text: /*
   * 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/drmP.h>
  #include <drm/drm_crtc_helper.h>
  #include "amdgpu.h"
  #include "amdgpu_pm.h"
  #include "amd_acpi.h"
  #include "atom.h"
  
  struct amdgpu_atif_notification_cfg {
  	bool enabled;
  	int command_code;
  };
  
  struct amdgpu_atif_notifications {
  	bool display_switch;
  	bool expansion_mode_change;
  	bool thermal_state;
  	bool forced_power_state;
  	bool system_power_state;
  	bool display_conf_change;
  	bool px_gfx_switch;
  	bool brightness_change;
  	bool dgpu_display_event;
  };
  
  struct amdgpu_atif_functions {
  	bool system_params;
  	bool sbios_requests;
  	bool select_active_disp;
  	bool lid_state;
  	bool get_tv_standard;
  	bool set_tv_standard;
  	bool get_panel_expansion_mode;
  	bool set_panel_expansion_mode;
  	bool temperature_change;
  	bool graphics_device_types;
  };
  
  struct amdgpu_atif {
  	acpi_handle handle;
  
  	struct amdgpu_atif_notifications notifications;
  	struct amdgpu_atif_functions functions;
  	struct amdgpu_atif_notification_cfg notification_cfg;
  	struct amdgpu_encoder *encoder_for_bl;
  };
  
  /* 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->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;
  }
  
  /**
   * 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->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;
  }
  
  /**
   * 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_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 code
   */
  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;
  
  	if (!atif ||
  	    !atif->notification_cfg.enabled ||
  	    event->type != atif->notification_cfg.command_code)
  		/* Not our event */
  		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_DONE;
  
  		DRM_DEBUG_DRIVER("ATIF: %d pending SBIOS requests\n", count);
  
  		/* todo: add DC handling */
  		if ((req.pending & ATIF_PANEL_BRIGHTNESS_CHANGE_REQUEST) &&
  		    !amdgpu_device_has_dc_support(adev)) {
  			struct amdgpu_encoder *enc = atif->encoder_for_bl;
  
  			if (enc) {
  				struct amdgpu_encoder_atom_dig *dig = enc->enc_priv;
  
  				DRM_DEBUG_DRIVER("Changing brightness to %d\n",
  						 req.backlight_level);
  
  				amdgpu_display_backlight_set_level(adev, enc, req.backlight_level);
  
  #if defined(CONFIG_BACKLIGHT_CLASS_DEVICE) || defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE)
  				backlight_force_update(dig->bl_dev,
  						       BACKLIGHT_UPDATE_HOTKEY);
  #endif
  			}
  		}
  		if (req.pending & ATIF_DGPU_DISPLAY_EVENT) {
  			if ((adev->flags & AMD_IS_PX) &&
  			    amdgpu_atpx_dgpu_req_power_for_displays()) {
  				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) {
  		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->encoder_for_bl = enc;
  					break;
  				}
  			}
  		}
  	}
  
  	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;
  		}
  	}
  
  out:
  	adev->acpi_nb.notifier_call = amdgpu_acpi_event;
  	register_acpi_notifier(&adev->acpi_nb);
  
  	return ret;
  }
  
  /**
   * 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);
  	if (adev->atif)
  		kfree(adev->atif);
  }
  