/*
 * Copyright 2012 Advanced Micro Devices, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 *
 */

#include <linux/pci.h>
#include <linux/acpi.h>
#include <linux/slab.h>
#include <linux/power_supply.h>
#include <linux/vga_switcheroo.h>
#include <acpi/video.h>
#include <drm/drmP.h>
#include <drm/drm_crtc_helper.h>
#include "radeon.h"
#include "radeon_acpi.h"
#include "atom.h"

#define ACPI_AC_CLASS           "ac_adapter"

extern void radeon_pm_acpi_event_handler(struct radeon_device *rdev);

struct atif_verify_interface {
        u16 size;               /* structure size in bytes (includes size field) */
        u16 version;            /* version */
        u32 notification_mask;  /* supported notifications mask */
        u32 function_bits;      /* supported functions bit vector */
} __packed;

struct atif_system_params {
        u16 size;               /* structure size in bytes (includes size field) */
        u32 valid_mask;         /* valid flags mask */
        u32 flags;              /* flags */
        u8 command_code;        /* notify command code */
} __packed;

struct atif_sbios_requests {
        u16 size;               /* structure size in bytes (includes size field) */
        u32 pending;            /* pending sbios requests */
        u8 panel_exp_mode;      /* panel expansion mode */
        u8 thermal_gfx;         /* thermal state: target gfx controller */
        u8 thermal_state;       /* thermal state: state id (0: exit state, non-0: state) */
        u8 forced_power_gfx;    /* forced power state: target gfx controller */
        u8 forced_power_state;  /* forced power state: state id */
        u8 system_power_src;    /* system power source */
        u8 backlight_level;     /* panel backlight level (0-255) */
} __packed;

#define ATIF_NOTIFY_MASK        0x3
#define ATIF_NOTIFY_NONE        0
#define ATIF_NOTIFY_81          1
#define ATIF_NOTIFY_N           2

struct atcs_verify_interface {
        u16 size;               /* structure size in bytes (includes size field) */
        u16 version;            /* version */
        u32 function_bits;      /* supported functions bit vector */
} __packed;

#define ATCS_VALID_FLAGS_MASK   0x3

struct atcs_pref_req_input {
        u16 size;               /* structure size in bytes (includes size field) */
        u16 client_id;          /* client id (bit 2-0: func num, 7-3: dev num, 15-8: bus num) */
        u16 valid_flags_mask;   /* valid flags mask */
        u16 flags;              /* flags */
        u8 req_type;            /* request type */
        u8 perf_req;            /* performance request */
} __packed;

struct atcs_pref_req_output {
        u16 size;               /* structure size in bytes (includes size field) */
        u8 ret_val;             /* return value */
} __packed;

/* Call the ATIF method
 */
/**
 * radeon_atif_call - call an ATIF method
 *
 * @handle: acpi handle
 * @function: the ATIF function to execute
 * @params: ATIF function params
 *
 * Executes the requested ATIF function (all asics).
 * Returns a pointer to the acpi output buffer.
 */
static union acpi_object *radeon_atif_call(acpi_handle handle, int function,
                struct acpi_buffer *params)
{
        acpi_status status;
        union acpi_object atif_arg_elements[2];
        struct acpi_object_list atif_arg;
        struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };

        atif_arg.count = 2;
        atif_arg.pointer = &atif_arg_elements[0];

        atif_arg_elements[0].type = ACPI_TYPE_INTEGER;
        atif_arg_elements[0].integer.value = function;

        if (params) {
                atif_arg_elements[1].type = ACPI_TYPE_BUFFER;
                atif_arg_elements[1].buffer.length = params->length;
                atif_arg_elements[1].buffer.pointer = params->pointer;
        } else {
                /* We need a second fake parameter */
                atif_arg_elements[1].type = ACPI_TYPE_INTEGER;
                atif_arg_elements[1].integer.value = 0;
        }

        status = acpi_evaluate_object(handle, "ATIF", &atif_arg, &buffer);

        /* Fail only if calling the method fails and ATIF is supported */
        if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
                DRM_DEBUG_DRIVER("failed to evaluate ATIF got %s\n",
                                 acpi_format_exception(status));
                kfree(buffer.pointer);
                return NULL;
        }

        return buffer.pointer;
}

/**
 * radeon_atif_parse_notification - parse supported notifications
 *
 * @n: supported notifications struct
 * @mask: supported notifications mask from ATIF
 *
 * Use the supported notifications mask from ATIF function
 * ATIF_FUNCTION_VERIFY_INTERFACE to determine what notifications
 * are supported (all asics).
 */
static void radeon_atif_parse_notification(struct radeon_atif_notifications *n, u32 mask)
{
        n->display_switch = mask & ATIF_DISPLAY_SWITCH_REQUEST_SUPPORTED;
        n->expansion_mode_change = mask & ATIF_EXPANSION_MODE_CHANGE_REQUEST_SUPPORTED;
        n->thermal_state = mask & ATIF_THERMAL_STATE_CHANGE_REQUEST_SUPPORTED;
        n->forced_power_state = mask & ATIF_FORCED_POWER_STATE_CHANGE_REQUEST_SUPPORTED;
        n->system_power_state = mask & ATIF_SYSTEM_POWER_SOURCE_CHANGE_REQUEST_SUPPORTED;
        n->display_conf_change = mask & ATIF_DISPLAY_CONF_CHANGE_REQUEST_SUPPORTED;
        n->px_gfx_switch = mask & ATIF_PX_GFX_SWITCH_REQUEST_SUPPORTED;
        n->brightness_change = mask & ATIF_PANEL_BRIGHTNESS_CHANGE_REQUEST_SUPPORTED;
        n->dgpu_display_event = mask & ATIF_DGPU_DISPLAY_EVENT_SUPPORTED;
}

/**
 * radeon_atif_parse_functions - parse supported functions
 *
 * @f: supported functions struct
 * @mask: supported functions mask from ATIF
 *
 * Use the supported functions mask from ATIF function
 * ATIF_FUNCTION_VERIFY_INTERFACE to determine what functions
 * are supported (all asics).
 */
static void radeon_atif_parse_functions(struct radeon_atif_functions *f, u32 mask)
{
        f->system_params = mask & ATIF_GET_SYSTEM_PARAMETERS_SUPPORTED;
        f->sbios_requests = mask & ATIF_GET_SYSTEM_BIOS_REQUESTS_SUPPORTED;
        f->select_active_disp = mask & ATIF_SELECT_ACTIVE_DISPLAYS_SUPPORTED;
        f->lid_state = mask & ATIF_GET_LID_STATE_SUPPORTED;
        f->get_tv_standard = mask & ATIF_GET_TV_STANDARD_FROM_CMOS_SUPPORTED;
        f->set_tv_standard = mask & ATIF_SET_TV_STANDARD_IN_CMOS_SUPPORTED;
        f->get_panel_expansion_mode = mask & ATIF_GET_PANEL_EXPANSION_MODE_FROM_CMOS_SUPPORTED;
        f->set_panel_expansion_mode = mask & ATIF_SET_PANEL_EXPANSION_MODE_IN_CMOS_SUPPORTED;
        f->temperature_change = mask & ATIF_TEMPERATURE_CHANGE_NOTIFICATION_SUPPORTED;
        f->graphics_device_types = mask & ATIF_GET_GRAPHICS_DEVICE_TYPES_SUPPORTED;
}

/**
 * radeon_atif_verify_interface - verify ATIF
 *
 * @handle: acpi handle
 * @atif: radeon atif struct
 *
 * Execute the ATIF_FUNCTION_VERIFY_INTERFACE ATIF function
 * to initialize ATIF and determine what features are supported
 * (all asics).
 * returns 0 on success, error on failure.
 */
static int radeon_atif_verify_interface(acpi_handle handle,
                struct radeon_atif *atif)
{
        union acpi_object *info;
        struct atif_verify_interface output;
        size_t size;
        int err = 0;

        info = radeon_atif_call(handle, ATIF_FUNCTION_VERIFY_INTERFACE, NULL);
        if (!info)
                return -EIO;

        memset(&output, 0, sizeof(output));

        size = *(u16 *) info->buffer.pointer;
        if (size < 12) {
                DRM_INFO("ATIF buffer is too small: %zu\n", size);
                err = -EINVAL;
                goto out;
        }
        size = min(sizeof(output), size);

        memcpy(&output, info->buffer.pointer, size);

        /* TODO: check version? */
        DRM_DEBUG_DRIVER("ATIF version %u\n", output.version);

        radeon_atif_parse_notification(&atif->notifications, output.notification_mask);
        radeon_atif_parse_functions(&atif->functions, output.function_bits);

out:
        kfree(info);
        return err;
}

/**
 * radeon_atif_get_notification_params - determine notify configuration
 *
 * @handle: acpi handle
 * @n: atif notification configuration struct
 *
 * Execute the ATIF_FUNCTION_GET_SYSTEM_PARAMETERS ATIF function
 * to determine if a notifier is used and if so which one
 * (all asics).  This is either Notify(VGA, 0x81) or Notify(VGA, n)
 * where n is specified in the result if a notifier is used.
 * Returns 0 on success, error on failure.
 */
static int radeon_atif_get_notification_params(acpi_handle handle,
                struct radeon_atif_notification_cfg *n)
{
        union acpi_object *info;
        struct atif_system_params params;
        size_t size;
        int err = 0;

        info = radeon_atif_call(handle, ATIF_FUNCTION_GET_SYSTEM_PARAMETERS, NULL);
        if (!info) {
                err = -EIO;
                goto out;
        }

        size = *(u16 *) info->buffer.pointer;
        if (size < 10) {
                err = -EINVAL;
                goto out;
        }

        memset(&params, 0, sizeof(params));
        size = min(sizeof(params), size);
        memcpy(&params, info->buffer.pointer, size);

        DRM_DEBUG_DRIVER("SYSTEM_PARAMS: mask = %#x, flags = %#x\n",
                        params.flags, params.valid_mask);
        params.flags = params.flags & params.valid_mask;

        if ((params.flags & ATIF_NOTIFY_MASK) == ATIF_NOTIFY_NONE) {
                n->enabled = false;
                n->command_code = 0;
        } else if ((params.flags & ATIF_NOTIFY_MASK) == ATIF_NOTIFY_81) {
                n->enabled = true;
                n->command_code = 0x81;
        } else {
                if (size < 11) {
                        err = -EINVAL;
                        goto out;
                }
                n->enabled = true;
                n->command_code = params.command_code;
        }

out:
        DRM_DEBUG_DRIVER("Notification %s, command code = %#x\n",
                        (n->enabled ? "enabled" : "disabled"),
                        n->command_code);
        kfree(info);
        return err;
}

/**
 * radeon_atif_get_sbios_requests - get requested sbios event
 *
 * @handle: acpi handle
 * @req: atif sbios request struct
 *
 * Execute the ATIF_FUNCTION_GET_SYSTEM_BIOS_REQUESTS ATIF function
 * to determine what requests the sbios is making to the driver
 * (all asics).
 * Returns 0 on success, error on failure.
 */
static int radeon_atif_get_sbios_requests(acpi_handle handle,
                struct atif_sbios_requests *req)
{
        union acpi_object *info;
        size_t size;
        int count = 0;

        info = radeon_atif_call(handle, ATIF_FUNCTION_GET_SYSTEM_BIOS_REQUESTS, NULL);
        if (!info)
                return -EIO;

        size = *(u16 *)info->buffer.pointer;
        if (size < 0xd) {
                count = -EINVAL;
                goto out;
        }
        memset(req, 0, sizeof(*req));

        size = min(sizeof(*req), size);
        memcpy(req, info->buffer.pointer, size);
        DRM_DEBUG_DRIVER("SBIOS pending requests: %#x\n", req->pending);

        count = hweight32(req->pending);

out:
        kfree(info);
        return count;
}

/**
 * radeon_atif_handler - handle ATIF notify requests
 *
 * @rdev: radeon_device pointer
 * @event: atif sbios request struct
 *
 * Checks the acpi event and if it matches an atif event,
 * handles it.
 * Returns NOTIFY code
 */
int radeon_atif_handler(struct radeon_device *rdev,
                struct acpi_bus_event *event)
{
        struct radeon_atif *atif = &rdev->atif;
        struct atif_sbios_requests req;
        acpi_handle handle;
        int count;

        DRM_DEBUG_DRIVER("event, device_class = %s, type = %#x\n",
                        event->device_class, event->type);

        if (strcmp(event->device_class, ACPI_VIDEO_CLASS) != 0)
                return NOTIFY_DONE;

        if (!atif->notification_cfg.enabled ||
                        event->type != atif->notification_cfg.command_code)
                /* Not our event */
                return NOTIFY_DONE;

        /* Check pending SBIOS requests */
        handle = ACPI_HANDLE(&rdev->pdev->dev);
        count = radeon_atif_get_sbios_requests(handle, &req);

        if (count <= 0)
                return NOTIFY_DONE;

        DRM_DEBUG_DRIVER("ATIF: %d pending SBIOS requests\n", count);

        if (req.pending & ATIF_PANEL_BRIGHTNESS_CHANGE_REQUEST) {
                struct radeon_encoder *enc = atif->encoder_for_bl;

                if (enc) {
                        DRM_DEBUG_DRIVER("Changing brightness to %d\n",
                                        req.backlight_level);

                        radeon_set_backlight_level(rdev, enc, req.backlight_level);

#if defined(CONFIG_BACKLIGHT_CLASS_DEVICE) || defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE)
                        if (rdev->is_atom_bios) {
                                struct radeon_encoder_atom_dig *dig = enc->enc_priv;
                                backlight_force_update(dig->bl_dev,
                                                       BACKLIGHT_UPDATE_HOTKEY);
                        } else {
                                struct radeon_encoder_lvds *dig = enc->enc_priv;
                                backlight_force_update(dig->bl_dev,
                                                       BACKLIGHT_UPDATE_HOTKEY);
                        }
#endif
                }
        }
        /* TODO: check other events */

        /* We've handled the event, stop the notifier chain. The ACPI interface
         * overloads ACPI_VIDEO_NOTIFY_PROBE, we don't want to send that to
         * userspace if the event was generated only to signal a SBIOS
         * request.
         */
        return NOTIFY_BAD;
}

/* Call the ATCS method
 */
/**
 * radeon_atcs_call - call an ATCS method
 *
 * @handle: acpi handle
 * @function: the ATCS function to execute
 * @params: ATCS function params
 *
 * Executes the requested ATCS function (all asics).
 * Returns a pointer to the acpi output buffer.
 */
static union acpi_object *radeon_atcs_call(acpi_handle handle, int function,
                                           struct acpi_buffer *params)
{
        acpi_status status;
        union acpi_object atcs_arg_elements[2];
        struct acpi_object_list atcs_arg;
        struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };

        atcs_arg.count = 2;
        atcs_arg.pointer = &atcs_arg_elements[0];

        atcs_arg_elements[0].type = ACPI_TYPE_INTEGER;
        atcs_arg_elements[0].integer.value = function;

        if (params) {
                atcs_arg_elements[1].type = ACPI_TYPE_BUFFER;
                atcs_arg_elements[1].buffer.length = params->length;
                atcs_arg_elements[1].buffer.pointer = params->pointer;
        } else {
                /* We need a second fake parameter */
                atcs_arg_elements[1].type = ACPI_TYPE_INTEGER;
                atcs_arg_elements[1].integer.value = 0;
        }

        status = acpi_evaluate_object(handle, "ATCS", &atcs_arg, &buffer);

        /* Fail only if calling the method fails and ATIF is supported */
        if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
                DRM_DEBUG_DRIVER("failed to evaluate ATCS got %s\n",
                                 acpi_format_exception(status));
                kfree(buffer.pointer);
                return NULL;
        }

        return buffer.pointer;
}

/**
 * radeon_atcs_parse_functions - parse supported functions
 *
 * @f: supported functions struct
 * @mask: supported functions mask from ATCS
 *
 * Use the supported functions mask from ATCS function
 * ATCS_FUNCTION_VERIFY_INTERFACE to determine what functions
 * are supported (all asics).
 */
static void radeon_atcs_parse_functions(struct radeon_atcs_functions *f, u32 mask)
{
        f->get_ext_state = mask & ATCS_GET_EXTERNAL_STATE_SUPPORTED;
        f->pcie_perf_req = mask & ATCS_PCIE_PERFORMANCE_REQUEST_SUPPORTED;
        f->pcie_dev_rdy = mask & ATCS_PCIE_DEVICE_READY_NOTIFICATION_SUPPORTED;
        f->pcie_bus_width = mask & ATCS_SET_PCIE_BUS_WIDTH_SUPPORTED;
}

/**
 * radeon_atcs_verify_interface - verify ATCS
 *
 * @handle: acpi handle
 * @atcs: radeon atcs struct
 *
 * Execute the ATCS_FUNCTION_VERIFY_INTERFACE ATCS function
 * to initialize ATCS and determine what features are supported
 * (all asics).
 * returns 0 on success, error on failure.
 */
static int radeon_atcs_verify_interface(acpi_handle handle,
                                        struct radeon_atcs *atcs)
{
        union acpi_object *info;
        struct atcs_verify_interface output;
        size_t size;
        int err = 0;

        info = radeon_atcs_call(handle, ATCS_FUNCTION_VERIFY_INTERFACE, NULL);
        if (!info)
                return -EIO;

        memset(&output, 0, sizeof(output));

        size = *(u16 *) info->buffer.pointer;
        if (size < 8) {
                DRM_INFO("ATCS buffer is too small: %zu\n", size);
                err = -EINVAL;
                goto out;
        }
        size = min(sizeof(output), size);

        memcpy(&output, info->buffer.pointer, size);

        /* TODO: check version? */
        DRM_DEBUG_DRIVER("ATCS version %u\n", output.version);

        radeon_atcs_parse_functions(&atcs->functions, output.function_bits);

out:
        kfree(info);
        return err;
}

/**
 * radeon_acpi_is_pcie_performance_request_supported
 *
 * @rdev: radeon_device pointer
 *
 * Check if the ATCS pcie_perf_req and pcie_dev_rdy methods
 * are supported (all asics).
 * returns true if supported, false if not.
 */
bool radeon_acpi_is_pcie_performance_request_supported(struct radeon_device *rdev)
{
        struct radeon_atcs *atcs = &rdev->atcs;

        if (atcs->functions.pcie_perf_req && atcs->functions.pcie_dev_rdy)
                return true;

        return false;
}

/**
 * radeon_acpi_pcie_notify_device_ready
 *
 * @rdev: radeon_device pointer
 *
 * Executes the PCIE_DEVICE_READY_NOTIFICATION method
 * (all asics).
 * returns 0 on success, error on failure.
 */
int radeon_acpi_pcie_notify_device_ready(struct radeon_device *rdev)
{
        acpi_handle handle;
        union acpi_object *info;
        struct radeon_atcs *atcs = &rdev->atcs;

        /* Get the device handle */
        handle = ACPI_HANDLE(&rdev->pdev->dev);
        if (!handle)
                return -EINVAL;

        if (!atcs->functions.pcie_dev_rdy)
                return -EINVAL;

        info = radeon_atcs_call(handle, ATCS_FUNCTION_PCIE_DEVICE_READY_NOTIFICATION, NULL);
        if (!info)
                return -EIO;

        kfree(info);

        return 0;
}

/**
 * radeon_acpi_pcie_performance_request
 *
 * @rdev: radeon_device pointer
 * @perf_req: requested perf level (pcie gen speed)
 * @advertise: set advertise caps flag if set
 *
 * Executes the PCIE_PERFORMANCE_REQUEST method to
 * change the pcie gen speed (all asics).
 * returns 0 on success, error on failure.
 */
int radeon_acpi_pcie_performance_request(struct radeon_device *rdev,
                                         u8 perf_req, bool advertise)
{
        acpi_handle handle;
        union acpi_object *info;
        struct radeon_atcs *atcs = &rdev->atcs;
        struct atcs_pref_req_input atcs_input;
        struct atcs_pref_req_output atcs_output;
        struct acpi_buffer params;
        size_t size;
        u32 retry = 3;

        /* Get the device handle */
        handle = ACPI_HANDLE(&rdev->pdev->dev);
        if (!handle)
                return -EINVAL;

        if (!atcs->functions.pcie_perf_req)
                return -EINVAL;

        atcs_input.size = sizeof(struct atcs_pref_req_input);
        /* client id (bit 2-0: func num, 7-3: dev num, 15-8: bus num) */
        atcs_input.client_id = rdev->pdev->devfn | (rdev->pdev->bus->number << 8);
        atcs_input.valid_flags_mask = ATCS_VALID_FLAGS_MASK;
        atcs_input.flags = ATCS_WAIT_FOR_COMPLETION;
        if (advertise)
                atcs_input.flags |= ATCS_ADVERTISE_CAPS;
        atcs_input.req_type = ATCS_PCIE_LINK_SPEED;
        atcs_input.perf_req = perf_req;

        params.length = sizeof(struct atcs_pref_req_input);
        params.pointer = &atcs_input;

        while (retry--) {
                info = radeon_atcs_call(handle, ATCS_FUNCTION_PCIE_PERFORMANCE_REQUEST, &params);
                if (!info)
                        return -EIO;

                memset(&atcs_output, 0, sizeof(atcs_output));

                size = *(u16 *) info->buffer.pointer;
                if (size < 3) {
                        DRM_INFO("ATCS buffer is too small: %zu\n", size);
                        kfree(info);
                        return -EINVAL;
                }
                size = min(sizeof(atcs_output), size);

                memcpy(&atcs_output, info->buffer.pointer, size);

                kfree(info);

                switch (atcs_output.ret_val) {
                case ATCS_REQUEST_REFUSED:
                default:
                        return -EINVAL;
                case ATCS_REQUEST_COMPLETE:
                        return 0;
                case ATCS_REQUEST_IN_PROGRESS:
                        udelay(10);
                        break;
                }
        }

        return 0;
}

/**
 * radeon_acpi_event - handle notify events
 *
 * @nb: notifier block
 * @val: val
 * @data: acpi event
 *
 * Calls relevant radeon functions in response to various
 * acpi events.
 * Returns NOTIFY code
 */
static int radeon_acpi_event(struct notifier_block *nb,
                             unsigned long val,
                             void *data)
{
        struct radeon_device *rdev = container_of(nb, struct radeon_device, acpi_nb);
        struct acpi_bus_event *entry = (struct acpi_bus_event *)data;

        if (strcmp(entry->device_class, ACPI_AC_CLASS) == 0) {
                if (power_supply_is_system_supplied() > 0)
                        DRM_DEBUG_DRIVER("pm: AC\n");
                else
                        DRM_DEBUG_DRIVER("pm: DC\n");

                radeon_pm_acpi_event_handler(rdev);
        }

        /* Check for pending SBIOS requests */
        return radeon_atif_handler(rdev, entry);
}

/* Call all ACPI methods here */
/**
 * radeon_acpi_init - init driver acpi support
 *
 * @rdev: radeon_device pointer
 *
 * Verifies the AMD ACPI interfaces and registers with the acpi
 * notifier chain (all asics).
 * Returns 0 on success, error on failure.
 */
int radeon_acpi_init(struct radeon_device *rdev)
{
        acpi_handle handle;
        struct radeon_atif *atif = &rdev->atif;
        struct radeon_atcs *atcs = &rdev->atcs;
        int ret;

        /* Get the device handle */
        handle = ACPI_HANDLE(&rdev->pdev->dev);

        /* No need to proceed if we're sure that ATIF is not supported */
        if (!ASIC_IS_AVIVO(rdev) || !rdev->bios || !handle)
                return 0;

        /* Call the ATCS method */
        ret = radeon_atcs_verify_interface(handle, atcs);
        if (ret) {
                DRM_DEBUG_DRIVER("Call to ATCS verify_interface failed: %d\n", ret);
        }

        /* Call the ATIF method */
        ret = radeon_atif_verify_interface(handle, atif);
        if (ret) {
                DRM_DEBUG_DRIVER("Call to ATIF verify_interface failed: %d\n", ret);
                goto out;
        }

        if (atif->notifications.brightness_change) {
                struct drm_encoder *tmp;
                struct radeon_encoder *target = NULL;

                /* Find the encoder controlling the brightness */
                list_for_each_entry(tmp, &rdev->ddev->mode_config.encoder_list,
                                head) {
                        struct radeon_encoder *enc = to_radeon_encoder(tmp);

                        if ((enc->devices & (ATOM_DEVICE_LCD_SUPPORT)) &&
                            enc->enc_priv) {
                                if (rdev->is_atom_bios) {
                                        struct radeon_encoder_atom_dig *dig = enc->enc_priv;
                                        if (dig->bl_dev) {
                                                target = enc;
                                                break;
                                        }
                                } else {
                                        struct radeon_encoder_lvds *dig = enc->enc_priv;
                                        if (dig->bl_dev) {
                                                target = enc;
                                                break;
                                        }
                                }
                        }
                }

                atif->encoder_for_bl = target;
                if (!target) {
                        /* Brightness change notification is enabled, but we
                         * didn't find a backlight controller, this should
                         * never happen.
                         */
                        DRM_ERROR("Cannot find a backlight controller\n");
                }
        }

        if (atif->functions.sbios_requests && !atif->functions.system_params) {
                /* XXX check this workraround, if sbios request function is
                 * present we have to see how it's configured in the system
                 * params
                 */
                atif->functions.system_params = true;
        }

        if (atif->functions.system_params) {
                ret = radeon_atif_get_notification_params(handle,
                                &atif->notification_cfg);
                if (ret) {
                        DRM_DEBUG_DRIVER("Call to GET_SYSTEM_PARAMS failed: %d\n",
                                        ret);
                        /* Disable notification */
                        atif->notification_cfg.enabled = false;
                }
        }

out:
        rdev->acpi_nb.notifier_call = radeon_acpi_event;
        register_acpi_notifier(&rdev->acpi_nb);

        return ret;
}

/**
 * radeon_acpi_fini - tear down driver acpi support
 *
 * @rdev: radeon_device pointer
 *
 * Unregisters with the acpi notifier chain (all asics).
 */
void radeon_acpi_fini(struct radeon_device *rdev)
{
        unregister_acpi_notifier(&rdev->acpi_nb);
}