drivers/gpu/drm/drm_crtc.c

/*
 * Copyright (c) 2006-2008 Intel Corporation
 * Copyright (c) 2007 Dave Airlie <airlied@linux.ie>
 * Copyright (c) 2008 Red Hat Inc.
 *
 * DRM core CRTC related functions
 *
 * Permission to use, copy, modify, distribute, and sell this software and its
 * documentation for any purpose is hereby granted without fee, provided that
 * the above copyright notice appear in all copies and that both that copyright
 * notice and this permission notice appear in supporting documentation, and
 * that the name of the copyright holders not be used in advertising or
 * publicity pertaining to distribution of the software without specific,
 * written prior permission.  The copyright holders make no representations
 * about the suitability of this software for any purpose.  It is provided "as
 * is" without express or implied warranty.
 *
 * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
 * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
 * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
 * OF THIS SOFTWARE.
 *
 * Authors:
 *      Keith Packard
 *	Eric Anholt <eric@anholt.net>
 *      Dave Airlie <airlied@linux.ie>
 *      Jesse Barnes <jesse.barnes@intel.com>
 */
#include <linux/ctype.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/export.h>
#include <linux/fence.h>
#include <drm/drmP.h>
#include <drm/drm_crtc.h>
#include <drm/drm_edid.h>
#include <drm/drm_fourcc.h>
#include <drm/drm_modeset_lock.h>
#include <drm/drm_atomic.h>
#include <drm/drm_auth.h>
#include <drm/drm_framebuffer.h>

#include "drm_crtc_internal.h"
#include "drm_internal.h"

/**
 * drm_crtc_from_index - find the registered CRTC at an index
 * @dev: DRM device
 * @idx: index of registered CRTC to find for
 *
 * Given a CRTC index, return the registered CRTC from DRM device's
 * list of CRTCs with matching index. This is the inverse of drm_crtc_index().
 * It's useful in the vblank callbacks (like &drm_driver.enable_vblank or
 * &drm_driver.disable_vblank), since that still deals with indices instead
 * of pointers to &struct drm_crtc."
 */
struct drm_crtc *drm_crtc_from_index(struct drm_device *dev, int idx)
{
        struct drm_crtc *crtc;

        drm_for_each_crtc(crtc, dev)
                if (idx == crtc->index)
                        return crtc;

        return NULL;
}
EXPORT_SYMBOL(drm_crtc_from_index);

/**
 * drm_crtc_force_disable - Forcibly turn off a CRTC
 * @crtc: CRTC to turn off
 *
 * Returns:
 * Zero on success, error code on failure.
 */
int drm_crtc_force_disable(struct drm_crtc *crtc)
{
	struct drm_mode_set set = {
		.crtc = crtc,
	};

	return drm_mode_set_config_internal(&set);
}
EXPORT_SYMBOL(drm_crtc_force_disable);

/**
 * drm_crtc_force_disable_all - Forcibly turn off all enabled CRTCs
 * @dev: DRM device whose CRTCs to turn off
 *
 * Drivers may want to call this on unload to ensure that all displays are
 * unlit and the GPU is in a consistent, low power state. Takes modeset locks.
 *
 * Returns:
 * Zero on success, error code on failure.
 */
int drm_crtc_force_disable_all(struct drm_device *dev)
{
	struct drm_crtc *crtc;
	int ret = 0;

	drm_modeset_lock_all(dev);
	drm_for_each_crtc(crtc, dev)
		if (crtc->enabled) {
			ret = drm_crtc_force_disable(crtc);
			if (ret)
				goto out;
		}
out:
	drm_modeset_unlock_all(dev);
	return ret;
}
EXPORT_SYMBOL(drm_crtc_force_disable_all);

DEFINE_WW_CLASS(crtc_ww_class);

static unsigned int drm_num_crtcs(struct drm_device *dev)
{
	unsigned int num = 0;
	struct drm_crtc *tmp;

	drm_for_each_crtc(tmp, dev) {
		num++;
	}

	return num;
}

int drm_crtc_register_all(struct drm_device *dev)
{
	struct drm_crtc *crtc;
	int ret = 0;

	drm_for_each_crtc(crtc, dev) {
		if (crtc->funcs->late_register)
			ret = crtc->funcs->late_register(crtc);
		if (ret)
			return ret;
	}

	return 0;
}

void drm_crtc_unregister_all(struct drm_device *dev)
{
	struct drm_crtc *crtc;

	drm_for_each_crtc(crtc, dev) {
		if (crtc->funcs->early_unregister)
			crtc->funcs->early_unregister(crtc);
	}
}

static const struct fence_ops drm_crtc_fence_ops;

static struct drm_crtc *fence_to_crtc(struct fence *fence)
{
	BUG_ON(fence->ops != &drm_crtc_fence_ops);
	return container_of(fence->lock, struct drm_crtc, fence_lock);
}

static const char *drm_crtc_fence_get_driver_name(struct fence *fence)
{
	struct drm_crtc *crtc = fence_to_crtc(fence);

	return crtc->dev->driver->name;
}

static const char *drm_crtc_fence_get_timeline_name(struct fence *fence)
{
	struct drm_crtc *crtc = fence_to_crtc(fence);

	return crtc->timeline_name;
}

static bool drm_crtc_fence_enable_signaling(struct fence *fence)
{
	return true;
}

static const struct fence_ops drm_crtc_fence_ops = {
	.get_driver_name = drm_crtc_fence_get_driver_name,
	.get_timeline_name = drm_crtc_fence_get_timeline_name,
	.enable_signaling = drm_crtc_fence_enable_signaling,
	.wait = fence_default_wait,
};

struct fence *drm_crtc_create_fence(struct drm_crtc *crtc)
{
	struct fence *fence;

	fence = kzalloc(sizeof(*fence), GFP_KERNEL);
	if (!fence)
		return NULL;

	fence_init(fence, &drm_crtc_fence_ops, &crtc->fence_lock,
		       crtc->fence_context, ++crtc->fence_seqno);

	return fence;
}

/**
 * drm_crtc_init_with_planes - Initialise a new CRTC object with
 *    specified primary and cursor planes.
 * @dev: DRM device
 * @crtc: CRTC object to init
 * @primary: Primary plane for CRTC
 * @cursor: Cursor plane for CRTC
 * @funcs: callbacks for the new CRTC
 * @name: printf style format string for the CRTC name, or NULL for default name
 *
 * Inits a new object created as base part of a driver crtc object. Drivers
 * should use this function instead of drm_crtc_init(), which is only provided
 * for backwards compatibility with drivers which do not yet support universal
 * planes). For really simple hardware which has only 1 plane look at
 * drm_simple_display_pipe_init() instead.
 *
 * Returns:
 * Zero on success, error code on failure.
 */
int drm_crtc_init_with_planes(struct drm_device *dev, struct drm_crtc *crtc,
			      struct drm_plane *primary,
			      struct drm_plane *cursor,
			      const struct drm_crtc_funcs *funcs,
			      const char *name, ...)
{
	struct drm_mode_config *config = &dev->mode_config;
	int ret;

	WARN_ON(primary && primary->type != DRM_PLANE_TYPE_PRIMARY);
	WARN_ON(cursor && cursor->type != DRM_PLANE_TYPE_CURSOR);

	crtc->dev = dev;
	crtc->funcs = funcs;

	INIT_LIST_HEAD(&crtc->commit_list);
	spin_lock_init(&crtc->commit_lock);

	drm_modeset_lock_init(&crtc->mutex);
	ret = drm_mode_object_get(dev, &crtc->base, DRM_MODE_OBJECT_CRTC);
	if (ret)
		return ret;

	if (name) {
		va_list ap;

		va_start(ap, name);
		crtc->name = kvasprintf(GFP_KERNEL, name, ap);
		va_end(ap);
	} else {
		crtc->name = kasprintf(GFP_KERNEL, "crtc-%d",
				       drm_num_crtcs(dev));
	}
	if (!crtc->name) {
		drm_mode_object_unregister(dev, &crtc->base);
		return -ENOMEM;
	}

	crtc->fence_context = fence_context_alloc(1);
	spin_lock_init(&crtc->fence_lock);
	snprintf(crtc->timeline_name, sizeof(crtc->timeline_name),
		 "CRTC:%d-%s", crtc->base.id, crtc->name);

	crtc->base.properties = &crtc->properties;

	list_add_tail(&crtc->head, &config->crtc_list);
	crtc->index = config->num_crtc++;

	crtc->primary = primary;
	crtc->cursor = cursor;
	if (primary)
		primary->possible_crtcs = 1 << drm_crtc_index(crtc);
	if (cursor)
		cursor->possible_crtcs = 1 << drm_crtc_index(crtc);

	if (drm_core_check_feature(dev, DRIVER_ATOMIC)) {
		drm_object_attach_property(&crtc->base, config->prop_active, 0);
		drm_object_attach_property(&crtc->base, config->prop_mode_id, 0);
		drm_object_attach_property(&crtc->base,
					   config->prop_out_fence_ptr, 0);
	}

	return 0;
}
EXPORT_SYMBOL(drm_crtc_init_with_planes);

/**
 * drm_crtc_cleanup - Clean up the core crtc usage
 * @crtc: CRTC to cleanup
 *
 * This function cleans up @crtc and removes it from the DRM mode setting
 * core. Note that the function does *not* free the crtc structure itself,
 * this is the responsibility of the caller.
 */
void drm_crtc_cleanup(struct drm_crtc *crtc)
{
	struct drm_device *dev = crtc->dev;

	/* Note that the crtc_list is considered to be static; should we
	 * remove the drm_crtc at runtime we would have to decrement all
	 * the indices on the drm_crtc after us in the crtc_list.
	 */

	kfree(crtc->gamma_store);
	crtc->gamma_store = NULL;

	drm_modeset_lock_fini(&crtc->mutex);

	drm_mode_object_unregister(dev, &crtc->base);
	list_del(&crtc->head);
	dev->mode_config.num_crtc--;

	WARN_ON(crtc->state && !crtc->funcs->atomic_destroy_state);
	if (crtc->state && crtc->funcs->atomic_destroy_state)
		crtc->funcs->atomic_destroy_state(crtc, crtc->state);

	kfree(crtc->name);

	memset(crtc, 0, sizeof(*crtc));
}
EXPORT_SYMBOL(drm_crtc_cleanup);

/**
 * drm_mode_getcrtc - get CRTC configuration
 * @dev: drm device for the ioctl
 * @data: data pointer for the ioctl
 * @file_priv: drm file for the ioctl call
 *
 * Construct a CRTC configuration structure to return to the user.
 *
 * Called by the user via ioctl.
 *
 * Returns:
 * Zero on success, negative errno on failure.
 */
int drm_mode_getcrtc(struct drm_device *dev,
		     void *data, struct drm_file *file_priv)
{
	struct drm_mode_crtc *crtc_resp = data;
	struct drm_crtc *crtc;

	if (!drm_core_check_feature(dev, DRIVER_MODESET))
		return -EINVAL;

	crtc = drm_crtc_find(dev, crtc_resp->crtc_id);
	if (!crtc)
		return -ENOENT;

	drm_modeset_lock_crtc(crtc, crtc->primary);
	crtc_resp->gamma_size = crtc->gamma_size;
	if (crtc->primary->fb)
		crtc_resp->fb_id = crtc->primary->fb->base.id;
	else
		crtc_resp->fb_id = 0;

	if (crtc->state) {
		crtc_resp->x = crtc->primary->state->src_x >> 16;
		crtc_resp->y = crtc->primary->state->src_y >> 16;
		if (crtc->state->enable) {
			drm_mode_convert_to_umode(&crtc_resp->mode, &crtc->state->mode);
			crtc_resp->mode_valid = 1;

		} else {
			crtc_resp->mode_valid = 0;
		}
	} else {
		crtc_resp->x = crtc->x;
		crtc_resp->y = crtc->y;
		if (crtc->enabled) {
			drm_mode_convert_to_umode(&crtc_resp->mode, &crtc->mode);
			crtc_resp->mode_valid = 1;

		} else {
			crtc_resp->mode_valid = 0;
		}
	}
	drm_modeset_unlock_crtc(crtc);

	return 0;
}

/**
 * drm_mode_set_config_internal - helper to call ->set_config
 * @set: modeset config to set
 *
 * This is a little helper to wrap internal calls to the ->set_config driver
 * interface. The only thing it adds is correct refcounting dance.
 *
 * Returns:
 * Zero on success, negative errno on failure.
 */
int drm_mode_set_config_internal(struct drm_mode_set *set)
{
	struct drm_crtc *crtc = set->crtc;
	struct drm_framebuffer *fb;
	struct drm_crtc *tmp;
	int ret;

	/*
	 * NOTE: ->set_config can also disable other crtcs (if we steal all
	 * connectors from it), hence we need to refcount the fbs across all
	 * crtcs. Atomic modeset will have saner semantics ...
	 */
	drm_for_each_crtc(tmp, crtc->dev)
		tmp->primary->old_fb = tmp->primary->fb;

	fb = set->fb;

	ret = crtc->funcs->set_config(set);
	if (ret == 0) {
		crtc->primary->crtc = crtc;
		crtc->primary->fb = fb;
	}

	drm_for_each_crtc(tmp, crtc->dev) {
		if (tmp->primary->fb)
			drm_framebuffer_reference(tmp->primary->fb);
		if (tmp->primary->old_fb)
			drm_framebuffer_unreference(tmp->primary->old_fb);
		tmp->primary->old_fb = NULL;
	}

	return ret;
}
EXPORT_SYMBOL(drm_mode_set_config_internal);

/**
 * drm_crtc_get_hv_timing - Fetches hdisplay/vdisplay for given mode
 * @mode: mode to query
 * @hdisplay: hdisplay value to fill in
 * @vdisplay: vdisplay value to fill in
 *
 * The vdisplay value will be doubled if the specified mode is a stereo mode of
 * the appropriate layout.
 */
void drm_crtc_get_hv_timing(const struct drm_display_mode *mode,
			    int *hdisplay, int *vdisplay)
{
	struct drm_display_mode adjusted;

	drm_mode_copy(&adjusted, mode);
	drm_mode_set_crtcinfo(&adjusted, CRTC_STEREO_DOUBLE_ONLY);
	*hdisplay = adjusted.crtc_hdisplay;
	*vdisplay = adjusted.crtc_vdisplay;
}
EXPORT_SYMBOL(drm_crtc_get_hv_timing);

/**
 * drm_crtc_check_viewport - Checks that a framebuffer is big enough for the
 *     CRTC viewport
 * @crtc: CRTC that framebuffer will be displayed on
 * @x: x panning
 * @y: y panning
 * @mode: mode that framebuffer will be displayed under
 * @fb: framebuffer to check size of
 */
int drm_crtc_check_viewport(const struct drm_crtc *crtc,
			    int x, int y,
			    const struct drm_display_mode *mode,
			    const struct drm_framebuffer *fb)

{
	int hdisplay, vdisplay;

	drm_crtc_get_hv_timing(mode, &hdisplay, &vdisplay);

	if (crtc->state &&
	    drm_rotation_90_or_270(crtc->primary->state->rotation))
		swap(hdisplay, vdisplay);

	return drm_framebuffer_check_src_coords(x << 16, y << 16,
						hdisplay << 16, vdisplay << 16,
						fb);
}
EXPORT_SYMBOL(drm_crtc_check_viewport);

/**
 * drm_mode_setcrtc - set CRTC configuration
 * @dev: drm device for the ioctl
 * @data: data pointer for the ioctl
 * @file_priv: drm file for the ioctl call
 *
 * Build a new CRTC configuration based on user request.
 *
 * Called by the user via ioctl.
 *
 * Returns:
 * Zero on success, negative errno on failure.
 */
int drm_mode_setcrtc(struct drm_device *dev, void *data,
		     struct drm_file *file_priv)
{
	struct drm_mode_config *config = &dev->mode_config;
	struct drm_mode_crtc *crtc_req = data;
	struct drm_crtc *crtc;
	struct drm_connector **connector_set = NULL, *connector;
	struct drm_framebuffer *fb = NULL;
	struct drm_display_mode *mode = NULL;
	struct drm_mode_set set;
	uint32_t __user *set_connectors_ptr;
	int ret;
	int i;

	if (!drm_core_check_feature(dev, DRIVER_MODESET))
		return -EINVAL;

	/*
	 * Universal plane src offsets are only 16.16, prevent havoc for
	 * drivers using universal plane code internally.
	 */
	if (crtc_req->x & 0xffff0000 || crtc_req->y & 0xffff0000)
		return -ERANGE;

	drm_modeset_lock_all(dev);
	crtc = drm_crtc_find(dev, crtc_req->crtc_id);
	if (!crtc) {
		DRM_DEBUG_KMS("Unknown CRTC ID %d\n", crtc_req->crtc_id);
		ret = -ENOENT;
		goto out;
	}
	DRM_DEBUG_KMS("[CRTC:%d:%s]\n", crtc->base.id, crtc->name);

	if (crtc_req->mode_valid) {
		/* If we have a mode we need a framebuffer. */
		/* If we pass -1, set the mode with the currently bound fb */
		if (crtc_req->fb_id == -1) {
			if (!crtc->primary->fb) {
				DRM_DEBUG_KMS("CRTC doesn't have current FB\n");
				ret = -EINVAL;
				goto out;
			}
			fb = crtc->primary->fb;
			/* Make refcounting symmetric with the lookup path. */
			drm_framebuffer_reference(fb);
		} else {
			fb = drm_framebuffer_lookup(dev, crtc_req->fb_id);
			if (!fb) {
				DRM_DEBUG_KMS("Unknown FB ID%d\n",
						crtc_req->fb_id);
				ret = -ENOENT;
				goto out;
			}
		}

		mode = drm_mode_create(dev);
		if (!mode) {
			ret = -ENOMEM;
			goto out;
		}

		ret = drm_mode_convert_umode(mode, &crtc_req->mode);
		if (ret) {
			DRM_DEBUG_KMS("Invalid mode\n");
			goto out;
		}

		/*
		 * Check whether the primary plane supports the fb pixel format.
		 * Drivers not implementing the universal planes API use a
		 * default formats list provided by the DRM core which doesn't
		 * match real hardware capabilities. Skip the check in that
		 * case.
		 */
		if (!crtc->primary->format_default) {
			ret = drm_plane_check_pixel_format(crtc->primary,
							   fb->pixel_format);
			if (ret) {
				char *format_name = drm_get_format_name(fb->pixel_format);
				DRM_DEBUG_KMS("Invalid pixel format %s\n", format_name);
				kfree(format_name);
				goto out;
			}
		}

		ret = drm_crtc_check_viewport(crtc, crtc_req->x, crtc_req->y,
					      mode, fb);
		if (ret)
			goto out;

	}

	if (crtc_req->count_connectors == 0 && mode) {
		DRM_DEBUG_KMS("Count connectors is 0 but mode set\n");
		ret = -EINVAL;
		goto out;
	}

	if (crtc_req->count_connectors > 0 && (!mode || !fb)) {
		DRM_DEBUG_KMS("Count connectors is %d but no mode or fb set\n",
			  crtc_req->count_connectors);
		ret = -EINVAL;
		goto out;
	}

	if (crtc_req->count_connectors > 0) {
		u32 out_id;

		/* Avoid unbounded kernel memory allocation */
		if (crtc_req->count_connectors > config->num_connector) {
			ret = -EINVAL;
			goto out;
		}

		connector_set = kmalloc_array(crtc_req->count_connectors,
					      sizeof(struct drm_connector *),
					      GFP_KERNEL);
		if (!connector_set) {
			ret = -ENOMEM;
			goto out;
		}

		for (i = 0; i < crtc_req->count_connectors; i++) {
			connector_set[i] = NULL;
			set_connectors_ptr = (uint32_t __user *)(unsigned long)crtc_req->set_connectors_ptr;
			if (get_user(out_id, &set_connectors_ptr[i])) {
				ret = -EFAULT;
				goto out;
			}

			connector = drm_connector_lookup(dev, out_id);
			if (!connector) {
				DRM_DEBUG_KMS("Connector id %d unknown\n",
						out_id);
				ret = -ENOENT;
				goto out;
			}
			DRM_DEBUG_KMS("[CONNECTOR:%d:%s]\n",
					connector->base.id,
					connector->name);

			connector_set[i] = connector;
		}
	}

	set.crtc = crtc;
	set.x = crtc_req->x;
	set.y = crtc_req->y;
	set.mode = mode;
	set.connectors = connector_set;
	set.num_connectors = crtc_req->count_connectors;
	set.fb = fb;
	ret = drm_mode_set_config_internal(&set);

out:
	if (fb)
		drm_framebuffer_unreference(fb);

	if (connector_set) {
		for (i = 0; i < crtc_req->count_connectors; i++) {
			if (connector_set[i])
				drm_connector_unreference(connector_set[i]);
		}
	}
	kfree(connector_set);
	drm_mode_destroy(dev, mode);
	drm_modeset_unlock_all(dev);
	return ret;
}

int drm_mode_crtc_set_obj_prop(struct drm_mode_object *obj,
			       struct drm_property *property,
			       uint64_t value)
{
	int ret = -EINVAL;
	struct drm_crtc *crtc = obj_to_crtc(obj);

	if (crtc->funcs->set_property)
		ret = crtc->funcs->set_property(crtc, property, value);
	if (!ret)
		drm_object_property_set_value(obj, property, value);

	return ret;
}

/**
 * drm_mode_create_dumb_ioctl - create a dumb backing storage buffer
 * @dev: DRM device
 * @data: ioctl data
 * @file_priv: DRM file info
 *
 * This creates a new dumb buffer in the driver's backing storage manager (GEM,
 * TTM or something else entirely) and returns the resulting buffer handle. This
 * handle can then be wrapped up into a framebuffer modeset object.
 *
 * Note that userspace is not allowed to use such objects for render
 * acceleration - drivers must create their own private ioctls for such a use
 * case.
 *
 * Called by the user via ioctl.
 *
 * Returns:
 * Zero on success, negative errno on failure.
 */
int drm_mode_create_dumb_ioctl(struct drm_device *dev,
			       void *data, struct drm_file *file_priv)
{
	struct drm_mode_create_dumb *args = data;
	u32 cpp, stride, size;

	if (!dev->driver->dumb_create)
		return -ENOSYS;
	if (!args->width || !args->height || !args->bpp)
		return -EINVAL;

	/* overflow checks for 32bit size calculations */
	/* NOTE: DIV_ROUND_UP() can overflow */
	cpp = DIV_ROUND_UP(args->bpp, 8);
	if (!cpp || cpp > 0xffffffffU / args->width)
		return -EINVAL;
	stride = cpp * args->width;
	if (args->height > 0xffffffffU / stride)
		return -EINVAL;

	/* test for wrap-around */
	size = args->height * stride;
	if (PAGE_ALIGN(size) == 0)
		return -EINVAL;

	/*
	 * handle, pitch and size are output parameters. Zero them out to
	 * prevent drivers from accidentally using uninitialized data. Since
	 * not all existing userspace is clearing these fields properly we
	 * cannot reject IOCTL with garbage in them.
	 */
	args->handle = 0;
	args->pitch = 0;
	args->size = 0;

	return dev->driver->dumb_create(file_priv, dev, args);
}

/**
 * drm_mode_mmap_dumb_ioctl - create an mmap offset for a dumb backing storage buffer
 * @dev: DRM device
 * @data: ioctl data
 * @file_priv: DRM file info
 *
 * Allocate an offset in the drm device node's address space to be able to
 * memory map a dumb buffer.
 *
 * Called by the user via ioctl.
 *
 * Returns:
 * Zero on success, negative errno on failure.
 */
int drm_mode_mmap_dumb_ioctl(struct drm_device *dev,
			     void *data, struct drm_file *file_priv)
{
	struct drm_mode_map_dumb *args = data;

	/* call driver ioctl to get mmap offset */
	if (!dev->driver->dumb_map_offset)
		return -ENOSYS;

	return dev->driver->dumb_map_offset(file_priv, dev, args->handle, &args->offset);
}

/**
 * drm_mode_destroy_dumb_ioctl - destroy a dumb backing strage buffer
 * @dev: DRM device
 * @data: ioctl data
 * @file_priv: DRM file info
 *
 * This destroys the userspace handle for the given dumb backing storage buffer.
 * Since buffer objects must be reference counted in the kernel a buffer object
 * won't be immediately freed if a framebuffer modeset object still uses it.
 *
 * Called by the user via ioctl.
 *
 * Returns:
 * Zero on success, negative errno on failure.
 */
int drm_mode_destroy_dumb_ioctl(struct drm_device *dev,
				void *data, struct drm_file *file_priv)
{
	struct drm_mode_destroy_dumb *args = data;

	if (!dev->driver->dumb_destroy)
		return -ENOSYS;

	return dev->driver->dumb_destroy(file_priv, dev, args->handle);
}

/**
 * DOC: Tile group
 *
 * Tile groups are used to represent tiled monitors with a unique
 * integer identifier. Tiled monitors using DisplayID v1.3 have
 * a unique 8-byte handle, we store this in a tile group, so we
 * have a common identifier for all tiles in a monitor group.
 */
static void drm_tile_group_free(struct kref *kref)
{
	struct drm_tile_group *tg = container_of(kref, struct drm_tile_group, refcount);
	struct drm_device *dev = tg->dev;
	mutex_lock(&dev->mode_config.idr_mutex);
	idr_remove(&dev->mode_config.tile_idr, tg->id);
	mutex_unlock(&dev->mode_config.idr_mutex);
	kfree(tg);
}

/**
 * drm_mode_put_tile_group - drop a reference to a tile group.
 * @dev: DRM device
 * @tg: tile group to drop reference to.
 *
 * drop reference to tile group and free if 0.
 */
void drm_mode_put_tile_group(struct drm_device *dev,
			     struct drm_tile_group *tg)
{
	kref_put(&tg->refcount, drm_tile_group_free);
}

/**
 * drm_mode_get_tile_group - get a reference to an existing tile group
 * @dev: DRM device
 * @topology: 8-bytes unique per monitor.
 *
 * Use the unique bytes to get a reference to an existing tile group.
 *
 * RETURNS:
 * tile group or NULL if not found.
 */
struct drm_tile_group *drm_mode_get_tile_group(struct drm_device *dev,
					       char topology[8])
{
	struct drm_tile_group *tg;
	int id;
	mutex_lock(&dev->mode_config.idr_mutex);
	idr_for_each_entry(&dev->mode_config.tile_idr, tg, id) {
		if (!memcmp(tg->group_data, topology, 8)) {
			if (!kref_get_unless_zero(&tg->refcount))
				tg = NULL;
			mutex_unlock(&dev->mode_config.idr_mutex);
			return tg;
		}
	}
	mutex_unlock(&dev->mode_config.idr_mutex);
	return NULL;
}
EXPORT_SYMBOL(drm_mode_get_tile_group);

/**
 * drm_mode_create_tile_group - create a tile group from a displayid description
 * @dev: DRM device
 * @topology: 8-bytes unique per monitor.
 *
 * Create a tile group for the unique monitor, and get a unique
 * identifier for the tile group.
 *
 * RETURNS:
 * new tile group or error.
 */
struct drm_tile_group *drm_mode_create_tile_group(struct drm_device *dev,
						  char topology[8])
{
	struct drm_tile_group *tg;
	int ret;

	tg = kzalloc(sizeof(*tg), GFP_KERNEL);
	if (!tg)
		return ERR_PTR(-ENOMEM);

	kref_init(&tg->refcount);
	memcpy(tg->group_data, topology, 8);
	tg->dev = dev;

	mutex_lock(&dev->mode_config.idr_mutex);
	ret = idr_alloc(&dev->mode_config.tile_idr, tg, 1, 0, GFP_KERNEL);
	if (ret >= 0) {
		tg->id = ret;
	} else {
		kfree(tg);
		tg = ERR_PTR(ret);
	}

	mutex_unlock(&dev->mode_config.idr_mutex);
	return tg;
}
EXPORT_SYMBOL(drm_mode_create_tile_group);