[IPV4]: Fix warning in ip_mc_rejoin_group.

[pv_ops_mirror.git] / drivers / ata / libata-acpi.c

/*
 * libata-acpi.c
 * Provides ACPI support for PATA/SATA.
 *
 * Copyright (C) 2006 Intel Corp.
 * Copyright (C) 2006 Randy Dunlap
 */

#include <linux/ata.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/acpi.h>
#include <linux/libata.h>
#include <linux/pci.h>
#include "libata.h"

#include <acpi/acpi_bus.h>
#include <acpi/acnames.h>
#include <acpi/acnamesp.h>
#include <acpi/acparser.h>
#include <acpi/acexcep.h>
#include <acpi/acmacros.h>
#include <acpi/actypes.h>

#define SATA_ROOT_PORT(x)       (((x) >> 16) & 0xffff)
#define SATA_PORT_NUMBER(x)     ((x) & 0xffff)  /* or NO_PORT_MULT */
#define NO_PORT_MULT            0xffff
#define SATA_ADR_RSVD           0xffffffff

#define REGS_PER_GTF            7
struct taskfile_array {
        u8      tfa[REGS_PER_GTF];      /* regs. 0x1f1 - 0x1f7 */
};

/*
 *      Helper - belongs in the PCI layer somewhere eventually
 */
static int is_pci_dev(struct device *dev)
{
        return (dev->bus == &pci_bus_type);
}

/**
 * sata_get_dev_handle - finds acpi_handle and PCI device.function
 * @dev: device to locate
 * @handle: returned acpi_handle for @dev
 * @pcidevfn: return PCI device.func for @dev
 *
 * This function is somewhat SATA-specific.  Or at least the
 * PATA & SATA versions of this function are different,
 * so it's not entirely generic code.
 *
 * Returns 0 on success, <0 on error.
 */
static int sata_get_dev_handle(struct device *dev, acpi_handle *handle,
                                        acpi_integer *pcidevfn)
{
        struct pci_dev  *pci_dev;
        acpi_integer    addr;

        if (!is_pci_dev(dev))
                return -ENODEV;

        pci_dev = to_pci_dev(dev);      /* NOTE: PCI-specific */
        /* Please refer to the ACPI spec for the syntax of _ADR. */
        addr = (PCI_SLOT(pci_dev->devfn) << 16) | PCI_FUNC(pci_dev->devfn);
        *pcidevfn = addr;
        *handle = acpi_get_child(DEVICE_ACPI_HANDLE(dev->parent), addr);
        if (!*handle)
                return -ENODEV;
        return 0;
}

/**
 * pata_get_dev_handle - finds acpi_handle and PCI device.function
 * @dev: device to locate
 * @handle: returned acpi_handle for @dev
 * @pcidevfn: return PCI device.func for @dev
 *
 * The PATA and SATA versions of this function are different.
 *
 * Returns 0 on success, <0 on error.
 */
static int pata_get_dev_handle(struct device *dev, acpi_handle *handle,
                                acpi_integer *pcidevfn)
{
        unsigned int bus, devnum, func;
        acpi_integer addr;
        acpi_handle dev_handle, parent_handle;
        struct acpi_buffer buffer = {.length = ACPI_ALLOCATE_BUFFER,
                                        .pointer = NULL};
        acpi_status status;
        struct acpi_device_info *dinfo = NULL;
        int ret = -ENODEV;
        struct pci_dev *pdev;

        if (!is_pci_dev(dev))
                return -ENODEV;

        pdev = to_pci_dev(dev);

        bus = pdev->bus->number;
        devnum = PCI_SLOT(pdev->devfn);
        func = PCI_FUNC(pdev->devfn);

        dev_handle = DEVICE_ACPI_HANDLE(dev);
        parent_handle = DEVICE_ACPI_HANDLE(dev->parent);

        status = acpi_get_object_info(parent_handle, &buffer);
        if (ACPI_FAILURE(status))
                goto err;

        dinfo = buffer.pointer;
        if (dinfo && (dinfo->valid & ACPI_VALID_ADR) &&
            dinfo->address == bus) {
                /* ACPI spec for _ADR for PCI bus: */
                addr = (acpi_integer)(devnum << 16 | func);
                *pcidevfn = addr;
                *handle = dev_handle;
        } else {
                goto err;
        }

        if (!*handle)
                goto err;
        ret = 0;
err:
        kfree(dinfo);
        return ret;
}

struct walk_info {              /* can be trimmed some */
        struct device   *dev;
        struct acpi_device *adev;
        acpi_handle     handle;
        acpi_integer    pcidevfn;
        unsigned int    drivenum;
        acpi_handle     obj_handle;
        struct ata_port *ataport;
        struct ata_device *atadev;
        u32             sata_adr;
        int             status;
        char            basepath[ACPI_PATHNAME_MAX];
        int             basepath_len;
};

static acpi_status get_devices(acpi_handle handle,
                                u32 level, void *context, void **return_value)
{
        acpi_status             status;
        struct walk_info        *winfo = context;
        struct acpi_buffer      namebuf = {ACPI_ALLOCATE_BUFFER, NULL};
        char                    *pathname;
        struct acpi_buffer      buffer;
        struct acpi_device_info *dinfo;

        status = acpi_get_name(handle, ACPI_FULL_PATHNAME, &namebuf);
        if (status)
                goto ret;
        pathname = namebuf.pointer;

        buffer.length = ACPI_ALLOCATE_BUFFER;
        buffer.pointer = NULL;
        status = acpi_get_object_info(handle, &buffer);
        if (ACPI_FAILURE(status))
                goto out2;

        dinfo = buffer.pointer;

        /* find full device path name for pcidevfn */
        if (dinfo && (dinfo->valid & ACPI_VALID_ADR) &&
            dinfo->address == winfo->pcidevfn) {
                if (ata_msg_probe(winfo->ataport))
                        ata_dev_printk(winfo->atadev, KERN_DEBUG,
                                ":%s: matches pcidevfn (0x%llx)\n",
                                pathname, winfo->pcidevfn);
                strlcpy(winfo->basepath, pathname,
                        sizeof(winfo->basepath));
                winfo->basepath_len = strlen(pathname);
                goto out;
        }

        /* if basepath is not yet known, ignore this object */
        if (!winfo->basepath_len)
                goto out;

        /* if this object is in scope of basepath, maybe use it */
        if (strncmp(pathname, winfo->basepath,
            winfo->basepath_len) == 0) {
                if (!(dinfo->valid & ACPI_VALID_ADR))
                        goto out;
                if (ata_msg_probe(winfo->ataport))
                        ata_dev_printk(winfo->atadev, KERN_DEBUG,
                                "GOT ONE: (%s) root_port = 0x%llx,"
                                " port_num = 0x%llx\n", pathname,
                                SATA_ROOT_PORT(dinfo->address),
                                SATA_PORT_NUMBER(dinfo->address));
                /* heuristics: */
                if (SATA_PORT_NUMBER(dinfo->address) != NO_PORT_MULT)
                        if (ata_msg_probe(winfo->ataport))
                                ata_dev_printk(winfo->atadev,
                                        KERN_DEBUG, "warning: don't"
                                        " know how to handle SATA port"
                                        " multiplier\n");
                if (SATA_ROOT_PORT(dinfo->address) ==
                        winfo->ataport->port_no &&
                    SATA_PORT_NUMBER(dinfo->address) == NO_PORT_MULT) {
                        if (ata_msg_probe(winfo->ataport))
                                ata_dev_printk(winfo->atadev,
                                        KERN_DEBUG,
                                        "THIS ^^^^^ is the requested"
                                        " SATA drive (handle = 0x%p)\n",
                                        handle);
                        winfo->sata_adr = dinfo->address;
                        winfo->obj_handle = handle;
                }
        }
out:
        kfree(dinfo);
out2:
        kfree(pathname);

ret:
        return status;
}

/* Get the SATA drive _ADR object. */
static int get_sata_adr(struct device *dev, acpi_handle handle,
                        acpi_integer pcidevfn, unsigned int drive,
                        struct ata_port *ap,
                        struct ata_device *atadev, u32 *dev_adr)
{
        acpi_status     status;
        struct walk_info *winfo;
        int             err = -ENOMEM;

        winfo = kzalloc(sizeof(struct walk_info), GFP_KERNEL);
        if (!winfo)
                goto out;

        winfo->dev = dev;
        winfo->atadev = atadev;
        winfo->ataport = ap;
        if (acpi_bus_get_device(handle, &winfo->adev) < 0)
                if (ata_msg_probe(ap))
                        ata_dev_printk(winfo->atadev, KERN_DEBUG,
                                "acpi_bus_get_device failed\n");
        winfo->handle = handle;
        winfo->pcidevfn = pcidevfn;
        winfo->drivenum = drive;

        status = acpi_get_devices(NULL, get_devices, winfo, NULL);
        if (ACPI_FAILURE(status)) {
                if (ata_msg_probe(ap))
                        ata_dev_printk(winfo->atadev, KERN_DEBUG,
                                "%s: acpi_get_devices failed\n",
                                __FUNCTION__);
                err = -ENODEV;
        } else {
                *dev_adr = winfo->sata_adr;
                atadev->obj_handle = winfo->obj_handle;
                err = 0;
        }
        kfree(winfo);
out:
        return err;
}

/**
 * do_drive_get_GTF - get the drive bootup default taskfile settings
 * @ap: the ata_port for the drive
 * @ix: target ata_device (drive) index
 * @gtf_length: number of bytes of _GTF data returned at @gtf_address
 * @gtf_address: buffer containing _GTF taskfile arrays
 *
 * This applies to both PATA and SATA drives.
 *
 * The _GTF method has no input parameters.
 * It returns a variable number of register set values (registers
 * hex 1F1..1F7, taskfiles).
 * The <variable number> is not known in advance, so have ACPI-CA
 * allocate the buffer as needed and return it, then free it later.
 *
 * The returned @gtf_length and @gtf_address are only valid if the
 * function return value is 0.
 */
static int do_drive_get_GTF(struct ata_port *ap, int ix,
                        unsigned int *gtf_length, unsigned long *gtf_address,
                        unsigned long *obj_loc)
{
        acpi_status                     status;
        acpi_handle                     dev_handle = NULL;
        acpi_handle                     chan_handle, drive_handle;
        acpi_integer                    pcidevfn = 0;
        u32                             dev_adr;
        struct acpi_buffer              output;
        union acpi_object               *out_obj;
        struct device                   *dev = ap->host->dev;
        struct ata_device               *atadev = &ap->device[ix];
        int                             err = -ENODEV;

        *gtf_length = 0;
        *gtf_address = 0UL;
        *obj_loc = 0UL;

        if (noacpi)
                return 0;

        if (ata_msg_probe(ap))
                ata_dev_printk(atadev, KERN_DEBUG, "%s: ENTER: port#: %d\n",
                               __FUNCTION__, ap->port_no);

        if (!ata_dev_enabled(atadev) || (ap->flags & ATA_FLAG_DISABLED)) {
                if (ata_msg_probe(ap))
                        ata_dev_printk(atadev, KERN_DEBUG, "%s: ERR: "
                                "ata_dev_present: %d, PORT_DISABLED: %lu\n",
                                __FUNCTION__, ata_dev_enabled(atadev),
                                ap->flags & ATA_FLAG_DISABLED);
                goto out;
        }

        /* Don't continue if device has no _ADR method.
         * _GTF is intended for known motherboard devices. */
        if (!(ap->cbl == ATA_CBL_SATA)) {
                err = pata_get_dev_handle(dev, &dev_handle, &pcidevfn);
                if (err < 0) {
                        if (ata_msg_probe(ap))
                                ata_dev_printk(atadev, KERN_DEBUG,
                                        "%s: pata_get_dev_handle failed (%d)\n",
                                        __FUNCTION__, err);
                        goto out;
                }
        } else {
                err = sata_get_dev_handle(dev, &dev_handle, &pcidevfn);
                if (err < 0) {
                        if (ata_msg_probe(ap))
                                ata_dev_printk(atadev, KERN_DEBUG,
                                        "%s: sata_get_dev_handle failed (%d\n",
                                        __FUNCTION__, err);
                        goto out;
                }
        }

        /* Get this drive's _ADR info. if not already known. */
        if (!atadev->obj_handle) {
                if (!(ap->cbl == ATA_CBL_SATA)) {
                        /* get child objects of dev_handle == channel objects,
                         * + _their_ children == drive objects */
                        /* channel is ap->port_no */
                        chan_handle = acpi_get_child(dev_handle,
                                                ap->port_no);
                        if (ata_msg_probe(ap))
                                ata_dev_printk(atadev, KERN_DEBUG,
                                        "%s: chan adr=%d: chan_handle=0x%p\n",
                                        __FUNCTION__, ap->port_no,
                                        chan_handle);
                        if (!chan_handle) {
                                err = -ENODEV;
                                goto out;
                        }
                        /* TBD: could also check ACPI object VALID bits */
                        drive_handle = acpi_get_child(chan_handle, ix);
                        if (!drive_handle) {
                                err = -ENODEV;
                                goto out;
                        }
                        dev_adr = ix;
                        atadev->obj_handle = drive_handle;
                } else {        /* for SATA mode */
                        dev_adr = SATA_ADR_RSVD;
                        err = get_sata_adr(dev, dev_handle, pcidevfn, 0,
                                        ap, atadev, &dev_adr);
                }
                if (err < 0 || dev_adr == SATA_ADR_RSVD ||
                    !atadev->obj_handle) {
                        if (ata_msg_probe(ap))
                                ata_dev_printk(atadev, KERN_DEBUG,
                                        "%s: get_sata/pata_adr failed: "
                                        "err=%d, dev_adr=%u, obj_handle=0x%p\n",
                                        __FUNCTION__, err, dev_adr,
                                        atadev->obj_handle);
                        goto out;
                }
        }

        /* Setting up output buffer */
        output.length = ACPI_ALLOCATE_BUFFER;
        output.pointer = NULL;  /* ACPI-CA sets this; save/free it later */

        /* _GTF has no input parameters */
        err = -EIO;
        status = acpi_evaluate_object(atadev->obj_handle, "_GTF",
                                        NULL, &output);
        if (ACPI_FAILURE(status)) {
                if (ata_msg_probe(ap))
                        ata_dev_printk(atadev, KERN_DEBUG,
                                "%s: Run _GTF error: status = 0x%x\n",
                                __FUNCTION__, status);
                goto out;
        }

        if (!output.length || !output.pointer) {
                if (ata_msg_probe(ap))
                        ata_dev_printk(atadev, KERN_DEBUG, "%s: Run _GTF: "
                                "length or ptr is NULL (0x%llx, 0x%p)\n",
                                __FUNCTION__,
                                (unsigned long long)output.length,
                                output.pointer);
                kfree(output.pointer);
                goto out;
        }

        out_obj = output.pointer;
        if (out_obj->type != ACPI_TYPE_BUFFER) {
                kfree(output.pointer);
                if (ata_msg_probe(ap))
                        ata_dev_printk(atadev, KERN_DEBUG, "%s: Run _GTF: "
                                "error: expected object type of "
                                " ACPI_TYPE_BUFFER, got 0x%x\n",
                                __FUNCTION__, out_obj->type);
                err = -ENOENT;
                goto out;
        }

        if (!out_obj->buffer.length || !out_obj->buffer.pointer ||
            out_obj->buffer.length % REGS_PER_GTF) {
                if (ata_msg_drv(ap))
                        ata_dev_printk(atadev, KERN_ERR,
                                "%s: unexpected GTF length (%d) or addr (0x%p)\n",
                                __FUNCTION__, out_obj->buffer.length,
                                out_obj->buffer.pointer);
                err = -ENOENT;
                goto out;
        }

        *gtf_length = out_obj->buffer.length;
        *gtf_address = (unsigned long)out_obj->buffer.pointer;
        *obj_loc = (unsigned long)out_obj;
        if (ata_msg_probe(ap))
                ata_dev_printk(atadev, KERN_DEBUG, "%s: returning "
                        "gtf_length=%d, gtf_address=0x%lx, obj_loc=0x%lx\n",
                        __FUNCTION__, *gtf_length, *gtf_address, *obj_loc);
        err = 0;
out:
        return err;
}

/**
 * taskfile_load_raw - send taskfile registers to host controller
 * @ap: Port to which output is sent
 * @gtf: raw ATA taskfile register set (0x1f1 - 0x1f7)
 *
 * Outputs ATA taskfile to standard ATA host controller using MMIO
 * or PIO as indicated by the ATA_FLAG_MMIO flag.
 * Writes the control, feature, nsect, lbal, lbam, and lbah registers.
 * Optionally (ATA_TFLAG_LBA48) writes hob_feature, hob_nsect,
 * hob_lbal, hob_lbam, and hob_lbah.
 *
 * This function waits for idle (!BUSY and !DRQ) after writing
 * registers.  If the control register has a new value, this
 * function also waits for idle after writing control and before
 * writing the remaining registers.
 *
 * LOCKING: TBD:
 * Inherited from caller.
 */
static void taskfile_load_raw(struct ata_port *ap,
                                struct ata_device *atadev,
                                const struct taskfile_array *gtf)
{
        struct ata_taskfile tf;
        unsigned int err;

        if (ata_msg_probe(ap))
                ata_dev_printk(atadev, KERN_DEBUG, "%s: (0x1f1-1f7): hex: "
                        "%02x %02x %02x %02x %02x %02x %02x\n",
                        __FUNCTION__,
                        gtf->tfa[0], gtf->tfa[1], gtf->tfa[2],
                        gtf->tfa[3], gtf->tfa[4], gtf->tfa[5], gtf->tfa[6]);

        if ((gtf->tfa[0] == 0) && (gtf->tfa[1] == 0) && (gtf->tfa[2] == 0)
            && (gtf->tfa[3] == 0) && (gtf->tfa[4] == 0) && (gtf->tfa[5] == 0)
            && (gtf->tfa[6] == 0))
                return;

        ata_tf_init(atadev, &tf);

        /* convert gtf to tf */
        tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE; /* TBD */
        tf.protocol = atadev->class == ATA_DEV_ATAPI ?
                ATA_PROT_ATAPI_NODATA : ATA_PROT_NODATA;
        tf.feature = gtf->tfa[0];       /* 0x1f1 */
        tf.nsect   = gtf->tfa[1];       /* 0x1f2 */
        tf.lbal    = gtf->tfa[2];       /* 0x1f3 */
        tf.lbam    = gtf->tfa[3];       /* 0x1f4 */
        tf.lbah    = gtf->tfa[4];       /* 0x1f5 */
        tf.device  = gtf->tfa[5];       /* 0x1f6 */
        tf.command = gtf->tfa[6];       /* 0x1f7 */

        err = ata_exec_internal(atadev, &tf, NULL, DMA_NONE, NULL, 0);
        if (err && ata_msg_probe(ap))
                ata_dev_printk(atadev, KERN_ERR,
                        "%s: ata_exec_internal failed: %u\n",
                        __FUNCTION__, err);
}

/**
 * do_drive_set_taskfiles - write the drive taskfile settings from _GTF
 * @ap: the ata_port for the drive
 * @atadev: target ata_device
 * @gtf_length: total number of bytes of _GTF taskfiles
 * @gtf_address: location of _GTF taskfile arrays
 *
 * This applies to both PATA and SATA drives.
 *
 * Write {gtf_address, length gtf_length} in groups of
 * REGS_PER_GTF bytes.
 */
static int do_drive_set_taskfiles(struct ata_port *ap,
                struct ata_device *atadev, unsigned int gtf_length,
                unsigned long gtf_address)
{
        int                     err = -ENODEV;
        int                     gtf_count = gtf_length / REGS_PER_GTF;
        int                     ix;
        struct taskfile_array   *gtf;

        if (ata_msg_probe(ap))
                ata_dev_printk(atadev, KERN_DEBUG, "%s: ENTER: port#: %d\n",
                               __FUNCTION__, ap->port_no);

        if (noacpi || !(ap->cbl == ATA_CBL_SATA))
                return 0;

        if (!ata_dev_enabled(atadev) || (ap->flags & ATA_FLAG_DISABLED))
                goto out;
        if (!gtf_count)         /* shouldn't be here */
                goto out;

        if (gtf_length % REGS_PER_GTF) {
                if (ata_msg_drv(ap))
                        ata_dev_printk(atadev, KERN_ERR,
                                "%s: unexpected GTF length (%d)\n",
                                __FUNCTION__, gtf_length);
                goto out;
        }

        for (ix = 0; ix < gtf_count; ix++) {
                gtf = (struct taskfile_array *)
                        (gtf_address + ix * REGS_PER_GTF);

                /* send all TaskFile registers (0x1f1-0x1f7) *in*that*order* */
                taskfile_load_raw(ap, atadev, gtf);
        }

        err = 0;
out:
        return err;
}

/**
 * ata_acpi_exec_tfs - get then write drive taskfile settings
 * @ap: the ata_port for the drive
 *
 * This applies to both PATA and SATA drives.
 */
int ata_acpi_exec_tfs(struct ata_port *ap)
{
        int             ix;
        int             ret =0;
        unsigned int    gtf_length;
        unsigned long   gtf_address;
        unsigned long   obj_loc;

        if (noacpi)
                return 0;
        /*
         * TBD - implement PATA support.  For now,
         * we should not run GTF on PATA devices since some
         * PATA require execution of GTM/STM before GTF.
         */
        if (!(ap->cbl == ATA_CBL_SATA))
                return 0;

        for (ix = 0; ix < ATA_MAX_DEVICES; ix++) {
                if (!ata_dev_enabled(&ap->device[ix]))
                        continue;

                ret = do_drive_get_GTF(ap, ix,
                                &gtf_length, &gtf_address, &obj_loc);
                if (ret < 0) {
                        if (ata_msg_probe(ap))
                                ata_port_printk(ap, KERN_DEBUG,
                                        "%s: get_GTF error (%d)\n",
                                        __FUNCTION__, ret);
                        break;
                }

                ret = do_drive_set_taskfiles(ap, &ap->device[ix],
                                gtf_length, gtf_address);
                kfree((void *)obj_loc);
                if (ret < 0) {
                        if (ata_msg_probe(ap))
                                ata_port_printk(ap, KERN_DEBUG,
                                        "%s: set_taskfiles error (%d)\n",
                                        __FUNCTION__, ret);
                        break;
                }
        }

        return ret;
}

/**
 * ata_acpi_push_id - send Identify data to drive
 * @ap: the ata_port for the drive
 * @ix: drive index
 *
 * _SDD ACPI object: for SATA mode only
 * Must be after Identify (Packet) Device -- uses its data
 * ATM this function never returns a failure.  It is an optional
 * method and if it fails for whatever reason, we should still
 * just keep going.
 */
int ata_acpi_push_id(struct ata_port *ap, unsigned int ix)
{
        acpi_handle                     handle;
        acpi_integer                    pcidevfn;
        int                             err;
        struct device                   *dev = ap->host->dev;
        struct ata_device               *atadev = &ap->device[ix];
        u32                             dev_adr;
        acpi_status                     status;
        struct acpi_object_list         input;
        union acpi_object               in_params[1];

        if (noacpi)
                return 0;

        if (ata_msg_probe(ap))
                ata_dev_printk(atadev, KERN_DEBUG, "%s: ix = %d, port#: %d\n",
                               __FUNCTION__, ix, ap->port_no);

        /* Don't continue if not a SATA device. */
        if (!(ap->cbl == ATA_CBL_SATA)) {
                if (ata_msg_probe(ap))
                        ata_dev_printk(atadev, KERN_DEBUG,
                                "%s: Not a SATA device\n", __FUNCTION__);
                goto out;
        }

        /* Don't continue if device has no _ADR method.
         * _SDD is intended for known motherboard devices. */
        err = sata_get_dev_handle(dev, &handle, &pcidevfn);
        if (err < 0) {
                if (ata_msg_probe(ap))
                        ata_dev_printk(atadev, KERN_DEBUG,
                                "%s: sata_get_dev_handle failed (%d\n",
                                __FUNCTION__, err);
                goto out;
        }

        /* Get this drive's _ADR info, if not already known */
        if (!atadev->obj_handle) {
                dev_adr = SATA_ADR_RSVD;
                err = get_sata_adr(dev, handle, pcidevfn, ix, ap, atadev,
                                        &dev_adr);
                if (err < 0 || dev_adr == SATA_ADR_RSVD ||
                        !atadev->obj_handle) {
                        if (ata_msg_probe(ap))
                                ata_dev_printk(atadev, KERN_DEBUG,
                                        "%s: get_sata_adr failed: "
                                        "err=%d, dev_adr=%u, obj_handle=0x%p\n",
                                        __FUNCTION__, err, dev_adr,
                                        atadev->obj_handle);
                        goto out;
                }
        }

        /* Give the drive Identify data to the drive via the _SDD method */
        /* _SDD: set up input parameters */
        input.count = 1;
        input.pointer = in_params;
        in_params[0].type = ACPI_TYPE_BUFFER;
        in_params[0].buffer.length = sizeof(atadev->id[0]) * ATA_ID_WORDS;
        in_params[0].buffer.pointer = (u8 *)atadev->id;
        /* Output buffer: _SDD has no output */

        /* It's OK for _SDD to be missing too. */
        swap_buf_le16(atadev->id, ATA_ID_WORDS);
        status = acpi_evaluate_object(atadev->obj_handle, "_SDD", &input, NULL);
        swap_buf_le16(atadev->id, ATA_ID_WORDS);

        err = ACPI_FAILURE(status) ? -EIO : 0;
        if (err < 0) {
                if (ata_msg_probe(ap))
                        ata_dev_printk(atadev, KERN_DEBUG,
                                       "%s _SDD error: status = 0x%x\n",
                                       __FUNCTION__, status);
        }

        /* always return success */
out:
        return 0;
}