/*
 *    pata_oldpiix.c - Intel PATA/SATA controllers
 *
 *      (C) 2005 Red Hat
 *
 *    Some parts based on ata_piix.c by Jeff Garzik and others.
 *
 *    Early PIIX differs significantly from the later PIIX as it lacks
 *    SITRE and the slave timing registers. This means that you have to
 *    set timing per channel, or be clever. Libata tells us whenever it
 *    does drive selection and we use this to reload the timings.
 *
 *    Because of these behaviour differences PIIX gets its own driver module.
 */

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

#define DRV_NAME        "pata_oldpiix"
#define DRV_VERSION     "0.5.5"

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

static int oldpiix_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 oldpiix_enable_bits[] = {
                { 0x41U, 1U, 0x80UL, 0x80UL },  /* port 0 */
                { 0x43U, 1U, 0x80UL, 0x80UL },  /* port 1 */
        };

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

        return ata_sff_prereset(link, deadline);
}

/**
 *      oldpiix_set_piomode - Initialize host controller PATA PIO timings
 *      @ap: Port whose timings we are configuring
 *      @adev: Device whose timings we are configuring
 *
 *      Set PIO mode for device, in host controller PCI config space.
 *
 *      LOCKING:
 *      None (inherited from caller).
 */

static void oldpiix_set_piomode (struct ata_port *ap, struct ata_device *adev)
{
        unsigned int pio        = adev->pio_mode - XFER_PIO_0;
        struct pci_dev *dev     = to_pci_dev(ap->host->dev);
        unsigned int idetm_port= ap->port_no ? 0x42 : 0x40;
        u16 idetm_data;
        int control = 0;

        /*
         *      See Intel Document 298600-004 for the timing programing rules
         *      for PIIX/ICH. Note that the early PIIX does not have the slave
         *      timing port at 0x44.
         */

        static const     /* ISP  RTC */
        u8 timings[][2] = { { 0, 0 },
                            { 0, 0 },
                            { 1, 0 },
                            { 2, 1 },
                            { 2, 3 }, };

        if (pio > 1)
                control |= 1;   /* TIME */
        if (ata_pio_need_iordy(adev))
                control |= 2;   /* IE */

        /* Intel specifies that the prefetch/posting is for disk only */
        if (adev->class == ATA_DEV_ATA)
                control |= 4;   /* PPE */

        pci_read_config_word(dev, idetm_port, &idetm_data);

        /*
         * Set PPE, IE and TIME as appropriate.
         * Clear the other drive's timing bits.
         */
        if (adev->devno == 0) {
                idetm_data &= 0xCCE0;
                idetm_data |= control;
        } else {
                idetm_data &= 0xCC0E;
                idetm_data |= (control << 4);
        }
        idetm_data |= (timings[pio][0] << 12) |
                        (timings[pio][1] << 8);
        pci_write_config_word(dev, idetm_port, idetm_data);

        /* Track which port is configured */
        ap->private_data = adev;
}

/**
 *      oldpiix_set_dmamode - Initialize host controller PATA DMA timings
 *      @ap: Port whose timings we are configuring
 *      @adev: Device to program
 *
 *      Set MWDMA mode for device, in host controller PCI config space.
 *
 *      LOCKING:
 *      None (inherited from caller).
 */

static void oldpiix_set_dmamode (struct ata_port *ap, struct ata_device *adev)
{
        struct pci_dev *dev     = to_pci_dev(ap->host->dev);
        u8 idetm_port           = ap->port_no ? 0x42 : 0x40;
        u16 idetm_data;

        static const     /* ISP  RTC */
        u8 timings[][2] = { { 0, 0 },
                            { 0, 0 },
                            { 1, 0 },
                            { 2, 1 },
                            { 2, 3 }, };

        /*
         * MWDMA is driven by the PIO timings. We must also enable
         * IORDY unconditionally along with TIME1. PPE has already
         * been set when the PIO timing was set.
         */

        unsigned int mwdma      = adev->dma_mode - XFER_MW_DMA_0;
        unsigned int control;
        const unsigned int needed_pio[3] = {
                XFER_PIO_0, XFER_PIO_3, XFER_PIO_4
        };
        int pio = needed_pio[mwdma] - XFER_PIO_0;

        pci_read_config_word(dev, idetm_port, &idetm_data);

        control = 3;    /* IORDY|TIME0 */
        /* Intel specifies that the PPE functionality is for disk only */
        if (adev->class == ATA_DEV_ATA)
                control |= 4;   /* PPE enable */

        /* If the drive MWDMA is faster than it can do PIO then
           we must force PIO into PIO0 */

        if (adev->pio_mode < needed_pio[mwdma])
                /* Enable DMA timing only */
                control |= 8;   /* PIO cycles in PIO0 */

        /* Mask out the relevant control and timing bits we will load. Also
           clear the other drive TIME register as a precaution */
        if (adev->devno == 0) {
                idetm_data &= 0xCCE0;
                idetm_data |= control;
        } else {
                idetm_data &= 0xCC0E;
                idetm_data |= (control << 4);
        }
        idetm_data |= (timings[pio][0] << 12) | (timings[pio][1] << 8);
        pci_write_config_word(dev, idetm_port, idetm_data);

        /* Track which port is configured */
        ap->private_data = adev;
}

/**
 *      oldpiix_qc_issue        -       command issue
 *      @qc: command pending
 *
 *      Called when the libata layer is about to issue a command. We wrap
 *      this interface so that we can load the correct ATA timings if
 *      necessary. Our logic also clears TIME0/TIME1 for the other device so
 *      that, even if we get this wrong, cycles to the other device will
 *      be made PIO0.
 */

static unsigned int oldpiix_qc_issue(struct ata_queued_cmd *qc)
{
        struct ata_port *ap = qc->ap;
        struct ata_device *adev = qc->dev;

        if (adev != ap->private_data) {
                oldpiix_set_piomode(ap, adev);
                if (ata_dma_enabled(adev))
                        oldpiix_set_dmamode(ap, adev);
        }
        return ata_bmdma_qc_issue(qc);
}


static struct scsi_host_template oldpiix_sht = {
        ATA_BMDMA_SHT(DRV_NAME),
};

static struct ata_port_operations oldpiix_pata_ops = {
        .inherits               = &ata_bmdma_port_ops,
        .qc_issue               = oldpiix_qc_issue,
        .cable_detect           = ata_cable_40wire,
        .set_piomode            = oldpiix_set_piomode,
        .set_dmamode            = oldpiix_set_dmamode,
        .prereset               = oldpiix_pre_reset,
};


/**
 *      oldpiix_init_one - Register PIIX ATA PCI device with kernel services
 *      @pdev: PCI device to register
 *      @ent: Entry in oldpiix_pci_tbl matching with @pdev
 *
 *      Called from kernel PCI layer.  We probe for combined mode (sigh),
 *      and then hand over control to libata, for it to do the rest.
 *
 *      LOCKING:
 *      Inherited from PCI layer (may sleep).
 *
 *      RETURNS:
 *      Zero on success, or -ERRNO value.
 */

static int oldpiix_init_one (struct pci_dev *pdev, const struct pci_device_id *ent)
{
        static int printed_version;
        static const struct ata_port_info info = {
                .flags          = ATA_FLAG_SLAVE_POSS,
                .pio_mask       = ATA_PIO4,
                .mwdma_mask     = ATA_MWDMA12_ONLY,
                .port_ops       = &oldpiix_pata_ops,
        };
        const struct ata_port_info *ppi[] = { &info, NULL };

        if (!printed_version++)
                dev_printk(KERN_DEBUG, &pdev->dev,
                           "version " DRV_VERSION "\n");

        return ata_pci_bmdma_init_one(pdev, ppi, &oldpiix_sht, NULL, 0);
}

static const struct pci_device_id oldpiix_pci_tbl[] = {
        { PCI_VDEVICE(INTEL, 0x1230), },

        { }     /* terminate list */
};

static struct pci_driver oldpiix_pci_driver = {
        .name                   = DRV_NAME,
        .id_table               = oldpiix_pci_tbl,
        .probe                  = oldpiix_init_one,
        .remove                 = ata_pci_remove_one,
#ifdef CONFIG_PM
        .suspend                = ata_pci_device_suspend,
        .resume                 = ata_pci_device_resume,
#endif
};

static int __init oldpiix_init(void)
{
        return pci_register_driver(&oldpiix_pci_driver);
}

static void __exit oldpiix_exit(void)
{
        pci_unregister_driver(&oldpiix_pci_driver);
}

module_init(oldpiix_init);
module_exit(oldpiix_exit);

MODULE_AUTHOR("Alan Cox");
MODULE_DESCRIPTION("SCSI low-level driver for early PIIX series controllers");
MODULE_LICENSE("GPL");
MODULE_DEVICE_TABLE(pci, oldpiix_pci_tbl);
MODULE_VERSION(DRV_VERSION);