// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2015, The Linux Foundation. All rights reserved.
 */

#include <linux/etherdevice.h>
#include <linux/bitfield.h>
#include <net/dsa.h>
#include <linux/dsa/tag_qca.h>

#include "tag.h"

#define QCA_NAME "qca"

static struct sk_buff *qca_tag_xmit(struct sk_buff *skb, struct net_device *dev)
{
        __be16 *phdr;
        u16 hdr;

        skb_push(skb, QCA_HDR_LEN);

        dsa_alloc_etype_header(skb, QCA_HDR_LEN);
        phdr = dsa_etype_header_pos_tx(skb);

        /* Set the version field, and set destination port information */
        hdr = FIELD_PREP(QCA_HDR_XMIT_VERSION, QCA_HDR_VERSION);
        hdr |= QCA_HDR_XMIT_FROM_CPU;
        hdr |= FIELD_PREP(QCA_HDR_XMIT_DP_BIT, dsa_xmit_port_mask(skb, dev));

        *phdr = htons(hdr);

        return skb;
}

static struct sk_buff *qca_tag_rcv(struct sk_buff *skb, struct net_device *dev)
{
        struct qca_tagger_data *tagger_data;
        struct dsa_port *dp = dev->dsa_ptr;
        struct dsa_switch *ds = dp->ds;
        u8 ver, pk_type;
        __be16 *phdr;
        int port;
        u16 hdr;

        BUILD_BUG_ON(sizeof(struct qca_mgmt_ethhdr) != QCA_HDR_MGMT_HEADER_LEN + QCA_HDR_LEN);

        tagger_data = ds->tagger_data;

        if (unlikely(!pskb_may_pull(skb, QCA_HDR_LEN)))
                return NULL;

        phdr = dsa_etype_header_pos_rx(skb);
        hdr = ntohs(*phdr);

        /* Make sure the version is correct */
        ver = FIELD_GET(QCA_HDR_RECV_VERSION, hdr);
        if (unlikely(ver != QCA_HDR_VERSION))
                return NULL;

        /* Get pk type */
        pk_type = FIELD_GET(QCA_HDR_RECV_TYPE, hdr);

        /* Ethernet mgmt read/write packet */
        if (pk_type == QCA_HDR_RECV_TYPE_RW_REG_ACK) {
                if (likely(tagger_data->rw_reg_ack_handler))
                        tagger_data->rw_reg_ack_handler(ds, skb);
                return NULL;
        }

        /* Ethernet MIB counter packet */
        if (pk_type == QCA_HDR_RECV_TYPE_MIB) {
                if (likely(tagger_data->mib_autocast_handler))
                        tagger_data->mib_autocast_handler(ds, skb);
                return NULL;
        }

        /* Get source port information */
        port = FIELD_GET(QCA_HDR_RECV_SOURCE_PORT, hdr);

        skb->dev = dsa_conduit_find_user(dev, 0, port);
        if (!skb->dev)
                return NULL;

        /* Remove QCA tag and recalculate checksum */
        skb_pull_rcsum(skb, QCA_HDR_LEN);
        dsa_strip_etype_header(skb, QCA_HDR_LEN);

        return skb;
}

static int qca_tag_connect(struct dsa_switch *ds)
{
        struct qca_tagger_data *tagger_data;

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

        ds->tagger_data = tagger_data;

        return 0;
}

static void qca_tag_disconnect(struct dsa_switch *ds)
{
        kfree(ds->tagger_data);
        ds->tagger_data = NULL;
}

static const struct dsa_device_ops qca_netdev_ops = {
        .name   = QCA_NAME,
        .proto  = DSA_TAG_PROTO_QCA,
        .connect = qca_tag_connect,
        .disconnect = qca_tag_disconnect,
        .xmit   = qca_tag_xmit,
        .rcv    = qca_tag_rcv,
        .needed_headroom = QCA_HDR_LEN,
        .promisc_on_conduit = true,
};

MODULE_DESCRIPTION("DSA tag driver for Qualcomm Atheros QCA8K switches");
MODULE_LICENSE("GPL");
MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_QCA, QCA_NAME);

module_dsa_tag_driver(qca_netdev_ops);