// 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/kernel.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <net/caif/caif_layer.h>
#include <net/caif/cfsrvl.h>
#include <net/caif/cfpkt.h>

#define container_obj(layr) ((struct cfsrvl *) layr)
#define UTIL_PAYLOAD  0x00
#define UTIL_CMD_BIT  0x80
#define UTIL_REMOTE_SHUTDOWN 0x82
#define UTIL_FLOW_OFF 0x81
#define UTIL_FLOW_ON  0x80

static int cfutill_receive(struct cflayer *layr, struct cfpkt *pkt);
static int cfutill_transmit(struct cflayer *layr, struct cfpkt *pkt);

struct cflayer *cfutill_create(u8 channel_id, struct dev_info *dev_info)
{
	struct cfsrvl *util = kzalloc(sizeof(struct cfsrvl), GFP_ATOMIC);
	if (!util)
		return NULL;
	caif_assert(offsetof(struct cfsrvl, layer) == 0);
	cfsrvl_init(util, channel_id, dev_info, true);
	util->layer.receive = cfutill_receive;
	util->layer.transmit = cfutill_transmit;
	snprintf(util->layer.name, CAIF_LAYER_NAME_SZ, "util1");
	return &util->layer;
}

static int cfutill_receive(struct cflayer *layr, struct cfpkt *pkt)
{
	u8 cmd = -1;
	struct cfsrvl *service = container_obj(layr);
	caif_assert(layr != NULL);
	caif_assert(layr->up != NULL);
	caif_assert(layr->up->receive != NULL);
	caif_assert(layr->up->ctrlcmd != NULL);
	if (cfpkt_extr_head(pkt, &cmd, 1) < 0) {
		pr_err("Packet is erroneous!\n");
		cfpkt_destroy(pkt);
		return -EPROTO;
	}

	switch (cmd) {
	case UTIL_PAYLOAD:
		return layr->up->receive(layr->up, pkt);
	case UTIL_FLOW_OFF:
		layr->ctrlcmd(layr, CAIF_CTRLCMD_FLOW_OFF_IND, 0);
		cfpkt_destroy(pkt);
		return 0;
	case UTIL_FLOW_ON:
		layr->ctrlcmd(layr, CAIF_CTRLCMD_FLOW_ON_IND, 0);
		cfpkt_destroy(pkt);
		return 0;
	case UTIL_REMOTE_SHUTDOWN:	/* Remote Shutdown Request */
		pr_err("REMOTE SHUTDOWN REQUEST RECEIVED\n");
		layr->ctrlcmd(layr, CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND, 0);
		service->open = false;
		cfpkt_destroy(pkt);
		return 0;
	default:
		cfpkt_destroy(pkt);
		pr_warn("Unknown service control %d (0x%x)\n", cmd, cmd);
		return -EPROTO;
	}
}

static int cfutill_transmit(struct cflayer *layr, struct cfpkt *pkt)
{
	u8 zero = 0;
	struct caif_payload_info *info;
	int ret;
	struct cfsrvl *service = container_obj(layr);
	caif_assert(layr != NULL);
	caif_assert(layr->dn != NULL);
	caif_assert(layr->dn->transmit != NULL);

	if (!cfsrvl_ready(service, &ret)) {
		cfpkt_destroy(pkt);
		return ret;
	}

	cfpkt_add_head(pkt, &zero, 1);
	/* Add info for MUX-layer to route the packet out. */
	info = cfpkt_info(pkt);
	info->channel_id = service->layer.id;
	/*
	 * To optimize alignment, we add up the size of CAIF header before
	 * payload.
	 */
	info->hdr_len = 1;
	info->dev_info = &service->dev_info;
	return layr->dn->transmit(layr->dn, pkt);
}