mac/ca.c - kernel/google-modules/uwb - Git at Google

 /*
  * 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/list.h>
 #include <linux/string.h>

 #include "mcps802154_i.h"
 #include "schedulers.h"
 #include "trace.h"

 struct mcps802154_access_common_ops ca_access_ops = {};

 static int mcps802154_ca_trace_int(struct mcps802154_local *local, const int r)
 {
 	trace_ca_return_int(local, r);
 	return r;
 }

 static void mcps802154_ca_close_scheduler(struct mcps802154_local *local)
 {
 	struct mcps802154_region *region, *r;
 	struct mcps802154_ca *ca = &local->ca;
 	struct list_head *regions = &ca->regions;

 	mcps802154_schedule_clear(local);
 	if (local->ca.scheduler) {
 		mcps802154_scheduler_close(local->ca.scheduler);
 		local->ca.scheduler = NULL;
 	}
 	list_for_each_entry_safe (region, r, regions, ca_entry) {
 		list_del(&region->ca_entry);
 		mcps802154_region_close(&local->llhw, region);
 	}
 	ca->n_regions = 0;
 }

 static int check_and_get_region(struct mcps802154_ca *ca,
 				const char *scheduler_name, u32 region_id,
 				const char *region_name,
 				struct mcps802154_region **sel_region)
 {
 	struct mcps802154_scheduler *scheduler = ca->scheduler;
 	struct list_head *regions = &ca->regions;
 	struct mcps802154_region *region;

 	/* Check scheduler is the correct one. */
 	if (!scheduler || strcmp(scheduler->ops->name, scheduler_name) ||
 	    !region_name)
 		return -EINVAL;

 	list_for_each_entry (region, regions, ca_entry) {
 		if (!strcmp(region_name, region->ops->name) &&
 		    region->id == region_id) {
 			*sel_region = region;
 			return 0;
 		}
 	}
 	return -ENOENT;
 }

 void mcps802154_ca_init(struct mcps802154_local *local)
 {
 	struct mcps802154_ca *ca = &local->ca;

 	local->ca.held = false;
 	local->ca.reset = false;
 	INIT_LIST_HEAD(&ca->regions);
 	ca->n_regions = 0;
 }

 void mcps802154_ca_uninit(struct mcps802154_local *local)
 {
 }

 int mcps802154_ca_start(struct mcps802154_local *local)
 {
 	int r;

 	if (!local->ca.scheduler) {
 		r = mcps802154_ca_set_scheduler(local, "default", NULL, NULL);
 		if (r)
 			return r;

 		r = mcps802154_ca_set_region(local, "default", 0, "default",
 					     NULL, NULL);
 		if (r)
 			return r;
 	}

 	local->start_stop_request = true;
 	mcps802154_fproc_schedule_change(local);

 	return local->started ? 0 : -EIO;
 }

 void mcps802154_ca_stop(struct mcps802154_local *local)
 {
 	local->start_stop_request = false;
 	mcps802154_fproc_schedule_change(local);
 }

 void mcps802154_ca_notify_stop(struct mcps802154_local *local)
 {
 	struct mcps802154_region *region;
 	struct mcps802154_ca *ca = &local->ca;
 	struct list_head *regions = &ca->regions;

 	mcps802154_scheduler_notify_stop(local->ca.scheduler);
 	list_for_each_entry (region, regions, ca_entry) {
 		mcps802154_region_notify_stop(&local->llhw, region);
 	}
 }

 void mcps802154_ca_close(struct mcps802154_local *local)
 {
 	mcps802154_ca_close_scheduler(local);
 }

 int mcps802154_ca_set_scheduler(struct mcps802154_local *local,
 				const char *name,
 				const struct nlattr *params_attr,
 				struct netlink_ext_ack *extack)
 {
 	struct mcps802154_scheduler *scheduler;

 	trace_ca_set_scheduler(local, name);

 	if (local->started)
 		return mcps802154_ca_trace_int(local, -EBUSY);
 	/* Open new scheduler. */
 	scheduler = mcps802154_scheduler_open(local, name, params_attr, extack);
 	if (!scheduler)
 		return mcps802154_ca_trace_int(local, -EINVAL);
 	/* Close previous scheduler and set the new one. */
 	mcps802154_ca_close_scheduler(local);
 	local->ca.scheduler = scheduler;

 	return mcps802154_ca_trace_int(local, 0);
 }

 int mcps802154_ca_set_region(struct mcps802154_local *local,
 			     const char *scheduler_name, u32 region_id,
 			     const char *region_name,
 			     const struct nlattr *params_attr,
 			     struct netlink_ext_ack *extack)
 {
 	struct mcps802154_ca *ca = &local->ca;
 	struct list_head *regions = &ca->regions;
 	struct mcps802154_scheduler *scheduler;
 	struct mcps802154_region *region, *old_region;
 	struct list_head *position = regions;
 	bool region_id_present = false;

 	trace_ca_set_region(local, scheduler_name, region_id, region_name);

 	scheduler = local->ca.scheduler;
 	/* Check scheduler is the correct one. */
 	if (!scheduler || strcmp(scheduler->ops->name, scheduler_name) ||
 	    !region_name)
 		return mcps802154_ca_trace_int(local, -EINVAL);

 	/* Check if we need to replace an already opened region. */
 	list_for_each_entry (old_region, regions, ca_entry) {
 		if (old_region->id == region_id) {
 			region_id_present = true;
 			break;
 		} else if (old_region->id < region_id) {
 			position = &old_region->ca_entry;
 		} else {
 			break;
 		}
 	}

 	/* Regions number is limited by the scheduler */
 	if (!region_id_present && scheduler->n_regions &&
 	    ca->n_regions >= scheduler->n_regions)
 		return mcps802154_ca_trace_int(local, -ENOSPC);

 	region = mcps802154_region_open(&local->llhw, region_name, params_attr,
 					extack);

 	if (!region)
 		return mcps802154_ca_trace_int(local, -EINVAL);
 	region->id = region_id;

 	if (region_id_present) {
 		list_replace(&old_region->ca_entry, &region->ca_entry);
 		mcps802154_region_close(&local->llhw, old_region);
 	} else {
 		list_add(&region->ca_entry, position);
 		ca->n_regions++;
 	}

 	return mcps802154_ca_trace_int(local, 0);
 }

 int mcps802154_ca_scheduler_set_parameters(struct mcps802154_local *local,
 					   const char *name,
 					   const struct nlattr *params_attr,
 					   struct netlink_ext_ack *extack)
 {
 	struct mcps802154_scheduler *scheduler;
 	int r;

 	trace_ca_set_scheduler_parameters(local, name);

 	scheduler = local->ca.scheduler;

 	/* Check scheduler is the correct one. */
 	if (!scheduler || strcmp(scheduler->ops->name, name))
 		return mcps802154_ca_trace_int(local, -EINVAL);

 	r = mcps802154_scheduler_set_parameters(scheduler, params_attr, extack);
 	return mcps802154_ca_trace_int(local, r);
 }

 int mcps802154_ca_scheduler_call(struct mcps802154_local *local,
 				 const char *scheduler_name, u32 call_id,
 				 const struct nlattr *params_attr,
 				 const struct genl_info *info)
 {
 	struct mcps802154_scheduler *scheduler;
 	int r;

 	trace_ca_scheduler_call(local, scheduler_name, call_id);

 	scheduler = local->ca.scheduler;
 	/* Check scheduler is the correct one. */
 	if (!scheduler || strcmp(scheduler->ops->name, scheduler_name))
 		return mcps802154_ca_trace_int(local, -EINVAL);
 	r = mcps802154_scheduler_call(scheduler, call_id, params_attr, info);
 	return mcps802154_ca_trace_int(local, r);
 }

 int mcps802154_ca_set_region_parameters(struct mcps802154_local *local,
 					const char *scheduler_name,
 					u32 region_id, const char *region_name,
 					const struct nlattr *params_attr,
 					struct netlink_ext_ack *extack)
 {
 	struct mcps802154_region *region;
 	int r;

 	trace_ca_set_region_params(local, scheduler_name, region_id,
 				   region_name);

 	r = check_and_get_region(&local->ca, scheduler_name, region_id,
 				 region_name, &region);
 	if (r)
 		goto end;

 	r = mcps802154_region_set_parameters(&local->llhw, region, params_attr,
 					     extack);

 end:
 	return mcps802154_ca_trace_int(local, r);
 }

 int mcps802154_ca_call_region(struct mcps802154_local *local,
 			      const char *scheduler_name, u32 region_id,
 			      const char *region_name, u32 call_id,
 			      const struct nlattr *params_attr,
 			      const struct genl_info *info)
 {
 	struct mcps802154_region *region;
 	int r;

 	trace_ca_call_region(local, scheduler_name, region_id, region_name,
 			     call_id);

 	r = check_and_get_region(&local->ca, scheduler_name, region_id,
 				 region_name, &region);
 	if (r)
 		goto end;

 	r = mcps802154_region_call(&local->llhw, region, call_id, params_attr,
 				   info);

 end:
 	return mcps802154_ca_trace_int(local, r);
 }

 int mcps802154_ca_xmit_skb(struct mcps802154_local *local, struct sk_buff *skb)
 {
 	struct mcps802154_region *region;
 	int r = -EOPNOTSUPP;

 	list_for_each_entry (region, &local->ca.regions, ca_entry) {
 		if (region->ops->xmit_skb) {
 			if (region->ops->xmit_skb(region, skb)) {
 				r = 0;
 				break;
 			}
 		}
 	}
 	return r;
 }

 /**
  * mcps802154_ca_next_region() - Check the current region is still valid, if not
  * change region.
  * @local: MCPS private data.
  * @next_timestamp_dtu: Date of next access opportunity.
  *
  * Return: 0 if unchanged, 1 if changed, or negative error.
  */
 static int mcps802154_ca_next_region(struct mcps802154_local *local,
 				     u32 next_timestamp_dtu)
 {
 	struct mcps802154_schedule *sched = &local->ca.schedule;
 	struct mcps802154_schedule_region *sched_region;
 	int next_dtu = next_timestamp_dtu - sched->start_timestamp_dtu;
 	bool changed = 0;
 	bool once;

 	sched_region = &sched->regions[sched->current_index];
 	once = sched_region->once;

 	/* If the region schedule is over, select the next region if
 	 * possible. */
 	while (once || (sched_region->duration_dtu != 0 &&
 			next_dtu - sched_region->start_dtu >=
 				sched_region->duration_dtu)) {
 		sched->current_index++;
 		changed = 1;
 		once = false;

 		/* No more region, need a new schedule. */
 		if (sched->current_index >= sched->n_regions) {
 			/* Reduce the schedule duration when not fully used. */
 			if (sched_region->once && sched_region->duration_dtu) {
 				sched->duration_dtu =
 					next_timestamp_dtu -
 					sched->start_timestamp_dtu;
 			}
 			return mcps802154_schedule_update(local,
 							  next_timestamp_dtu);
 		}

 		sched_region = &sched->regions[sched->current_index];
 	}

 	return changed;
 }

 /**
  * mcps802154_ca_nothing() - Fill and return a nothing access.
  * @local: MCPS private data.
  * @timestamp_dtu: Start of nothing period.
  * @duration_dtu: Duration of nothing period, or 0 for endless.
  *
  * Return: Pointer to access allocated inside the context.
  */
 struct mcps802154_access *mcps802154_ca_nothing(struct mcps802154_local *local,
 						u32 timestamp_dtu,
 						int duration_dtu)
 {
 	struct mcps802154_access *access = &local->ca.idle_access;

 	access->method = MCPS802154_ACCESS_METHOD_NOTHING;
 	access->common_ops = &ca_access_ops;
 	access->timestamp_dtu = timestamp_dtu;
 	access->duration_dtu = duration_dtu;
 	return access;
 }

 struct mcps802154_access *
 mcps802154_ca_get_access(struct mcps802154_local *local, u32 next_timestamp_dtu)
 {
 	struct mcps802154_schedule *sched = &local->ca.schedule;
 	struct mcps802154_schedule_region *sched_region;
 	struct mcps802154_region *region;
 	struct mcps802154_access *access;
 	u32 idle_timestamp_dtu, region_start_timestamp_dtu;
 	int next_in_region_dtu, region_duration_dtu;
 	int r, changed;

 	local->ca.held = false;

 	trace_ca_get_access(local, next_timestamp_dtu);

 	if (local->ca.reset) {
 		mcps802154_schedule_clear(local);
 		local->ca.reset = false;
 	}

 	/* Do not examine accesses later than this date. */
 	idle_timestamp_dtu = next_timestamp_dtu + local->llhw.idle_dtu;
 	while (1) {
 		/* Need a schedule. */
 		if (!sched->n_regions)
 			r = mcps802154_schedule_update(local,
 						       next_timestamp_dtu);
 		else
 			/* Need a region. */
 			r = mcps802154_ca_next_region(local,
 						      next_timestamp_dtu);

 		/* Stay in IDLE when no schedule. */
 		if (r == -ENOENT)
 			return mcps802154_ca_nothing(local, next_timestamp_dtu,
 						     0);
 		else if (r < 0)
 			return NULL;

 		changed = r;
 		sched_region = &sched->regions[sched->current_index];
 		region = sched_region->region;
 		region_start_timestamp_dtu =
 			sched->start_timestamp_dtu + sched_region->start_dtu;
 		region_duration_dtu = sched_region->duration_dtu;

 		if (changed) {
 			if (is_before_dtu(next_timestamp_dtu,
 					  region_start_timestamp_dtu)) {
 				/* Access date may be postponed. */
 				next_timestamp_dtu = region_start_timestamp_dtu;
 			}
 		}

 		/* Get access. */
 		if (region_duration_dtu)
 			next_in_region_dtu =
 				next_timestamp_dtu - region_start_timestamp_dtu;
 		else
 			next_in_region_dtu = 0;
 		trace_region_get_access(local, region, next_timestamp_dtu,
 					next_in_region_dtu,
 					region_duration_dtu);
 		access = region->ops->get_access(region, next_timestamp_dtu,
 						 next_in_region_dtu,
 						 region_duration_dtu);

 		if (access)
 			return access;

 		/* If no access is found, look for next region, or wait. */
 		if (region_duration_dtu) {
 			u32 region_end_timestamp_dtu =
 				region_start_timestamp_dtu +
 				region_duration_dtu;

 			if (is_before_dtu(idle_timestamp_dtu,
 					  region_end_timestamp_dtu)) {
 				return mcps802154_ca_nothing(
 					local, next_timestamp_dtu,
 					region_end_timestamp_dtu -
 						next_timestamp_dtu);
 			}

 			/* Continue after the current region. */
 			next_timestamp_dtu = region_end_timestamp_dtu;
 		} else {
 			return mcps802154_ca_nothing(local, next_timestamp_dtu,
 						     0);
 		}
 	}
 }

 void mcps802154_ca_may_reschedule(struct mcps802154_local *local)
 {
 	if (!local->ca.held)
 		mcps802154_fproc_schedule_change(local);
 }

 void mcps802154_ca_access_hold(struct mcps802154_local *local)
 {
 	local->ca.held = true;
 }

 void mcps802154_ca_invalidate_schedule(struct mcps802154_local *local)
 {
 	local->ca.reset = true;

 	mcps802154_fproc_schedule_change(local);
 }
	/*
	* 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/list.h>
	#include <linux/string.h>

	#include "mcps802154_i.h"
	#include "schedulers.h"
	#include "trace.h"

	struct mcps802154_access_common_ops ca_access_ops = {};

	static int mcps802154_ca_trace_int(struct mcps802154_local *local, const int r)
	{
	trace_ca_return_int(local, r);
	return r;
	}

	static void mcps802154_ca_close_scheduler(struct mcps802154_local *local)
	{
	struct mcps802154_region region, r;
	struct mcps802154_ca *ca = &local->ca;
	struct list_head *regions = &ca->regions;

	mcps802154_schedule_clear(local);
	if (local->ca.scheduler) {
	mcps802154_scheduler_close(local->ca.scheduler);
	local->ca.scheduler = NULL;
	}
	list_for_each_entry_safe (region, r, regions, ca_entry) {
	list_del(&region->ca_entry);
	mcps802154_region_close(&local->llhw, region);
	}
	ca->n_regions = 0;
	}

	static int check_and_get_region(struct mcps802154_ca *ca,
	const char *scheduler_name, u32 region_id,
	const char *region_name,
	struct mcps802154_region **sel_region)
	{
	struct mcps802154_scheduler *scheduler = ca->scheduler;
	struct list_head *regions = &ca->regions;
	struct mcps802154_region *region;

	/* Check scheduler is the correct one. */
	if (!scheduler \|\| strcmp(scheduler->ops->name, scheduler_name) \|\|
	!region_name)
	return -EINVAL;

	list_for_each_entry (region, regions, ca_entry) {
	if (!strcmp(region_name, region->ops->name) &&
	region->id == region_id) {
	*sel_region = region;
	return 0;
	}
	}
	return -ENOENT;
	}

	void mcps802154_ca_init(struct mcps802154_local *local)
	{
	struct mcps802154_ca *ca = &local->ca;

	local->ca.held = false;
	local->ca.reset = false;
	INIT_LIST_HEAD(&ca->regions);
	ca->n_regions = 0;
	}

	void mcps802154_ca_uninit(struct mcps802154_local *local)
	{
	}

	int mcps802154_ca_start(struct mcps802154_local *local)
	{
	int r;

	if (!local->ca.scheduler) {
	r = mcps802154_ca_set_scheduler(local, "default", NULL, NULL);
	if (r)
	return r;

	r = mcps802154_ca_set_region(local, "default", 0, "default",
	NULL, NULL);
	if (r)
	return r;
	}

	local->start_stop_request = true;
	mcps802154_fproc_schedule_change(local);

	return local->started ? 0 : -EIO;
	}

	void mcps802154_ca_stop(struct mcps802154_local *local)
	{
	local->start_stop_request = false;
	mcps802154_fproc_schedule_change(local);
	}

	void mcps802154_ca_notify_stop(struct mcps802154_local *local)
	{
	struct mcps802154_region *region;
	struct mcps802154_ca *ca = &local->ca;
	struct list_head *regions = &ca->regions;

	mcps802154_scheduler_notify_stop(local->ca.scheduler);
	list_for_each_entry (region, regions, ca_entry) {
	mcps802154_region_notify_stop(&local->llhw, region);
	}
	}

	void mcps802154_ca_close(struct mcps802154_local *local)
	{
	mcps802154_ca_close_scheduler(local);
	}

	int mcps802154_ca_set_scheduler(struct mcps802154_local *local,
	const char *name,
	const struct nlattr *params_attr,
	struct netlink_ext_ack *extack)
	{
	struct mcps802154_scheduler *scheduler;

	trace_ca_set_scheduler(local, name);

	if (local->started)
	return mcps802154_ca_trace_int(local, -EBUSY);
	/* Open new scheduler. */
	scheduler = mcps802154_scheduler_open(local, name, params_attr, extack);
	if (!scheduler)
	return mcps802154_ca_trace_int(local, -EINVAL);
	/* Close previous scheduler and set the new one. */
	mcps802154_ca_close_scheduler(local);
	local->ca.scheduler = scheduler;

	return mcps802154_ca_trace_int(local, 0);
	}

	int mcps802154_ca_set_region(struct mcps802154_local *local,
	const char *scheduler_name, u32 region_id,
	const char *region_name,
	const struct nlattr *params_attr,
	struct netlink_ext_ack *extack)
	{
	struct mcps802154_ca *ca = &local->ca;
	struct list_head *regions = &ca->regions;
	struct mcps802154_scheduler *scheduler;
	struct mcps802154_region region, old_region;
	struct list_head *position = regions;
	bool region_id_present = false;

	trace_ca_set_region(local, scheduler_name, region_id, region_name);

	scheduler = local->ca.scheduler;
	/* Check scheduler is the correct one. */
	if (!scheduler \|\| strcmp(scheduler->ops->name, scheduler_name) \|\|
	!region_name)
	return mcps802154_ca_trace_int(local, -EINVAL);

	/* Check if we need to replace an already opened region. */
	list_for_each_entry (old_region, regions, ca_entry) {
	if (old_region->id == region_id) {
	region_id_present = true;
	break;
	} else if (old_region->id < region_id) {
	position = &old_region->ca_entry;
	} else {
	break;
	}
	}

	/* Regions number is limited by the scheduler */
	if (!region_id_present && scheduler->n_regions &&
	ca->n_regions >= scheduler->n_regions)
	return mcps802154_ca_trace_int(local, -ENOSPC);

	region = mcps802154_region_open(&local->llhw, region_name, params_attr,
	extack);

	if (!region)
	return mcps802154_ca_trace_int(local, -EINVAL);
	region->id = region_id;

	if (region_id_present) {
	list_replace(&old_region->ca_entry, &region->ca_entry);
	mcps802154_region_close(&local->llhw, old_region);
	} else {
	list_add(&region->ca_entry, position);
	ca->n_regions++;
	}

	return mcps802154_ca_trace_int(local, 0);
	}

	int mcps802154_ca_scheduler_set_parameters(struct mcps802154_local *local,
	const char *name,
	const struct nlattr *params_attr,
	struct netlink_ext_ack *extack)
	{
	struct mcps802154_scheduler *scheduler;
	int r;

	trace_ca_set_scheduler_parameters(local, name);

	scheduler = local->ca.scheduler;

	/* Check scheduler is the correct one. */
	if (!scheduler \|\| strcmp(scheduler->ops->name, name))
	return mcps802154_ca_trace_int(local, -EINVAL);

	r = mcps802154_scheduler_set_parameters(scheduler, params_attr, extack);
	return mcps802154_ca_trace_int(local, r);
	}

	int mcps802154_ca_scheduler_call(struct mcps802154_local *local,
	const char *scheduler_name, u32 call_id,
	const struct nlattr *params_attr,
	const struct genl_info *info)
	{
	struct mcps802154_scheduler *scheduler;
	int r;

	trace_ca_scheduler_call(local, scheduler_name, call_id);

	scheduler = local->ca.scheduler;
	/* Check scheduler is the correct one. */
	if (!scheduler \|\| strcmp(scheduler->ops->name, scheduler_name))
	return mcps802154_ca_trace_int(local, -EINVAL);
	r = mcps802154_scheduler_call(scheduler, call_id, params_attr, info);
	return mcps802154_ca_trace_int(local, r);
	}

	int mcps802154_ca_set_region_parameters(struct mcps802154_local *local,
	const char *scheduler_name,
	u32 region_id, const char *region_name,
	const struct nlattr *params_attr,
	struct netlink_ext_ack *extack)
	{
	struct mcps802154_region *region;
	int r;

	trace_ca_set_region_params(local, scheduler_name, region_id,
	region_name);

	r = check_and_get_region(&local->ca, scheduler_name, region_id,
	region_name, &region);
	if (r)
	goto end;

	r = mcps802154_region_set_parameters(&local->llhw, region, params_attr,
	extack);

	end:
	return mcps802154_ca_trace_int(local, r);
	}

	int mcps802154_ca_call_region(struct mcps802154_local *local,
	const char *scheduler_name, u32 region_id,
	const char *region_name, u32 call_id,
	const struct nlattr *params_attr,
	const struct genl_info *info)
	{
	struct mcps802154_region *region;
	int r;

	trace_ca_call_region(local, scheduler_name, region_id, region_name,
	call_id);

	r = check_and_get_region(&local->ca, scheduler_name, region_id,
	region_name, &region);
	if (r)
	goto end;

	r = mcps802154_region_call(&local->llhw, region, call_id, params_attr,
	info);

	end:
	return mcps802154_ca_trace_int(local, r);
	}

	int mcps802154_ca_xmit_skb(struct mcps802154_local local, struct sk_buff skb)
	{
	struct mcps802154_region *region;
	int r = -EOPNOTSUPP;

	list_for_each_entry (region, &local->ca.regions, ca_entry) {
	if (region->ops->xmit_skb) {
	if (region->ops->xmit_skb(region, skb)) {
	r = 0;
	break;
	}
	}
	}
	return r;
	}

	/**
	* mcps802154_ca_next_region() - Check the current region is still valid, if not
	* change region.
	* @local: MCPS private data.
	* @next_timestamp_dtu: Date of next access opportunity.
	*
	* Return: 0 if unchanged, 1 if changed, or negative error.
	*/
	static int mcps802154_ca_next_region(struct mcps802154_local *local,
	u32 next_timestamp_dtu)
	{
	struct mcps802154_schedule *sched = &local->ca.schedule;
	struct mcps802154_schedule_region *sched_region;
	int next_dtu = next_timestamp_dtu - sched->start_timestamp_dtu;
	bool changed = 0;
	bool once;

	sched_region = &sched->regions[sched->current_index];
	once = sched_region->once;

	/* If the region schedule is over, select the next region if
	* possible. */
	while (once \|\| (sched_region->duration_dtu != 0 &&
	next_dtu - sched_region->start_dtu >=
	sched_region->duration_dtu)) {
	sched->current_index++;
	changed = 1;
	once = false;

	/* No more region, need a new schedule. */
	if (sched->current_index >= sched->n_regions) {
	/* Reduce the schedule duration when not fully used. */
	if (sched_region->once && sched_region->duration_dtu) {
	sched->duration_dtu =
	next_timestamp_dtu -
	sched->start_timestamp_dtu;
	}
	return mcps802154_schedule_update(local,
	next_timestamp_dtu);
	}

	sched_region = &sched->regions[sched->current_index];
	}

	return changed;
	}

	/**
	* mcps802154_ca_nothing() - Fill and return a nothing access.
	* @local: MCPS private data.
	* @timestamp_dtu: Start of nothing period.
	* @duration_dtu: Duration of nothing period, or 0 for endless.
	*
	* Return: Pointer to access allocated inside the context.
	*/
	struct mcps802154_access mcps802154_ca_nothing(struct mcps802154_local local,
	u32 timestamp_dtu,
	int duration_dtu)
	{
	struct mcps802154_access *access = &local->ca.idle_access;

	access->method = MCPS802154_ACCESS_METHOD_NOTHING;
	access->common_ops = &ca_access_ops;
	access->timestamp_dtu = timestamp_dtu;
	access->duration_dtu = duration_dtu;
	return access;
	}

	struct mcps802154_access *
	mcps802154_ca_get_access(struct mcps802154_local *local, u32 next_timestamp_dtu)
	{
	struct mcps802154_schedule *sched = &local->ca.schedule;
	struct mcps802154_schedule_region *sched_region;
	struct mcps802154_region *region;
	struct mcps802154_access *access;
	u32 idle_timestamp_dtu, region_start_timestamp_dtu;
	int next_in_region_dtu, region_duration_dtu;
	int r, changed;

	local->ca.held = false;

	trace_ca_get_access(local, next_timestamp_dtu);

	if (local->ca.reset) {
	mcps802154_schedule_clear(local);
	local->ca.reset = false;
	}

	/* Do not examine accesses later than this date. */
	idle_timestamp_dtu = next_timestamp_dtu + local->llhw.idle_dtu;
	while (1) {
	/* Need a schedule. */
	if (!sched->n_regions)
	r = mcps802154_schedule_update(local,
	next_timestamp_dtu);
	else
	/* Need a region. */
	r = mcps802154_ca_next_region(local,
	next_timestamp_dtu);

	/* Stay in IDLE when no schedule. */
	if (r == -ENOENT)
	return mcps802154_ca_nothing(local, next_timestamp_dtu,
	0);
	else if (r < 0)
	return NULL;

	changed = r;
	sched_region = &sched->regions[sched->current_index];
	region = sched_region->region;
	region_start_timestamp_dtu =
	sched->start_timestamp_dtu + sched_region->start_dtu;
	region_duration_dtu = sched_region->duration_dtu;

	if (changed) {
	if (is_before_dtu(next_timestamp_dtu,
	region_start_timestamp_dtu)) {
	/* Access date may be postponed. */
	next_timestamp_dtu = region_start_timestamp_dtu;
	}
	}

	/* Get access. */
	if (region_duration_dtu)
	next_in_region_dtu =
	next_timestamp_dtu - region_start_timestamp_dtu;
	else
	next_in_region_dtu = 0;
	trace_region_get_access(local, region, next_timestamp_dtu,
	next_in_region_dtu,
	region_duration_dtu);
	access = region->ops->get_access(region, next_timestamp_dtu,
	next_in_region_dtu,
	region_duration_dtu);

	if (access)
	return access;

	/* If no access is found, look for next region, or wait. */
	if (region_duration_dtu) {
	u32 region_end_timestamp_dtu =
	region_start_timestamp_dtu +
	region_duration_dtu;

	if (is_before_dtu(idle_timestamp_dtu,
	region_end_timestamp_dtu)) {
	return mcps802154_ca_nothing(
	local, next_timestamp_dtu,
	region_end_timestamp_dtu -
	next_timestamp_dtu);
	}

	/* Continue after the current region. */
	next_timestamp_dtu = region_end_timestamp_dtu;
	} else {
	return mcps802154_ca_nothing(local, next_timestamp_dtu,
	0);
	}
	}
	}

	void mcps802154_ca_may_reschedule(struct mcps802154_local *local)
	{
	if (!local->ca.held)
	mcps802154_fproc_schedule_change(local);
	}

	void mcps802154_ca_access_hold(struct mcps802154_local *local)
	{
	local->ca.held = true;
	}

	void mcps802154_ca_invalidate_schedule(struct mcps802154_local *local)
	{
	local->ca.reset = true;

	mcps802154_fproc_schedule_change(local);
	}