// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * drivers/net/ethernet/ibm/emac/rgmii.c
 *
 * Driver for PowerPC 4xx on-chip ethernet controller, RGMII 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
 *      Matt Porter <mporter@kernel.crashing.org>
 *      Copyright 2004 MontaVista Software, Inc.
 */
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/ethtool.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/platform_device.h>
#include <asm/io.h>

#include "emac.h"
#include "debug.h"

// XXX FIXME: Axon seems to support a subset of the RGMII, we
// thus need to take that into account and possibly change some
// of the bit settings below that don't seem to quite match the
// AXON spec

/* RGMIIx_FER */
#define RGMII_FER_MASK(idx)     (0x7 << ((idx) * 4))
#define RGMII_FER_RTBI(idx)     (0x4 << ((idx) * 4))
#define RGMII_FER_RGMII(idx)    (0x5 << ((idx) * 4))
#define RGMII_FER_TBI(idx)      (0x6 << ((idx) * 4))
#define RGMII_FER_GMII(idx)     (0x7 << ((idx) * 4))
#define RGMII_FER_MII(idx)      RGMII_FER_GMII(idx)

/* RGMIIx_SSR */
#define RGMII_SSR_MASK(idx)     (0x7 << ((idx) * 8))
#define RGMII_SSR_10(idx)       (0x1 << ((idx) * 8))
#define RGMII_SSR_100(idx)      (0x2 << ((idx) * 8))
#define RGMII_SSR_1000(idx)     (0x4 << ((idx) * 8))

/* RGMII bridge supports only GMII/TBI and RGMII/RTBI PHYs */
static inline int rgmii_valid_mode(int phy_mode)
{
        return  phy_interface_mode_is_rgmii(phy_mode) ||
                phy_mode == PHY_INTERFACE_MODE_GMII ||
                phy_mode == PHY_INTERFACE_MODE_MII ||
                phy_mode == PHY_INTERFACE_MODE_TBI ||
                phy_mode == PHY_INTERFACE_MODE_RTBI;
}

static inline u32 rgmii_mode_mask(int mode, int input)
{
        switch (mode) {
        case PHY_INTERFACE_MODE_RGMII:
        case PHY_INTERFACE_MODE_RGMII_ID:
        case PHY_INTERFACE_MODE_RGMII_RXID:
        case PHY_INTERFACE_MODE_RGMII_TXID:
                return RGMII_FER_RGMII(input);
        case PHY_INTERFACE_MODE_TBI:
                return RGMII_FER_TBI(input);
        case PHY_INTERFACE_MODE_GMII:
                return RGMII_FER_GMII(input);
        case PHY_INTERFACE_MODE_MII:
                return RGMII_FER_MII(input);
        case PHY_INTERFACE_MODE_RTBI:
                return RGMII_FER_RTBI(input);
        default:
                BUG();
        }
}

int rgmii_attach(struct platform_device *ofdev, int input, int mode)
{
        struct rgmii_instance *dev = platform_get_drvdata(ofdev);
        struct rgmii_regs __iomem *p = dev->base;

        RGMII_DBG(dev, "attach(%d)" NL, input);

        /* Check if we need to attach to a RGMII */
        if (input < 0 || !rgmii_valid_mode(mode)) {
                printk(KERN_ERR "%pOF: unsupported settings !\n",
                       ofdev->dev.of_node);
                return -ENODEV;
        }

        mutex_lock(&dev->lock);

        /* Enable this input */
        out_be32(&p->fer, in_be32(&p->fer) | rgmii_mode_mask(mode, input));

        printk(KERN_NOTICE "%pOF: input %d in %s mode\n",
               ofdev->dev.of_node, input, phy_modes(mode));

        ++dev->users;

        mutex_unlock(&dev->lock);

        return 0;
}

void rgmii_set_speed(struct platform_device *ofdev, int input, int speed)
{
        struct rgmii_instance *dev = platform_get_drvdata(ofdev);
        struct rgmii_regs __iomem *p = dev->base;
        u32 ssr;

        mutex_lock(&dev->lock);

        ssr = in_be32(&p->ssr) & ~RGMII_SSR_MASK(input);

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

        if (speed == SPEED_1000)
                ssr |= RGMII_SSR_1000(input);
        else if (speed == SPEED_100)
                ssr |= RGMII_SSR_100(input);
        else if (speed == SPEED_10)
                ssr |= RGMII_SSR_10(input);

        out_be32(&p->ssr, ssr);

        mutex_unlock(&dev->lock);
}

void rgmii_get_mdio(struct platform_device *ofdev, int input)
{
        struct rgmii_instance *dev = platform_get_drvdata(ofdev);
        struct rgmii_regs __iomem *p = dev->base;
        u32 fer;

        RGMII_DBG2(dev, "get_mdio(%d)" NL, input);

        if (!(dev->flags & EMAC_RGMII_FLAG_HAS_MDIO))
                return;

        mutex_lock(&dev->lock);

        fer = in_be32(&p->fer);
        fer |= 0x00080000u >> input;
        out_be32(&p->fer, fer);
        (void)in_be32(&p->fer);

        DBG2(dev, " fer = 0x%08x\n", fer);
}

void rgmii_put_mdio(struct platform_device *ofdev, int input)
{
        struct rgmii_instance *dev = platform_get_drvdata(ofdev);
        struct rgmii_regs __iomem *p = dev->base;
        u32 fer;

        RGMII_DBG2(dev, "put_mdio(%d)" NL, input);

        if (!(dev->flags & EMAC_RGMII_FLAG_HAS_MDIO))
                return;

        fer = in_be32(&p->fer);
        fer &= ~(0x00080000u >> input);
        out_be32(&p->fer, fer);
        (void)in_be32(&p->fer);

        DBG2(dev, " fer = 0x%08x\n", fer);

        mutex_unlock(&dev->lock);
}

void rgmii_detach(struct platform_device *ofdev, int input)
{
        struct rgmii_instance *dev = platform_get_drvdata(ofdev);
        struct rgmii_regs __iomem *p;

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

        mutex_lock(&dev->lock);

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

        /* Disable this input */
        out_be32(&p->fer, in_be32(&p->fer) & ~RGMII_FER_MASK(input));

        --dev->users;

        mutex_unlock(&dev->lock);
}

int rgmii_get_regs_len(struct platform_device *ofdev)
{
        return sizeof(struct emac_ethtool_regs_subhdr) +
                sizeof(struct rgmii_regs);
}

void *rgmii_dump_regs(struct platform_device *ofdev, void *buf)
{
        struct rgmii_instance *dev = platform_get_drvdata(ofdev);
        struct emac_ethtool_regs_subhdr *hdr = buf;
        struct rgmii_regs *regs = (struct rgmii_regs *)(hdr + 1);

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


static int rgmii_probe(struct platform_device *ofdev)
{
        struct rgmii_instance *dev;
        int err;

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

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

        dev->ofdev = ofdev;

        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);
        }

        /* Check for RGMII flags */
        if (of_property_read_bool(ofdev->dev.of_node, "has-mdio"))
                dev->flags |= EMAC_RGMII_FLAG_HAS_MDIO;

        /* CAB lacks the right properties, fix this up */
        if (of_device_is_compatible(ofdev->dev.of_node, "ibm,rgmii-axon"))
                dev->flags |= EMAC_RGMII_FLAG_HAS_MDIO;

        DBG2(dev, " Boot FER = 0x%08x, SSR = 0x%08x\n",
             in_be32(&dev->base->fer), in_be32(&dev->base->ssr));

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

        printk(KERN_INFO
               "RGMII %pOF initialized with%s MDIO support\n",
               ofdev->dev.of_node,
               (dev->flags & EMAC_RGMII_FLAG_HAS_MDIO) ? "" : "out");

        wmb();
        platform_set_drvdata(ofdev, dev);

        return 0;
}

static const struct of_device_id rgmii_match[] =
{
        {
                .compatible     = "ibm,rgmii",
        },
        {
                .type           = "emac-rgmii",
        },
        {},
};

static struct platform_driver rgmii_driver = {
        .driver = {
                .name = "emac-rgmii",
                .of_match_table = rgmii_match,
        },
        .probe = rgmii_probe,
};

int __init rgmii_init(void)
{
        return platform_driver_register(&rgmii_driver);
}

void rgmii_exit(void)
{
        platform_driver_unregister(&rgmii_driver);
}