// 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);