// 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/errno.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/pkt_sched.h>
#include <net/caif/caif_layer.h>
#include <net/caif/cfsrvl.h>
#include <net/caif/cfpkt.h>
#include <net/caif/caif_dev.h>

#define SRVL_CTRL_PKT_SIZE 1
#define SRVL_FLOW_OFF 0x81
#define SRVL_FLOW_ON  0x80
#define SRVL_SET_PIN  0x82

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

static void cfservl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
			    int phyid)
{
	struct cfsrvl *service = container_obj(layr);

	if (layr->up == NULL || layr->up->ctrlcmd == NULL)
		return;

	switch (ctrl) {
	case CAIF_CTRLCMD_INIT_RSP:
		service->open = true;
		layr->up->ctrlcmd(layr->up, ctrl, phyid);
		break;
	case CAIF_CTRLCMD_DEINIT_RSP:
	case CAIF_CTRLCMD_INIT_FAIL_RSP:
		service->open = false;
		layr->up->ctrlcmd(layr->up, ctrl, phyid);
		break;
	case _CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND:
		if (phyid != service->dev_info.id)
			break;
		if (service->modem_flow_on)
			layr->up->ctrlcmd(layr->up,
					  CAIF_CTRLCMD_FLOW_OFF_IND, phyid);
		service->phy_flow_on = false;
		break;
	case _CAIF_CTRLCMD_PHYIF_FLOW_ON_IND:
		if (phyid != service->dev_info.id)
			return;
		if (service->modem_flow_on) {
			layr->up->ctrlcmd(layr->up,
					   CAIF_CTRLCMD_FLOW_ON_IND,
					   phyid);
		}
		service->phy_flow_on = true;
		break;
	case CAIF_CTRLCMD_FLOW_OFF_IND:
		if (service->phy_flow_on) {
			layr->up->ctrlcmd(layr->up,
					  CAIF_CTRLCMD_FLOW_OFF_IND, phyid);
		}
		service->modem_flow_on = false;
		break;
	case CAIF_CTRLCMD_FLOW_ON_IND:
		if (service->phy_flow_on) {
			layr->up->ctrlcmd(layr->up,
					  CAIF_CTRLCMD_FLOW_ON_IND, phyid);
		}
		service->modem_flow_on = true;
		break;
	case _CAIF_CTRLCMD_PHYIF_DOWN_IND:
		/* In case interface is down, let's fake a remove shutdown */
		layr->up->ctrlcmd(layr->up,
				CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND, phyid);
		break;
	case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:
		layr->up->ctrlcmd(layr->up, ctrl, phyid);
		break;
	default:
		pr_warn("Unexpected ctrl in cfsrvl (%d)\n", ctrl);
		/* We have both modem and phy flow on, send flow on */
		layr->up->ctrlcmd(layr->up, ctrl, phyid);
		service->phy_flow_on = true;
		break;
	}
}

static int cfservl_modemcmd(struct cflayer *layr, enum caif_modemcmd ctrl)
{
	struct cfsrvl *service = container_obj(layr);

	caif_assert(layr != NULL);
	caif_assert(layr->dn != NULL);
	caif_assert(layr->dn->transmit != NULL);

	if (!service->supports_flowctrl)
		return 0;

	switch (ctrl) {
	case CAIF_MODEMCMD_FLOW_ON_REQ:
		{
			struct cfpkt *pkt;
			struct caif_payload_info *info;
			u8 flow_on = SRVL_FLOW_ON;
			pkt = cfpkt_create(SRVL_CTRL_PKT_SIZE);
			if (!pkt)
				return -ENOMEM;

			if (cfpkt_add_head(pkt, &flow_on, 1) < 0) {
				pr_err("Packet is erroneous!\n");
				cfpkt_destroy(pkt);
				return -EPROTO;
			}
			info = cfpkt_info(pkt);
			info->channel_id = service->layer.id;
			info->hdr_len = 1;
			info->dev_info = &service->dev_info;
			cfpkt_set_prio(pkt, TC_PRIO_CONTROL);
			return layr->dn->transmit(layr->dn, pkt);
		}
	case CAIF_MODEMCMD_FLOW_OFF_REQ:
		{
			struct cfpkt *pkt;
			struct caif_payload_info *info;
			u8 flow_off = SRVL_FLOW_OFF;
			pkt = cfpkt_create(SRVL_CTRL_PKT_SIZE);
			if (!pkt)
				return -ENOMEM;

			if (cfpkt_add_head(pkt, &flow_off, 1) < 0) {
				pr_err("Packet is erroneous!\n");
				cfpkt_destroy(pkt);
				return -EPROTO;
			}
			info = cfpkt_info(pkt);
			info->channel_id = service->layer.id;
			info->hdr_len = 1;
			info->dev_info = &service->dev_info;
			cfpkt_set_prio(pkt, TC_PRIO_CONTROL);
			return layr->dn->transmit(layr->dn, pkt);
		}
	default:
	  break;
	}
	return -EINVAL;
}

static void cfsrvl_release(struct cflayer *layer)
{
	struct cfsrvl *service = container_of(layer, struct cfsrvl, layer);
	kfree(service);
}

void cfsrvl_init(struct cfsrvl *service,
		 u8 channel_id,
		 struct dev_info *dev_info,
		 bool supports_flowctrl)
{
	caif_assert(offsetof(struct cfsrvl, layer) == 0);
	service->open = false;
	service->modem_flow_on = true;
	service->phy_flow_on = true;
	service->layer.id = channel_id;
	service->layer.ctrlcmd = cfservl_ctrlcmd;
	service->layer.modemcmd = cfservl_modemcmd;
	service->dev_info = *dev_info;
	service->supports_flowctrl = supports_flowctrl;
	service->release = cfsrvl_release;
}

bool cfsrvl_ready(struct cfsrvl *service, int *err)
{
	if (!service->open) {
		*err = -ENOTCONN;
		return false;
	}
	return true;
}

bool cfsrvl_phyid_match(struct cflayer *layer, int phyid)
{
	struct cfsrvl *servl = container_obj(layer);
	return servl->dev_info.id == phyid;
}

void caif_free_client(struct cflayer *adap_layer)
{
	struct cfsrvl *servl;
	if (adap_layer == NULL || adap_layer->dn == NULL)
		return;
	servl = container_obj(adap_layer->dn);
	servl->release(&servl->layer);
}
EXPORT_SYMBOL(caif_free_client);

void caif_client_register_refcnt(struct cflayer *adapt_layer,
				 void (*hold)(struct cflayer *lyr),
				 void (*put)(struct cflayer *lyr))
{
	struct cfsrvl *service;

	if (WARN_ON(adapt_layer == NULL || adapt_layer->dn == NULL))
		return;
	service = container_of(adapt_layer->dn, struct cfsrvl, layer);
	service->hold = hold;
	service->put = put;
}
EXPORT_SYMBOL(caif_client_register_refcnt);