/*
 * OF helpers for the MDIO (Ethernet PHY) API
 *
 * Copyright (c) 2009 Secret Lab Technologies, Ltd.
 *
 * This file is released under the GPLv2
 *
 * 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/kernel.h>
#include <linux/device.h>
#include <linux/netdevice.h>
#include <linux/err.h>
#include <linux/phy.h>
#include <linux/phy_fixed.h>
#include <linux/of.h>
#include <linux/of_gpio.h>
#include <linux/of_irq.h>
#include <linux/of_mdio.h>
#include <linux/of_net.h>
#include <linux/module.h>

#define DEFAULT_GPIO_RESET_DELAY        10      /* in microseconds */

MODULE_AUTHOR("Grant Likely <grant.likely@secretlab.ca>");
MODULE_LICENSE("GPL");

/* 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)
{
        struct property *prop;
        const char *cp;
        unsigned int upper, lower;

        of_property_for_each_string(device, "compatible", prop, cp) {
                if (sscanf(cp, "ethernet-phy-id%4x.%4x", &upper, &lower) == 2) {
                        *phy_id = ((upper & 0xFFFF) << 16) | (lower & 0xFFFF);
                        return 0;
                }
        }
        return -EINVAL;
}

static void of_mdiobus_register_phy(struct mii_bus *mdio,
                                    struct device_node *child, u32 addr)
{
        struct phy_device *phy;
        bool is_c45;
        int rc;
        u32 phy_id;

        is_c45 = of_device_is_compatible(child,
                                         "ethernet-phy-ieee802.3-c45");

        if (!is_c45 && !of_get_phy_id(child, &phy_id))
                phy = phy_device_create(mdio, addr, phy_id, 0, NULL);
        else
                phy = get_phy_device(mdio, addr, is_c45);
        if (IS_ERR(phy))
                return;

        rc = irq_of_parse_and_map(child, 0);
        if (rc > 0) {
                phy->irq = rc;
                mdio->irq[addr] = rc;
        } else {
                phy->irq = mdio->irq[addr];
        }

        if (of_property_read_bool(child, "broken-turn-around"))
                mdio->phy_ignore_ta_mask |= 1 << addr;

        /* Associate the OF node with the device structure so it
         * can be looked up later */
        of_node_get(child);
        phy->mdio.dev.of_node = child;

        /* All data is now stored in the phy struct;
         * register it */
        rc = phy_device_register(phy);
        if (rc) {
                phy_device_free(phy);
                of_node_put(child);
                return;
        }

        dev_dbg(&mdio->dev, "registered phy %s at address %i\n",
                child->name, addr);
}

static void of_mdiobus_register_device(struct mii_bus *mdio,
                                       struct device_node *child, u32 addr)
{
        struct mdio_device *mdiodev;
        int rc;

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

        /* Associate the OF node with the device structure so it
         * can be looked up later.
         */
        of_node_get(child);
        mdiodev->dev.of_node = child;

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

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

/* 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.
 */
static 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
                        "%s: Whitelisted compatible string. Please remove\n",
                        child->full_name);
                return true;
        }

        if (!of_find_property(child, "compatible", NULL))
                return true;

        return false;
}

/**
 * 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.
 *
 * 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 device_node *child;
        bool scanphys = false;
        int addr, rc;

        /* 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;

        mdio->dev.of_node = 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);

        /* Register the MDIO bus */
        rc = mdiobus_register(mdio);
        if (rc)
                return rc;

        /* Loop over the child nodes and register a phy_device for each phy */
        for_each_available_child_of_node(np, child) {
                addr = of_mdio_parse_addr(&mdio->dev, child);
                if (addr < 0) {
                        scanphys = true;
                        continue;
                }

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

        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 */
                if (of_find_property(child, "reg", NULL))
                        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 %s at address %i\n",
                                 child->name, addr);

                        if (of_mdiobus_child_is_phy(child))
                                of_mdiobus_register_phy(mdio, child, addr);
                }
        }

        return 0;
}
EXPORT_SYMBOL(of_mdiobus_register);

/* Helper function for of_phy_find_device */
static int of_phy_match(struct device *dev, void *phy_np)
{
        return dev->of_node == phy_np;
}

/**
 * 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)
{
        struct device *d;
        struct mdio_device *mdiodev;

        if (!phy_np)
                return NULL;

        d = bus_find_device(&mdio_bus_type, NULL, phy_np, of_phy_match);
        if (d) {
                mdiodev = to_mdio_device(d);
                if (mdiodev->flags & MDIO_DEVICE_FLAG_PHY)
                        return to_phy_device(d);
                put_device(d);
        }

        return NULL;
}
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;

        iface = of_get_phy_mode(np);
        if (iface < 0)
                return NULL;

        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_attach - Attach to a PHY without starting the state machine
 * @dev: pointer to net_device claiming the phy
 * @phy_np: Node pointer for the PHY
 * @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_attach(struct net_device *dev,
                                 struct device_node *phy_np, u32 flags,
                                 phy_interface_t iface)
{
        struct phy_device *phy = of_phy_find_device(phy_np);
        int ret;

        if (!phy)
                return NULL;

        ret = phy_attach_direct(dev, phy, flags, iface);

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

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

/*
 * 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 informations 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 len, 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_get_property(np, "fixed-link", &len) &&
            len == (5 * sizeof(__be32)))
                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;
        const __be32 *fixed_link_prop;
        int link_gpio;
        int len, err;
        struct phy_device *phy;
        const char *managed;

        err = of_property_read_string(np, "managed", &managed);
        if (err == 0) {
                if (strcmp(managed, "in-band-status") == 0) {
                        /* status is zeroed, namely its .link member */
                        phy = fixed_phy_register(PHY_POLL, &status, -1, np);
                        return PTR_ERR_OR_ZERO(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");
                link_gpio = of_get_named_gpio_flags(fixed_link_node,
                                                    "link-gpios", 0, NULL);
                of_node_put(fixed_link_node);
                if (link_gpio == -EPROBE_DEFER)
                        return -EPROBE_DEFER;

                phy = fixed_phy_register(PHY_POLL, &status, link_gpio, np);
                return PTR_ERR_OR_ZERO(phy);
        }

        /* Old binding */
        fixed_link_prop = of_get_property(np, "fixed-link", &len);
        if (fixed_link_prop && len == (5 * sizeof(__be32))) {
                status.link = 1;
                status.duplex = be32_to_cpu(fixed_link_prop[1]);
                status.speed = be32_to_cpu(fixed_link_prop[2]);
                status.pause = be32_to_cpu(fixed_link_prop[3]);
                status.asym_pause = be32_to_cpu(fixed_link_prop[4]);
                phy = fixed_phy_register(PHY_POLL, &status, -1, np);
                return PTR_ERR_OR_ZERO(phy);
        }

        return -ENODEV;
}
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() */
        phy_device_free(phydev);        /* fixed_phy_register() */
}
EXPORT_SYMBOL(of_phy_deregister_fixed_link);