root/drivers/net/can/usb/nct6694_canfd.c
// SPDX-License-Identifier: GPL-2.0
/* Nuvoton NCT6694 Socket CANfd driver based on USB interface.
 *
 * Copyright (C) 2025 Nuvoton Technology Corp.
 */

#include <linux/bitfield.h>
#include <linux/can/dev.h>
#include <linux/can/rx-offload.h>
#include <linux/ethtool.h>
#include <linux/idr.h>
#include <linux/irqdomain.h>
#include <linux/kernel.h>
#include <linux/mfd/nct6694.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/platform_device.h>

#define DEVICE_NAME "nct6694-canfd"

/* USB command module type for NCT6694 CANfd controller.
 * This defines the module type used for communication with the NCT6694
 * CANfd controller over the USB interface.
 */
#define NCT6694_CANFD_MOD                       0x05

/* Command 00h - CAN Setting and Initialization */
#define NCT6694_CANFD_SETTING                   0x00
#define NCT6694_CANFD_SETTING_ACTIVE_CTRL1      BIT(0)
#define NCT6694_CANFD_SETTING_ACTIVE_CTRL2      BIT(1)
#define NCT6694_CANFD_SETTING_ACTIVE_NBTP_DBTP  BIT(2)
#define NCT6694_CANFD_SETTING_CTRL1_MON         BIT(0)
#define NCT6694_CANFD_SETTING_CTRL1_NISO        BIT(1)
#define NCT6694_CANFD_SETTING_CTRL1_LBCK        BIT(2)
#define NCT6694_CANFD_SETTING_NBTP_NTSEG2       GENMASK(6, 0)
#define NCT6694_CANFD_SETTING_NBTP_NTSEG1       GENMASK(15, 8)
#define NCT6694_CANFD_SETTING_NBTP_NBRP         GENMASK(24, 16)
#define NCT6694_CANFD_SETTING_NBTP_NSJW         GENMASK(31, 25)
#define NCT6694_CANFD_SETTING_DBTP_DSJW         GENMASK(3, 0)
#define NCT6694_CANFD_SETTING_DBTP_DTSEG2       GENMASK(7, 4)
#define NCT6694_CANFD_SETTING_DBTP_DTSEG1       GENMASK(12, 8)
#define NCT6694_CANFD_SETTING_DBTP_DBRP         GENMASK(20, 16)
#define NCT6694_CANFD_SETTING_DBTP_TDC          BIT(23)

/* Command 01h - CAN Information */
#define NCT6694_CANFD_INFORMATION               0x01
#define NCT6694_CANFD_INFORMATION_SEL           0x00

/* Command 02h - CAN Event */
#define NCT6694_CANFD_EVENT                     0x02
#define NCT6694_CANFD_EVENT_SEL(idx, mask)      \
        ((idx ? 0x80 : 0x00) | ((mask) & 0x7F))

#define NCT6694_CANFD_EVENT_MASK                GENMASK(5, 0)
#define NCT6694_CANFD_EVT_TX_FIFO_EMPTY         BIT(7)  /* Read-clear */
#define NCT6694_CANFD_EVT_RX_DATA_LOST          BIT(5)  /* Read-clear */
#define NCT6694_CANFD_EVT_RX_DATA_IN            BIT(7)  /* Read-clear */

/* Command 10h - CAN Deliver */
#define NCT6694_CANFD_DELIVER                   0x10
#define NCT6694_CANFD_DELIVER_SEL(buf_cnt)      \
        ((buf_cnt) & 0xFF)

/* Command 11h - CAN Receive */
#define NCT6694_CANFD_RECEIVE                   0x11
#define NCT6694_CANFD_RECEIVE_SEL(idx, buf_cnt) \
        ((idx ? 0x80 : 0x00) | ((buf_cnt) & 0x7F))

#define NCT6694_CANFD_FRAME_TAG(idx)            (0xC0 | (idx))
#define NCT6694_CANFD_FRAME_FLAG_EFF            BIT(0)
#define NCT6694_CANFD_FRAME_FLAG_RTR            BIT(1)
#define NCT6694_CANFD_FRAME_FLAG_FD             BIT(2)
#define NCT6694_CANFD_FRAME_FLAG_BRS            BIT(3)
#define NCT6694_CANFD_FRAME_FLAG_ERR            BIT(4)

#define NCT6694_NAPI_WEIGHT                     32

enum nct6694_event_err {
        NCT6694_CANFD_EVT_ERR_NO_ERROR = 0,
        NCT6694_CANFD_EVT_ERR_CRC_ERROR,
        NCT6694_CANFD_EVT_ERR_STUFF_ERROR,
        NCT6694_CANFD_EVT_ERR_ACK_ERROR,
        NCT6694_CANFD_EVT_ERR_FORM_ERROR,
        NCT6694_CANFD_EVT_ERR_BIT_ERROR,
        NCT6694_CANFD_EVT_ERR_TIMEOUT_ERROR,
        NCT6694_CANFD_EVT_ERR_UNKNOWN_ERROR,
};

enum nct6694_event_status {
        NCT6694_CANFD_EVT_STS_ERROR_ACTIVE = 0,
        NCT6694_CANFD_EVT_STS_ERROR_PASSIVE,
        NCT6694_CANFD_EVT_STS_BUS_OFF,
        NCT6694_CANFD_EVT_STS_WARNING,
};

struct __packed nct6694_canfd_setting {
        __le32 nbr;
        __le32 dbr;
        u8 active;
        u8 reserved[3];
        __le16 ctrl1;
        __le16 ctrl2;
        __le32 nbtp;
        __le32 dbtp;
};

struct __packed nct6694_canfd_information {
        u8 tx_fifo_cnt;
        u8 rx_fifo_cnt;
        u8 reserved[2];
        __le32 can_clk;
};

struct __packed nct6694_canfd_event {
        u8 err;
        u8 status;
        u8 tx_evt;
        u8 rx_evt;
        u8 rec;
        u8 tec;
        u8 reserved[2];
};

struct __packed nct6694_canfd_frame {
        u8 tag;
        u8 flag;
        u8 reserved;
        u8 length;
        __le32 id;
        u8 data[CANFD_MAX_DLEN];
};

struct nct6694_canfd_priv {
        struct can_priv can;    /* must be the first member */
        struct can_rx_offload offload;
        struct net_device *ndev;
        struct nct6694 *nct6694;
        struct workqueue_struct *wq;
        struct work_struct tx_work;
        struct nct6694_canfd_frame tx;
        struct nct6694_canfd_frame rx;
        struct nct6694_canfd_event event[2];
        struct can_berr_counter bec;
};

static inline struct nct6694_canfd_priv *rx_offload_to_priv(struct can_rx_offload *offload)
{
        return container_of(offload, struct nct6694_canfd_priv, offload);
}

static const struct can_bittiming_const nct6694_canfd_bittiming_nominal_const = {
        .name = DEVICE_NAME,
        .tseg1_min = 1,
        .tseg1_max = 256,
        .tseg2_min = 1,
        .tseg2_max = 128,
        .sjw_max = 128,
        .brp_min = 1,
        .brp_max = 512,
        .brp_inc = 1,
};

static const struct can_bittiming_const nct6694_canfd_bittiming_data_const = {
        .name = DEVICE_NAME,
        .tseg1_min = 1,
        .tseg1_max = 32,
        .tseg2_min = 1,
        .tseg2_max = 16,
        .sjw_max = 16,
        .brp_min = 1,
        .brp_max = 32,
        .brp_inc = 1,
};

static void nct6694_canfd_rx_offload(struct can_rx_offload *offload,
                                     struct sk_buff *skb)
{
        struct nct6694_canfd_priv *priv = rx_offload_to_priv(offload);
        int ret;

        ret = can_rx_offload_queue_tail(offload, skb);
        if (ret)
                priv->ndev->stats.rx_fifo_errors++;
}

static void nct6694_canfd_handle_lost_msg(struct net_device *ndev)
{
        struct nct6694_canfd_priv *priv = netdev_priv(ndev);
        struct net_device_stats *stats = &ndev->stats;
        struct can_frame *cf;
        struct sk_buff *skb;

        netdev_dbg(ndev, "RX FIFO overflow, message(s) lost.\n");

        stats->rx_errors++;
        stats->rx_over_errors++;

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

        cf->can_id |= CAN_ERR_CRTL;
        cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;

        nct6694_canfd_rx_offload(&priv->offload, skb);
}

static void nct6694_canfd_handle_rx(struct net_device *ndev, u8 rx_evt)
{
        struct net_device_stats *stats = &ndev->stats;
        struct nct6694_canfd_priv *priv = netdev_priv(ndev);
        struct nct6694_canfd_frame *frame = &priv->rx;
        const struct nct6694_cmd_header cmd_hd = {
                .mod = NCT6694_CANFD_MOD,
                .cmd = NCT6694_CANFD_RECEIVE,
                .sel = NCT6694_CANFD_RECEIVE_SEL(ndev->dev_port, 1),
                .len = cpu_to_le16(sizeof(*frame))
        };
        struct sk_buff *skb;
        int ret;

        ret = nct6694_read_msg(priv->nct6694, &cmd_hd, frame);
        if (ret)
                return;

        if (frame->flag & NCT6694_CANFD_FRAME_FLAG_FD) {
                struct canfd_frame *cfd;

                skb = alloc_canfd_skb(priv->ndev, &cfd);
                if (!skb) {
                        stats->rx_dropped++;
                        return;
                }

                cfd->can_id = le32_to_cpu(frame->id);
                cfd->len = canfd_sanitize_len(frame->length);
                if (frame->flag & NCT6694_CANFD_FRAME_FLAG_EFF)
                        cfd->can_id |= CAN_EFF_FLAG;
                if (frame->flag & NCT6694_CANFD_FRAME_FLAG_BRS)
                        cfd->flags |= CANFD_BRS;
                if (frame->flag & NCT6694_CANFD_FRAME_FLAG_ERR)
                        cfd->flags |= CANFD_ESI;

                memcpy(cfd->data, frame->data, cfd->len);
        } else {
                struct can_frame *cf;

                skb = alloc_can_skb(priv->ndev, &cf);
                if (!skb) {
                        stats->rx_dropped++;
                        return;
                }

                cf->can_id = le32_to_cpu(frame->id);
                cf->len = can_cc_dlc2len(frame->length);
                if (frame->flag & NCT6694_CANFD_FRAME_FLAG_EFF)
                        cf->can_id |= CAN_EFF_FLAG;

                if (frame->flag & NCT6694_CANFD_FRAME_FLAG_RTR)
                        cf->can_id |= CAN_RTR_FLAG;
                else
                        memcpy(cf->data, frame->data, cf->len);
        }

        nct6694_canfd_rx_offload(&priv->offload, skb);
}

static int nct6694_canfd_get_berr_counter(const struct net_device *ndev,
                                          struct can_berr_counter *bec)
{
        struct nct6694_canfd_priv *priv = netdev_priv(ndev);

        *bec = priv->bec;

        return 0;
}

static void nct6694_canfd_handle_state_change(struct net_device *ndev, u8 status)
{
        struct nct6694_canfd_priv *priv = netdev_priv(ndev);
        enum can_state new_state, rx_state, tx_state;
        struct can_berr_counter bec;
        struct can_frame *cf;
        struct sk_buff *skb;

        nct6694_canfd_get_berr_counter(ndev, &bec);
        can_state_get_by_berr_counter(ndev, &bec, &tx_state, &rx_state);

        new_state = max(tx_state, rx_state);

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

        skb = alloc_can_err_skb(ndev, &cf);

        can_change_state(ndev, cf, tx_state, rx_state);

        if (new_state == CAN_STATE_BUS_OFF) {
                can_bus_off(ndev);
        } else if (cf) {
                cf->can_id |= CAN_ERR_CNT;
                cf->data[6] = bec.txerr;
                cf->data[7] = bec.rxerr;
        }

        if (skb)
                nct6694_canfd_rx_offload(&priv->offload, skb);
}

static void nct6694_canfd_handle_bus_err(struct net_device *ndev, u8 bus_err)
{
        struct nct6694_canfd_priv *priv = netdev_priv(ndev);
        struct can_frame *cf;
        struct sk_buff *skb;

        priv->can.can_stats.bus_error++;

        skb = alloc_can_err_skb(ndev, &cf);
        if (cf)
                cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;

        switch (bus_err) {
        case NCT6694_CANFD_EVT_ERR_CRC_ERROR:
                netdev_dbg(ndev, "CRC error\n");
                ndev->stats.rx_errors++;
                if (cf)
                        cf->data[3] |= CAN_ERR_PROT_LOC_CRC_SEQ;
                break;

        case NCT6694_CANFD_EVT_ERR_STUFF_ERROR:
                netdev_dbg(ndev, "Stuff error\n");
                ndev->stats.rx_errors++;
                if (cf)
                        cf->data[2] |= CAN_ERR_PROT_STUFF;
                break;

        case NCT6694_CANFD_EVT_ERR_ACK_ERROR:
                netdev_dbg(ndev, "Ack error\n");
                ndev->stats.tx_errors++;
                if (cf) {
                        cf->can_id |= CAN_ERR_ACK;
                        cf->data[2] |= CAN_ERR_PROT_TX;
                }
                break;

        case NCT6694_CANFD_EVT_ERR_FORM_ERROR:
                netdev_dbg(ndev, "Form error\n");
                ndev->stats.rx_errors++;
                if (cf)
                        cf->data[2] |= CAN_ERR_PROT_FORM;
                break;

        case NCT6694_CANFD_EVT_ERR_BIT_ERROR:
                netdev_dbg(ndev, "Bit error\n");
                ndev->stats.tx_errors++;
                if (cf)
                        cf->data[2] |= CAN_ERR_PROT_TX | CAN_ERR_PROT_BIT;
                break;

        default:
                break;
        }

        if (skb)
                nct6694_canfd_rx_offload(&priv->offload, skb);
}

static void nct6694_canfd_handle_tx(struct net_device *ndev)
{
        struct nct6694_canfd_priv *priv = netdev_priv(ndev);
        struct net_device_stats *stats = &ndev->stats;

        stats->tx_bytes += can_rx_offload_get_echo_skb_queue_tail(&priv->offload,
                                                                  0, NULL);
        stats->tx_packets++;
        netif_wake_queue(ndev);
}

static irqreturn_t nct6694_canfd_irq(int irq, void *data)
{
        struct net_device *ndev = data;
        struct nct6694_canfd_priv *priv = netdev_priv(ndev);
        struct nct6694_canfd_event *event = &priv->event[ndev->dev_port];
        const struct nct6694_cmd_header cmd_hd = {
                .mod = NCT6694_CANFD_MOD,
                .cmd = NCT6694_CANFD_EVENT,
                .sel = NCT6694_CANFD_EVENT_SEL(ndev->dev_port, NCT6694_CANFD_EVENT_MASK),
                .len = cpu_to_le16(sizeof(priv->event))
        };
        irqreturn_t handled = IRQ_NONE;
        int ret;

        ret = nct6694_read_msg(priv->nct6694, &cmd_hd, priv->event);
        if (ret < 0)
                return handled;

        if (event->rx_evt & NCT6694_CANFD_EVT_RX_DATA_IN) {
                nct6694_canfd_handle_rx(ndev, event->rx_evt);
                handled = IRQ_HANDLED;
        }

        if (event->rx_evt & NCT6694_CANFD_EVT_RX_DATA_LOST) {
                nct6694_canfd_handle_lost_msg(ndev);
                handled = IRQ_HANDLED;
        }

        if (event->status) {
                nct6694_canfd_handle_state_change(ndev, event->status);
                handled = IRQ_HANDLED;
        }

        if (event->err != NCT6694_CANFD_EVT_ERR_NO_ERROR) {
                if (priv->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING)
                        nct6694_canfd_handle_bus_err(ndev, event->err);
                handled = IRQ_HANDLED;
        }

        if (event->tx_evt & NCT6694_CANFD_EVT_TX_FIFO_EMPTY) {
                nct6694_canfd_handle_tx(ndev);
                handled = IRQ_HANDLED;
        }

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

        priv->bec.rxerr = event->rec;
        priv->bec.txerr = event->tec;

        return handled;
}

static void nct6694_canfd_tx_work(struct work_struct *work)
{
        struct nct6694_canfd_priv *priv = container_of(work,
                                                       struct nct6694_canfd_priv,
                                                       tx_work);
        struct nct6694_canfd_frame *frame = &priv->tx;
        struct net_device *ndev = priv->ndev;
        struct net_device_stats *stats = &ndev->stats;
        struct sk_buff *skb = priv->can.echo_skb[0];
        static const struct nct6694_cmd_header cmd_hd = {
                .mod = NCT6694_CANFD_MOD,
                .cmd = NCT6694_CANFD_DELIVER,
                .sel = NCT6694_CANFD_DELIVER_SEL(1),
                .len = cpu_to_le16(sizeof(*frame))
        };
        u32 txid;
        int err;

        memset(frame, 0, sizeof(*frame));

        frame->tag = NCT6694_CANFD_FRAME_TAG(ndev->dev_port);

        if (can_is_canfd_skb(skb)) {
                struct canfd_frame *cfd = (struct canfd_frame *)skb->data;

                if (cfd->flags & CANFD_BRS)
                        frame->flag |= NCT6694_CANFD_FRAME_FLAG_BRS;

                if (cfd->can_id & CAN_EFF_FLAG) {
                        txid = cfd->can_id & CAN_EFF_MASK;
                        frame->flag |= NCT6694_CANFD_FRAME_FLAG_EFF;
                } else {
                        txid = cfd->can_id & CAN_SFF_MASK;
                }
                frame->flag |= NCT6694_CANFD_FRAME_FLAG_FD;
                frame->id = cpu_to_le32(txid);
                frame->length = canfd_sanitize_len(cfd->len);

                memcpy(frame->data, cfd->data, frame->length);
        } else {
                struct can_frame *cf = (struct can_frame *)skb->data;

                if (cf->can_id & CAN_EFF_FLAG) {
                        txid = cf->can_id & CAN_EFF_MASK;
                        frame->flag |= NCT6694_CANFD_FRAME_FLAG_EFF;
                } else {
                        txid = cf->can_id & CAN_SFF_MASK;
                }

                if (cf->can_id & CAN_RTR_FLAG)
                        frame->flag |= NCT6694_CANFD_FRAME_FLAG_RTR;
                else
                        memcpy(frame->data, cf->data, cf->len);

                frame->id = cpu_to_le32(txid);
                frame->length = cf->len;
        }

        err = nct6694_write_msg(priv->nct6694, &cmd_hd, frame);
        if (err) {
                can_free_echo_skb(ndev, 0, NULL);
                stats->tx_dropped++;
                stats->tx_errors++;
                netif_wake_queue(ndev);
        }
}

static netdev_tx_t nct6694_canfd_start_xmit(struct sk_buff *skb,
                                            struct net_device *ndev)
{
        struct nct6694_canfd_priv *priv = netdev_priv(ndev);

        if (can_dev_dropped_skb(ndev, skb))
                return NETDEV_TX_OK;

        netif_stop_queue(ndev);
        can_put_echo_skb(skb, ndev, 0, 0);
        queue_work(priv->wq, &priv->tx_work);

        return NETDEV_TX_OK;
}

static int nct6694_canfd_start(struct net_device *ndev)
{
        struct nct6694_canfd_priv *priv = netdev_priv(ndev);
        const struct can_bittiming *n_bt = &priv->can.bittiming;
        const struct can_bittiming *d_bt = &priv->can.fd.data_bittiming;
        struct nct6694_canfd_setting *setting __free(kfree) = NULL;
        const struct nct6694_cmd_header cmd_hd = {
                .mod = NCT6694_CANFD_MOD,
                .cmd = NCT6694_CANFD_SETTING,
                .sel = ndev->dev_port,
                .len = cpu_to_le16(sizeof(*setting))
        };
        u32 en_tdc;
        int ret;

        setting = kzalloc_obj(*setting);
        if (!setting)
                return -ENOMEM;

        if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
                setting->ctrl1 |= cpu_to_le16(NCT6694_CANFD_SETTING_CTRL1_MON);

        if (priv->can.ctrlmode & CAN_CTRLMODE_FD_NON_ISO)
                setting->ctrl1 |= cpu_to_le16(NCT6694_CANFD_SETTING_CTRL1_NISO);

        if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK)
                setting->ctrl1 |= cpu_to_le16(NCT6694_CANFD_SETTING_CTRL1_LBCK);

        /* Disable clock divider */
        setting->ctrl2 = 0;

        setting->nbtp = cpu_to_le32(FIELD_PREP(NCT6694_CANFD_SETTING_NBTP_NSJW,
                                               n_bt->sjw - 1) |
                                    FIELD_PREP(NCT6694_CANFD_SETTING_NBTP_NBRP,
                                               n_bt->brp - 1) |
                                    FIELD_PREP(NCT6694_CANFD_SETTING_NBTP_NTSEG2,
                                               n_bt->phase_seg2 - 1) |
                                    FIELD_PREP(NCT6694_CANFD_SETTING_NBTP_NTSEG1,
                                               n_bt->prop_seg + n_bt->phase_seg1 - 1));

        if (d_bt->brp <= 2)
                en_tdc = NCT6694_CANFD_SETTING_DBTP_TDC;
        else
                en_tdc = 0;

        setting->dbtp = cpu_to_le32(FIELD_PREP(NCT6694_CANFD_SETTING_DBTP_DSJW,
                                               d_bt->sjw - 1) |
                                    FIELD_PREP(NCT6694_CANFD_SETTING_DBTP_DBRP,
                                               d_bt->brp - 1) |
                                    FIELD_PREP(NCT6694_CANFD_SETTING_DBTP_DTSEG2,
                                               d_bt->phase_seg2 - 1) |
                                    FIELD_PREP(NCT6694_CANFD_SETTING_DBTP_DTSEG1,
                                               d_bt->prop_seg + d_bt->phase_seg1 - 1) |
                                    en_tdc);

        setting->active = NCT6694_CANFD_SETTING_ACTIVE_CTRL1 |
                          NCT6694_CANFD_SETTING_ACTIVE_CTRL2 |
                          NCT6694_CANFD_SETTING_ACTIVE_NBTP_DBTP;

        ret = nct6694_write_msg(priv->nct6694, &cmd_hd, setting);
        if (ret)
                return ret;

        priv->can.state = CAN_STATE_ERROR_ACTIVE;

        return 0;
}

static void nct6694_canfd_stop(struct net_device *ndev)
{
        struct nct6694_canfd_priv *priv = netdev_priv(ndev);
        struct nct6694_canfd_setting *setting __free(kfree) = NULL;
        const struct nct6694_cmd_header cmd_hd = {
                .mod = NCT6694_CANFD_MOD,
                .cmd = NCT6694_CANFD_SETTING,
                .sel = ndev->dev_port,
                .len = cpu_to_le16(sizeof(*setting))
        };

        /* The NCT6694 cannot be stopped. To ensure safe operation and avoid
         * interference, the control mode is set to Listen-Only mode. This
         * mode allows the device to monitor bus activity without actively
         * participating in communication.
         */
        setting = kzalloc_obj(*setting);
        if (!setting)
                return;

        nct6694_read_msg(priv->nct6694, &cmd_hd, setting);
        setting->ctrl1 = cpu_to_le16(NCT6694_CANFD_SETTING_CTRL1_MON);
        setting->active = NCT6694_CANFD_SETTING_ACTIVE_CTRL1;
        nct6694_write_msg(priv->nct6694, &cmd_hd, setting);

        priv->can.state = CAN_STATE_STOPPED;
}

static int nct6694_canfd_close(struct net_device *ndev)
{
        struct nct6694_canfd_priv *priv = netdev_priv(ndev);

        netif_stop_queue(ndev);
        nct6694_canfd_stop(ndev);
        destroy_workqueue(priv->wq);
        free_irq(ndev->irq, ndev);
        can_rx_offload_disable(&priv->offload);
        close_candev(ndev);
        return 0;
}

static int nct6694_canfd_set_mode(struct net_device *ndev, enum can_mode mode)
{
        int ret;

        switch (mode) {
        case CAN_MODE_START:
                ret = nct6694_canfd_start(ndev);
                if (ret)
                        return ret;

                netif_wake_queue(ndev);
                break;

        default:
                return -EOPNOTSUPP;
        }

        return ret;
}

static int nct6694_canfd_open(struct net_device *ndev)
{
        struct nct6694_canfd_priv *priv = netdev_priv(ndev);
        int ret;

        ret = open_candev(ndev);
        if (ret)
                return ret;

        can_rx_offload_enable(&priv->offload);

        ret = request_threaded_irq(ndev->irq, NULL,
                                   nct6694_canfd_irq, IRQF_ONESHOT,
                                   "nct6694_canfd", ndev);
        if (ret) {
                netdev_err(ndev, "Failed to request IRQ\n");
                goto can_rx_offload_disable;
        }

        priv->wq = alloc_ordered_workqueue("%s-nct6694_wq",
                                           WQ_FREEZABLE | WQ_MEM_RECLAIM,
                                           ndev->name);
        if (!priv->wq) {
                ret = -ENOMEM;
                goto free_irq;
        }

        ret = nct6694_canfd_start(ndev);
        if (ret)
                goto destroy_wq;

        netif_start_queue(ndev);

        return 0;

destroy_wq:
        destroy_workqueue(priv->wq);
free_irq:
        free_irq(ndev->irq, ndev);
can_rx_offload_disable:
        can_rx_offload_disable(&priv->offload);
        close_candev(ndev);
        return ret;
}

static const struct net_device_ops nct6694_canfd_netdev_ops = {
        .ndo_open = nct6694_canfd_open,
        .ndo_stop = nct6694_canfd_close,
        .ndo_start_xmit = nct6694_canfd_start_xmit,
};

static const struct ethtool_ops nct6694_canfd_ethtool_ops = {
        .get_ts_info = ethtool_op_get_ts_info,
};

static int nct6694_canfd_get_clock(struct nct6694_canfd_priv *priv)
{
        struct nct6694_canfd_information *info __free(kfree) = NULL;
        static const struct nct6694_cmd_header cmd_hd = {
                .mod = NCT6694_CANFD_MOD,
                .cmd = NCT6694_CANFD_INFORMATION,
                .sel = NCT6694_CANFD_INFORMATION_SEL,
                .len = cpu_to_le16(sizeof(*info))
        };
        int ret;

        info = kzalloc_obj(*info);
        if (!info)
                return -ENOMEM;

        ret = nct6694_read_msg(priv->nct6694, &cmd_hd, info);
        if (ret)
                return ret;

        return le32_to_cpu(info->can_clk);
}

static int nct6694_canfd_probe(struct platform_device *pdev)
{
        struct nct6694 *nct6694 = dev_get_drvdata(pdev->dev.parent);
        struct nct6694_canfd_priv *priv;
        struct net_device *ndev;
        int port, irq, ret, can_clk;

        port = ida_alloc(&nct6694->canfd_ida, GFP_KERNEL);
        if (port < 0)
                return port;

        irq = irq_create_mapping(nct6694->domain,
                                 NCT6694_IRQ_CAN0 + port);
        if (!irq) {
                ret = -EINVAL;
                goto free_ida;
        }

        ndev = alloc_candev(sizeof(struct nct6694_canfd_priv), 1);
        if (!ndev) {
                ret = -ENOMEM;
                goto dispose_irq;
        }

        ndev->irq = irq;
        ndev->flags |= IFF_ECHO;
        ndev->dev_port = port;
        ndev->netdev_ops = &nct6694_canfd_netdev_ops;
        ndev->ethtool_ops = &nct6694_canfd_ethtool_ops;

        priv = netdev_priv(ndev);
        priv->nct6694 = nct6694;
        priv->ndev = ndev;

        can_clk = nct6694_canfd_get_clock(priv);
        if (can_clk < 0) {
                ret = dev_err_probe(&pdev->dev, can_clk,
                                    "Failed to get clock\n");
                goto free_candev;
        }

        INIT_WORK(&priv->tx_work, nct6694_canfd_tx_work);

        priv->can.clock.freq = can_clk;
        priv->can.bittiming_const = &nct6694_canfd_bittiming_nominal_const;
        priv->can.fd.data_bittiming_const = &nct6694_canfd_bittiming_data_const;
        priv->can.do_set_mode = nct6694_canfd_set_mode;
        priv->can.do_get_berr_counter = nct6694_canfd_get_berr_counter;
        priv->can.ctrlmode_supported = CAN_CTRLMODE_LOOPBACK |
                CAN_CTRLMODE_LISTENONLY | CAN_CTRLMODE_BERR_REPORTING |
                CAN_CTRLMODE_FD_NON_ISO;

        ret = can_set_static_ctrlmode(ndev, CAN_CTRLMODE_FD);
        if (ret)
                goto free_candev;

        ret = can_rx_offload_add_manual(ndev, &priv->offload,
                                        NCT6694_NAPI_WEIGHT);
        if (ret) {
                dev_err_probe(&pdev->dev, ret, "Failed to add rx_offload\n");
                goto free_candev;
        }

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

        ret = register_candev(priv->ndev);
        if (ret)
                goto rx_offload_del;

        return 0;

rx_offload_del:
        can_rx_offload_del(&priv->offload);
free_candev:
        free_candev(ndev);
dispose_irq:
        irq_dispose_mapping(irq);
free_ida:
        ida_free(&nct6694->canfd_ida, port);
        return ret;
}

static void nct6694_canfd_remove(struct platform_device *pdev)
{
        struct nct6694_canfd_priv *priv = platform_get_drvdata(pdev);
        struct nct6694 *nct6694 = priv->nct6694;
        struct net_device *ndev = priv->ndev;
        int port = ndev->dev_port;
        int irq = ndev->irq;

        unregister_candev(ndev);
        can_rx_offload_del(&priv->offload);
        free_candev(ndev);
        irq_dispose_mapping(irq);
        ida_free(&nct6694->canfd_ida, port);
}

static struct platform_driver nct6694_canfd_driver = {
        .driver = {
                .name   = DEVICE_NAME,
        },
        .probe          = nct6694_canfd_probe,
        .remove         = nct6694_canfd_remove,
};

module_platform_driver(nct6694_canfd_driver);

MODULE_DESCRIPTION("USB-CAN FD driver for NCT6694");
MODULE_AUTHOR("Ming Yu <tmyu0@nuvoton.com>");
MODULE_LICENSE("GPL");