEXCAN_QUIRK_SETUP_STOP_MODE_SCFW |
                FLEXCAN_QUIRK_SUPPPORT_RX_MAILBOX |
                FLEXCAN_QUIRK_SUPPPORT_RX_MAILBOX_RTR,
};

static struct flexcan_devtype_data fsl_imx8mp_devtype_data = {
        .quirks = FLEXCAN_QUIRK_DISABLE_RXFG | FLEXCAN_QUIRK_ENABLE_EACEN_RRS |
                FLEXCAN_QUIRK_DISABLE_MECR | FLEXCAN_QUIRK_USE_RX_MAILBOX |
                FLEXCAN_QUIRK_BROKEN_PERR_STATE | FLEXCAN_QUIRK_SETUP_STOP_MODE_GPR |
                FLEXCAN_QUIRK_SUPPORT_FD | FLEXCAN_QUIRK_SUPPORT_ECC |
                FLEXCAN_QUIRK_SUPPPORT_RX_MAILBOX |
                FLEXCAN_QUIRK_SUPPPORT_RX_MAILBOX_RTR,
};

static const struct flexcan_devtype_data fsl_vf610_devtype_data = {
        .quirks = FLEXCAN_QUIRK_DISABLE_RXFG | FLEXCAN_QUIRK_ENABLE_EACEN_RRS |
                FLEXCAN_QUIRK_DISABLE_MECR | FLEXCAN_QUIRK_USE_RX_MAILBOX |
                FLEXCAN_QUIRK_BROKEN_PERR_STATE | FLEXCAN_QUIRK_SUPPORT_ECC |
                FLEXCAN_QUIRK_SUPPPORT_RX_MAILBOX |
                FLEXCAN_QUIRK_SUPPPORT_RX_MAILBOX_RTR,
};

static const struct flexcan_devtype_data fsl_ls1021a_r2_devtype_data = {
        .quirks = FLEXCAN_QUIRK_DISABLE_RXFG | FLEXCAN_QUIRK_ENABLE_EACEN_RRS |
                FLEXCAN_QUIRK_BROKEN_PERR_STATE | FLEXCAN_QUIRK_USE_RX_MAILBOX |
                FLEXCAN_QUIRK_SUPPPORT_RX_MAILBOX |
                FLEXCAN_QUIRK_SUPPPORT_RX_MAILBOX_RTR,
};

static const struct flexcan_devtype_data fsl_lx2160a_r1_devtype_data = {
        .quirks = FLEXCAN_QUIRK_DISABLE_RXFG | FLEXCAN_QUIRK_ENABLE_EACEN_RRS |
                FLEXCAN_QUIRK_DISABLE_MECR | FLEXCAN_QUIRK_BROKEN_PERR_STATE |
                FLEXCAN_QUIRK_USE_RX_MAILBOX | FLEXCAN_QUIRK_SUPPORT_FD |
                FLEXCAN_QUIRK_SUPPORT_ECC |
                FLEXCAN_QUIRK_SUPPPORT_RX_MAILBOX |
                FLEXCAN_QUIRK_SUPPPORT_RX_MAILBOX_RTR,
};

static const struct can_bittiming_const flexcan_bittiming_const = {
        .name = DRV_NAME,
        .tseg1_min = 4,
        .tseg1_max = 16,
        .tseg2_min = 2,
        .tseg2_max = 8,
        .sjw_max = 4,
        .brp_min = 1,
        .brp_max = 256,
        .brp_inc = 1,
};

static const struct can_bittiming_const flexcan_fd_bittiming_const = {
        .name = DRV_NAME,
        .tseg1_min = 2,
        .tseg1_max = 96,
        .tseg2_min = 2,
        .tseg2_max = 32,
        .sjw_max = 16,
        .brp_min = 1,
        .brp_max = 1024,
        .brp_inc = 1,
};

static const struct can_bittiming_const flexcan_fd_data_bittiming_const = {
        .name = DRV_NAME,
        .tseg1_min = 2,
        .tseg1_max = 39,
        .tseg2_min = 2,
        .tseg2_max = 8,
        .sjw_max = 4,
        .brp_min = 1,
        .brp_max = 1024,
        .brp_inc = 1,
};

/* FlexCAN module is essentially modelled as a little-endian IP in most
 * SoCs, i.e the registers as well as the message buffer areas are
 * implemented in a little-endian fashion.
 *
 * However there are some SoCs (e.g. LS1021A) which implement the FlexCAN
 * module in a big-endian fashion (i.e the registers as well as the
 * message buffer areas are implemented in a big-endian way).
 *
 * In addition, the FlexCAN module can be found on SoCs having ARM or
 * PPC cores. So, we need to abstract off the register read/write
 * functions, ensuring that these cater to all the combinations of module
 * endianness and underlying CPU endianness.
 */
static inline u32 flexcan_read_be(void __iomem *addr)
{
        return ioread32be(addr);
}

static inline void flexcan_write_be(u32 val, void __iomem *addr)
{
        iowrite32be(val, addr);
}

static inline u32 flexcan_read_le(void __iomem *addr)
{
        return ioread32(addr);
}

static inline void flexcan_write_le(u32 val, void __iomem *addr)
{
        iowrite32(val, addr);
}

static struct flexcan_mb __iomem *flexcan_get_mb(const struct flexcan_priv *priv,
                                                 u8 mb_index)
{
        u8 bank_size;
        bool bank;

        if (WARN_ON(mb_index >= priv->mb_count))
                return NULL;

        bank_size = sizeof(priv->regs->mb[0]) / priv->mb_size;

        bank = mb_index >= bank_size;
        if (bank)
                mb_index -= bank_size;

        return (struct flexcan_mb __iomem *)
                (&priv->regs->mb[bank][priv->mb_size * mb_index]);
}

static int flexcan_low_power_enter_ack(struct flexcan_priv *priv)
{
        struct flexcan_regs __iomem *regs = priv->regs;
        unsigned int timeout = FLEXCAN_TIMEOUT_US / 10;

        while (timeout-- && !(priv->read(&regs->mcr) & FLEXCAN_MCR_LPM_ACK))
                udelay(10);

        if (!(priv->read(&regs->mcr) & FLEXCAN_MCR_LPM_ACK))
                return -ETIMEDOUT;

        return 0;
}

static int flexcan_low_power_exit_ack(struct flexcan_priv *priv)
{
        struct flexcan_regs __iomem *regs = priv->regs;
        unsigned int timeout = FLEXCAN_TIMEOUT_US / 10;

        while (timeout-- && (priv->read(&regs->mcr) & FLEXCAN_MCR_LPM_ACK))
                udelay(10);

        if (priv->read(&regs->mcr) & FLEXCAN_MCR_LPM_ACK)
                return -ETIMEDOUT;

        return 0;
}

static void flexcan_enable_wakeup_irq(struct flexcan_priv *priv, bool enable)
{
        struct flexcan_regs __iomem *regs = priv->regs;
        u32 reg_mcr;

        reg_mcr = priv->read(&regs->mcr);

        if (enable)
                reg_mcr |= FLEXCAN_MCR_WAK_MSK;
        else
                reg_mcr &= ~FLEXCAN_MCR_WAK_MSK;

        priv->write(reg_mcr, &regs->mcr);
}

static int flexcan_stop_mode_enable_scfw(struct flexcan_priv *priv, bool enabled)
{
        u8 idx = priv->scu_idx;
        u32 rsrc_id, val;

        rsrc_id = IMX_SC_R_CAN(idx);

        if (enabled)
                val = 1;
        else
                val = 0;

        /* stop mode request via scu firmware */
        return imx_sc_misc_set_control(priv->sc_ipc_handle, rsrc_id,
                                       IMX_SC_C_IPG_STOP, val);
}

static inline int flexcan_enter_stop_mode(struct flexcan_priv *priv)
{
        struct flexcan_regs __iomem *regs = priv->regs;
        u32 reg_mcr;
        int ret;

        reg_mcr = priv->read(&regs->mcr);
        reg_mcr |= FLEXCAN_MCR_SLF_WAK;
        priv->write(reg_mcr, &regs->mcr);

        /* enable stop request */
        if (priv->devtype_data.quirks & FLEXCAN_QUIRK_SETUP_STOP_MODE_SCFW) {
                ret = flexcan_stop_mode_enable_scfw(priv, true);
                if (ret < 0)
                        return ret;
        } else {
                regmap_update_bits(priv->stm.gpr, priv->stm.req_gpr,
                                   1 << priv->stm.req_bit, 1 << priv->stm.req_bit);
        }

        return flexcan_low_power_enter_ack(priv);
}

static inline int flexcan_exit_stop_mode(struct flexcan_priv *priv)
{
        struct flexcan_regs __iomem *regs = priv->regs;
        u32 reg_mcr;
        int ret;

        /* remove stop request */
        if (priv->devtype_data.quirks & FLEXCAN_QUIRK_SETUP_STOP_MODE_SCFW) {
                ret = flexcan_stop_mode_enable_scfw(priv, false);
                if (ret < 0)
                        return ret;
        } else {
                regmap_update_bits(priv->stm.gpr, priv->stm.req_gpr,
                                   1 << priv->stm.req_bit, 0);
        }

        reg_mcr = priv->read(&regs->mcr);
        reg_mcr &= ~FLEXCAN_MCR_SLF_WAK;
        priv->write(reg_mcr, &regs->mcr);

        return flexcan_low_power_exit_ack(priv);
}

static inline void flexcan_error_irq_enable(const struct flexcan_priv *priv)
{
        struct flexcan_regs __iomem *regs = priv->regs;
        u32 reg_ctrl = (priv->reg_ctrl_default | FLEXCAN_CTRL_ERR_MSK);

        priv->write(reg_ctrl, &regs->ctrl);
}

static inline void flexcan_error_irq_disable(const struct flexcan_priv *priv)
{
        struct flexcan_regs __iomem *regs = priv->regs;
        u32 reg_ctrl = (priv->reg_ctrl_default & ~FLEXCAN_CTRL_ERR_MSK);

        priv->write(reg_ctrl, &regs->ctrl);
}

static int flexcan_clks_enable(const struct flexcan_priv *priv)
{
        int err = 0;

        if (priv->clk_ipg) {
                err = clk_prepare_enable(priv->clk_ipg);
                if (err)
                        return err;
        }

        if (priv->clk_per) {
                err = clk_prepare_enable(priv->clk_per);
                if (err)
                        clk_disable_unprepare(priv->clk_ipg);
        }

        return err;
}

static void flexcan_clks_disable(const struct flexcan_priv *priv)
{
        clk_disable_unprepare(priv->clk_per);
        clk_disable_unprepare(priv->clk_ipg);
}

static inline int flexcan_transceiver_enable(const struct flexcan_priv *priv)
{
        if (!priv->reg_xceiver)
                return 0;

        return regulator_enable(priv->reg_xceiver);
}

static inline int flexcan_transceiver_disable(const struct flexcan_priv *priv)
{
        if (!priv->reg_xceiver)
                return 0;

        return regulator_disable(priv->reg_xceiver);
}

static int flexcan_chip_enable(struct flexcan_priv *priv)
{
        struct flexcan_regs __iomem *regs = priv->regs;
        u32 reg;

        reg = priv->read(&regs->mcr);
        reg &= ~FLEXCAN_MCR_MDIS;
        priv->write(reg, &regs->mcr);

        return flexcan_low_power_exit_ack(priv);
}

static int flexcan_chip_disable(struct flexcan_priv *priv)
{
        struct flexcan_regs __iomem *regs = priv->regs;
        u32 reg;

        reg = priv->read(&regs->mcr);
        reg |= FLEXCAN_MCR_MDIS;
        priv->write(reg, &regs->mcr);

        return flexcan_low_power_enter_ack(priv);
}

static int flexcan_chip_freeze(struct flexcan_priv *priv)
{
        struct flexcan_regs __iomem *regs = priv->regs;
        unsigned int timeout;
        u32 bitrate = priv->can.bittiming.bitrate;
        u32 reg;

        if (bitrate)
                timeout = 1000 * 1000 * 10 / bitrate;
        else
                timeout = FLEXCAN_TIMEOUT_US / 10;

        reg = priv->read(&regs->mcr);
        reg |= FLEXCAN_MCR_FRZ | FLEXCAN_MCR_HALT;
        priv->write(reg, &regs->mcr);

        while (timeout-- && !(priv->read(&regs->mcr) & FLEXCAN_MCR_FRZ_ACK))
                udelay(100);

        if (!(priv->read(&regs->mcr) & FLEXCAN_MCR_FRZ_ACK))
                return -ETIMEDOUT;

        return 0;
}

static int flexcan_chip_unfreeze(struct flexcan_priv *priv)
{
        struct flexcan_regs __iomem *regs = priv->regs;
        unsigned int timeout = FLEXCAN_TIMEOUT_US / 10;
        u32 reg;

        reg = priv->read(&regs->mcr);
        reg &= ~FLEXCAN_MCR_HALT;
        priv->write(reg, &regs->mcr);

        while (timeout-- && (priv->read(&regs->mcr) & FLEXCAN_MCR_FRZ_ACK))
                udelay(10);

        if (priv->read(&regs->mcr) & FLEXCAN_MCR_FRZ_ACK)
                return -ETIMEDOUT;

        return 0;
}

static int flexcan_chip_softreset(struct flexcan_priv *priv)
{
        struct flexcan_regs __iomem *regs = priv->regs;
        unsigned int timeout = FLEXCAN_TIMEOUT_US / 10;

        priv->write(FLEXCAN_MCR_SOFTRST, &regs->mcr);
        while (timeout-- && (priv->read(&regs->mcr) & FLEXCAN_MCR_SOFTRST))
                udelay(10);

        if (priv->read(&regs->mcr) & FLEXCAN_MCR_SOFTRST)
                return -ETIMEDOUT;

        return 0;
}

static int __flexcan_get_berr_counter(const struct net_device *dev,
                                      struct can_berr_counter *bec)
{
        const struct flexcan_priv *priv = netdev_priv(dev);
        struct flexcan_regs __iomem *regs = priv->regs;
        u32 reg = priv->read(&regs->ecr);

        bec->txerr = (reg >> 0) & 0xff;
        bec->rxerr = (reg >> 8) & 0xff;

        return 0;
}

static int flexcan_get_berr_counter(const struct net_device *dev,
                                    struct can_berr_counter *bec)
{
        const struct flexcan_priv *priv = netdev_priv(dev);
        int err;

        err = pm_runtime_get_sync(priv->dev);
        if (err < 0) {
                pm_runtime_put_noidle(priv->dev);
                return err;
        }

        err = __flexcan_get_berr_counter(dev, bec);

        pm_runtime_put(priv->dev);

        return err;
}

static netdev_tx_t flexcan_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
        const struct flexcan_priv *priv = netdev_priv(dev);
        struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
        u32 can_id;
        u32 data;
        u32 ctrl = FLEXCAN_MB_CODE_TX_DATA | ((can_fd_len2dlc(cfd->len)) << 16);
        int i;

        if (can_dropped_invalid_skb(dev, skb))
                return NETDEV_TX_OK;

        netif_stop_queue(dev);

        if (cfd->can_id & CAN_EFF_FLAG) {
                can_id = cfd->can_id & CAN_EFF_MASK;
                ctrl |= FLEXCAN_MB_CNT_IDE | FLEXCAN_MB_CNT_SRR;
        } else {
                can_id = (cfd->can_id & CAN_SFF_MASK) << 18;
        }

        if (cfd->can_id & CAN_RTR_FLAG)
                ctrl |= FLEXCAN_MB_CNT_RTR;

        if (can_is_canfd_skb(skb)) {
                ctrl |= FLEXCAN_MB_CNT_EDL;

                if (cfd->flags & CANFD_BRS)
                        ctrl |= FLEXCAN_MB_CNT_BRS;
        }

        for (i = 0; i < cfd->len; i += sizeof(u32)) {
                data = be32_to_cpup((__be32 *)&cfd->data[i]);
                priv->write(data, &priv->tx_mb->data[i / sizeof(u32)]);
        }

        can_put_echo_skb(skb, dev, 0, 0);

        priv->write(can_id, &priv->tx_mb->can_id);
        priv->write(ctrl, &priv->tx_mb->can_ctrl);

        /* Errata ERR005829 step8:
         * Write twice INACTIVE(0x8) code to first MB.
         */
        priv->write(FLEXCAN_MB_CODE_TX_INACTIVE,
                    &priv->tx_mb_reserved->can_ctrl);
        priv->write(FLEXCAN_MB_CODE_TX_INACTIVE,
                    &priv->tx_mb_reserved->can_ctrl);

        return NETDEV_TX_OK;
}

static void flexcan_irq_bus_err(struct net_device *dev, u32 reg_esr)
{
        struct flexcan_priv *priv = netdev_priv(dev);
        struct flexcan_regs __iomem *regs = priv->regs;
        struct sk_buff *skb;
        struct can_frame *cf;
        bool rx_errors = false, tx_errors = false;
        u32 timestamp;
        int err;

        timestamp = priv->read(&regs->timer) << 16;

        skb = alloc_can_err_skb(dev, &cf);
        if (unlikely(!skb))
                return;

        cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;

        if (reg_esr & FLEXCAN_ESR_BIT1_ERR) {
                netdev_dbg(dev, "BIT1_ERR irq\n");
                cf->data[2] |= CAN_ERR_PROT_BIT1;
                tx_errors = true;
        }
        if (reg_esr & FLEXCAN_ESR_BIT0_ERR) {
                netdev_dbg(dev, "BIT0_ERR irq\n");
                cf->data[2] |= CAN_ERR_PROT_BIT0;
                tx_errors = true;
        }
        if (reg_esr & FLEXCAN_ESR_ACK_ERR) {
                netdev_dbg(dev, "ACK_ERR irq\n");
                cf->can_id |= CAN_ERR_ACK;
                cf->data[3] = CAN_ERR_PROT_LOC_ACK;
                tx_errors = true;
        }
        if (reg_esr & FLEXCAN_ESR_CRC_ERR) {
                netdev_dbg(dev, "CRC_ERR irq\n");
                cf->data[2] |= CAN_ERR_PROT_BIT;
                cf->data[3] = CAN_ERR_PROT_LOC_CRC_SEQ;
                rx_errors = true;
        }
        if (reg_esr & FLEXCAN_ESR_FRM_ERR) {
                netdev_dbg(dev, "FRM_ERR irq\n");
                cf->data[2] |= CAN_ERR_PROT_FORM;
                rx_errors = true;
        }
        if (reg_esr & FLEXCAN_ESR_STF_ERR) {
                netdev_dbg(dev, "STF_ERR irq\n");
                cf->data[2] |= CAN_ERR_PROT_STUFF;
                rx_errors = true;
        }

        priv->can.can_stats.bus_error++;
        if (rx_errors)
                dev->stats.rx_errors++;
        if (tx_errors)
                dev->stats.tx_errors++;

        err = can_rx_offload_queue_sorted(&priv->offload, skb, timestamp);
        if (err)
                dev->stats.rx_fifo_errors++;
}

static void flexcan_irq_state(struct net_device *dev, u32 reg_esr)
{
        struct flexcan_priv *priv = netdev_priv(dev);
        struct flexcan_regs __iomem *regs = priv->regs;
        struct sk_buff *skb;
        struct can_frame *cf;
        enum can_state new_state, rx_state, tx_state;
        int flt;
        struct can_berr_counter bec;
        u32 timestamp;
        int err;

        flt = reg_esr & FLEXCAN_ESR_FLT_CONF_MASK;
        if (likely(flt == FLEXCAN_ESR_FLT_CONF_ACTIVE)) {
                tx_state = unlikely(reg_esr & FLEXCAN_ESR_TX_WRN) ?
                        CAN_STATE_ERROR_WARNING : CAN_STATE_ERROR_ACTIVE;
                rx_state = unlikely(reg_esr & FLEXCAN_ESR_RX_WRN) ?
                        CAN_STATE_ERROR_WARNING : CAN_STATE_ERROR_ACTIVE;
                new_state = max(tx_state, rx_state);
        } else {
                __flexcan_get_berr_counter(dev, &bec);
                new_state = flt == FLEXCAN_ESR_FLT_CONF_PASSIVE ?
                        CAN_STATE_ERROR_PASSIVE : CAN_STATE_BUS_OFF;
                rx_state = bec.rxerr >= bec.txerr ? new_state : 0;
                tx_state = bec.rxerr <= bec.txerr ? new_state : 0;
        }

        /* state hasn't changed */
        if (likely(new_state == priv->can.state))
                return;

        timestamp = priv->read(&regs->timer) << 16;

        skb = alloc_can_err_skb(dev, &cf);
        if (unlikely(!skb))
                return;

        can_change_state(dev, cf, tx_state, rx_state);

        if (unlikely(new_state == CAN_STATE_BUS_OFF))
                can_bus_off(dev);

        err = can_rx_offload_queue_sorted(&priv->offload, skb, timestamp);
        if (err)
                dev->stats.rx_fifo_errors++;
}

static inline u64 flexcan_read64_mask(struct flexcan_priv *priv, void __iomem *addr, u64 mask)
{
        u64 reg = 0;

        if (upper_32_bits(mask))
                reg = (u64)priv->read(addr - 4) << 32;
        if (lower_32_bits(mask))
                reg |= priv->read(addr);

        return reg & mask;
}

static inline void flexcan_write64(struct flexcan_priv *priv, u64 val, void __iomem *addr)
{
        if (upper_32_bits(val))
                priv->write(upper_32_bits(val), addr - 4);
        if (lower_32_bits(val))
                priv->write(lower_32_bits(val), addr);
}

static inline u64 flexcan_read_reg_iflag_rx(struct flexcan_priv *priv)
{
        return flexcan_read64_mask(priv, &priv->regs->iflag1, priv->rx_mask);
}

static inline u64 flexcan_read_reg_iflag_tx(struct flexcan_priv *priv)
{
        return flexcan_read64_mask(priv, &priv->regs->iflag1, priv->tx_mask);
}

static inline struct flexcan_priv *rx_offload_to_priv(struct can_rx_offload *offload)
{
        return container_of(offload, struct flexcan_priv, offload);
}

static struct sk_buff *flexcan_mailbox_read(struct can_rx_offload *offload,
                                            unsigned int n, u32 *timestamp,
                                            bool drop)
{
        struct flexcan_priv *priv = rx_offload_to_priv(offload);
        struct flexcan_regs __iomem *regs = priv->regs;
        struct flexcan_mb __iomem *mb;
        struct sk_buff *skb;
        struct canfd_frame *cfd;
        u32 reg_ctrl, reg_id, reg_iflag1;
        int i;

        if (unlikely(drop)) {
                skb = ERR_PTR(-ENOBUFS);
                goto mark_as_read;
        }

        mb = flexcan_get_mb(priv, n);

        if (priv->devtype_data.quirks & FLEXCAN_QUIRK_USE_RX_MAILBOX) {
                u32 code;

                do {
                        reg_ctrl = priv->read(&mb->can_ctrl);
                } while (reg_ctrl & FLEXCAN_MB_CODE_RX_BUSY_BIT);

                /* is this MB empty? */
                code = reg_ctrl & FLEXCAN_MB_CODE_MASK;
                if ((code != FLEXCAN_MB_CODE_RX_FULL) &&
                    (code != FLEXCAN_MB_CODE_RX_OVERRUN))
                        return NULL;

                if (code == FLEXCAN_MB_CODE_RX_OVERRUN) {
                        /* This MB was overrun, we lost data */
                        offload->dev->stats.rx_over_errors++;
                        offload->dev->stats.rx_errors++;
                }
        } else {
                reg_iflag1 = priv->read(&regs->iflag1);
                if (!(reg_iflag1 & FLEXCAN_IFLAG_RX_FIFO_AVAILABLE))
                        return NULL;

                reg_ctrl = priv->read(&mb->can_ctrl);
        }

        if (reg_ctrl & FLEXCAN_MB_CNT_EDL)
                skb = alloc_canfd_skb(offload->dev, &cfd);
        else
                skb = alloc_can_skb(offload->dev, (struct can_frame **)&cfd);
        if (unlikely(!skb)) {
                skb = ERR_PTR(-ENOMEM);
                goto mark_as_read;
        }

        /* increase timstamp to full 32 bit */
        *timestamp = reg_ctrl << 16;

        reg_id = priv->read(&mb->can_id);
        if (reg_ctrl & FLEXCAN_MB_CNT_IDE)
                cfd->can_id = ((reg_id >> 0) & CAN_EFF_MASK) | CAN_EFF_FLAG;
        else
                cfd->can_id = (reg_id >> 18) & CAN_SFF_MASK;

        if (reg_ctrl & FLEXCAN_MB_CNT_EDL) {
                cfd->len = can_fd_dlc2len((reg_ctrl >> 16) & 0xf);

                if (reg_ctrl & FLEXCAN_MB_CNT_BRS)
                        cfd->flags |= CANFD_BRS;
        } else {
                cfd->len = can_cc_dlc2len((reg_ctrl >> 16) & 0xf);

                if (reg_ctrl & FLEXCAN_MB_CNT_RTR)
                        cfd->can_id |= CAN_RTR_FLAG;
        }

        if (reg_ctrl & FLEXCAN_MB_CNT_ESI)
                cfd->flags |= CANFD_ESI;

        for (i = 0; i < cfd->len; i += sizeof(u32)) {
                __be32 data = cpu_to_be32(priv->read(&mb->data[i / sizeof(u32)]));
                *(__be32 *)(cfd->data + i) = data;
        }

 mark_as_read:
        if (priv->devtype_data.quirks & FLEXCAN_QUIRK_USE_RX_MAILBOX)
                flexcan_write64(priv, FLEXCAN_IFLAG_MB(n), &regs->iflag1);
        else
                priv->write(FLEXCAN_IFLAG_RX_FIFO_AVAILABLE, &regs->iflag1);

        /* Read the Free Running Timer. It is optional but recommended
         * to unlock Mailbox as soon as possible and make it available
         * for reception.
         */
        priv->read(&regs->timer);

        return skb;
}

static irqreturn_t flexcan_irq(int irq, void *dev_id)
{
        struct net_device *dev = dev_id;
        struct net_device_stats *stats = &dev->stats;
        struct flexcan_priv *priv = netdev_priv(dev);
        struct flexcan_regs __iomem *regs = priv->regs;
        irqreturn_t handled = IRQ_NONE;
        u64 reg_iflag_tx;
        u32 reg_esr;
        enum can_state last_state = priv->can.state;

        /* reception interrupt */
        if (priv->devtype_data.quirks & FLEXCAN_QUIRK_USE_RX_MAILBOX) {
                u64 reg_iflag_rx;
                int ret;

                while ((reg_iflag_rx = flexcan_read_reg_iflag_rx(priv))) {
                        handled = IRQ_HANDLED;
                        ret = can_rx_offload_irq_offload_timestamp(&priv->offload,
                                                                   reg_iflag_rx);
                        if (!ret)
                                break;
                }
        } else {
                u32 reg_iflag1;

                reg_iflag1 = priv->read(&regs->iflag1);
                if (reg_iflag1 & FLEXCAN_IFLAG_RX_FIFO_AVAILABLE) {
                        handled = IRQ_HANDLED;
                        can_rx_offload_irq_offload_fifo(&priv->offload);
                }

                /* FIFO overflow interrupt */
                if (reg_iflag1 & FLEXCAN_IFLAG_RX_FIFO_OVERFLOW) {
                        handled = IRQ_HANDLED;
                        priv->write(FLEXCAN_IFLAG_RX_FIFO_OVERFLOW,
                                    &regs->iflag1);
                        dev->stats.rx_over_errors++;
                        dev->stats.rx_errors++;
                }
        }

        reg_iflag_tx = flexcan_read_reg_iflag_tx(priv);

        /* transmission complete interrupt */
        if (reg_iflag_tx & priv->tx_mask) {
                u32 reg_ctrl = priv->read(&priv->tx_mb->can_ctrl);

                handled = IRQ_HANDLED;
                stats->tx_bytes +=
                        can_rx_offload_get_echo_skb(&priv->offload, 0,
                                                    reg_ctrl << 16, NULL);
                stats->tx_packets++;
                can_led_event(dev, CAN_LED_EVENT_TX);

                /* after sending a RTR frame MB is in RX mode */
                priv->write(FLEXCAN_MB_CODE_TX_INACTIVE,
                            &priv->tx_mb->can_ctrl);
                flexcan_write64(priv, priv->tx_mask, &regs->iflag1);
                netif_wake_queue(dev);
        }

        reg_esr = priv->read(&regs->esr);

        /* ACK all bus error, state change and wake IRQ sources */
        if (reg_esr & (FLEXCAN_ESR_ALL_INT | FLEXCAN_ESR_WAK_INT)) {
                handled = IRQ_HANDLED;
                priv->write(reg_esr & (FLEXCAN_ESR_ALL_INT | FLEXCAN_ESR_WAK_INT), &regs->esr);
        }

        /* state change interrupt or broken error state quirk fix is enabled */
        if ((reg_esr & FLEXCAN_ESR_ERR_STATE) ||
            (priv->devtype_data.quirks & (FLEXCAN_QUIRK_BROKEN_WERR_STATE |
                                           FLEXCAN_QUIRK_BROKEN_PERR_STATE)))
                flexcan_irq_state(dev, reg_esr);

        /* bus error IRQ - handle if bus error reporting is activated */
        if ((reg_esr & FLEXCAN_ESR_ERR_BUS) &&
            (priv->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING))
                flexcan_irq_bus_err(dev, reg_esr);

        /* availability of error interrupt among state transitions in case
         * bus error reporting is de-activated and
         * FLEXCAN_QUIRK_BROKEN_PERR_STATE is enabled:
         *  +--------------------------------------------------------------+
         *  | +----------------------------------------------+ [stopped /  |
         *  | |                                              |  sleeping] -+
         *  +-+-> active <-> warning <-> passive -> bus off -+
         *        ___________^^^^^^^^^^^^_______________________________
         *        disabled(1)  enabled             disabled
         *
         * (1): enabled if FLEXCAN_QUIRK_BROKEN_WERR_STATE is enabled
         */
        if ((last_state != priv->can.state) &&
            (priv->devtype_data.quirks & FLEXCAN_QUIRK_BROKEN_PERR_STATE) &&
            !(priv->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING)) {
                switch (priv->can.state) {
                case CAN_STATE_ERROR_ACTIVE:
                        if (priv->devtype_data.quirks &
                            FLEXCAN_QUIRK_BROKEN_WERR_STATE)
                                flexcan_error_irq_enable(priv);
                        else
                                flexcan_error_irq_disable(priv);
                        break;

                case CAN_STATE_ERROR_WARNING:
                        flexcan_error_irq_enable(priv);
                        break;

                case CAN_STATE_ERROR_PASSIVE:
                case CAN_STATE_BUS_OFF:
                        flexcan_error_irq_disable(priv);
                        break;

                default:
                        break;
                }
        }

        if (handled)
                can_rx_offload_irq_finish(&priv->offload);

        return handled;
}

static void flexcan_set_bittiming_ctrl(const struct net_device *dev)
{
        const struct flexcan_priv *priv = netdev_priv(dev);
        const struct can_bittiming *bt = &priv->can.bittiming;
        struct flexcan_regs __iomem *regs = priv->regs;
        u32 reg;

        reg = priv->read(&regs->ctrl);
        reg &= ~(FLEXCAN_CTRL_PRESDIV(0xff) |
                 FLEXCAN_CTRL_RJW(0x3) |
                 FLEXCAN_CTRL_PSEG1(0x7) |
                 FLEXCAN_CTRL_PSEG2(0x7) |
                 FLEXCAN_CTRL_PROPSEG(0x7));

        reg |= FLEXCAN_CTRL_PRESDIV(bt->brp - 1) |
                FLEXCAN_CTRL_PSEG1(bt->phase_seg1 - 1) |
                FLEXCAN_CTRL_PSEG2(bt->phase_seg2 - 1) |
                FLEXCAN_CTRL_RJW(bt->sjw - 1) |
                FLEXCAN_CTRL_PROPSEG(bt->prop_seg - 1);

        netdev_dbg(dev, "writing ctrl=0x%08x\n", reg);
        priv->write(reg, &regs->ctrl);

        /* print chip status */
        netdev_dbg(dev, "%s: mcr=0x%08x ctrl=0x%08x\n", __func__,
                   priv->read(&regs->mcr), priv->read(&regs->ctrl));
}

static void flexcan_set_bittiming_cbt(const struct net_device *dev)
{
        struct flexcan_priv *priv = netdev_priv(dev);
        struct can_bittiming *bt = &priv->can.bittiming;
        struct can_bittiming *dbt = &priv->can.data_bittiming;
        struct flexcan_regs __iomem *regs = priv->regs;
        u32 reg_cbt, reg_fdctrl;

        /* CBT */
        /* CBT[EPSEG1] is 5 bit long and CBT[EPROPSEG] is 6 bit
         * long. The can_calc_bittiming() tries to divide the tseg1
         * equally between phase_seg1 and prop_seg, which may not fit
         * in CBT register. Therefore, if phase_seg1 is more than
         * possible value, increase prop_seg and decrease phase_seg1.
         */
        if (bt->phase_seg1 > 0x20) {
                bt->prop_seg += (bt->phase_seg1 - 0x20);
                bt->phase_seg1 = 0x20;
        }

        reg_cbt = FLEXCAN_CBT_BTF |
                FIELD_PREP(FLEXCAN_CBT_EPRESDIV_MASK, bt->brp - 1) |
                FIELD_PREP(FLEXCAN_CBT_ERJW_MASK, bt->sjw - 1) |
                FIELD_PREP(FLEXCAN_CBT_EPROPSEG_MASK, bt->prop_seg - 1) |
                FIELD_PREP(FLEXCAN_CBT_EPSEG1_MASK, bt->phase_seg1 - 1) |
                FIELD_PREP(FLEXCAN_CBT_EPSEG2_MASK, bt->phase_seg2 - 1);

        netdev_dbg(dev, "writing cbt=0x%08x\n", reg_cbt);
        priv->write(reg_cbt, &regs->cbt);

        if (priv->can.ctrlmode & CAN_CTRLMODE_FD) {
                u32 reg_fdcbt, reg_ctrl2;

                if (bt->brp != dbt->brp)
                        netdev_warn(dev, "Data brp=%d and brp=%d don't match, this may result in a phase error. Consider using different bitrate and/or data bitrate.\n",
                                    dbt->brp, bt->brp);

                /* FDCBT */
                /* FDCBT[FPSEG1] is 3 bit long and FDCBT[FPROPSEG] is
                 * 5 bit long. The can_calc_bittiming tries to divide
                 * the tseg1 equally between phase_seg1 and prop_seg,
                 * which may not fit in FDCBT register. Therefore, if
                 * phase_seg1 is more than possible value, increase
                 * prop_seg and decrease phase_seg1
                 */
                if (dbt->phase_seg1 > 0x8) {
                        dbt->prop_seg += (dbt->phase_seg1 - 0x8);
                        dbt->phase_seg1 = 0x8;
                }

                reg_fdcbt = priv->read(&regs->fdcbt);
                reg_fdcbt &= ~(FIELD_PREP(FLEXCAN_FDCBT_FPRESDIV_MASK, 0x3ff) |
                               FIELD_PREP(FLEXCAN_FDCBT_FRJW_MASK, 0x7) |
                               FIELD_PREP(FLEXCAN_FDCBT_FPROPSEG_MASK, 0x1f) |
                               FIELD_PREP(FLEXCAN_FDCBT_FPSEG1_MASK, 0x7) |
                               FIELD_PREP(FLEXCAN_FDCBT_FPSEG2_MASK, 0x7));

                reg_fdcbt |= FIELD_PREP(FLEXCAN_FDCBT_FPRESDIV_MASK, dbt->brp - 1) |
                        FIELD_PREP(FLEXCAN_FDCBT_FRJW_MASK, dbt->sjw - 1) |
                        FIELD_PREP(FLEXCAN_FDCBT_FPROPSEG_MASK, dbt->prop_seg) |
                        FIELD_PREP(FLEXCAN_FDCBT_FPSEG1_MASK, dbt->phase_seg1 - 1) |
                        FIELD_PREP(FLEXCAN_FDCBT_FPSEG2_MASK, dbt->phase_seg2 - 1);

                netdev_dbg(dev, "writing fdcbt=0x%08x\n", reg_fdcbt);
                priv->write(reg_fdcbt, &regs->fdcbt);

                /* CTRL2 */
                reg_ctrl2 = priv->read(&regs->ctrl2);
                reg_ctrl2 &= ~FLEXCAN_CTRL2_ISOCANFDEN;
                if (!(priv->can.ctrlmode & CAN_CTRLMODE_FD_NON_ISO))
                        reg_ctrl2 |= FLEXCAN_CTRL2_ISOCANFDEN;

                netdev_dbg(dev, "writing ctrl2=0x%08x\n", reg_ctrl2);
                priv->write(reg_ctrl2, &regs->ctrl2);
        }

        /* FDCTRL */
        reg_fdctrl = priv->read(&regs->fdctrl);
        reg_fdctrl &= ~(FLEXCAN_FDCTRL_FDRATE |
                        FIELD_PREP(FLEXCAN_FDCTRL_TDCOFF, 0x1f));

        if (priv->can.ctrlmode & CAN_CTRLMODE_FD) {
                reg_fdctrl |= FLEXCAN_FDCTRL_FDRATE;

                if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK) {
                        /* TDC must be disabled for Loop Back mode */
                        reg_fdctrl &= ~FLEXCAN_FDCTRL_TDCEN;
                } else {
                        reg_fdctrl |= FLEXCAN_FDCTRL_TDCEN |
                                FIELD_PREP(FLEXCAN_FDCTRL_TDCOFF,
                                           ((dbt->phase_seg1 - 1) +
                                            dbt->prop_seg + 2) *
                                           ((dbt->brp - 1 ) + 1));
                }
        }

        netdev_dbg(dev, "writing fdctrl=0x%08x\n", reg_fdctrl);
        priv->write(reg_fdctrl, &regs->fdctrl);

        netdev_dbg(dev, "%s: mcr=0x%08x ctrl=0x%08x ctrl2=0x%08x fdctrl=0x%08x cbt=0x%08x fdcbt=0x%08x\n",
                   __func__,
                   priv->read(&regs->mcr), priv->read(&regs->ctrl),
                   priv->read(&regs->ctrl2), priv->read(&regs->fdctrl),
                   priv->read(&regs->cbt), priv->read(&regs->fdcbt));
}

static void flexcan_set_bittiming(struct net_device *dev)
{
        const struct flexcan_priv *priv = netdev_priv(dev);
        struct flexcan_regs __iomem *regs = priv->regs;
        u32 reg;

        reg = priv->read(&regs->ctrl);
        reg &= ~(FLEXCAN_CTRL_LPB | FLEXCAN_CTRL_SMP |
                 FLEXCAN_CTRL_LOM);

        if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK)
                reg |= FLEXCAN_CTRL_LPB;
        if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
                reg |= FLEXCAN_CTRL_LOM;
        if (priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES)
                reg |= FLEXCAN_CTRL_SMP;

        netdev_dbg(dev, "writing ctrl=0x%08x\n", reg);
        priv->write(reg, &regs->ctrl);

        if (priv->can.ctrlmode_supported & CAN_CTRLMODE_FD)
                return flexcan_set_bittiming_cbt(dev);
        else
                return flexcan_set_bittiming_ctrl(dev);
}

static void flexcan_ram_init(struct net_device *dev)
{
        struct flexcan_priv *priv = netdev_priv(dev);
        struct flexcan_regs __iomem *regs = priv->regs;
        u32 reg_ctrl2;

        /* 11.8.3.13 Detection and correction of memory errors:
         * CTRL2[WRMFRZ] grants write access to all memory positions
         * that require initialization, ranging from 0x080 to 0xADF
         * and from 0xF28 to 0xFFF when the CAN FD feature is enabled.
         * The RXMGMASK, RX14MASK, RX15MASK, and RXFGMASK registers
         * need to be initialized as well. MCR[RFEN] must not be set
         * during memory initialization.
         */
        reg_ctrl2 = priv->read(&regs->ctrl2);
        reg_ctrl2 |= FLEXCAN_CTRL2_WRMFRZ;
        priv->write(reg_ctrl2, &regs->ctrl2);

        memset_io(&regs->init, 0, sizeof(regs->init));

        if (priv->can.ctrlmode & CAN_CTRLMODE_FD)
                memset_io(&regs->init_fd, 0, sizeof(regs->init_fd));

        reg_ctrl2 &= ~FLEXCAN_CTRL2_WRMFRZ;
        priv->write(reg_ctrl2, &regs->ctrl2);
}

static int flexcan_rx_offload_setup(struct net_device *dev)
{
        struct flexcan_priv *priv = netdev_priv(dev);
        int err;

        if (priv->can.ctrlmode & CAN_CTRLMODE_FD)
                priv->mb_size = sizeof(struct flexcan_mb) + CANFD_MAX_DLEN;
        else
                priv->mb_size = sizeof(struct flexcan_mb) + CAN_MAX_DLEN;

        if (priv->devtype_data.quirks & FLEXCAN_QUIRK_NR_MB_16)
                priv->mb_count = 16;
        else
                priv->mb_count = (sizeof(priv->regs->mb[0]) / priv->mb_size) +
                                 (sizeof(priv->regs->mb[1]) / priv->mb_size);

        if (priv->devtype_data.quirks & FLEXCAN_QUIRK_USE_RX_MAILBOX)
                priv->tx_mb_reserved =
                        flexcan_get_mb(priv, FLEXCAN_TX_MB_RESERVED_RX_MAILBOX);
        else
                priv->tx_mb_reserved =
                        flexcan_get_mb(priv, FLEXCAN_TX_MB_RESERVED_RX_FIFO);
        priv->tx_mb_idx = priv->mb_count - 1;
        priv->tx_mb = flexcan_get_mb(priv, priv->tx_mb_idx);
        priv->tx_mask = FLEXCAN_IFLAG_MB(priv->tx_mb_idx);

        priv->offload.mailbox_read = flexcan_mailbox_read;

        if (priv->devtype_data.quirks & FLEXCAN_QUIRK_USE_RX_MAILBOX) {
                priv->offload.mb_first = FLEXCAN_RX_MB_RX_MAILBOX_FIRST;
                priv->offload.mb_last = priv->mb_count - 2;

                priv->rx_mask = GENMASK_ULL(priv->offload.mb_last,
                                            priv->offload.mb_first);
                err = can_rx_offload_add_timestamp(dev, &priv->offload);
        } else {
                priv->rx_mask = FLEXCAN_IFLAG_RX_FIFO_OVERFLOW |
                        FLEXCAN_IFLAG_RX_FIFO_AVAILABLE;
                err = can_rx_offload_add_fifo(dev, &priv->offload,
                                              FLEXCAN_NAPI_WEIGHT);
        }

        return err;
}

static void flexcan_chip_interrupts_enable(const struct net_device *dev)
{
        const struct flexcan_priv *priv = netdev_priv(dev);
        struct flexcan_regs __iomem *regs = priv->regs;
        u64 reg_imask;

        disable_irq(dev->irq);
        priv->write(priv->reg_ctrl_default, &regs->ctrl);
        reg_imask = priv->rx_mask | priv->tx_mask;
        priv->write(upper_32_bits(reg_imask), &regs->imask2);
        priv->write(lower_32_bits(reg_imask), &regs->imask1);
        enable_irq(dev->irq);
}

static void flexcan_chip_interrupts_disable(const struct net_device *dev)
{
        const struct flexcan_priv *priv = netdev_priv(dev);
        struct flexcan_regs __iomem *regs = priv->regs;

        priv->write(0, &regs->imask2);
        priv->write(0, &regs->imask1);
        priv->write(priv->reg_ctrl_default & ~FLEXCAN_CTRL_ERR_ALL,
                    &regs->ctrl);
}

/* flexcan_chip_start
 *
 * this functions is entered with clocks enabled
 *
 */
static int flexcan_chip_start(struct net_device *dev)
{
        struct flexcan_priv *priv = netdev_priv(dev);
        struct flexcan_regs __iomem *regs = priv->regs;
        u32 reg_mcr, reg_ctrl, reg_ctrl2, reg_mecr;
        int err, i;
        struct flexcan_mb __iomem *mb;

        /* enable module */
        err = flexcan_chip_enable(priv);
        if (err)
                return err;

        /* soft reset */
        err = flexcan_chip_softreset(priv);
        if (err)
                goto out_chip_disable;

        if (priv->devtype_data.quirks & FLEXCAN_QUIRK_SUPPORT_ECC)
                flexcan_ram_init(dev);

        flexcan_set_bittiming(dev);

        /* set freeze, halt */
        err = flexcan_chip_freeze(priv);
        if (err)
                goto out_chip_disable;

        /* MCR
         *
         * only supervisor access
         * enable warning int
         * enable individual RX masking
         * choose format C
         * set max mailbox number
         */
        reg_mcr = priv->read(&regs->mcr);
        reg_mcr &= ~FLEXCAN_MCR_MAXMB(0xff);
        reg_mcr |= FLEXCAN_MCR_SUPV | FLEXCAN_MCR_WRN_EN | FLEXCAN_MCR_IRMQ |
                FLEXCAN_MCR_IDAM_C | FLEXCAN_MCR_MAXMB(priv->tx_mb_idx);

        /* MCR
         *
         * FIFO:
         * - disable for mailbox mode
         * - enable for FIFO mode
         */
        if (priv->devtype_data.quirks & FLEXCAN_QUIRK_USE_RX_MAILBOX)
                reg_mcr &= ~FLEXCAN_MCR_FEN;
        else
                reg_mcr |= FLEXCAN_MCR_FEN;

        /* MCR
         *
         * NOTE: In loopback mode, the CAN_MCR[SRXDIS] cannot be
         *       asserted because this will impede the self reception
         *       of a transmitted message. This is not documented in
         *       earlier versions of flexcan block guide.
         *
         * Self Reception:
         * - enable Self Reception for loopback mode
         *   (by clearing "Self Reception Disable" bit)
         * - disable for normal operation
         */
        if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK)
                reg_mcr &= ~FLEXCAN_MCR_SRX_DIS;
        else
                reg_mcr |= FLEXCAN_MCR_SRX_DIS;

        /* MCR - CAN-FD */
        if (priv->can.ctrlmode & CAN_CTRLMODE_FD)
                reg_mcr |= FLEXCAN_MCR_FDEN;
        else
                reg_mcr &= ~FLEXCAN_MCR_FDEN;

        netdev_dbg(dev, "%s: writing mcr=0x%08x", __func__, reg_mcr);
        priv->write(reg_mcr, &regs->mcr);

        /* CTRL
         *
         * disable timer sync feature
         *
         * disable auto busoff recovery
         * transmit lowest buffer first
         *
         * enable tx and rx warning interrupt
         * enable bus off interrupt
         * (== FLEXCAN_CTRL_ERR_STATE)
         */
        reg_ctrl = priv->read(&regs->ctrl);
        reg_ctrl &= ~FLEXCAN_CTRL_TSYN;
        reg_ctrl |= FLEXCAN_CTRL_BOFF_REC | FLEXCAN_CTRL_LBUF |
                FLEXCAN_CTRL_ERR_STATE;

        /* enable the "error interrupt" (FLEXCAN_CTRL_ERR_MSK),
         * on most Flexcan cores, too. Otherwise we don't get
         * any error warning or passive interrupts.
         */
        if (priv->devtype_data.quirks & FLEXCAN_QUIRK_BROKEN_WERR_STATE ||
            priv->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING)
                reg_ctrl |= FLEXCAN_CTRL_ERR_MSK;
        else
                reg_ctrl &= ~FLEXCAN_CTRL_ERR_MSK;

        /* save for later use */
        priv->reg_ctrl_default = reg_ctrl;
        /* leave interrupts disabled for now */
        reg_ctrl &= ~FLEXCAN_CTRL_ERR_ALL;
        netdev_dbg(dev, "%s: writing ctrl=0x%08x", __func__, reg_ctrl);
        priv->write(reg_ctrl, &regs->ctrl);

        if ((priv->devtype_data.quirks & FLEXCAN_QUIRK_ENABLE_EACEN_RRS)) {
                reg_ctrl2 = priv->read(&regs->ctrl2);
                reg_ctrl2 |= FLEXCAN_CTRL2_EACEN | FLEXCAN_CTRL2_RRS;
                priv->write(reg_ctrl2, &regs->ctrl2);
        }

        if (priv->can.ctrlmode_supported & CAN_CTRLMODE_FD) {
                u32 reg_fdctrl;

                reg_fdctrl = priv->read(&regs->fdctrl);
                reg_fdctrl &= ~(FIELD_PREP(FLEXCAN_FDCTRL_MBDSR1, 0x3) |
                                FIELD_PREP(FLEXCAN_FDCTRL_MBDSR0, 0x3));

                if (priv->can.ctrlmode & CAN_CTRLMODE_FD) {
                        reg_fdctrl |=
                                FIELD_PREP(FLEXCAN_FDCTRL_MBDSR1,
                                           FLEXCAN_FDCTRL_MBDSR_64) |
                                FIELD_PREP(FLEXCAN_FDCTRL_MBDSR0,
                                           FLEXCAN_FDCTRL_MBDSR_64);
                } else {
                        reg_fdctrl |=
                                FIELD_PREP(FLEXCAN_FDCTRL_MBDSR1,
                                           FLEXCAN_FDCTRL_MBDSR_8) |
                                FIELD_PREP(FLEXCAN_FDCTRL_MBDSR0,
                                           FLEXCAN_FDCTRL_MBDSR_8);
                }

                netdev_dbg(dev, "%s: writing fdctrl=0x%08x",
                           __func__, reg_fdctrl);
                priv->write(reg_fdctrl, &regs->fdctrl);
        }

        if (priv->devtype_data.quirks & FLEXCAN_QUIRK_USE_RX_MAILBOX) {
                for (i = priv->offload.mb_first; i <= priv->offload.mb_last; i++) {
                        mb = flexcan_get_mb(priv, i);
                        priv->write(FLEXCAN_MB_CODE_RX_EMPTY,
                                    &mb->can_ctrl);
                }
        } else {
                /* clear and invalidate unused mailboxes first */
                for (i = FLEXCAN_TX_MB_RESERVED_RX_FIFO; i < priv->mb_count; i++) {
                        mb = flexcan_get_mb(priv, i);
                        priv->write(FLEXCAN_MB_CODE_RX_INACTIVE,
                                    &mb->can_ctrl);
                }
        }

        /* Errata ERR005829: mark first TX mailbox as INACTIVE */
        priv->write(FLEXCAN_MB_CODE_TX_INACTIVE,
                    &priv->tx_mb_reserved->can_ctrl);

        /* mark TX mailbox as INACTIVE */
        priv->write(FLEXCAN_MB_CODE_TX_INACTIVE,
                    &priv->tx_mb->can_ctrl);

        /* acceptance mask/acceptance code (accept everything) */
        priv->write(0x0, &regs->rxgmask);
        priv->write(0x0, &regs->rx14mask);
        priv->write(0x0, &regs->rx15mask);

        if (priv->devtype_data.quirks & FLEXCAN_QUIRK_DISABLE_RXFG)
                priv->write(0x0, &regs->rxfgmask);

        /* clear acceptance filters */
        for (i = 0; i < priv->mb_count; i++)
                priv->write(0, &regs->rximr[i]);

        /* On Vybrid, disable non-correctable errors interrupt and
         * freeze mode. It still can correct the correctable errors
         * when HW supports ECC.
         *
         * This also works around errata e5295 which generates false
         * positive memory errors and put the device in freeze mode.
         */
        if (priv->devtype_data.quirks & FLEXCAN_QUIRK_DISABLE_MECR) {
                /* Follow the protocol as described in "Detection
                 * and Correction of Memory Errors" to write to
                 * MECR register (step 1 - 5)
                 *
                 * 1. By default, CTRL2[ECRWRE] = 0, MECR[ECRWRDIS] = 1
                 * 2. set CTRL2[ECRWRE]
                 */
                reg_ctrl2 = priv->read(&regs->ctrl2);
                reg_ctrl2 |= FLEXCAN_CTRL2_ECRWRE;
                priv->write(reg_ctrl2, &regs->ctrl2);

                /* 3. clear MECR[ECRWRDIS] */
                reg_mecr = priv->read(&regs->mecr);
                reg_mecr &= ~FLEXCAN_MECR_ECRWRDIS;
                priv->write(reg_mecr, &regs->mecr);

                /* 4. all writes to MECR must keep MECR[ECRWRDIS] cleared */
                reg_mecr &= ~(FLEXCAN_MECR_NCEFAFRZ | FLEXCAN_MECR_HANCEI_MSK |
                              FLEXCAN_MECR_FANCEI_MSK);
                priv->write(reg_mecr, &regs->mecr);

                /* 5. after configuration done, lock MECR by either
                 * setting MECR[ECRWRDIS] or clearing CTRL2[ECRWRE]
                 */
                reg_mecr |= FLEXCAN_MECR_ECRWRDIS;
                priv->write(reg_mecr, &regs->mecr);

                reg_ctrl2 &= ~FLEXCAN_CTRL2_ECRWRE;
                priv->write(reg_ctrl2, &regs->ctrl2);
        }

        /* synchronize with the can bus */
        err = flexcan_chip_unfreeze(priv);
        if (err)
                goto out_chip_disable;

        priv->can.state = CAN_STATE_ERROR_ACTIVE;

        /* print chip status */
        netdev_dbg(dev, "%s: reading mcr=0x%08x ctrl=0x%08x\n", __func__,
                   priv->read(&regs->mcr), priv->read(&regs->ctrl));

        return 0;

 out_chip_disable:
        flexcan_chip_disable(priv);
        return err;
}

/* __flexcan_chip_stop
 *
 * this function is entered with clocks enabled
 */
static int __flexcan_chip_stop(struct net_device *dev, bool disable_on_error)
{
        struct flexcan_priv *priv = netdev_priv(dev);
        int err;

        /* freeze + disable module */
        err = flexcan_chip_freeze(priv);
        if (err && !disable_on_error)
                return err;
        err = flexcan_chip_disable(priv);
        if (err && !disable_on_error)
                goto out_chip_unfreeze;

        priv->can.state = CAN_STATE_STOPPED;

        return 0;

 out_chip_unfreeze:
        flexcan_chip_unfreeze(priv);

        return err;
}

static inline int flexcan_chip_stop_disable_on_error(struct net_device *dev)
{
        return __flexcan_chip_stop(dev, true);
}

static inline int flexcan_chip_stop(struct net_device *dev)
{
        return __flexcan_chip_stop(dev, false);
}

static int flexcan_open(struct net_device *dev)
{
        struct flexcan_priv *priv = netdev_priv(dev);
        int err;

        if ((priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES) &&
            (priv->can.ctrlmode & CAN_CTRLMODE_FD)) {
                netdev_err(dev, "Three Samples mode and CAN-FD mode can't be used together\n");
                return -EINVAL;
        }

        err = pm_runtime_get_sync(priv->dev);
        if (err < 0) {
                pm_runtime_put_noidle(priv->dev);
                return err;
        }

        err = open_candev(dev);
        if (err)
                goto out_runtime_put;

        err = flexcan_transceiver_enable(priv);
        if (err)
                goto out_close;

        err = flexcan_rx_offload_setup(dev);
        if (err)
                goto out_transceiver_disable;

        err = flexcan_chip_start(dev);
        if (err)
                goto out_can_rx_offload_del;

        can_rx_offload_enable(&priv->offload);

        err = request_irq(dev->irq, flexcan_irq, IRQF_SHARED, dev->name, dev);
        if (err)
                goto out_can_rx_offload_disable;

        if (priv->devtype_data.quirks & FLEXCAN_QUIRK_NR_IRQ_3) {
                err = request_irq(priv->irq_boff,
                                  flexcan_irq, IRQF_SHARED, dev->name, dev);
                if (err)
                        goto out_free_irq;

                err = request_irq(priv->irq_err,
                                  flexcan_irq, IRQF_SHARED, dev->name, dev);
                if (err)
                        goto out_free_irq_boff;
        }

        flexcan_chip_interrupts_enable(dev);

        can_led_event(dev, CAN_LED_EVENT_OPEN);

        netif_start_queue(dev);

        return 0;

 out_free_irq_boff:
        free_irq(priv->irq_boff, dev);
 out_free_irq:
        free_irq(dev->irq, dev);
 out_can_rx_offload_disable:
        can_rx_offload_disable(&priv->offload);
        flexcan_chip_stop(dev);
 out_can_rx_offload_del:
        can_rx_offload_del(&priv->offload);
 out_transceiver_disable:
        flexcan_transceiver_disable(priv);
 out_close:
        close_candev(dev);
 out_runtime_put:
        pm_runtime_put(priv->dev);

        return err;
}

static int flexcan_close(struct net_device *dev)
{
        struct flexcan_priv *priv = netdev_priv(dev);

        netif_stop_queue(dev);
        flexcan_chip_interrupts_disable(dev);

        if (priv->devtype_data.quirks & FLEXCAN_QUIRK_NR_IRQ_3) {
                free_irq(priv->irq_err, dev);
                free_irq(priv->irq_boff, dev);
        }

        free_irq(dev->irq, dev);
        can_rx_offload_disable(&priv->offload);
        flexcan_chip_stop_disable_on_error(dev);

        can_rx_offload_del(&priv->offload);
        flexcan_transceiver_disable(priv);
        close_candev(dev);

        pm_runtime_put(priv->dev);

        can_led_event(dev, CAN_LED_EVENT_STOP);

        return 0;
}

static int flexcan_set_mode(struct net_device *dev, enum can_mode mode)
{
        int err;

        switch (mode) {
        case CAN_MODE_START:
                err = flexcan_chip_start(dev);
                if (err)
                        return err;

                flexcan_chip_interrupts_enable(dev);

                netif_wake_queue(dev);
                break;

        default:
                return -EOPNOTSUPP;
        }

        return 0;
}

static const struct net_device_ops flexcan_netdev_ops = {
        .ndo_open       = flexcan_open,
        .ndo_stop       = flexcan_close,
        .ndo_start_xmit = flexcan_start_xmit,
        .ndo_change_mtu = can_change_mtu,
};

static int register_flexcandev(struct net_device *dev)
{
        struct flexcan_priv *priv = netdev_priv(dev);
        struct flexcan_regs __iomem *regs = priv->regs;
        u32 reg, err;

        err = flexcan_clks_enable(priv);
        if (err)
                return err;

        /* select "bus clock", chip must be disabled */
        err = flexcan_chip_disable(priv);
        if (err)
                goto out_clks_disable;

        reg = priv->read(&regs->ctrl);
        if (priv->clk_src)
                reg |= FLEXCAN_CTRL_CLK_SRC;
        else
                reg &= ~FLEXCAN_CTRL_CLK_SRC;
        priv->write(reg, &regs->ctrl);

        err = flexcan_chip_enable(priv);
        if (err)
                goto out_chip_disable;

        /* set freeze, halt */
        err = flexcan_chip_freeze(priv);
        if (err)
                goto out_chip_disable;

        /* activate FIFO, restrict register access */
        reg = priv->read(&regs->mcr);
        reg |=  FLEXCAN_MCR_FEN | FLEXCAN_MCR_SUPV;
        priv->write(reg, &regs->mcr);

        /* Currently we only support newer versions of this core
         * featuring a RX hardware FIFO (although this driver doesn't
         * make use of it on some cores). Older cores, found on some
         * Coldfire derivates are not tested.
         */
        reg = priv->read(&regs->mcr);
        if (!(reg & FLEXCAN_MCR_FEN)) {
                netdev_err(dev, "Could not enable RX FIFO, unsupported core\n");
                err = -ENODEV;
                goto out_chip_disable;
        }

        err = register_candev(dev);
        if (err)
                goto out_chip_disable;

        /* Disable core and let pm_runtime_put() disable the clocks.
         * If CONFIG_PM is not enabled, the clocks will stay powered.
         */
        flexcan_chip_disable(priv);
        pm_runtime_put(priv->dev);

        return 0;

 out_chip_disable:
        flexcan_chip_disable(priv);
 out_clks_disable:
        flexcan_clks_disable(priv);
        return err;
}

static void unregister_flexcandev(struct net_device *dev)
{
        unregister_candev(dev);
}

static int flexcan_setup_stop_mode_gpr(struct platform_device *pdev)
{
        struct net_device *dev = platform_get_drvdata(pdev);
        struct device_node *np = pdev->dev.of_node;
        struct device_node *gpr_np;
        struct flexcan_priv *priv;
        phandle phandle;
        u32 out_val[3];
        int ret;

        if (!np)
                return -EINVAL;

        /* stop mode property format is:
         * <&gpr req_gpr req_bit>.
         */
        ret = of_property_read_u32_array(np, "fsl,stop-mode", out_val,
                                         ARRAY_SIZE(out_val));
        if (ret) {
                dev_dbg(&pdev->dev, "no stop-mode property\n");
                return ret;
        }
        phandle = *out_val;

        gpr_np = of_find_node_by_phandle(phandle);
        if (!gpr_np) {
                dev_dbg(&pdev->dev, "could not find gpr node by phandle\n");
                return -ENODEV;
        }

        priv = netdev_priv(dev);
        priv->stm.gpr = syscon_node_to_regmap(gpr_np);
        if (IS_ERR(priv->stm.gpr)) {
                dev_dbg(&pdev->dev, "could not find gpr regmap\n");
                ret = PTR_ERR(priv->stm.gpr);
                goto out_put_node;
        }

        priv->stm.req_gpr = out_val[1];
        priv->stm.req_bit = out_val[2];

        dev_dbg(&pdev->dev,
                "gpr %s req_gpr=0x02%x req_bit=%u\n",
                gpr_np->full_name, priv->stm.req_gpr, priv->stm.req_bit);

        return 0;

out_put_node:
        of_node_put(gpr_np);
        return ret;
}

static int flexcan_setup_stop_mode_scfw(struct platform_device *pdev)
{
        struct net_device *dev = platform_get_drvdata(pdev);
        struct flexcan_priv *priv;
        u8 scu_idx;
        int ret;

        ret = of_property_read_u8(pdev->dev.of_node, "fsl,scu-index", &scu_idx);
        if (ret < 0) {
                dev_dbg(&pdev->dev, "failed to get scu index\n");
                return ret;
        }

        priv = netdev_priv(dev);
        priv->scu_idx = scu_idx;

        /* this function could be deferred probe, return -EPROBE_DEFER */
        return imx_scu_get_handle(&priv->sc_ipc_handle);
}

/* flexcan_setup_stop_mode - Setup stop mode for wakeup
 *
 * Return: = 0 setup stop mode successfully or doesn't support this feature
 *         < 0 fail to setup stop mode (could be deferred probe)
 */
static int flexcan_setup_stop_mode(struct platform_device *pdev)
{
        struct net_device *dev = platform_get_drvdata(pdev);
        struct flexcan_priv *priv;
        int ret;

        priv = netdev_priv(dev);

        if (priv->devtype_data.quirks & FLEXCAN_QUIRK_SETUP_STOP_MODE_SCFW)
                ret = flexcan_setup_stop_mode_scfw(pdev);
        else if (priv->devtype_data.quirks & FLEXCAN_QUIRK_SETUP_STOP_MODE_GPR)
                ret = flexcan_setup_stop_mode_gpr(pdev);
        else
                /* return 0 directly if doesn't support stop mode feature */
                return 0;

        if (ret)
                return ret;

        device_set_wakeup_capable(&pdev->dev, true);

        if (of_property_read_bool(pdev->dev.of_node, "wakeup-source"))
                device_set_wakeup_enable(&pdev->dev, true);

        return 0;
}

static const struct of_device_id flexcan_of_match[] = {
        { .compatible = "fsl,imx8qm-flexcan", .data = &fsl_imx8qm_devtype_data, },
        { .compatible = "fsl,imx8mp-flexcan", .data = &fsl_imx8mp_devtype_data, },
        { .compatible = "fsl,imx6q-flexcan", .data = &fsl_imx6q_devtype_data, },
        { .compatible = "fsl,imx28-flexcan", .data = &fsl_imx28_devtype_data, },
        { .compatible = "fsl,imx53-flexcan", .data = &fsl_imx25_devtype_data, },
        { .compatible = "fsl,imx35-flexcan", .data = &fsl_imx25_devtype_data, },
        { .compatible = "fsl,imx25-flexcan", .data = &fsl_imx25_devtype_data, },
        { .compatible = "fsl,p1010-flexcan", .data = &fsl_p1010_devtype_data, },
        { .compatible = "fsl,vf610-flexcan", .data = &fsl_vf610_devtype_data, },
        { .compatible = "fsl,ls1021ar2-flexcan", .data = &fsl_ls1021a_r2_devtype_data, },
        { .compatible = "fsl,lx2160ar1-flexcan", .data = &fsl_lx2160a_r1_devtype_data, },
        { /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, flexcan_of_match);

static const struct platform_device_id flexcan_id_table[] = {
        {
                .name = "flexcan-mcf5441x",
                .driver_data = (kernel_ulong_t)&fsl_mcf5441x_devtype_data,
        }, {
                /* sentinel */
        },
};
MODULE_DEVICE_TABLE(platform, flexcan_id_table);

static int flexcan_probe(struct platform_device *pdev)
{
        const struct of_device_id *of_id;
        const struct flexcan_devtype_data *devtype_data;
        struct net_device *dev;
        struct flexcan_priv *priv;
        struct regulator *reg_xceiver;
        struct clk *clk_ipg = NULL, *clk_per = NULL;
        struct flexcan_regs __iomem *regs;
        struct flexcan_platform_data *pdata;
        int err, irq;
        u8 clk_src = 1;
        u32 clock_freq = 0;

        reg_xceiver = devm_regulator_get_optional(&pdev->dev, "xceiver");
        if (PTR_ERR(reg_xceiver) == -EPROBE_DEFER)
                return -EPROBE_DEFER;
        else if (PTR_ERR(reg_xceiver) == -ENODEV)
                reg_xceiver = NULL;
        else if (IS_ERR(reg_xceiver))
                return PTR_ERR(reg_xceiver);

        if (pdev->dev.of_node) {
                of_property_read_u32(pdev->dev.of_node,
                                     "clock-frequency", &clock_freq);
                of_property_read_u8(pdev->dev.of_node,
                                    "fsl,clk-source", &clk_src);
        } else {
                pdata = dev_get_platdata(&pdev->dev);
                if (pdata) {
                        clock_freq = pdata->clock_frequency;
                        clk_src = pdata->clk_src;
                }
        }

        if (!clock_freq) {
                clk_ipg = devm_clk_get(&pdev->dev, "ipg");
                if (IS_ERR(clk_ipg)) {
                        dev_err(&pdev->dev, "no ipg clock defined\n");
                        return PTR_ERR(clk_ipg);
                }

                clk_per = devm_clk_get(&pdev->dev, "per");
                if (IS_ERR(clk_per)) {
                        dev_err(&pdev->dev, "no per clock defined\n");
                        return PTR_ERR(clk_per);
                }
                clock_freq = clk_get_rate(clk_per);
        }

        irq = platform_get_irq(pdev, 0);
        if (irq <= 0)
                return -ENODEV;

        regs = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(regs))
                return PTR_ERR(regs);

        of_id = of_match_device(flexcan_of_match, &pdev->dev);
        if (of_id)
                devtype_data = of_id->data;
        else if (platform_get_device_id(pdev)->driver_data)
                devtype_data = (struct flexcan_devtype_data *)
                        platform_get_device_id(pdev)->driver_data;
        else
                return -ENODEV;

        if ((devtype_data->quirks & FLEXCAN_QUIRK_SUPPORT_FD) &&
            !((devtype_data->quirks &
               (FLEXCAN_QUIRK_USE_RX_MAILBOX |
                FLEXCAN_QUIRK_SUPPPORT_RX_MAILBOX |
                FLEXCAN_QUIRK_SUPPPORT_RX_MAILBOX_RTR |
                FLEXCAN_QUIRK_SUPPPORT_RX_FIFO)) ==
              (FLEXCAN_QUIRK_USE_RX_MAILBOX |
               FLEXCAN_QUIRK_SUPPPORT_RX_MAILBOX |
               FLEXCAN_QUIRK_SUPPPORT_RX_MAILBOX_RTR))) {
                dev_err(&pdev->dev, "CAN-FD mode doesn't work in RX-FIFO mode!\n");
                return -EINVAL;
        }

        if ((devtype_data->quirks &
             (FLEXCAN_QUIRK_SUPPPORT_RX_MAILBOX |
              FLEXCAN_QUIRK_SUPPPORT_RX_MAILBOX_RTR)) ==
            FLEXCAN_QUIRK_SUPPPORT_RX_MAILBOX_RTR) {
                dev_err(&pdev->dev,
                        "Quirks (0x%08x) inconsistent: RX_MAILBOX_RX supported but not RX_MAILBOX\n",
                        devtype_data->quirks);
                return -EINVAL;
        }

        dev = alloc_candev(sizeof(struct flexcan_priv), 1);
        if (!dev)
                return -ENOMEM;

        platform_set_drvdata(pdev, dev);
        SET_NETDEV_DEV(dev, &pdev->dev);

        dev->netdev_ops = &flexcan_netdev_ops;
        flexcan_set_ethtool_ops(dev);
        dev->irq = irq;
        dev->flags |= IFF_ECHO;

        priv = netdev_priv(dev);
        priv->devtype_data = *devtype_data;

        if (of_property_read_bool(pdev->dev.of_node, "big-endian") ||
            priv->devtype_data.quirks & FLEXCAN_QUIRK_DEFAULT_BIG_ENDIAN) {
                priv->read = flexcan_read_be;
                priv->write = flexcan_write_be;
        } else {
                priv->read = flexcan_read_le;
                priv->write = flexcan_write_le;
        }

        priv->dev = &pdev->dev;
        priv->can.clock.freq = clock_freq;
        priv->can.do_set_mode = flexcan_set_mode;
        priv->can.do_get_berr_counter = flexcan_get_berr_counter;
        priv->can.ctrlmode_supported = CAN_CTRLMODE_LOOPBACK |
                CAN_CTRLMODE_LISTENONLY | CAN_CTRLMODE_3_SAMPLES |
                CAN_CTRLMODE_BERR_REPORTING;
        priv->regs = regs;
        priv->clk_ipg = clk_ipg;
        priv->clk_per = clk_per;
        priv->clk_src = clk_src;
        priv->reg_xceiver = reg_xceiver;

        if (priv->devtype_data.quirks & FLEXCAN_QUIRK_NR_IRQ_3) {
                priv->irq_boff = platform_get_irq(pdev, 1);
                if (priv->irq_boff <= 0) {
                        err = -ENODEV;
                        goto failed_platform_get_irq;
                }
                priv->irq_err = platform_get_irq(pdev, 2);
                if (priv->irq_err <= 0) {
                        err = -ENODEV;
                        goto failed_platform_get_irq;
                }
        }

        if (priv->devtype_data.quirks & FLEXCAN_QUIRK_SUPPORT_FD) {
                priv->can.ctrlmode_supported |= CAN_CTRLMODE_FD |
                        CAN_CTRLMODE_FD_NON_ISO;
                priv->can.bittiming_const = &flexcan_fd_bittiming_const;
                priv->can.data_bittiming_const =
                        &flexcan_fd_data_bittiming_const;
        } else {
                priv->can.bittiming_const = &flexcan_bittiming_const;
        }

        pm_runtime_get_noresume(&pdev->dev);
        pm_runtime_set_active(&pdev->dev);
        pm_runtime_enable(&pdev->dev);

        err = register_flexcandev(dev);
        if (err) {
                dev_err(&pdev->dev, "registering netdev failed\n");
                goto failed_register;
        }

        err = flexcan_setup_stop_mode(pdev);
        if (err < 0) {
                if (err != -EPROBE_DEFER)
                        dev_err(&pdev->dev, "setup stop mode failed\n");
                goto failed_setup_stop_mode;
        }

        of_can_transceiver(dev);
        devm_can_led_init(dev);

        return 0;

 failed_setup_stop_mode:
        unregister_flexcandev(dev);
 failed_register:
        pm_runtime_put_noidle(&pdev->dev);
        pm_runtime_disable(&pdev->dev);
 failed_platform_get_irq:
        free_candev(dev);
        return err;
}

static int flexcan_remove(struct platform_device *pdev)
{
        struct net_device *dev = platform_get_drvdata(pdev);

        device_set_wakeup_enable(&pdev->dev, false);
        device_set_wakeup_capable(&pdev->dev, false);
        unregister_flexcandev(dev);
        pm_runtime_disable(&pdev->dev);
        free_candev(dev);

        return 0;
}

static int __maybe_unused flexcan_suspend(struct device *device)
{
        struct net_device *dev = dev_get_drvdata(device);
        struct flexcan_priv *priv = netdev_priv(dev);
        int err;

        if (netif_running(dev)) {
                /* if wakeup is enabled, enter stop mode
                 * else enter disabled mode.
                 */
                if (device_may_wakeup(device)) {
                        enable_irq_wake(dev->irq);
                        err = flexcan_enter_stop_mode(priv);
                        if (err)
                                return err;
                } else {
                        err = flexcan_chip_stop(dev);
                        if (err)
                                return err;

                        flexcan_chip_interrupts_disable(dev);

                        err = pinctrl_pm_select_sleep_state(device);
                        if (err)
                                return err;
                }
                netif_stop_queue(dev);
                netif_device_detach(dev);
        }
        priv->can.state = CAN_STATE_SLEEPING;

        return 0;
}

static int __maybe_unused flexcan_resume(struct device *device)
{
        struct net_device *dev = dev_get_drvdata(device);
        struct flexcan_priv *priv = netdev_priv(dev);
        int err;

        priv->can.state = CAN_STATE_ERROR_ACTIVE;
        if (netif_running(dev)) {
                netif_device_attach(dev);
                netif_start_queue(dev);
                if (device_may_wakeup(device)) {
                        disable_irq_wake(dev->irq);
                        err = flexcan_exit_stop_mode(priv);
                        if (err)
                                return err;
                } else {
                        err = pinctrl_pm_select_default_state(device);
                        if (err)
                                return err;

                        err = flexcan_chip_start(dev);
                        if (err)
                                return err;

                        flexcan_chip_interrupts_enable(dev);
                }
        }

        return 0;
}

static int __maybe_unused flexcan_runtime_suspend(struct device *device)
{
        struct net_device *dev = dev_get_drvdata(device);
        struct flexcan_priv *priv = netdev_priv(dev);

        flexcan_clks_disable(priv);

        return 0;
}

static int __maybe_unused flexcan_runtime_resume(struct device *device)
{
        struct net_device *dev = dev_get_drvdata(device);
        struct flexcan_priv *priv = netdev_priv(dev);

        return flexcan_clks_enable(priv);
}

static int __maybe_unused flexcan_noirq_suspend(struct device *device)
{
        struct net_device *dev = dev_get_drvdata(device);
        struct flexcan_priv *priv = netdev_priv(dev);

        if (netif_running(dev)) {
                int err;

                if (device_may_wakeup(device))
                        flexcan_enable_wakeup_irq(priv, true);

                err = pm_runtime_force_suspend(device);
                if (err)
                        return err;
        }

        return 0;
}

static int __maybe_unused flexcan_noirq_resume(struct device *device)
{
        struct net_device *dev = dev_get_drvdata(device);
        struct flexcan_priv *priv = netdev_priv(dev);

        if (netif_running(dev)) {
                int err;

                err = pm_runtime_force_resume(device);
                if (err)
                        return err;

                if (device_may_wakeup(device))
                        flexcan_enable_wakeup_irq(priv, false);
        }

        return 0;
}

static const struct dev_pm_ops flexcan_pm_ops = {
        SET_SYSTEM_SLEEP_PM_OPS(flexcan_suspend, flexcan_resume)
        SET_RUNTIME_PM_OPS(flexcan_runtime_suspend, flexcan_runtime_resume, NULL)
        SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(flexcan_noirq_suspend, flexcan_noirq_resume)
};

static struct platform_driver flexcan_driver = {
        .driver = {
                .name = DRV_NAME,
                .pm = &flexcan_pm_ops,
                .of_match_table = flexcan_of_match,
        },
        .probe = flexcan_probe,
        .remove = flexcan_remove,
        .id_table = flexcan_id_table,
};

module_platform_driver(flexcan_driver);

MODULE_AUTHOR("Sascha Hauer <kernel@pengutronix.de>, "
              "Marc Kleine-Budde <kernel@pengutronix.de>");
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("CAN port driver for flexcan based chip");