// SPDX-License-Identifier: GPL-2.0-only
/*
 * mdio.c: Generic support for MDIO-compatible transceivers
 * Copyright 2006-2009 Solarflare Communications Inc.
 */

#include <linux/kernel.h>
#include <linux/capability.h>
#include <linux/errno.h>
#include <linux/ethtool.h>
#include <linux/mdio.h>
#include <linux/module.h>

MODULE_DESCRIPTION("Generic support for MDIO-compatible transceivers");
MODULE_AUTHOR("Copyright 2006-2009 Solarflare Communications Inc.");
MODULE_LICENSE("GPL");

/**
 * mdio45_probe - probe for an MDIO (clause 45) device
 * @mdio: MDIO interface
 * @prtad: Expected PHY address
 *
 * This sets @prtad and @mmds in the MDIO interface if successful.
 * Returns 0 on success, negative on error.
 */
int mdio45_probe(struct mdio_if_info *mdio, int prtad)
{
        int mmd, stat2, devs1, devs2;

        /* Assume PHY must have at least one of PMA/PMD, WIS, PCS, PHY
         * XS or DTE XS; give up if none is present. */
        for (mmd = 1; mmd <= 5; mmd++) {
                /* Is this MMD present? */
                stat2 = mdio->mdio_read(mdio->dev, prtad, mmd, MDIO_STAT2);
                if (stat2 < 0 ||
                    (stat2 & MDIO_STAT2_DEVPRST) != MDIO_STAT2_DEVPRST_VAL)
                        continue;

                /* It should tell us about all the other MMDs */
                devs1 = mdio->mdio_read(mdio->dev, prtad, mmd, MDIO_DEVS1);
                devs2 = mdio->mdio_read(mdio->dev, prtad, mmd, MDIO_DEVS2);
                if (devs1 < 0 || devs2 < 0)
                        continue;

                mdio->prtad = prtad;
                mdio->mmds = devs1 | (devs2 << 16);
                return 0;
        }

        return -ENODEV;
}
EXPORT_SYMBOL(mdio45_probe);

/**
 * mdio_set_flag - set or clear flag in an MDIO register
 * @mdio: MDIO interface
 * @prtad: PHY address
 * @devad: MMD address
 * @addr: Register address
 * @mask: Mask for flag (single bit set)
 * @sense: New value of flag
 *
 * This debounces changes: it does not write the register if the flag
 * already has the proper value.  Returns 0 on success, negative on error.
 */
int mdio_set_flag(const struct mdio_if_info *mdio,
                  int prtad, int devad, u16 addr, int mask,
                  bool sense)
{
        int old_val = mdio->mdio_read(mdio->dev, prtad, devad, addr);
        int new_val;

        if (old_val < 0)
                return old_val;
        if (sense)
                new_val = old_val | mask;
        else
                new_val = old_val & ~mask;
        if (old_val == new_val)
                return 0;
        return mdio->mdio_write(mdio->dev, prtad, devad, addr, new_val);
}
EXPORT_SYMBOL(mdio_set_flag);

/**
 * mdio45_links_ok - is link status up/OK
 * @mdio: MDIO interface
 * @mmd_mask: Mask for MMDs to check
 *
 * Returns 1 if the PHY reports link status up/OK, 0 otherwise.
 * @mmd_mask is normally @mdio->mmds, but if loopback is enabled
 * the MMDs being bypassed should be excluded from the mask.
 */
int mdio45_links_ok(const struct mdio_if_info *mdio, u32 mmd_mask)
{
        int devad, reg;

        if (!mmd_mask) {
                /* Use absence of XGMII faults in lieu of link state */
                reg = mdio->mdio_read(mdio->dev, mdio->prtad,
                                      MDIO_MMD_PHYXS, MDIO_STAT2);
                return reg >= 0 && !(reg & MDIO_STAT2_RXFAULT);
        }

        for (devad = 0; mmd_mask; devad++) {
                if (mmd_mask & (1 << devad)) {
                        mmd_mask &= ~(1 << devad);

                        /* Reset the latched status and fault flags */
                        mdio->mdio_read(mdio->dev, mdio->prtad,
                                        devad, MDIO_STAT1);
                        if (devad == MDIO_MMD_PMAPMD || devad == MDIO_MMD_PCS ||
                            devad == MDIO_MMD_PHYXS || devad == MDIO_MMD_DTEXS)
                                mdio->mdio_read(mdio->dev, mdio->prtad,
                                                devad, MDIO_STAT2);

                        /* Check the current status and fault flags */
                        reg = mdio->mdio_read(mdio->dev, mdio->prtad,
                                              devad, MDIO_STAT1);
                        if (reg < 0 ||
                            (reg & (MDIO_STAT1_FAULT | MDIO_STAT1_LSTATUS)) !=
                            MDIO_STAT1_LSTATUS)
                                return false;
                }
        }

        return true;
}
EXPORT_SYMBOL(mdio45_links_ok);

/**
 * mdio45_nway_restart - restart auto-negotiation for this interface
 * @mdio: MDIO interface
 *
 * Returns 0 on success, negative on error.
 */
int mdio45_nway_restart(const struct mdio_if_info *mdio)
{
        if (!(mdio->mmds & MDIO_DEVS_AN))
                return -EOPNOTSUPP;

        mdio_set_flag(mdio, mdio->prtad, MDIO_MMD_AN, MDIO_CTRL1,
                      MDIO_AN_CTRL1_RESTART, true);
        return 0;
}
EXPORT_SYMBOL(mdio45_nway_restart);

static u32 mdio45_get_an(const struct mdio_if_info *mdio, u16 addr)
{
        u32 result = 0;
        int reg;

        reg = mdio->mdio_read(mdio->dev, mdio->prtad, MDIO_MMD_AN, addr);
        if (reg & ADVERTISE_10HALF)
                result |= ADVERTISED_10baseT_Half;
        if (reg & ADVERTISE_10FULL)
                result |= ADVERTISED_10baseT_Full;
        if (reg & ADVERTISE_100HALF)
                result |= ADVERTISED_100baseT_Half;
        if (reg & ADVERTISE_100FULL)
                result |= ADVERTISED_100baseT_Full;
        if (reg & ADVERTISE_PAUSE_CAP)
                result |= ADVERTISED_Pause;
        if (reg & ADVERTISE_PAUSE_ASYM)
                result |= ADVERTISED_Asym_Pause;
        return result;
}

/**
 * mdio45_ethtool_ksettings_get_npage - get settings for ETHTOOL_GLINKSETTINGS
 * @mdio: MDIO interface
 * @cmd: Ethtool request structure
 * @npage_adv: Modes currently advertised on next pages
 * @npage_lpa: Modes advertised by link partner on next pages
 *
 * The @cmd parameter is expected to have been cleared before calling
 * mdio45_ethtool_ksettings_get_npage().
 *
 * Since the CSRs for auto-negotiation using next pages are not fully
 * standardised, this function does not attempt to decode them.  The
 * caller must pass them in.
 */
void mdio45_ethtool_ksettings_get_npage(const struct mdio_if_info *mdio,
                                        struct ethtool_link_ksettings *cmd,
                                        u32 npage_adv, u32 npage_lpa)
{
        int reg;
        u32 speed, supported = 0, advertising = 0, lp_advertising = 0;

        BUILD_BUG_ON(MDIO_SUPPORTS_C22 != ETH_MDIO_SUPPORTS_C22);
        BUILD_BUG_ON(MDIO_SUPPORTS_C45 != ETH_MDIO_SUPPORTS_C45);

        cmd->base.phy_address = mdio->prtad;
        cmd->base.mdio_support =
                mdio->mode_support & (MDIO_SUPPORTS_C45 | MDIO_SUPPORTS_C22);

        reg = mdio->mdio_read(mdio->dev, mdio->prtad, MDIO_MMD_PMAPMD,
                              MDIO_CTRL2);
        switch (reg & MDIO_PMA_CTRL2_TYPE) {
        case MDIO_PMA_CTRL2_10GBT:
        case MDIO_PMA_CTRL2_1000BT:
        case MDIO_PMA_CTRL2_100BTX:
        case MDIO_PMA_CTRL2_10BT:
                cmd->base.port = PORT_TP;
                supported = SUPPORTED_TP;
                reg = mdio->mdio_read(mdio->dev, mdio->prtad, MDIO_MMD_PMAPMD,
                                      MDIO_SPEED);
                if (reg & MDIO_SPEED_10G)
                        supported |= SUPPORTED_10000baseT_Full;
                if (reg & MDIO_PMA_SPEED_1000)
                        supported |= (SUPPORTED_1000baseT_Full |
                                            SUPPORTED_1000baseT_Half);
                if (reg & MDIO_PMA_SPEED_100)
                        supported |= (SUPPORTED_100baseT_Full |
                                            SUPPORTED_100baseT_Half);
                if (reg & MDIO_PMA_SPEED_10)
                        supported |= (SUPPORTED_10baseT_Full |
                                            SUPPORTED_10baseT_Half);
                advertising = ADVERTISED_TP;
                break;

        case MDIO_PMA_CTRL2_10GBCX4:
                cmd->base.port = PORT_OTHER;
                supported = 0;
                advertising = 0;
                break;

        case MDIO_PMA_CTRL2_10GBKX4:
        case MDIO_PMA_CTRL2_10GBKR:
        case MDIO_PMA_CTRL2_1000BKX:
                cmd->base.port = PORT_OTHER;
                supported = SUPPORTED_Backplane;
                reg = mdio->mdio_read(mdio->dev, mdio->prtad, MDIO_MMD_PMAPMD,
                                      MDIO_PMA_EXTABLE);
                if (reg & MDIO_PMA_EXTABLE_10GBKX4)
                        supported |= SUPPORTED_10000baseKX4_Full;
                if (reg & MDIO_PMA_EXTABLE_10GBKR)
                        supported |= SUPPORTED_10000baseKR_Full;
                if (reg & MDIO_PMA_EXTABLE_1000BKX)
                        supported |= SUPPORTED_1000baseKX_Full;
                reg = mdio->mdio_read(mdio->dev, mdio->prtad, MDIO_MMD_PMAPMD,
                                      MDIO_PMA_10GBR_FECABLE);
                if (reg & MDIO_PMA_10GBR_FECABLE_ABLE)
                        supported |= SUPPORTED_10000baseR_FEC;
                advertising = ADVERTISED_Backplane;
                break;

        /* All the other defined modes are flavours of optical */
        default:
                cmd->base.port = PORT_FIBRE;
                supported = SUPPORTED_FIBRE;
                advertising = ADVERTISED_FIBRE;
                break;
        }

        if (mdio->mmds & MDIO_DEVS_AN) {
                supported |= SUPPORTED_Autoneg;
                reg = mdio->mdio_read(mdio->dev, mdio->prtad, MDIO_MMD_AN,
                                      MDIO_CTRL1);
                if (reg & MDIO_AN_CTRL1_ENABLE) {
                        cmd->base.autoneg = AUTONEG_ENABLE;
                        advertising |=
                                ADVERTISED_Autoneg |
                                mdio45_get_an(mdio, MDIO_AN_ADVERTISE) |
                                npage_adv;
                } else {
                        cmd->base.autoneg = AUTONEG_DISABLE;
                }
        } else {
                cmd->base.autoneg = AUTONEG_DISABLE;
        }

        if (cmd->base.autoneg) {
                u32 modes = 0;
                int an_stat = mdio->mdio_read(mdio->dev, mdio->prtad,
                                              MDIO_MMD_AN, MDIO_STAT1);

                /* If AN is complete and successful, report best common
                 * mode, otherwise report best advertised mode.
                 */
                if (an_stat & MDIO_AN_STAT1_COMPLETE) {
                        lp_advertising =
                                mdio45_get_an(mdio, MDIO_AN_LPA) | npage_lpa;
                        if (an_stat & MDIO_AN_STAT1_LPABLE)
                                lp_advertising |= ADVERTISED_Autoneg;
                        modes = advertising & lp_advertising;
                }
                if ((modes & ~ADVERTISED_Autoneg) == 0)
                        modes = advertising;

                if (modes & (ADVERTISED_10000baseT_Full |
                             ADVERTISED_10000baseKX4_Full |
                             ADVERTISED_10000baseKR_Full)) {
                        speed = SPEED_10000;
                        cmd->base.duplex = DUPLEX_FULL;
                } else if (modes & (ADVERTISED_1000baseT_Full |
                                    ADVERTISED_1000baseT_Half |
                                    ADVERTISED_1000baseKX_Full)) {
                        speed = SPEED_1000;
                        cmd->base.duplex = !(modes & ADVERTISED_1000baseT_Half);
                } else if (modes & (ADVERTISED_100baseT_Full |
                                    ADVERTISED_100baseT_Half)) {
                        speed = SPEED_100;
                        cmd->base.duplex = !!(modes & ADVERTISED_100baseT_Full);
                } else {
                        speed = SPEED_10;
                        cmd->base.duplex = !!(modes & ADVERTISED_10baseT_Full);
                }
        } else {
                /* Report forced settings */
                reg = mdio->mdio_read(mdio->dev, mdio->prtad, MDIO_MMD_PMAPMD,
                                      MDIO_CTRL1);
                speed = (((reg & MDIO_PMA_CTRL1_SPEED1000) ? 100 : 1)
                         * ((reg & MDIO_PMA_CTRL1_SPEED100) ? 100 : 10));
                cmd->base.duplex = (reg & MDIO_CTRL1_FULLDPLX ||
                                    speed == SPEED_10000);
        }

        cmd->base.speed = speed;

        ethtool_convert_legacy_u32_to_link_mode(cmd->link_modes.supported,
                                                supported);
        ethtool_convert_legacy_u32_to_link_mode(cmd->link_modes.advertising,
                                                advertising);
        ethtool_convert_legacy_u32_to_link_mode(cmd->link_modes.lp_advertising,
                                                lp_advertising);

        /* 10GBASE-T MDI/MDI-X */
        if (cmd->base.port == PORT_TP && (cmd->base.speed == SPEED_10000)) {
                switch (mdio->mdio_read(mdio->dev, mdio->prtad, MDIO_MMD_PMAPMD,
                                        MDIO_PMA_10GBT_SWAPPOL)) {
                case MDIO_PMA_10GBT_SWAPPOL_ABNX | MDIO_PMA_10GBT_SWAPPOL_CDNX:
                        cmd->base.eth_tp_mdix = ETH_TP_MDI;
                        break;
                case 0:
                        cmd->base.eth_tp_mdix = ETH_TP_MDI_X;
                        break;
                default:
                        /* It's complicated... */
                        cmd->base.eth_tp_mdix = ETH_TP_MDI_INVALID;
                        break;
                }
        }
}
EXPORT_SYMBOL(mdio45_ethtool_ksettings_get_npage);

/**
 * mdio_mii_ioctl - MII ioctl interface for MDIO (clause 22 or 45) PHYs
 * @mdio: MDIO interface
 * @mii_data: MII ioctl data structure
 * @cmd: MII ioctl command
 *
 * Returns 0 on success, negative on error.
 */
int mdio_mii_ioctl(const struct mdio_if_info *mdio,
                   struct mii_ioctl_data *mii_data, int cmd)
{
        int prtad, devad;
        u16 addr = mii_data->reg_num;

        /* Validate/convert cmd to one of SIOC{G,S}MIIREG */
        switch (cmd) {
        case SIOCGMIIPHY:
                if (mdio->prtad == MDIO_PRTAD_NONE)
                        return -EOPNOTSUPP;
                mii_data->phy_id = mdio->prtad;
                cmd = SIOCGMIIREG;
                break;
        case SIOCGMIIREG:
        case SIOCSMIIREG:
                break;
        default:
                return -EOPNOTSUPP;
        }

        /* Validate/convert phy_id */
        if ((mdio->mode_support & MDIO_SUPPORTS_C45) &&
            mdio_phy_id_is_c45(mii_data->phy_id)) {
                prtad = mdio_phy_id_prtad(mii_data->phy_id);
                devad = mdio_phy_id_devad(mii_data->phy_id);
        } else if ((mdio->mode_support & MDIO_SUPPORTS_C22) &&
                   mii_data->phy_id < 0x20) {
                prtad = mii_data->phy_id;
                devad = MDIO_DEVAD_NONE;
                addr &= 0x1f;
        } else if ((mdio->mode_support & MDIO_EMULATE_C22) &&
                   mdio->prtad != MDIO_PRTAD_NONE &&
                   mii_data->phy_id == mdio->prtad) {
                /* Remap commonly-used MII registers. */
                prtad = mdio->prtad;
                switch (addr) {
                case MII_BMCR:
                case MII_BMSR:
                case MII_PHYSID1:
                case MII_PHYSID2:
                        devad = __ffs(mdio->mmds);
                        break;
                case MII_ADVERTISE:
                case MII_LPA:
                        if (!(mdio->mmds & MDIO_DEVS_AN))
                                return -EINVAL;
                        devad = MDIO_MMD_AN;
                        if (addr == MII_ADVERTISE)
                                addr = MDIO_AN_ADVERTISE;
                        else
                                addr = MDIO_AN_LPA;
                        break;
                default:
                        return -EINVAL;
                }
        } else {
                return -EINVAL;
        }

        if (cmd == SIOCGMIIREG) {
                int rc = mdio->mdio_read(mdio->dev, prtad, devad, addr);
                if (rc < 0)
                        return rc;
                mii_data->val_out = rc;
                return 0;
        } else {
                return mdio->mdio_write(mdio->dev, prtad, devad, addr,
                                        mii_data->val_in);
        }
}
EXPORT_SYMBOL(mdio_mii_ioctl);