/*
 * net/dsa/dsa.c - Hardware switch handling
 * Copyright (c) 2008-2009 Marvell Semiconductor
 *
 * 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/list.h>
#include <linux/netdevice.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <net/dsa.h>
#include "dsa_priv.h"

char dsa_driver_version[] = "0.1";


/* switch driver registration ***********************************************/
static DEFINE_MUTEX(dsa_switch_drivers_mutex);
static LIST_HEAD(dsa_switch_drivers);

void register_switch_driver(struct dsa_switch_driver *drv)
{
	mutex_lock(&dsa_switch_drivers_mutex);
	list_add_tail(&drv->list, &dsa_switch_drivers);
	mutex_unlock(&dsa_switch_drivers_mutex);
}

void unregister_switch_driver(struct dsa_switch_driver *drv)
{
	mutex_lock(&dsa_switch_drivers_mutex);
	list_del_init(&drv->list);
	mutex_unlock(&dsa_switch_drivers_mutex);
}

static struct dsa_switch_driver *
dsa_switch_probe(struct mii_bus *bus, int sw_addr, char **_name)
{
	struct dsa_switch_driver *ret;
	struct list_head *list;
	char *name;

	ret = NULL;
	name = NULL;

	mutex_lock(&dsa_switch_drivers_mutex);
	list_for_each(list, &dsa_switch_drivers) {
		struct dsa_switch_driver *drv;

		drv = list_entry(list, struct dsa_switch_driver, list);

		name = drv->probe(bus, sw_addr);
		if (name != NULL) {
			ret = drv;
			break;
		}
	}
	mutex_unlock(&dsa_switch_drivers_mutex);

	*_name = name;

	return ret;
}


/* basic switch operations **************************************************/
static struct dsa_switch *
dsa_switch_setup(struct dsa_switch_tree *dst, int index,
		 struct device *parent, struct mii_bus *bus)
{
	struct dsa_chip_data *pd = dst->pd->chip + index;
	struct dsa_switch_driver *drv;
	struct dsa_switch *ds;
	int ret;
	char *name;
	int i;

	/*
	 * Probe for switch model.
	 */
	drv = dsa_switch_probe(bus, pd->sw_addr, &name);
	if (drv == NULL) {
		printk(KERN_ERR "%s[%d]: could not detect attached switch\n",
		       dst->master_netdev->name, index);
		return ERR_PTR(-EINVAL);
	}
	printk(KERN_INFO "%s[%d]: detected a %s switch\n",
		dst->master_netdev->name, index, name);


	/*
	 * Allocate and initialise switch state.
	 */
	ds = kzalloc(sizeof(*ds) + drv->priv_size, GFP_KERNEL);
	if (ds == NULL)
		return ERR_PTR(-ENOMEM);

	ds->dst = dst;
	ds->index = index;
	ds->pd = dst->pd->chip + index;
	ds->drv = drv;
	ds->master_mii_bus = bus;


	/*
	 * Validate supplied switch configuration.
	 */
	for (i = 0; i < DSA_MAX_PORTS; i++) {
		char *name;

		name = pd->port_names[i];
		if (name == NULL)
			continue;

		if (!strcmp(name, "cpu")) {
			if (dst->cpu_switch != -1) {
				printk(KERN_ERR "multiple cpu ports?!\n");
				ret = -EINVAL;
				goto out;
			}
			dst->cpu_switch = index;
			dst->cpu_port = i;
		} else if (!strcmp(name, "dsa")) {
			ds->dsa_port_mask |= 1 << i;
		} else {
			ds->phys_port_mask |= 1 << i;
		}
	}


	/*
	 * If the CPU connects to this switch, set the switch tree
	 * tagging protocol to the preferred tagging format of this
	 * switch.
	 */
	if (ds->dst->cpu_switch == index)
		ds->dst->tag_protocol = drv->tag_protocol;


	/*
	 * Do basic register setup.
	 */
	ret = drv->setup(ds);
	if (ret < 0)
		goto out;

	ret = drv->set_addr(ds, dst->master_netdev->dev_addr);
	if (ret < 0)
		goto out;

	ds->slave_mii_bus = mdiobus_alloc();
	if (ds->slave_mii_bus == NULL) {
		ret = -ENOMEM;
		goto out;
	}
	dsa_slave_mii_bus_init(ds);

	ret = mdiobus_register(ds->slave_mii_bus);
	if (ret < 0)
		goto out_free;


	/*
	 * Create network devices for physical switch ports.
	 */
	for (i = 0; i < DSA_MAX_PORTS; i++) {
		struct net_device *slave_dev;

		if (!(ds->phys_port_mask & (1 << i)))
			continue;

		slave_dev = dsa_slave_create(ds, parent, i, pd->port_names[i]);
		if (slave_dev == NULL) {
			printk(KERN_ERR "%s[%d]: can't create dsa "
			       "slave device for port %d(%s)\n",
			       dst->master_netdev->name,
			       index, i, pd->port_names[i]);
			continue;
		}

		ds->ports[i] = slave_dev;
	}

	return ds;

out_free:
	mdiobus_free(ds->slave_mii_bus);
out:
	kfree(ds);
	return ERR_PTR(ret);
}

static void dsa_switch_destroy(struct dsa_switch *ds)
{
}


/* hooks for ethertype-less tagging formats *********************************/
/*
 * The original DSA tag format and some other tag formats have no
 * ethertype, which means that we need to add a little hack to the
 * networking receive path to make sure that received frames get
 * the right ->protocol assigned to them when one of those tag
 * formats is in use.
 */
bool dsa_uses_dsa_tags(void *dsa_ptr)
{
	struct dsa_switch_tree *dst = dsa_ptr;

	return !!(dst->tag_protocol == htons(ETH_P_DSA));
}

bool dsa_uses_trailer_tags(void *dsa_ptr)
{
	struct dsa_switch_tree *dst = dsa_ptr;

	return !!(dst->tag_protocol == htons(ETH_P_TRAILER));
}


/* link polling *************************************************************/
static void dsa_link_poll_work(struct work_struct *ugly)
{
	struct dsa_switch_tree *dst;
	int i;

	dst = container_of(ugly, struct dsa_switch_tree, link_poll_work);

	for (i = 0; i < dst->pd->nr_chips; i++) {
		struct dsa_switch *ds = dst->ds[i];

		if (ds != NULL && ds->drv->poll_link != NULL)
			ds->drv->poll_link(ds);
	}

	mod_timer(&dst->link_poll_timer, round_jiffies(jiffies + HZ));
}

static void dsa_link_poll_timer(unsigned long _dst)
{
	struct dsa_switch_tree *dst = (void *)_dst;

	schedule_work(&dst->link_poll_work);
}


/* platform driver init and cleanup *****************************************/
static int dev_is_class(struct device *dev, void *class)
{
	if (dev->class != NULL && !strcmp(dev->class->name, class))
		return 1;

	return 0;
}

static struct device *dev_find_class(struct device *parent, char *class)
{
	if (dev_is_class(parent, class)) {
		get_device(parent);
		return parent;
	}

	return device_find_child(parent, class, dev_is_class);
}

static struct mii_bus *dev_to_mii_bus(struct device *dev)
{
	struct device *d;

	d = dev_find_class(dev, "mdio_bus");
	if (d != NULL) {
		struct mii_bus *bus;

		bus = to_mii_bus(d);
		put_device(d);

		return bus;
	}

	return NULL;
}

static struct net_device *dev_to_net_device(struct device *dev)
{
	struct device *d;

	d = dev_find_class(dev, "net");
	if (d != NULL) {
		struct net_device *nd;

		nd = to_net_dev(d);
		dev_hold(nd);
		put_device(d);

		return nd;
	}

	return NULL;
}

static int dsa_probe(struct platform_device *pdev)
{
	static int dsa_version_printed;
	struct dsa_platform_data *pd = pdev->dev.platform_data;
	struct net_device *dev;
	struct dsa_switch_tree *dst;
	int i;

	if (!dsa_version_printed++)
		printk(KERN_NOTICE "Distributed Switch Architecture "
			"driver version %s\n", dsa_driver_version);

	if (pd == NULL || pd->netdev == NULL)
		return -EINVAL;

	dev = dev_to_net_device(pd->netdev);
	if (dev == NULL)
		return -EINVAL;

	if (dev->dsa_ptr != NULL) {
		dev_put(dev);
		return -EEXIST;
	}

	dst = kzalloc(sizeof(*dst), GFP_KERNEL);
	if (dst == NULL) {
		dev_put(dev);
		return -ENOMEM;
	}

	platform_set_drvdata(pdev, dst);

	dst->pd = pd;
	dst->master_netdev = dev;
	dst->cpu_switch = -1;
	dst->cpu_port = -1;

	for (i = 0; i < pd->nr_chips; i++) {
		struct mii_bus *bus;
		struct dsa_switch *ds;

		bus = dev_to_mii_bus(pd->chip[i].mii_bus);
		if (bus == NULL) {
			printk(KERN_ERR "%s[%d]: no mii bus found for "
				"dsa switch\n", dev->name, i);
			continue;
		}

		ds = dsa_switch_setup(dst, i, &pdev->dev, bus);
		if (IS_ERR(ds)) {
			printk(KERN_ERR "%s[%d]: couldn't create dsa switch "
				"instance (error %ld)\n", dev->name, i,
				PTR_ERR(ds));
			continue;
		}

		dst->ds[i] = ds;
		if (ds->drv->poll_link != NULL)
			dst->link_poll_needed = 1;
	}

	/*
	 * If we use a tagging format that doesn't have an ethertype
	 * field, make sure that all packets from this point on get
	 * sent to the tag format's receive function.
	 */
	wmb();
	dev->dsa_ptr = (void *)dst;

	if (dst->link_poll_needed) {
		INIT_WORK(&dst->link_poll_work, dsa_link_poll_work);
		init_timer(&dst->link_poll_timer);
		dst->link_poll_timer.data = (unsigned long)dst;
		dst->link_poll_timer.function = dsa_link_poll_timer;
		dst->link_poll_timer.expires = round_jiffies(jiffies + HZ);
		add_timer(&dst->link_poll_timer);
	}

	return 0;
}

static int dsa_remove(struct platform_device *pdev)
{
	struct dsa_switch_tree *dst = platform_get_drvdata(pdev);
	int i;

	if (dst->link_poll_needed)
		del_timer_sync(&dst->link_poll_timer);

	flush_work_sync(&dst->link_poll_work);

	for (i = 0; i < dst->pd->nr_chips; i++) {
		struct dsa_switch *ds = dst->ds[i];

		if (ds != NULL)
			dsa_switch_destroy(ds);
	}

	return 0;
}

static void dsa_shutdown(struct platform_device *pdev)
{
}

static struct platform_driver dsa_driver = {
	.probe		= dsa_probe,
	.remove		= dsa_remove,
	.shutdown	= dsa_shutdown,
	.driver = {
		.name	= "dsa",
		.owner	= THIS_MODULE,
	},
};

static int __init dsa_init_module(void)
{
	return platform_driver_register(&dsa_driver);
}
module_init(dsa_init_module);

static void __exit dsa_cleanup_module(void)
{
	platform_driver_unregister(&dsa_driver);
}
module_exit(dsa_cleanup_module);

MODULE_AUTHOR("Lennert Buytenhek <buytenh@wantstofly.org>");
MODULE_DESCRIPTION("Driver for Distributed Switch Architecture switch chips");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:dsa");