/*
 * Freescale PowerQUICC Ethernet Driver -- MIIM bus implementation
 * Provides Bus interface for MIIM regs
 *
 * Author: Andy Fleming <afleming@freescale.com>
 * Modifier: Sandeep Gopalpet <sandeep.kumar@freescale.com>
 *
 * Copyright 2002-2004, 2008-2009 Freescale Semiconductor, Inc.
 *
 * Based on gianfar_mii.c and ucc_geth_mii.c (Li Yang, Kim Phillips)
 *
 * This program is free software; you can redistribute  it and/or modify it
 * under  the terms of  the GNU General  Public License as published by the
 * Free Software Foundation;  either version 2 of the  License, or (at your
 * option) any later version.
 *
 */

#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/unistd.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/spinlock.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/crc32.h>
#include <linux/mii.h>
#include <linux/phy.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_mdio.h>
#include <linux/of_platform.h>

#include <asm/io.h>
#include <asm/irq.h>
#include <asm/uaccess.h>
#include <asm/ucc.h>

#include "gianfar.h"
#include "fsl_pq_mdio.h"

struct fsl_pq_mdio_priv {
        void __iomem *map;
        struct fsl_pq_mdio __iomem *regs;
};

/*
 * Write value to the PHY at mii_id at register regnum,
 * on the bus attached to the local interface, which may be different from the
 * generic mdio bus (tied to a single interface), waiting until the write is
 * done before returning. This is helpful in programming interfaces like
 * the TBI which control interfaces like onchip SERDES and are always tied to
 * the local mdio pins, which may not be the same as system mdio bus, used for
 * controlling the external PHYs, for example.
 */
int fsl_pq_local_mdio_write(struct fsl_pq_mdio __iomem *regs, int mii_id,
                int regnum, u16 value)
{
        /* Set the PHY address and the register address we want to write */
        out_be32(&regs->miimadd, (mii_id << 8) | regnum);

        /* Write out the value we want */
        out_be32(&regs->miimcon, value);

        /* Wait for the transaction to finish */
        while (in_be32(&regs->miimind) & MIIMIND_BUSY)
                cpu_relax();

        return 0;
}

/*
 * Read the bus for PHY at addr mii_id, register regnum, and
 * return the value.  Clears miimcom first.  All PHY operation
 * done on the bus attached to the local interface,
 * which may be different from the generic mdio bus
 * This is helpful in programming interfaces like
 * the TBI which, in turn, control interfaces like onchip SERDES
 * and are always tied to the local mdio pins, which may not be the
 * same as system mdio bus, used for controlling the external PHYs, for eg.
 */
int fsl_pq_local_mdio_read(struct fsl_pq_mdio __iomem *regs,
                int mii_id, int regnum)
{
        u16 value;

        /* Set the PHY address and the register address we want to read */
        out_be32(&regs->miimadd, (mii_id << 8) | regnum);

        /* Clear miimcom, and then initiate a read */
        out_be32(&regs->miimcom, 0);
        out_be32(&regs->miimcom, MII_READ_COMMAND);

        /* Wait for the transaction to finish */
        while (in_be32(&regs->miimind) & (MIIMIND_NOTVALID | MIIMIND_BUSY))
                cpu_relax();

        /* Grab the value of the register from miimstat */
        value = in_be32(&regs->miimstat);

        return value;
}

static struct fsl_pq_mdio __iomem *fsl_pq_mdio_get_regs(struct mii_bus *bus)
{
        struct fsl_pq_mdio_priv *priv = bus->priv;

        return priv->regs;
}

/*
 * Write value to the PHY at mii_id at register regnum,
 * on the bus, waiting until the write is done before returning.
 */
int fsl_pq_mdio_write(struct mii_bus *bus, int mii_id, int regnum, u16 value)
{
        struct fsl_pq_mdio __iomem *regs = fsl_pq_mdio_get_regs(bus);

        /* Write to the local MII regs */
        return fsl_pq_local_mdio_write(regs, mii_id, regnum, value);
}

/*
 * Read the bus for PHY at addr mii_id, register regnum, and
 * return the value.  Clears miimcom first.
 */
int fsl_pq_mdio_read(struct mii_bus *bus, int mii_id, int regnum)
{
        struct fsl_pq_mdio __iomem *regs = fsl_pq_mdio_get_regs(bus);

        /* Read the local MII regs */
        return fsl_pq_local_mdio_read(regs, mii_id, regnum);
}

/* Reset the MIIM registers, and wait for the bus to free */
static int fsl_pq_mdio_reset(struct mii_bus *bus)
{
        struct fsl_pq_mdio __iomem *regs = fsl_pq_mdio_get_regs(bus);
        int timeout = PHY_INIT_TIMEOUT;

        mutex_lock(&bus->mdio_lock);

        /* Reset the management interface */
        out_be32(&regs->miimcfg, MIIMCFG_RESET);

        /* Setup the MII Mgmt clock speed */
        out_be32(&regs->miimcfg, MIIMCFG_INIT_VALUE);

        /* Wait until the bus is free */
        while ((in_be32(&regs->miimind) & MIIMIND_BUSY) && timeout--)
                cpu_relax();

        mutex_unlock(&bus->mdio_lock);

        if (timeout < 0) {
                printk(KERN_ERR "%s: The MII Bus is stuck!\n",
                                bus->name);
                return -EBUSY;
        }

        return 0;
}

void fsl_pq_mdio_bus_name(char *name, struct device_node *np)
{
        const u32 *addr;
        u64 taddr = OF_BAD_ADDR;

        addr = of_get_address(np, 0, NULL, NULL);
        if (addr)
                taddr = of_translate_address(np, addr);

        snprintf(name, MII_BUS_ID_SIZE, "%s@%llx", np->name,
                (unsigned long long)taddr);
}
EXPORT_SYMBOL_GPL(fsl_pq_mdio_bus_name);

/* Scan the bus in reverse, looking for an empty spot */
static int fsl_pq_mdio_find_free(struct mii_bus *new_bus)
{
        int i;

        for (i = PHY_MAX_ADDR; i > 0; i--) {
                u32 phy_id;

                if (get_phy_id(new_bus, i, &phy_id))
                        return -1;

                if (phy_id == 0xffffffff)
                        break;
        }

        return i;
}


#if defined(CONFIG_GIANFAR) || defined(CONFIG_GIANFAR_MODULE)
static u32 __iomem *get_gfar_tbipa(struct fsl_pq_mdio __iomem *regs, struct device_node *np)
{
        struct gfar __iomem *enet_regs;

        /*
         * This is mildly evil, but so is our hardware for doing this.
         * Also, we have to cast back to struct gfar because of
         * definition weirdness done in gianfar.h.
         */
        if(of_device_is_compatible(np, "fsl,gianfar-mdio") ||
                of_device_is_compatible(np, "fsl,gianfar-tbi") ||
                of_device_is_compatible(np, "gianfar")) {
                enet_regs = (struct gfar __iomem *)regs;
                return &enet_regs->tbipa;
        } else if (of_device_is_compatible(np, "fsl,etsec2-mdio") ||
                        of_device_is_compatible(np, "fsl,etsec2-tbi")) {
                return of_iomap(np, 1);
        } else
                return NULL;
}
#endif


#if defined(CONFIG_UCC_GETH) || defined(CONFIG_UCC_GETH_MODULE)
static int get_ucc_id_for_range(u64 start, u64 end, u32 *ucc_id)
{
        struct device_node *np = NULL;
        int err = 0;

        for_each_compatible_node(np, NULL, "ucc_geth") {
                struct resource tempres;

                err = of_address_to_resource(np, 0, &tempres);
                if (err)
                        continue;

                /* if our mdio regs fall within this UCC regs range */
                if ((start >= tempres.start) && (end <= tempres.end)) {
                        /* Find the id of the UCC */
                        const u32 *id;

                        id = of_get_property(np, "cell-index", NULL);
                        if (!id) {
                                id = of_get_property(np, "device-id", NULL);
                                if (!id)
                                        continue;
                        }

                        *ucc_id = *id;

                        return 0;
                }
        }

        if (err)
                return err;
        else
                return -EINVAL;
}
#endif


static int fsl_pq_mdio_probe(struct platform_device *ofdev)
{
        struct device_node *np = ofdev->dev.of_node;
        struct device_node *tbi;
        struct fsl_pq_mdio_priv *priv;
        struct fsl_pq_mdio __iomem *regs = NULL;
        void __iomem *map;
        u32 __iomem *tbipa;
        struct mii_bus *new_bus;
        int tbiaddr = -1;
        const u32 *addrp;
        u64 addr = 0, size = 0;
        int err;

        priv = kzalloc(sizeof(*priv), GFP_KERNEL);
        if (!priv)
                return -ENOMEM;

        new_bus = mdiobus_alloc();
        if (!new_bus) {
                err = -ENOMEM;
                goto err_free_priv;
        }

        new_bus->name = "Freescale PowerQUICC MII Bus",
        new_bus->read = &fsl_pq_mdio_read,
        new_bus->write = &fsl_pq_mdio_write,
        new_bus->reset = &fsl_pq_mdio_reset,
        new_bus->priv = priv;
        fsl_pq_mdio_bus_name(new_bus->id, np);

        addrp = of_get_address(np, 0, &size, NULL);
        if (!addrp) {
                err = -EINVAL;
                goto err_free_bus;
        }

        /* Set the PHY base address */
        addr = of_translate_address(np, addrp);
        if (addr == OF_BAD_ADDR) {
                err = -EINVAL;
                goto err_free_bus;
        }

        map = ioremap(addr, size);
        if (!map) {
                err = -ENOMEM;
                goto err_free_bus;
        }
        priv->map = map;

        if (of_device_is_compatible(np, "fsl,gianfar-mdio") ||
                        of_device_is_compatible(np, "fsl,gianfar-tbi") ||
                        of_device_is_compatible(np, "fsl,ucc-mdio") ||
                        of_device_is_compatible(np, "ucc_geth_phy"))
                map -= offsetof(struct fsl_pq_mdio, miimcfg);
        regs = map;
        priv->regs = regs;

        new_bus->irq = kcalloc(PHY_MAX_ADDR, sizeof(int), GFP_KERNEL);

        if (NULL == new_bus->irq) {
                err = -ENOMEM;
                goto err_unmap_regs;
        }

        new_bus->parent = &ofdev->dev;
        dev_set_drvdata(&ofdev->dev, new_bus);

        if (of_device_is_compatible(np, "fsl,gianfar-mdio") ||
                        of_device_is_compatible(np, "fsl,gianfar-tbi") ||
                        of_device_is_compatible(np, "fsl,etsec2-mdio") ||
                        of_device_is_compatible(np, "fsl,etsec2-tbi") ||
                        of_device_is_compatible(np, "gianfar")) {
#if defined(CONFIG_GIANFAR) || defined(CONFIG_GIANFAR_MODULE)
                tbipa = get_gfar_tbipa(regs, np);
                if (!tbipa) {
                        err = -EINVAL;
                        goto err_free_irqs;
                }
#else
                err = -ENODEV;
                goto err_free_irqs;
#endif
        } else if (of_device_is_compatible(np, "fsl,ucc-mdio") ||
                        of_device_is_compatible(np, "ucc_geth_phy")) {
#if defined(CONFIG_UCC_GETH) || defined(CONFIG_UCC_GETH_MODULE)
                u32 id;
                static u32 mii_mng_master;

                tbipa = &regs->utbipar;

                if ((err = get_ucc_id_for_range(addr, addr + size, &id)))
                        goto err_free_irqs;

                if (!mii_mng_master) {
                        mii_mng_master = id;
                        ucc_set_qe_mux_mii_mng(id - 1);
                }
#else
                err = -ENODEV;
                goto err_free_irqs;
#endif
        } else {
                err = -ENODEV;
                goto err_free_irqs;
        }

        for_each_child_of_node(np, tbi) {
                if (!strncmp(tbi->type, "tbi-phy", 8))
                        break;
        }

        if (tbi) {
                const u32 *prop = of_get_property(tbi, "reg", NULL);

                if (prop)
                        tbiaddr = *prop;
        }

        if (tbiaddr == -1) {
                out_be32(tbipa, 0);

                tbiaddr = fsl_pq_mdio_find_free(new_bus);
        }

        /*
         * We define TBIPA at 0 to be illegal, opting to fail for boards that
         * have PHYs at 1-31, rather than change tbipa and rescan.
         */
        if (tbiaddr == 0) {
                err = -EBUSY;

                goto err_free_irqs;
        }

        out_be32(tbipa, tbiaddr);

        err = of_mdiobus_register(new_bus, np);
        if (err) {
                printk (KERN_ERR "%s: Cannot register as MDIO bus\n",
                                new_bus->name);
                goto err_free_irqs;
        }

        return 0;

err_free_irqs:
        kfree(new_bus->irq);
err_unmap_regs:
        iounmap(priv->map);
err_free_bus:
        kfree(new_bus);
err_free_priv:
        kfree(priv);
        return err;
}


static int fsl_pq_mdio_remove(struct platform_device *ofdev)
{
        struct device *device = &ofdev->dev;
        struct mii_bus *bus = dev_get_drvdata(device);
        struct fsl_pq_mdio_priv *priv = bus->priv;

        mdiobus_unregister(bus);

        dev_set_drvdata(device, NULL);

        iounmap(priv->map);
        bus->priv = NULL;
        mdiobus_free(bus);
        kfree(priv);

        return 0;
}

static struct of_device_id fsl_pq_mdio_match[] = {
        {
                .type = "mdio",
                .compatible = "ucc_geth_phy",
        },
        {
                .type = "mdio",
                .compatible = "gianfar",
        },
        {
                .compatible = "fsl,ucc-mdio",
        },
        {
                .compatible = "fsl,gianfar-tbi",
        },
        {
                .compatible = "fsl,gianfar-mdio",
        },
        {
                .compatible = "fsl,etsec2-tbi",
        },
        {
                .compatible = "fsl,etsec2-mdio",
        },
        {},
};
MODULE_DEVICE_TABLE(of, fsl_pq_mdio_match);

static struct platform_driver fsl_pq_mdio_driver = {
        .driver = {
                .name = "fsl-pq_mdio",
                .owner = THIS_MODULE,
                .of_match_table = fsl_pq_mdio_match,
        },
        .probe = fsl_pq_mdio_probe,
        .remove = fsl_pq_mdio_remove,
};

int __init fsl_pq_mdio_init(void)
{
        return platform_driver_register(&fsl_pq_mdio_driver);
}
module_init(fsl_pq_mdio_init);

void fsl_pq_mdio_exit(void)
{
        platform_driver_unregister(&fsl_pq_mdio_driver);
}
module_exit(fsl_pq_mdio_exit);
MODULE_LICENSE("GPL");