[PATCH] ata_piix: convert pata to new reset mechanism

[linux-2.6/suspend2-2.6.18.git] / drivers / scsi / ata_piix.c

/*
 *    ata_piix.c - Intel PATA/SATA controllers
 *
 *    Maintained by:  Jeff Garzik <jgarzik@pobox.com>
 *                  Please ALWAYS copy linux-ide@vger.kernel.org
 *                  on emails.
 *
 *
 *      Copyright 2003-2005 Red Hat Inc
 *      Copyright 2003-2005 Jeff Garzik
 *
 *
 *      Copyright header from piix.c:
 *
 *  Copyright (C) 1998-1999 Andrzej Krzysztofowicz, Author and Maintainer
 *  Copyright (C) 1998-2000 Andre Hedrick <andre@linux-ide.org>
 *  Copyright (C) 2003 Red Hat Inc <alan@redhat.com>
 *
 *
 *  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.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; see the file COPYING.  If not, write to
 *  the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 *
 *  libata documentation is available via 'make {ps|pdf}docs',
 *  as Documentation/DocBook/libata.*
 *
 *  Hardware documentation available at http://developer.intel.com/
 *
 * Documentation
 *      Publically available from Intel web site. Errata documentation
 * is also publically available. As an aide to anyone hacking on this
 * driver the list of errata that are relevant is below.going back to
 * PIIX4. Older device documentation is now a bit tricky to find.
 *
 * The chipsets all follow very much the same design. The orginal Triton
 * series chipsets do _not_ support independant device timings, but this
 * is fixed in Triton II. With the odd mobile exception the chips then
 * change little except in gaining more modes until SATA arrives. This
 * driver supports only the chips with independant timing (that is those
 * with SITRE and the 0x44 timing register). See pata_oldpiix and pata_mpiix
 * for the early chip drivers.
 *
 * Errata of note:
 *
 * Unfixable
 *      PIIX4    errata #9      - Only on ultra obscure hw
 *      ICH3     errata #13     - Not observed to affect real hw
 *                                by Intel
 *
 * Things we must deal with
 *      PIIX4   errata #10      - BM IDE hang with non UDMA
 *                                (must stop/start dma to recover)
 *      440MX   errata #15      - As PIIX4 errata #10
 *      PIIX4   errata #15      - Must not read control registers
 *                                during a PIO transfer
 *      440MX   errata #13      - As PIIX4 errata #15
 *      ICH2    errata #21      - DMA mode 0 doesn't work right
 *      ICH0/1  errata #55      - As ICH2 errata #21
 *      ICH2    spec c #9       - Extra operations needed to handle
 *                                drive hotswap [NOT YET SUPPORTED]
 *      ICH2    spec c #20      - IDE PRD must not cross a 64K boundary
 *                                and must be dword aligned
 *      ICH2    spec c #24      - UDMA mode 4,5 t85/86 should be 6ns not 3.3
 *
 * Should have been BIOS fixed:
 *      450NX:  errata #19      - DMA hangs on old 450NX
 *      450NX:  errata #20      - DMA hangs on old 450NX
 *      450NX:  errata #25      - Corruption with DMA on old 450NX
 *      ICH3    errata #15      - IDE deadlock under high load
 *                                (BIOS must set dev 31 fn 0 bit 23)
 *      ICH3    errata #18      - Don't use native mode
 */

#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>

#define DRV_NAME        "ata_piix"
#define DRV_VERSION     "1.05"

enum {
        PIIX_IOCFG              = 0x54, /* IDE I/O configuration register */
        ICH5_PMR                = 0x90, /* port mapping register */
        ICH5_PCS                = 0x92, /* port control and status */
        PIIX_SCC                = 0x0A, /* sub-class code register */

        PIIX_FLAG_AHCI          = (1 << 27), /* AHCI possible */
        PIIX_FLAG_CHECKINTR     = (1 << 28), /* make sure PCI INTx enabled */
        PIIX_FLAG_COMBINED      = (1 << 29), /* combined mode possible */
        /* ICH6/7 use different scheme for map value */
        PIIX_FLAG_COMBINED_ICH6 = PIIX_FLAG_COMBINED | (1 << 30),

        /* combined mode.  if set, PATA is channel 0.
         * if clear, PATA is channel 1.
         */
        PIIX_COMB_PATA_P0       = (1 << 1),
        PIIX_COMB               = (1 << 2), /* combined mode enabled? */

        PIIX_PORT_ENABLED       = (1 << 0),
        PIIX_PORT_PRESENT       = (1 << 4),

        PIIX_80C_PRI            = (1 << 5) | (1 << 4),
        PIIX_80C_SEC            = (1 << 7) | (1 << 6),

        ich5_pata               = 0,
        ich5_sata               = 1,
        piix4_pata              = 2,
        ich6_sata               = 3,
        ich6_sata_ahci          = 4,

        PIIX_AHCI_DEVICE        = 6,
};

static int piix_init_one (struct pci_dev *pdev,
                                    const struct pci_device_id *ent);

static int piix_pata_probe_reset(struct ata_port *ap, unsigned int *classes);
static void piix_sata_phy_reset(struct ata_port *ap);
static void piix_set_piomode (struct ata_port *ap, struct ata_device *adev);
static void piix_set_dmamode (struct ata_port *ap, struct ata_device *adev);

static unsigned int in_module_init = 1;

static const struct pci_device_id piix_pci_tbl[] = {
#ifdef ATA_ENABLE_PATA
        { 0x8086, 0x7111, PCI_ANY_ID, PCI_ANY_ID, 0, 0, piix4_pata },
        { 0x8086, 0x24db, PCI_ANY_ID, PCI_ANY_ID, 0, 0, ich5_pata },
        { 0x8086, 0x25a2, PCI_ANY_ID, PCI_ANY_ID, 0, 0, ich5_pata },
#endif

        /* NOTE: The following PCI ids must be kept in sync with the
         * list in drivers/pci/quirks.c.
         */

        { 0x8086, 0x24d1, PCI_ANY_ID, PCI_ANY_ID, 0, 0, ich5_sata },
        { 0x8086, 0x24df, PCI_ANY_ID, PCI_ANY_ID, 0, 0, ich5_sata },
        { 0x8086, 0x25a3, PCI_ANY_ID, PCI_ANY_ID, 0, 0, ich5_sata },
        { 0x8086, 0x25b0, PCI_ANY_ID, PCI_ANY_ID, 0, 0, ich5_sata },
        { 0x8086, 0x2651, PCI_ANY_ID, PCI_ANY_ID, 0, 0, ich6_sata },
        { 0x8086, 0x2652, PCI_ANY_ID, PCI_ANY_ID, 0, 0, ich6_sata_ahci },
        { 0x8086, 0x2653, PCI_ANY_ID, PCI_ANY_ID, 0, 0, ich6_sata_ahci },
        { 0x8086, 0x27c0, PCI_ANY_ID, PCI_ANY_ID, 0, 0, ich6_sata_ahci },
        { 0x8086, 0x27c4, PCI_ANY_ID, PCI_ANY_ID, 0, 0, ich6_sata_ahci },
        { 0x8086, 0x2680, PCI_ANY_ID, PCI_ANY_ID, 0, 0, ich6_sata_ahci },
        { 0x8086, 0x2820, PCI_ANY_ID, PCI_ANY_ID, 0, 0, ich6_sata_ahci },
        { 0x8086, 0x2825, PCI_ANY_ID, PCI_ANY_ID, 0, 0, ich6_sata_ahci },
        { 0x8086, 0x2828, PCI_ANY_ID, PCI_ANY_ID, 0, 0, ich6_sata_ahci },

        { }     /* terminate list */
};

static struct pci_driver piix_pci_driver = {
        .name                   = DRV_NAME,
        .id_table               = piix_pci_tbl,
        .probe                  = piix_init_one,
        .remove                 = ata_pci_remove_one,
        .suspend                = ata_pci_device_suspend,
        .resume                 = ata_pci_device_resume,
};

static struct scsi_host_template piix_sht = {
        .module                 = THIS_MODULE,
        .name                   = DRV_NAME,
        .ioctl                  = ata_scsi_ioctl,
        .queuecommand           = ata_scsi_queuecmd,
        .eh_timed_out           = ata_scsi_timed_out,
        .eh_strategy_handler    = ata_scsi_error,
        .can_queue              = ATA_DEF_QUEUE,
        .this_id                = ATA_SHT_THIS_ID,
        .sg_tablesize           = LIBATA_MAX_PRD,
        .cmd_per_lun            = ATA_SHT_CMD_PER_LUN,
        .emulated               = ATA_SHT_EMULATED,
        .use_clustering         = ATA_SHT_USE_CLUSTERING,
        .proc_name              = DRV_NAME,
        .dma_boundary           = ATA_DMA_BOUNDARY,
        .slave_configure        = ata_scsi_slave_config,
        .bios_param             = ata_std_bios_param,
        .resume                 = ata_scsi_device_resume,
        .suspend                = ata_scsi_device_suspend,
};

static const struct ata_port_operations piix_pata_ops = {
        .port_disable           = ata_port_disable,
        .set_piomode            = piix_set_piomode,
        .set_dmamode            = piix_set_dmamode,

        .tf_load                = ata_tf_load,
        .tf_read                = ata_tf_read,
        .check_status           = ata_check_status,
        .exec_command           = ata_exec_command,
        .dev_select             = ata_std_dev_select,

        .probe_reset            = piix_pata_probe_reset,

        .bmdma_setup            = ata_bmdma_setup,
        .bmdma_start            = ata_bmdma_start,
        .bmdma_stop             = ata_bmdma_stop,
        .bmdma_status           = ata_bmdma_status,
        .qc_prep                = ata_qc_prep,
        .qc_issue               = ata_qc_issue_prot,

        .eng_timeout            = ata_eng_timeout,

        .irq_handler            = ata_interrupt,
        .irq_clear              = ata_bmdma_irq_clear,

        .port_start             = ata_port_start,
        .port_stop              = ata_port_stop,
        .host_stop              = ata_host_stop,
};

static const struct ata_port_operations piix_sata_ops = {
        .port_disable           = ata_port_disable,

        .tf_load                = ata_tf_load,
        .tf_read                = ata_tf_read,
        .check_status           = ata_check_status,
        .exec_command           = ata_exec_command,
        .dev_select             = ata_std_dev_select,

        .phy_reset              = piix_sata_phy_reset,

        .bmdma_setup            = ata_bmdma_setup,
        .bmdma_start            = ata_bmdma_start,
        .bmdma_stop             = ata_bmdma_stop,
        .bmdma_status           = ata_bmdma_status,
        .qc_prep                = ata_qc_prep,
        .qc_issue               = ata_qc_issue_prot,

        .eng_timeout            = ata_eng_timeout,

        .irq_handler            = ata_interrupt,
        .irq_clear              = ata_bmdma_irq_clear,

        .port_start             = ata_port_start,
        .port_stop              = ata_port_stop,
        .host_stop              = ata_host_stop,
};

static struct ata_port_info piix_port_info[] = {
        /* ich5_pata */
        {
                .sht            = &piix_sht,
                .host_flags     = ATA_FLAG_SLAVE_POSS | PIIX_FLAG_CHECKINTR,
                .pio_mask       = 0x1f, /* pio0-4 */
#if 0
                .mwdma_mask     = 0x06, /* mwdma1-2 */
#else
                .mwdma_mask     = 0x00, /* mwdma broken */
#endif
                .udma_mask      = 0x3f, /* udma0-5 */
                .port_ops       = &piix_pata_ops,
        },

        /* ich5_sata */
        {
                .sht            = &piix_sht,
                .host_flags     = ATA_FLAG_SATA | ATA_FLAG_SRST |
                                  PIIX_FLAG_COMBINED | PIIX_FLAG_CHECKINTR,
                .pio_mask       = 0x1f, /* pio0-4 */
                .mwdma_mask     = 0x07, /* mwdma0-2 */
                .udma_mask      = 0x7f, /* udma0-6 */
                .port_ops       = &piix_sata_ops,
        },

        /* piix4_pata */
        {
                .sht            = &piix_sht,
                .host_flags     = ATA_FLAG_SLAVE_POSS,
                .pio_mask       = 0x1f, /* pio0-4 */
#if 0
                .mwdma_mask     = 0x06, /* mwdma1-2 */
#else
                .mwdma_mask     = 0x00, /* mwdma broken */
#endif
                .udma_mask      = ATA_UDMA_MASK_40C,
                .port_ops       = &piix_pata_ops,
        },

        /* ich6_sata */
        {
                .sht            = &piix_sht,
                .host_flags     = ATA_FLAG_SATA | ATA_FLAG_SRST |
                                  PIIX_FLAG_COMBINED_ICH6 |
                                  PIIX_FLAG_CHECKINTR | ATA_FLAG_SLAVE_POSS,
                .pio_mask       = 0x1f, /* pio0-4 */
                .mwdma_mask     = 0x07, /* mwdma0-2 */
                .udma_mask      = 0x7f, /* udma0-6 */
                .port_ops       = &piix_sata_ops,
        },

        /* ich6_sata_ahci */
        {
                .sht            = &piix_sht,
                .host_flags     = ATA_FLAG_SATA | ATA_FLAG_SRST |
                                  PIIX_FLAG_COMBINED_ICH6 |
                                  PIIX_FLAG_CHECKINTR | ATA_FLAG_SLAVE_POSS |
                                  PIIX_FLAG_AHCI,
                .pio_mask       = 0x1f, /* pio0-4 */
                .mwdma_mask     = 0x07, /* mwdma0-2 */
                .udma_mask      = 0x7f, /* udma0-6 */
                .port_ops       = &piix_sata_ops,
        },
};

static struct pci_bits piix_enable_bits[] = {
        { 0x41U, 1U, 0x80UL, 0x80UL },  /* port 0 */
        { 0x43U, 1U, 0x80UL, 0x80UL },  /* port 1 */
};

MODULE_AUTHOR("Andre Hedrick, Alan Cox, Andrzej Krzysztofowicz, Jeff Garzik");
MODULE_DESCRIPTION("SCSI low-level driver for Intel PIIX/ICH ATA controllers");
MODULE_LICENSE("GPL");
MODULE_DEVICE_TABLE(pci, piix_pci_tbl);
MODULE_VERSION(DRV_VERSION);

/**
 *      piix_pata_cbl_detect - Probe host controller cable detect info
 *      @ap: Port for which cable detect info is desired
 *
 *      Read 80c cable indicator from ATA PCI device's PCI config
 *      register.  This register is normally set by firmware (BIOS).
 *
 *      LOCKING:
 *      None (inherited from caller).
 */
static void piix_pata_cbl_detect(struct ata_port *ap)
{
        struct pci_dev *pdev = to_pci_dev(ap->host_set->dev);
        u8 tmp, mask;

        /* no 80c support in host controller? */
        if ((ap->udma_mask & ~ATA_UDMA_MASK_40C) == 0)
                goto cbl40;

        /* check BIOS cable detect results */
        mask = ap->hard_port_no == 0 ? PIIX_80C_PRI : PIIX_80C_SEC;
        pci_read_config_byte(pdev, PIIX_IOCFG, &tmp);
        if ((tmp & mask) == 0)
                goto cbl40;

        ap->cbl = ATA_CBL_PATA80;
        return;

cbl40:
        ap->cbl = ATA_CBL_PATA40;
        ap->udma_mask &= ATA_UDMA_MASK_40C;
}

/**
 *      piix_pata_probeinit - probeinit for PATA host controller
 *      @ap: Target port
 *
 *      Probeinit including cable detection.
 *
 *      LOCKING:
 *      None (inherited from caller).
 */
static void piix_pata_probeinit(struct ata_port *ap)
{
        piix_pata_cbl_detect(ap);
        ata_std_probeinit(ap);
}

/**
 *      piix_pata_probe_reset - Perform reset on PATA port and classify
 *      @ap: Port to reset
 *      @classes: Resulting classes of attached devices
 *
 *      Reset PATA phy and classify attached devices.
 *
 *      LOCKING:
 *      None (inherited from caller).
 */
static int piix_pata_probe_reset(struct ata_port *ap, unsigned int *classes)
{
        struct pci_dev *pdev = to_pci_dev(ap->host_set->dev);

        if (!pci_test_config_bits(pdev, &piix_enable_bits[ap->hard_port_no])) {
                printk(KERN_INFO "ata%u: port disabled. ignoring.\n", ap->id);
                return 0;
        }

        return ata_drive_probe_reset(ap, piix_pata_probeinit,
                                     ata_std_softreset, NULL,
                                     ata_std_postreset, classes);
}

/**
 *      piix_sata_probe - Probe PCI device for present SATA devices
 *      @ap: Port associated with the PCI device we wish to probe
 *
 *      Reads SATA PCI device's PCI config register Port Configuration
 *      and Status (PCS) to determine port and device availability.
 *
 *      LOCKING:
 *      None (inherited from caller).
 *
 *      RETURNS:
 *      Non-zero if port is enabled, it may or may not have a device
 *      attached in that case (PRESENT bit would only be set if BIOS probe
 *      was done). Zero is returned if port is disabled.
 */
static int piix_sata_probe (struct ata_port *ap)
{
        struct pci_dev *pdev = to_pci_dev(ap->host_set->dev);
        int combined = (ap->flags & ATA_FLAG_SLAVE_POSS);
        int orig_mask, mask, i;
        u8 pcs;

        pci_read_config_byte(pdev, ICH5_PCS, &pcs);
        orig_mask = (int) pcs & 0xff;

        /* TODO: this is vaguely wrong for ICH6 combined mode,
         * where only two of the four SATA ports are mapped
         * onto a single ATA channel.  It is also vaguely inaccurate
         * for ICH5, which has only two ports.  However, this is ok,
         * as further device presence detection code will handle
         * any false positives produced here.
         */

        for (i = 0; i < 4; i++) {
                mask = (PIIX_PORT_ENABLED << i);

                if ((orig_mask & mask) == mask)
                        if (combined || (i == ap->hard_port_no))
                                return 1;
        }

        return 0;
}

/**
 *      piix_sata_phy_reset - Probe specified port on SATA host controller
 *      @ap: Port to probe
 *
 *      Probe SATA phy.
 *
 *      LOCKING:
 *      None (inherited from caller).
 */

static void piix_sata_phy_reset(struct ata_port *ap)
{
        if (!piix_sata_probe(ap)) {
                ata_port_disable(ap);
                printk(KERN_INFO "ata%u: SATA port has no device.\n", ap->id);
                return;
        }

        ap->cbl = ATA_CBL_SATA;

        ata_port_probe(ap);

        ata_bus_reset(ap);
}

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

static void piix_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_set->dev);
        unsigned int is_slave   = (adev->devno != 0);
        unsigned int master_port= ap->hard_port_no ? 0x42 : 0x40;
        unsigned int slave_port = 0x44;
        u16 master_data;
        u8 slave_data;

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

        pci_read_config_word(dev, master_port, &master_data);
        if (is_slave) {
                master_data |= 0x4000;
                /* enable PPE, IE and TIME */
                master_data |= 0x0070;
                pci_read_config_byte(dev, slave_port, &slave_data);
                slave_data &= (ap->hard_port_no ? 0x0f : 0xf0);
                slave_data |=
                        (timings[pio][0] << 2) |
                        (timings[pio][1] << (ap->hard_port_no ? 4 : 0));
        } else {
                master_data &= 0xccf8;
                /* enable PPE, IE and TIME */
                master_data |= 0x0007;
                master_data |=
                        (timings[pio][0] << 12) |
                        (timings[pio][1] << 8);
        }
        pci_write_config_word(dev, master_port, master_data);
        if (is_slave)
                pci_write_config_byte(dev, slave_port, slave_data);
}

/**
 *      piix_set_dmamode - Initialize host controller PATA PIO timings
 *      @ap: Port whose timings we are configuring
 *      @adev: um
 *      @udma: udma mode, 0 - 6
 *
 *      Set UDMA mode for device, in host controller PCI config space.
 *
 *      LOCKING:
 *      None (inherited from caller).
 */

static void piix_set_dmamode (struct ata_port *ap, struct ata_device *adev)
{
        unsigned int udma       = adev->dma_mode; /* FIXME: MWDMA too */
        struct pci_dev *dev     = to_pci_dev(ap->host_set->dev);
        u8 maslave              = ap->hard_port_no ? 0x42 : 0x40;
        u8 speed                = udma;
        unsigned int drive_dn   = (ap->hard_port_no ? 2 : 0) + adev->devno;
        int a_speed             = 3 << (drive_dn * 4);
        int u_flag              = 1 << drive_dn;
        int v_flag              = 0x01 << drive_dn;
        int w_flag              = 0x10 << drive_dn;
        int u_speed             = 0;
        int                     sitre;
        u16                     reg4042, reg4a;
        u8                      reg48, reg54, reg55;

        pci_read_config_word(dev, maslave, &reg4042);
        DPRINTK("reg4042 = 0x%04x\n", reg4042);
        sitre = (reg4042 & 0x4000) ? 1 : 0;
        pci_read_config_byte(dev, 0x48, &reg48);
        pci_read_config_word(dev, 0x4a, &reg4a);
        pci_read_config_byte(dev, 0x54, &reg54);
        pci_read_config_byte(dev, 0x55, &reg55);

        switch(speed) {
                case XFER_UDMA_4:
                case XFER_UDMA_2:       u_speed = 2 << (drive_dn * 4); break;
                case XFER_UDMA_6:
                case XFER_UDMA_5:
                case XFER_UDMA_3:
                case XFER_UDMA_1:       u_speed = 1 << (drive_dn * 4); break;
                case XFER_UDMA_0:       u_speed = 0 << (drive_dn * 4); break;
                case XFER_MW_DMA_2:
                case XFER_MW_DMA_1:     break;
                default:
                        BUG();
                        return;
        }

        if (speed >= XFER_UDMA_0) {
                if (!(reg48 & u_flag))
                        pci_write_config_byte(dev, 0x48, reg48 | u_flag);
                if (speed == XFER_UDMA_5) {
                        pci_write_config_byte(dev, 0x55, (u8) reg55|w_flag);
                } else {
                        pci_write_config_byte(dev, 0x55, (u8) reg55 & ~w_flag);
                }
                if ((reg4a & a_speed) != u_speed)
                        pci_write_config_word(dev, 0x4a, (reg4a & ~a_speed) | u_speed);
                if (speed > XFER_UDMA_2) {
                        if (!(reg54 & v_flag))
                                pci_write_config_byte(dev, 0x54, reg54 | v_flag);
                } else
                        pci_write_config_byte(dev, 0x54, reg54 & ~v_flag);
        } else {
                if (reg48 & u_flag)
                        pci_write_config_byte(dev, 0x48, reg48 & ~u_flag);
                if (reg4a & a_speed)
                        pci_write_config_word(dev, 0x4a, reg4a & ~a_speed);
                if (reg54 & v_flag)
                        pci_write_config_byte(dev, 0x54, reg54 & ~v_flag);
                if (reg55 & w_flag)
                        pci_write_config_byte(dev, 0x55, (u8) reg55 & ~w_flag);
        }
}

#define AHCI_PCI_BAR 5
#define AHCI_GLOBAL_CTL 0x04
#define AHCI_ENABLE (1 << 31)
static int piix_disable_ahci(struct pci_dev *pdev)
{
        void __iomem *mmio;
        u32 tmp;
        int rc = 0;

        /* BUG: pci_enable_device has not yet been called.  This
         * works because this device is usually set up by BIOS.
         */

        if (!pci_resource_start(pdev, AHCI_PCI_BAR) ||
            !pci_resource_len(pdev, AHCI_PCI_BAR))
                return 0;

        mmio = pci_iomap(pdev, AHCI_PCI_BAR, 64);
        if (!mmio)
                return -ENOMEM;

        tmp = readl(mmio + AHCI_GLOBAL_CTL);
        if (tmp & AHCI_ENABLE) {
                tmp &= ~AHCI_ENABLE;
                writel(tmp, mmio + AHCI_GLOBAL_CTL);

                tmp = readl(mmio + AHCI_GLOBAL_CTL);
                if (tmp & AHCI_ENABLE)
                        rc = -EIO;
        }

        pci_iounmap(pdev, mmio);
        return rc;
}

/**
 *      piix_check_450nx_errata -       Check for problem 450NX setup
 *      @ata_dev: the PCI device to check
 *      
 *      Check for the present of 450NX errata #19 and errata #25. If
 *      they are found return an error code so we can turn off DMA
 */

static int __devinit piix_check_450nx_errata(struct pci_dev *ata_dev)
{
        struct pci_dev *pdev = NULL;
        u16 cfg;
        u8 rev;
        int no_piix_dma = 0;
        
        while((pdev = pci_get_device(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82454NX, pdev)) != NULL)
        {
                /* Look for 450NX PXB. Check for problem configurations
                   A PCI quirk checks bit 6 already */
                pci_read_config_byte(pdev, PCI_REVISION_ID, &rev);
                pci_read_config_word(pdev, 0x41, &cfg);
                /* Only on the original revision: IDE DMA can hang */
                if(rev == 0x00)
                        no_piix_dma = 1;
                /* On all revisions below 5 PXB bus lock must be disabled for IDE */
                else if(cfg & (1<<14) && rev < 5)
                        no_piix_dma = 2;
        }
        if(no_piix_dma)
                dev_printk(KERN_WARNING, &ata_dev->dev, "450NX errata present, disabling IDE DMA.\n");
        if(no_piix_dma == 2)
                dev_printk(KERN_WARNING, &ata_dev->dev, "A BIOS update may resolve this.\n");
        return no_piix_dma;
}               

/**
 *      piix_init_one - Register PIIX ATA PCI device with kernel services
 *      @pdev: PCI device to register
 *      @ent: Entry in piix_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 piix_init_one (struct pci_dev *pdev, const struct pci_device_id *ent)
{
        static int printed_version;
        struct ata_port_info *port_info[2];
        unsigned int combined = 0;
        unsigned int pata_chan = 0, sata_chan = 0;
        unsigned long host_flags;

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

        /* no hotplugging support (FIXME) */
        if (!in_module_init)
                return -ENODEV;

        port_info[0] = &piix_port_info[ent->driver_data];
        port_info[1] = &piix_port_info[ent->driver_data];

        host_flags = port_info[0]->host_flags;

        if (host_flags & PIIX_FLAG_AHCI) {
                u8 tmp;
                pci_read_config_byte(pdev, PIIX_SCC, &tmp);
                if (tmp == PIIX_AHCI_DEVICE) {
                        int rc = piix_disable_ahci(pdev);
                        if (rc)
                                return rc;
                }
        }

        if (host_flags & PIIX_FLAG_COMBINED) {
                u8 tmp;
                pci_read_config_byte(pdev, ICH5_PMR, &tmp);

                if (host_flags & PIIX_FLAG_COMBINED_ICH6) {
                        switch (tmp & 0x3) {
                        case 0:
                                break;
                        case 1:
                                combined = 1;
                                sata_chan = 1;
                                break;
                        case 2:
                                combined = 1;
                                pata_chan = 1;
                                break;
                        case 3:
                                dev_printk(KERN_WARNING, &pdev->dev,
                                           "invalid MAP value %u\n", tmp);
                                break;
                        }
                } else {
                        if (tmp & PIIX_COMB) {
                                combined = 1;
                                if (tmp & PIIX_COMB_PATA_P0)
                                        sata_chan = 1;
                                else
                                        pata_chan = 1;
                        }
                }
        }

        /* On ICH5, some BIOSen disable the interrupt using the
         * PCI_COMMAND_INTX_DISABLE bit added in PCI 2.3.
         * On ICH6, this bit has the same effect, but only when
         * MSI is disabled (and it is disabled, as we don't use
         * message-signalled interrupts currently).
         */
        if (host_flags & PIIX_FLAG_CHECKINTR)
                pci_intx(pdev, 1);

        if (combined) {
                port_info[sata_chan] = &piix_port_info[ent->driver_data];
                port_info[sata_chan]->host_flags |= ATA_FLAG_SLAVE_POSS;
                port_info[pata_chan] = &piix_port_info[ich5_pata];

                dev_printk(KERN_WARNING, &pdev->dev,
                           "combined mode detected (p=%u, s=%u)\n",
                           pata_chan, sata_chan);
        }
        if (piix_check_450nx_errata(pdev)) {
                /* This writes into the master table but it does not
                   really matter for this errata as we will apply it to
                   all the PIIX devices on the board */
                port_info[0]->mwdma_mask = 0;
                port_info[0]->udma_mask = 0;
                port_info[1]->mwdma_mask = 0;
                port_info[1]->udma_mask = 0;
        }
        return ata_pci_init_one(pdev, port_info, 2);
}

static int __init piix_init(void)
{
        int rc;

        DPRINTK("pci_module_init\n");
        rc = pci_module_init(&piix_pci_driver);
        if (rc)
                return rc;

        in_module_init = 0;

        DPRINTK("done\n");
        return 0;
}

static void __exit piix_exit(void)
{
        pci_unregister_driver(&piix_pci_driver);
}

module_init(piix_init);
module_exit(piix_exit);