/*
 * 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/netdevice.h>
#include <linux/slab.h>
#include <linux/rtnetlink.h>
#include <linux/of.h>
#include <linux/of_net.h>

#include "dsa_priv.h"

static LIST_HEAD(dsa_tree_list);
static DEFINE_MUTEX(dsa2_mutex);

static const struct devlink_ops dsa_devlink_ops = {
};

static struct dsa_switch_tree *dsa_tree_find(int index)
{
        struct dsa_switch_tree *dst;

        list_for_each_entry(dst, &dsa_tree_list, list)
                if (dst->index == index)
                        return dst;

        return NULL;
}

static struct dsa_switch_tree *dsa_tree_alloc(int index)
{
        struct dsa_switch_tree *dst;

        dst = kzalloc(sizeof(*dst), GFP_KERNEL);
        if (!dst)
                return NULL;

        dst->index = index;

        INIT_LIST_HEAD(&dst->list);
        list_add_tail(&dsa_tree_list, &dst->list);

        kref_init(&dst->refcount);

        return dst;
}

static void dsa_tree_free(struct dsa_switch_tree *dst)
{
        list_del(&dst->list);
        kfree(dst);
}

static struct dsa_switch_tree *dsa_tree_get(struct dsa_switch_tree *dst)
{
        if (dst)
                kref_get(&dst->refcount);

        return dst;
}

static struct dsa_switch_tree *dsa_tree_touch(int index)
{
        struct dsa_switch_tree *dst;

        dst = dsa_tree_find(index);
        if (dst)
                return dsa_tree_get(dst);
        else
                return dsa_tree_alloc(index);
}

static void dsa_tree_release(struct kref *ref)
{
        struct dsa_switch_tree *dst;

        dst = container_of(ref, struct dsa_switch_tree, refcount);

        dsa_tree_free(dst);
}

static void dsa_tree_put(struct dsa_switch_tree *dst)
{
        if (dst)
                kref_put(&dst->refcount, dsa_tree_release);
}

static bool dsa_port_is_dsa(struct dsa_port *port)
{
        return port->type == DSA_PORT_TYPE_DSA;
}

static bool dsa_port_is_cpu(struct dsa_port *port)
{
        return port->type == DSA_PORT_TYPE_CPU;
}

static bool dsa_port_is_user(struct dsa_port *dp)
{
        return dp->type == DSA_PORT_TYPE_USER;
}

static struct dsa_port *dsa_tree_find_port_by_node(struct dsa_switch_tree *dst,
                                                   struct device_node *dn)
{
        struct dsa_switch *ds;
        struct dsa_port *dp;
        int device, port;

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

                for (port = 0; port < ds->num_ports; port++) {
                        dp = &ds->ports[port];

                        if (dp->dn == dn)
                                return dp;
                }
        }

        return NULL;
}

static bool dsa_port_setup_routing_table(struct dsa_port *dp)
{
        struct dsa_switch *ds = dp->ds;
        struct dsa_switch_tree *dst = ds->dst;
        struct device_node *dn = dp->dn;
        struct of_phandle_iterator it;
        struct dsa_port *link_dp;
        int err;

        of_for_each_phandle(&it, err, dn, "link", NULL, 0) {
                link_dp = dsa_tree_find_port_by_node(dst, it.node);
                if (!link_dp) {
                        of_node_put(it.node);
                        return false;
                }

                ds->rtable[link_dp->ds->index] = dp->index;
        }

        return true;
}

static bool dsa_switch_setup_routing_table(struct dsa_switch *ds)
{
        bool complete = true;
        struct dsa_port *dp;
        int i;

        for (i = 0; i < DSA_MAX_SWITCHES; i++)
                ds->rtable[i] = DSA_RTABLE_NONE;

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

                if (dsa_port_is_dsa(dp)) {
                        complete = dsa_port_setup_routing_table(dp);
                        if (!complete)
                                break;
                }
        }

        return complete;
}

static bool dsa_tree_setup_routing_table(struct dsa_switch_tree *dst)
{
        struct dsa_switch *ds;
        bool complete = true;
        int device;

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

                complete = dsa_switch_setup_routing_table(ds);
                if (!complete)
                        break;
        }

        return complete;
}

static struct dsa_port *dsa_tree_find_first_cpu(struct dsa_switch_tree *dst)
{
        struct dsa_switch *ds;
        struct dsa_port *dp;
        int device, port;

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

                for (port = 0; port < ds->num_ports; port++) {
                        dp = &ds->ports[port];

                        if (dsa_port_is_cpu(dp))
                                return dp;
                }
        }

        return NULL;
}

static int dsa_tree_setup_default_cpu(struct dsa_switch_tree *dst)
{
        struct dsa_switch *ds;
        struct dsa_port *dp;
        int device, port;

        /* DSA currently only supports a single CPU port */
        dst->cpu_dp = dsa_tree_find_first_cpu(dst);
        if (!dst->cpu_dp) {
                pr_warn("Tree has no master device\n");
                return -EINVAL;
        }

        /* Assign the default CPU port to all ports of the fabric */
        for (device = 0; device < DSA_MAX_SWITCHES; device++) {
                ds = dst->ds[device];
                if (!ds)
                        continue;

                for (port = 0; port < ds->num_ports; port++) {
                        dp = &ds->ports[port];

                        if (dsa_port_is_user(dp) || dsa_port_is_dsa(dp))
                                dp->cpu_dp = dst->cpu_dp;
                }
        }

        return 0;
}

static void dsa_tree_teardown_default_cpu(struct dsa_switch_tree *dst)
{
        /* DSA currently only supports a single CPU port */
        dst->cpu_dp = NULL;
}

static int dsa_port_setup(struct dsa_port *dp)
{
        struct dsa_switch *ds = dp->ds;
        int err;

        memset(&dp->devlink_port, 0, sizeof(dp->devlink_port));

        err = devlink_port_register(ds->devlink, &dp->devlink_port, dp->index);
        if (err)
                return err;

        switch (dp->type) {
        case DSA_PORT_TYPE_UNUSED:
                break;
        case DSA_PORT_TYPE_CPU:
        case DSA_PORT_TYPE_DSA:
                err = dsa_port_link_register_of(dp);
                if (err) {
                        dev_err(ds->dev, "failed to setup link for port %d.%d\n",
                                ds->index, dp->index);
                        return err;
                }
                break;
        case DSA_PORT_TYPE_USER:
                err = dsa_slave_create(dp);
                if (err)
                        dev_err(ds->dev, "failed to create slave for port %d.%d\n",
                                ds->index, dp->index);
                else
                        devlink_port_type_eth_set(&dp->devlink_port, dp->slave);
                break;
        }

        return 0;
}

static void dsa_port_teardown(struct dsa_port *dp)
{
        devlink_port_unregister(&dp->devlink_port);

        switch (dp->type) {
        case DSA_PORT_TYPE_UNUSED:
                break;
        case DSA_PORT_TYPE_CPU:
        case DSA_PORT_TYPE_DSA:
                dsa_port_link_unregister_of(dp);
                break;
        case DSA_PORT_TYPE_USER:
                if (dp->slave) {
                        dsa_slave_destroy(dp->slave);
                        dp->slave = NULL;
                }
                break;
        }
}

static int dsa_switch_setup(struct dsa_switch *ds)
{
        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 |= dsa_user_ports(ds);

        /* Add the switch to devlink before calling setup, so that setup can
         * add dpipe tables
         */
        ds->devlink = devlink_alloc(&dsa_devlink_ops, 0);
        if (!ds->devlink)
                return -ENOMEM;

        err = devlink_register(ds->devlink, ds->dev);
        if (err)
                return err;

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

        err = dsa_switch_register_notifier(ds);
        if (err)
                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;
        }

        return 0;
}

static void dsa_switch_teardown(struct dsa_switch *ds)
{
        if (ds->slave_mii_bus && ds->ops->phy_read)
                mdiobus_unregister(ds->slave_mii_bus);

        dsa_switch_unregister_notifier(ds);

        if (ds->devlink) {
                devlink_unregister(ds->devlink);
                devlink_free(ds->devlink);
                ds->devlink = NULL;
        }

}

static int dsa_tree_setup_switches(struct dsa_switch_tree *dst)
{
        struct dsa_switch *ds;
        struct dsa_port *dp;
        int device, port;
        int err;

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

                err = dsa_switch_setup(ds);
                if (err)
                        return err;

                for (port = 0; port < ds->num_ports; port++) {
                        dp = &ds->ports[port];

                        err = dsa_port_setup(dp);
                        if (err)
                                return err;
                }
        }

        return 0;
}

static void dsa_tree_teardown_switches(struct dsa_switch_tree *dst)
{
        struct dsa_switch *ds;
        struct dsa_port *dp;
        int device, port;

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

                for (port = 0; port < ds->num_ports; port++) {
                        dp = &ds->ports[port];

                        dsa_port_teardown(dp);
                }

                dsa_switch_teardown(ds);
        }
}

static int dsa_tree_setup_master(struct dsa_switch_tree *dst)
{
        struct dsa_port *cpu_dp = dst->cpu_dp;
        struct net_device *master = cpu_dp->master;

        /* DSA currently supports a single pair of CPU port and master device */
        return dsa_master_setup(master, cpu_dp);
}

static void dsa_tree_teardown_master(struct dsa_switch_tree *dst)
{
        struct dsa_port *cpu_dp = dst->cpu_dp;
        struct net_device *master = cpu_dp->master;

        return dsa_master_teardown(master);
}

static int dsa_tree_setup(struct dsa_switch_tree *dst)
{
        bool complete;
        int err;

        if (dst->setup) {
                pr_err("DSA: tree %d already setup! Disjoint trees?\n",
                       dst->index);
                return -EEXIST;
        }

        complete = dsa_tree_setup_routing_table(dst);
        if (!complete)
                return 0;

        err = dsa_tree_setup_default_cpu(dst);
        if (err)
                return err;

        err = dsa_tree_setup_switches(dst);
        if (err)
                return err;

        err = dsa_tree_setup_master(dst);
        if (err)
                return err;

        dst->setup = true;

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

        return 0;
}

static void dsa_tree_teardown(struct dsa_switch_tree *dst)
{
        if (!dst->setup)
                return;

        dsa_tree_teardown_master(dst);

        dsa_tree_teardown_switches(dst);

        dsa_tree_teardown_default_cpu(dst);

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

        dst->setup = false;
}

static void dsa_tree_remove_switch(struct dsa_switch_tree *dst,
                                   unsigned int index)
{
        dsa_tree_teardown(dst);

        dst->ds[index] = NULL;
        dsa_tree_put(dst);
}

static int dsa_tree_add_switch(struct dsa_switch_tree *dst,
                               struct dsa_switch *ds)
{
        unsigned int index = ds->index;
        int err;

        if (dst->ds[index])
                return -EBUSY;

        dsa_tree_get(dst);
        dst->ds[index] = ds;

        err = dsa_tree_setup(dst);
        if (err)
                dsa_tree_remove_switch(dst, index);

        return err;
}

static int dsa_port_parse_user(struct dsa_port *dp, const char *name)
{
        if (!name)
                name = "eth%d";

        dp->type = DSA_PORT_TYPE_USER;
        dp->name = name;

        return 0;
}

static int dsa_port_parse_dsa(struct dsa_port *dp)
{
        dp->type = DSA_PORT_TYPE_DSA;

        return 0;
}

static int dsa_port_parse_cpu(struct dsa_port *dp, struct net_device *master)
{
        struct dsa_switch *ds = dp->ds;
        struct dsa_switch_tree *dst = ds->dst;
        const struct dsa_device_ops *tag_ops;
        enum dsa_tag_protocol tag_protocol;

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

        dp->type = DSA_PORT_TYPE_CPU;
        dp->rcv = tag_ops->rcv;
        dp->tag_ops = tag_ops;
        dp->master = master;
        dp->dst = dst;

        return 0;
}

static int dsa_port_parse_of(struct dsa_port *dp, struct device_node *dn)
{
        struct device_node *ethernet = of_parse_phandle(dn, "ethernet", 0);
        const char *name = of_get_property(dn, "label", NULL);
        bool link = of_property_read_bool(dn, "link");

        dp->dn = dn;

        if (ethernet) {
                struct net_device *master;

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

                return dsa_port_parse_cpu(dp, master);
        }

        if (link)
                return dsa_port_parse_dsa(dp);

        return dsa_port_parse_user(dp, name);
}

static int dsa_switch_parse_ports_of(struct dsa_switch *ds,
                                     struct device_node *dn)
{
        struct device_node *ports, *port;
        struct dsa_port *dp;
        u32 reg;
        int err;

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

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

                if (reg >= ds->num_ports)
                        return -EINVAL;

                dp = &ds->ports[reg];

                err = dsa_port_parse_of(dp, port);
                if (err)
                        return err;
        }

        return 0;
}

static int dsa_switch_parse_member_of(struct dsa_switch *ds,
                                      struct device_node *dn)
{
        u32 m[2] = { 0, 0 };
        int sz;

        /* Don't error out if this optional property isn't found */
        sz = of_property_read_variable_u32_array(dn, "dsa,member", m, 2, 2);
        if (sz < 0 && sz != -EINVAL)
                return sz;

        ds->index = m[1];
        if (ds->index >= DSA_MAX_SWITCHES)
                return -EINVAL;

        ds->dst = dsa_tree_touch(m[0]);
        if (!ds->dst)
                return -ENOMEM;

        return 0;
}

static int dsa_switch_parse_of(struct dsa_switch *ds, struct device_node *dn)
{
        int err;

        err = dsa_switch_parse_member_of(ds, dn);
        if (err)
                return err;

        return dsa_switch_parse_ports_of(ds, dn);
}

static int dsa_port_parse(struct dsa_port *dp, const char *name,
                          struct device *dev)
{
        if (!strcmp(name, "cpu")) {
                struct net_device *master;

                master = dsa_dev_to_net_device(dev);
                if (!master)
                        return -EPROBE_DEFER;

                dev_put(master);

                return dsa_port_parse_cpu(dp, master);
        }

        if (!strcmp(name, "dsa"))
                return dsa_port_parse_dsa(dp);

        return dsa_port_parse_user(dp, name);
}

static int dsa_switch_parse_ports(struct dsa_switch *ds,
                                  struct dsa_chip_data *cd)
{
        bool valid_name_found = false;
        struct dsa_port *dp;
        struct device *dev;
        const char *name;
        unsigned int i;
        int err;

        for (i = 0; i < DSA_MAX_PORTS; i++) {
                name = cd->port_names[i];
                dev = cd->netdev[i];
                dp = &ds->ports[i];

                if (!name)
                        continue;

                err = dsa_port_parse(dp, name, dev);
                if (err)
                        return err;

                valid_name_found = true;
        }

        if (!valid_name_found && i == DSA_MAX_PORTS)
                return -EINVAL;

        return 0;
}

static int dsa_switch_parse(struct dsa_switch *ds, struct dsa_chip_data *cd)
{
        ds->cd = cd;

        /* We don't support interconnected switches nor multiple trees via
         * platform data, so this is the unique switch of the tree.
         */
        ds->index = 0;
        ds->dst = dsa_tree_touch(0);
        if (!ds->dst)
                return -ENOMEM;

        return dsa_switch_parse_ports(ds, cd);
}

static int dsa_switch_add(struct dsa_switch *ds)
{
        struct dsa_switch_tree *dst = ds->dst;

        return dsa_tree_add_switch(dst, ds);
}

static int dsa_switch_probe(struct dsa_switch *ds)
{
        struct dsa_chip_data *pdata = ds->dev->platform_data;
        struct device_node *np = ds->dev->of_node;
        int err;

        if (np)
                err = dsa_switch_parse_of(ds, np);
        else if (pdata)
                err = dsa_switch_parse(ds, pdata);
        else
                err = -ENODEV;

        if (err)
                return err;

        return dsa_switch_add(ds);
}

struct dsa_switch *dsa_switch_alloc(struct device *dev, size_t n)
{
        size_t size = sizeof(struct dsa_switch) + n * sizeof(struct dsa_port);
        struct dsa_switch *ds;
        int i;

        ds = devm_kzalloc(dev, size, GFP_KERNEL);
        if (!ds)
                return NULL;

        ds->dev = dev;
        ds->num_ports = n;

        for (i = 0; i < ds->num_ports; ++i) {
                ds->ports[i].index = i;
                ds->ports[i].ds = ds;
        }

        return ds;
}
EXPORT_SYMBOL_GPL(dsa_switch_alloc);

int dsa_register_switch(struct dsa_switch *ds)
{
        int err;

        mutex_lock(&dsa2_mutex);
        err = dsa_switch_probe(ds);
        dsa_tree_put(ds->dst);
        mutex_unlock(&dsa2_mutex);

        return err;
}
EXPORT_SYMBOL_GPL(dsa_register_switch);

static void dsa_switch_remove(struct dsa_switch *ds)
{
        struct dsa_switch_tree *dst = ds->dst;
        unsigned int index = ds->index;

        dsa_tree_remove_switch(dst, index);
}

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