/*
 *      IDE tuning and bus mastering support for the CS5510/CS5520
 *      chipsets
 *
 *      The CS5510/CS5520 are slightly unusual devices. Unlike the 
 *      typical IDE controllers they do bus mastering with the drive in
 *      PIO mode and smarter silicon.
 *
 *      The practical upshot of this is that we must always tune the
 *      drive for the right PIO mode. We must also ignore all the blacklists
 *      and the drive bus mastering DMA information.
 *
 *      *** This driver is strictly experimental ***
 *
 *      (c) Copyright Red Hat Inc 2002
 * 
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2, or (at your option) any
 * later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * For the avoidance of doubt the "preferred form" of this code is one which
 * is in an open non patent encumbered format. Where cryptographic key signing
 * forms part of the process of creating an executable the information
 * including keys needed to generate an equivalently functional executable
 * are deemed to be part of the source code.
 *
 */
 
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/pci.h>
#include <linux/ide.h>
#include <linux/dma-mapping.h>

#define DRV_NAME "cs5520"

struct pio_clocks
{
        int address;
        int assert;
        int recovery;
};

static struct pio_clocks cs5520_pio_clocks[]={
        {3, 6, 11},
        {2, 5, 6},
        {1, 4, 3},
        {1, 3, 2},
        {1, 2, 1}
};

static void cs5520_set_pio_mode(ide_hwif_t *hwif, ide_drive_t *drive)
{
        struct pci_dev *pdev = to_pci_dev(hwif->dev);
        int controller = drive->dn > 1 ? 1 : 0;
        const u8 pio = drive->pio_mode - XFER_PIO_0;

        /* 8bit CAT/CRT - 8bit command timing for channel */
        pci_write_config_byte(pdev, 0x62 + controller, 
                (cs5520_pio_clocks[pio].recovery << 4) |
                (cs5520_pio_clocks[pio].assert));

        /* 0x64 - 16bit Primary, 0x68 - 16bit Secondary */

        /* FIXME: should these use address ? */
        /* Data read timing */
        pci_write_config_byte(pdev, 0x64 + 4*controller + (drive->dn&1),
                (cs5520_pio_clocks[pio].recovery << 4) |
                (cs5520_pio_clocks[pio].assert));
        /* Write command timing */
        pci_write_config_byte(pdev, 0x66 + 4*controller + (drive->dn&1),
                (cs5520_pio_clocks[pio].recovery << 4) |
                (cs5520_pio_clocks[pio].assert));
}

static void cs5520_set_dma_mode(ide_hwif_t *hwif, ide_drive_t *drive)
{
        printk(KERN_ERR "cs55x0: bad ide timing.\n");

        drive->pio_mode = XFER_PIO_0 + 0;
        cs5520_set_pio_mode(hwif, drive);
}

static const struct ide_port_ops cs5520_port_ops = {
        .set_pio_mode           = cs5520_set_pio_mode,
        .set_dma_mode           = cs5520_set_dma_mode,
};

static const struct ide_port_info cyrix_chipset = {
        .name           = DRV_NAME,
        .enablebits     = { { 0x60, 0x01, 0x01 }, { 0x60, 0x02, 0x02 } },
        .port_ops       = &cs5520_port_ops,
        .host_flags     = IDE_HFLAG_ISA_PORTS | IDE_HFLAG_CS5520,
        .pio_mask       = ATA_PIO4,
};

/*
 *      The 5510/5520 are a bit weird. They don't quite set up the way
 *      the PCI helper layer expects so we must do much of the set up 
 *      work longhand.
 */
 
static int cs5520_init_one(struct pci_dev *dev, const struct pci_device_id *id)
{
        const struct ide_port_info *d = &cyrix_chipset;
        struct ide_hw hw[2], *hws[] = { NULL, NULL };

        ide_setup_pci_noise(dev, d);

        /* We must not grab the entire device, it has 'ISA' space in its
         * BARS too and we will freak out other bits of the kernel
         */
        if (pci_enable_device_io(dev)) {
                printk(KERN_WARNING "%s: Unable to enable 55x0.\n", d->name);
                return -ENODEV;
        }
        pci_set_master(dev);
        if (pci_set_dma_mask(dev, DMA_BIT_MASK(32))) {
                printk(KERN_WARNING "%s: No suitable DMA available.\n",
                        d->name);
                return -ENODEV;
        }

        /*
         *      Now the chipset is configured we can let the core
         *      do all the device setup for us
         */

        ide_pci_setup_ports(dev, d, &hw[0], &hws[0]);
        hw[0].irq = 14;
        hw[1].irq = 15;

        return ide_host_add(d, hws, 2, NULL);
}

static const struct pci_device_id cs5520_pci_tbl[] = {
        { PCI_VDEVICE(CYRIX, PCI_DEVICE_ID_CYRIX_5510), 0 },
        { PCI_VDEVICE(CYRIX, PCI_DEVICE_ID_CYRIX_5520), 1 },
        { 0, },
};
MODULE_DEVICE_TABLE(pci, cs5520_pci_tbl);

static struct pci_driver cs5520_pci_driver = {
        .name           = "Cyrix_IDE",
        .id_table       = cs5520_pci_tbl,
        .probe          = cs5520_init_one,
        .suspend        = ide_pci_suspend,
        .resume         = ide_pci_resume,
};

static int __init cs5520_ide_init(void)
{
        return ide_pci_register_driver(&cs5520_pci_driver);
}

module_init(cs5520_ide_init);

MODULE_AUTHOR("Alan Cox");
MODULE_DESCRIPTION("PCI driver module for Cyrix 5510/5520 IDE");
MODULE_LICENSE("GPL");