/*
 * 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/pm_runtime.h>
#include <acpi/video.h>

#include <drm/drm_crtc_helper.h>
#include "amdgpu.h"
#include "amdgpu_pm.h"
#include "amdgpu_display.h"
#include "amd_acpi.h"
#include "atom.h"

struct amdgpu_atif_notification_cfg {
        bool enabled;
        int command_code;
};

struct amdgpu_atif_notifications {
        bool thermal_state;
        bool forced_power_state;
        bool system_power_state;
        bool brightness_change;
        bool dgpu_display_event;
        bool gpu_package_power_limit;
};

struct amdgpu_atif_functions {
        bool system_params;
        bool sbios_requests;
        bool temperature_change;
        bool query_backlight_transfer_characteristics;
        bool ready_to_undock;
        bool external_gpu_information;
};

struct amdgpu_atif {
        acpi_handle handle;

        struct amdgpu_atif_notifications notifications;
        struct amdgpu_atif_functions functions;
        struct amdgpu_atif_notification_cfg notification_cfg;
#if defined(CONFIG_BACKLIGHT_CLASS_DEVICE) || defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE)
        struct backlight_device *bd;
#endif
        struct amdgpu_dm_backlight_caps backlight_caps;
};

/* Call the ATIF method
 */
/**
 * amdgpu_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 *amdgpu_atif_call(struct amdgpu_atif *atif,
                                           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(atif->handle, NULL, &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;
}

/**
 * amdgpu_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 amdgpu_atif_parse_notification(struct amdgpu_atif_notifications *n, u32 mask)
{
        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->brightness_change = mask & ATIF_PANEL_BRIGHTNESS_CHANGE_REQUEST_SUPPORTED;
        n->dgpu_display_event = mask & ATIF_DGPU_DISPLAY_EVENT_SUPPORTED;
        n->gpu_package_power_limit = mask & ATIF_GPU_PACKAGE_POWER_LIMIT_REQUEST_SUPPORTED;
}

/**
 * amdgpu_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 amdgpu_atif_parse_functions(struct amdgpu_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->temperature_change = mask & ATIF_TEMPERATURE_CHANGE_NOTIFICATION_SUPPORTED;
        f->query_backlight_transfer_characteristics =
                mask & ATIF_QUERY_BACKLIGHT_TRANSFER_CHARACTERISTICS_SUPPORTED;
        f->ready_to_undock = mask & ATIF_READY_TO_UNDOCK_NOTIFICATION_SUPPORTED;
        f->external_gpu_information = mask & ATIF_GET_EXTERNAL_GPU_INFORMATION_SUPPORTED;
}

/**
 * amdgpu_atif_verify_interface - verify ATIF
 *
 * @handle: acpi handle
 * @atif: amdgpu 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 amdgpu_atif_verify_interface(struct amdgpu_atif *atif)
{
        union acpi_object *info;
        struct atif_verify_interface output;
        size_t size;
        int err = 0;

        info = amdgpu_atif_call(atif, 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);

        amdgpu_atif_parse_notification(&atif->notifications, output.notification_mask);
        amdgpu_atif_parse_functions(&atif->functions, output.function_bits);

out:
        kfree(info);
        return err;
}

static acpi_handle amdgpu_atif_probe_handle(acpi_handle dhandle)
{
        acpi_handle handle = NULL;
        char acpi_method_name[255] = { 0 };
        struct acpi_buffer buffer = { sizeof(acpi_method_name), acpi_method_name };
        acpi_status status;

        /* For PX/HG systems, ATIF and ATPX are in the iGPU's namespace, on dGPU only
         * systems, ATIF is in the dGPU's namespace.
         */
        status = acpi_get_handle(dhandle, "ATIF", &handle);
        if (ACPI_SUCCESS(status))
                goto out;

        if (amdgpu_has_atpx()) {
                status = acpi_get_handle(amdgpu_atpx_get_dhandle(), "ATIF",
                                         &handle);
                if (ACPI_SUCCESS(status))
                        goto out;
        }

        DRM_DEBUG_DRIVER("No ATIF handle found\n");
        return NULL;
out:
        acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
        DRM_DEBUG_DRIVER("Found ATIF handle %s\n", acpi_method_name);
        return handle;
}

/**
 * amdgpu_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 amdgpu_atif_get_notification_params(struct amdgpu_atif *atif)
{
        union acpi_object *info;
        struct amdgpu_atif_notification_cfg *n = &atif->notification_cfg;
        struct atif_system_params params;
        size_t size;
        int err = 0;

        info = amdgpu_atif_call(atif, 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;
}

/**
 * amdgpu_atif_query_backlight_caps - get min and max backlight input signal
 *
 * @handle: acpi handle
 *
 * Execute the QUERY_BRIGHTNESS_TRANSFER_CHARACTERISTICS ATIF function
 * to determine the acceptable range of backlight values
 *
 * Backlight_caps.caps_valid will be set to true if the query is successful
 *
 * The input signals are in range 0-255
 *
 * This function assumes the display with backlight is the first LCD
 *
 * Returns 0 on success, error on failure.
 */
static int amdgpu_atif_query_backlight_caps(struct amdgpu_atif *atif)
{
        union acpi_object *info;
        struct atif_qbtc_output characteristics;
        struct atif_qbtc_arguments arguments;
        struct acpi_buffer params;
        size_t size;
        int err = 0;

        arguments.size = sizeof(arguments);
        arguments.requested_display = ATIF_QBTC_REQUEST_LCD1;

        params.length = sizeof(arguments);
        params.pointer = (void *)&arguments;

        info = amdgpu_atif_call(atif,
                ATIF_FUNCTION_QUERY_BRIGHTNESS_TRANSFER_CHARACTERISTICS,
                &params);
        if (!info) {
                err = -EIO;
                goto out;
        }

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

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

        atif->backlight_caps.caps_valid = true;
        atif->backlight_caps.min_input_signal =
                        characteristics.min_input_signal;
        atif->backlight_caps.max_input_signal =
                        characteristics.max_input_signal;
out:
        kfree(info);
        return err;
}

/**
 * amdgpu_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 amdgpu_atif_get_sbios_requests(struct amdgpu_atif *atif,
                                          struct atif_sbios_requests *req)
{
        union acpi_object *info;
        size_t size;
        int count = 0;

        info = amdgpu_atif_call(atif, 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;
}

/**
 * amdgpu_atif_handler - handle ATIF notify requests
 *
 * @adev: amdgpu_device pointer
 * @event: atif sbios request struct
 *
 * Checks the acpi event and if it matches an atif event,
 * handles it.
 *
 * Returns:
 * NOTIFY_BAD or NOTIFY_DONE, depending on the event.
 */
static int amdgpu_atif_handler(struct amdgpu_device *adev,
                               struct acpi_bus_event *event)
{
        struct amdgpu_atif *atif = adev->atif;
        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;

        /* Is this actually our event? */
        if (!atif ||
            !atif->notification_cfg.enabled ||
            event->type != atif->notification_cfg.command_code) {
                /* These events will generate keypresses otherwise */
                if (event->type == ACPI_VIDEO_NOTIFY_PROBE)
                        return NOTIFY_BAD;
                else
                        return NOTIFY_DONE;
        }

        if (atif->functions.sbios_requests) {
                struct atif_sbios_requests req;

                /* Check pending SBIOS requests */
                count = amdgpu_atif_get_sbios_requests(atif, &req);

                if (count <= 0)
                        return NOTIFY_BAD;

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

                if (req.pending & ATIF_PANEL_BRIGHTNESS_CHANGE_REQUEST) {
#if defined(CONFIG_BACKLIGHT_CLASS_DEVICE) || defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE)
                        if (atif->bd) {
                                DRM_DEBUG_DRIVER("Changing brightness to %d\n",
                                                 req.backlight_level);
                                /*
                                 * XXX backlight_device_set_brightness() is
                                 * hardwired to post BACKLIGHT_UPDATE_SYSFS.
                                 * It probably should accept 'reason' parameter.
                                 */
                                backlight_device_set_brightness(atif->bd, req.backlight_level);
                        }
#endif
                }

                if (req.pending & ATIF_DGPU_DISPLAY_EVENT) {
                        if (adev->flags & AMD_IS_PX) {
                                pm_runtime_get_sync(adev->ddev->dev);
                                /* Just fire off a uevent and let userspace tell us what to do */
                                drm_helper_hpd_irq_event(adev->ddev);
                                pm_runtime_mark_last_busy(adev->ddev->dev);
                                pm_runtime_put_autosuspend(adev->ddev->dev);
                        }
                }
                /* 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
 */
/**
 * amdgpu_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 *amdgpu_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;
}

/**
 * amdgpu_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 amdgpu_atcs_parse_functions(struct amdgpu_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;
}

/**
 * amdgpu_atcs_verify_interface - verify ATCS
 *
 * @handle: acpi handle
 * @atcs: amdgpu 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 amdgpu_atcs_verify_interface(acpi_handle handle,
                                        struct amdgpu_atcs *atcs)
{
        union acpi_object *info;
        struct atcs_verify_interface output;
        size_t size;
        int err = 0;

        info = amdgpu_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);

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

out:
        kfree(info);
        return err;
}

/**
 * amdgpu_acpi_is_pcie_performance_request_supported
 *
 * @adev: amdgpu_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 amdgpu_acpi_is_pcie_performance_request_supported(struct amdgpu_device *adev)
{
        struct amdgpu_atcs *atcs = &adev->atcs;

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

        return false;
}

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

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

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

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

        kfree(info);

        return 0;
}

/**
 * amdgpu_acpi_pcie_performance_request
 *
 * @adev: amdgpu_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 amdgpu_acpi_pcie_performance_request(struct amdgpu_device *adev,
                                         u8 perf_req, bool advertise)
{
        acpi_handle handle;
        union acpi_object *info;
        struct amdgpu_atcs *atcs = &adev->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;

        if (amdgpu_acpi_pcie_notify_device_ready(adev))
                return -EINVAL;

        /* Get the device handle */
        handle = ACPI_HANDLE(&adev->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 = adev->pdev->devfn | (adev->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 = amdgpu_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;
}

/**
 * amdgpu_acpi_event - handle notify events
 *
 * @nb: notifier block
 * @val: val
 * @data: acpi event
 *
 * Calls relevant amdgpu functions in response to various
 * acpi events.
 * Returns NOTIFY code
 */
static int amdgpu_acpi_event(struct notifier_block *nb,
                             unsigned long val,
                             void *data)
{
        struct amdgpu_device *adev = container_of(nb, struct amdgpu_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");

                amdgpu_pm_acpi_event_handler(adev);
        }

        /* Check for pending SBIOS requests */
        return amdgpu_atif_handler(adev, entry);
}

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

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

        if (!adev->bios || !handle)
                return 0;

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

        /* Probe for ATIF, and initialize it if found */
        atif_handle = amdgpu_atif_probe_handle(handle);
        if (!atif_handle)
                goto out;

        atif = kzalloc(sizeof(*atif), GFP_KERNEL);
        if (!atif) {
                DRM_WARN("Not enough memory to initialize ATIF\n");
                goto out;
        }
        atif->handle = atif_handle;

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

        if (atif->notifications.brightness_change) {
#if defined(CONFIG_BACKLIGHT_CLASS_DEVICE) || defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE)
                if (amdgpu_device_has_dc_support(adev)) {
#if defined(CONFIG_DRM_AMD_DC)
                        struct amdgpu_display_manager *dm = &adev->dm;
                        atif->bd = dm->backlight_dev;
#endif
                } else {
                        struct drm_encoder *tmp;

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

                                if ((enc->devices & (ATOM_DEVICE_LCD_SUPPORT)) &&
                                    enc->enc_priv) {
                                        struct amdgpu_encoder_atom_dig *dig = enc->enc_priv;
                                        if (dig->bl_dev) {
                                                atif->bd = dig->bl_dev;
                                                break;
                                        }
                                }
                        }
                }
        }
#endif

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

        if (atif->functions.query_backlight_transfer_characteristics) {
                ret = amdgpu_atif_query_backlight_caps(atif);
                if (ret) {
                        DRM_DEBUG_DRIVER("Call to QUERY_BACKLIGHT_TRANSFER_CHARACTERISTICS failed: %d\n",
                                        ret);
                        atif->backlight_caps.caps_valid = false;
                }
        } else {
                atif->backlight_caps.caps_valid = false;
        }

out:
        adev->acpi_nb.notifier_call = amdgpu_acpi_event;
        register_acpi_notifier(&adev->acpi_nb);

        return ret;
}

void amdgpu_acpi_get_backlight_caps(struct amdgpu_device *adev,
                struct amdgpu_dm_backlight_caps *caps)
{
        if (!adev->atif) {
                caps->caps_valid = false;
                return;
        }
        caps->caps_valid = adev->atif->backlight_caps.caps_valid;
        caps->min_input_signal = adev->atif->backlight_caps.min_input_signal;
        caps->max_input_signal = adev->atif->backlight_caps.max_input_signal;
}

/**
 * amdgpu_acpi_fini - tear down driver acpi support
 *
 * @adev: amdgpu_device pointer
 *
 * Unregisters with the acpi notifier chain (all asics).
 */
void amdgpu_acpi_fini(struct amdgpu_device *adev)
{
        unregister_acpi_notifier(&adev->acpi_nb);
        kfree(adev->atif);
}