[PATCH 53/72] drm: implement page flipping support for planes

[Steve Longerbeam <slongerbeam@gmail.com>]

Planes like crtcs would benefit from having page flip event support.
With planes page flip it is now possible to synchronize changing a
framebuffer used by an overlay (or even cursor) plane with vertical
sync events.

A page flip in the primary plane is equivalent to a crtc page flip,
which suggests this ioctl could deprecate the crtc page flip ioctl
at some point in the future.

Signed-off-by: Steve Longerbeam <steve_longerbeam@mentor.com>
Signed-off-by: Dmitry Eremin-Solenikov <dmitry_eremin@mentor.com>
---
 drivers/gpu/drm/drm_crtc.c  |  241 +++++++++++++++++++++++++------------------
 drivers/gpu/drm/drm_ioctl.c |    1 +
 include/drm/drm_crtc.h      |   11 ++
 include/uapi/drm/drm.h      |    1 +
 include/uapi/drm/drm_mode.h |    8 ++
 5 files changed, 164 insertions(+), 98 deletions(-)

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index e79c8d3..53b5f87 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -2445,6 +2445,142 @@ int drm_mode_setplane(struct drm_device *dev, void *data,
 				 plane_req->src_w, plane_req->src_h);
 }
 
+int drm_mode_plane_page_flip_ioctl(struct drm_device *dev,
+				   void *data, struct drm_file *file_priv)
+{
+	struct drm_mode_plane_page_flip *page_flip = data;
+	struct drm_plane *plane;
+	struct drm_crtc *crtc;
+	struct drm_framebuffer *fb = NULL;
+	struct drm_pending_vblank_event *e = NULL;
+	unsigned long flags;
+	bool is_primary;
+	int ret;
+
+	if (page_flip->flags & ~DRM_MODE_PAGE_FLIP_FLAGS ||
+	    page_flip->reserved != 0)
+		return -EINVAL;
+
+	if ((page_flip->flags & DRM_MODE_PAGE_FLIP_ASYNC) &&
+	    !dev->mode_config.async_page_flip)
+		return -EINVAL;
+
+	plane = drm_plane_find(dev, page_flip->plane_id);
+	if (!plane)
+		return -ENOENT;
+
+	is_primary = (plane->type == DRM_PLANE_TYPE_PRIMARY);
+
+	drm_modeset_lock_all(dev);
+
+	if (plane->crtc == NULL || plane->fb == NULL) {
+		/* The crtc and/or framebuffer is currently unbound,
+		 * presumably due to a hotplug event, that userspace
+		 * has not yet discovered.
+		 */
+		ret = -EBUSY;
+		goto out;
+	}
+	crtc = plane->crtc;
+
+	if ((is_primary && crtc->funcs->page_flip == NULL) ||
+	    plane->funcs->page_flip == NULL) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	fb = drm_framebuffer_lookup(dev, page_flip->fb_id);
+	if (!fb) {
+		ret = -ENOENT;
+		goto out;
+	}
+
+	/*
+	 * If this is the primary plane (equivalent to a crtc page flip),
+	 * verify that the fb is valid for the bound crtc's viewport.
+	 * For overlay or cursor planes, the plane's page_flip op should
+	 * check that the fb is valid.
+	 */
+	if (is_primary) {
+		ret = drm_crtc_check_viewport(crtc, crtc->x, crtc->y,
+					      &crtc->mode, fb);
+		if (ret)
+			goto out;
+	}
+
+	if (plane->fb->pixel_format != fb->pixel_format) {
+		DRM_DEBUG_KMS("Page flip is not allowed to change frame buffer format.\n");
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (page_flip->flags & DRM_MODE_PAGE_FLIP_EVENT) {
+		ret = -ENOMEM;
+		spin_lock_irqsave(&dev->event_lock, flags);
+		if (file_priv->event_space < sizeof(e->event)) {
+			spin_unlock_irqrestore(&dev->event_lock, flags);
+			goto out;
+		}
+		file_priv->event_space -= sizeof(e->event);
+		spin_unlock_irqrestore(&dev->event_lock, flags);
+
+		e = kzalloc(sizeof(*e), GFP_KERNEL);
+		if (e == NULL) {
+			spin_lock_irqsave(&dev->event_lock, flags);
+			file_priv->event_space += sizeof(e->event);
+			spin_unlock_irqrestore(&dev->event_lock, flags);
+			goto out;
+		}
+
+		e->event.base.type = DRM_EVENT_FLIP_COMPLETE;
+		e->event.base.length = sizeof(e->event);
+		e->event.user_data = page_flip->user_data;
+		e->base.event = &e->event.base;
+		e->base.file_priv = file_priv;
+		e->base.destroy =
+			(void (*) (struct drm_pending_event *)) kfree;
+	}
+
+	plane->old_fb = plane->fb;
+
+	/* for now use crtc page_flip op, if this is the primary plane */
+	if (is_primary)
+		ret = crtc->funcs->page_flip(crtc, fb, e, page_flip->flags);
+	else
+		ret = plane->funcs->page_flip(plane, fb, e, page_flip->flags);
+
+	if (ret) {
+		if (page_flip->flags & DRM_MODE_PAGE_FLIP_EVENT) {
+			spin_lock_irqsave(&dev->event_lock, flags);
+			file_priv->event_space += sizeof(e->event);
+			spin_unlock_irqrestore(&dev->event_lock, flags);
+			kfree(e);
+		}
+		/* Keep the old fb, don't unref it. */
+		plane->old_fb = NULL;
+	} else {
+		/*
+		 * Warn if the driver hasn't properly updated the plane->fb
+		 * field to reflect that the new framebuffer is now used.
+		 * Failing to do so will screw with the reference counting
+		 * on framebuffers.
+		 */
+		WARN_ON(plane->fb != fb);
+		/* Unref only the old framebuffer. */
+		fb = NULL;
+	}
+
+out:
+	if (fb)
+		drm_framebuffer_unreference(fb);
+	if (plane->old_fb)
+		drm_framebuffer_unreference(plane->old_fb);
+	plane->old_fb = NULL;
+	drm_modeset_unlock_all(dev);
+
+	return ret;
+}
+
 /**
  * drm_mode_set_config_internal - helper to call ->set_config
  * @set: modeset config to set
@@ -4582,111 +4718,20 @@ int drm_mode_page_flip_ioctl(struct drm_device *dev,
 			     void *data, struct drm_file *file_priv)
 {
 	struct drm_mode_crtc_page_flip *page_flip = data;
+	struct drm_mode_plane_page_flip primary_pf = {0};
 	struct drm_crtc *crtc;
-	struct drm_framebuffer *fb = NULL;
-	struct drm_pending_vblank_event *e = NULL;
-	unsigned long flags;
-	int ret = -EINVAL;
-
-	if (page_flip->flags & ~DRM_MODE_PAGE_FLIP_FLAGS ||
-	    page_flip->reserved != 0)
-		return -EINVAL;
-
-	if ((page_flip->flags & DRM_MODE_PAGE_FLIP_ASYNC) && !dev->mode_config.async_page_flip)
-		return -EINVAL;
 
 	crtc = drm_crtc_find(dev, page_flip->crtc_id);
 	if (!crtc)
 		return -ENOENT;
 
-	drm_modeset_lock_crtc(crtc);
-	if (crtc->primary->fb == NULL) {
-		/* The framebuffer is currently unbound, presumably
-		 * due to a hotplug event, that userspace has not
-		 * yet discovered.
-		 */
-		ret = -EBUSY;
-		goto out;
-	}
-
-	if (crtc->funcs->page_flip == NULL)
-		goto out;
-
-	fb = drm_framebuffer_lookup(dev, page_flip->fb_id);
-	if (!fb) {
-		ret = -ENOENT;
-		goto out;
-	}
-
-	ret = drm_crtc_check_viewport(crtc, crtc->x, crtc->y, &crtc->mode, fb);
-	if (ret)
-		goto out;
-
-	if (crtc->primary->fb->pixel_format != fb->pixel_format) {
-		DRM_DEBUG_KMS("Page flip is not allowed to change frame buffer format.\n");
-		ret = -EINVAL;
-		goto out;
-	}
-
-	if (page_flip->flags & DRM_MODE_PAGE_FLIP_EVENT) {
-		ret = -ENOMEM;
-		spin_lock_irqsave(&dev->event_lock, flags);
-		if (file_priv->event_space < sizeof e->event) {
-			spin_unlock_irqrestore(&dev->event_lock, flags);
-			goto out;
-		}
-		file_priv->event_space -= sizeof e->event;
-		spin_unlock_irqrestore(&dev->event_lock, flags);
-
-		e = kzalloc(sizeof *e, GFP_KERNEL);
-		if (e == NULL) {
-			spin_lock_irqsave(&dev->event_lock, flags);
-			file_priv->event_space += sizeof e->event;
-			spin_unlock_irqrestore(&dev->event_lock, flags);
-			goto out;
-		}
-
-		e->event.base.type = DRM_EVENT_FLIP_COMPLETE;
-		e->event.base.length = sizeof e->event;
-		e->event.user_data = page_flip->user_data;
-		e->base.event = &e->event.base;
-		e->base.file_priv = file_priv;
-		e->base.destroy =
-			(void (*) (struct drm_pending_event *)) kfree;
-	}
-
-	crtc->primary->old_fb = crtc->primary->fb;
-	ret = crtc->funcs->page_flip(crtc, fb, e, page_flip->flags);
-	if (ret) {
-		if (page_flip->flags & DRM_MODE_PAGE_FLIP_EVENT) {
-			spin_lock_irqsave(&dev->event_lock, flags);
-			file_priv->event_space += sizeof e->event;
-			spin_unlock_irqrestore(&dev->event_lock, flags);
-			kfree(e);
-		}
-		/* Keep the old fb, don't unref it. */
-		crtc->primary->old_fb = NULL;
-	} else {
-		/*
-		 * Warn if the driver hasn't properly updated the crtc->fb
-		 * field to reflect that the new framebuffer is now used.
-		 * Failing to do so will screw with the reference counting
-		 * on framebuffers.
-		 */
-		WARN_ON(crtc->primary->fb != fb);
-		/* Unref only the old framebuffer. */
-		fb = NULL;
-	}
+	primary_pf.plane_id  = crtc->primary->base.id;
+	primary_pf.fb_id     = page_flip->fb_id;
+	primary_pf.flags     = page_flip->flags;
+	primary_pf.user_data = page_flip->user_data;
 
-out:
-	if (fb)
-		drm_framebuffer_unreference(fb);
-	if (crtc->primary->old_fb)
-		drm_framebuffer_unreference(crtc->primary->old_fb);
-	crtc->primary->old_fb = NULL;
-	drm_modeset_unlock_crtc(crtc);
-
-	return ret;
+	return drm_mode_plane_page_flip_ioctl(dev, (void *)&primary_pf,
+					      file_priv);
 }
 
 /**
diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
index 00587a1..2e60ee3 100644
--- a/drivers/gpu/drm/drm_ioctl.c
+++ b/drivers/gpu/drm/drm_ioctl.c
@@ -620,6 +620,7 @@ static const struct drm_ioctl_desc drm_ioctls[] = {
 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_OBJ_GETPROPERTIES, drm_mode_obj_get_properties_ioctl, DRM_CONTROL_ALLOW|DRM_UNLOCKED),
 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_OBJ_SETPROPERTY, drm_mode_obj_set_property_ioctl, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_CURSOR2, drm_mode_cursor2_ioctl, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
+	DRM_IOCTL_DEF(DRM_IOCTL_MODE_PLANE_PAGE_FLIP, drm_mode_plane_page_flip_ioctl, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
 };
 
 #define DRM_CORE_IOCTL_COUNT	ARRAY_SIZE( drm_ioctls )
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index c40070a..26d859b 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -571,6 +571,7 @@ struct drm_connector {
  * @disable_plane: shut down the plane
  * @destroy: clean up plane resources
  * @set_property: called when a property is changed
+ * @page_flip: initiate a page flip
  */
 struct drm_plane_funcs {
 	int (*update_plane)(struct drm_plane *plane,
@@ -585,6 +586,14 @@ struct drm_plane_funcs {
 
 	int (*set_property)(struct drm_plane *plane,
 			    struct drm_property *property, uint64_t val);
+
+	/*
+	 * See comment at drm_crtc_funcs.page_flip
+	 */
+	int (*page_flip)(struct drm_plane *plane,
+			 struct drm_framebuffer *fb,
+			 struct drm_pending_vblank_event *event,
+			 uint32_t flags);
 };
 
 enum drm_plane_type {
@@ -1105,6 +1114,8 @@ extern bool drm_detect_monitor_audio(struct edid *edid);
 extern bool drm_rgb_quant_range_selectable(struct edid *edid);
 extern int drm_mode_page_flip_ioctl(struct drm_device *dev,
 				    void *data, struct drm_file *file_priv);
+extern int drm_mode_plane_page_flip_ioctl(struct drm_device *dev,
+				    void *data, struct drm_file *file_priv);
 extern int drm_add_modes_noedid(struct drm_connector *connector,
 				int hdisplay, int vdisplay);
 extern void drm_set_preferred_mode(struct drm_connector *connector,
diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h
index b0b8556..48d9da6 100644
--- a/include/uapi/drm/drm.h
+++ b/include/uapi/drm/drm.h
@@ -777,6 +777,7 @@ struct drm_prime_handle {
 #define DRM_IOCTL_MODE_OBJ_GETPROPERTIES	DRM_IOWR(0xB9, struct drm_mode_obj_get_properties)
 #define DRM_IOCTL_MODE_OBJ_SETPROPERTY	DRM_IOWR(0xBA, struct drm_mode_obj_set_property)
 #define DRM_IOCTL_MODE_CURSOR2		DRM_IOWR(0xBB, struct drm_mode_cursor2)
+#define DRM_IOCTL_MODE_PLANE_PAGE_FLIP	DRM_IOWR(0xBC, struct drm_mode_plane_page_flip)
 
 /**
  * Device specific ioctls should only be in their respective headers
diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
index a0db2d4a..8d98cd0 100644
--- a/include/uapi/drm/drm_mode.h
+++ b/include/uapi/drm/drm_mode.h
@@ -488,6 +488,14 @@ struct drm_mode_crtc_page_flip {
 	__u64 user_data;
 };
 
+struct drm_mode_plane_page_flip {
+	__u32 plane_id;
+	__u32 fb_id;
+	__u32 flags;
+	__u32 reserved;
+	__u64 user_data;
+};
+
 /* create a dumb scanout buffer */
 struct drm_mode_create_dumb {
 	uint32_t height;
-- 
1.7.9.5

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