/*
 * 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 <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_scheduled_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");