// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Freescale QMC HDLC Device Driver
 *
 * Copyright 2023 CS GROUP France
 *
 * Author: Herve Codina <herve.codina@bootlin.com>
 */

#include <linux/array_size.h>
#include <linux/bug.h>
#include <linux/cleanup.h>
#include <linux/bitmap.h>
#include <linux/dma-mapping.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/framer/framer.h>
#include <linux/hdlc.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/types.h>

#include <soc/fsl/qe/qmc.h>

struct qmc_hdlc_desc {
        struct net_device *netdev;
        struct sk_buff *skb; /* NULL if the descriptor is not in use */
        dma_addr_t dma_addr;
        size_t dma_size;
};

struct qmc_hdlc {
        struct device *dev;
        struct qmc_chan *qmc_chan;
        struct net_device *netdev;
        struct framer *framer;
        struct mutex carrier_lock; /* Protect carrier detection */
        struct notifier_block nb;
        bool is_crc32;
        spinlock_t tx_lock; /* Protect tx descriptors */
        struct qmc_hdlc_desc tx_descs[8];
        unsigned int tx_out;
        struct qmc_hdlc_desc rx_descs[4];
        u32 slot_map;
};

static struct qmc_hdlc *netdev_to_qmc_hdlc(struct net_device *netdev)
{
        return dev_to_hdlc(netdev)->priv;
}

static int qmc_hdlc_framer_set_carrier(struct qmc_hdlc *qmc_hdlc)
{
        struct framer_status framer_status;
        int ret;

        if (!qmc_hdlc->framer)
                return 0;

        guard(mutex)(&qmc_hdlc->carrier_lock);

        ret = framer_get_status(qmc_hdlc->framer, &framer_status);
        if (ret) {
                dev_err(qmc_hdlc->dev, "get framer status failed (%d)\n", ret);
                return ret;
        }
        if (framer_status.link_is_on)
                netif_carrier_on(qmc_hdlc->netdev);
        else
                netif_carrier_off(qmc_hdlc->netdev);

        return 0;
}

static int qmc_hdlc_framer_notifier(struct notifier_block *nb, unsigned long action,
                                    void *data)
{
        struct qmc_hdlc *qmc_hdlc = container_of(nb, struct qmc_hdlc, nb);
        int ret;

        if (action != FRAMER_EVENT_STATUS)
                return NOTIFY_DONE;

        ret = qmc_hdlc_framer_set_carrier(qmc_hdlc);
        return ret ? NOTIFY_DONE : NOTIFY_OK;
}

static int qmc_hdlc_framer_start(struct qmc_hdlc *qmc_hdlc)
{
        struct framer_status framer_status;
        int ret;

        if (!qmc_hdlc->framer)
                return 0;

        ret = framer_power_on(qmc_hdlc->framer);
        if (ret) {
                dev_err(qmc_hdlc->dev, "framer power-on failed (%d)\n", ret);
                return ret;
        }

        /* Be sure that get_status is supported */
        ret = framer_get_status(qmc_hdlc->framer, &framer_status);
        if (ret) {
                dev_err(qmc_hdlc->dev, "get framer status failed (%d)\n", ret);
                goto framer_power_off;
        }

        qmc_hdlc->nb.notifier_call = qmc_hdlc_framer_notifier;
        ret = framer_notifier_register(qmc_hdlc->framer, &qmc_hdlc->nb);
        if (ret) {
                dev_err(qmc_hdlc->dev, "framer notifier register failed (%d)\n", ret);
                goto framer_power_off;
        }

        return 0;

framer_power_off:
        framer_power_off(qmc_hdlc->framer);
        return ret;
}

static void qmc_hdlc_framer_stop(struct qmc_hdlc *qmc_hdlc)
{
        if (!qmc_hdlc->framer)
                return;

        framer_notifier_unregister(qmc_hdlc->framer, &qmc_hdlc->nb);
        framer_power_off(qmc_hdlc->framer);
}

static int qmc_hdlc_framer_set_iface(struct qmc_hdlc *qmc_hdlc, int if_iface,
                                     const te1_settings *te1)
{
        struct framer_config config;
        int ret;

        if (!qmc_hdlc->framer)
                return 0;

        ret = framer_get_config(qmc_hdlc->framer, &config);
        if (ret)
                return ret;

        switch (if_iface) {
        case IF_IFACE_E1:
                config.iface = FRAMER_IFACE_E1;
                break;
        case IF_IFACE_T1:
                config.iface = FRAMER_IFACE_T1;
                break;
        default:
                return -EINVAL;
        }

        switch (te1->clock_type) {
        case CLOCK_DEFAULT:
                /* Keep current value */
                break;
        case CLOCK_EXT:
                config.clock_type = FRAMER_CLOCK_EXT;
                break;
        case CLOCK_INT:
                config.clock_type = FRAMER_CLOCK_INT;
                break;
        default:
                return -EINVAL;
        }
        config.line_clock_rate = te1->clock_rate;

        return framer_set_config(qmc_hdlc->framer, &config);
}

static int qmc_hdlc_framer_get_iface(struct qmc_hdlc *qmc_hdlc, int *if_iface, te1_settings *te1)
{
        struct framer_config config;
        int ret;

        if (!qmc_hdlc->framer) {
                *if_iface = IF_IFACE_E1;
                return 0;
        }

        ret = framer_get_config(qmc_hdlc->framer, &config);
        if (ret)
                return ret;

        switch (config.iface) {
        case FRAMER_IFACE_E1:
                *if_iface = IF_IFACE_E1;
                break;
        case FRAMER_IFACE_T1:
                *if_iface = IF_IFACE_T1;
                break;
        }

        if (!te1)
                return 0; /* Only iface type requested */

        switch (config.clock_type) {
        case FRAMER_CLOCK_EXT:
                te1->clock_type = CLOCK_EXT;
                break;
        case FRAMER_CLOCK_INT:
                te1->clock_type = CLOCK_INT;
                break;
        default:
                return -EINVAL;
        }
        te1->clock_rate = config.line_clock_rate;
        return 0;
}

static int qmc_hdlc_framer_init(struct qmc_hdlc *qmc_hdlc)
{
        int ret;

        if (!qmc_hdlc->framer)
                return 0;

        ret = framer_init(qmc_hdlc->framer);
        if (ret) {
                dev_err(qmc_hdlc->dev, "framer init failed (%d)\n", ret);
                return ret;
        }

        return 0;
}

static void qmc_hdlc_framer_exit(struct qmc_hdlc *qmc_hdlc)
{
        if (!qmc_hdlc->framer)
                return;

        framer_exit(qmc_hdlc->framer);
}

static int qmc_hdlc_recv_queue(struct qmc_hdlc *qmc_hdlc, struct qmc_hdlc_desc *desc, size_t size);

#define QMC_HDLC_RX_ERROR_FLAGS                         \
        (QMC_RX_FLAG_HDLC_OVF | QMC_RX_FLAG_HDLC_UNA |  \
         QMC_RX_FLAG_HDLC_CRC | QMC_RX_FLAG_HDLC_ABORT)

static void qmc_hcld_recv_complete(void *context, size_t length, unsigned int flags)
{
        struct qmc_hdlc_desc *desc = context;
        struct net_device *netdev;
        struct qmc_hdlc *qmc_hdlc;
        size_t crc_size;
        int ret;

        netdev = desc->netdev;
        qmc_hdlc = netdev_to_qmc_hdlc(netdev);

        dma_unmap_single(qmc_hdlc->dev, desc->dma_addr, desc->dma_size, DMA_FROM_DEVICE);

        if (flags & QMC_HDLC_RX_ERROR_FLAGS) {
                netdev->stats.rx_errors++;
                if (flags & QMC_RX_FLAG_HDLC_OVF) /* Data overflow */
                        netdev->stats.rx_over_errors++;
                if (flags & QMC_RX_FLAG_HDLC_UNA) /* bits received not multiple of 8 */
                        netdev->stats.rx_frame_errors++;
                if (flags & QMC_RX_FLAG_HDLC_ABORT) /* Received an abort sequence */
                        netdev->stats.rx_frame_errors++;
                if (flags & QMC_RX_FLAG_HDLC_CRC) /* CRC error */
                        netdev->stats.rx_crc_errors++;
                kfree_skb(desc->skb);
                goto re_queue;
        }

        /* Discard the CRC */
        crc_size = qmc_hdlc->is_crc32 ? 4 : 2;
        if (length < crc_size) {
                netdev->stats.rx_length_errors++;
                kfree_skb(desc->skb);
                goto re_queue;
        }
        length -= crc_size;

        netdev->stats.rx_packets++;
        netdev->stats.rx_bytes += length;

        skb_put(desc->skb, length);
        desc->skb->protocol = hdlc_type_trans(desc->skb, netdev);
        netif_rx(desc->skb);

re_queue:
        /* Re-queue a transfer using the same descriptor */
        ret = qmc_hdlc_recv_queue(qmc_hdlc, desc, desc->dma_size);
        if (ret) {
                dev_err(qmc_hdlc->dev, "queue recv desc failed (%d)\n", ret);
                netdev->stats.rx_errors++;
        }
}

static int qmc_hdlc_recv_queue(struct qmc_hdlc *qmc_hdlc, struct qmc_hdlc_desc *desc, size_t size)
{
        int ret;

        desc->skb = dev_alloc_skb(size);
        if (!desc->skb)
                return -ENOMEM;

        desc->dma_size = size;
        desc->dma_addr = dma_map_single(qmc_hdlc->dev, desc->skb->data,
                                        desc->dma_size, DMA_FROM_DEVICE);
        ret = dma_mapping_error(qmc_hdlc->dev, desc->dma_addr);
        if (ret)
                goto free_skb;

        ret = qmc_chan_read_submit(qmc_hdlc->qmc_chan, desc->dma_addr, desc->dma_size,
                                   qmc_hcld_recv_complete, desc);
        if (ret)
                goto dma_unmap;

        return 0;

dma_unmap:
        dma_unmap_single(qmc_hdlc->dev, desc->dma_addr, desc->dma_size, DMA_FROM_DEVICE);
free_skb:
        kfree_skb(desc->skb);
        desc->skb = NULL;
        return ret;
}

static void qmc_hdlc_xmit_complete(void *context)
{
        struct qmc_hdlc_desc *desc = context;
        struct net_device *netdev;
        struct qmc_hdlc *qmc_hdlc;
        struct sk_buff *skb;

        netdev = desc->netdev;
        qmc_hdlc = netdev_to_qmc_hdlc(netdev);

        scoped_guard(spinlock_irqsave, &qmc_hdlc->tx_lock) {
                dma_unmap_single(qmc_hdlc->dev, desc->dma_addr, desc->dma_size, DMA_TO_DEVICE);
                skb = desc->skb;
                desc->skb = NULL; /* Release the descriptor */
                if (netif_queue_stopped(netdev))
                        netif_wake_queue(netdev);
        }

        netdev->stats.tx_packets++;
        netdev->stats.tx_bytes += skb->len;

        dev_consume_skb_any(skb);
}

static int qmc_hdlc_xmit_queue(struct qmc_hdlc *qmc_hdlc, struct qmc_hdlc_desc *desc)
{
        int ret;

        desc->dma_addr = dma_map_single(qmc_hdlc->dev, desc->skb->data,
                                        desc->dma_size, DMA_TO_DEVICE);
        ret = dma_mapping_error(qmc_hdlc->dev, desc->dma_addr);
        if (ret) {
                dev_err(qmc_hdlc->dev, "failed to map skb\n");
                return ret;
        }

        ret = qmc_chan_write_submit(qmc_hdlc->qmc_chan, desc->dma_addr, desc->dma_size,
                                    qmc_hdlc_xmit_complete, desc);
        if (ret) {
                dma_unmap_single(qmc_hdlc->dev, desc->dma_addr, desc->dma_size, DMA_TO_DEVICE);
                dev_err(qmc_hdlc->dev, "qmc chan write returns %d\n", ret);
                return ret;
        }

        return 0;
}

static netdev_tx_t qmc_hdlc_xmit(struct sk_buff *skb, struct net_device *netdev)
{
        struct qmc_hdlc *qmc_hdlc = netdev_to_qmc_hdlc(netdev);
        struct qmc_hdlc_desc *desc;
        int err;

        guard(spinlock_irqsave)(&qmc_hdlc->tx_lock);

        desc = &qmc_hdlc->tx_descs[qmc_hdlc->tx_out];
        if (WARN_ONCE(desc->skb, "No tx descriptors available\n")) {
                /* Should never happen.
                 * Previous xmit should have already stopped the queue.
                 */
                netif_stop_queue(netdev);
                return NETDEV_TX_BUSY;
        }

        desc->netdev = netdev;
        desc->dma_size = skb->len;
        desc->skb = skb;
        err = qmc_hdlc_xmit_queue(qmc_hdlc, desc);
        if (err) {
                desc->skb = NULL; /* Release the descriptor */
                if (err == -EBUSY) {
                        netif_stop_queue(netdev);
                        return NETDEV_TX_BUSY;
                }
                dev_kfree_skb(skb);
                netdev->stats.tx_dropped++;
                return NETDEV_TX_OK;
        }

        qmc_hdlc->tx_out = (qmc_hdlc->tx_out + 1) % ARRAY_SIZE(qmc_hdlc->tx_descs);

        if (qmc_hdlc->tx_descs[qmc_hdlc->tx_out].skb)
                netif_stop_queue(netdev);

        return NETDEV_TX_OK;
}

static int qmc_hdlc_xlate_slot_map(struct qmc_hdlc *qmc_hdlc,
                                   u32 slot_map, struct qmc_chan_ts_info *ts_info)
{
        DECLARE_BITMAP(ts_mask_avail, 64);
        DECLARE_BITMAP(ts_mask, 64);
        DECLARE_BITMAP(map, 64);

        /* Tx and Rx available masks must be identical */
        if (ts_info->rx_ts_mask_avail != ts_info->tx_ts_mask_avail) {
                dev_err(qmc_hdlc->dev, "tx and rx available timeslots mismatch (0x%llx, 0x%llx)\n",
                        ts_info->rx_ts_mask_avail, ts_info->tx_ts_mask_avail);
                return -EINVAL;
        }

        bitmap_from_u64(ts_mask_avail, ts_info->rx_ts_mask_avail);
        bitmap_from_u64(map, slot_map);
        bitmap_scatter(ts_mask, map, ts_mask_avail, 64);

        if (bitmap_weight(ts_mask, 64) != bitmap_weight(map, 64)) {
                dev_err(qmc_hdlc->dev, "Cannot translate timeslots %64pb -> (%64pb, %64pb)\n",
                        map, ts_mask_avail, ts_mask);
                return -EINVAL;
        }

        bitmap_to_arr64(&ts_info->tx_ts_mask, ts_mask, 64);
        ts_info->rx_ts_mask = ts_info->tx_ts_mask;
        return 0;
}

static int qmc_hdlc_xlate_ts_info(struct qmc_hdlc *qmc_hdlc,
                                  const struct qmc_chan_ts_info *ts_info, u32 *slot_map)
{
        DECLARE_BITMAP(ts_mask_avail, 64);
        DECLARE_BITMAP(ts_mask, 64);
        DECLARE_BITMAP(map, 64);
        u32 slot_array[2];

        /* Tx and Rx masks and available masks must be identical */
        if (ts_info->rx_ts_mask_avail != ts_info->tx_ts_mask_avail) {
                dev_err(qmc_hdlc->dev, "tx and rx available timeslots mismatch (0x%llx, 0x%llx)\n",
                        ts_info->rx_ts_mask_avail, ts_info->tx_ts_mask_avail);
                return -EINVAL;
        }
        if (ts_info->rx_ts_mask != ts_info->tx_ts_mask) {
                dev_err(qmc_hdlc->dev, "tx and rx timeslots mismatch (0x%llx, 0x%llx)\n",
                        ts_info->rx_ts_mask, ts_info->tx_ts_mask);
                return -EINVAL;
        }

        bitmap_from_u64(ts_mask_avail, ts_info->rx_ts_mask_avail);
        bitmap_from_u64(ts_mask, ts_info->rx_ts_mask);
        bitmap_gather(map, ts_mask, ts_mask_avail, 64);

        if (bitmap_weight(ts_mask, 64) != bitmap_weight(map, 64)) {
                dev_err(qmc_hdlc->dev, "Cannot translate timeslots (%64pb, %64pb) -> %64pb\n",
                        ts_mask_avail, ts_mask, map);
                return -EINVAL;
        }

        bitmap_to_arr32(slot_array, map, 64);
        if (slot_array[1]) {
                dev_err(qmc_hdlc->dev, "Slot map out of 32bit (%64pb, %64pb) -> %64pb\n",
                        ts_mask_avail, ts_mask, map);
                return -EINVAL;
        }

        *slot_map = slot_array[0];
        return 0;
}

static int qmc_hdlc_set_iface(struct qmc_hdlc *qmc_hdlc, int if_iface, const te1_settings *te1)
{
        struct qmc_chan_ts_info ts_info;
        int ret;

        ret = qmc_chan_get_ts_info(qmc_hdlc->qmc_chan, &ts_info);
        if (ret) {
                dev_err(qmc_hdlc->dev, "get QMC channel ts info failed %d\n", ret);
                return ret;
        }
        ret = qmc_hdlc_xlate_slot_map(qmc_hdlc, te1->slot_map, &ts_info);
        if (ret)
                return ret;

        ret = qmc_chan_set_ts_info(qmc_hdlc->qmc_chan, &ts_info);
        if (ret) {
                dev_err(qmc_hdlc->dev, "set QMC channel ts info failed %d\n", ret);
                return ret;
        }

        qmc_hdlc->slot_map = te1->slot_map;

        ret = qmc_hdlc_framer_set_iface(qmc_hdlc, if_iface, te1);
        if (ret) {
                dev_err(qmc_hdlc->dev, "framer set iface failed %d\n", ret);
                return ret;
        }

        return 0;
}

static int qmc_hdlc_ioctl(struct net_device *netdev, struct if_settings *ifs)
{
        struct qmc_hdlc *qmc_hdlc = netdev_to_qmc_hdlc(netdev);
        te1_settings te1;
        int ret;

        switch (ifs->type) {
        case IF_GET_IFACE:
                if (ifs->size < sizeof(te1)) {
                        /* Retrieve type only */
                        ret = qmc_hdlc_framer_get_iface(qmc_hdlc, &ifs->type, NULL);
                        if (ret)
                                return ret;

                        if (!ifs->size)
                                return 0; /* only type requested */

                        ifs->size = sizeof(te1); /* data size wanted */
                        return -ENOBUFS;
                }

                memset(&te1, 0, sizeof(te1));

                /* Retrieve info from framer */
                ret = qmc_hdlc_framer_get_iface(qmc_hdlc, &ifs->type, &te1);
                if (ret)
                        return ret;

                /* Update slot_map */
                te1.slot_map = qmc_hdlc->slot_map;

                if (copy_to_user(ifs->ifs_ifsu.te1, &te1, sizeof(te1)))
                        return -EFAULT;
                return 0;

        case IF_IFACE_E1:
        case IF_IFACE_T1:
                if (!capable(CAP_NET_ADMIN))
                        return -EPERM;

                if (netdev->flags & IFF_UP)
                        return -EBUSY;

                if (copy_from_user(&te1, ifs->ifs_ifsu.te1, sizeof(te1)))
                        return -EFAULT;

                return qmc_hdlc_set_iface(qmc_hdlc, ifs->type, &te1);

        default:
                return hdlc_ioctl(netdev, ifs);
        }
}

static int qmc_hdlc_open(struct net_device *netdev)
{
        struct qmc_hdlc *qmc_hdlc = netdev_to_qmc_hdlc(netdev);
        struct qmc_chan_param chan_param;
        struct qmc_hdlc_desc *desc;
        int ret;
        int i;

        ret = qmc_hdlc_framer_start(qmc_hdlc);
        if (ret)
                return ret;

        ret = hdlc_open(netdev);
        if (ret)
                goto framer_stop;

        /* Update carrier */
        qmc_hdlc_framer_set_carrier(qmc_hdlc);

        chan_param.mode = QMC_HDLC;
        /* HDLC_MAX_MRU + 4 for the CRC
         * HDLC_MAX_MRU + 4 + 8 for the CRC and some extraspace needed by the QMC
         */
        chan_param.hdlc.max_rx_buf_size = HDLC_MAX_MRU + 4 + 8;
        chan_param.hdlc.max_rx_frame_size = HDLC_MAX_MRU + 4;
        chan_param.hdlc.is_crc32 = qmc_hdlc->is_crc32;
        ret = qmc_chan_set_param(qmc_hdlc->qmc_chan, &chan_param);
        if (ret) {
                dev_err(qmc_hdlc->dev, "failed to set param (%d)\n", ret);
                goto hdlc_close;
        }

        /* Queue as many recv descriptors as possible */
        for (i = 0; i < ARRAY_SIZE(qmc_hdlc->rx_descs); i++) {
                desc = &qmc_hdlc->rx_descs[i];

                desc->netdev = netdev;
                ret = qmc_hdlc_recv_queue(qmc_hdlc, desc, chan_param.hdlc.max_rx_buf_size);
                if (ret == -EBUSY && i != 0)
                        break; /* We use all the QMC chan capability */
                if (ret)
                        goto free_desc;
        }

        ret = qmc_chan_start(qmc_hdlc->qmc_chan, QMC_CHAN_ALL);
        if (ret) {
                dev_err(qmc_hdlc->dev, "qmc chan start failed (%d)\n", ret);
                goto free_desc;
        }

        netif_start_queue(netdev);

        return 0;

free_desc:
        qmc_chan_reset(qmc_hdlc->qmc_chan, QMC_CHAN_ALL);
        while (i--) {
                desc = &qmc_hdlc->rx_descs[i];
                dma_unmap_single(qmc_hdlc->dev, desc->dma_addr, desc->dma_size,
                                 DMA_FROM_DEVICE);
                kfree_skb(desc->skb);
                desc->skb = NULL;
        }
hdlc_close:
        hdlc_close(netdev);
framer_stop:
        qmc_hdlc_framer_stop(qmc_hdlc);
        return ret;
}

static int qmc_hdlc_close(struct net_device *netdev)
{
        struct qmc_hdlc *qmc_hdlc = netdev_to_qmc_hdlc(netdev);
        struct qmc_hdlc_desc *desc;
        int i;

        qmc_chan_stop(qmc_hdlc->qmc_chan, QMC_CHAN_ALL);
        qmc_chan_reset(qmc_hdlc->qmc_chan, QMC_CHAN_ALL);

        netif_stop_queue(netdev);

        for (i = 0; i < ARRAY_SIZE(qmc_hdlc->tx_descs); i++) {
                desc = &qmc_hdlc->tx_descs[i];
                if (!desc->skb)
                        continue;
                dma_unmap_single(qmc_hdlc->dev, desc->dma_addr, desc->dma_size,
                                 DMA_TO_DEVICE);
                kfree_skb(desc->skb);
                desc->skb = NULL;
        }

        for (i = 0; i < ARRAY_SIZE(qmc_hdlc->rx_descs); i++) {
                desc = &qmc_hdlc->rx_descs[i];
                if (!desc->skb)
                        continue;
                dma_unmap_single(qmc_hdlc->dev, desc->dma_addr, desc->dma_size,
                                 DMA_FROM_DEVICE);
                kfree_skb(desc->skb);
                desc->skb = NULL;
        }

        hdlc_close(netdev);
        qmc_hdlc_framer_stop(qmc_hdlc);
        return 0;
}

static int qmc_hdlc_attach(struct net_device *netdev, unsigned short encoding,
                           unsigned short parity)
{
        struct qmc_hdlc *qmc_hdlc = netdev_to_qmc_hdlc(netdev);

        if (encoding != ENCODING_NRZ)
                return -EINVAL;

        switch (parity) {
        case PARITY_CRC16_PR1_CCITT:
                qmc_hdlc->is_crc32 = false;
                break;
        case PARITY_CRC32_PR1_CCITT:
                qmc_hdlc->is_crc32 = true;
                break;
        default:
                dev_err(qmc_hdlc->dev, "unsupported parity %u\n", parity);
                return -EINVAL;
        }

        return 0;
}

static const struct net_device_ops qmc_hdlc_netdev_ops = {
        .ndo_open       = qmc_hdlc_open,
        .ndo_stop       = qmc_hdlc_close,
        .ndo_start_xmit = hdlc_start_xmit,
        .ndo_siocwandev = qmc_hdlc_ioctl,
};

static int qmc_hdlc_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct qmc_chan_ts_info ts_info;
        struct qmc_hdlc *qmc_hdlc;
        struct qmc_chan_info info;
        hdlc_device *hdlc;
        int ret;

        qmc_hdlc = devm_kzalloc(dev, sizeof(*qmc_hdlc), GFP_KERNEL);
        if (!qmc_hdlc)
                return -ENOMEM;

        qmc_hdlc->dev = dev;
        spin_lock_init(&qmc_hdlc->tx_lock);
        mutex_init(&qmc_hdlc->carrier_lock);

        qmc_hdlc->qmc_chan = devm_qmc_chan_get_bychild(dev, dev->of_node);
        if (IS_ERR(qmc_hdlc->qmc_chan))
                return dev_err_probe(dev, PTR_ERR(qmc_hdlc->qmc_chan),
                                     "get QMC channel failed\n");

        ret = qmc_chan_get_info(qmc_hdlc->qmc_chan, &info);
        if (ret)
                return dev_err_probe(dev, ret, "get QMC channel info failed\n");

        if (info.mode != QMC_HDLC)
                return dev_err_probe(dev, -EINVAL, "QMC chan mode %d is not QMC_HDLC\n",
                                     info.mode);

        ret = qmc_chan_get_ts_info(qmc_hdlc->qmc_chan, &ts_info);
        if (ret)
                return dev_err_probe(dev, ret, "get QMC channel ts info failed\n");

        ret = qmc_hdlc_xlate_ts_info(qmc_hdlc, &ts_info, &qmc_hdlc->slot_map);
        if (ret)
                return ret;

        qmc_hdlc->framer = devm_framer_optional_get(dev, "fsl,framer");
        if (IS_ERR(qmc_hdlc->framer))
                return PTR_ERR(qmc_hdlc->framer);

        ret = qmc_hdlc_framer_init(qmc_hdlc);
        if (ret)
                return ret;

        qmc_hdlc->netdev = alloc_hdlcdev(qmc_hdlc);
        if (!qmc_hdlc->netdev) {
                ret = -ENOMEM;
                goto framer_exit;
        }

        hdlc = dev_to_hdlc(qmc_hdlc->netdev);
        hdlc->attach = qmc_hdlc_attach;
        hdlc->xmit = qmc_hdlc_xmit;
        SET_NETDEV_DEV(qmc_hdlc->netdev, dev);
        qmc_hdlc->netdev->tx_queue_len = ARRAY_SIZE(qmc_hdlc->tx_descs);
        qmc_hdlc->netdev->netdev_ops = &qmc_hdlc_netdev_ops;
        ret = register_hdlc_device(qmc_hdlc->netdev);
        if (ret) {
                dev_err_probe(dev, ret, "failed to register hdlc device\n");
                goto free_netdev;
        }

        platform_set_drvdata(pdev, qmc_hdlc);
        return 0;

free_netdev:
        free_netdev(qmc_hdlc->netdev);
framer_exit:
        qmc_hdlc_framer_exit(qmc_hdlc);
        return ret;
}

static void qmc_hdlc_remove(struct platform_device *pdev)
{
        struct qmc_hdlc *qmc_hdlc = platform_get_drvdata(pdev);

        unregister_hdlc_device(qmc_hdlc->netdev);
        free_netdev(qmc_hdlc->netdev);
        qmc_hdlc_framer_exit(qmc_hdlc);
}

static const struct of_device_id qmc_hdlc_id_table[] = {
        { .compatible = "fsl,qmc-hdlc" },
        {} /* sentinel */
};
MODULE_DEVICE_TABLE(of, qmc_hdlc_id_table);

static struct platform_driver qmc_hdlc_driver = {
        .driver = {
                .name = "fsl-qmc-hdlc",
                .of_match_table = qmc_hdlc_id_table,
        },
        .probe = qmc_hdlc_probe,
        .remove = qmc_hdlc_remove,
};
module_platform_driver(qmc_hdlc_driver);

MODULE_AUTHOR("Herve Codina <herve.codina@bootlin.com>");
MODULE_DESCRIPTION("QMC HDLC driver");
MODULE_LICENSE("GPL");