// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * drivers/net/ethernet/ibm/emac/zmii.c
 *
 * Driver for PowerPC 4xx on-chip ethernet controller, ZMII bridge support.
 *
 * Copyright 2007 Benjamin Herrenschmidt, IBM Corp.
 *                <benh@kernel.crashing.org>
 *
 * Based on the arch/ppc version of the driver:
 *
 * Copyright (c) 2004, 2005 Zultys Technologies.
 * Eugene Surovegin <eugene.surovegin@zultys.com> or <ebs@ebshome.net>
 *
 * Based on original work by
 *      Armin Kuster <akuster@mvista.com>
 *      Copyright 2001 MontaVista Softare Inc.
 */
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/ethtool.h>
#include <linux/mod_devicetable.h>
#include <linux/of_address.h>
#include <linux/platform_device.h>
#include <asm/io.h>

#include "emac.h"
#include "core.h"

/* ZMIIx_FER */
#define ZMII_FER_MDI(idx)       (0x80000000 >> ((idx) * 4))
#define ZMII_FER_MDI_ALL        (ZMII_FER_MDI(0) | ZMII_FER_MDI(1) | \
                                 ZMII_FER_MDI(2) | ZMII_FER_MDI(3))

#define ZMII_FER_SMII(idx)      (0x40000000 >> ((idx) * 4))
#define ZMII_FER_RMII(idx)      (0x20000000 >> ((idx) * 4))
#define ZMII_FER_MII(idx)       (0x10000000 >> ((idx) * 4))

/* ZMIIx_SSR */
#define ZMII_SSR_SCI(idx)       (0x40000000 >> ((idx) * 4))
#define ZMII_SSR_FSS(idx)       (0x20000000 >> ((idx) * 4))
#define ZMII_SSR_SP(idx)        (0x10000000 >> ((idx) * 4))

/* ZMII only supports MII, RMII and SMII
 * we also support autodetection for backward compatibility
 */
static inline int zmii_valid_mode(int mode)
{
        return  mode == PHY_INTERFACE_MODE_MII ||
                mode == PHY_INTERFACE_MODE_RMII ||
                mode == PHY_INTERFACE_MODE_SMII ||
                mode == PHY_INTERFACE_MODE_NA;
}

static inline const char *zmii_mode_name(int mode)
{
        switch (mode) {
        case PHY_INTERFACE_MODE_MII:
                return "MII";
        case PHY_INTERFACE_MODE_RMII:
                return "RMII";
        case PHY_INTERFACE_MODE_SMII:
                return "SMII";
        default:
                BUG();
        }
}

static inline u32 zmii_mode_mask(int mode, int input)
{
        switch (mode) {
        case PHY_INTERFACE_MODE_MII:
                return ZMII_FER_MII(input);
        case PHY_INTERFACE_MODE_RMII:
                return ZMII_FER_RMII(input);
        case PHY_INTERFACE_MODE_SMII:
                return ZMII_FER_SMII(input);
        default:
                return 0;
        }
}

int zmii_attach(struct platform_device *ofdev, int input,
                phy_interface_t *mode)
{
        struct zmii_instance *dev = platform_get_drvdata(ofdev);
        struct zmii_regs __iomem *p = dev->base;

        ZMII_DBG(dev, "init(%d, %d)" NL, input, *mode);

        if (!zmii_valid_mode(*mode)) {
                /* Probably an EMAC connected to RGMII,
                 * but it still may need ZMII for MDIO so
                 * we don't fail here.
                 */
                dev->users++;
                return 0;
        }

        mutex_lock(&dev->lock);

        /* Autodetect ZMII mode if not specified.
         * This is only for backward compatibility with the old driver.
         * Please, always specify PHY mode in your board port to avoid
         * any surprises.
         */
        if (dev->mode == PHY_INTERFACE_MODE_NA) {
                if (*mode == PHY_INTERFACE_MODE_NA) {
                        u32 r = dev->fer_save;

                        ZMII_DBG(dev, "autodetecting mode, FER = 0x%08x" NL, r);

                        if (r & (ZMII_FER_MII(0) | ZMII_FER_MII(1)))
                                dev->mode = PHY_INTERFACE_MODE_MII;
                        else if (r & (ZMII_FER_RMII(0) | ZMII_FER_RMII(1)))
                                dev->mode = PHY_INTERFACE_MODE_RMII;
                        else
                                dev->mode = PHY_INTERFACE_MODE_SMII;
                } else {
                        dev->mode = *mode;
                }
                printk(KERN_NOTICE "%pOF: bridge in %s mode\n",
                       ofdev->dev.of_node,
                       zmii_mode_name(dev->mode));
        } else {
                /* All inputs must use the same mode */
                if (*mode != PHY_INTERFACE_MODE_NA && *mode != dev->mode) {
                        printk(KERN_ERR
                               "%pOF: invalid mode %d specified for input %d\n",
                               ofdev->dev.of_node, *mode, input);
                        mutex_unlock(&dev->lock);
                        return -EINVAL;
                }
        }

        /* Report back correct PHY mode,
         * it may be used during PHY initialization.
         */
        *mode = dev->mode;

        /* Enable this input */
        out_be32(&p->fer, in_be32(&p->fer) | zmii_mode_mask(dev->mode, input));
        ++dev->users;

        mutex_unlock(&dev->lock);

        return 0;
}

void zmii_get_mdio(struct platform_device *ofdev, int input)
{
        struct zmii_instance *dev = platform_get_drvdata(ofdev);
        u32 fer;

        ZMII_DBG2(dev, "get_mdio(%d)" NL, input);

        mutex_lock(&dev->lock);

        fer = in_be32(&dev->base->fer) & ~ZMII_FER_MDI_ALL;
        out_be32(&dev->base->fer, fer | ZMII_FER_MDI(input));
}

void zmii_put_mdio(struct platform_device *ofdev, int input)
{
        struct zmii_instance *dev = platform_get_drvdata(ofdev);

        ZMII_DBG2(dev, "put_mdio(%d)" NL, input);
        mutex_unlock(&dev->lock);
}


void zmii_set_speed(struct platform_device *ofdev, int input, int speed)
{
        struct zmii_instance *dev = platform_get_drvdata(ofdev);
        u32 ssr;

        mutex_lock(&dev->lock);

        ssr = in_be32(&dev->base->ssr);

        ZMII_DBG(dev, "speed(%d, %d)" NL, input, speed);

        if (speed == SPEED_100)
                ssr |= ZMII_SSR_SP(input);
        else
                ssr &= ~ZMII_SSR_SP(input);

        out_be32(&dev->base->ssr, ssr);

        mutex_unlock(&dev->lock);
}

void zmii_detach(struct platform_device *ofdev, int input)
{
        struct zmii_instance *dev = platform_get_drvdata(ofdev);

        BUG_ON(!dev || dev->users == 0);

        mutex_lock(&dev->lock);

        ZMII_DBG(dev, "detach(%d)" NL, input);

        /* Disable this input */
        out_be32(&dev->base->fer,
                 in_be32(&dev->base->fer) & ~zmii_mode_mask(dev->mode, input));

        --dev->users;

        mutex_unlock(&dev->lock);
}

int zmii_get_regs_len(struct platform_device *ofdev)
{
        return sizeof(struct emac_ethtool_regs_subhdr) +
                sizeof(struct zmii_regs);
}

void *zmii_dump_regs(struct platform_device *ofdev, void *buf)
{
        struct zmii_instance *dev = platform_get_drvdata(ofdev);
        struct emac_ethtool_regs_subhdr *hdr = buf;
        struct zmii_regs *regs = (struct zmii_regs *)(hdr + 1);

        hdr->version = 0;
        hdr->index = 0; /* for now, are there chips with more than one
                         * zmii ? if yes, then we'll add a cell_index
                         * like we do for emac
                         */
        memcpy_fromio(regs, dev->base, sizeof(struct zmii_regs));
        return regs + 1;
}

static int zmii_probe(struct platform_device *ofdev)
{
        struct zmii_instance *dev;
        int err;

        dev = devm_kzalloc(&ofdev->dev, sizeof(struct zmii_instance),
                           GFP_KERNEL);
        if (!dev)
                return -ENOMEM;

        err = devm_mutex_init(&ofdev->dev, &dev->lock);
        if (err)
                return err;

        dev->ofdev = ofdev;
        dev->mode = PHY_INTERFACE_MODE_NA;

        dev->base = devm_platform_ioremap_resource(ofdev, 0);
        if (IS_ERR(dev->base)) {
                dev_err(&ofdev->dev, "can't map device registers");
                return PTR_ERR(dev->base);
        }

        /* We may need FER value for autodetection later */
        dev->fer_save = in_be32(&dev->base->fer);

        /* Disable all inputs by default */
        out_be32(&dev->base->fer, 0);

        printk(KERN_INFO "ZMII %pOF initialized\n", ofdev->dev.of_node);
        wmb();
        platform_set_drvdata(ofdev, dev);

        return 0;
}

static const struct of_device_id zmii_match[] =
{
        {
                .compatible     = "ibm,zmii",
        },
        /* For backward compat with old DT */
        {
                .type           = "emac-zmii",
        },
        {},
};

static struct platform_driver zmii_driver = {
        .driver = {
                .name = "emac-zmii",
                .of_match_table = zmii_match,
        },
        .probe = zmii_probe,
};

int __init zmii_init(void)
{
        return platform_driver_register(&zmii_driver);
}

void zmii_exit(void)
{
        platform_driver_unregister(&zmii_driver);
}