// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * drivers/net/ethernet/ibm/emac/tah.c
 *
 * Driver for PowerPC 4xx on-chip ethernet controller, TAH support.
 *
 * Copyright 2007 Benjamin Herrenschmidt, IBM Corp.
 *                <benh@kernel.crashing.org>
 *
 * Based on the arch/ppc version of the driver:
 *
 * Copyright 2004 MontaVista Software, Inc.
 * Matt Porter <mporter@kernel.crashing.org>
 *
 * Copyright (c) 2005 Eugene Surovegin <ebs@ebshome.net>
 */
#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"

int tah_attach(struct platform_device *ofdev, int channel)
{
        struct tah_instance *dev = platform_get_drvdata(ofdev);

        mutex_lock(&dev->lock);
        /* Reset has been done at probe() time... nothing else to do for now */
        ++dev->users;
        mutex_unlock(&dev->lock);

        return 0;
}

void tah_detach(struct platform_device *ofdev, int channel)
{
        struct tah_instance *dev = platform_get_drvdata(ofdev);

        mutex_lock(&dev->lock);
        --dev->users;
        mutex_unlock(&dev->lock);
}

void tah_reset(struct platform_device *ofdev)
{
        struct tah_instance *dev = platform_get_drvdata(ofdev);
        struct tah_regs __iomem *p = dev->base;
        int n;

        /* Reset TAH */
        out_be32(&p->mr, TAH_MR_SR);
        n = 100;
        while ((in_be32(&p->mr) & TAH_MR_SR) && n)
                --n;

        if (unlikely(!n))
                printk(KERN_ERR "%pOF: reset timeout\n", ofdev->dev.of_node);

        /* 10KB TAH TX FIFO accommodates the max MTU of 9000 */
        out_be32(&p->mr,
                 TAH_MR_CVR | TAH_MR_ST_768 | TAH_MR_TFS_10KB | TAH_MR_DTFP |
                 TAH_MR_DIG);
}

int tah_get_regs_len(struct platform_device *ofdev)
{
        return sizeof(struct emac_ethtool_regs_subhdr) +
                sizeof(struct tah_regs);
}

void *tah_dump_regs(struct platform_device *ofdev, void *buf)
{
        struct tah_instance *dev = platform_get_drvdata(ofdev);
        struct emac_ethtool_regs_subhdr *hdr = buf;
        struct tah_regs *regs = (struct tah_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 tah_regs));
        return regs + 1;
}

static int tah_probe(struct platform_device *ofdev)
{
        struct tah_instance *dev;
        int err;

        dev = devm_kzalloc(&ofdev->dev, sizeof(struct tah_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);
        }

        platform_set_drvdata(ofdev, dev);

        /* Initialize TAH and enable IPv4 checksum verification, no TSO yet */
        tah_reset(ofdev);

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

        return 0;
}

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

static struct platform_driver tah_driver = {
        .driver = {
                .name = "emac-tah",
                .of_match_table = tah_match,
        },
        .probe = tah_probe,
};

int __init tah_init(void)
{
        return platform_driver_register(&tah_driver);
}

void tah_exit(void)
{
        platform_driver_unregister(&tah_driver);
}