pciex/hotplug/pciehpc_acpi.c

	pciehpc_acpi.c revision ed11b5015754f34571b1ea0fef3f0faad03a1e45
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 *  Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 *  Use is subject to license terms.
 */

/*
 * ACPI interface related functions used in PCIEHPC driver module.
 *
 * NOTE: This file is compiled and delivered through misc/pcie module.
 */

#include <sys/note.h>
#include <sys/conf.h>
#include <sys/kmem.h>
#include <sys/debug.h>
#include <sys/vtrace.h>
#include <sys/varargs.h>
#include <sys/ddi_impldefs.h>
#include <sys/pci.h>
#include <sys/ddi.h>
#include <sys/sunddi.h>
#include <sys/sunndi.h>
#include <sys/pci_impl.h>
#include <sys/pcie_acpi.h>
#include <sys/hotplug/pci/pcie_hp.h>
#include <sys/hotplug/pci/pciehpc_acpi.h>

/* local static functions */
static int pciehpc_acpi_hpc_init(pcie_hp_ctrl_t *ctrl_p);
static int pciehpc_acpi_hpc_uninit(pcie_hp_ctrl_t *ctrl_p);
static int pciehpc_acpi_slotinfo_init(pcie_hp_ctrl_t *ctrl_p);
static int pciehpc_acpi_slotinfo_uninit(pcie_hp_ctrl_t *ctrl_p);
static int pciehpc_acpi_enable_intr(pcie_hp_ctrl_t *ctrl_p);
static int pciehpc_acpi_disable_intr(pcie_hp_ctrl_t *ctrl_p);
static int pciehpc_acpi_slot_poweron(pcie_hp_slot_t *slot_p,
    ddi_hp_cn_state_t *result);
static int pciehpc_acpi_slot_poweroff(pcie_hp_slot_t *slot_p,
    ddi_hp_cn_state_t *result);
static void pciehpc_acpi_setup_ops(pcie_hp_ctrl_t *ctrl_p);

static ACPI_STATUS pciehpc_acpi_install_event_handler(pcie_hp_ctrl_t *ctrl_p);
static void pciehpc_acpi_uninstall_event_handler(pcie_hp_ctrl_t *ctrl_p);
static ACPI_STATUS pciehpc_acpi_power_on_slot(pcie_hp_ctrl_t *ctrl_p);
static ACPI_STATUS pciehpc_acpi_power_off_slot(pcie_hp_ctrl_t *ctrl_p);
static void pciehpc_acpi_notify_handler(ACPI_HANDLE device, uint32_t val,
    void *context);
static ACPI_STATUS pciehpc_acpi_get_dev_state(ACPI_HANDLE obj, int *statusp);

/*
 * Update ops vector with platform specific (ACPI, CK8-04,...) functions.
 */
void
pciehpc_update_ops(pcie_hp_ctrl_t *ctrl_p)
{
    boolean_t hp_native_mode = B_FALSE;
    uint32_t osc_flags = OSC_CONTROL_PCIE_NAT_HP;

    /*
     * Call _OSC method to determine if hotplug mode is native or ACPI.
     * If _OSC method succeeds hp_native_mode below will be set according to
     * if native hotplug control was granted or not by BIOS.
     *
     * If _OSC method fails for any reason or if native hotplug control was
     * not granted assume it's ACPI mode and update platform specific
     * (ACPI, CK8-04,...) impl. ops
     */

    if (pcie_acpi_osc(ctrl_p->hc_dip, &osc_flags) == DDI_SUCCESS) {
        hp_native_mode = (osc_flags & OSC_CONTROL_PCIE_NAT_HP) ?
            B_TRUE : B_FALSE;
    }

    if (!hp_native_mode) {
        pcie_bus_t *bus_p = PCIE_DIP2BUS(ctrl_p->hc_dip);

        /* update ops vector for ACPI mode */
        pciehpc_acpi_setup_ops(ctrl_p);
        bus_p->bus_hp_sup_modes |= PCIE_ACPI_HP_MODE;
        bus_p->bus_hp_curr_mode = PCIE_ACPI_HP_MODE;
    }
}

void
pciehpc_acpi_setup_ops(pcie_hp_ctrl_t *ctrl_p)
{
    ctrl_p->hc_ops.init_hpc_hw = pciehpc_acpi_hpc_init;
    ctrl_p->hc_ops.uninit_hpc_hw = pciehpc_acpi_hpc_uninit;
    ctrl_p->hc_ops.init_hpc_slotinfo = pciehpc_acpi_slotinfo_init;
    ctrl_p->hc_ops.uninit_hpc_slotinfo = pciehpc_acpi_slotinfo_uninit;
    ctrl_p->hc_ops.poweron_hpc_slot = pciehpc_acpi_slot_poweron;
    ctrl_p->hc_ops.poweroff_hpc_slot = pciehpc_acpi_slot_poweroff;
    ctrl_p->hc_ops.disable_hpc_intr = pciehpc_acpi_disable_intr;
    ctrl_p->hc_ops.enable_hpc_intr = pciehpc_acpi_enable_intr;
}

/*
 * Intialize hot plug control for ACPI mode.
 */
static int
pciehpc_acpi_hpc_init(pcie_hp_ctrl_t *ctrl_p)
{
    ACPI_HANDLE pcibus_obj;
    int status = AE_ERROR;
    ACPI_HANDLE slot_dev_obj;
    ACPI_HANDLE hdl;
    pciehpc_acpi_t *acpi_p;
    uint16_t bus_methods = 0;
    uint16_t slot_methods = 0;

    /* get the ACPI object for the bus node */
    status = acpica_get_handle(ctrl_p->hc_dip, &pcibus_obj);
    if (status != AE_OK)
        return (DDI_FAILURE);

    /* get the ACPI object handle for the child node */
    status = AcpiGetNextObject(ACPI_TYPE_DEVICE, pcibus_obj,
        NULL, &slot_dev_obj);
    if (status != AE_OK) {
        PCIE_DBG("pciehpc_acpi_hpc_init: Get ACPI object failed\n");
        return (DDI_FAILURE);
    }

    /*
     * gather the info about the ACPI methods present on the bus node
     * and the child nodes.
     */
    if (AcpiGetHandle(pcibus_obj, "_OSC", &hdl) == AE_OK)
        bus_methods |= PCIEHPC_ACPI_OSC_PRESENT;
    if (AcpiGetHandle(pcibus_obj, "_OSHP", &hdl) == AE_OK)
        bus_methods |= PCIEHPC_ACPI_OSHP_PRESENT;
    if (AcpiGetHandle(pcibus_obj, "_HPX", &hdl) == AE_OK)
        bus_methods |= PCIEHPC_ACPI_HPX_PRESENT;
    if (AcpiGetHandle(pcibus_obj, "_HPP", &hdl) == AE_OK)
        bus_methods |= PCIEHPC_ACPI_HPP_PRESENT;
    if (AcpiGetHandle(pcibus_obj, "_DSM", &hdl) == AE_OK)
        bus_methods |= PCIEHPC_ACPI_DSM_PRESENT;
    if (AcpiGetHandle(slot_dev_obj, "_SUN", &hdl) == AE_OK)
        slot_methods |= PCIEHPC_ACPI_SUN_PRESENT;
    if (AcpiGetHandle(slot_dev_obj, "_PS0", &hdl) == AE_OK)
        slot_methods |= PCIEHPC_ACPI_PS0_PRESENT;
    if (AcpiGetHandle(slot_dev_obj, "_EJ0", &hdl) == AE_OK)
        slot_methods |= PCIEHPC_ACPI_EJ0_PRESENT;
    if (AcpiGetHandle(slot_dev_obj, "_STA", &hdl) == AE_OK)
        slot_methods |= PCIEHPC_ACPI_STA_PRESENT;

    /* save ACPI object handles, etc. */
    acpi_p = kmem_zalloc(sizeof (pciehpc_acpi_t), KM_SLEEP);
    acpi_p->bus_obj = pcibus_obj;
    acpi_p->slot_dev_obj = slot_dev_obj;
    acpi_p->bus_methods = bus_methods;
    acpi_p->slot_methods = slot_methods;
    ctrl_p->hc_misc_data = acpi_p;

    return (DDI_SUCCESS);
}

/*
 * Uninitialize HPC.
 */
static int
pciehpc_acpi_hpc_uninit(pcie_hp_ctrl_t *ctrl_p)
{
    /* free up buffer used for misc_data */
    if (ctrl_p->hc_misc_data) {
        kmem_free(ctrl_p->hc_misc_data, sizeof (pciehpc_acpi_t));
        ctrl_p->hc_misc_data = NULL;
    }

    return (DDI_SUCCESS);
}

/*
 * Enable interrupts. For ACPI hot plug this is a NOP.
 * Just return DDI_SUCCESS.
 */
/*ARGSUSED*/
static int
pciehpc_acpi_enable_intr(pcie_hp_ctrl_t *ctrl_p)
{
    return (DDI_SUCCESS);
}

/*
 * Disable interrupts. For ACPI hot plug this is a NOP.
 * Just return DDI_SUCCESS.
 */
/*ARGSUSED*/
static int
pciehpc_acpi_disable_intr(pcie_hp_ctrl_t *ctrl_p)
{
    return (DDI_SUCCESS);
}

/*
 * This function is similar to pciehpc_slotinfo_init() with some
 * changes:
 *  - no need for kernel thread to handle ATTN button events
 *  - function ops for connect/disconnect are different
 *
 * ASSUMPTION: No conflict in doing reads to HP registers directly.
 * Otherwise, there are no ACPI interfaces to do LED control or to get
 * the hot plug capabilities (ATTN button, MRL, etc.).
 */
static int
pciehpc_acpi_slotinfo_init(pcie_hp_ctrl_t *ctrl_p)
{
    uint32_t    slot_capabilities;
    pcie_hp_slot_t  *slot_p = ctrl_p->hc_slots[0];
    pcie_bus_t  *bus_p = PCIE_DIP2BUS(ctrl_p->hc_dip);

    mutex_enter(&ctrl_p->hc_mutex);
    /*
     * setup DDI HP framework slot information structure
     */
    slot_p->hs_device_num = 0;
    slot_p->hs_info.cn_type = DDI_HP_CN_TYPE_PCIE;
    slot_p->hs_info.cn_type_str = PCIE_ACPI_HP_TYPE;
    slot_p->hs_info.cn_child = NULL;

    slot_p->hs_minor =
        PCI_MINOR_NUM(ddi_get_instance(ctrl_p->hc_dip),
        slot_p->hs_device_num);

    /* read Slot Capabilities Register */
    slot_capabilities = pciehpc_reg_get32(ctrl_p,
        bus_p->bus_pcie_off + PCIE_SLOTCAP);

    /* setup slot number/name */
    pciehpc_set_slot_name(ctrl_p);

    /* check if Attn Button present */
    ctrl_p->hc_has_attn = (slot_capabilities &
        PCIE_SLOTCAP_ATTN_BUTTON) ? B_TRUE : B_FALSE;

    /* check if Manual Retention Latch sensor present */
    ctrl_p->hc_has_mrl = (slot_capabilities & PCIE_SLOTCAP_MRL_SENSOR) ?
        B_TRUE : B_FALSE;

    /*
     * PCI-E (draft) version 1.1 defines EMI Lock Present bit
     * in Slot Capabilities register. Check for it.
     */
    ctrl_p->hc_has_emi_lock = (slot_capabilities &
        PCIE_SLOTCAP_EMI_LOCK_PRESENT) ? B_TRUE : B_FALSE;

    /* get current slot state from the hw */
    pciehpc_get_slot_state(slot_p);
    if (slot_p->hs_info.cn_state >= DDI_HP_CN_STATE_ENABLED)
        slot_p->hs_condition = AP_COND_OK;

    mutex_exit(&ctrl_p->hc_mutex);

    /* setup Notify() handler for hot plug events from ACPI BIOS */
    if (pciehpc_acpi_install_event_handler(ctrl_p) != AE_OK)
        return (DDI_FAILURE);

    PCIE_DBG("ACPI hot plug is enabled for slot #%d\n",
        slot_p->hs_phy_slot_num);

    return (DDI_SUCCESS);
}

/*
 * This function is similar to pciehcp_slotinfo_uninit() but has ACPI
 * specific cleanup.
 */
static int
pciehpc_acpi_slotinfo_uninit(pcie_hp_ctrl_t *ctrl_p)
{
    pcie_hp_slot_t *slot_p = ctrl_p->hc_slots[0];

    /* uninstall Notify() event handler */
    pciehpc_acpi_uninstall_event_handler(ctrl_p);
    if (slot_p->hs_info.cn_name)
        kmem_free(slot_p->hs_info.cn_name,
            strlen(slot_p->hs_info.cn_name) + 1);

    return (DDI_SUCCESS);
}

/*
 * This function is same as pciehpc_slot_poweron() except that it
 * uses ACPI method PS0 to enable power to the slot. If no PS0 method
 * is present then it returns DDI_FAILURE.
 */
/*ARGSUSED*/
static int
pciehpc_acpi_slot_poweron(pcie_hp_slot_t *slot_p, ddi_hp_cn_state_t *result)
{
    pcie_hp_ctrl_t  *ctrl_p = slot_p->hs_ctrl;
    pcie_bus_t  *bus_p = PCIE_DIP2BUS(ctrl_p->hc_dip);
    uint16_t    status, control;

    ASSERT(MUTEX_HELD(&ctrl_p->hc_mutex));

    /* get the current state of the slot */
    pciehpc_get_slot_state(slot_p);

    /* check if the slot is already in the 'ENABLED' state */
    if (slot_p->hs_info.cn_state == DDI_HP_CN_STATE_ENABLED) {
        /* slot is already in the 'connected' state */
        PCIE_DBG("slot %d already connected\n",
            slot_p->hs_phy_slot_num);

        *result = slot_p->hs_info.cn_state;
        return (DDI_SUCCESS);
    }

    /* read the Slot Status Register */
    status =  pciehpc_reg_get16(ctrl_p,
        bus_p->bus_pcie_off + PCIE_SLOTSTS);

    /* make sure the MRL switch is closed if present */
    if ((ctrl_p->hc_has_mrl) && (status & PCIE_SLOTSTS_MRL_SENSOR_OPEN)) {
        /* MRL switch is open */
        cmn_err(CE_WARN, "MRL switch is open on slot %d",
            slot_p->hs_phy_slot_num);
        goto cleanup;
    }

    /* make sure the slot has a device present */
    if (!(status & PCIE_SLOTSTS_PRESENCE_DETECTED)) {
        /* slot is empty */
        PCIE_DBG("slot %d is empty\n", slot_p->hs_phy_slot_num);
        goto cleanup;
    }

    /* get the current state of Slot Control Register */
    control =  pciehpc_reg_get16(ctrl_p,
        bus_p->bus_pcie_off + PCIE_SLOTCTL);

    /* check if the slot's power state is ON */
    if (!(control & PCIE_SLOTCTL_PWR_CONTROL)) {
        /* slot is already powered up */
        PCIE_DBG("slot %d already connected\n",
            slot_p->hs_phy_slot_num);

        *result = slot_p->hs_info.cn_state;
        return (DDI_SUCCESS);
    }

    /* turn on power to the slot using ACPI method (PS0) */
    if (pciehpc_acpi_power_on_slot(ctrl_p) != AE_OK)
        goto cleanup;

    *result = slot_p->hs_info.cn_state = DDI_HP_CN_STATE_POWERED;
    return (DDI_SUCCESS);

cleanup:
    return (DDI_FAILURE);
}

/*
 * This function is same as pciehpc_slot_poweroff() except that it
 * uses ACPI method EJ0 to disable power to the slot. If no EJ0 method
 * is present then it returns DDI_FAILURE.
 */
/*ARGSUSED*/
static int
pciehpc_acpi_slot_poweroff(pcie_hp_slot_t *slot_p, ddi_hp_cn_state_t *result)
{
    pcie_hp_ctrl_t  *ctrl_p = slot_p->hs_ctrl;
    pcie_bus_t  *bus_p = PCIE_DIP2BUS(ctrl_p->hc_dip);
    uint16_t    status;

    ASSERT(MUTEX_HELD(&ctrl_p->hc_mutex));

    /* get the current state of the slot */
    pciehpc_get_slot_state(slot_p);

    /* check if the slot is already in the state less than 'powered' */
    if (slot_p->hs_info.cn_state < DDI_HP_CN_STATE_POWERED) {
        /* slot is in the 'disconnected' state */
        PCIE_DBG("slot %d already disconnected\n",
            slot_p->hs_phy_slot_num);
        ASSERT(slot_p->hs_power_led_state == PCIE_HP_LED_OFF);

        *result = slot_p->hs_info.cn_state;
        return (DDI_SUCCESS);
    }

    /* read the Slot Status Register */
    status =  pciehpc_reg_get16(ctrl_p,
        bus_p->bus_pcie_off + PCIE_SLOTSTS);

    /* make sure the slot has a device present */
    if (!(status & PCIE_SLOTSTS_PRESENCE_DETECTED)) {
        /* slot is empty */
        PCIE_DBG("slot %d is empty", slot_p->hs_phy_slot_num);
        goto cleanup;
    }

    /* turn off power to the slot using ACPI method (EJ0) */
    if (pciehpc_acpi_power_off_slot(ctrl_p) != AE_OK)
        goto cleanup;

    /* get the current state of the slot */
    pciehpc_get_slot_state(slot_p);

    *result = slot_p->hs_info.cn_state;

    return (DDI_SUCCESS);

cleanup:
    return (DDI_FAILURE);
}

/*
 * Install event handler for the hot plug events on the bus node as well
 * as device function (dev=0,func=0).
 */
static ACPI_STATUS
pciehpc_acpi_install_event_handler(pcie_hp_ctrl_t *ctrl_p)
{
    pcie_hp_slot_t *slot_p = ctrl_p->hc_slots[0];
    int status = AE_OK;
    pciehpc_acpi_t *acpi_p;

    PCIE_DBG("install event handler for slot %d\n",
        slot_p->hs_phy_slot_num);
    acpi_p = ctrl_p->hc_misc_data;
    if (acpi_p->slot_dev_obj == NULL)
        return (AE_NOT_FOUND);

    /*
     * Install event hanlder for events on the bus object.
     * (Note: Insert event (hot-insert) is delivered on this object)
     */
    status = AcpiInstallNotifyHandler(acpi_p->slot_dev_obj,
        ACPI_SYSTEM_NOTIFY, pciehpc_acpi_notify_handler, (void *)ctrl_p);
    if (status != AE_OK)
        goto cleanup;

    /*
     * Install event hanlder for events on the device function object.
     * (Note: Eject device event (hot-remove) is delivered on this object)
     *
     * NOTE: Here the assumption is that Notify events are delivered
     * on all of the 8 possible device functions so, subscribing to
     * one of them is sufficient.
     */
    status = AcpiInstallNotifyHandler(acpi_p->bus_obj,
        ACPI_SYSTEM_NOTIFY, pciehpc_acpi_notify_handler, (void *)ctrl_p);
    return (status);

cleanup:
    (void) AcpiRemoveNotifyHandler(acpi_p->slot_dev_obj,
        ACPI_SYSTEM_NOTIFY, pciehpc_acpi_notify_handler);
    return (status);
}

/*ARGSUSED*/
static void
pciehpc_acpi_notify_handler(ACPI_HANDLE device, uint32_t val, void *context)
{
    pcie_hp_ctrl_t *ctrl_p = context;
    pcie_hp_slot_t *slot_p = ctrl_p->hc_slots[0];
    pciehpc_acpi_t *acpi_p;
    ddi_hp_cn_state_t curr_state;
    int dev_state = 0;

    PCIE_DBG("received Notify(%d) event on slot #%d\n",
        val, slot_p->hs_phy_slot_num);

    mutex_enter(&ctrl_p->hc_mutex);

    /*
     * get the state of the device (from _STA method)
     */
    acpi_p = ctrl_p->hc_misc_data;
    if (pciehpc_acpi_get_dev_state(acpi_p->slot_dev_obj,
        &dev_state) != AE_OK) {
        cmn_err(CE_WARN, "failed to get device status on slot %d",
            slot_p->hs_phy_slot_num);
    }
    PCIE_DBG("(1)device state on slot #%d: 0x%x\n",
        slot_p->hs_phy_slot_num, dev_state);

    curr_state = slot_p->hs_info.cn_state;
    pciehpc_get_slot_state(slot_p);

    switch (val) {
    case 0: /* (re)enumerate the device */
    case 3: /* Request Eject */
    {
        ddi_hp_cn_state_t target_state;

        /*
         * Ignore the event if ATTN button is not present (ACPI BIOS
         * problem).
         *
         * NOTE: This situation has been observed on some platforms
         * where the ACPI BIOS is generating the event for some other
         * (non hot-plug) operations (bug).
         */
        if (ctrl_p->hc_has_attn == B_FALSE) {
            PCIE_DBG("Ignore the unexpected event "
                "on slot #%d (state 0x%x)",
                slot_p->hs_phy_slot_num, dev_state);
            break;
        }

        /* send the event to DDI Hotplug framework */
        if (curr_state < DDI_HP_CN_STATE_POWERED) {
            /* Insertion. Upgrade state to ENABLED */
            target_state = DDI_HP_CN_STATE_ENABLED;

            /*
             * When pressing ATTN button to enable a card, the slot
             * could be powered. Keep the slot state on PWOERED
             * other than ENABLED.
             */
            if (slot_p->hs_info.cn_state == DDI_HP_CN_STATE_ENABLED)
                slot_p->hs_info.cn_state =
                    DDI_HP_CN_STATE_POWERED;
        } else {
            /* Want to remove; Power off Connection */
            target_state = DDI_HP_CN_STATE_EMPTY;
        }

        (void) ndi_hp_state_change_req(slot_p->hs_ctrl->hc_dip,
            slot_p->hs_info.cn_name,
            target_state, DDI_HP_REQ_ASYNC);

        break;
    }
    default:
        cmn_err(CE_NOTE, "Unknown Notify() event %d on slot #%d\n",
            val, slot_p->hs_phy_slot_num);
        break;
    }
    mutex_exit(&ctrl_p->hc_mutex);
}

static void
pciehpc_acpi_uninstall_event_handler(pcie_hp_ctrl_t *ctrl_p)
{
    pciehpc_acpi_t *acpi_p = ctrl_p->hc_misc_data;
    pcie_hp_slot_t *slot_p = ctrl_p->hc_slots[0];

    PCIE_DBG("Uninstall event handler for slot #%d\n",
        slot_p->hs_phy_slot_num);
    (void) AcpiRemoveNotifyHandler(acpi_p->slot_dev_obj,
        ACPI_SYSTEM_NOTIFY, pciehpc_acpi_notify_handler);
    (void) AcpiRemoveNotifyHandler(acpi_p->bus_obj,
        ACPI_SYSTEM_NOTIFY, pciehpc_acpi_notify_handler);
}

/*
 * Run _PS0 method to turn on power to the slot.
 */
static ACPI_STATUS
pciehpc_acpi_power_on_slot(pcie_hp_ctrl_t *ctrl_p)
{
    int status = AE_OK;
    pciehpc_acpi_t *acpi_p = ctrl_p->hc_misc_data;
    int dev_state = 0;
    pcie_hp_slot_t *slot_p = ctrl_p->hc_slots[0];

    PCIE_DBG("turn ON power to the slot #%d\n", slot_p->hs_phy_slot_num);

    status = AcpiEvaluateObject(acpi_p->slot_dev_obj, "_PS0", NULL, NULL);

    /* get the state of the device (from _STA method) */
    if (status == AE_OK) {
        if (pciehpc_acpi_get_dev_state(acpi_p->slot_dev_obj,
            &dev_state) != AE_OK)
            cmn_err(CE_WARN, "failed to get device status "
                "on slot #%d", slot_p->hs_phy_slot_num);
    }

    PCIE_DBG("(3)device state on slot #%d: 0x%x\n",
        slot_p->hs_phy_slot_num, dev_state);

    pciehpc_get_slot_state(slot_p);

    if (slot_p->hs_info.cn_state < DDI_HP_CN_STATE_POWERED) {
        cmn_err(CE_WARN, "failed to power on the slot #%d"
            "(dev_state 0x%x, ACPI_STATUS 0x%x)",
            slot_p->hs_phy_slot_num, dev_state, status);
        return (AE_ERROR);
    }

    return (status);
}

/*
 * Run _EJ0 method to turn off power to the slot.
 */
static ACPI_STATUS
pciehpc_acpi_power_off_slot(pcie_hp_ctrl_t *ctrl_p)
{
    int status = AE_OK;
    pciehpc_acpi_t *acpi_p = ctrl_p->hc_misc_data;
    int dev_state = 0;
    pcie_hp_slot_t *slot_p = ctrl_p->hc_slots[0];

    PCIE_DBG("turn OFF power to the slot #%d\n", slot_p->hs_phy_slot_num);

    status = AcpiEvaluateObject(acpi_p->slot_dev_obj, "_EJ0", NULL, NULL);

    /* get the state of the device (from _STA method) */
    if (status == AE_OK) {
        if (pciehpc_acpi_get_dev_state(acpi_p->slot_dev_obj,
            &dev_state) != AE_OK)
            cmn_err(CE_WARN, "failed to get device status "
                "on slot #%d", slot_p->hs_phy_slot_num);
    }

    PCIE_DBG("(2)device state on slot #%d: 0x%x\n",
        slot_p->hs_phy_slot_num, dev_state);

    pciehpc_get_slot_state(slot_p);

    if (slot_p->hs_info.cn_state >= DDI_HP_CN_STATE_POWERED) {
        cmn_err(CE_WARN, "failed to power OFF the slot #%d"
            "(dev_state 0x%x, ACPI_STATUS 0x%x)",
            slot_p->hs_phy_slot_num, dev_state, status);
        return (AE_ERROR);
    }

    return (status);
}

/*
 * Get the status info (as returned by _STA method) for the device.
 */
static ACPI_STATUS
pciehpc_acpi_get_dev_state(ACPI_HANDLE obj, int *statusp)
{
    ACPI_DEVICE_INFO *info;
    int ret = AE_OK;

    /*
     * Get device info object
     */
    if ((ret = AcpiGetObjectInfo(obj, &info)) != AE_OK)
        return (ret);

    if (info->Valid & ACPI_VALID_STA) {
        *statusp = info->CurrentStatus;
    } else {
        /*
         * no _STA present; assume the device status is normal
         * (i.e present, enabled, shown in UI and functioning).
         * See section 6.3.7 of ACPI 3.0 spec.
         */
        *statusp = STATUS_NORMAL;
    }

    AcpiOsFree(info);

    return (ret);
}