// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Marvell 88E6352 family SERDES PCS support
 *
 * Copyright (c) 2008 Marvell Semiconductor
 *
 * Copyright (c) 2017 Andrew Lunn <andrew@lunn.ch>
 */
#include <linux/phylink.h>

#include "global2.h"
#include "port.h"
#include "serdes.h"

/* Definitions from drivers/net/phy/marvell.c, which would be good to reuse. */
#define MII_M1011_PHY_STATUS            17
#define MII_M1011_IMASK                 18
#define MII_M1011_IMASK_LINK_CHANGE     BIT(10)
#define MII_M1011_IEVENT                19
#define MII_M1011_IEVENT_LINK_CHANGE    BIT(10)
#define MII_MARVELL_PHY_PAGE            22
#define MII_MARVELL_FIBER_PAGE          1

struct marvell_c22_pcs {
        struct mdio_device mdio;
        struct phylink_pcs phylink_pcs;
        unsigned int irq;
        char name[64];
        bool (*link_check)(struct marvell_c22_pcs *mpcs);
        struct mv88e6xxx_port *port;
};

static struct marvell_c22_pcs *pcs_to_marvell_c22_pcs(struct phylink_pcs *pcs)
{
        return container_of(pcs, struct marvell_c22_pcs, phylink_pcs);
}

static int marvell_c22_pcs_set_fiber_page(struct marvell_c22_pcs *mpcs)
{
        u16 page;
        int err;

        mutex_lock(&mpcs->mdio.bus->mdio_lock);

        err = __mdiodev_read(&mpcs->mdio, MII_MARVELL_PHY_PAGE);
        if (err < 0) {
                dev_err(mpcs->mdio.dev.parent,
                        "%s: can't read Serdes page register: %pe\n",
                        mpcs->name, ERR_PTR(err));
                return err;
        }

        page = err;

        err = __mdiodev_write(&mpcs->mdio, MII_MARVELL_PHY_PAGE,
                              MII_MARVELL_FIBER_PAGE);
        if (err) {
                dev_err(mpcs->mdio.dev.parent,
                        "%s: can't set Serdes page register: %pe\n",
                        mpcs->name, ERR_PTR(err));
                return err;
        }

        return page;
}

static int marvell_c22_pcs_restore_page(struct marvell_c22_pcs *mpcs,
                                        int oldpage, int ret)
{
        int err;

        if (oldpage >= 0) {
                err = __mdiodev_write(&mpcs->mdio, MII_MARVELL_PHY_PAGE,
                                      oldpage);
                if (err)
                        dev_err(mpcs->mdio.dev.parent,
                                "%s: can't restore Serdes page register: %pe\n",
                                mpcs->name, ERR_PTR(err));
                if (!err || ret < 0)
                        err = ret;
        } else {
                err = oldpage;
        }
        mutex_unlock(&mpcs->mdio.bus->mdio_lock);

        return err;
}

static irqreturn_t marvell_c22_pcs_handle_irq(int irq, void *dev_id)
{
        struct marvell_c22_pcs *mpcs = dev_id;
        irqreturn_t status = IRQ_NONE;
        int err, oldpage;

        oldpage = marvell_c22_pcs_set_fiber_page(mpcs);
        if (oldpage < 0)
                goto fail;

        err = __mdiodev_read(&mpcs->mdio, MII_M1011_IEVENT);
        if (err >= 0 && err & MII_M1011_IEVENT_LINK_CHANGE) {
                phylink_pcs_change(&mpcs->phylink_pcs, true);
                status = IRQ_HANDLED;
        }

fail:
        marvell_c22_pcs_restore_page(mpcs, oldpage, 0);

        return status;
}

static int marvell_c22_pcs_modify(struct marvell_c22_pcs *mpcs, u8 reg,
                                  u16 mask, u16 val)
{
        int oldpage, err = 0;

        oldpage = marvell_c22_pcs_set_fiber_page(mpcs);
        if (oldpage >= 0)
                err = __mdiodev_modify(&mpcs->mdio, reg, mask, val);

        return marvell_c22_pcs_restore_page(mpcs, oldpage, err);
}

static int marvell_c22_pcs_power(struct marvell_c22_pcs *mpcs,
                                 bool on)
{
        u16 val = on ? 0 : BMCR_PDOWN;

        return marvell_c22_pcs_modify(mpcs, MII_BMCR, BMCR_PDOWN, val);
}

static int marvell_c22_pcs_control_irq(struct marvell_c22_pcs *mpcs,
                                       bool enable)
{
        u16 val = enable ? MII_M1011_IMASK_LINK_CHANGE : 0;

        return marvell_c22_pcs_modify(mpcs, MII_M1011_IMASK,
                                      MII_M1011_IMASK_LINK_CHANGE, val);
}

static int marvell_c22_pcs_enable(struct phylink_pcs *pcs)
{
        struct marvell_c22_pcs *mpcs = pcs_to_marvell_c22_pcs(pcs);
        int err;

        err = marvell_c22_pcs_power(mpcs, true);
        if (err)
                return err;

        return marvell_c22_pcs_control_irq(mpcs, !!mpcs->irq);
}

static void marvell_c22_pcs_disable(struct phylink_pcs *pcs)
{
        struct marvell_c22_pcs *mpcs = pcs_to_marvell_c22_pcs(pcs);

        marvell_c22_pcs_control_irq(mpcs, false);
        marvell_c22_pcs_power(mpcs, false);
}

static void marvell_c22_pcs_get_state(struct phylink_pcs *pcs,
                                      unsigned int neg_mode,
                                      struct phylink_link_state *state)
{
        struct marvell_c22_pcs *mpcs = pcs_to_marvell_c22_pcs(pcs);
        int oldpage, bmsr, lpa, status;

        state->link = false;

        if (mpcs->link_check && !mpcs->link_check(mpcs))
                return;

        oldpage = marvell_c22_pcs_set_fiber_page(mpcs);
        if (oldpage >= 0) {
                bmsr = __mdiodev_read(&mpcs->mdio, MII_BMSR);
                lpa = __mdiodev_read(&mpcs->mdio, MII_LPA);
                status = __mdiodev_read(&mpcs->mdio, MII_M1011_PHY_STATUS);
        }

        if (marvell_c22_pcs_restore_page(mpcs, oldpage, 0) >= 0 &&
            bmsr >= 0 && lpa >= 0 && status >= 0)
                mv88e6xxx_pcs_decode_state(mpcs->mdio.dev.parent, bmsr, lpa,
                                           status, state);
}

static int marvell_c22_pcs_config(struct phylink_pcs *pcs,
                                  unsigned int neg_mode,
                                  phy_interface_t interface,
                                  const unsigned long *advertising,
                                  bool permit_pause_to_mac)
{
        struct marvell_c22_pcs *mpcs = pcs_to_marvell_c22_pcs(pcs);
        int oldpage, adv, err, ret = 0;
        u16 bmcr;

        adv = phylink_mii_c22_pcs_encode_advertisement(interface, advertising);
        if (adv < 0)
                return 0;

        bmcr = neg_mode == PHYLINK_PCS_NEG_INBAND_ENABLED ? BMCR_ANENABLE : 0;

        oldpage = marvell_c22_pcs_set_fiber_page(mpcs);
        if (oldpage < 0)
                goto restore;

        err = __mdiodev_modify_changed(&mpcs->mdio, MII_ADVERTISE, 0xffff, adv);
        ret = err;
        if (err < 0)
                goto restore;

        err = __mdiodev_modify_changed(&mpcs->mdio, MII_BMCR, BMCR_ANENABLE,
                                       bmcr);
        if (err < 0) {
                ret = err;
                goto restore;
        }

        /* If the ANENABLE bit was changed, the PHY will restart negotiation,
         * so we don't need to flag a change to trigger its own restart.
         */
        if (err)
                ret = 0;

restore:
        return marvell_c22_pcs_restore_page(mpcs, oldpage, ret);
}

static void marvell_c22_pcs_an_restart(struct phylink_pcs *pcs)
{
        struct marvell_c22_pcs *mpcs = pcs_to_marvell_c22_pcs(pcs);

        marvell_c22_pcs_modify(mpcs, MII_BMCR, BMCR_ANRESTART, BMCR_ANRESTART);
}

static void marvell_c22_pcs_link_up(struct phylink_pcs *pcs, unsigned int mode,
                                    phy_interface_t interface, int speed,
                                    int duplex)
{
        struct marvell_c22_pcs *mpcs = pcs_to_marvell_c22_pcs(pcs);
        u16 bmcr;
        int err;

        if (phylink_autoneg_inband(mode))
                return;

        bmcr = mii_bmcr_encode_fixed(speed, duplex);

        err = marvell_c22_pcs_modify(mpcs, MII_BMCR, BMCR_SPEED100 |
                                     BMCR_FULLDPLX | BMCR_SPEED1000, bmcr);
        if (err)
                dev_err(mpcs->mdio.dev.parent,
                        "%s: failed to configure mpcs: %pe\n", mpcs->name,
                        ERR_PTR(err));
}

static const struct phylink_pcs_ops marvell_c22_pcs_ops = {
        .pcs_enable = marvell_c22_pcs_enable,
        .pcs_disable = marvell_c22_pcs_disable,
        .pcs_get_state = marvell_c22_pcs_get_state,
        .pcs_config = marvell_c22_pcs_config,
        .pcs_an_restart = marvell_c22_pcs_an_restart,
        .pcs_link_up = marvell_c22_pcs_link_up,
};

static struct marvell_c22_pcs *marvell_c22_pcs_alloc(struct device *dev,
                                                     struct mii_bus *bus,
                                                     unsigned int addr)
{
        struct marvell_c22_pcs *mpcs;

        mpcs = kzalloc_obj(*mpcs);
        if (!mpcs)
                return NULL;

        mpcs->mdio.dev.parent = dev;
        mpcs->mdio.bus = bus;
        mpcs->mdio.addr = addr;
        mpcs->phylink_pcs.ops = &marvell_c22_pcs_ops;

        return mpcs;
}

static int marvell_c22_pcs_setup_irq(struct marvell_c22_pcs *mpcs,
                                     unsigned int irq)
{
        int err;

        mpcs->phylink_pcs.poll = !irq;
        mpcs->irq = irq;

        if (irq) {
                err = request_threaded_irq(irq, NULL,
                                           marvell_c22_pcs_handle_irq,
                                           IRQF_ONESHOT, mpcs->name, mpcs);
                if (err)
                        return err;
        }

        return 0;
}

/* mv88e6352 specifics */

static bool mv88e6352_pcs_link_check(struct marvell_c22_pcs *mpcs)
{
        struct mv88e6xxx_port *port = mpcs->port;
        struct mv88e6xxx_chip *chip = port->chip;
        u8 cmode;

        /* Port 4 can be in auto-media mode. Check that the port is
         * associated with the mpcs.
         */
        mv88e6xxx_reg_lock(chip);
        chip->info->ops->port_get_cmode(chip, port->port, &cmode);
        mv88e6xxx_reg_unlock(chip);

        return cmode == MV88E6XXX_PORT_STS_CMODE_100BASEX ||
               cmode == MV88E6XXX_PORT_STS_CMODE_1000BASEX ||
               cmode == MV88E6XXX_PORT_STS_CMODE_SGMII;
}

static int mv88e6352_pcs_init(struct mv88e6xxx_chip *chip, int port)
{
        struct marvell_c22_pcs *mpcs;
        struct mii_bus *bus;
        struct device *dev;
        unsigned int irq;
        int err;

        mv88e6xxx_reg_lock(chip);
        err = mv88e6352_g2_scratch_port_has_serdes(chip, port);
        mv88e6xxx_reg_unlock(chip);
        if (err <= 0)
                return err;

        irq = mv88e6xxx_serdes_irq_mapping(chip, port);
        bus = mv88e6xxx_default_mdio_bus(chip);
        dev = chip->dev;

        mpcs = marvell_c22_pcs_alloc(dev, bus, MV88E6352_ADDR_SERDES);
        if (!mpcs)
                return -ENOMEM;

        snprintf(mpcs->name, sizeof(mpcs->name),
                 "mv88e6xxx-%s-serdes-%d", dev_name(dev), port);

        mpcs->link_check = mv88e6352_pcs_link_check;
        mpcs->port = &chip->ports[port];

        err = marvell_c22_pcs_setup_irq(mpcs, irq);
        if (err) {
                kfree(mpcs);
                return err;
        }

        chip->ports[port].pcs_private = &mpcs->phylink_pcs;

        return 0;
}

static void mv88e6352_pcs_teardown(struct mv88e6xxx_chip *chip, int port)
{
        struct marvell_c22_pcs *mpcs;
        struct phylink_pcs *pcs;

        pcs = chip->ports[port].pcs_private;
        if (!pcs)
                return;

        mpcs = pcs_to_marvell_c22_pcs(pcs);

        if (mpcs->irq)
                free_irq(mpcs->irq, mpcs);

        kfree(mpcs);

        chip->ports[port].pcs_private = NULL;
}

static struct phylink_pcs *mv88e6352_pcs_select(struct mv88e6xxx_chip *chip,
                                                int port,
                                                phy_interface_t interface)
{
        return chip->ports[port].pcs_private;
}

const struct mv88e6xxx_pcs_ops mv88e6352_pcs_ops = {
        .pcs_init = mv88e6352_pcs_init,
        .pcs_teardown = mv88e6352_pcs_teardown,
        .pcs_select = mv88e6352_pcs_select,
};