/*
 * Broadcom GENET MDIO routines
 *
 * Copyright (c) 2014 Broadcom Corporation
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */


#include <linux/types.h>
#include <linux/delay.h>
#include <linux/wait.h>
#include <linux/mii.h>
#include <linux/ethtool.h>
#include <linux/bitops.h>
#include <linux/netdevice.h>
#include <linux/platform_device.h>
#include <linux/phy.h>
#include <linux/phy_fixed.h>
#include <linux/brcmphy.h>
#include <linux/of.h>
#include <linux/of_net.h>
#include <linux/of_mdio.h>
#include <linux/platform_data/bcmgenet.h>

#include "bcmgenet.h"

/* read a value from the MII */
static int bcmgenet_mii_read(struct mii_bus *bus, int phy_id, int location)
{
        int ret;
        struct net_device *dev = bus->priv;
        struct bcmgenet_priv *priv = netdev_priv(dev);
        u32 reg;

        bcmgenet_umac_writel(priv, (MDIO_RD | (phy_id << MDIO_PMD_SHIFT) |
                             (location << MDIO_REG_SHIFT)), UMAC_MDIO_CMD);
        /* Start MDIO transaction*/
        reg = bcmgenet_umac_readl(priv, UMAC_MDIO_CMD);
        reg |= MDIO_START_BUSY;
        bcmgenet_umac_writel(priv, reg, UMAC_MDIO_CMD);
        wait_event_timeout(priv->wq,
                           !(bcmgenet_umac_readl(priv, UMAC_MDIO_CMD)
                           & MDIO_START_BUSY),
                           HZ / 100);
        ret = bcmgenet_umac_readl(priv, UMAC_MDIO_CMD);

        /* Some broken devices are known not to release the line during
         * turn-around, e.g: Broadcom BCM53125 external switches, so check for
         * that condition here and ignore the MDIO controller read failure
         * indication.
         */
        if (!(bus->phy_ignore_ta_mask & 1 << phy_id) && (ret & MDIO_READ_FAIL))
                return -EIO;

        return ret & 0xffff;
}

/* write a value to the MII */
static int bcmgenet_mii_write(struct mii_bus *bus, int phy_id,
                              int location, u16 val)
{
        struct net_device *dev = bus->priv;
        struct bcmgenet_priv *priv = netdev_priv(dev);
        u32 reg;

        bcmgenet_umac_writel(priv, (MDIO_WR | (phy_id << MDIO_PMD_SHIFT) |
                             (location << MDIO_REG_SHIFT) | (0xffff & val)),
                             UMAC_MDIO_CMD);
        reg = bcmgenet_umac_readl(priv, UMAC_MDIO_CMD);
        reg |= MDIO_START_BUSY;
        bcmgenet_umac_writel(priv, reg, UMAC_MDIO_CMD);
        wait_event_timeout(priv->wq,
                           !(bcmgenet_umac_readl(priv, UMAC_MDIO_CMD) &
                           MDIO_START_BUSY),
                           HZ / 100);

        return 0;
}

/* setup netdev link state when PHY link status change and
 * update UMAC and RGMII block when link up
 */
void bcmgenet_mii_setup(struct net_device *dev)
{
        struct bcmgenet_priv *priv = netdev_priv(dev);
        struct phy_device *phydev = priv->phydev;
        u32 reg, cmd_bits = 0;
        bool status_changed = false;

        if (priv->old_link != phydev->link) {
                status_changed = true;
                priv->old_link = phydev->link;
        }

        if (phydev->link) {
                /* check speed/duplex/pause changes */
                if (priv->old_speed != phydev->speed) {
                        status_changed = true;
                        priv->old_speed = phydev->speed;
                }

                if (priv->old_duplex != phydev->duplex) {
                        status_changed = true;
                        priv->old_duplex = phydev->duplex;
                }

                if (priv->old_pause != phydev->pause) {
                        status_changed = true;
                        priv->old_pause = phydev->pause;
                }

                /* done if nothing has changed */
                if (!status_changed)
                        return;

                /* speed */
                if (phydev->speed == SPEED_1000)
                        cmd_bits = UMAC_SPEED_1000;
                else if (phydev->speed == SPEED_100)
                        cmd_bits = UMAC_SPEED_100;
                else
                        cmd_bits = UMAC_SPEED_10;
                cmd_bits <<= CMD_SPEED_SHIFT;

                /* duplex */
                if (phydev->duplex != DUPLEX_FULL)
                        cmd_bits |= CMD_HD_EN;

                /* pause capability */
                if (!phydev->pause)
                        cmd_bits |= CMD_RX_PAUSE_IGNORE | CMD_TX_PAUSE_IGNORE;

                /*
                 * Program UMAC and RGMII block based on established
                 * link speed, duplex, and pause. The speed set in
                 * umac->cmd tell RGMII block which clock to use for
                 * transmit -- 25MHz(100Mbps) or 125MHz(1Gbps).
                 * Receive clock is provided by the PHY.
                 */
                reg = bcmgenet_ext_readl(priv, EXT_RGMII_OOB_CTRL);
                reg &= ~OOB_DISABLE;
                reg |= RGMII_LINK;
                bcmgenet_ext_writel(priv, reg, EXT_RGMII_OOB_CTRL);

                reg = bcmgenet_umac_readl(priv, UMAC_CMD);
                reg &= ~((CMD_SPEED_MASK << CMD_SPEED_SHIFT) |
                               CMD_HD_EN |
                               CMD_RX_PAUSE_IGNORE | CMD_TX_PAUSE_IGNORE);
                reg |= cmd_bits;
                bcmgenet_umac_writel(priv, reg, UMAC_CMD);
        } else {
                /* done if nothing has changed */
                if (!status_changed)
                        return;

                /* needed for MoCA fixed PHY to reflect correct link status */
                netif_carrier_off(dev);
        }

        phy_print_status(phydev);
}


static int bcmgenet_fixed_phy_link_update(struct net_device *dev,
                                          struct fixed_phy_status *status)
{
        if (dev && dev->phydev && status)
                status->link = dev->phydev->link;

        return 0;
}

/* Perform a voluntary PHY software reset, since the EPHY is very finicky about
 * not doing it and will start corrupting packets
 */
void bcmgenet_mii_reset(struct net_device *dev)
{
        struct bcmgenet_priv *priv = netdev_priv(dev);

        if (GENET_IS_V4(priv))
                return;

        if (priv->phydev) {
                phy_init_hw(priv->phydev);
                phy_start_aneg(priv->phydev);
        }
}

void bcmgenet_phy_power_set(struct net_device *dev, bool enable)
{
        struct bcmgenet_priv *priv = netdev_priv(dev);
        u32 reg = 0;

        /* EXT_GPHY_CTRL is only valid for GENETv4 and onward */
        if (!GENET_IS_V4(priv))
                return;

        reg = bcmgenet_ext_readl(priv, EXT_GPHY_CTRL);
        if (enable) {
                reg &= ~EXT_CK25_DIS;
                bcmgenet_ext_writel(priv, reg, EXT_GPHY_CTRL);
                mdelay(1);

                reg &= ~(EXT_CFG_IDDQ_BIAS | EXT_CFG_PWR_DOWN);
                reg |= EXT_GPHY_RESET;
                bcmgenet_ext_writel(priv, reg, EXT_GPHY_CTRL);
                mdelay(1);

                reg &= ~EXT_GPHY_RESET;
        } else {
                reg |= EXT_CFG_IDDQ_BIAS | EXT_CFG_PWR_DOWN | EXT_GPHY_RESET;
                bcmgenet_ext_writel(priv, reg, EXT_GPHY_CTRL);
                mdelay(1);
                reg |= EXT_CK25_DIS;
        }
        bcmgenet_ext_writel(priv, reg, EXT_GPHY_CTRL);
        udelay(60);
}

static void bcmgenet_internal_phy_setup(struct net_device *dev)
{
        struct bcmgenet_priv *priv = netdev_priv(dev);
        u32 reg;

        /* Power up PHY */
        bcmgenet_phy_power_set(dev, true);
        /* enable APD */
        reg = bcmgenet_ext_readl(priv, EXT_EXT_PWR_MGMT);
        reg |= EXT_PWR_DN_EN_LD;
        bcmgenet_ext_writel(priv, reg, EXT_EXT_PWR_MGMT);
        bcmgenet_mii_reset(dev);
}

static void bcmgenet_moca_phy_setup(struct bcmgenet_priv *priv)
{
        u32 reg;

        /* Speed settings are set in bcmgenet_mii_setup() */
        reg = bcmgenet_sys_readl(priv, SYS_PORT_CTRL);
        reg |= LED_ACT_SOURCE_MAC;
        bcmgenet_sys_writel(priv, reg, SYS_PORT_CTRL);

        if (priv->hw_params->flags & GENET_HAS_MOCA_LINK_DET)
                fixed_phy_set_link_update(priv->phydev,
                                          bcmgenet_fixed_phy_link_update);
}

int bcmgenet_mii_config(struct net_device *dev)
{
        struct bcmgenet_priv *priv = netdev_priv(dev);
        struct phy_device *phydev = priv->phydev;
        struct device *kdev = &priv->pdev->dev;
        const char *phy_name = NULL;
        u32 id_mode_dis = 0;
        u32 port_ctrl;
        u32 reg;

        priv->ext_phy = !priv->internal_phy &&
                        (priv->phy_interface != PHY_INTERFACE_MODE_MOCA);

        if (priv->internal_phy)
                priv->phy_interface = PHY_INTERFACE_MODE_NA;

        switch (priv->phy_interface) {
        case PHY_INTERFACE_MODE_NA:
        case PHY_INTERFACE_MODE_MOCA:
                /* Irrespective of the actually configured PHY speed (100 or
                 * 1000) GENETv4 only has an internal GPHY so we will just end
                 * up masking the Gigabit features from what we support, not
                 * switching to the EPHY
                 */
                if (GENET_IS_V4(priv))
                        port_ctrl = PORT_MODE_INT_GPHY;
                else
                        port_ctrl = PORT_MODE_INT_EPHY;

                bcmgenet_sys_writel(priv, port_ctrl, SYS_PORT_CTRL);

                if (priv->internal_phy) {
                        phy_name = "internal PHY";
                        bcmgenet_internal_phy_setup(dev);
                } else if (priv->phy_interface == PHY_INTERFACE_MODE_MOCA) {
                        phy_name = "MoCA";
                        bcmgenet_moca_phy_setup(priv);
                }
                break;

        case PHY_INTERFACE_MODE_MII:
                phy_name = "external MII";
                phydev->supported &= PHY_BASIC_FEATURES;
                bcmgenet_sys_writel(priv,
                                    PORT_MODE_EXT_EPHY, SYS_PORT_CTRL);
                break;

        case PHY_INTERFACE_MODE_REVMII:
                phy_name = "external RvMII";
                /* of_mdiobus_register took care of reading the 'max-speed'
                 * PHY property for us, effectively limiting the PHY supported
                 * capabilities, use that knowledge to also configure the
                 * Reverse MII interface correctly.
                 */
                if ((priv->phydev->supported & PHY_BASIC_FEATURES) ==
                                PHY_BASIC_FEATURES)
                        port_ctrl = PORT_MODE_EXT_RVMII_25;
                else
                        port_ctrl = PORT_MODE_EXT_RVMII_50;
                bcmgenet_sys_writel(priv, port_ctrl, SYS_PORT_CTRL);
                break;

        case PHY_INTERFACE_MODE_RGMII:
                /* RGMII_NO_ID: TXC transitions at the same time as TXD
                 *              (requires PCB or receiver-side delay)
                 * RGMII:       Add 2ns delay on TXC (90 degree shift)
                 *
                 * ID is implicitly disabled for 100Mbps (RG)MII operation.
                 */
                id_mode_dis = BIT(16);
                /* fall through */
        case PHY_INTERFACE_MODE_RGMII_TXID:
                if (id_mode_dis)
                        phy_name = "external RGMII (no delay)";
                else
                        phy_name = "external RGMII (TX delay)";
                bcmgenet_sys_writel(priv,
                                    PORT_MODE_EXT_GPHY, SYS_PORT_CTRL);
                break;
        default:
                dev_err(kdev, "unknown phy mode: %d\n", priv->phy_interface);
                return -EINVAL;
        }

        /* This is an external PHY (xMII), so we need to enable the RGMII
         * block for the interface to work
         */
        if (priv->ext_phy) {
                reg = bcmgenet_ext_readl(priv, EXT_RGMII_OOB_CTRL);
                reg |= RGMII_MODE_EN | id_mode_dis;
                bcmgenet_ext_writel(priv, reg, EXT_RGMII_OOB_CTRL);
        }

        dev_info_once(kdev, "configuring instance for %s\n", phy_name);

        return 0;
}

int bcmgenet_mii_probe(struct net_device *dev)
{
        struct bcmgenet_priv *priv = netdev_priv(dev);
        struct device_node *dn = priv->pdev->dev.of_node;
        struct phy_device *phydev;
        u32 phy_flags;
        int ret;

        /* Communicate the integrated PHY revision */
        phy_flags = priv->gphy_rev;

        /* Initialize link state variables that bcmgenet_mii_setup() uses */
        priv->old_link = -1;
        priv->old_speed = -1;
        priv->old_duplex = -1;
        priv->old_pause = -1;

        if (dn) {
                phydev = of_phy_connect(dev, priv->phy_dn, bcmgenet_mii_setup,
                                        phy_flags, priv->phy_interface);
                if (!phydev) {
                        pr_err("could not attach to PHY\n");
                        return -ENODEV;
                }
        } else {
                phydev = priv->phydev;
                phydev->dev_flags = phy_flags;

                ret = phy_connect_direct(dev, phydev, bcmgenet_mii_setup,
                                         priv->phy_interface);
                if (ret) {
                        pr_err("could not attach to PHY\n");
                        return -ENODEV;
                }
        }

        priv->phydev = phydev;

        /* Configure port multiplexer based on what the probed PHY device since
         * reading the 'max-speed' property determines the maximum supported
         * PHY speed which is needed for bcmgenet_mii_config() to configure
         * things appropriately.
         */
        ret = bcmgenet_mii_config(dev);
        if (ret) {
                phy_disconnect(priv->phydev);
                return ret;
        }

        phydev->advertising = phydev->supported;

        /* The internal PHY has its link interrupts routed to the
         * Ethernet MAC ISRs
         */
        if (priv->internal_phy)
                priv->phydev->irq = PHY_IGNORE_INTERRUPT;

        return 0;
}

/* Workaround for integrated BCM7xxx Gigabit PHYs which have a problem with
 * their internal MDIO management controller making them fail to successfully
 * be read from or written to for the first transaction.  We insert a dummy
 * BMSR read here to make sure that phy_get_device() and get_phy_id() can
 * correctly read the PHY MII_PHYSID1/2 registers and successfully register a
 * PHY device for this peripheral.
 *
 * Once the PHY driver is registered, we can workaround subsequent reads from
 * there (e.g: during system-wide power management).
 *
 * bus->reset is invoked before mdiobus_scan during mdiobus_register and is
 * therefore the right location to stick that workaround. Since we do not want
 * to read from non-existing PHYs, we either use bus->phy_mask or do a manual
 * Device Tree scan to limit the search area.
 */
static int bcmgenet_mii_bus_reset(struct mii_bus *bus)
{
        struct net_device *dev = bus->priv;
        struct bcmgenet_priv *priv = netdev_priv(dev);
        struct device_node *np = priv->mdio_dn;
        struct device_node *child = NULL;
        u32 read_mask = 0;
        int addr = 0;

        if (!np) {
                read_mask = 1 << priv->phy_addr;
        } else {
                for_each_available_child_of_node(np, child) {
                        addr = of_mdio_parse_addr(&dev->dev, child);
                        if (addr < 0)
                                continue;

                        read_mask |= 1 << addr;
                }
        }

        for (addr = 0; addr < PHY_MAX_ADDR; addr++) {
                if (read_mask & 1 << addr) {
                        dev_dbg(&dev->dev, "Workaround for PHY @ %d\n", addr);
                        mdiobus_read(bus, addr, MII_BMSR);
                }
        }

        return 0;
}

static int bcmgenet_mii_alloc(struct bcmgenet_priv *priv)
{
        struct mii_bus *bus;

        if (priv->mii_bus)
                return 0;

        priv->mii_bus = mdiobus_alloc();
        if (!priv->mii_bus) {
                pr_err("failed to allocate\n");
                return -ENOMEM;
        }

        bus = priv->mii_bus;
        bus->priv = priv->dev;
        bus->name = "bcmgenet MII bus";
        bus->parent = &priv->pdev->dev;
        bus->read = bcmgenet_mii_read;
        bus->write = bcmgenet_mii_write;
        bus->reset = bcmgenet_mii_bus_reset;
        snprintf(bus->id, MII_BUS_ID_SIZE, "%s-%d",
                 priv->pdev->name, priv->pdev->id);

        return 0;
}

static int bcmgenet_mii_of_init(struct bcmgenet_priv *priv)
{
        struct device_node *dn = priv->pdev->dev.of_node;
        struct device *kdev = &priv->pdev->dev;
        const char *phy_mode_str = NULL;
        struct phy_device *phydev = NULL;
        char *compat;
        int phy_mode;
        int ret;

        compat = kasprintf(GFP_KERNEL, "brcm,genet-mdio-v%d", priv->version);
        if (!compat)
                return -ENOMEM;

        priv->mdio_dn = of_find_compatible_node(dn, NULL, compat);
        kfree(compat);
        if (!priv->mdio_dn) {
                dev_err(kdev, "unable to find MDIO bus node\n");
                return -ENODEV;
        }

        ret = of_mdiobus_register(priv->mii_bus, priv->mdio_dn);
        if (ret) {
                dev_err(kdev, "failed to register MDIO bus\n");
                return ret;
        }

        /* Fetch the PHY phandle */
        priv->phy_dn = of_parse_phandle(dn, "phy-handle", 0);

        /* In the case of a fixed PHY, the DT node associated
         * to the PHY is the Ethernet MAC DT node.
         */
        if (!priv->phy_dn && of_phy_is_fixed_link(dn)) {
                ret = of_phy_register_fixed_link(dn);
                if (ret)
                        return ret;

                priv->phy_dn = of_node_get(dn);
        }

        /* Get the link mode */
        phy_mode = of_get_phy_mode(dn);
        priv->phy_interface = phy_mode;

        /* We need to specifically look up whether this PHY interface is internal
         * or not *before* we even try to probe the PHY driver over MDIO as we
         * may have shut down the internal PHY for power saving purposes.
         */
        if (phy_mode < 0) {
                ret = of_property_read_string(dn, "phy-mode", &phy_mode_str);
                if (ret < 0) {
                        dev_err(kdev, "invalid PHY mode property\n");
                        return ret;
                }

                priv->phy_interface = PHY_INTERFACE_MODE_NA;
                if (!strcasecmp(phy_mode_str, "internal"))
                        priv->internal_phy = true;
        }

        /* Make sure we initialize MoCA PHYs with a link down */
        if (phy_mode == PHY_INTERFACE_MODE_MOCA) {
                phydev = of_phy_find_device(dn);
                if (phydev) {
                        phydev->link = 0;
                        put_device(&phydev->mdio.dev);
                }
        }

        return 0;
}

static int bcmgenet_mii_pd_init(struct bcmgenet_priv *priv)
{
        struct device *kdev = &priv->pdev->dev;
        struct bcmgenet_platform_data *pd = kdev->platform_data;
        struct mii_bus *mdio = priv->mii_bus;
        struct phy_device *phydev;
        int ret;

        if (pd->phy_interface != PHY_INTERFACE_MODE_MOCA && pd->mdio_enabled) {
                /*
                 * Internal or external PHY with MDIO access
                 */
                if (pd->phy_address >= 0 && pd->phy_address < PHY_MAX_ADDR)
                        mdio->phy_mask = ~(1 << pd->phy_address);
                else
                        mdio->phy_mask = 0;

                ret = mdiobus_register(mdio);
                if (ret) {
                        dev_err(kdev, "failed to register MDIO bus\n");
                        return ret;
                }

                if (pd->phy_address >= 0 && pd->phy_address < PHY_MAX_ADDR)
                        phydev = mdiobus_get_phy(mdio, pd->phy_address);
                else
                        phydev = phy_find_first(mdio);

                if (!phydev) {
                        dev_err(kdev, "failed to register PHY device\n");
                        mdiobus_unregister(mdio);
                        return -ENODEV;
                }
        } else {
                /*
                 * MoCA port or no MDIO access.
                 * Use fixed PHY to represent the link layer.
                 */
                struct fixed_phy_status fphy_status = {
                        .link = 1,
                        .speed = pd->phy_speed,
                        .duplex = pd->phy_duplex,
                        .pause = 0,
                        .asym_pause = 0,
                };

                phydev = fixed_phy_register(PHY_POLL, &fphy_status, -1, NULL);
                if (!phydev || IS_ERR(phydev)) {
                        dev_err(kdev, "failed to register fixed PHY device\n");
                        return -ENODEV;
                }

                /* Make sure we initialize MoCA PHYs with a link down */
                phydev->link = 0;

        }

        priv->phydev = phydev;
        priv->phy_interface = pd->phy_interface;

        return 0;
}

static int bcmgenet_mii_bus_init(struct bcmgenet_priv *priv)
{
        struct device_node *dn = priv->pdev->dev.of_node;

        if (dn)
                return bcmgenet_mii_of_init(priv);
        else
                return bcmgenet_mii_pd_init(priv);
}

int bcmgenet_mii_init(struct net_device *dev)
{
        struct bcmgenet_priv *priv = netdev_priv(dev);
        struct device_node *dn = priv->pdev->dev.of_node;
        int ret;

        ret = bcmgenet_mii_alloc(priv);
        if (ret)
                return ret;

        ret = bcmgenet_mii_bus_init(priv);
        if (ret)
                goto out;

        return 0;

out:
        if (of_phy_is_fixed_link(dn))
                of_phy_deregister_fixed_link(dn);
        of_node_put(priv->phy_dn);
        mdiobus_unregister(priv->mii_bus);
        mdiobus_free(priv->mii_bus);
        return ret;
}

void bcmgenet_mii_exit(struct net_device *dev)
{
        struct bcmgenet_priv *priv = netdev_priv(dev);
        struct device_node *dn = priv->pdev->dev.of_node;

        if (of_phy_is_fixed_link(dn))
                of_phy_deregister_fixed_link(dn);
        of_node_put(priv->phy_dn);
        mdiobus_unregister(priv->mii_bus);
        mdiobus_free(priv->mii_bus);
}