/*
 * This file is part of the UWB stack for linux.
 *
 * Copyright (c) 2020-2021 Qorvo US, Inc.
 *
 * This software is provided under the GNU General Public License, version 2
 * (GPLv2), as well as under a Qorvo commercial license.
 *
 * You may choose to use this software under the terms of the GPLv2 License,
 * version 2 ("GPLv2"), as published by the Free Software Foundation.
 * You should have received a copy of the GPLv2 along with this program.  If
 * not, see <http://www.gnu.org/licenses/>.
 *
 * This program is distributed under the GPLv2 in the hope that it will be
 * useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GPLv2 for more
 * details.
 *
 * If you cannot meet the requirements of the GPLv2, you may not use this
 * software for any purpose without first obtaining a commercial license from
 * Qorvo. Please contact Qorvo to inquire about licensing terms.
 */

#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/string.h>

#include <net/mcps802154_schedule.h>

#include "endless_scheduler.h"
#include "warn_return.h"

struct mcps802154_private_local {
	struct mcps802154_scheduler scheduler;
	struct mcps802154_llhw *llhw;
	struct mcps802154_region *region;
};

static inline struct mcps802154_private_local *
scheduler_to_plocal(const struct mcps802154_scheduler *scheduler)
{
	return container_of(scheduler, struct mcps802154_private_local,
			    scheduler);
}

static struct mcps802154_scheduler *
mcps802154_endless_scheduler_open(struct mcps802154_llhw *llhw)
{
	struct mcps802154_private_local *plocal;

	plocal = kmalloc(sizeof(*plocal), GFP_KERNEL);
	if (!plocal)
		return NULL;
	plocal->llhw = llhw;
	plocal->region = NULL;
	return &plocal->scheduler;
}

static void
mcps802154_endless_scheduler_close(struct mcps802154_scheduler *scheduler)
{
	struct mcps802154_private_local *plocal =
		scheduler_to_plocal(scheduler);

	if (plocal->region)
		mcps802154_region_close(plocal->llhw, plocal->region);

	kfree(plocal);
}

static void
mcps802154_endless_scheduler_notify_stop(struct mcps802154_scheduler *scheduler)
{
	struct mcps802154_private_local *plocal =
		scheduler_to_plocal(scheduler);

	if (plocal->region)
		mcps802154_region_notify_stop(plocal->llhw, plocal->region);
}

static int mcps802154_endless_scheduler_set_region_parameters(
	struct mcps802154_scheduler *scheduler, u32 region_id,
	const char *region_name, const struct nlattr *attrs,
	struct netlink_ext_ack *extack)
{
	struct mcps802154_private_local *plocal =
		scheduler_to_plocal(scheduler);

	if (region_id != 0)
		return -ENOENT;

	/* Close current region. */
	if (plocal->region)
		mcps802154_region_close(plocal->llhw, plocal->region);

	/* Open region, and set its parameters. */
	plocal->region = mcps802154_region_open(plocal->llhw, region_name,
						attrs, extack);

	if (!plocal->region)
		return -EINVAL;

	return 0;
}

static int mcps802154_endless_scheduler_call_region(
	struct mcps802154_scheduler *scheduler, u32 region_id,
	const char *region_name, u32 call_id, const struct nlattr *attrs,
	const struct genl_info *info)
{
	struct mcps802154_private_local *plocal =
		scheduler_to_plocal(scheduler);

	if (!plocal->region)
		return -ENOENT;

	if (region_id != 0 || strcmp(region_name, plocal->region->ops->name))
		return -EINVAL;

	return mcps802154_region_call(plocal->llhw, plocal->region, call_id,
				      attrs, info);
}

static int mcps802154_endless_scheduler_update_schedule(
	struct mcps802154_scheduler *scheduler,
	const struct mcps802154_schedule_update *schedule_update,
	u32 next_timestamp_dtu)
{
	struct mcps802154_private_local *plocal =
		scheduler_to_plocal(scheduler);
	int r;

	if (!plocal->region)
		return -ENOENT;

	r = mcps802154_schedule_set_start(
		schedule_update, schedule_update->expected_start_timestamp_dtu);
	/* Can not fail, only possible error is invalid parameters. */
	WARN_RETURN(r);

	r = mcps802154_schedule_recycle(schedule_update, 0,
					MCPS802154_DURATION_NO_CHANGE);
	/* Can not fail, only possible error is invalid parameters. */
	WARN_RETURN(r);

	r = mcps802154_schedule_add_region(schedule_update, plocal->region, 0,
					   0);

	return r;
}

static struct mcps802154_scheduler_ops mcps802154_endless_scheduler_scheduler = {
	.owner = THIS_MODULE,
	.name = "endless",
	.open = mcps802154_endless_scheduler_open,
	.close = mcps802154_endless_scheduler_close,
	.notify_stop = mcps802154_endless_scheduler_notify_stop,
	.set_region_parameters =
		mcps802154_endless_scheduler_set_region_parameters,
	.call_region = mcps802154_endless_scheduler_call_region,
	.update_schedule = mcps802154_endless_scheduler_update_schedule,
};

int __init mcps802154_endless_scheduler_init(void)
{
	return mcps802154_scheduler_register(
		&mcps802154_endless_scheduler_scheduler);
}

void __exit mcps802154_endless_scheduler_exit(void)
{
	mcps802154_scheduler_unregister(
		&mcps802154_endless_scheduler_scheduler);
}