switch.c

/*
 * Handling of a single switch chip, part of a switch fabric
 *
 * Copyright (c) 2017 Savoir-faire Linux Inc.
 *	Vivien Didelot <vivien.didelot@savoirfairelinux.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

#include <linux/netdevice.h>
#include <linux/notifier.h>
#include <net/switchdev.h>

#include "dsa_priv.h"

static unsigned int dsa_switch_fastest_ageing_time(struct dsa_switch *ds,
						   unsigned int ageing_time)
{
	int i;

	for (i = 0; i < ds->num_ports; ++i) {
		struct dsa_port *dp = &ds->ports[i];

		if (dp->ageing_time && dp->ageing_time < ageing_time)
			ageing_time = dp->ageing_time;
	}

	return ageing_time;
}

static int dsa_switch_ageing_time(struct dsa_switch *ds,
				  struct dsa_notifier_ageing_time_info *info)
{
	unsigned int ageing_time = info->ageing_time;
	struct switchdev_trans *trans = info->trans;

	/* Do not care yet about other switch chips of the fabric */
	if (ds->index != info->sw_index)
		return 0;

	if (switchdev_trans_ph_prepare(trans)) {
		if (ds->ageing_time_min && ageing_time < ds->ageing_time_min)
			return -ERANGE;
		if (ds->ageing_time_max && ageing_time > ds->ageing_time_max)
			return -ERANGE;
		return 0;
	}

	/* Program the fastest ageing time in case of multiple bridges */
	ageing_time = dsa_switch_fastest_ageing_time(ds, ageing_time);

	if (ds->ops->set_ageing_time)
		return ds->ops->set_ageing_time(ds, ageing_time);

	return 0;
}

static int dsa_switch_bridge_join(struct dsa_switch *ds,
				  struct dsa_notifier_bridge_info *info)
{
	if (ds->index == info->sw_index && ds->ops->port_bridge_join)
		return ds->ops->port_bridge_join(ds, info->port, info->br);

	if (ds->index != info->sw_index && ds->ops->crosschip_bridge_join)
		return ds->ops->crosschip_bridge_join(ds, info->sw_index,
						      info->port, info->br);

	return 0;
}

static int dsa_switch_bridge_leave(struct dsa_switch *ds,
				   struct dsa_notifier_bridge_info *info)
{
	if (ds->index == info->sw_index && ds->ops->port_bridge_leave)
		ds->ops->port_bridge_leave(ds, info->port, info->br);

	if (ds->index != info->sw_index && ds->ops->crosschip_bridge_leave)
		ds->ops->crosschip_bridge_leave(ds, info->sw_index, info->port,
						info->br);

	return 0;
}

static int dsa_switch_event(struct notifier_block *nb,
			    unsigned long event, void *info)
{
	struct dsa_switch *ds = container_of(nb, struct dsa_switch, nb);
	int err;

	switch (event) {
	case DSA_NOTIFIER_AGEING_TIME:
		err = dsa_switch_ageing_time(ds, info);
		break;
	case DSA_NOTIFIER_BRIDGE_JOIN:
		err = dsa_switch_bridge_join(ds, info);
		break;
	case DSA_NOTIFIER_BRIDGE_LEAVE:
		err = dsa_switch_bridge_leave(ds, info);
		break;
	default:
		err = -EOPNOTSUPP;
		break;
	}

	/* Non-switchdev operations cannot be rolled back. If a DSA driver
	 * returns an error during the chained call, switch chips may be in an
	 * inconsistent state.
	 */
	if (err)
		dev_dbg(ds->dev, "breaking chain for DSA event %lu (%d)\n",
			event, err);

	return notifier_from_errno(err);
}

int dsa_switch_register_notifier(struct dsa_switch *ds)
{
	ds->nb.notifier_call = dsa_switch_event;

	return raw_notifier_chain_register(&ds->dst->nh, &ds->nb);
}

void dsa_switch_unregister_notifier(struct dsa_switch *ds)
{
	int err;

	err = raw_notifier_chain_unregister(&ds->dst->nh, &ds->nb);
	if (err)
		dev_err(ds->dev, "failed to unregister notifier (%d)\n", err);
}