sched: run sched_domain_debug() if CONFIG_SCHED_DEBUG=y

[linux-2.6/mini2440.git] / drivers / ide / ide-acpi.c

/*
 * ide-acpi.c
 * Provides ACPI support for IDE drives.
 *
 * Copyright (C) 2005 Intel Corp.
 * Copyright (C) 2005 Randy Dunlap
 * Copyright (C) 2006 SUSE Linux Products GmbH
 * Copyright (C) 2006 Hannes Reinecke
 */

#include <linux/ata.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <acpi/acpi.h>
#include <linux/ide.h>
#include <linux/pci.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 REGS_PER_GTF            7
struct taskfile_array {
        u8      tfa[REGS_PER_GTF];      /* regs. 0x1f1 - 0x1f7 */
};

struct GTM_buffer {
        u32     PIO_speed0;
        u32     DMA_speed0;
        u32     PIO_speed1;
        u32     DMA_speed1;
        u32     GTM_flags;
};

struct ide_acpi_drive_link {
        ide_drive_t     *drive;
        acpi_handle      obj_handle;
        u8               idbuff[512];
};

struct ide_acpi_hwif_link {
        ide_hwif_t                      *hwif;
        acpi_handle                      obj_handle;
        struct GTM_buffer                gtm;
        struct ide_acpi_drive_link       master;
        struct ide_acpi_drive_link       slave;
};

#undef DEBUGGING
/* note: adds function name and KERN_DEBUG */
#ifdef DEBUGGING
#define DEBPRINT(fmt, args...)  \
                printk(KERN_DEBUG "%s: " fmt, __FUNCTION__, ## args)
#else
#define DEBPRINT(fmt, args...)  do {} while (0)
#endif  /* DEBUGGING */

extern int ide_noacpi;
extern int ide_noacpitfs;
extern int ide_noacpionboot;

/**
 * ide_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
 *
 * Returns the ACPI object handle to the corresponding PCI device.
 *
 * Returns 0 on success, <0 on error.
 */
static int ide_get_dev_handle(struct device *dev, acpi_handle *handle,
                               acpi_integer *pcidevfn)
{
        struct pci_dev *pdev = to_pci_dev(dev);
        unsigned int bus, devnum, func;
        acpi_integer addr;
        acpi_handle dev_handle;
        struct acpi_buffer buffer = {.length = ACPI_ALLOCATE_BUFFER,
                                        .pointer = NULL};
        acpi_status status;
        struct acpi_device_info *dinfo = NULL;
        int ret = -ENODEV;

        bus = pdev->bus->number;
        devnum = PCI_SLOT(pdev->devfn);
        func = PCI_FUNC(pdev->devfn);
        /* ACPI _ADR encoding for PCI bus: */
        addr = (acpi_integer)(devnum << 16 | func);

        DEBPRINT("ENTER: pci %02x:%02x.%01x\n", bus, devnum, func);

        dev_handle = DEVICE_ACPI_HANDLE(dev);
        if (!dev_handle) {
                DEBPRINT("no acpi handle for device\n");
                goto err;
        }

        status = acpi_get_object_info(dev_handle, &buffer);
        if (ACPI_FAILURE(status)) {
                DEBPRINT("get_object_info for device failed\n");
                goto err;
        }
        dinfo = buffer.pointer;
        if (dinfo && (dinfo->valid & ACPI_VALID_ADR) &&
            dinfo->address == addr) {
                *pcidevfn = addr;
                *handle = dev_handle;
        } else {
                DEBPRINT("get_object_info for device has wrong "
                        " address: %llu, should be %u\n",
                        dinfo ? (unsigned long long)dinfo->address : -1ULL,
                        (unsigned int)addr);
                goto err;
        }

        DEBPRINT("for dev=0x%x.%x, addr=0x%llx, *handle=0x%p\n",
                 devnum, func, (unsigned long long)addr, *handle);
        ret = 0;
err:
        kfree(dinfo);
        return ret;
}

/**
 * ide_acpi_hwif_get_handle - Get ACPI object handle for a given hwif
 * @hwif: device to locate
 *
 * Retrieves the object handle for a given hwif.
 *
 * Returns handle on success, 0 on error.
 */
static acpi_handle ide_acpi_hwif_get_handle(ide_hwif_t *hwif)
{
        struct device           *dev = hwif->gendev.parent;
        acpi_handle             dev_handle;
        acpi_integer            pcidevfn;
        acpi_handle             chan_handle;
        int                     err;

        DEBPRINT("ENTER: device %s\n", hwif->name);

        if (!dev) {
                DEBPRINT("no PCI device for %s\n", hwif->name);
                return NULL;
        }

        err = ide_get_dev_handle(dev, &dev_handle, &pcidevfn);
        if (err < 0) {
                DEBPRINT("ide_get_dev_handle failed (%d)\n", err);
                return NULL;
        }

        /* get child objects of dev_handle == channel objects,
         * + _their_ children == drive objects */
        /* channel is hwif->channel */
        chan_handle = acpi_get_child(dev_handle, hwif->channel);
        DEBPRINT("chan adr=%d: handle=0x%p\n",
                 hwif->channel, chan_handle);

        return chan_handle;
}

/**
 * ide_acpi_drive_get_handle - Get ACPI object handle for a given drive
 * @drive: device to locate
 *
 * Retrieves the object handle of a given drive. According to the ACPI
 * spec the drive is a child of the hwif.
 *
 * Returns handle on success, 0 on error.
 */
static acpi_handle ide_acpi_drive_get_handle(ide_drive_t *drive)
{
        ide_hwif_t      *hwif = HWIF(drive);
        int              port;
        acpi_handle      drive_handle;

        if (!hwif->acpidata)
                return NULL;

        if (!hwif->acpidata->obj_handle)
                return NULL;

        port = hwif->channel ? drive->dn - 2: drive->dn;

        DEBPRINT("ENTER: %s at channel#: %d port#: %d\n",
                 drive->name, hwif->channel, port);


        /* TBD: could also check ACPI object VALID bits */
        drive_handle = acpi_get_child(hwif->acpidata->obj_handle, port);
        DEBPRINT("drive %s handle 0x%p\n", drive->name, drive_handle);

        return drive_handle;
}

/**
 * do_drive_get_GTF - get the drive bootup default taskfile settings
 * @drive: the drive for which the taskfile settings should be retrieved
 * @gtf_length: number of bytes of _GTF data returned at @gtf_address
 * @gtf_address: buffer containing _GTF taskfile arrays
 *
 * 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(ide_drive_t *drive,
                     unsigned int *gtf_length, unsigned long *gtf_address,
                     unsigned long *obj_loc)
{
        acpi_status                     status;
        struct acpi_buffer              output;
        union acpi_object               *out_obj;
        ide_hwif_t                      *hwif = HWIF(drive);
        struct device                   *dev = hwif->gendev.parent;
        int                             err = -ENODEV;
        int                             port;

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

        if (ide_noacpi)
                return 0;

        if (!dev) {
                DEBPRINT("no PCI device for %s\n", hwif->name);
                goto out;
        }

        if (!hwif->acpidata) {
                DEBPRINT("no ACPI data for %s\n", hwif->name);
                goto out;
        }

        port = hwif->channel ? drive->dn - 2: drive->dn;

        if (!drive->acpidata) {
                if (port == 0) {
                        drive->acpidata = &hwif->acpidata->master;
                        hwif->acpidata->master.drive = drive;
                } else {
                        drive->acpidata = &hwif->acpidata->slave;
                        hwif->acpidata->slave.drive = drive;
                }
        }

        DEBPRINT("ENTER: %s at %s, port#: %d, hard_port#: %d\n",
                 hwif->name, dev->bus_id, port, hwif->channel);

        if (!drive->present) {
                DEBPRINT("%s drive %d:%d not present\n",
                         hwif->name, hwif->channel, port);
                goto out;
        }

        /* Get this drive's _ADR info. if not already known. */
        if (!drive->acpidata->obj_handle) {
                drive->acpidata->obj_handle = ide_acpi_drive_get_handle(drive);
                if (!drive->acpidata->obj_handle) {
                        DEBPRINT("No ACPI object found for %s\n",
                                 drive->name);
                        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(drive->acpidata->obj_handle, "_GTF",
                                      NULL, &output);
        if (ACPI_FAILURE(status)) {
                printk(KERN_DEBUG
                       "%s: Run _GTF error: status = 0x%x\n",
                       __FUNCTION__, status);
                goto out;
        }

        if (!output.length || !output.pointer) {
                DEBPRINT("Run _GTF: "
                       "length or ptr is NULL (0x%llx, 0x%p)\n",
                       (unsigned long long)output.length,
                       output.pointer);
                goto out;
        }

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

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

        *gtf_length = out_obj->buffer.length;
        *gtf_address = (unsigned long)out_obj->buffer.pointer;
        *obj_loc = (unsigned long)out_obj;
        DEBPRINT("returning gtf_length=%d, gtf_address=0x%lx, obj_loc=0x%lx\n",
                 *gtf_length, *gtf_address, *obj_loc);
        err = 0;
out:
        return err;
}

/**
 * taskfile_load_raw - send taskfile registers to drive
 * @drive: drive to which output is sent
 * @gtf: raw ATA taskfile register set (0x1f1 - 0x1f7)
 *
 * Outputs IDE taskfile to the drive.
 */
static int taskfile_load_raw(ide_drive_t *drive,
                              const struct taskfile_array *gtf)
{
        ide_task_t args;
        int err = 0;

        DEBPRINT("(0x1f1-1f7): hex: "
               "%02x %02x %02x %02x %02x %02x %02x\n",
               gtf->tfa[0], gtf->tfa[1], gtf->tfa[2],
               gtf->tfa[3], gtf->tfa[4], gtf->tfa[5], gtf->tfa[6]);

        memset(&args, 0, sizeof(ide_task_t));
        args.command_type = IDE_DRIVE_TASK_NO_DATA;
        args.data_phase   = TASKFILE_IN;
        args.handler      = &task_no_data_intr;

        /* convert gtf to IDE Taskfile */
        args.tfRegister[1] = gtf->tfa[0];       /* 0x1f1 */
        args.tfRegister[2] = gtf->tfa[1];       /* 0x1f2 */
        args.tfRegister[3] = gtf->tfa[2];       /* 0x1f3 */
        args.tfRegister[4] = gtf->tfa[3];       /* 0x1f4 */
        args.tfRegister[5] = gtf->tfa[4];       /* 0x1f5 */
        args.tfRegister[6] = gtf->tfa[5];       /* 0x1f6 */
        args.tfRegister[7] = gtf->tfa[6];       /* 0x1f7 */

        if (ide_noacpitfs) {
                DEBPRINT("_GTF execution disabled\n");
                return err;
        }

        err = ide_raw_taskfile(drive, &args, NULL);
        if (err)
                printk(KERN_ERR "%s: ide_raw_taskfile failed: %u\n",
                       __FUNCTION__, err);

        return err;
}

/**
 * do_drive_set_taskfiles - write the drive taskfile settings from _GTF
 * @drive: the drive to which the taskfile command should be sent
 * @gtf_length: total number of bytes of _GTF taskfiles
 * @gtf_address: location of _GTF taskfile arrays
 *
 * Write {gtf_address, length gtf_length} in groups of
 * REGS_PER_GTF bytes.
 */
static int do_drive_set_taskfiles(ide_drive_t *drive,
                                  unsigned int gtf_length,
                                  unsigned long gtf_address)
{
        int                     rc = -ENODEV, err;
        int                     gtf_count = gtf_length / REGS_PER_GTF;
        int                     ix;
        struct taskfile_array   *gtf;

        if (ide_noacpi)
                return 0;

        DEBPRINT("ENTER: %s, hard_port#: %d\n", drive->name, drive->dn);

        if (!drive->present)
                goto out;
        if (!gtf_count)         /* shouldn't be here */
                goto out;

        DEBPRINT("total GTF bytes=%u (0x%x), gtf_count=%d, addr=0x%lx\n",
                 gtf_length, gtf_length, gtf_count, gtf_address);

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

        rc = 0;
        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* */
                err = taskfile_load_raw(drive, gtf);
                if (err)
                        rc = err;
        }

out:
        return rc;
}

/**
 * ide_acpi_exec_tfs - get then write drive taskfile settings
 * @drive: the drive for which the taskfile settings should be
 *         written.
 *
 * According to the ACPI spec this should be called after _STM
 * has been evaluated for the interface. Some ACPI vendors interpret
 * that as a hard requirement and modify the taskfile according
 * to the Identify Drive information passed down with _STM.
 * So one should really make sure to call this only after _STM has
 * been executed.
 */
int ide_acpi_exec_tfs(ide_drive_t *drive)
{
        int             ret;
        unsigned int    gtf_length;
        unsigned long   gtf_address;
        unsigned long   obj_loc;

        if (ide_noacpi)
                return 0;

        DEBPRINT("call get_GTF, drive=%s port=%d\n", drive->name, drive->dn);

        ret = do_drive_get_GTF(drive, &gtf_length, &gtf_address, &obj_loc);
        if (ret < 0) {
                DEBPRINT("get_GTF error (%d)\n", ret);
                return ret;
        }

        DEBPRINT("call set_taskfiles, drive=%s\n", drive->name);

        ret = do_drive_set_taskfiles(drive, gtf_length, gtf_address);
        kfree((void *)obj_loc);
        if (ret < 0) {
                DEBPRINT("set_taskfiles error (%d)\n", ret);
        }

        DEBPRINT("ret=%d\n", ret);

        return ret;
}
EXPORT_SYMBOL_GPL(ide_acpi_exec_tfs);

/**
 * ide_acpi_get_timing - get the channel (controller) timings
 * @hwif: target IDE interface (channel)
 *
 * This function executes the _GTM ACPI method for the target channel.
 *
 */
void ide_acpi_get_timing(ide_hwif_t *hwif)
{
        acpi_status             status;
        struct acpi_buffer      output;
        union acpi_object       *out_obj;

        if (ide_noacpi)
                return;

        DEBPRINT("ENTER:\n");

        if (!hwif->acpidata) {
                DEBPRINT("no ACPI data for %s\n", hwif->name);
                return;
        }

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

        /* _GTM has no input parameters */
        status = acpi_evaluate_object(hwif->acpidata->obj_handle, "_GTM",
                                      NULL, &output);

        DEBPRINT("_GTM status: %d, outptr: 0x%p, outlen: 0x%llx\n",
                 status, output.pointer,
                 (unsigned long long)output.length);

        if (ACPI_FAILURE(status)) {
                DEBPRINT("Run _GTM error: status = 0x%x\n", status);
                return;
        }

        if (!output.length || !output.pointer) {
                DEBPRINT("Run _GTM: length or ptr is NULL (0x%llx, 0x%p)\n",
                       (unsigned long long)output.length,
                       output.pointer);
                kfree(output.pointer);
                return;
        }

        out_obj = output.pointer;
        if (out_obj->type != ACPI_TYPE_BUFFER) {
                kfree(output.pointer);
                DEBPRINT("Run _GTM: error: "
                       "expected object type of ACPI_TYPE_BUFFER, "
                       "got 0x%x\n", out_obj->type);
                return;
        }

        if (!out_obj->buffer.length || !out_obj->buffer.pointer ||
            out_obj->buffer.length != sizeof(struct GTM_buffer)) {
                kfree(output.pointer);
                printk(KERN_ERR
                        "%s: unexpected _GTM length (0x%x)[should be 0x%zx] or "
                        "addr (0x%p)\n",
                        __FUNCTION__, out_obj->buffer.length,
                        sizeof(struct GTM_buffer), out_obj->buffer.pointer);
                return;
        }

        memcpy(&hwif->acpidata->gtm, out_obj->buffer.pointer,
               sizeof(struct GTM_buffer));

        DEBPRINT("_GTM info: ptr: 0x%p, len: 0x%x, exp.len: 0x%Zx\n",
                 out_obj->buffer.pointer, out_obj->buffer.length,
                 sizeof(struct GTM_buffer));

        DEBPRINT("_GTM fields: 0x%x, 0x%x, 0x%x, 0x%x, 0x%x\n",
                 hwif->acpidata->gtm.PIO_speed0,
                 hwif->acpidata->gtm.DMA_speed0,
                 hwif->acpidata->gtm.PIO_speed1,
                 hwif->acpidata->gtm.DMA_speed1,
                 hwif->acpidata->gtm.GTM_flags);

        kfree(output.pointer);
}
EXPORT_SYMBOL_GPL(ide_acpi_get_timing);

/**
 * ide_acpi_push_timing - set the channel (controller) timings
 * @hwif: target IDE interface (channel)
 *
 * This function executes the _STM ACPI method for the target channel.
 *
 * _STM requires Identify Drive data, which has to passed as an argument.
 * Unfortunately hd_driveid is a mangled version which we can't readily
 * use; hence we'll get the information afresh.
 */
void ide_acpi_push_timing(ide_hwif_t *hwif)
{
        acpi_status             status;
        struct acpi_object_list input;
        union acpi_object       in_params[3];
        struct ide_acpi_drive_link      *master = &hwif->acpidata->master;
        struct ide_acpi_drive_link      *slave = &hwif->acpidata->slave;

        if (ide_noacpi)
                return;

        DEBPRINT("ENTER:\n");

        if (!hwif->acpidata) {
                DEBPRINT("no ACPI data for %s\n", hwif->name);
                return;
        }

        /* Give the GTM buffer + drive Identify data to the channel via the
         * _STM method: */
        /* setup input parameters buffer for _STM */
        input.count = 3;
        input.pointer = in_params;
        in_params[0].type = ACPI_TYPE_BUFFER;
        in_params[0].buffer.length = sizeof(struct GTM_buffer);
        in_params[0].buffer.pointer = (u8 *)&hwif->acpidata->gtm;
        in_params[1].type = ACPI_TYPE_BUFFER;
        in_params[1].buffer.length = sizeof(struct hd_driveid);
        in_params[1].buffer.pointer = (u8 *)&master->idbuff;
        in_params[2].type = ACPI_TYPE_BUFFER;
        in_params[2].buffer.length = sizeof(struct hd_driveid);
        in_params[2].buffer.pointer = (u8 *)&slave->idbuff;
        /* Output buffer: _STM has no output */

        status = acpi_evaluate_object(hwif->acpidata->obj_handle, "_STM",
                                      &input, NULL);

        if (ACPI_FAILURE(status)) {
                DEBPRINT("Run _STM error: status = 0x%x\n", status);
        }
        DEBPRINT("_STM status: %d\n", status);
}
EXPORT_SYMBOL_GPL(ide_acpi_push_timing);

/**
 * ide_acpi_set_state - set the channel power state
 * @hwif: target IDE interface
 * @on: state, on/off
 *
 * This function executes the _PS0/_PS3 ACPI method to set the power state.
 * ACPI spec requires _PS0 when IDE power on and _PS3 when power off
 */
void ide_acpi_set_state(ide_hwif_t *hwif, int on)
{
        int unit;

        if (ide_noacpi)
                return;

        DEBPRINT("ENTER:\n");

        if (!hwif->acpidata) {
                DEBPRINT("no ACPI data for %s\n", hwif->name);
                return;
        }
        /* channel first and then drives for power on and verse versa for power off */
        if (on)
                acpi_bus_set_power(hwif->acpidata->obj_handle, ACPI_STATE_D0);
        for (unit = 0; unit < MAX_DRIVES; ++unit) {
                ide_drive_t *drive = &hwif->drives[unit];

                if (!drive->acpidata->obj_handle)
                        drive->acpidata->obj_handle = ide_acpi_drive_get_handle(drive);

                if (drive->acpidata->obj_handle && drive->present) {
                        acpi_bus_set_power(drive->acpidata->obj_handle,
                                on? ACPI_STATE_D0: ACPI_STATE_D3);
                }
        }
        if (!on)
                acpi_bus_set_power(hwif->acpidata->obj_handle, ACPI_STATE_D3);
}

/**
 * ide_acpi_init - initialize the ACPI link for an IDE interface
 * @hwif: target IDE interface (channel)
 *
 * The ACPI spec is not quite clear when the drive identify buffer
 * should be obtained. Calling IDENTIFY DEVICE during shutdown
 * is not the best of ideas as the drive might already being put to
 * sleep. And obviously we can't call it during resume.
 * So we get the information during startup; but this means that
 * any changes during run-time will be lost after resume.
 */
void ide_acpi_init(ide_hwif_t *hwif)
{
        int unit;
        int                     err;
        struct ide_acpi_drive_link      *master;
        struct ide_acpi_drive_link      *slave;

        hwif->acpidata = kzalloc(sizeof(struct ide_acpi_hwif_link), GFP_KERNEL);
        if (!hwif->acpidata)
                return;

        hwif->acpidata->obj_handle = ide_acpi_hwif_get_handle(hwif);
        if (!hwif->acpidata->obj_handle) {
                DEBPRINT("no ACPI object for %s found\n", hwif->name);
                kfree(hwif->acpidata);
                hwif->acpidata = NULL;
                return;
        }

        /*
         * The ACPI spec mandates that we send information
         * for both drives, regardless whether they are connected
         * or not.
         */
        hwif->acpidata->master.drive = &hwif->drives[0];
        hwif->drives[0].acpidata = &hwif->acpidata->master;
        master = &hwif->acpidata->master;

        hwif->acpidata->slave.drive = &hwif->drives[1];
        hwif->drives[1].acpidata = &hwif->acpidata->slave;
        slave = &hwif->acpidata->slave;


        /*
         * Send IDENTIFY for each drive
         */
        if (master->drive->present) {
                err = taskfile_lib_get_identify(master->drive, master->idbuff);
                if (err) {
                        DEBPRINT("identify device %s failed (%d)\n",
                                 master->drive->name, err);
                }
        }

        if (slave->drive->present) {
                err = taskfile_lib_get_identify(slave->drive, slave->idbuff);
                if (err) {
                        DEBPRINT("identify device %s failed (%d)\n",
                                 slave->drive->name, err);
                }
        }

        if (ide_noacpionboot) {
                DEBPRINT("ACPI methods disabled on boot\n");
                return;
        }

        /* ACPI _PS0 before _STM */
        ide_acpi_set_state(hwif, 1);
        /*
         * ACPI requires us to call _STM on startup
         */
        ide_acpi_get_timing(hwif);
        ide_acpi_push_timing(hwif);

        for (unit = 0; unit < MAX_DRIVES; ++unit) {
                ide_drive_t *drive = &hwif->drives[unit];

                if (drive->present) {
                        /* Execute ACPI startup code */
                        ide_acpi_exec_tfs(drive);
                }
        }
}
EXPORT_SYMBOL_GPL(ide_acpi_init);