// 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_new = 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);