[v5,1/5] drm: add generic zpos property

diff --git a/Documentation/DocBook/gpu.tmpl b/Documentation/DocBook/gpu.tmpl
index a8669330b456..ae7d913adf60 100644
--- a/Documentation/DocBook/gpu.tmpl
+++ b/Documentation/DocBook/gpu.tmpl
@@ -1816,7 +1816,7 @@  void intel_crt_init(struct drm_device *dev)
 	<td valign="top" >Description/Restrictions</td>
 	</tr>
 	<tr>
-	<td rowspan="37" valign="top" >DRM</td>
+	<td rowspan="38" valign="top" >DRM</td>
 	<td valign="top" >Generic</td>
 	<td valign="top" >“rotation”</td>
 	<td valign="top" >BITMASK</td>
@@ -2068,7 +2068,7 @@  void intel_crt_init(struct drm_device *dev)
 	<td valign="top" >property to suggest an Y offset for a connector</td>
 	</tr>
 	<tr>
-	<td rowspan="3" valign="top" >Optional</td>
+	<td rowspan="4" valign="top" >Optional</td>
 	<td valign="top" >“scaling mode”</td>
 	<td valign="top" >ENUM</td>
 	<td valign="top" >{ "None", "Full", "Center", "Full aspect" }</td>
@@ -2092,6 +2092,16 @@  void intel_crt_init(struct drm_device *dev)
 	<td valign="top" >TBD</td>
 	</tr>
 	<tr>
+	<td valign="top" > "zpos" </td>
+	<td valign="top" >RANGE</td>
+	<td valign="top" >Min=0, Max= driver dependent</td>
+	<td valign="top" >Plane</td>
+	<td valign="top" >Plane's 'z' position during blending operation (0 for background, highest for frontmost).
+		If two planes assigned to same CRTC have equal zpos values, the plane with higher plane
+		id is treated as closer to front. Can be IMMUTABLE if driver doesn't support changing
+		planes' order. Exact value range is driver dependent.</td>
+	</tr>
+	<tr>
 	<td rowspan="20" valign="top" >i915</td>
 	<td rowspan="2" valign="top" >Generic</td>
 	<td valign="top" >"Broadcast RGB"</td>
diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index 61766dec6a8d..eeefaba1c092 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -2,7 +2,7 @@ 
 # Makefile for the drm device driver.  This driver provides support for the
 # Direct Rendering Infrastructure (DRI) in XFree86 4.1.0 and higher.
 
-drm-y       :=	drm_auth.o drm_bufs.o drm_cache.o \
+drm-y       :=	drm_auth.o drm_bufs.o drm_blend.o drm_cache.o \
 		drm_context.o drm_dma.o \
 		drm_fops.o drm_gem.o drm_ioctl.o drm_irq.o \
 		drm_lock.o drm_memory.o drm_drv.o drm_vm.o \
diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index 3f74193885f1..a19201efb7d1 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -630,6 +630,8 @@  int drm_atomic_plane_set_property(struct drm_plane *plane,
 		state->src_h = val;
 	} else if (property == config->rotation_property) {
 		state->rotation = val;
+	} else if (property == config->zpos_property) {
+		state->zpos = val;
 	} else if (plane->funcs->atomic_set_property) {
 		return plane->funcs->atomic_set_property(plane, state,
 				property, val);
@@ -686,6 +688,8 @@  drm_atomic_plane_get_property(struct drm_plane *plane,
 		*val = state->src_h;
 	} else if (property == config->rotation_property) {
 		*val = state->rotation;
+	} else if (property == config->zpos_property) {
+		*val = state->zpos;
 	} else if (plane->funcs->atomic_get_property) {
 		return plane->funcs->atomic_get_property(plane, state, property, val);
 	} else {
diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 53db2d9120be..9fbfb672b317 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -32,6 +32,8 @@ 
 #include <drm/drm_atomic_helper.h>
 #include <linux/fence.h>
 
+#include "drm_crtc_internal.h"
+
 /**
  * DOC: overview
  *
@@ -530,6 +532,10 @@  drm_atomic_helper_check_planes(struct drm_device *dev,
 	struct drm_plane_state *plane_state;
 	int i, ret = 0;
 
+	ret = drm_atomic_helper_normalize_zpos(dev, state);
+	if (ret)
+		return ret;
+
 	for_each_plane_in_state(state, plane, plane_state, i) {
 		const struct drm_plane_helper_funcs *funcs;
 
diff --git a/drivers/gpu/drm/drm_blend.c b/drivers/gpu/drm/drm_blend.c
new file mode 100644
index 000000000000..cdcb647c8ed9
--- /dev/null
+++ b/drivers/gpu/drm/drm_blend.c
@@ -0,0 +1,227 @@ 
+/*
+ * Copyright (C) 2016 Samsung Electronics Co.Ltd
+ * Authors:
+ *	Marek Szyprowski <m.szyprowski@samsung.com>
+ *
+ * DRM core plane blending 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.
+ */
+#include <linux/slab.h>
+#include <linux/sort.h>
+#include <linux/export.h>
+#include <drm/drmP.h>
+#include <drm/drm_crtc.h>
+#include <drm/drm_atomic.h>
+
+#include "drm_internal.h"
+
+/**
+ * drm_mode_create_zpos_property - create muttable zpos property
+ * @dev: DRM device
+ * @min: minimal possible value of zpos property
+ * @max: maximal possible value of zpos property
+ *
+ * This function initializes generic muttable zpos property and enables support
+ * for it in drm core. Drivers can then attach this property to planes to enable
+ * support for configurable planes arrangement during blending operation.
+ * Once muttable zpos property has been enabled, the DRM core will automatically
+ * calculate drm_plane_state->normalized_zpos values. Usually min should be set
+ * to 0 and max to maximal number of planes for given crtc - 1.
+ *
+ * If zpos of some planes cannot be changed (like fixed backgroud or
+ * cursor/topmost planes), driver should adjust min/max values and assign those
+ * planes immutable zpos property with lower or higher values (for more
+ * information, see drm_mode_create_zpos_immutable_property() function). In such
+ * case driver should also assign proper initial zpos values for all planes in
+ * its plane_reset() callback, so the planes will be always sorted properly.
+ *
+ * Returns:
+ * Zero on success, negative errno on failure.
+ */
+int drm_mode_create_zpos_property(struct drm_device *dev, unsigned int min,
+				  unsigned int max)
+{
+	struct drm_property *prop;
+
+	prop = drm_property_create_range(dev, 0, "zpos", min, max);
+	if (!prop)
+		return -ENOMEM;
+
+	dev->mode_config.zpos_property = prop;
+	return 0;
+}
+EXPORT_SYMBOL(drm_mode_create_zpos_property);
+
+/**
+ * drm_mode_create_zpos_immutable_property - create immuttable zpos property
+ * @dev: DRM device
+ * @min: minimal possible value of zpos property
+ * @max: maximal possible value of zpos property
+ *
+ * This function initializes generic immuttable zpos property and enables
+ * support for it in drm core. Using this property driver lets userspace
+ * to get the arrangement of the planes for blending operation and notifies
+ * it that the hardware (or driver) doesn't support changing of the planes'
+ * order.
+ *
+ * Returns:
+ * Zero on success, negative errno on failure.
+ */
+int drm_mode_create_zpos_immutable_property(struct drm_device *dev,
+					    unsigned int min, unsigned int max)
+{
+	struct drm_property *prop;
+
+	prop = drm_property_create_range(dev, DRM_MODE_PROP_IMMUTABLE, "zpos",
+					 min, max);
+	if (!prop)
+		return -ENOMEM;
+
+	dev->mode_config.zpos_immutable_property = prop;
+	return 0;
+}
+EXPORT_SYMBOL(drm_mode_create_zpos_immutable_property);
+
+static int drm_atomic_state_zpos_cmp(const void *a, const void *b)
+{
+	const struct drm_plane_state *sa = *(struct drm_plane_state **)a;
+	const struct drm_plane_state *sb = *(struct drm_plane_state **)b;
+	int zpos_a = (sa->zpos << 16) + sa->plane->base.id;
+	int zpos_b = (sb->zpos << 16) + sb->plane->base.id;
+
+	return zpos_a - zpos_b;
+}
+
+/**
+ * drm_atomic_helper_crtc_normalize_zpos - calculate normalized zpos values
+ * @crtc: crtc with planes, which have to be considered for normalization
+ * @crtc_state: new atomic state to apply
+ *
+ * This function checks new states of all planes assigned to given crtc and
+ * calculates normalized zpos value for them. Planes are compared first by their
+ * zpos values, then by plane id (if zpos equals). Plane with lowest zpos value
+ * is at the bottom. The plane_state->normalized_zpos is then filled with uniqe
+ * values from 0 to number of active planes in crtc minus one.
+ *
+ * RETURNS
+ * Zero for success or -errno
+ */
+int drm_atomic_helper_crtc_normalize_zpos(struct drm_crtc *crtc,
+					  struct drm_crtc_state *crtc_state)
+{
+	struct drm_atomic_state *state = crtc_state->state;
+	struct drm_device *dev = crtc->dev;
+	int total_planes = dev->mode_config.num_total_plane;
+	struct drm_plane_state **states;
+	struct drm_plane *plane;
+	int i, n = 0;
+	int ret = 0;
+
+	DRM_DEBUG_ATOMIC("[CRTC:%d:%s] calculating normalized zpos values\n",
+			 crtc->base.id, crtc->name);
+
+	states = kmalloc(total_planes * sizeof(*states), GFP_KERNEL);
+	if (!states)
+		return -ENOMEM;
+
+	/*
+	 * Normalization process might create new states for planes which
+	 * normalized_zpos has to be recalculated.
+	 */
+	drm_for_each_plane_mask(plane, dev, crtc_state->plane_mask) {
+		struct drm_plane_state *plane_state =
+			drm_atomic_get_plane_state(state, plane);
+		if (IS_ERR(plane_state)) {
+			ret = PTR_ERR(plane_state);
+			goto fail;
+		}
+		states[n++] = plane_state;
+		DRM_DEBUG_ATOMIC("[PLANE:%d:%s] processing zpos value %d\n",
+				 plane->base.id, plane->name, plane_state->zpos);
+	}
+
+	sort(states, n, sizeof(*states), drm_atomic_state_zpos_cmp, NULL);
+
+	for (i = 0; i < n; i++) {
+		plane = states[i]->plane;
+		states[i]->normalized_zpos = i;
+		DRM_DEBUG_ATOMIC("[PLANE:%d:%s] normalized zpos value %d\n",
+				 plane->base.id, plane->name, i);
+	}
+	crtc_state->zpos_changed = true;
+
+fail:
+	kfree(states);
+	return ret;
+}
+EXPORT_SYMBOL(drm_atomic_helper_crtc_normalize_zpos);
+
+/**
+ * drm_atomic_helper_normalize_zpos - calculate normalized zpos values for all
+ *				      crtcs
+ * @dev: DRM device
+ * @state: atomic state of DRM device
+ *
+ * This function calculates normalized zpos value for all modified planes in
+ * the provided atomic state of DRM device. For more information, see
+ * drm_atomic_helper_crtc_normalize_zpos() function.
+ *
+ * RETURNS
+ * Zero for success or -errno
+ */
+int drm_atomic_helper_normalize_zpos(struct drm_device *dev,
+				     struct drm_atomic_state *state)
+{
+	struct drm_crtc *crtc;
+	struct drm_crtc_state *crtc_state;
+	struct drm_plane *plane;
+	struct drm_plane_state *plane_state;
+	int i, ret = 0;
+
+	/*
+	 * If zpos_property is not initialized, then it makes no sense
+	 * to calculate normalized zpos values.
+	 */
+	if (!dev->mode_config.zpos_property)
+		return 0;
+
+	for_each_plane_in_state(state, plane, plane_state, i) {
+		crtc = plane_state->crtc;
+		if (!crtc)
+			continue;
+		if (plane->state->zpos != plane_state->zpos) {
+			crtc_state =
+				drm_atomic_get_existing_crtc_state(state, crtc);
+			crtc_state->zpos_changed = true;
+		}
+	}
+
+	for_each_crtc_in_state(state, crtc, crtc_state, i) {
+		if (crtc_state->plane_mask != crtc->state->plane_mask ||
+		    crtc_state->zpos_changed) {
+			ret = drm_atomic_helper_crtc_normalize_zpos(crtc,
+								    crtc_state);
+			if (ret)
+				return ret;
+		}
+	}
+	return 0;
+}
+EXPORT_SYMBOL(drm_atomic_helper_normalize_zpos);
diff --git a/drivers/gpu/drm/drm_crtc_internal.h b/drivers/gpu/drm/drm_crtc_internal.h
index 247dc8b62564..c87cd956b74b 100644
--- a/drivers/gpu/drm/drm_crtc_internal.h
+++ b/drivers/gpu/drm/drm_crtc_internal.h
@@ -42,3 +42,6 @@  int drm_atomic_get_property(struct drm_mode_object *obj,
 int drm_mode_atomic_ioctl(struct drm_device *dev,
 			  void *data, struct drm_file *file_priv);
 
+/* drm_blend.c */
+int drm_atomic_helper_normalize_zpos(struct drm_device *dev,
+				     struct drm_atomic_state *state);
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index c65a212db77e..4f32a358d631 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -305,6 +305,7 @@  struct drm_plane_helper_funcs;
  * @mode_changed: crtc_state->mode or crtc_state->enable has been changed
  * @active_changed: crtc_state->active has been toggled.
  * @connectors_changed: connectors to this crtc have been updated
+ * @zpos_changed: zpos values of planes on this crtc have been updated
  * @plane_mask: bitmask of (1 << drm_plane_index(plane)) of attached planes
  * @connector_mask: bitmask of (1 << drm_connector_index(connector)) of attached connectors
  * @last_vblank_count: for helpers and drivers to capture the vblank of the
@@ -332,6 +333,7 @@  struct drm_crtc_state {
 	bool mode_changed : 1;
 	bool active_changed : 1;
 	bool connectors_changed : 1;
+	bool zpos_changed : 1;
 
 	/* attached planes bitmask:
 	 * WARNING: transitional helpers do not maintain plane_mask so
@@ -1247,6 +1249,9 @@  struct drm_connector {
  *	plane (in 16.16)
  * @src_w: width of visible portion of plane (in 16.16)
  * @src_h: height of visible portion of plane (in 16.16)
+ * @zpos: priority of the given plane on crtc (optional)
+ * @normalized_zpos: normalized value of zpos: uniqe, range from 0 to
+ *	(number of planes - 1) for given crtc
  * @state: backpointer to global drm_atomic_state
  */
 struct drm_plane_state {
@@ -1267,6 +1272,10 @@  struct drm_plane_state {
 	/* Plane rotation */
 	unsigned int rotation;
 
+	/* Plane zpos */
+	unsigned int zpos;
+	unsigned int normalized_zpos;
+
 	struct drm_atomic_state *state;
 };
 
@@ -2087,6 +2096,8 @@  struct drm_mode_config {
 	struct drm_property *tile_property;
 	struct drm_property *plane_type_property;
 	struct drm_property *rotation_property;
+	struct drm_property *zpos_property;
+	struct drm_property *zpos_immutable_property;
 	struct drm_property *prop_src_x;
 	struct drm_property *prop_src_y;
 	struct drm_property *prop_src_w;
@@ -2488,6 +2499,12 @@  extern struct drm_property *drm_mode_create_rotation_property(struct drm_device
 extern unsigned int drm_rotation_simplify(unsigned int rotation,
 					  unsigned int supported_rotations);
 
+extern int drm_mode_create_zpos_property(struct drm_device *dev,
+					 unsigned int min, unsigned int max);
+extern int drm_mode_create_zpos_immutable_property(struct drm_device *dev,
+						   unsigned int min,
+						   unsigned int max);
+
 /* Helpers */
 
 static inline struct drm_plane *drm_plane_find(struct drm_device *dev,