// SPDX-License-Identifier: GPL-2.0

/*
 * Amiga Gayle PATA controller driver
 *
 * Copyright (c) 2018 Samsung Electronics Co., Ltd.
 *              http://www.samsung.com
 *
 * Based on gayle.c:
 *
 *     Created 12 Jul 1997 by Geert Uytterhoeven
 */

#include <linux/ata.h>
#include <linux/blkdev.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/libata.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/zorro.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_host.h>

#include <asm/amigahw.h>
#include <asm/amigaints.h>
#include <asm/amigayle.h>
#include <asm/setup.h>

#define DRV_NAME "pata_gayle"
#define DRV_VERSION "0.1.0"

#define GAYLE_CONTROL   0x101a

static const struct scsi_host_template pata_gayle_sht = {
        ATA_PIO_SHT(DRV_NAME),
};

/* FIXME: is this needed? */
static unsigned int pata_gayle_data_xfer(struct ata_queued_cmd *qc,
                                         unsigned char *buf,
                                         unsigned int buflen, int rw)
{
        struct ata_device *dev = qc->dev;
        struct ata_port *ap = dev->link->ap;
        void __iomem *data_addr = ap->ioaddr.data_addr;
        unsigned int words = buflen >> 1;

        /* Transfer multiple of 2 bytes */
        if (rw == READ)
                raw_insw((u16 *)data_addr, (u16 *)buf, words);
        else
                raw_outsw((u16 *)data_addr, (u16 *)buf, words);

        /* Transfer trailing byte, if any. */
        if (unlikely(buflen & 0x01)) {
                unsigned char pad[2] = { };

                /* Point buf to the tail of buffer */
                buf += buflen - 1;

                if (rw == READ) {
                        raw_insw((u16 *)data_addr, (u16 *)pad, 1);
                        *buf = pad[0];
                } else {
                        pad[0] = *buf;
                        raw_outsw((u16 *)data_addr, (u16 *)pad, 1);
                }
                words++;
        }

        return words << 1;
}

/*
 * Provide our own set_mode() as we don't want to change anything that has
 * already been configured..
 */
static int pata_gayle_set_mode(struct ata_link *link,
                               struct ata_device **unused)
{
        struct ata_device *dev;

        ata_for_each_dev(dev, link, ENABLED) {
                /* We don't really care */
                dev->pio_mode = dev->xfer_mode = XFER_PIO_0;
                dev->xfer_shift = ATA_SHIFT_PIO;
                dev->flags |= ATA_DFLAG_PIO;
                ata_dev_info(dev, "configured for PIO\n");
        }
        return 0;
}

static bool pata_gayle_irq_check(struct ata_port *ap)
{
        u8 ch;

        ch = z_readb((unsigned long)ap->private_data);

        return !!(ch & GAYLE_IRQ_IDE);
}

static void pata_gayle_irq_clear(struct ata_port *ap)
{
        (void)z_readb((unsigned long)ap->ioaddr.status_addr);
        z_writeb(0x7c, (unsigned long)ap->private_data);
}

static struct ata_port_operations pata_gayle_a1200_ops = {
        .inherits       = &ata_sff_port_ops,
        .sff_data_xfer  = pata_gayle_data_xfer,
        .sff_irq_check  = pata_gayle_irq_check,
        .sff_irq_clear  = pata_gayle_irq_clear,
        .cable_detect   = ata_cable_unknown,
        .set_mode       = pata_gayle_set_mode,
};

static struct ata_port_operations pata_gayle_a4000_ops = {
        .inherits       = &ata_sff_port_ops,
        .sff_data_xfer  = pata_gayle_data_xfer,
        .cable_detect   = ata_cable_unknown,
        .set_mode       = pata_gayle_set_mode,
};

static int pata_gayle_init_one(struct platform_device *pdev)
{
        struct resource *res;
        struct gayle_ide_platform_data *pdata;
        struct ata_host *host;
        struct ata_port *ap;
        void __iomem *base;
        int ret;

        pdata = dev_get_platdata(&pdev->dev);

        dev_info(&pdev->dev, "Amiga Gayle IDE controller (A%u style)\n",
                pdata->explicit_ack ? 1200 : 4000);

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!res)
                return -ENODEV;

        if (!devm_request_mem_region(&pdev->dev, res->start,
                                     resource_size(res), DRV_NAME)) {
                pr_err(DRV_NAME ": resources busy\n");
                return -EBUSY;
        }

        /* allocate host */
        host = ata_host_alloc(&pdev->dev, 1);
        if (!host)
                return -ENOMEM;

        ap = host->ports[0];

        if (pdata->explicit_ack)
                ap->ops = &pata_gayle_a1200_ops;
        else
                ap->ops = &pata_gayle_a4000_ops;

        ap->pio_mask = ATA_PIO4;
        ap->flags |= ATA_FLAG_SLAVE_POSS | ATA_FLAG_NO_IORDY;

        base = ZTWO_VADDR(pdata->base);
        ap->ioaddr.data_addr            = base;
        ap->ioaddr.error_addr           = base + 2 + 1 * 4;
        ap->ioaddr.feature_addr         = base + 2 + 1 * 4;
        ap->ioaddr.nsect_addr           = base + 2 + 2 * 4;
        ap->ioaddr.lbal_addr            = base + 2 + 3 * 4;
        ap->ioaddr.lbam_addr            = base + 2 + 4 * 4;
        ap->ioaddr.lbah_addr            = base + 2 + 5 * 4;
        ap->ioaddr.device_addr          = base + 2 + 6 * 4;
        ap->ioaddr.status_addr          = base + 2 + 7 * 4;
        ap->ioaddr.command_addr         = base + 2 + 7 * 4;

        ap->ioaddr.altstatus_addr       = base + GAYLE_CONTROL;
        ap->ioaddr.ctl_addr             = base + GAYLE_CONTROL;

        ap->private_data = (void *)ZTWO_VADDR(pdata->irqport);

        ata_port_desc(ap, "cmd 0x%lx ctl 0x%lx", pdata->base,
                      pdata->base + GAYLE_CONTROL);

        ret = ata_host_activate(host, IRQ_AMIGA_PORTS, ata_sff_interrupt,
                                IRQF_SHARED, &pata_gayle_sht);
        if (ret)
                return ret;

        platform_set_drvdata(pdev, host);

        return 0;
}

static void pata_gayle_remove_one(struct platform_device *pdev)
{
        struct ata_host *host = platform_get_drvdata(pdev);

        ata_host_detach(host);
}

static struct platform_driver pata_gayle_driver = {
        .probe = pata_gayle_init_one,
        .remove = pata_gayle_remove_one,
        .driver = {
                .name = "amiga-gayle-ide",
        },
};

module_platform_driver(pata_gayle_driver);

MODULE_AUTHOR("Bartlomiej Zolnierkiewicz");
MODULE_DESCRIPTION("low-level driver for Amiga Gayle PATA");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:amiga-gayle-ide");
MODULE_VERSION(DRV_VERSION);