RDMA/nes: Fix off-by-one

[linux-2.6/kvm.git] / drivers / ata / libata-sff.c

/*
 *  libata-sff.c - helper library for PCI IDE BMDMA
 *
 *  Maintained by:  Jeff Garzik <jgarzik@pobox.com>
 *                  Please ALWAYS copy linux-ide@vger.kernel.org
 *                  on emails.
 *
 *  Copyright 2003-2006 Red Hat, Inc.  All rights reserved.
 *  Copyright 2003-2006 Jeff Garzik
 *
 *
 *  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 from http://www.t13.org/ and
 *  http://www.sata-io.org/
 *
 */

#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/libata.h>

#include "libata.h"

/**
 *      ata_irq_on - Enable interrupts on a port.
 *      @ap: Port on which interrupts are enabled.
 *
 *      Enable interrupts on a legacy IDE device using MMIO or PIO,
 *      wait for idle, clear any pending interrupts.
 *
 *      LOCKING:
 *      Inherited from caller.
 */
u8 ata_irq_on(struct ata_port *ap)
{
        struct ata_ioports *ioaddr = &ap->ioaddr;
        u8 tmp;

        ap->ctl &= ~ATA_NIEN;
        ap->last_ctl = ap->ctl;

        iowrite8(ap->ctl, ioaddr->ctl_addr);
        tmp = ata_wait_idle(ap);

        ap->ops->irq_clear(ap);

        return tmp;
}

/**
 *      ata_tf_load - send taskfile registers to host controller
 *      @ap: Port to which output is sent
 *      @tf: ATA taskfile register set
 *
 *      Outputs ATA taskfile to standard ATA host controller.
 *
 *      LOCKING:
 *      Inherited from caller.
 */

void ata_tf_load(struct ata_port *ap, const struct ata_taskfile *tf)
{
        struct ata_ioports *ioaddr = &ap->ioaddr;
        unsigned int is_addr = tf->flags & ATA_TFLAG_ISADDR;

        if (tf->ctl != ap->last_ctl) {
                iowrite8(tf->ctl, ioaddr->ctl_addr);
                ap->last_ctl = tf->ctl;
                ata_wait_idle(ap);
        }

        if (is_addr && (tf->flags & ATA_TFLAG_LBA48)) {
                iowrite8(tf->hob_feature, ioaddr->feature_addr);
                iowrite8(tf->hob_nsect, ioaddr->nsect_addr);
                iowrite8(tf->hob_lbal, ioaddr->lbal_addr);
                iowrite8(tf->hob_lbam, ioaddr->lbam_addr);
                iowrite8(tf->hob_lbah, ioaddr->lbah_addr);
                VPRINTK("hob: feat 0x%X nsect 0x%X, lba 0x%X 0x%X 0x%X\n",
                        tf->hob_feature,
                        tf->hob_nsect,
                        tf->hob_lbal,
                        tf->hob_lbam,
                        tf->hob_lbah);
        }

        if (is_addr) {
                iowrite8(tf->feature, ioaddr->feature_addr);
                iowrite8(tf->nsect, ioaddr->nsect_addr);
                iowrite8(tf->lbal, ioaddr->lbal_addr);
                iowrite8(tf->lbam, ioaddr->lbam_addr);
                iowrite8(tf->lbah, ioaddr->lbah_addr);
                VPRINTK("feat 0x%X nsect 0x%X lba 0x%X 0x%X 0x%X\n",
                        tf->feature,
                        tf->nsect,
                        tf->lbal,
                        tf->lbam,
                        tf->lbah);
        }

        if (tf->flags & ATA_TFLAG_DEVICE) {
                iowrite8(tf->device, ioaddr->device_addr);
                VPRINTK("device 0x%X\n", tf->device);
        }

        ata_wait_idle(ap);
}

/**
 *      ata_exec_command - issue ATA command to host controller
 *      @ap: port to which command is being issued
 *      @tf: ATA taskfile register set
 *
 *      Issues ATA command, with proper synchronization with interrupt
 *      handler / other threads.
 *
 *      LOCKING:
 *      spin_lock_irqsave(host lock)
 */
void ata_exec_command(struct ata_port *ap, const struct ata_taskfile *tf)
{
        DPRINTK("ata%u: cmd 0x%X\n", ap->print_id, tf->command);

        iowrite8(tf->command, ap->ioaddr.command_addr);
        ata_pause(ap);
}

/**
 *      ata_tf_read - input device's ATA taskfile shadow registers
 *      @ap: Port from which input is read
 *      @tf: ATA taskfile register set for storing input
 *
 *      Reads ATA taskfile registers for currently-selected device
 *      into @tf. Assumes the device has a fully SFF compliant task file
 *      layout and behaviour. If you device does not (eg has a different
 *      status method) then you will need to provide a replacement tf_read
 *
 *      LOCKING:
 *      Inherited from caller.
 */
void ata_tf_read(struct ata_port *ap, struct ata_taskfile *tf)
{
        struct ata_ioports *ioaddr = &ap->ioaddr;

        tf->command = ata_check_status(ap);
        tf->feature = ioread8(ioaddr->error_addr);
        tf->nsect = ioread8(ioaddr->nsect_addr);
        tf->lbal = ioread8(ioaddr->lbal_addr);
        tf->lbam = ioread8(ioaddr->lbam_addr);
        tf->lbah = ioread8(ioaddr->lbah_addr);
        tf->device = ioread8(ioaddr->device_addr);

        if (tf->flags & ATA_TFLAG_LBA48) {
                iowrite8(tf->ctl | ATA_HOB, ioaddr->ctl_addr);
                tf->hob_feature = ioread8(ioaddr->error_addr);
                tf->hob_nsect = ioread8(ioaddr->nsect_addr);
                tf->hob_lbal = ioread8(ioaddr->lbal_addr);
                tf->hob_lbam = ioread8(ioaddr->lbam_addr);
                tf->hob_lbah = ioread8(ioaddr->lbah_addr);
                iowrite8(tf->ctl, ioaddr->ctl_addr);
                ap->last_ctl = tf->ctl;
        }
}

/**
 *      ata_check_status - Read device status reg & clear interrupt
 *      @ap: port where the device is
 *
 *      Reads ATA taskfile status register for currently-selected device
 *      and return its value. This also clears pending interrupts
 *      from this device
 *
 *      LOCKING:
 *      Inherited from caller.
 */
u8 ata_check_status(struct ata_port *ap)
{
        return ioread8(ap->ioaddr.status_addr);
}

/**
 *      ata_altstatus - Read device alternate status reg
 *      @ap: port where the device is
 *
 *      Reads ATA taskfile alternate status register for
 *      currently-selected device and return its value.
 *
 *      Note: may NOT be used as the check_altstatus() entry in
 *      ata_port_operations.
 *
 *      LOCKING:
 *      Inherited from caller.
 */
u8 ata_altstatus(struct ata_port *ap)
{
        if (ap->ops->check_altstatus)
                return ap->ops->check_altstatus(ap);

        return ioread8(ap->ioaddr.altstatus_addr);
}

/**
 *      ata_bmdma_setup - Set up PCI IDE BMDMA transaction
 *      @qc: Info associated with this ATA transaction.
 *
 *      LOCKING:
 *      spin_lock_irqsave(host lock)
 */
void ata_bmdma_setup(struct ata_queued_cmd *qc)
{
        struct ata_port *ap = qc->ap;
        unsigned int rw = (qc->tf.flags & ATA_TFLAG_WRITE);
        u8 dmactl;

        /* load PRD table addr. */
        mb();   /* make sure PRD table writes are visible to controller */
        iowrite32(ap->prd_dma, ap->ioaddr.bmdma_addr + ATA_DMA_TABLE_OFS);

        /* specify data direction, triple-check start bit is clear */
        dmactl = ioread8(ap->ioaddr.bmdma_addr + ATA_DMA_CMD);
        dmactl &= ~(ATA_DMA_WR | ATA_DMA_START);
        if (!rw)
                dmactl |= ATA_DMA_WR;
        iowrite8(dmactl, ap->ioaddr.bmdma_addr + ATA_DMA_CMD);

        /* issue r/w command */
        ap->ops->exec_command(ap, &qc->tf);
}

/**
 *      ata_bmdma_start - Start a PCI IDE BMDMA transaction
 *      @qc: Info associated with this ATA transaction.
 *
 *      LOCKING:
 *      spin_lock_irqsave(host lock)
 */
void ata_bmdma_start(struct ata_queued_cmd *qc)
{
        struct ata_port *ap = qc->ap;
        u8 dmactl;

        /* start host DMA transaction */
        dmactl = ioread8(ap->ioaddr.bmdma_addr + ATA_DMA_CMD);
        iowrite8(dmactl | ATA_DMA_START, ap->ioaddr.bmdma_addr + ATA_DMA_CMD);

        /* Strictly, one may wish to issue an ioread8() here, to
         * flush the mmio write.  However, control also passes
         * to the hardware at this point, and it will interrupt
         * us when we are to resume control.  So, in effect,
         * we don't care when the mmio write flushes.
         * Further, a read of the DMA status register _immediately_
         * following the write may not be what certain flaky hardware
         * is expected, so I think it is best to not add a readb()
         * without first all the MMIO ATA cards/mobos.
         * Or maybe I'm just being paranoid.
         *
         * FIXME: The posting of this write means I/O starts are
         * unneccessarily delayed for MMIO
         */
}

/**
 *      ata_bmdma_irq_clear - Clear PCI IDE BMDMA interrupt.
 *      @ap: Port associated with this ATA transaction.
 *
 *      Clear interrupt and error flags in DMA status register.
 *
 *      May be used as the irq_clear() entry in ata_port_operations.
 *
 *      LOCKING:
 *      spin_lock_irqsave(host lock)
 */
void ata_bmdma_irq_clear(struct ata_port *ap)
{
        void __iomem *mmio = ap->ioaddr.bmdma_addr;

        if (!mmio)
                return;

        iowrite8(ioread8(mmio + ATA_DMA_STATUS), mmio + ATA_DMA_STATUS);
}

/**
 *      ata_bmdma_status - Read PCI IDE BMDMA status
 *      @ap: Port associated with this ATA transaction.
 *
 *      Read and return BMDMA status register.
 *
 *      May be used as the bmdma_status() entry in ata_port_operations.
 *
 *      LOCKING:
 *      spin_lock_irqsave(host lock)
 */
u8 ata_bmdma_status(struct ata_port *ap)
{
        return ioread8(ap->ioaddr.bmdma_addr + ATA_DMA_STATUS);
}

/**
 *      ata_bmdma_stop - Stop PCI IDE BMDMA transfer
 *      @qc: Command we are ending DMA for
 *
 *      Clears the ATA_DMA_START flag in the dma control register
 *
 *      May be used as the bmdma_stop() entry in ata_port_operations.
 *
 *      LOCKING:
 *      spin_lock_irqsave(host lock)
 */
void ata_bmdma_stop(struct ata_queued_cmd *qc)
{
        struct ata_port *ap = qc->ap;
        void __iomem *mmio = ap->ioaddr.bmdma_addr;

        /* clear start/stop bit */
        iowrite8(ioread8(mmio + ATA_DMA_CMD) & ~ATA_DMA_START,
                 mmio + ATA_DMA_CMD);

        /* one-PIO-cycle guaranteed wait, per spec, for HDMA1:0 transition */
        ata_altstatus(ap);        /* dummy read */
}

/**
 *      ata_bmdma_freeze - Freeze BMDMA controller port
 *      @ap: port to freeze
 *
 *      Freeze BMDMA controller port.
 *
 *      LOCKING:
 *      Inherited from caller.
 */
void ata_bmdma_freeze(struct ata_port *ap)
{
        struct ata_ioports *ioaddr = &ap->ioaddr;

        ap->ctl |= ATA_NIEN;
        ap->last_ctl = ap->ctl;

        iowrite8(ap->ctl, ioaddr->ctl_addr);

        /* Under certain circumstances, some controllers raise IRQ on
         * ATA_NIEN manipulation.  Also, many controllers fail to mask
         * previously pending IRQ on ATA_NIEN assertion.  Clear it.
         */
        ata_chk_status(ap);

        ap->ops->irq_clear(ap);
}

/**
 *      ata_bmdma_thaw - Thaw BMDMA controller port
 *      @ap: port to thaw
 *
 *      Thaw BMDMA controller port.
 *
 *      LOCKING:
 *      Inherited from caller.
 */
void ata_bmdma_thaw(struct ata_port *ap)
{
        /* clear & re-enable interrupts */
        ata_chk_status(ap);
        ap->ops->irq_clear(ap);
        ap->ops->irq_on(ap);
}

/**
 *      ata_bmdma_drive_eh - Perform EH with given methods for BMDMA controller
 *      @ap: port to handle error for
 *      @prereset: prereset method (can be NULL)
 *      @softreset: softreset method (can be NULL)
 *      @hardreset: hardreset method (can be NULL)
 *      @postreset: postreset method (can be NULL)
 *
 *      Handle error for ATA BMDMA controller.  It can handle both
 *      PATA and SATA controllers.  Many controllers should be able to
 *      use this EH as-is or with some added handling before and
 *      after.
 *
 *      This function is intended to be used for constructing
 *      ->error_handler callback by low level drivers.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep)
 */
void ata_bmdma_drive_eh(struct ata_port *ap, ata_prereset_fn_t prereset,
                        ata_reset_fn_t softreset, ata_reset_fn_t hardreset,
                        ata_postreset_fn_t postreset)
{
        struct ata_queued_cmd *qc;
        unsigned long flags;
        int thaw = 0;

        qc = __ata_qc_from_tag(ap, ap->link.active_tag);
        if (qc && !(qc->flags & ATA_QCFLAG_FAILED))
                qc = NULL;

        /* reset PIO HSM and stop DMA engine */
        spin_lock_irqsave(ap->lock, flags);

        ap->hsm_task_state = HSM_ST_IDLE;

        if (qc && (qc->tf.protocol == ATA_PROT_DMA ||
                   qc->tf.protocol == ATAPI_PROT_DMA)) {
                u8 host_stat;

                host_stat = ap->ops->bmdma_status(ap);

                /* BMDMA controllers indicate host bus error by
                 * setting DMA_ERR bit and timing out.  As it wasn't
                 * really a timeout event, adjust error mask and
                 * cancel frozen state.
                 */
                if (qc->err_mask == AC_ERR_TIMEOUT && (host_stat & ATA_DMA_ERR)) {
                        qc->err_mask = AC_ERR_HOST_BUS;
                        thaw = 1;
                }

                ap->ops->bmdma_stop(qc);
        }

        ata_altstatus(ap);
        ata_chk_status(ap);
        ap->ops->irq_clear(ap);

        spin_unlock_irqrestore(ap->lock, flags);

        if (thaw)
                ata_eh_thaw_port(ap);

        /* PIO and DMA engines have been stopped, perform recovery */
        ata_do_eh(ap, prereset, softreset, hardreset, postreset);
}

/**
 *      ata_bmdma_error_handler - Stock error handler for BMDMA controller
 *      @ap: port to handle error for
 *
 *      Stock error handler for BMDMA controller.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep)
 */
void ata_bmdma_error_handler(struct ata_port *ap)
{
        ata_reset_fn_t hardreset;

        hardreset = NULL;
        if (sata_scr_valid(&ap->link))
                hardreset = sata_std_hardreset;

        ata_bmdma_drive_eh(ap, ata_std_prereset, ata_std_softreset, hardreset,
                           ata_std_postreset);
}

/**
 *      ata_bmdma_post_internal_cmd - Stock post_internal_cmd for
 *                                    BMDMA controller
 *      @qc: internal command to clean up
 *
 *      LOCKING:
 *      Kernel thread context (may sleep)
 */
void ata_bmdma_post_internal_cmd(struct ata_queued_cmd *qc)
{
        if (qc->ap->ioaddr.bmdma_addr)
                ata_bmdma_stop(qc);
}

/**
 *      ata_sff_port_start - Set port up for dma.
 *      @ap: Port to initialize
 *
 *      Called just after data structures for each port are
 *      initialized.  Allocates space for PRD table if the device
 *      is DMA capable SFF.
 *
 *      May be used as the port_start() entry in ata_port_operations.
 *
 *      LOCKING:
 *      Inherited from caller.
 */

int ata_sff_port_start(struct ata_port *ap)
{
        if (ap->ioaddr.bmdma_addr)
                return ata_port_start(ap);
        return 0;
}

#ifdef CONFIG_PCI

static int ata_resources_present(struct pci_dev *pdev, int port)
{
        int i;

        /* Check the PCI resources for this channel are enabled */
        port = port * 2;
        for (i = 0; i < 2; i ++) {
                if (pci_resource_start(pdev, port + i) == 0 ||
                    pci_resource_len(pdev, port + i) == 0)
                        return 0;
        }
        return 1;
}

/**
 *      ata_pci_init_bmdma - acquire PCI BMDMA resources and init ATA host
 *      @host: target ATA host
 *
 *      Acquire PCI BMDMA resources and initialize @host accordingly.
 *
 *      LOCKING:
 *      Inherited from calling layer (may sleep).
 *
 *      RETURNS:
 *      0 on success, -errno otherwise.
 */
int ata_pci_init_bmdma(struct ata_host *host)
{
        struct device *gdev = host->dev;
        struct pci_dev *pdev = to_pci_dev(gdev);
        int i, rc;

        /* No BAR4 allocation: No DMA */
        if (pci_resource_start(pdev, 4) == 0)
                return 0;

        /* TODO: If we get no DMA mask we should fall back to PIO */
        rc = pci_set_dma_mask(pdev, ATA_DMA_MASK);
        if (rc)
                return rc;
        rc = pci_set_consistent_dma_mask(pdev, ATA_DMA_MASK);
        if (rc)
                return rc;

        /* request and iomap DMA region */
        rc = pcim_iomap_regions(pdev, 1 << 4, dev_driver_string(gdev));
        if (rc) {
                dev_printk(KERN_ERR, gdev, "failed to request/iomap BAR4\n");
                return -ENOMEM;
        }
        host->iomap = pcim_iomap_table(pdev);

        for (i = 0; i < 2; i++) {
                struct ata_port *ap = host->ports[i];
                void __iomem *bmdma = host->iomap[4] + 8 * i;

                if (ata_port_is_dummy(ap))
                        continue;

                ap->ioaddr.bmdma_addr = bmdma;
                if ((!(ap->flags & ATA_FLAG_IGN_SIMPLEX)) &&
                    (ioread8(bmdma + 2) & 0x80))
                        host->flags |= ATA_HOST_SIMPLEX;

                ata_port_desc(ap, "bmdma 0x%llx",
                        (unsigned long long)pci_resource_start(pdev, 4) + 8 * i);
        }

        return 0;
}

/**
 *      ata_pci_init_sff_host - acquire native PCI ATA resources and init host
 *      @host: target ATA host
 *
 *      Acquire native PCI ATA resources for @host and initialize the
 *      first two ports of @host accordingly.  Ports marked dummy are
 *      skipped and allocation failure makes the port dummy.
 *
 *      Note that native PCI resources are valid even for legacy hosts
 *      as we fix up pdev resources array early in boot, so this
 *      function can be used for both native and legacy SFF hosts.
 *
 *      LOCKING:
 *      Inherited from calling layer (may sleep).
 *
 *      RETURNS:
 *      0 if at least one port is initialized, -ENODEV if no port is
 *      available.
 */
int ata_pci_init_sff_host(struct ata_host *host)
{
        struct device *gdev = host->dev;
        struct pci_dev *pdev = to_pci_dev(gdev);
        unsigned int mask = 0;
        int i, rc;

        /* request, iomap BARs and init port addresses accordingly */
        for (i = 0; i < 2; i++) {
                struct ata_port *ap = host->ports[i];
                int base = i * 2;
                void __iomem * const *iomap;

                if (ata_port_is_dummy(ap))
                        continue;

                /* Discard disabled ports.  Some controllers show
                 * their unused channels this way.  Disabled ports are
                 * made dummy.
                 */
                if (!ata_resources_present(pdev, i)) {
                        ap->ops = &ata_dummy_port_ops;
                        continue;
                }

                rc = pcim_iomap_regions(pdev, 0x3 << base,
                                        dev_driver_string(gdev));
                if (rc) {
                        dev_printk(KERN_WARNING, gdev,
                                   "failed to request/iomap BARs for port %d "
                                   "(errno=%d)\n", i, rc);
                        if (rc == -EBUSY)
                                pcim_pin_device(pdev);
                        ap->ops = &ata_dummy_port_ops;
                        continue;
                }
                host->iomap = iomap = pcim_iomap_table(pdev);

                ap->ioaddr.cmd_addr = iomap[base];
                ap->ioaddr.altstatus_addr =
                ap->ioaddr.ctl_addr = (void __iomem *)
                        ((unsigned long)iomap[base + 1] | ATA_PCI_CTL_OFS);
                ata_std_ports(&ap->ioaddr);

                ata_port_desc(ap, "cmd 0x%llx ctl 0x%llx",
                        (unsigned long long)pci_resource_start(pdev, base),
                        (unsigned long long)pci_resource_start(pdev, base + 1));

                mask |= 1 << i;
        }

        if (!mask) {
                dev_printk(KERN_ERR, gdev, "no available native port\n");
                return -ENODEV;
        }

        return 0;
}

/**
 *      ata_pci_prepare_sff_host - helper to prepare native PCI ATA host
 *      @pdev: target PCI device
 *      @ppi: array of port_info, must be enough for two ports
 *      @r_host: out argument for the initialized ATA host
 *
 *      Helper to allocate ATA host for @pdev, acquire all native PCI
 *      resources and initialize it accordingly in one go.
 *
 *      LOCKING:
 *      Inherited from calling layer (may sleep).
 *
 *      RETURNS:
 *      0 on success, -errno otherwise.
 */
int ata_pci_prepare_sff_host(struct pci_dev *pdev,
                             const struct ata_port_info * const * ppi,
                             struct ata_host **r_host)
{
        struct ata_host *host;
        int rc;

        if (!devres_open_group(&pdev->dev, NULL, GFP_KERNEL))
                return -ENOMEM;

        host = ata_host_alloc_pinfo(&pdev->dev, ppi, 2);
        if (!host) {
                dev_printk(KERN_ERR, &pdev->dev,
                           "failed to allocate ATA host\n");
                rc = -ENOMEM;
                goto err_out;
        }

        rc = ata_pci_init_sff_host(host);
        if (rc)
                goto err_out;

        /* init DMA related stuff */
        rc = ata_pci_init_bmdma(host);
        if (rc)
                goto err_bmdma;

        devres_remove_group(&pdev->dev, NULL);
        *r_host = host;
        return 0;

 err_bmdma:
        /* This is necessary because PCI and iomap resources are
         * merged and releasing the top group won't release the
         * acquired resources if some of those have been acquired
         * before entering this function.
         */
        pcim_iounmap_regions(pdev, 0xf);
 err_out:
        devres_release_group(&pdev->dev, NULL);
        return rc;
}

/**
 *      ata_pci_activate_sff_host - start SFF host, request IRQ and register it
 *      @host: target SFF ATA host
 *      @irq_handler: irq_handler used when requesting IRQ(s)
 *      @sht: scsi_host_template to use when registering the host
 *
 *      This is the counterpart of ata_host_activate() for SFF ATA
 *      hosts.  This separate helper is necessary because SFF hosts
 *      use two separate interrupts in legacy mode.
 *
 *      LOCKING:
 *      Inherited from calling layer (may sleep).
 *
 *      RETURNS:
 *      0 on success, -errno otherwise.
 */
int ata_pci_activate_sff_host(struct ata_host *host,
                              irq_handler_t irq_handler,
                              struct scsi_host_template *sht)
{
        struct device *dev = host->dev;
        struct pci_dev *pdev = to_pci_dev(dev);
        const char *drv_name = dev_driver_string(host->dev);
        int legacy_mode = 0, rc;

        rc = ata_host_start(host);
        if (rc)
                return rc;

        if ((pdev->class >> 8) == PCI_CLASS_STORAGE_IDE) {
                u8 tmp8, mask;

                /* TODO: What if one channel is in native mode ... */
                pci_read_config_byte(pdev, PCI_CLASS_PROG, &tmp8);
                mask = (1 << 2) | (1 << 0);
                if ((tmp8 & mask) != mask)
                        legacy_mode = 1;
#if defined(CONFIG_NO_ATA_LEGACY)
                /* Some platforms with PCI limits cannot address compat
                   port space. In that case we punt if their firmware has
                   left a device in compatibility mode */
                if (legacy_mode) {
                        printk(KERN_ERR "ata: Compatibility mode ATA is not supported on this platform, skipping.\n");
                        return -EOPNOTSUPP;
                }
#endif
        }

        if (!devres_open_group(dev, NULL, GFP_KERNEL))
                return -ENOMEM;

        if (!legacy_mode && pdev->irq) {
                rc = devm_request_irq(dev, pdev->irq, irq_handler,
                                      IRQF_SHARED, drv_name, host);
                if (rc)
                        goto out;

                ata_port_desc(host->ports[0], "irq %d", pdev->irq);
                ata_port_desc(host->ports[1], "irq %d", pdev->irq);
        } else if (legacy_mode) {
                if (!ata_port_is_dummy(host->ports[0])) {
                        rc = devm_request_irq(dev, ATA_PRIMARY_IRQ(pdev),
                                              irq_handler, IRQF_SHARED,
                                              drv_name, host);
                        if (rc)
                                goto out;

                        ata_port_desc(host->ports[0], "irq %d",
                                      ATA_PRIMARY_IRQ(pdev));
                }

                if (!ata_port_is_dummy(host->ports[1])) {
                        rc = devm_request_irq(dev, ATA_SECONDARY_IRQ(pdev),
                                              irq_handler, IRQF_SHARED,
                                              drv_name, host);
                        if (rc)
                                goto out;

                        ata_port_desc(host->ports[1], "irq %d",
                                      ATA_SECONDARY_IRQ(pdev));
                }
        }

        rc = ata_host_register(host, sht);
 out:
        if (rc == 0)
                devres_remove_group(dev, NULL);
        else
                devres_release_group(dev, NULL);

        return rc;
}

/**
 *      ata_pci_init_one - Initialize/register PCI IDE host controller
 *      @pdev: Controller to be initialized
 *      @ppi: array of port_info, must be enough for two ports
 *
 *      This is a helper function which can be called from a driver's
 *      xxx_init_one() probe function if the hardware uses traditional
 *      IDE taskfile registers.
 *
 *      This function calls pci_enable_device(), reserves its register
 *      regions, sets the dma mask, enables bus master mode, and calls
 *      ata_device_add()
 *
 *      ASSUMPTION:
 *      Nobody makes a single channel controller that appears solely as
 *      the secondary legacy port on PCI.
 *
 *      LOCKING:
 *      Inherited from PCI layer (may sleep).
 *
 *      RETURNS:
 *      Zero on success, negative on errno-based value on error.
 */
int ata_pci_init_one(struct pci_dev *pdev,
                     const struct ata_port_info * const * ppi)
{
        struct device *dev = &pdev->dev;
        const struct ata_port_info *pi = NULL;
        struct ata_host *host = NULL;
        int i, rc;

        DPRINTK("ENTER\n");

        /* look up the first valid port_info */
        for (i = 0; i < 2 && ppi[i]; i++) {
                if (ppi[i]->port_ops != &ata_dummy_port_ops) {
                        pi = ppi[i];
                        break;
                }
        }

        if (!pi) {
                dev_printk(KERN_ERR, &pdev->dev,
                           "no valid port_info specified\n");
                return -EINVAL;
        }

        if (!devres_open_group(dev, NULL, GFP_KERNEL))
                return -ENOMEM;

        rc = pcim_enable_device(pdev);
        if (rc)
                goto out;

        /* prepare and activate SFF host */
        rc = ata_pci_prepare_sff_host(pdev, ppi, &host);
        if (rc)
                goto out;

        pci_set_master(pdev);
        rc = ata_pci_activate_sff_host(host, pi->port_ops->irq_handler,
                                       pi->sht);
 out:
        if (rc == 0)
                devres_remove_group(&pdev->dev, NULL);
        else
                devres_release_group(&pdev->dev, NULL);

        return rc;
}

/**
 *      ata_pci_clear_simplex   -       attempt to kick device out of simplex
 *      @pdev: PCI device
 *
 *      Some PCI ATA devices report simplex mode but in fact can be told to
 *      enter non simplex mode. This implements the necessary logic to
 *      perform the task on such devices. Calling it on other devices will
 *      have -undefined- behaviour.
 */

int ata_pci_clear_simplex(struct pci_dev *pdev)
{
        unsigned long bmdma = pci_resource_start(pdev, 4);
        u8 simplex;

        if (bmdma == 0)
                return -ENOENT;

        simplex = inb(bmdma + 0x02);
        outb(simplex & 0x60, bmdma + 0x02);
        simplex = inb(bmdma + 0x02);
        if (simplex & 0x80)
                return -EOPNOTSUPP;
        return 0;
}

unsigned long ata_pci_default_filter(struct ata_device *adev, unsigned long xfer_mask)
{
        /* Filter out DMA modes if the device has been configured by
           the BIOS as PIO only */

        if (adev->link->ap->ioaddr.bmdma_addr == NULL)
                xfer_mask &= ~(ATA_MASK_MWDMA | ATA_MASK_UDMA);
        return xfer_mask;
}

#endif /* CONFIG_PCI */