// SPDX-License-Identifier: GPL-2.0+
/*
 * drivers/net/phy/lxt.c
 *
 * Driver for Intel LXT PHYs
 *
 * Author: Andy Fleming
 *
 * Copyright (c) 2004 Freescale Semiconductor, Inc.
 */
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/unistd.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/mii.h>
#include <linux/ethtool.h>
#include <linux/phy.h>

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

/* The Level one LXT970 is used by many boards                               */

#define MII_LXT970_IER       17  /* Interrupt Enable Register */

#define MII_LXT970_IER_IEN      0x0002

#define MII_LXT970_ISR       18  /* Interrupt Status Register */

#define MII_LXT970_IRS_MINT  BIT(15)

#define MII_LXT970_CONFIG    19  /* Configuration Register    */

/* ------------------------------------------------------------------------- */
/* The Level one LXT971 is used on some of my custom boards                  */

/* register definitions for the 971 */
#define MII_LXT971_IER          18  /* Interrupt Enable Register */
#define MII_LXT971_IER_IEN      0x00f2

#define MII_LXT971_ISR          19  /* Interrupt Status Register */
#define MII_LXT971_ISR_MASK     0x00f0

/* register definitions for the 973 */
#define MII_LXT973_PCR 16 /* Port Configuration Register */
#define PCR_FIBER_SELECT 1

MODULE_DESCRIPTION("Intel LXT PHY driver");
MODULE_AUTHOR("Andy Fleming");
MODULE_LICENSE("GPL");

static int lxt970_ack_interrupt(struct phy_device *phydev)
{
        int err;

        err = phy_read(phydev, MII_BMSR);

        if (err < 0)
                return err;

        err = phy_read(phydev, MII_LXT970_ISR);

        if (err < 0)
                return err;

        return 0;
}

static int lxt970_config_intr(struct phy_device *phydev)
{
        int err;

        if (phydev->interrupts == PHY_INTERRUPT_ENABLED) {
                err = lxt970_ack_interrupt(phydev);
                if (err)
                        return err;

                err = phy_write(phydev, MII_LXT970_IER, MII_LXT970_IER_IEN);
        } else {
                err = phy_write(phydev, MII_LXT970_IER, 0);
                if (err)
                        return err;

                err = lxt970_ack_interrupt(phydev);
        }

        return err;
}

static irqreturn_t lxt970_handle_interrupt(struct phy_device *phydev)
{
        int irq_status;

        /* The interrupt status register is cleared by reading BMSR
         * followed by MII_LXT970_ISR
         */
        irq_status = phy_read(phydev, MII_BMSR);
        if (irq_status < 0) {
                phy_error(phydev);
                return IRQ_NONE;
        }

        irq_status = phy_read(phydev, MII_LXT970_ISR);
        if (irq_status < 0) {
                phy_error(phydev);
                return IRQ_NONE;
        }

        if (!(irq_status & MII_LXT970_IRS_MINT))
                return IRQ_NONE;

        phy_trigger_machine(phydev);

        return IRQ_HANDLED;
}

static int lxt970_config_init(struct phy_device *phydev)
{
        return phy_write(phydev, MII_LXT970_CONFIG, 0);
}


static int lxt971_ack_interrupt(struct phy_device *phydev)
{
        int err = phy_read(phydev, MII_LXT971_ISR);

        if (err < 0)
                return err;

        return 0;
}

static int lxt971_config_intr(struct phy_device *phydev)
{
        int err;

        if (phydev->interrupts == PHY_INTERRUPT_ENABLED) {
                err = lxt971_ack_interrupt(phydev);
                if (err)
                        return err;

                err = phy_write(phydev, MII_LXT971_IER, MII_LXT971_IER_IEN);
        } else {
                err = phy_write(phydev, MII_LXT971_IER, 0);
                if (err)
                        return err;

                err = lxt971_ack_interrupt(phydev);
        }

        return err;
}

static irqreturn_t lxt971_handle_interrupt(struct phy_device *phydev)
{
        int irq_status;

        irq_status = phy_read(phydev, MII_LXT971_ISR);
        if (irq_status < 0) {
                phy_error(phydev);
                return IRQ_NONE;
        }

        if (!(irq_status & MII_LXT971_ISR_MASK))
                return IRQ_NONE;

        phy_trigger_machine(phydev);

        return IRQ_HANDLED;
}

/*
 * A2 version of LXT973 chip has an ERRATA: it randomly return the contents
 * of the previous even register when you read a odd register regularly
 */

static int lxt973a2_update_link(struct phy_device *phydev)
{
        int status;
        int control;
        int retry = 8; /* we try 8 times */

        /* Do a fake read */
        status = phy_read(phydev, MII_BMSR);

        if (status < 0)
                return status;

        control = phy_read(phydev, MII_BMCR);
        if (control < 0)
                return control;

        do {
                /* Read link and autonegotiation status */
                status = phy_read(phydev, MII_BMSR);
        } while (status >= 0 && retry-- && status == control);

        if (status < 0)
                return status;

        if ((status & BMSR_LSTATUS) == 0)
                phydev->link = 0;
        else
                phydev->link = 1;

        return 0;
}

static int lxt973a2_read_status(struct phy_device *phydev)
{
        int adv;
        int err;
        int lpa;

        /* Update the link, but return if there was an error */
        err = lxt973a2_update_link(phydev);
        if (err)
                return err;

        if (AUTONEG_ENABLE == phydev->autoneg) {
                int retry = 1;

                adv = phy_read(phydev, MII_ADVERTISE);

                if (adv < 0)
                        return adv;

                do {
                        lpa = phy_read(phydev, MII_LPA);

                        if (lpa < 0)
                                return lpa;

                        /* If both registers are equal, it is suspect but not
                         * impossible, hence a new try
                         */
                } while (lpa == adv && retry--);

                mii_lpa_to_linkmode_lpa_t(phydev->lp_advertising, lpa);

                lpa &= adv;

                phydev->speed = SPEED_10;
                phydev->duplex = DUPLEX_HALF;
                phydev->pause = phydev->asym_pause = 0;

                if (lpa & (LPA_100FULL | LPA_100HALF)) {
                        phydev->speed = SPEED_100;

                        if (lpa & LPA_100FULL)
                                phydev->duplex = DUPLEX_FULL;
                } else {
                        if (lpa & LPA_10FULL)
                                phydev->duplex = DUPLEX_FULL;
                }

                phy_resolve_aneg_pause(phydev);
        } else {
                err = genphy_read_status_fixed(phydev);
                if (err < 0)
                        return err;

                phydev->pause = phydev->asym_pause = 0;
                linkmode_zero(phydev->lp_advertising);
        }

        return 0;
}

static int lxt973_probe(struct phy_device *phydev)
{
        int val = phy_read(phydev, MII_LXT973_PCR);

        if (val & PCR_FIBER_SELECT) {
                /*
                 * If fiber is selected, then the only correct setting
                 * is 100Mbps, full duplex, and auto negotiation off.
                 */
                val = phy_read(phydev, MII_BMCR);
                val |= (BMCR_SPEED100 | BMCR_FULLDPLX);
                val &= ~BMCR_ANENABLE;
                phy_write(phydev, MII_BMCR, val);
                /* Remember that the port is in fiber mode. */
                phydev->priv = lxt973_probe;
                phydev->port = PORT_FIBRE;
        } else {
                phydev->priv = NULL;
        }
        return 0;
}

static int lxt973_config_aneg(struct phy_device *phydev)
{
        /* Do nothing if port is in fiber mode. */
        return phydev->priv ? 0 : genphy_config_aneg(phydev);
}

static struct phy_driver lxt97x_driver[] = {
{
        .phy_id         = 0x78100000,
        .name           = "LXT970",
        .phy_id_mask    = 0xfffffff0,
        /* PHY_BASIC_FEATURES */
        .config_init    = lxt970_config_init,
        .config_intr    = lxt970_config_intr,
        .handle_interrupt = lxt970_handle_interrupt,
}, {
        .phy_id         = 0x001378e0,
        .name           = "LXT971",
        .phy_id_mask    = 0xfffffff0,
        /* PHY_BASIC_FEATURES */
        .config_intr    = lxt971_config_intr,
        .handle_interrupt = lxt971_handle_interrupt,
        .suspend        = genphy_suspend,
        .resume         = genphy_resume,
}, {
        .phy_id         = 0x00137a10,
        .name           = "LXT973-A2",
        .phy_id_mask    = 0xffffffff,
        /* PHY_BASIC_FEATURES */
        .flags          = 0,
        .probe          = lxt973_probe,
        .config_aneg    = lxt973_config_aneg,
        .read_status    = lxt973a2_read_status,
        .suspend        = genphy_suspend,
        .resume         = genphy_resume,
}, {
        .phy_id         = 0x00137a10,
        .name           = "LXT973",
        .phy_id_mask    = 0xfffffff0,
        /* PHY_BASIC_FEATURES */
        .flags          = 0,
        .probe          = lxt973_probe,
        .config_aneg    = lxt973_config_aneg,
        .suspend        = genphy_suspend,
        .resume         = genphy_resume,
} };

module_phy_driver(lxt97x_driver);

static struct mdio_device_id __maybe_unused lxt_tbl[] = {
        { 0x78100000, 0xfffffff0 },
        { 0x001378e0, 0xfffffff0 },
        { 0x00137a10, 0xfffffff0 },
        { }
};

MODULE_DEVICE_TABLE(mdio, lxt_tbl);