/* 10G controller driver for Samsung SoCs
 *
 * Copyright (C) 2013 Samsung Electronics Co., Ltd.
 *              http://www.samsung.com
 *
 * Author: Siva Reddy Kallam <siva.kallam@samsung.com>
 *
 * 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.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/io.h>
#include <linux/mii.h>
#include <linux/netdevice.h>
#include <linux/platform_device.h>
#include <linux/phy.h>
#include <linux/slab.h>
#include <linux/sxgbe_platform.h>

#include "sxgbe_common.h"
#include "sxgbe_reg.h"

#define SXGBE_SMA_WRITE_CMD     0x01 /* write command */
#define SXGBE_SMA_PREAD_CMD     0x02 /* post read  increament address */
#define SXGBE_SMA_READ_CMD      0x03 /* read command */
#define SXGBE_SMA_SKIP_ADDRFRM  0x00040000 /* skip the address frame */
#define SXGBE_MII_BUSY          0x00400000 /* mii busy */

static int sxgbe_mdio_busy_wait(void __iomem *ioaddr, unsigned int mii_data)
{
        unsigned long fin_time = jiffies + 3 * HZ; /* 3 seconds */

        while (!time_after(jiffies, fin_time)) {
                if (!(readl(ioaddr + mii_data) & SXGBE_MII_BUSY))
                        return 0;
                cpu_relax();
        }

        return -EBUSY;
}

static void sxgbe_mdio_ctrl_data(struct sxgbe_priv_data *sp, u32 cmd,
                                 u16 phydata)
{
        u32 reg = phydata;

        reg |= (cmd << 16) | SXGBE_SMA_SKIP_ADDRFRM |
               ((sp->clk_csr & 0x7) << 19) | SXGBE_MII_BUSY;
        writel(reg, sp->ioaddr + sp->hw->mii.data);
}

static void sxgbe_mdio_c45(struct sxgbe_priv_data *sp, u32 cmd, int phyaddr,
                           int phyreg, u16 phydata)
{
        u32 reg;

        /* set mdio address register */
        reg = ((phyreg >> 16) & 0x1f) << 21;
        reg |= (phyaddr << 16) | (phyreg & 0xffff);
        writel(reg, sp->ioaddr + sp->hw->mii.addr);

        sxgbe_mdio_ctrl_data(sp, cmd, phydata);
}

static void sxgbe_mdio_c22(struct sxgbe_priv_data *sp, u32 cmd, int phyaddr,
                           int phyreg, u16 phydata)
{
        u32 reg;

        writel(1 << phyaddr, sp->ioaddr + SXGBE_MDIO_CLAUSE22_PORT_REG);

        /* set mdio address register */
        reg = (phyaddr << 16) | (phyreg & 0x1f);
        writel(reg, sp->ioaddr + sp->hw->mii.addr);

        sxgbe_mdio_ctrl_data(sp, cmd, phydata);
}

static int sxgbe_mdio_access(struct sxgbe_priv_data *sp, u32 cmd, int phyaddr,
                             int phyreg, u16 phydata)
{
        const struct mii_regs *mii = &sp->hw->mii;
        int rc;

        rc = sxgbe_mdio_busy_wait(sp->ioaddr, mii->data);
        if (rc < 0)
                return rc;

        if (phyreg & MII_ADDR_C45) {
                sxgbe_mdio_c45(sp, cmd, phyaddr, phyreg, phydata);
        } else {
                 /* Ports 0-3 only support C22. */
                if (phyaddr >= 4)
                        return -ENODEV;

                sxgbe_mdio_c22(sp, cmd, phyaddr, phyreg, phydata);
        }

        return sxgbe_mdio_busy_wait(sp->ioaddr, mii->data);
}

/**
 * sxgbe_mdio_read
 * @bus: points to the mii_bus structure
 * @phyaddr: address of phy port
 * @phyreg: address of register with in phy register
 * Description: this function used for C45 and C22 MDIO Read
 */
static int sxgbe_mdio_read(struct mii_bus *bus, int phyaddr, int phyreg)
{
        struct net_device *ndev = bus->priv;
        struct sxgbe_priv_data *priv = netdev_priv(ndev);
        int rc;

        rc = sxgbe_mdio_access(priv, SXGBE_SMA_READ_CMD, phyaddr, phyreg, 0);
        if (rc < 0)
                return rc;

        return readl(priv->ioaddr + priv->hw->mii.data) & 0xffff;
}

/**
 * sxgbe_mdio_write
 * @bus: points to the mii_bus structure
 * @phyaddr: address of phy port
 * @phyreg: address of phy registers
 * @phydata: data to be written into phy register
 * Description: this function is used for C45 and C22 MDIO write
 */
static int sxgbe_mdio_write(struct mii_bus *bus, int phyaddr, int phyreg,
                             u16 phydata)
{
        struct net_device *ndev = bus->priv;
        struct sxgbe_priv_data *priv = netdev_priv(ndev);

        return sxgbe_mdio_access(priv, SXGBE_SMA_WRITE_CMD, phyaddr, phyreg,
                                 phydata);
}

int sxgbe_mdio_register(struct net_device *ndev)
{
        struct mii_bus *mdio_bus;
        struct sxgbe_priv_data *priv = netdev_priv(ndev);
        struct sxgbe_mdio_bus_data *mdio_data = priv->plat->mdio_bus_data;
        int err, phy_addr;
        int *irqlist;
        bool phy_found = false;
        bool act;

        /* allocate the new mdio bus */
        mdio_bus = mdiobus_alloc();
        if (!mdio_bus) {
                netdev_err(ndev, "%s: mii bus allocation failed\n", __func__);
                return -ENOMEM;
        }

        if (mdio_data->irqs)
                irqlist = mdio_data->irqs;
        else
                irqlist = priv->mii_irq;

        /* assign mii bus fields */
        mdio_bus->name = "sxgbe";
        mdio_bus->read = &sxgbe_mdio_read;
        mdio_bus->write = &sxgbe_mdio_write;
        snprintf(mdio_bus->id, MII_BUS_ID_SIZE, "%s-%x",
                 mdio_bus->name, priv->plat->bus_id);
        mdio_bus->priv = ndev;
        mdio_bus->phy_mask = mdio_data->phy_mask;
        mdio_bus->parent = priv->device;

        /* register with kernel subsystem */
        err = mdiobus_register(mdio_bus);
        if (err != 0) {
                netdev_err(ndev, "mdiobus register failed\n");
                goto mdiobus_err;
        }

        for (phy_addr = 0; phy_addr < PHY_MAX_ADDR; phy_addr++) {
                struct phy_device *phy = mdiobus_get_phy(mdio_bus, phy_addr);

                if (phy) {
                        char irq_num[4];
                        char *irq_str;
                        /* If an IRQ was provided to be assigned after
                         * the bus probe, do it here.
                         */
                        if ((mdio_data->irqs == NULL) &&
                            (mdio_data->probed_phy_irq > 0)) {
                                irqlist[phy_addr] = mdio_data->probed_phy_irq;
                                phy->irq = mdio_data->probed_phy_irq;
                        }

                        /* If we're  going to bind the MAC to this PHY bus,
                         * and no PHY number was provided to the MAC,
                         * use the one probed here.
                         */
                        if (priv->plat->phy_addr == -1)
                                priv->plat->phy_addr = phy_addr;

                        act = (priv->plat->phy_addr == phy_addr);
                        switch (phy->irq) {
                        case PHY_POLL:
                                irq_str = "POLL";
                                break;
                        case PHY_IGNORE_INTERRUPT:
                                irq_str = "IGNORE";
                                break;
                        default:
                                sprintf(irq_num, "%d", phy->irq);
                                irq_str = irq_num;
                                break;
                        }
                        netdev_info(ndev, "PHY ID %08x at %d IRQ %s (%s)%s\n",
                                    phy->phy_id, phy_addr, irq_str,
                                    phydev_name(phy), act ? " active" : "");
                        phy_found = true;
                }
        }

        if (!phy_found) {
                netdev_err(ndev, "PHY not found\n");
                goto phyfound_err;
        }

        priv->mii = mdio_bus;

        return 0;

phyfound_err:
        err = -ENODEV;
        mdiobus_unregister(mdio_bus);
mdiobus_err:
        mdiobus_free(mdio_bus);
        return err;
}

int sxgbe_mdio_unregister(struct net_device *ndev)
{
        struct sxgbe_priv_data *priv = netdev_priv(ndev);

        if (!priv->mii)
                return 0;

        mdiobus_unregister(priv->mii);
        priv->mii->priv = NULL;
        mdiobus_free(priv->mii);
        priv->mii = NULL;

        return 0;
}