drm: Extract drm_framebuffer.[hc]

Also start with drm_modeset.h with the core bits, since we need
to untangle this mess somehow. That allows us to move the drm_modes.h
include to the right spot, except for the temporary connector status
enum. That will get fixed as soon as drm_connector.h exists.

v2: Rebase.

v3: Move drm_crtc_force_disable_all back again, that wasn't meant to
be moved (Sean).

v4: Rebase.

Cc: Sean Paul <seanpaul@chromium.org>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 796 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_framebuffer.c b/drivers/gpu/drm/drm_framebuffer.c
new file mode 100644
index 000000000000..74572c8a50b8
--- /dev/null
+++ b/drivers/gpu/drm/drm_framebuffer.c
@@ -0,0 +1,796 @@
+/*
+ * Copyright (c) 2016 Intel Corporation
+ *
+ * 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.
+ */
+
+#include <linux/export.h>
+#include <drm/drmP.h>
+#include <drm/drm_auth.h>
+#include <drm/drm_framebuffer.h>
+
+#include "drm_crtc_internal.h"
+
+/**
+ * drm_mode_addfb - add an FB to the graphics configuration
+ * @dev: drm device for the ioctl
+ * @data: data pointer for the ioctl
+ * @file_priv: drm file for the ioctl call
+ *
+ * Add a new FB to the specified CRTC, given a user request. This is the
+ * original addfb ioctl which only supported RGB formats.
+ *
+ * Called by the user via ioctl.
+ *
+ * Returns:
+ * Zero on success, negative errno on failure.
+ */
+int drm_mode_addfb(struct drm_device *dev,
+		   void *data, struct drm_file *file_priv)
+{
+	struct drm_mode_fb_cmd *or = data;
+	struct drm_mode_fb_cmd2 r = {};
+	int ret;
+
+	/* convert to new format and call new ioctl */
+	r.fb_id = or->fb_id;
+	r.width = or->width;
+	r.height = or->height;
+	r.pitches[0] = or->pitch;
+	r.pixel_format = drm_mode_legacy_fb_format(or->bpp, or->depth);
+	r.handles[0] = or->handle;
+
+	ret = drm_mode_addfb2(dev, &r, file_priv);
+	if (ret)
+		return ret;
+
+	or->fb_id = r.fb_id;
+
+	return 0;
+}
+
+static int format_check(const struct drm_mode_fb_cmd2 *r)
+{
+	uint32_t format = r->pixel_format & ~DRM_FORMAT_BIG_ENDIAN;
+	char *format_name;
+
+	switch (format) {
+	case DRM_FORMAT_C8:
+	case DRM_FORMAT_RGB332:
+	case DRM_FORMAT_BGR233:
+	case DRM_FORMAT_XRGB4444:
+	case DRM_FORMAT_XBGR4444:
+	case DRM_FORMAT_RGBX4444:
+	case DRM_FORMAT_BGRX4444:
+	case DRM_FORMAT_ARGB4444:
+	case DRM_FORMAT_ABGR4444:
+	case DRM_FORMAT_RGBA4444:
+	case DRM_FORMAT_BGRA4444:
+	case DRM_FORMAT_XRGB1555:
+	case DRM_FORMAT_XBGR1555:
+	case DRM_FORMAT_RGBX5551:
+	case DRM_FORMAT_BGRX5551:
+	case DRM_FORMAT_ARGB1555:
+	case DRM_FORMAT_ABGR1555:
+	case DRM_FORMAT_RGBA5551:
+	case DRM_FORMAT_BGRA5551:
+	case DRM_FORMAT_RGB565:
+	case DRM_FORMAT_BGR565:
+	case DRM_FORMAT_RGB888:
+	case DRM_FORMAT_BGR888:
+	case DRM_FORMAT_XRGB8888:
+	case DRM_FORMAT_XBGR8888:
+	case DRM_FORMAT_RGBX8888:
+	case DRM_FORMAT_BGRX8888:
+	case DRM_FORMAT_ARGB8888:
+	case DRM_FORMAT_ABGR8888:
+	case DRM_FORMAT_RGBA8888:
+	case DRM_FORMAT_BGRA8888:
+	case DRM_FORMAT_XRGB2101010:
+	case DRM_FORMAT_XBGR2101010:
+	case DRM_FORMAT_RGBX1010102:
+	case DRM_FORMAT_BGRX1010102:
+	case DRM_FORMAT_ARGB2101010:
+	case DRM_FORMAT_ABGR2101010:
+	case DRM_FORMAT_RGBA1010102:
+	case DRM_FORMAT_BGRA1010102:
+	case DRM_FORMAT_YUYV:
+	case DRM_FORMAT_YVYU:
+	case DRM_FORMAT_UYVY:
+	case DRM_FORMAT_VYUY:
+	case DRM_FORMAT_AYUV:
+	case DRM_FORMAT_NV12:
+	case DRM_FORMAT_NV21:
+	case DRM_FORMAT_NV16:
+	case DRM_FORMAT_NV61:
+	case DRM_FORMAT_NV24:
+	case DRM_FORMAT_NV42:
+	case DRM_FORMAT_YUV410:
+	case DRM_FORMAT_YVU410:
+	case DRM_FORMAT_YUV411:
+	case DRM_FORMAT_YVU411:
+	case DRM_FORMAT_YUV420:
+	case DRM_FORMAT_YVU420:
+	case DRM_FORMAT_YUV422:
+	case DRM_FORMAT_YVU422:
+	case DRM_FORMAT_YUV444:
+	case DRM_FORMAT_YVU444:
+		return 0;
+	default:
+		format_name = drm_get_format_name(r->pixel_format);
+		DRM_DEBUG_KMS("invalid pixel format %s\n", format_name);
+		kfree(format_name);
+		return -EINVAL;
+	}
+}
+
+static int framebuffer_check(const struct drm_mode_fb_cmd2 *r)
+{
+	int ret, hsub, vsub, num_planes, i;
+
+	ret = format_check(r);
+	if (ret) {
+		char *format_name = drm_get_format_name(r->pixel_format);
+		DRM_DEBUG_KMS("bad framebuffer format %s\n", format_name);
+		kfree(format_name);
+		return ret;
+	}
+
+	hsub = drm_format_horz_chroma_subsampling(r->pixel_format);
+	vsub = drm_format_vert_chroma_subsampling(r->pixel_format);
+	num_planes = drm_format_num_planes(r->pixel_format);
+
+	if (r->width == 0 || r->width % hsub) {
+		DRM_DEBUG_KMS("bad framebuffer width %u\n", r->width);
+		return -EINVAL;
+	}
+
+	if (r->height == 0 || r->height % vsub) {
+		DRM_DEBUG_KMS("bad framebuffer height %u\n", r->height);
+		return -EINVAL;
+	}
+
+	for (i = 0; i < num_planes; i++) {
+		unsigned int width = r->width / (i != 0 ? hsub : 1);
+		unsigned int height = r->height / (i != 0 ? vsub : 1);
+		unsigned int cpp = drm_format_plane_cpp(r->pixel_format, i);
+
+		if (!r->handles[i]) {
+			DRM_DEBUG_KMS("no buffer object handle for plane %d\n", i);
+			return -EINVAL;
+		}
+
+		if ((uint64_t) width * cpp > UINT_MAX)
+			return -ERANGE;
+
+		if ((uint64_t) height * r->pitches[i] + r->offsets[i] > UINT_MAX)
+			return -ERANGE;
+
+		if (r->pitches[i] < width * cpp) {
+			DRM_DEBUG_KMS("bad pitch %u for plane %d\n", r->pitches[i], i);
+			return -EINVAL;
+		}
+
+		if (r->modifier[i] && !(r->flags & DRM_MODE_FB_MODIFIERS)) {
+			DRM_DEBUG_KMS("bad fb modifier %llu for plane %d\n",
+				      r->modifier[i], i);
+			return -EINVAL;
+		}
+
+		/* modifier specific checks: */
+		switch (r->modifier[i]) {
+		case DRM_FORMAT_MOD_SAMSUNG_64_32_TILE:
+			/* NOTE: the pitch restriction may be lifted later if it turns
+			 * out that no hw has this restriction:
+			 */
+			if (r->pixel_format != DRM_FORMAT_NV12 ||
+					width % 128 || height % 32 ||
+					r->pitches[i] % 128) {
+				DRM_DEBUG_KMS("bad modifier data for plane %d\n", i);
+				return -EINVAL;
+			}
+			break;
+
+		default:
+			break;
+		}
+	}
+
+	for (i = num_planes; i < 4; i++) {
+		if (r->modifier[i]) {
+			DRM_DEBUG_KMS("non-zero modifier for unused plane %d\n", i);
+			return -EINVAL;
+		}
+
+		/* Pre-FB_MODIFIERS userspace didn't clear the structs properly. */
+		if (!(r->flags & DRM_MODE_FB_MODIFIERS))
+			continue;
+
+		if (r->handles[i]) {
+			DRM_DEBUG_KMS("buffer object handle for unused plane %d\n", i);
+			return -EINVAL;
+		}
+
+		if (r->pitches[i]) {
+			DRM_DEBUG_KMS("non-zero pitch for unused plane %d\n", i);
+			return -EINVAL;
+		}
+
+		if (r->offsets[i]) {
+			DRM_DEBUG_KMS("non-zero offset for unused plane %d\n", i);
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+struct drm_framebuffer *
+drm_internal_framebuffer_create(struct drm_device *dev,
+				const struct drm_mode_fb_cmd2 *r,
+				struct drm_file *file_priv)
+{
+	struct drm_mode_config *config = &dev->mode_config;
+	struct drm_framebuffer *fb;
+	int ret;
+
+	if (r->flags & ~(DRM_MODE_FB_INTERLACED | DRM_MODE_FB_MODIFIERS)) {
+		DRM_DEBUG_KMS("bad framebuffer flags 0x%08x\n", r->flags);
+		return ERR_PTR(-EINVAL);
+	}
+
+	if ((config->min_width > r->width) || (r->width > config->max_width)) {
+		DRM_DEBUG_KMS("bad framebuffer width %d, should be >= %d && <= %d\n",
+			  r->width, config->min_width, config->max_width);
+		return ERR_PTR(-EINVAL);
+	}
+	if ((config->min_height > r->height) || (r->height > config->max_height)) {
+		DRM_DEBUG_KMS("bad framebuffer height %d, should be >= %d && <= %d\n",
+			  r->height, config->min_height, config->max_height);
+		return ERR_PTR(-EINVAL);
+	}
+
+	if (r->flags & DRM_MODE_FB_MODIFIERS &&
+	    !dev->mode_config.allow_fb_modifiers) {
+		DRM_DEBUG_KMS("driver does not support fb modifiers\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	ret = framebuffer_check(r);
+	if (ret)
+		return ERR_PTR(ret);
+
+	fb = dev->mode_config.funcs->fb_create(dev, file_priv, r);
+	if (IS_ERR(fb)) {
+		DRM_DEBUG_KMS("could not create framebuffer\n");
+		return fb;
+	}
+
+	return fb;
+}
+
+/**
+ * drm_mode_addfb2 - add an FB to the graphics configuration
+ * @dev: drm device for the ioctl
+ * @data: data pointer for the ioctl
+ * @file_priv: drm file for the ioctl call
+ *
+ * Add a new FB to the specified CRTC, given a user request with format. This is
+ * the 2nd version of the addfb ioctl, which supports multi-planar framebuffers
+ * and uses fourcc codes as pixel format specifiers.
+ *
+ * Called by the user via ioctl.
+ *
+ * Returns:
+ * Zero on success, negative errno on failure.
+ */
+int drm_mode_addfb2(struct drm_device *dev,
+		    void *data, struct drm_file *file_priv)
+{
+	struct drm_mode_fb_cmd2 *r = data;
+	struct drm_framebuffer *fb;
+
+	if (!drm_core_check_feature(dev, DRIVER_MODESET))
+		return -EINVAL;
+
+	fb = drm_internal_framebuffer_create(dev, r, file_priv);
+	if (IS_ERR(fb))
+		return PTR_ERR(fb);
+
+	DRM_DEBUG_KMS("[FB:%d]\n", fb->base.id);
+	r->fb_id = fb->base.id;
+
+	/* Transfer ownership to the filp for reaping on close */
+	mutex_lock(&file_priv->fbs_lock);
+	list_add(&fb->filp_head, &file_priv->fbs);
+	mutex_unlock(&file_priv->fbs_lock);
+
+	return 0;
+}
+
+struct drm_mode_rmfb_work {
+	struct work_struct work;
+	struct list_head fbs;
+};
+
+static void drm_mode_rmfb_work_fn(struct work_struct *w)
+{
+	struct drm_mode_rmfb_work *arg = container_of(w, typeof(*arg), work);
+
+	while (!list_empty(&arg->fbs)) {
+		struct drm_framebuffer *fb =
+			list_first_entry(&arg->fbs, typeof(*fb), filp_head);
+
+		list_del_init(&fb->filp_head);
+		drm_framebuffer_remove(fb);
+	}
+}
+
+/**
+ * drm_mode_rmfb - remove an FB from the configuration
+ * @dev: drm device for the ioctl
+ * @data: data pointer for the ioctl
+ * @file_priv: drm file for the ioctl call
+ *
+ * Remove the FB specified by the user.
+ *
+ * Called by the user via ioctl.
+ *
+ * Returns:
+ * Zero on success, negative errno on failure.
+ */
+int drm_mode_rmfb(struct drm_device *dev,
+		   void *data, struct drm_file *file_priv)
+{
+	struct drm_framebuffer *fb = NULL;
+	struct drm_framebuffer *fbl = NULL;
+	uint32_t *id = data;
+	int found = 0;
+
+	if (!drm_core_check_feature(dev, DRIVER_MODESET))
+		return -EINVAL;
+
+	fb = drm_framebuffer_lookup(dev, *id);
+	if (!fb)
+		return -ENOENT;
+
+	mutex_lock(&file_priv->fbs_lock);
+	list_for_each_entry(fbl, &file_priv->fbs, filp_head)
+		if (fb == fbl)
+			found = 1;
+	if (!found) {
+		mutex_unlock(&file_priv->fbs_lock);
+		goto fail_unref;
+	}
+
+	list_del_init(&fb->filp_head);
+	mutex_unlock(&file_priv->fbs_lock);
+
+	/* drop the reference we picked up in framebuffer lookup */
+	drm_framebuffer_unreference(fb);
+
+	/*
+	 * we now own the reference that was stored in the fbs list
+	 *
+	 * drm_framebuffer_remove may fail with -EINTR on pending signals,
+	 * so run this in a separate stack as there's no way to correctly
+	 * handle this after the fb is already removed from the lookup table.
+	 */
+	if (drm_framebuffer_read_refcount(fb) > 1) {
+		struct drm_mode_rmfb_work arg;
+
+		INIT_WORK_ONSTACK(&arg.work, drm_mode_rmfb_work_fn);
+		INIT_LIST_HEAD(&arg.fbs);
+		list_add_tail(&fb->filp_head, &arg.fbs);
+
+		schedule_work(&arg.work);
+		flush_work(&arg.work);
+		destroy_work_on_stack(&arg.work);
+	} else
+		drm_framebuffer_unreference(fb);
+
+	return 0;
+
+fail_unref:
+	drm_framebuffer_unreference(fb);
+	return -ENOENT;
+}
+
+/**
+ * drm_mode_getfb - get FB info
+ * @dev: drm device for the ioctl
+ * @data: data pointer for the ioctl
+ * @file_priv: drm file for the ioctl call
+ *
+ * Lookup the FB given its ID and return info about it.
+ *
+ * Called by the user via ioctl.
+ *
+ * Returns:
+ * Zero on success, negative errno on failure.
+ */
+int drm_mode_getfb(struct drm_device *dev,
+		   void *data, struct drm_file *file_priv)
+{
+	struct drm_mode_fb_cmd *r = data;
+	struct drm_framebuffer *fb;
+	int ret;
+
+	if (!drm_core_check_feature(dev, DRIVER_MODESET))
+		return -EINVAL;
+
+	fb = drm_framebuffer_lookup(dev, r->fb_id);
+	if (!fb)
+		return -ENOENT;
+
+	r->height = fb->height;
+	r->width = fb->width;
+	r->depth = fb->depth;
+	r->bpp = fb->bits_per_pixel;
+	r->pitch = fb->pitches[0];
+	if (fb->funcs->create_handle) {
+		if (drm_is_current_master(file_priv) || capable(CAP_SYS_ADMIN) ||
+		    drm_is_control_client(file_priv)) {
+			ret = fb->funcs->create_handle(fb, file_priv,
+						       &r->handle);
+		} else {
+			/* GET_FB() is an unprivileged ioctl so we must not
+			 * return a buffer-handle to non-master processes! For
+			 * backwards-compatibility reasons, we cannot make
+			 * GET_FB() privileged, so just return an invalid handle
+			 * for non-masters. */
+			r->handle = 0;
+			ret = 0;
+		}
+	} else {
+		ret = -ENODEV;
+	}
+
+	drm_framebuffer_unreference(fb);
+
+	return ret;
+}
+
+/**
+ * drm_mode_dirtyfb_ioctl - flush frontbuffer rendering on an FB
+ * @dev: drm device for the ioctl
+ * @data: data pointer for the ioctl
+ * @file_priv: drm file for the ioctl call
+ *
+ * Lookup the FB and flush out the damaged area supplied by userspace as a clip
+ * rectangle list. Generic userspace which does frontbuffer rendering must call
+ * this ioctl to flush out the changes on manual-update display outputs, e.g.
+ * usb display-link, mipi manual update panels or edp panel self refresh modes.
+ *
+ * Modesetting drivers which always update the frontbuffer do not need to
+ * implement the corresponding ->dirty framebuffer callback.
+ *
+ * Called by the user via ioctl.
+ *
+ * Returns:
+ * Zero on success, negative errno on failure.
+ */
+int drm_mode_dirtyfb_ioctl(struct drm_device *dev,
+			   void *data, struct drm_file *file_priv)
+{
+	struct drm_clip_rect __user *clips_ptr;
+	struct drm_clip_rect *clips = NULL;
+	struct drm_mode_fb_dirty_cmd *r = data;
+	struct drm_framebuffer *fb;
+	unsigned flags;
+	int num_clips;
+	int ret;
+
+	if (!drm_core_check_feature(dev, DRIVER_MODESET))
+		return -EINVAL;
+
+	fb = drm_framebuffer_lookup(dev, r->fb_id);
+	if (!fb)
+		return -ENOENT;
+
+	num_clips = r->num_clips;
+	clips_ptr = (struct drm_clip_rect __user *)(unsigned long)r->clips_ptr;
+
+	if (!num_clips != !clips_ptr) {
+		ret = -EINVAL;
+		goto out_err1;
+	}
+
+	flags = DRM_MODE_FB_DIRTY_FLAGS & r->flags;
+
+	/* If userspace annotates copy, clips must come in pairs */
+	if (flags & DRM_MODE_FB_DIRTY_ANNOTATE_COPY && (num_clips % 2)) {
+		ret = -EINVAL;
+		goto out_err1;
+	}
+
+	if (num_clips && clips_ptr) {
+		if (num_clips < 0 || num_clips > DRM_MODE_FB_DIRTY_MAX_CLIPS) {
+			ret = -EINVAL;
+			goto out_err1;
+		}
+		clips = kcalloc(num_clips, sizeof(*clips), GFP_KERNEL);
+		if (!clips) {
+			ret = -ENOMEM;
+			goto out_err1;
+		}
+
+		ret = copy_from_user(clips, clips_ptr,
+				     num_clips * sizeof(*clips));
+		if (ret) {
+			ret = -EFAULT;
+			goto out_err2;
+		}
+	}
+
+	if (fb->funcs->dirty) {
+		ret = fb->funcs->dirty(fb, file_priv, flags, r->color,
+				       clips, num_clips);
+	} else {
+		ret = -ENOSYS;
+	}
+
+out_err2:
+	kfree(clips);
+out_err1:
+	drm_framebuffer_unreference(fb);
+
+	return ret;
+}
+
+/**
+ * drm_fb_release - remove and free the FBs on this file
+ * @priv: drm file for the ioctl
+ *
+ * Destroy all the FBs associated with @filp.
+ *
+ * Called by the user via ioctl.
+ *
+ * Returns:
+ * Zero on success, negative errno on failure.
+ */
+void drm_fb_release(struct drm_file *priv)
+{
+	struct drm_framebuffer *fb, *tfb;
+	struct drm_mode_rmfb_work arg;
+
+	INIT_LIST_HEAD(&arg.fbs);
+
+	/*
+	 * When the file gets released that means no one else can access the fb
+	 * list any more, so no need to grab fpriv->fbs_lock. And we need to
+	 * avoid upsetting lockdep since the universal cursor code adds a
+	 * framebuffer while holding mutex locks.
+	 *
+	 * Note that a real deadlock between fpriv->fbs_lock and the modeset
+	 * locks is impossible here since no one else but this function can get
+	 * at it any more.
+	 */
+	list_for_each_entry_safe(fb, tfb, &priv->fbs, filp_head) {
+		if (drm_framebuffer_read_refcount(fb) > 1) {
+			list_move_tail(&fb->filp_head, &arg.fbs);
+		} else {
+			list_del_init(&fb->filp_head);
+
+			/* This drops the fpriv->fbs reference. */
+			drm_framebuffer_unreference(fb);
+		}
+	}
+
+	if (!list_empty(&arg.fbs)) {
+		INIT_WORK_ONSTACK(&arg.work, drm_mode_rmfb_work_fn);
+
+		schedule_work(&arg.work);
+		flush_work(&arg.work);
+		destroy_work_on_stack(&arg.work);
+	}
+}
+
+void drm_framebuffer_free(struct kref *kref)
+{
+	struct drm_framebuffer *fb =
+			container_of(kref, struct drm_framebuffer, base.refcount);
+	struct drm_device *dev = fb->dev;
+
+	/*
+	 * The lookup idr holds a weak reference, which has not necessarily been
+	 * removed at this point. Check for that.
+	 */
+	drm_mode_object_unregister(dev, &fb->base);
+
+	fb->funcs->destroy(fb);
+}
+
+/**
+ * drm_framebuffer_init - initialize a framebuffer
+ * @dev: DRM device
+ * @fb: framebuffer to be initialized
+ * @funcs: ... with these functions
+ *
+ * Allocates an ID for the framebuffer's parent mode object, sets its mode
+ * functions & device file and adds it to the master fd list.
+ *
+ * IMPORTANT:
+ * This functions publishes the fb and makes it available for concurrent access
+ * by other users. Which means by this point the fb _must_ be fully set up -
+ * since all the fb attributes are invariant over its lifetime, no further
+ * locking but only correct reference counting is required.
+ *
+ * Returns:
+ * Zero on success, error code on failure.
+ */
+int drm_framebuffer_init(struct drm_device *dev, struct drm_framebuffer *fb,
+			 const struct drm_framebuffer_funcs *funcs)
+{
+	int ret;
+
+	INIT_LIST_HEAD(&fb->filp_head);
+	fb->dev = dev;
+	fb->funcs = funcs;
+
+	ret = drm_mode_object_get_reg(dev, &fb->base, DRM_MODE_OBJECT_FB,
+				      false, drm_framebuffer_free);
+	if (ret)
+		goto out;
+
+	mutex_lock(&dev->mode_config.fb_lock);
+	dev->mode_config.num_fb++;
+	list_add(&fb->head, &dev->mode_config.fb_list);
+	mutex_unlock(&dev->mode_config.fb_lock);
+
+	drm_mode_object_register(dev, &fb->base);
+out:
+	return ret;
+}
+EXPORT_SYMBOL(drm_framebuffer_init);
+
+/**
+ * drm_framebuffer_lookup - look up a drm framebuffer and grab a reference
+ * @dev: drm device
+ * @id: id of the fb object
+ *
+ * If successful, this grabs an additional reference to the framebuffer -
+ * callers need to make sure to eventually unreference the returned framebuffer
+ * again, using @drm_framebuffer_unreference.
+ */
+struct drm_framebuffer *drm_framebuffer_lookup(struct drm_device *dev,
+					       uint32_t id)
+{
+	struct drm_mode_object *obj;
+	struct drm_framebuffer *fb = NULL;
+
+	obj = __drm_mode_object_find(dev, id, DRM_MODE_OBJECT_FB);
+	if (obj)
+		fb = obj_to_fb(obj);
+	return fb;
+}
+EXPORT_SYMBOL(drm_framebuffer_lookup);
+
+/**
+ * drm_framebuffer_unregister_private - unregister a private fb from the lookup idr
+ * @fb: fb to unregister
+ *
+ * Drivers need to call this when cleaning up driver-private framebuffers, e.g.
+ * those used for fbdev. Note that the caller must hold a reference of it's own,
+ * i.e. the object may not be destroyed through this call (since it'll lead to a
+ * locking inversion).
+ */
+void drm_framebuffer_unregister_private(struct drm_framebuffer *fb)
+{
+	struct drm_device *dev;
+
+	if (!fb)
+		return;
+
+	dev = fb->dev;
+
+	/* Mark fb as reaped and drop idr ref. */
+	drm_mode_object_unregister(dev, &fb->base);
+}
+EXPORT_SYMBOL(drm_framebuffer_unregister_private);
+
+/**
+ * drm_framebuffer_cleanup - remove a framebuffer object
+ * @fb: framebuffer to remove
+ *
+ * Cleanup framebuffer. This function is intended to be used from the drivers
+ * ->destroy callback. It can also be used to clean up driver private
+ * framebuffers embedded into a larger structure.
+ *
+ * Note that this function does not remove the fb from active usuage - if it is
+ * still used anywhere, hilarity can ensue since userspace could call getfb on
+ * the id and get back -EINVAL. Obviously no concern at driver unload time.
+ *
+ * Also, the framebuffer will not be removed from the lookup idr - for
+ * user-created framebuffers this will happen in in the rmfb ioctl. For
+ * driver-private objects (e.g. for fbdev) drivers need to explicitly call
+ * drm_framebuffer_unregister_private.
+ */
+void drm_framebuffer_cleanup(struct drm_framebuffer *fb)
+{
+	struct drm_device *dev = fb->dev;
+
+	mutex_lock(&dev->mode_config.fb_lock);
+	list_del(&fb->head);
+	dev->mode_config.num_fb--;
+	mutex_unlock(&dev->mode_config.fb_lock);
+}
+EXPORT_SYMBOL(drm_framebuffer_cleanup);
+
+/**
+ * drm_framebuffer_remove - remove and unreference a framebuffer object
+ * @fb: framebuffer to remove
+ *
+ * Scans all the CRTCs and planes in @dev's mode_config.  If they're
+ * using @fb, removes it, setting it to NULL. Then drops the reference to the
+ * passed-in framebuffer. Might take the modeset locks.
+ *
+ * Note that this function optimizes the cleanup away if the caller holds the
+ * last reference to the framebuffer. It is also guaranteed to not take the
+ * modeset locks in this case.
+ */
+void drm_framebuffer_remove(struct drm_framebuffer *fb)
+{
+	struct drm_device *dev;
+	struct drm_crtc *crtc;
+	struct drm_plane *plane;
+
+	if (!fb)
+		return;
+
+	dev = fb->dev;
+
+	WARN_ON(!list_empty(&fb->filp_head));
+
+	/*
+	 * drm ABI mandates that we remove any deleted framebuffers from active
+	 * useage. But since most sane clients only remove framebuffers they no
+	 * longer need, try to optimize this away.
+	 *
+	 * Since we're holding a reference ourselves, observing a refcount of 1
+	 * means that we're the last holder and can skip it. Also, the refcount
+	 * can never increase from 1 again, so we don't need any barriers or
+	 * locks.
+	 *
+	 * Note that userspace could try to race with use and instate a new
+	 * usage _after_ we've cleared all current ones. End result will be an
+	 * in-use fb with fb-id == 0. Userspace is allowed to shoot its own foot
+	 * in this manner.
+	 */
+	if (drm_framebuffer_read_refcount(fb) > 1) {
+		drm_modeset_lock_all(dev);
+		/* remove from any CRTC */
+		drm_for_each_crtc(crtc, dev) {
+			if (crtc->primary->fb == fb) {
+				/* should turn off the crtc */
+				if (drm_crtc_force_disable(crtc))
+					DRM_ERROR("failed to reset crtc %p when fb was deleted\n", crtc);
+			}
+		}
+
+		drm_for_each_plane(plane, dev) {
+			if (plane->fb == fb)
+				drm_plane_force_disable(plane);
+		}
+		drm_modeset_unlock_all(dev);
+	}
+
+	drm_framebuffer_unreference(fb);
+}
+EXPORT_SYMBOL(drm_framebuffer_remove);