// SPDX-License-Identifier: GPL-2.0-only
/*
 * pata_opti.c  - ATI PATA for new ATA layer
 *                        (C) 2005 Red Hat Inc
 *
 * Based on
 *  linux/drivers/ide/pci/opti621.c             Version 0.7     Sept 10, 2002
 *
 *  Copyright (C) 1996-1998  Linus Torvalds & authors (see below)
 *
 * Authors:
 * Jaromir Koutek <miri@punknet.cz>,
 * Jan Harkes <jaharkes@cwi.nl>,
 * Mark Lord <mlord@pobox.com>
 * Some parts of code are from ali14xx.c and from rz1000.c.
 *
 * Also consulted the FreeBSD prototype driver by Kevin Day to try
 * and resolve some confusions. Further documentation can be found in
 * Ralf Brown's interrupt list
 *
 * If you have other variants of the Opti range (Viper/Vendetta) please
 * try this driver with those PCI idents and report back. For the later
 * chips see the pata_optidma driver
 *
 */

#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_opti"
#define DRV_VERSION "0.2.9"

enum {
        READ_REG        = 0,    /* index of Read cycle timing register */
        WRITE_REG       = 1,    /* index of Write cycle timing register */
        CNTRL_REG       = 3,    /* index of Control register */
        STRAP_REG       = 5,    /* index of Strap register */
        MISC_REG        = 6     /* index of Miscellaneous register */
};

/**
 *      opti_pre_reset          -       probe begin
 *      @link: ATA link
 *      @deadline: deadline jiffies for the operation
 *
 *      Set up cable type and use generic probe init
 */

static int opti_pre_reset(struct ata_link *link, unsigned long deadline)
{
        struct ata_port *ap = link->ap;
        struct pci_dev *pdev = to_pci_dev(ap->host->dev);
        static const struct pci_bits opti_enable_bits[] = {
                { 0x45, 1, 0x80, 0x00 },
                { 0x40, 1, 0x08, 0x00 }
        };

        if (!pci_test_config_bits(pdev, &opti_enable_bits[ap->port_no]))
                return -ENOENT;

        return ata_sff_prereset(link, deadline);
}

/**
 *      opti_write_reg          -       control register setup
 *      @ap: ATA port
 *      @val: value
 *      @reg: control register number
 *
 *      The Opti uses magic 'trapdoor' register accesses to do configuration
 *      rather than using PCI space as other controllers do. The double inw
 *      on the error register activates configuration mode. We can then write
 *      the control register
 */

static void opti_write_reg(struct ata_port *ap, u8 val, int reg)
{
        void __iomem *regio = ap->ioaddr.cmd_addr;

        /* These 3 unlock the control register access */
        ioread16(regio + 1);
        ioread16(regio + 1);
        iowrite8(3, regio + 2);

        /* Do the I/O */
        iowrite8(val, regio + reg);

        /* Relock */
        iowrite8(0x83, regio + 2);
}

/**
 *      opti_set_piomode        -       set initial PIO mode data
 *      @ap: ATA interface
 *      @adev: ATA device
 *
 *      Called to do the PIO mode setup. Timing numbers are taken from
 *      the FreeBSD driver then pre computed to keep the code clean. There
 *      are two tables depending on the hardware clock speed.
 */

static void opti_set_piomode(struct ata_port *ap, struct ata_device *adev)
{
        struct ata_device *pair = ata_dev_pair(adev);
        int clock;
        int pio = adev->pio_mode - XFER_PIO_0;
        void __iomem *regio = ap->ioaddr.cmd_addr;
        u8 addr;

        /* Address table precomputed with prefetch off and a DCLK of 2 */
        static const u8 addr_timing[2][5] = {
                { 0x30, 0x20, 0x20, 0x10, 0x10 },
                { 0x20, 0x20, 0x10, 0x10, 0x10 }
        };
        static const u8 data_rec_timing[2][5] = {
                { 0x6B, 0x56, 0x42, 0x32, 0x31 },
                { 0x58, 0x44, 0x32, 0x22, 0x21 }
        };

        iowrite8(0xff, regio + 5);
        clock = ioread16(regio + 5) & 1;

        /*
         *      As with many controllers the address setup time is shared
         *      and must suit both devices if present.
         */

        addr = addr_timing[clock][pio];
        if (pair) {
                /* Hardware constraint */
                u8 pair_addr = addr_timing[clock][pair->pio_mode - XFER_PIO_0];
                if (pair_addr > addr)
                        addr = pair_addr;
        }

        /* Commence primary programming sequence */
        opti_write_reg(ap, adev->devno, MISC_REG);
        opti_write_reg(ap, data_rec_timing[clock][pio], READ_REG);
        opti_write_reg(ap, data_rec_timing[clock][pio], WRITE_REG);
        opti_write_reg(ap, addr, MISC_REG);

        /* Programming sequence complete, override strapping */
        opti_write_reg(ap, 0x85, CNTRL_REG);
}

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

static struct ata_port_operations opti_port_ops = {
        .inherits       = &ata_sff_port_ops,
        .cable_detect   = ata_cable_40wire,
        .set_piomode    = opti_set_piomode,
        .reset.prereset = opti_pre_reset,
};

static int opti_init_one(struct pci_dev *dev, const struct pci_device_id *id)
{
        static const struct ata_port_info info = {
                .flags = ATA_FLAG_SLAVE_POSS,
                .pio_mask = ATA_PIO4,
                .port_ops = &opti_port_ops
        };
        const struct ata_port_info *ppi[] = { &info, NULL };

        ata_print_version_once(&dev->dev, DRV_VERSION);

        return ata_pci_sff_init_one(dev, ppi, &opti_sht, NULL, 0);
}

static const struct pci_device_id opti[] = {
        { PCI_VDEVICE(OPTI, PCI_DEVICE_ID_OPTI_82C621), 0 },
        { PCI_VDEVICE(OPTI, PCI_DEVICE_ID_OPTI_82C825), 1 },

        { },
};

static struct pci_driver opti_pci_driver = {
        .name           = DRV_NAME,
        .id_table       = opti,
        .probe          = opti_init_one,
        .remove         = ata_pci_remove_one,
#ifdef CONFIG_PM_SLEEP
        .suspend        = ata_pci_device_suspend,
        .resume         = ata_pci_device_resume,
#endif
};

module_pci_driver(opti_pci_driver);

MODULE_AUTHOR("Alan Cox");
MODULE_DESCRIPTION("low-level driver for Opti 621/621X");
MODULE_LICENSE("GPL");
MODULE_DEVICE_TABLE(pci, opti);
MODULE_VERSION(DRV_VERSION);