/*
 * net/dsa/dsa2.c - Hardware switch handling, binding version 2
 * Copyright (c) 2008-2009 Marvell Semiconductor
 * Copyright (c) 2013 Florian Fainelli <florian@openwrt.org>
 * Copyright (c) 2016 Andrew Lunn <andrew@lunn.ch>
 *
 * 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/device.h>
#include <linux/err.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/rtnetlink.h>
#include <net/dsa.h>
#include <linux/of.h>
#include <linux/of_net.h>
#include "dsa_priv.h"

static LIST_HEAD(dsa_switch_trees);
static DEFINE_MUTEX(dsa2_mutex);

static struct dsa_switch_tree *dsa_get_dst(u32 tree)
{
        struct dsa_switch_tree *dst;

        list_for_each_entry(dst, &dsa_switch_trees, list)
                if (dst->tree == tree) {
                        kref_get(&dst->refcount);
                        return dst;
                }
        return NULL;
}

static void dsa_free_dst(struct kref *ref)
{
        struct dsa_switch_tree *dst = container_of(ref, struct dsa_switch_tree,
                                                   refcount);

        list_del(&dst->list);
        kfree(dst);
}

static void dsa_put_dst(struct dsa_switch_tree *dst)
{
        kref_put(&dst->refcount, dsa_free_dst);
}

static struct dsa_switch_tree *dsa_add_dst(u32 tree)
{
        struct dsa_switch_tree *dst;

        dst = kzalloc(sizeof(*dst), GFP_KERNEL);
        if (!dst)
                return NULL;
        dst->tree = tree;
        dst->cpu_switch = -1;
        INIT_LIST_HEAD(&dst->list);
        list_add_tail(&dsa_switch_trees, &dst->list);
        kref_init(&dst->refcount);

        return dst;
}

static void dsa_dst_add_ds(struct dsa_switch_tree *dst,
                           struct dsa_switch *ds, u32 index)
{
        kref_get(&dst->refcount);
        dst->ds[index] = ds;
}

static void dsa_dst_del_ds(struct dsa_switch_tree *dst,
                           struct dsa_switch *ds, u32 index)
{
        dst->ds[index] = NULL;
        kref_put(&dst->refcount, dsa_free_dst);
}

static bool dsa_port_is_dsa(struct device_node *port)
{
        const char *name;

        name = of_get_property(port, "label", NULL);
        if (!name)
                return false;

        if (!strcmp(name, "dsa"))
                return true;

        return false;
}

static bool dsa_port_is_cpu(struct device_node *port)
{
        const char *name;

        name = of_get_property(port, "label", NULL);
        if (!name)
                return false;

        if (!strcmp(name, "cpu"))
                return true;

        return false;
}

static bool dsa_ds_find_port(struct dsa_switch *ds,
                             struct device_node *port)
{
        u32 index;

        for (index = 0; index < DSA_MAX_PORTS; index++)
                if (ds->ports[index].dn == port)
                        return true;
        return false;
}

static struct dsa_switch *dsa_dst_find_port(struct dsa_switch_tree *dst,
                                            struct device_node *port)
{
        struct dsa_switch *ds;
        u32 index;

        for (index = 0; index < DSA_MAX_SWITCHES; index++) {
                ds = dst->ds[index];
                if (!ds)
                        continue;

                if (dsa_ds_find_port(ds, port))
                        return ds;
        }

        return NULL;
}

static int dsa_port_complete(struct dsa_switch_tree *dst,
                             struct dsa_switch *src_ds,
                             struct device_node *port,
                             u32 src_port)
{
        struct device_node *link;
        int index;
        struct dsa_switch *dst_ds;

        for (index = 0;; index++) {
                link = of_parse_phandle(port, "link", index);
                if (!link)
                        break;

                dst_ds = dsa_dst_find_port(dst, link);
                of_node_put(link);

                if (!dst_ds)
                        return 1;

                src_ds->rtable[dst_ds->index] = src_port;
        }

        return 0;
}

/* A switch is complete if all the DSA ports phandles point to ports
 * known in the tree. A return value of 1 means the tree is not
 * complete. This is not an error condition. A value of 0 is
 * success.
 */
static int dsa_ds_complete(struct dsa_switch_tree *dst, struct dsa_switch *ds)
{
        struct device_node *port;
        u32 index;
        int err;

        for (index = 0; index < DSA_MAX_PORTS; index++) {
                port = ds->ports[index].dn;
                if (!port)
                        continue;

                if (!dsa_port_is_dsa(port))
                        continue;

                err = dsa_port_complete(dst, ds, port, index);
                if (err != 0)
                        return err;

                ds->dsa_port_mask |= BIT(index);
        }

        return 0;
}

/* A tree is complete if all the DSA ports phandles point to ports
 * known in the tree. A return value of 1 means the tree is not
 * complete. This is not an error condition. A value of 0 is
 * success.
 */
static int dsa_dst_complete(struct dsa_switch_tree *dst)
{
        struct dsa_switch *ds;
        u32 index;
        int err;

        for (index = 0; index < DSA_MAX_SWITCHES; index++) {
                ds = dst->ds[index];
                if (!ds)
                        continue;

                err = dsa_ds_complete(dst, ds);
                if (err != 0)
                        return err;
        }

        return 0;
}

static int dsa_dsa_port_apply(struct device_node *port, u32 index,
                              struct dsa_switch *ds)
{
        int err;

        err = dsa_cpu_dsa_setup(ds, ds->dev, port, index);
        if (err) {
                dev_warn(ds->dev, "Failed to setup dsa port %d: %d\n",
                         index, err);
                return err;
        }

        return 0;
}

static void dsa_dsa_port_unapply(struct device_node *port, u32 index,
                                 struct dsa_switch *ds)
{
        dsa_cpu_dsa_destroy(port);
}

static int dsa_cpu_port_apply(struct device_node *port, u32 index,
                              struct dsa_switch *ds)
{
        int err;

        err = dsa_cpu_dsa_setup(ds, ds->dev, port, index);
        if (err) {
                dev_warn(ds->dev, "Failed to setup cpu port %d: %d\n",
                         index, err);
                return err;
        }

        ds->cpu_port_mask |= BIT(index);

        return 0;
}

static void dsa_cpu_port_unapply(struct device_node *port, u32 index,
                                 struct dsa_switch *ds)
{
        dsa_cpu_dsa_destroy(port);
        ds->cpu_port_mask &= ~BIT(index);

}

static int dsa_user_port_apply(struct device_node *port, u32 index,
                               struct dsa_switch *ds)
{
        const char *name;
        int err;

        name = of_get_property(port, "label", NULL);

        err = dsa_slave_create(ds, ds->dev, index, name);
        if (err) {
                dev_warn(ds->dev, "Failed to create slave %d: %d\n",
                         index, err);
                ds->ports[index].netdev = NULL;
                return err;
        }

        return 0;
}

static void dsa_user_port_unapply(struct device_node *port, u32 index,
                                  struct dsa_switch *ds)
{
        if (ds->ports[index].netdev) {
                dsa_slave_destroy(ds->ports[index].netdev);
                ds->ports[index].netdev = NULL;
                ds->enabled_port_mask &= ~(1 << index);
        }
}

static int dsa_ds_apply(struct dsa_switch_tree *dst, struct dsa_switch *ds)
{
        struct device_node *port;
        u32 index;
        int err;

        /* Initialize ds->phys_mii_mask before registering the slave MDIO bus
         * driver and before ops->setup() has run, since the switch drivers and
         * the slave MDIO bus driver rely on these values for probing PHY
         * devices or not
         */
        ds->phys_mii_mask = ds->enabled_port_mask;

        err = ds->ops->setup(ds);
        if (err < 0)
                return err;

        if (ds->ops->set_addr) {
                err = ds->ops->set_addr(ds, dst->master_netdev->dev_addr);
                if (err < 0)
                        return err;
        }

        if (!ds->slave_mii_bus && ds->ops->phy_read) {
                ds->slave_mii_bus = devm_mdiobus_alloc(ds->dev);
                if (!ds->slave_mii_bus)
                        return -ENOMEM;

                dsa_slave_mii_bus_init(ds);

                err = mdiobus_register(ds->slave_mii_bus);
                if (err < 0)
                        return err;
        }

        for (index = 0; index < DSA_MAX_PORTS; index++) {
                port = ds->ports[index].dn;
                if (!port)
                        continue;

                if (dsa_port_is_dsa(port)) {
                        err = dsa_dsa_port_apply(port, index, ds);
                        if (err)
                                return err;
                        continue;
                }

                if (dsa_port_is_cpu(port)) {
                        err = dsa_cpu_port_apply(port, index, ds);
                        if (err)
                                return err;
                        continue;
                }

                err = dsa_user_port_apply(port, index, ds);
                if (err)
                        continue;
        }

        return 0;
}

static void dsa_ds_unapply(struct dsa_switch_tree *dst, struct dsa_switch *ds)
{
        struct device_node *port;
        u32 index;

        for (index = 0; index < DSA_MAX_PORTS; index++) {
                port = ds->ports[index].dn;
                if (!port)
                        continue;

                if (dsa_port_is_dsa(port)) {
                        dsa_dsa_port_unapply(port, index, ds);
                        continue;
                }

                if (dsa_port_is_cpu(port)) {
                        dsa_cpu_port_unapply(port, index, ds);
                        continue;
                }

                dsa_user_port_unapply(port, index, ds);
        }

        if (ds->slave_mii_bus && ds->ops->phy_read)
                mdiobus_unregister(ds->slave_mii_bus);
}

static int dsa_dst_apply(struct dsa_switch_tree *dst)
{
        struct dsa_switch *ds;
        u32 index;
        int err;

        for (index = 0; index < DSA_MAX_SWITCHES; index++) {
                ds = dst->ds[index];
                if (!ds)
                        continue;

                err = dsa_ds_apply(dst, ds);
                if (err)
                        return err;
        }

        if (dst->ds[0]) {
                err = dsa_cpu_port_ethtool_setup(dst->ds[0]);
                if (err)
                        return err;
        }

        /* 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();
        dst->master_netdev->dsa_ptr = (void *)dst;
        dst->applied = true;

        return 0;
}

static void dsa_dst_unapply(struct dsa_switch_tree *dst)
{
        struct dsa_switch *ds;
        u32 index;

        if (!dst->applied)
                return;

        dst->master_netdev->dsa_ptr = NULL;

        /* If we used a tagging format that doesn't have an ethertype
         * field, make sure that all packets from this point get sent
         * without the tag and go through the regular receive path.
         */
        wmb();

        for (index = 0; index < DSA_MAX_SWITCHES; index++) {
                ds = dst->ds[index];
                if (!ds)
                        continue;

                dsa_ds_unapply(dst, ds);
        }

        if (dst->ds[0])
                dsa_cpu_port_ethtool_restore(dst->ds[0]);

        pr_info("DSA: tree %d unapplied\n", dst->tree);
        dst->applied = false;
}

static int dsa_cpu_parse(struct device_node *port, u32 index,
                         struct dsa_switch_tree *dst,
                         struct dsa_switch *ds)
{
        enum dsa_tag_protocol tag_protocol;
        struct net_device *ethernet_dev;
        struct device_node *ethernet;

        ethernet = of_parse_phandle(port, "ethernet", 0);
        if (!ethernet)
                return -EINVAL;

        ethernet_dev = of_find_net_device_by_node(ethernet);
        if (!ethernet_dev)
                return -EPROBE_DEFER;

        if (!ds->master_netdev)
                ds->master_netdev = ethernet_dev;

        if (!dst->master_netdev)
                dst->master_netdev = ethernet_dev;

        if (dst->cpu_switch == -1) {
                dst->cpu_switch = ds->index;
                dst->cpu_port = index;
        }

        tag_protocol = ds->ops->get_tag_protocol(ds);
        dst->tag_ops = dsa_resolve_tag_protocol(tag_protocol);
        if (IS_ERR(dst->tag_ops)) {
                dev_warn(ds->dev, "No tagger for this switch\n");
                return PTR_ERR(dst->tag_ops);
        }

        dst->rcv = dst->tag_ops->rcv;

        return 0;
}

static int dsa_ds_parse(struct dsa_switch_tree *dst, struct dsa_switch *ds)
{
        struct device_node *port;
        u32 index;
        int err;

        for (index = 0; index < DSA_MAX_PORTS; index++) {
                port = ds->ports[index].dn;
                if (!port)
                        continue;

                if (dsa_port_is_cpu(port)) {
                        err = dsa_cpu_parse(port, index, dst, ds);
                        if (err)
                                return err;
                }
        }

        pr_info("DSA: switch %d %d parsed\n", dst->tree, ds->index);

        return 0;
}

static int dsa_dst_parse(struct dsa_switch_tree *dst)
{
        struct dsa_switch *ds;
        u32 index;
        int err;

        for (index = 0; index < DSA_MAX_SWITCHES; index++) {
                ds = dst->ds[index];
                if (!ds)
                        continue;

                err = dsa_ds_parse(dst, ds);
                if (err)
                        return err;
        }

        if (!dst->master_netdev) {
                pr_warn("Tree has no master device\n");
                return -EINVAL;
        }

        pr_info("DSA: tree %d parsed\n", dst->tree);

        return 0;
}

static int dsa_parse_ports_dn(struct device_node *ports, struct dsa_switch *ds)
{
        struct device_node *port;
        int err;
        u32 reg;

        for_each_available_child_of_node(ports, port) {
                err = of_property_read_u32(port, "reg", &reg);
                if (err)
                        return err;

                if (reg >= DSA_MAX_PORTS)
                        return -EINVAL;

                ds->ports[reg].dn = port;

                /* Initialize enabled_port_mask now for ops->setup()
                 * to have access to a correct value, just like what
                 * net/dsa/dsa.c::dsa_switch_setup_one does.
                 */
                if (!dsa_port_is_cpu(port))
                        ds->enabled_port_mask |= 1 << reg;
        }

        return 0;
}

static int dsa_parse_member(struct device_node *np, u32 *tree, u32 *index)
{
        int err;

        *tree = *index = 0;

        err = of_property_read_u32_index(np, "dsa,member", 0, tree);
        if (err) {
                /* Does not exist, but it is optional */
                if (err == -EINVAL)
                        return 0;
                return err;
        }

        err = of_property_read_u32_index(np, "dsa,member", 1, index);
        if (err)
                return err;

        if (*index >= DSA_MAX_SWITCHES)
                return -EINVAL;

        return 0;
}

static struct device_node *dsa_get_ports(struct dsa_switch *ds,
                                         struct device_node *np)
{
        struct device_node *ports;

        ports = of_get_child_by_name(np, "ports");
        if (!ports) {
                dev_err(ds->dev, "no ports child node found\n");
                return ERR_PTR(-EINVAL);
        }

        return ports;
}

static int _dsa_register_switch(struct dsa_switch *ds, struct device_node *np)
{
        struct device_node *ports = dsa_get_ports(ds, np);
        struct dsa_switch_tree *dst;
        u32 tree, index;
        int i, err;

        err = dsa_parse_member(np, &tree, &index);
        if (err)
                return err;

        if (IS_ERR(ports))
                return PTR_ERR(ports);

        err = dsa_parse_ports_dn(ports, ds);
        if (err)
                return err;

        dst = dsa_get_dst(tree);
        if (!dst) {
                dst = dsa_add_dst(tree);
                if (!dst)
                        return -ENOMEM;
        }

        if (dst->ds[index]) {
                err = -EBUSY;
                goto out;
        }

        ds->dst = dst;
        ds->index = index;

        /* Initialize the routing table */
        for (i = 0; i < DSA_MAX_SWITCHES; ++i)
                ds->rtable[i] = DSA_RTABLE_NONE;

        dsa_dst_add_ds(dst, ds, index);

        err = dsa_dst_complete(dst);
        if (err < 0)
                goto out_del_dst;

        if (err == 1) {
                /* Not all switches registered yet */
                err = 0;
                goto out;
        }

        if (dst->applied) {
                pr_info("DSA: Disjoint trees?\n");
                return -EINVAL;
        }

        err = dsa_dst_parse(dst);
        if (err)
                goto out_del_dst;

        err = dsa_dst_apply(dst);
        if (err) {
                dsa_dst_unapply(dst);
                goto out_del_dst;
        }

        dsa_put_dst(dst);
        return 0;

out_del_dst:
        dsa_dst_del_ds(dst, ds, ds->index);
out:
        dsa_put_dst(dst);

        return err;
}

int dsa_register_switch(struct dsa_switch *ds, struct device_node *np)
{
        int err;

        mutex_lock(&dsa2_mutex);
        err = _dsa_register_switch(ds, np);
        mutex_unlock(&dsa2_mutex);

        return err;
}
EXPORT_SYMBOL_GPL(dsa_register_switch);

static void _dsa_unregister_switch(struct dsa_switch *ds)
{
        struct dsa_switch_tree *dst = ds->dst;

        dsa_dst_unapply(dst);

        dsa_dst_del_ds(dst, ds, ds->index);
}

void dsa_unregister_switch(struct dsa_switch *ds)
{
        mutex_lock(&dsa2_mutex);
        _dsa_unregister_switch(ds);
        mutex_unlock(&dsa2_mutex);
}
EXPORT_SYMBOL_GPL(dsa_unregister_switch);