// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) ST-Ericsson AB 2010
 * Author:      Sjur Brendeland
 */

#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__

#include <linux/stddef.h>
#include <linux/slab.h>
#include <net/caif/caif_layer.h>
#include <net/caif/cfsrvl.h>
#include <net/caif/cfpkt.h>

#define VEI_PAYLOAD  0x00
#define VEI_CMD_BIT  0x80
#define VEI_FLOW_OFF 0x81
#define VEI_FLOW_ON  0x80
#define VEI_SET_PIN  0x82

#define container_obj(layr) container_of(layr, struct cfsrvl, layer)

static int cfvei_receive(struct cflayer *layr, struct cfpkt *pkt);
static int cfvei_transmit(struct cflayer *layr, struct cfpkt *pkt);

struct cflayer *cfvei_create(u8 channel_id, struct dev_info *dev_info)
{
        struct cfsrvl *vei = kzalloc_obj(struct cfsrvl, GFP_ATOMIC);
        if (!vei)
                return NULL;
        caif_assert(offsetof(struct cfsrvl, layer) == 0);
        cfsrvl_init(vei, channel_id, dev_info, true);
        vei->layer.receive = cfvei_receive;
        vei->layer.transmit = cfvei_transmit;
        snprintf(vei->layer.name, CAIF_LAYER_NAME_SZ, "vei%d", channel_id);
        return &vei->layer;
}

static int cfvei_receive(struct cflayer *layr, struct cfpkt *pkt)
{
        u8 cmd;
        int ret;
        caif_assert(layr->up != NULL);
        caif_assert(layr->receive != NULL);
        caif_assert(layr->ctrlcmd != NULL);


        if (cfpkt_extr_head(pkt, &cmd, 1) < 0) {
                pr_err("Packet is erroneous!\n");
                cfpkt_destroy(pkt);
                return -EPROTO;
        }
        switch (cmd) {
        case VEI_PAYLOAD:
                ret = layr->up->receive(layr->up, pkt);
                return ret;
        case VEI_FLOW_OFF:
                layr->ctrlcmd(layr, CAIF_CTRLCMD_FLOW_OFF_IND, 0);
                cfpkt_destroy(pkt);
                return 0;
        case VEI_FLOW_ON:
                layr->ctrlcmd(layr, CAIF_CTRLCMD_FLOW_ON_IND, 0);
                cfpkt_destroy(pkt);
                return 0;
        case VEI_SET_PIN:       /* SET RS232 PIN */
                cfpkt_destroy(pkt);
                return 0;
        default:                /* SET RS232 PIN */
                pr_warn("Unknown VEI control packet %d (0x%x)!\n", cmd, cmd);
                cfpkt_destroy(pkt);
                return -EPROTO;
        }
}

static int cfvei_transmit(struct cflayer *layr, struct cfpkt *pkt)
{
        u8 tmp = 0;
        struct caif_payload_info *info;
        int ret;
        struct cfsrvl *service = container_obj(layr);
        if (!cfsrvl_ready(service, &ret))
                goto err;
        caif_assert(layr->dn != NULL);
        caif_assert(layr->dn->transmit != NULL);

        if (cfpkt_add_head(pkt, &tmp, 1) < 0) {
                pr_err("Packet is erroneous!\n");
                ret = -EPROTO;
                goto err;
        }

        /* Add info-> for MUX-layer to route the packet out. */
        info = cfpkt_info(pkt);
        info->channel_id = service->layer.id;
        info->hdr_len = 1;
        info->dev_info = &service->dev_info;
        return layr->dn->transmit(layr->dn, pkt);
err:
        cfpkt_destroy(pkt);
        return ret;
}