// SPDX-License-Identifier: GPL-2.0-only
/*
 *  RZ1000/1001 driver based upon
 *
 *  linux/drivers/ide/pci/rz1000.c	Version 0.06	January 12, 2003
 *  Copyright (C) 1995-1998  Linus Torvalds & author (see below)
 *  Principal Author:  mlord@pobox.com (Mark Lord)
 *
 *  See linux/MAINTAINERS for address of current maintainer.
 *
 *  This file provides support for disabling the buggy read-ahead
 *  mode of the RZ1000 IDE chipset, commonly used on Intel motherboards.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/blkdev.h>
#include <linux/delay.h>
#include <scsi/scsi_host.h>
#include <linux/libata.h>

#define DRV_NAME	"pata_rz1000"
#define DRV_VERSION	"0.2.4"


/**
 *	rz1000_set_mode		-	mode setting function
 *	@link: ATA link
 *	@unused: returned device on set_mode failure
 *
 *	Use a non standard set_mode function. We don't want to be tuned. We
 *	would prefer to be BIOS generic but for the fact our hardware is
 *	whacked out.
 */

static int rz1000_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 = XFER_PIO_0;
		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 const struct scsi_host_template rz1000_sht = {
	ATA_PIO_SHT(DRV_NAME),
};

static struct ata_port_operations rz1000_port_ops = {
	.inherits	= &ata_sff_port_ops,
	.cable_detect	= ata_cable_40wire,
	.set_mode	= rz1000_set_mode,
};

static int rz1000_fifo_disable(struct pci_dev *pdev)
{
	u16 reg;
	/* Be exceptionally paranoid as we must be sure to apply the fix */
	if (pci_read_config_word(pdev, 0x40, &reg) != 0)
		return -1;
	reg &= 0xDFFF;
	if (pci_write_config_word(pdev, 0x40, reg) != 0)
		return -1;
	dev_info(&pdev->dev, "disabled chipset readahead.\n");
	return 0;
}

/**
 *	rz1000_init_one - Register RZ1000 ATA PCI device with kernel services
 *	@pdev: PCI device to register
 *	@ent: Entry in rz1000_pci_tbl matching with @pdev
 *
 *	Configure an RZ1000 interface. This doesn't require much special
 *	handling except that we *MUST* kill the chipset readahead or the
 *	user may experience data corruption.
 */

static int rz1000_init_one (struct pci_dev *pdev, const struct pci_device_id *ent)
{
	static const struct ata_port_info info = {
		.flags = ATA_FLAG_SLAVE_POSS,
		.pio_mask = ATA_PIO4,
		.port_ops = &rz1000_port_ops
	};
	const struct ata_port_info *ppi[] = { &info, NULL };

	ata_print_version_once(&pdev->dev, DRV_VERSION);

	if (rz1000_fifo_disable(pdev) == 0)
		return ata_pci_sff_init_one(pdev, ppi, &rz1000_sht, NULL, 0);

	dev_err(&pdev->dev, "failed to disable read-ahead on chipset.\n");
	/* Not safe to use so skip */
	return -ENODEV;
}

#ifdef CONFIG_PM_SLEEP
static int rz1000_reinit_one(struct pci_dev *pdev)
{
	struct ata_host *host = pci_get_drvdata(pdev);
	int rc;

	rc = ata_pci_device_do_resume(pdev);
	if (rc)
		return rc;

	/* If this fails on resume (which is a "can't happen" case), we
	   must stop as any progress risks data loss */
	if (rz1000_fifo_disable(pdev))
		panic("rz1000 fifo");

	ata_host_resume(host);
	return 0;
}
#endif

static const struct pci_device_id pata_rz1000[] = {
	{ PCI_VDEVICE(PCTECH, PCI_DEVICE_ID_PCTECH_RZ1000), },
	{ PCI_VDEVICE(PCTECH, PCI_DEVICE_ID_PCTECH_RZ1001), },

	{ },
};

static struct pci_driver rz1000_pci_driver = {
	.name 		= DRV_NAME,
	.id_table	= pata_rz1000,
	.probe 		= rz1000_init_one,
	.remove		= ata_pci_remove_one,
#ifdef CONFIG_PM_SLEEP
	.suspend	= ata_pci_device_suspend,
	.resume		= rz1000_reinit_one,
#endif
};

module_pci_driver(rz1000_pci_driver);

MODULE_AUTHOR("Alan Cox");
MODULE_DESCRIPTION("low-level driver for RZ1000 PCI ATA");
MODULE_LICENSE("GPL");
MODULE_DEVICE_TABLE(pci, pata_rz1000);
MODULE_VERSION(DRV_VERSION);