// SPDX-License-Identifier: GPL-2.0+
/*
 * Infrastructure to handle all PHY devices connected to a given netdev,
 * either directly or indirectly attached.
 *
 * Copyright (c) 2023 Maxime Chevallier<maxime.chevallier@bootlin.com>
 */

#include <linux/phy_link_topology.h>
#include <linux/phy.h>
#include <linux/rtnetlink.h>
#include <linux/xarray.h>

static int netdev_alloc_phy_link_topology(struct net_device *dev)
{
        struct phy_link_topology *topo;

        topo = kzalloc_obj(*topo);
        if (!topo)
                return -ENOMEM;

        xa_init_flags(&topo->phys, XA_FLAGS_ALLOC1);
        topo->next_phy_index = 1;

        dev->link_topo = topo;

        return 0;
}

int phy_link_topo_add_phy(struct net_device *dev,
                          struct phy_device *phy,
                          enum phy_upstream upt, void *upstream)
{
        struct phy_link_topology *topo = dev->link_topo;
        struct phy_device_node *pdn;
        int ret;

        if (!topo) {
                ret = netdev_alloc_phy_link_topology(dev);
                if (ret)
                        return ret;

                topo = dev->link_topo;
        }

        pdn = kzalloc_obj(*pdn);
        if (!pdn)
                return -ENOMEM;

        pdn->phy = phy;
        switch (upt) {
        case PHY_UPSTREAM_MAC:
                pdn->upstream.netdev = (struct net_device *)upstream;
                if (phy_on_sfp(phy))
                        pdn->parent_sfp_bus = pdn->upstream.netdev->sfp_bus;
                break;
        case PHY_UPSTREAM_PHY:
                pdn->upstream.phydev = (struct phy_device *)upstream;
                if (phy_on_sfp(phy))
                        pdn->parent_sfp_bus = pdn->upstream.phydev->sfp_bus;
                break;
        default:
                ret = -EINVAL;
                goto err;
        }
        pdn->upstream_type = upt;

        /* Attempt to re-use a previously allocated phy_index */
        if (phy->phyindex)
                ret = xa_insert(&topo->phys, phy->phyindex, pdn, GFP_KERNEL);
        else
                ret = xa_alloc_cyclic(&topo->phys, &phy->phyindex, pdn,
                                      xa_limit_32b, &topo->next_phy_index,
                                      GFP_KERNEL);

        if (ret < 0)
                goto err;

        return 0;

err:
        kfree(pdn);
        return ret;
}
EXPORT_SYMBOL_GPL(phy_link_topo_add_phy);

void phy_link_topo_del_phy(struct net_device *dev,
                           struct phy_device *phy)
{
        struct phy_link_topology *topo = dev->link_topo;
        struct phy_device_node *pdn;

        if (!topo)
                return;

        pdn = xa_erase(&topo->phys, phy->phyindex);

        /* We delete the PHY from the topology, however we don't re-set the
         * phy->phyindex field. If the PHY isn't gone, we can re-assign it the
         * same index next time it's added back to the topology
         */

        kfree(pdn);
}
EXPORT_SYMBOL_GPL(phy_link_topo_del_phy);