/*
 * Copyright (C) 2002 Toshiba Corporation
 * Copyright (C) 2005-2006 MontaVista Software, Inc. <source@mvista.com>
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2.  This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#include <linux/types.h>
#include <linux/pci.h>
#include <linux/ide.h>
#include <linux/module.h>

#define DRV_NAME "tc86c001"

static void tc86c001_set_mode(ide_hwif_t *hwif, ide_drive_t *drive)
{
        unsigned long scr_port  = hwif->config_data + (drive->dn ? 0x02 : 0x00);
        u16 mode, scr           = inw(scr_port);
        const u8 speed          = drive->dma_mode;

        switch (speed) {
        case XFER_UDMA_4:       mode = 0x00c0; break;
        case XFER_UDMA_3:       mode = 0x00b0; break;
        case XFER_UDMA_2:       mode = 0x00a0; break;
        case XFER_UDMA_1:       mode = 0x0090; break;
        case XFER_UDMA_0:       mode = 0x0080; break;
        case XFER_MW_DMA_2:     mode = 0x0070; break;
        case XFER_MW_DMA_1:     mode = 0x0060; break;
        case XFER_MW_DMA_0:     mode = 0x0050; break;
        case XFER_PIO_4:        mode = 0x0400; break;
        case XFER_PIO_3:        mode = 0x0300; break;
        case XFER_PIO_2:        mode = 0x0200; break;
        case XFER_PIO_1:        mode = 0x0100; break;
        case XFER_PIO_0:
        default:                mode = 0x0000; break;
        }

        scr &= (speed < XFER_MW_DMA_0) ? 0xf8ff : 0xff0f;
        scr |= mode;
        outw(scr, scr_port);
}

static void tc86c001_set_pio_mode(ide_hwif_t *hwif, ide_drive_t *drive)
{
        drive->dma_mode = drive->pio_mode;
        tc86c001_set_mode(hwif, drive);
}

/*
 * HACKITY HACK
 *
 * This is a workaround for the limitation 5 of the TC86C001 IDE controller:
 * if a DMA transfer terminates prematurely, the controller leaves the device's
 * interrupt request (INTRQ) pending and does not generate a PCI interrupt (or
 * set the interrupt bit in the DMA status register), thus no PCI interrupt
 * will occur until a DMA transfer has been successfully completed.
 *
 * We work around this by initiating dummy, zero-length DMA transfer on
 * a DMA timeout expiration. I found no better way to do this with the current
 * IDE core than to temporarily replace a higher level driver's timer expiry
 * handler with our own backing up to that handler in case our recovery fails.
 */
static int tc86c001_timer_expiry(ide_drive_t *drive)
{
        ide_hwif_t *hwif        = drive->hwif;
        ide_expiry_t *expiry    = ide_get_hwifdata(hwif);
        u8 dma_stat             = inb(hwif->dma_base + ATA_DMA_STATUS);

        /* Restore a higher level driver's expiry handler first. */
        hwif->expiry = expiry;

        if ((dma_stat & 5) == 1) {      /* DMA active and no interrupt */
                unsigned long sc_base   = hwif->config_data;
                unsigned long twcr_port = sc_base + (drive->dn ? 0x06 : 0x04);
                u8 dma_cmd              = inb(hwif->dma_base + ATA_DMA_CMD);

                printk(KERN_WARNING "%s: DMA interrupt possibly stuck, "
                       "attempting recovery...\n", drive->name);

                /* Stop DMA */
                outb(dma_cmd & ~0x01, hwif->dma_base + ATA_DMA_CMD);

                /* Setup the dummy DMA transfer */
                outw(0, sc_base + 0x0a);        /* Sector Count */
                outw(0, twcr_port);     /* Transfer Word Count 1 or 2 */

                /* Start the dummy DMA transfer */

                /* clear R_OR_WCTR for write */
                outb(0x00, hwif->dma_base + ATA_DMA_CMD);
                /* set START_STOPBM */
                outb(0x01, hwif->dma_base + ATA_DMA_CMD);

                /*
                 * If an interrupt was pending, it should come thru shortly.
                 * If not, a higher level driver's expiry handler should
                 * eventually cause some kind of recovery from the DMA stall.
                 */
                return WAIT_MIN_SLEEP;
        }

        /* Chain to the restored expiry handler if DMA wasn't active. */
        if (likely(expiry != NULL))
                return expiry(drive);

        /* If there was no handler, "emulate" that for ide_timer_expiry()... */
        return -1;
}

static void tc86c001_dma_start(ide_drive_t *drive)
{
        ide_hwif_t *hwif        = drive->hwif;
        unsigned long sc_base   = hwif->config_data;
        unsigned long twcr_port = sc_base + (drive->dn ? 0x06 : 0x04);
        unsigned long nsectors  = blk_rq_sectors(hwif->rq);

        /*
         * We have to manually load the sector count and size into
         * the appropriate system control registers for DMA to work
         * with LBA48 and ATAPI devices...
         */
        outw(nsectors, sc_base + 0x0a); /* Sector Count */
        outw(SECTOR_SIZE / 2, twcr_port); /* Transfer Word Count 1/2 */

        /* Install our timeout expiry hook, saving the current handler... */
        ide_set_hwifdata(hwif, hwif->expiry);
        hwif->expiry = &tc86c001_timer_expiry;

        ide_dma_start(drive);
}

static u8 tc86c001_cable_detect(ide_hwif_t *hwif)
{
        struct pci_dev *dev = to_pci_dev(hwif->dev);
        unsigned long sc_base = pci_resource_start(dev, 5);
        u16 scr1 = inw(sc_base + 0x00);

        /*
         * System Control  1 Register bit 13 (PDIAGN):
         * 0=80-pin cable, 1=40-pin cable
         */
        return (scr1 & 0x2000) ? ATA_CBL_PATA40 : ATA_CBL_PATA80;
}

static void init_hwif_tc86c001(ide_hwif_t *hwif)
{
        struct pci_dev *dev     = to_pci_dev(hwif->dev);
        unsigned long sc_base   = pci_resource_start(dev, 5);
        u16 scr1                = inw(sc_base + 0x00);

        /* System Control 1 Register bit 15 (Soft Reset) set */
        outw(scr1 |  0x8000, sc_base + 0x00);

        /* System Control 1 Register bit 14 (FIFO Reset) set */
        outw(scr1 |  0x4000, sc_base + 0x00);

        /* System Control 1 Register: reset clear */
        outw(scr1 & ~0xc000, sc_base + 0x00);

        /* Store the system control register base for convenience... */
        hwif->config_data = sc_base;

        if (!hwif->dma_base)
                return;

        /*
         * Sector Count Control Register bits 0 and 1 set:
         * software sets Sector Count Register for master and slave device
         */
        outw(0x0003, sc_base + 0x0c);

        /* Sector Count Register limit */
        hwif->rqsize     = 0xffff;
}

static const struct ide_port_ops tc86c001_port_ops = {
        .set_pio_mode           = tc86c001_set_pio_mode,
        .set_dma_mode           = tc86c001_set_mode,
        .cable_detect           = tc86c001_cable_detect,
};

static const struct ide_dma_ops tc86c001_dma_ops = {
        .dma_host_set           = ide_dma_host_set,
        .dma_setup              = ide_dma_setup,
        .dma_start              = tc86c001_dma_start,
        .dma_end                = ide_dma_end,
        .dma_test_irq           = ide_dma_test_irq,
        .dma_lost_irq           = ide_dma_lost_irq,
        .dma_timer_expiry       = ide_dma_sff_timer_expiry,
        .dma_sff_read_status    = ide_dma_sff_read_status,
};

static const struct ide_port_info tc86c001_chipset = {
        .name           = DRV_NAME,
        .init_hwif      = init_hwif_tc86c001,
        .port_ops       = &tc86c001_port_ops,
        .dma_ops        = &tc86c001_dma_ops,
        .host_flags     = IDE_HFLAG_SINGLE | IDE_HFLAG_OFF_BOARD,
        .pio_mask       = ATA_PIO4,
        .mwdma_mask     = ATA_MWDMA2,
        .udma_mask      = ATA_UDMA4,
};

static int tc86c001_init_one(struct pci_dev *dev,
                             const struct pci_device_id *id)
{
        int rc;

        rc = pci_enable_device(dev);
        if (rc)
                goto out;

        rc = pci_request_region(dev, 5, DRV_NAME);
        if (rc) {
                printk(KERN_ERR DRV_NAME ": system control regs already in use");
                goto out_disable;
        }

        rc = ide_pci_init_one(dev, &tc86c001_chipset, NULL);
        if (rc)
                goto out_release;

        goto out;

out_release:
        pci_release_region(dev, 5);
out_disable:
        pci_disable_device(dev);
out:
        return rc;
}

static void tc86c001_remove(struct pci_dev *dev)
{
        ide_pci_remove(dev);
        pci_release_region(dev, 5);
        pci_disable_device(dev);
}

static const struct pci_device_id tc86c001_pci_tbl[] = {
        { PCI_VDEVICE(TOSHIBA_2, PCI_DEVICE_ID_TOSHIBA_TC86C001_IDE), 0 },
        { 0, }
};
MODULE_DEVICE_TABLE(pci, tc86c001_pci_tbl);

static struct pci_driver tc86c001_pci_driver = {
        .name           = "TC86C001",
        .id_table       = tc86c001_pci_tbl,
        .probe          = tc86c001_init_one,
        .remove         = tc86c001_remove,
};

static int __init tc86c001_ide_init(void)
{
        return ide_pci_register_driver(&tc86c001_pci_driver);
}

static void __exit tc86c001_ide_exit(void)
{
        pci_unregister_driver(&tc86c001_pci_driver);
}

module_init(tc86c001_ide_init);
module_exit(tc86c001_ide_exit);

MODULE_AUTHOR("MontaVista Software, Inc. <source@mvista.com>");
MODULE_DESCRIPTION("PCI driver module for TC86C001 IDE");
MODULE_LICENSE("GPL");