/*
 *      ACPI PATA driver
 *
 *      (c) 2007 Red Hat
 */

#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 <linux/gfp.h>
#include <scsi/scsi_host.h>
#include <acpi/acpi_bus.h>

#include <linux/libata.h>
#include <linux/ata.h>

#define DRV_NAME        "pata_acpi"
#define DRV_VERSION     "0.2.3"

struct pata_acpi {
        struct ata_acpi_gtm gtm;
        void *last;
        unsigned long mask[2];
};

/**
 *      pacpi_pre_reset -       check for 40/80 pin
 *      @ap: Port
 *      @deadline: deadline jiffies for the operation
 *
 *      Perform the PATA port setup we need.
 */

static int pacpi_pre_reset(struct ata_link *link, unsigned long deadline)
{
        struct ata_port *ap = link->ap;
        struct pata_acpi *acpi = ap->private_data;
        if (ap->acpi_handle == NULL || ata_acpi_gtm(ap, &acpi->gtm) < 0)
                return -ENODEV;

        return ata_sff_prereset(link, deadline);
}

/**
 *      pacpi_cable_detect      -       cable type detection
 *      @ap: port to detect
 *
 *      Perform device specific cable detection
 */

static int pacpi_cable_detect(struct ata_port *ap)
{
        struct pata_acpi *acpi = ap->private_data;

        if ((acpi->mask[0] | acpi->mask[1]) & (0xF8 << ATA_SHIFT_UDMA))
                return ATA_CBL_PATA80;
        else
                return ATA_CBL_PATA40;
}

/**
 *      pacpi_discover_modes    -       filter non ACPI modes
 *      @adev: ATA device
 *      @mask: proposed modes
 *
 *      Try the modes available and see which ones the ACPI method will
 *      set up sensibly. From this we get a mask of ACPI modes we can use
 */

static unsigned long pacpi_discover_modes(struct ata_port *ap, struct ata_device *adev)
{
        struct pata_acpi *acpi = ap->private_data;
        struct ata_acpi_gtm probe;
        unsigned int xfer_mask;

        probe = acpi->gtm;

        ata_acpi_gtm(ap, &probe);

        xfer_mask = ata_acpi_gtm_xfermask(adev, &probe);

        if (xfer_mask & (0xF8 << ATA_SHIFT_UDMA))
                ap->cbl = ATA_CBL_PATA80;

        return xfer_mask;
}

/**
 *      pacpi_mode_filter       -       mode filter for ACPI
 *      @adev: device
 *      @mask: mask of valid modes
 *
 *      Filter the valid mode list according to our own specific rules, in
 *      this case the list of discovered valid modes obtained by ACPI probing
 */

static unsigned long pacpi_mode_filter(struct ata_device *adev, unsigned long mask)
{
        struct pata_acpi *acpi = adev->link->ap->private_data;
        return mask & acpi->mask[adev->devno];
}

/**
 *      pacpi_set_piomode       -       set initial PIO mode data
 *      @ap: ATA interface
 *      @adev: ATA device
 */

static void pacpi_set_piomode(struct ata_port *ap, struct ata_device *adev)
{
        int unit = adev->devno;
        struct pata_acpi *acpi = ap->private_data;
        const struct ata_timing *t;

        if (!(acpi->gtm.flags & 0x10))
                unit = 0;

        /* Now stuff the nS values into the structure */
        t = ata_timing_find_mode(adev->pio_mode);
        acpi->gtm.drive[unit].pio = t->cycle;
        ata_acpi_stm(ap, &acpi->gtm);
        /* See what mode we actually got */
        ata_acpi_gtm(ap, &acpi->gtm);
}

/**
 *      pacpi_set_dmamode       -       set initial DMA mode data
 *      @ap: ATA interface
 *      @adev: ATA device
 */

static void pacpi_set_dmamode(struct ata_port *ap, struct ata_device *adev)
{
        int unit = adev->devno;
        struct pata_acpi *acpi = ap->private_data;
        const struct ata_timing *t;

        if (!(acpi->gtm.flags & 0x10))
                unit = 0;

        /* Now stuff the nS values into the structure */
        t = ata_timing_find_mode(adev->dma_mode);
        if (adev->dma_mode >= XFER_UDMA_0) {
                acpi->gtm.drive[unit].dma = t->udma;
                acpi->gtm.flags |= (1 << (2 * unit));
        } else {
                acpi->gtm.drive[unit].dma = t->cycle;
                acpi->gtm.flags &= ~(1 << (2 * unit));
        }
        ata_acpi_stm(ap, &acpi->gtm);
        /* See what mode we actually got */
        ata_acpi_gtm(ap, &acpi->gtm);
}

/**
 *      pacpi_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.
 */

static unsigned int pacpi_qc_issue(struct ata_queued_cmd *qc)
{
        struct ata_port *ap = qc->ap;
        struct ata_device *adev = qc->dev;
        struct pata_acpi *acpi = ap->private_data;

        if (acpi->gtm.flags & 0x10)
                return ata_bmdma_qc_issue(qc);

        if (adev != acpi->last) {
                pacpi_set_piomode(ap, adev);
                if (ata_dma_enabled(adev))
                        pacpi_set_dmamode(ap, adev);
                acpi->last = adev;
        }
        return ata_bmdma_qc_issue(qc);
}

/**
 *      pacpi_port_start        -       port setup
 *      @ap: ATA port being set up
 *
 *      Use the port_start hook to maintain private control structures
 */

static int pacpi_port_start(struct ata_port *ap)
{
        struct pci_dev *pdev = to_pci_dev(ap->host->dev);
        struct pata_acpi *acpi;

        int ret;

        if (ap->acpi_handle == NULL)
                return -ENODEV;

        acpi = ap->private_data = devm_kzalloc(&pdev->dev, sizeof(struct pata_acpi), GFP_KERNEL);
        if (ap->private_data == NULL)
                return -ENOMEM;
        acpi->mask[0] = pacpi_discover_modes(ap, &ap->link.device[0]);
        acpi->mask[1] = pacpi_discover_modes(ap, &ap->link.device[1]);
        ret = ata_bmdma_port_start(ap);
        if (ret < 0)
                return ret;

        return ret;
}

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

static struct ata_port_operations pacpi_ops = {
        .inherits               = &ata_bmdma_port_ops,
        .qc_issue               = pacpi_qc_issue,
        .cable_detect           = pacpi_cable_detect,
        .mode_filter            = pacpi_mode_filter,
        .set_piomode            = pacpi_set_piomode,
        .set_dmamode            = pacpi_set_dmamode,
        .prereset               = pacpi_pre_reset,
        .port_start             = pacpi_port_start,
};


/**
 *      pacpi_init_one - Register ACPI ATA PCI device with kernel services
 *      @pdev: PCI device to register
 *      @ent: Entry in pacpi_pci_tbl matching with @pdev
 *
 *      Called from kernel PCI layer.
 *
 *      LOCKING:
 *      Inherited from PCI layer (may sleep).
 *
 *      RETURNS:
 *      Zero on success, or -ERRNO value.
 */

static int pacpi_init_one (struct pci_dev *pdev, const struct pci_device_id *id)
{
        static const struct ata_port_info info = {
                .flags          = ATA_FLAG_SLAVE_POSS | ATA_FLAG_SRST,

                .pio_mask       = ATA_PIO4,
                .mwdma_mask     = ATA_MWDMA2,
                .udma_mask      = ATA_UDMA6,

                .port_ops       = &pacpi_ops,
        };
        const struct ata_port_info *ppi[] = { &info, NULL };
        if (pdev->vendor == PCI_VENDOR_ID_ATI) {
                int rc = pcim_enable_device(pdev);
                if (rc < 0)
                        return rc;
                pcim_pin_device(pdev);
        }
        return ata_pci_bmdma_init_one(pdev, ppi, &pacpi_sht, NULL, 0);
}

static const struct pci_device_id pacpi_pci_tbl[] = {
        { PCI_ANY_ID,           PCI_ANY_ID,                        PCI_ANY_ID, PCI_ANY_ID, PCI_CLASS_STORAGE_IDE << 8, 0xFFFFFF00UL, 1},
        { }     /* terminate list */
};

static struct pci_driver pacpi_pci_driver = {
        .name                   = DRV_NAME,
        .id_table               = pacpi_pci_tbl,
        .probe                  = pacpi_init_one,
        .remove                 = ata_pci_remove_one,
#ifdef CONFIG_PM
        .suspend                = ata_pci_device_suspend,
        .resume                 = ata_pci_device_resume,
#endif
};

static int __init pacpi_init(void)
{
        return pci_register_driver(&pacpi_pci_driver);
}

static void __exit pacpi_exit(void)
{
        pci_unregister_driver(&pacpi_pci_driver);
}

module_init(pacpi_init);
module_exit(pacpi_exit);

MODULE_AUTHOR("Alan Cox");
MODULE_DESCRIPTION("SCSI low-level driver for ATA in ACPI mode");
MODULE_LICENSE("GPL");
MODULE_DEVICE_TABLE(pci, pacpi_pci_tbl);
MODULE_VERSION(DRV_VERSION);