// SPDX-License-Identifier: GPL-2.0-only
/*
 * OF helpers for the MDIO (Ethernet PHY) API
 *
 * Copyright (c) 2009 Secret Lab Technologies, Ltd.
 *
 * This file provides helper functions for extracting PHY device information
 * out of the OpenFirmware device tree and using it to populate an mii_bus.
 */

#include <linux/device.h>
#include <linux/err.h>
#include <linux/fwnode_mdio.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/of_mdio.h>
#include <linux/of_net.h>
#include <linux/phy.h>
#include <linux/phy_fixed.h>

#define DEFAULT_GPIO_RESET_DELAY        10      /* in microseconds */

MODULE_AUTHOR("Grant Likely <grant.likely@secretlab.ca>");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("OpenFirmware MDIO bus (Ethernet PHY) accessors");

/* Extract the clause 22 phy ID from the compatible string of the form
 * ethernet-phy-idAAAA.BBBB */
static int of_get_phy_id(struct device_node *device, u32 *phy_id)
{
        return fwnode_get_phy_id(of_fwnode_handle(device), phy_id);
}

int of_mdiobus_phy_device_register(struct mii_bus *mdio, struct phy_device *phy,
                                   struct device_node *child, u32 addr)
{
        return fwnode_mdiobus_phy_device_register(mdio, phy,
                                                  of_fwnode_handle(child),
                                                  addr);
}
EXPORT_SYMBOL(of_mdiobus_phy_device_register);

static int of_mdiobus_register_phy(struct mii_bus *mdio,
                                    struct device_node *child, u32 addr)
{
        return fwnode_mdiobus_register_phy(mdio, of_fwnode_handle(child), addr);
}

static int of_mdiobus_register_device(struct mii_bus *mdio,
                                      struct device_node *child, u32 addr)
{
        struct fwnode_handle *fwnode = of_fwnode_handle(child);
        struct mdio_device *mdiodev;
        int rc;

        mdiodev = mdio_device_create(mdio, addr);
        if (IS_ERR(mdiodev))
                return PTR_ERR(mdiodev);

        /* Associate the OF node with the device structure so it
         * can be looked up later.
         */
        device_set_node(&mdiodev->dev, fwnode_handle_get(fwnode));

        /* All data is now stored in the mdiodev struct; register it. */
        rc = mdio_device_register(mdiodev);
        if (rc) {
                mdio_device_free(mdiodev);
                return rc;
        }

        dev_dbg(&mdio->dev, "registered mdio device %pOFn at address %i\n",
                child, addr);
        return 0;
}

/* The following is a list of PHY compatible strings which appear in
 * some DTBs. The compatible string is never matched against a PHY
 * driver, so is pointless. We only expect devices which are not PHYs
 * to have a compatible string, so they can be matched to an MDIO
 * driver.  Encourage users to upgrade their DT blobs to remove these.
 */
static const struct of_device_id whitelist_phys[] = {
        { .compatible = "brcm,40nm-ephy" },
        { .compatible = "broadcom,bcm5241" },
        { .compatible = "marvell,88E1111", },
        { .compatible = "marvell,88e1116", },
        { .compatible = "marvell,88e1118", },
        { .compatible = "marvell,88e1145", },
        { .compatible = "marvell,88e1149r", },
        { .compatible = "marvell,88e1310", },
        { .compatible = "marvell,88E1510", },
        { .compatible = "marvell,88E1514", },
        { .compatible = "moxa,moxart-rtl8201cp", },
        {}
};

/*
 * Return true if the child node is for a phy. It must either:
 * o Compatible string of "ethernet-phy-idX.X"
 * o Compatible string of "ethernet-phy-ieee802.3-c45"
 * o Compatible string of "ethernet-phy-ieee802.3-c22"
 * o In the white list above (and issue a warning)
 * o No compatibility string
 *
 * A device which is not a phy is expected to have a compatible string
 * indicating what sort of device it is.
 */
bool of_mdiobus_child_is_phy(struct device_node *child)
{
        u32 phy_id;

        if (of_get_phy_id(child, &phy_id) != -EINVAL)
                return true;

        if (of_device_is_compatible(child, "ethernet-phy-ieee802.3-c45"))
                return true;

        if (of_device_is_compatible(child, "ethernet-phy-ieee802.3-c22"))
                return true;

        if (of_match_node(whitelist_phys, child)) {
                pr_warn(FW_WARN
                        "%pOF: Whitelisted compatible string. Please remove\n",
                        child);
                return true;
        }

        if (!of_property_present(child, "compatible"))
                return true;

        return false;
}
EXPORT_SYMBOL(of_mdiobus_child_is_phy);

static int __of_mdiobus_parse_phys(struct mii_bus *mdio, struct device_node *np,
                                   bool *scanphys)
{
        struct device_node *child;
        int addr, rc = 0;

        /* Loop over the child nodes and register a phy_device for each phy */
        for_each_available_child_of_node(np, child) {
                if (of_node_name_eq(child, "ethernet-phy-package")) {
                        /* Ignore invalid ethernet-phy-package node */
                        if (!of_property_present(child, "reg"))
                                continue;

                        rc = __of_mdiobus_parse_phys(mdio, child, NULL);
                        if (rc && rc != -ENODEV)
                                goto exit;

                        continue;
                }

                addr = of_mdio_parse_addr(&mdio->dev, child);
                if (addr < 0) {
                        /* Skip scanning for invalid ethernet-phy-package node */
                        if (scanphys)
                                *scanphys = true;
                        continue;
                }

                if (of_mdiobus_child_is_phy(child))
                        rc = of_mdiobus_register_phy(mdio, child, addr);
                else
                        rc = of_mdiobus_register_device(mdio, child, addr);

                if (rc == -ENODEV)
                        dev_err(&mdio->dev,
                                "MDIO device at address %d is missing.\n",
                                addr);
                else if (rc)
                        goto exit;
        }

        return 0;
exit:
        of_node_put(child);
        return rc;
}

/**
 * __of_mdiobus_register - Register mii_bus and create PHYs from the device tree
 * @mdio: pointer to mii_bus structure
 * @np: pointer to device_node of MDIO bus.
 * @owner: module owning the @mdio object.
 *
 * This function registers the mii_bus structure and registers a phy_device
 * for each child node of @np.
 */
int __of_mdiobus_register(struct mii_bus *mdio, struct device_node *np,
                          struct module *owner)
{
        struct device_node *child;
        bool scanphys = false;
        int addr, rc;

        if (!np)
                return __mdiobus_register(mdio, owner);

        /* Do not continue if the node is disabled */
        if (!of_device_is_available(np))
                return -ENODEV;

        /* Mask out all PHYs from auto probing.  Instead the PHYs listed in
         * the device tree are populated after the bus has been registered */
        mdio->phy_mask = ~0;

        device_set_node(&mdio->dev, of_fwnode_handle(np));

        /* Get bus level PHY reset GPIO details */
        mdio->reset_delay_us = DEFAULT_GPIO_RESET_DELAY;
        of_property_read_u32(np, "reset-delay-us", &mdio->reset_delay_us);
        mdio->reset_post_delay_us = 0;
        of_property_read_u32(np, "reset-post-delay-us", &mdio->reset_post_delay_us);

        /* Register the MDIO bus */
        rc = __mdiobus_register(mdio, owner);
        if (rc)
                return rc;

        /* Loop over the child nodes and register a phy_device for each phy */
        rc = __of_mdiobus_parse_phys(mdio, np, &scanphys);
        if (rc)
                goto unregister;

        if (!scanphys)
                return 0;

        /* auto scan for PHYs with empty reg property */
        for_each_available_child_of_node(np, child) {
                /* Skip PHYs with reg property set or ethernet-phy-package node */
                if (of_property_present(child, "reg") ||
                    of_node_name_eq(child, "ethernet-phy-package"))
                        continue;

                for (addr = 0; addr < PHY_MAX_ADDR; addr++) {
                        /* skip already registered PHYs */
                        if (mdiobus_is_registered_device(mdio, addr))
                                continue;

                        /* be noisy to encourage people to set reg property */
                        dev_info(&mdio->dev, "scan phy %pOFn at address %i\n",
                                 child, addr);

                        if (of_mdiobus_child_is_phy(child)) {
                                /* -ENODEV is the return code that PHYLIB has
                                 * standardized on to indicate that bus
                                 * scanning should continue.
                                 */
                                rc = of_mdiobus_register_phy(mdio, child, addr);
                                if (!rc)
                                        break;
                                if (rc != -ENODEV)
                                        goto put_unregister;
                        }
                }
        }

        return 0;

put_unregister:
        of_node_put(child);
unregister:
        mdiobus_unregister(mdio);
        return rc;
}
EXPORT_SYMBOL(__of_mdiobus_register);

/**
 * of_mdio_find_device - Given a device tree node, find the mdio_device
 * @np: pointer to the mdio_device's device tree node
 *
 * If successful, returns a pointer to the mdio_device with the embedded
 * struct device refcount incremented by one, or NULL on failure.
 * The caller should call put_device() on the mdio_device after its use
 */
struct mdio_device *of_mdio_find_device(struct device_node *np)
{
        return fwnode_mdio_find_device(of_fwnode_handle(np));
}
EXPORT_SYMBOL(of_mdio_find_device);

/**
 * of_phy_find_device - Give a PHY node, find the phy_device
 * @phy_np: Pointer to the phy's device tree node
 *
 * If successful, returns a pointer to the phy_device with the embedded
 * struct device refcount incremented by one, or NULL on failure.
 */
struct phy_device *of_phy_find_device(struct device_node *phy_np)
{
        return fwnode_phy_find_device(of_fwnode_handle(phy_np));
}
EXPORT_SYMBOL(of_phy_find_device);

/**
 * of_phy_connect - Connect to the phy described in the device tree
 * @dev: pointer to net_device claiming the phy
 * @phy_np: Pointer to device tree node for the PHY
 * @hndlr: Link state callback for the network device
 * @flags: flags to pass to the PHY
 * @iface: PHY data interface type
 *
 * If successful, returns a pointer to the phy_device with the embedded
 * struct device refcount incremented by one, or NULL on failure. The
 * refcount must be dropped by calling phy_disconnect() or phy_detach().
 */
struct phy_device *of_phy_connect(struct net_device *dev,
                                  struct device_node *phy_np,
                                  void (*hndlr)(struct net_device *), u32 flags,
                                  phy_interface_t iface)
{
        struct phy_device *phy = of_phy_find_device(phy_np);
        int ret;

        if (!phy)
                return NULL;

        phy->dev_flags |= flags;

        ret = phy_connect_direct(dev, phy, hndlr, iface);

        /* refcount is held by phy_connect_direct() on success */
        put_device(&phy->mdio.dev);

        return ret ? NULL : phy;
}
EXPORT_SYMBOL(of_phy_connect);

/**
 * of_phy_get_and_connect
 * - Get phy node and connect to the phy described in the device tree
 * @dev: pointer to net_device claiming the phy
 * @np: Pointer to device tree node for the net_device claiming the phy
 * @hndlr: Link state callback for the network device
 *
 * If successful, returns a pointer to the phy_device with the embedded
 * struct device refcount incremented by one, or NULL on failure. The
 * refcount must be dropped by calling phy_disconnect() or phy_detach().
 */
struct phy_device *of_phy_get_and_connect(struct net_device *dev,
                                          struct device_node *np,
                                          void (*hndlr)(struct net_device *))
{
        phy_interface_t iface;
        struct device_node *phy_np;
        struct phy_device *phy;
        int ret;

        ret = of_get_phy_mode(np, &iface);
        if (ret)
                return NULL;
        if (of_phy_is_fixed_link(np)) {
                ret = of_phy_register_fixed_link(np);
                if (ret < 0) {
                        netdev_err(dev, "broken fixed-link specification\n");
                        return NULL;
                }
                phy_np = of_node_get(np);
        } else {
                phy_np = of_parse_phandle(np, "phy-handle", 0);
                if (!phy_np)
                        return NULL;
        }

        phy = of_phy_connect(dev, phy_np, hndlr, 0, iface);

        of_node_put(phy_np);

        return phy;
}
EXPORT_SYMBOL(of_phy_get_and_connect);

/*
 * of_phy_is_fixed_link() and of_phy_register_fixed_link() must
 * support two DT bindings:
 * - the old DT binding, where 'fixed-link' was a property with 5
 *   cells encoding various information about the fixed PHY
 * - the new DT binding, where 'fixed-link' is a sub-node of the
 *   Ethernet device.
 */
bool of_phy_is_fixed_link(struct device_node *np)
{
        struct device_node *dn;
        int err;
        const char *managed;

        /* New binding */
        dn = of_get_child_by_name(np, "fixed-link");
        if (dn) {
                of_node_put(dn);
                return true;
        }

        err = of_property_read_string(np, "managed", &managed);
        if (err == 0 && strcmp(managed, "auto") != 0)
                return true;

        /* Old binding */
        if (of_property_count_u32_elems(np, "fixed-link") == 5)
                return true;

        return false;
}
EXPORT_SYMBOL(of_phy_is_fixed_link);

int of_phy_register_fixed_link(struct device_node *np)
{
        struct fixed_phy_status status = {};
        struct device_node *fixed_link_node;
        u32 fixed_link_prop[5];
        const char *managed;

        if (of_property_read_string(np, "managed", &managed) == 0 &&
            strcmp(managed, "in-band-status") == 0) {
                /* status is zeroed, namely its .link member */
                goto register_phy;
        }

        /* New binding */
        fixed_link_node = of_get_child_by_name(np, "fixed-link");
        if (fixed_link_node) {
                status.link = 1;
                status.duplex = of_property_read_bool(fixed_link_node,
                                                      "full-duplex");
                if (of_property_read_u32(fixed_link_node, "speed",
                                         &status.speed)) {
                        of_node_put(fixed_link_node);
                        return -EINVAL;
                }
                status.pause = of_property_read_bool(fixed_link_node, "pause");
                status.asym_pause = of_property_read_bool(fixed_link_node,
                                                          "asym-pause");
                of_node_put(fixed_link_node);

                goto register_phy;
        }

        /* Old binding */
        if (of_property_read_u32_array(np, "fixed-link", fixed_link_prop,
                                       ARRAY_SIZE(fixed_link_prop)) == 0) {
                pr_warn_once("%pOF uses deprecated array-style fixed-link binding!\n",
                             np);
                status.link = 1;
                status.duplex = fixed_link_prop[1];
                status.speed  = fixed_link_prop[2];
                status.pause  = fixed_link_prop[3];
                status.asym_pause = fixed_link_prop[4];
                goto register_phy;
        }

        return -ENODEV;

register_phy:
        return PTR_ERR_OR_ZERO(fixed_phy_register(&status, np));
}
EXPORT_SYMBOL(of_phy_register_fixed_link);

void of_phy_deregister_fixed_link(struct device_node *np)
{
        struct phy_device *phydev;

        phydev = of_phy_find_device(np);
        if (!phydev)
                return;

        fixed_phy_unregister(phydev);

        put_device(&phydev->mdio.dev);  /* of_phy_find_device() */
}
EXPORT_SYMBOL(of_phy_deregister_fixed_link);