drm/rcar-du: Introduce CRTCs groups

The R8A7779 DU is split in per-CRTC resources (scan-out engine, blending
unit, timings generator, ...) and device-global resources (start/stop
control, planes, ...) shared between the two CRTCs.

The R8A7790 introduced a third CRTC with its own set of global resources
This would be modeled as two separate DU device instances if it wasn't
for a handful or resources that are shared between the three CRTCs
(mostly related to input and output routing). For this reason the
R8A7790 DU must be modeled as a single device with three CRTCs, two sets
of "semi-global" resources, and a few device-global resources.

Introduce a new rcar_du_group driver-specific object, without any real
counterpart in the DU documentation, that models those semi-global
resources.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

10 files changed, 299 insertions, 203 deletions

diff --git a/drivers/gpu/drm/rcar-du/Makefile b/drivers/gpu/drm/rcar-du/Makefile
index 57b0fe1fa66..b9b5e666fbb 100644
--- a/drivers/gpu/drm/rcar-du/Makefile
+++ b/drivers/gpu/drm/rcar-du/Makefile
@@ -1,6 +1,7 @@
 rcar-du-drm-y := rcar_du_crtc.o \
 		 rcar_du_drv.o \
 		 rcar_du_encoder.o \
+		 rcar_du_group.o \
 		 rcar_du_kms.o \
 		 rcar_du_lvdscon.o \
 		 rcar_du_plane.o \
diff --git a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
index 03dd7018dde..7784a3ba785 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
+++ b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
@@ -30,21 +30,21 @@
 
 static u32 rcar_du_crtc_read(struct rcar_du_crtc *rcrtc, u32 reg)
 {
-	struct rcar_du_device *rcdu = rcrtc->crtc.dev->dev_private;
+	struct rcar_du_device *rcdu = rcrtc->group->dev;
 
 	return rcar_du_read(rcdu, rcrtc->mmio_offset + reg);
 }
 
 static void rcar_du_crtc_write(struct rcar_du_crtc *rcrtc, u32 reg, u32 data)
 {
-	struct rcar_du_device *rcdu = rcrtc->crtc.dev->dev_private;
+	struct rcar_du_device *rcdu = rcrtc->group->dev;
 
 	rcar_du_write(rcdu, rcrtc->mmio_offset + reg, data);
 }
 
 static void rcar_du_crtc_clr(struct rcar_du_crtc *rcrtc, u32 reg, u32 clr)
 {
-	struct rcar_du_device *rcdu = rcrtc->crtc.dev->dev_private;
+	struct rcar_du_device *rcdu = rcrtc->group->dev;
 
 	rcar_du_write(rcdu, rcrtc->mmio_offset + reg,
 		      rcar_du_read(rcdu, rcrtc->mmio_offset + reg) & ~clr);
@@ -52,7 +52,7 @@ static void rcar_du_crtc_clr(struct rcar_du_crtc *rcrtc, u32 reg, u32 clr)
 
 static void rcar_du_crtc_set(struct rcar_du_crtc *rcrtc, u32 reg, u32 set)
 {
-	struct rcar_du_device *rcdu = rcrtc->crtc.dev->dev_private;
+	struct rcar_du_device *rcdu = rcrtc->group->dev;
 
 	rcar_du_write(rcdu, rcrtc->mmio_offset + reg,
 		      rcar_du_read(rcdu, rcrtc->mmio_offset + reg) | set);
@@ -61,7 +61,7 @@ static void rcar_du_crtc_set(struct rcar_du_crtc *rcrtc, u32 reg, u32 set)
 static void rcar_du_crtc_clr_set(struct rcar_du_crtc *rcrtc, u32 reg,
 				 u32 clr, u32 set)
 {
-	struct rcar_du_device *rcdu = rcrtc->crtc.dev->dev_private;
+	struct rcar_du_device *rcdu = rcrtc->group->dev;
 	u32 value = rcar_du_read(rcdu, rcrtc->mmio_offset + reg);
 
 	rcar_du_write(rcdu, rcrtc->mmio_offset + reg, (value & ~clr) | set);
@@ -69,14 +69,13 @@ static void rcar_du_crtc_clr_set(struct rcar_du_crtc *rcrtc, u32 reg,
 
 static int rcar_du_crtc_get(struct rcar_du_crtc *rcrtc)
 {
-	struct rcar_du_device *rcdu = rcrtc->crtc.dev->dev_private;
 	int ret;
 
 	ret = clk_prepare_enable(rcrtc->clock);
 	if (ret < 0)
 		return ret;
 
-	ret = rcar_du_get(rcdu);
+	ret = rcar_du_group_get(rcrtc->group);
 	if (ret < 0)
 		clk_disable_unprepare(rcrtc->clock);
 
@@ -85,17 +84,14 @@ static int rcar_du_crtc_get(struct rcar_du_crtc *rcrtc)
 
 static void rcar_du_crtc_put(struct rcar_du_crtc *rcrtc)
 {
-	struct rcar_du_device *rcdu = rcrtc->crtc.dev->dev_private;
-
-	rcar_du_put(rcdu);
+	rcar_du_group_put(rcrtc->group);
 	clk_disable_unprepare(rcrtc->clock);
 }
 
 static void rcar_du_crtc_set_display_timing(struct rcar_du_crtc *rcrtc)
 {
-	struct drm_crtc *crtc = &rcrtc->crtc;
-	struct rcar_du_device *rcdu = crtc->dev->dev_private;
-	const struct drm_display_mode *mode = &crtc->mode;
+	const struct drm_display_mode *mode = &rcrtc->crtc.mode;
+	struct rcar_du_device *rcdu = rcrtc->group->dev;
 	unsigned long clk;
 	u32 value;
 	u32 div;
@@ -136,7 +132,7 @@ static void rcar_du_crtc_set_display_timing(struct rcar_du_crtc *rcrtc)
 
 static void rcar_du_crtc_set_routing(struct rcar_du_crtc *rcrtc)
 {
-	struct rcar_du_device *rcdu = rcrtc->crtc.dev->dev_private;
+	struct rcar_du_device *rcdu = rcrtc->group->dev;
 	u32 dorcr = rcar_du_read(rcdu, DORCR);
 
 	dorcr &= ~(DORCR_PG2T | DORCR_DK2S | DORCR_PG2D_MASK);
@@ -153,36 +149,6 @@ static void rcar_du_crtc_set_routing(struct rcar_du_crtc *rcrtc)
 	rcar_du_write(rcdu, DORCR, dorcr);
 }
 
-static void __rcar_du_start_stop(struct rcar_du_device *rcdu, bool start)
-{
-	rcar_du_write(rcdu, DSYSR,
-		      (rcar_du_read(rcdu, DSYSR) & ~(DSYSR_DRES | DSYSR_DEN)) |
-		      (start ? DSYSR_DEN : DSYSR_DRES));
-}
-
-static void rcar_du_start_stop(struct rcar_du_device *rcdu, bool start)
-{
-	/* Many of the configuration bits are only updated when the display
-	 * reset (DRES) bit in DSYSR is set to 1, disabling *both* CRTCs. Some
-	 * of those bits could be pre-configured, but others (especially the
-	 * bits related to plane assignment to display timing controllers) need
-	 * to be modified at runtime.
-	 *
-	 * Restart the display controller if a start is requested. Sorry for the
-	 * flicker. It should be possible to move most of the "DRES-update" bits
-	 * setup to driver initialization time and minimize the number of cases
-	 * when the display controller will have to be restarted.
-	 */
-	if (start) {
-		if (rcdu->used_crtcs++ != 0)
-			__rcar_du_start_stop(rcdu, false);
-		__rcar_du_start_stop(rcdu, true);
-	} else {
-		if (--rcdu->used_crtcs == 0)
-			__rcar_du_start_stop(rcdu, false);
-	}
-}
-
 void rcar_du_crtc_route_output(struct drm_crtc *crtc, unsigned int output)
 {
 	struct rcar_du_crtc *rcrtc = to_rcar_crtc(crtc);
@@ -195,8 +161,8 @@ void rcar_du_crtc_route_output(struct drm_crtc *crtc, unsigned int output)
 
 void rcar_du_crtc_update_planes(struct drm_crtc *crtc)
 {
-	struct rcar_du_device *rcdu = crtc->dev->dev_private;
 	struct rcar_du_crtc *rcrtc = to_rcar_crtc(crtc);
+	struct rcar_du_device *rcdu = rcrtc->group->dev;
 	struct rcar_du_plane *planes[RCAR_DU_NUM_HW_PLANES];
 	unsigned int num_planes = 0;
 	unsigned int prio = 0;
@@ -204,8 +170,8 @@ void rcar_du_crtc_update_planes(struct drm_crtc *crtc)
 	u32 dptsr = 0;
 	u32 dspr = 0;
 
-	for (i = 0; i < ARRAY_SIZE(rcdu->planes.planes); ++i) {
-		struct rcar_du_plane *plane = &rcdu->planes.planes[i];
+	for (i = 0; i < ARRAY_SIZE(rcrtc->group->planes.planes); ++i) {
+		struct rcar_du_plane *plane = &rcrtc->group->planes.planes[i];
 		unsigned int j;
 
 		if (plane->crtc != &rcrtc->crtc || !plane->enabled)
@@ -254,10 +220,8 @@ void rcar_du_crtc_update_planes(struct drm_crtc *crtc)
 		 */
 		if (value != dptsr) {
 			rcar_du_write(rcdu, DPTSR, dptsr);
-			if (rcdu->used_crtcs) {
-				__rcar_du_start_stop(rcdu, false);
-				__rcar_du_start_stop(rcdu, true);
-			}
+			if (rcrtc->group->used_crtcs)
+				rcar_du_group_restart(rcrtc->group);
 		}
 	}
 
@@ -267,7 +231,6 @@ void rcar_du_crtc_update_planes(struct drm_crtc *crtc)
 static void rcar_du_crtc_start(struct rcar_du_crtc *rcrtc)
 {
 	struct drm_crtc *crtc = &rcrtc->crtc;
-	struct rcar_du_device *rcdu = crtc->dev->dev_private;
 	unsigned int i;
 
 	if (rcrtc->started)
@@ -284,14 +247,14 @@ static void rcar_du_crtc_start(struct rcar_du_crtc *rcrtc)
 	rcar_du_crtc_set_display_timing(rcrtc);
 	rcar_du_crtc_set_routing(rcrtc);
 
-	mutex_lock(&rcdu->planes.lock);
+	mutex_lock(&rcrtc->group->planes.lock);
 	rcrtc->plane->enabled = true;
 	rcar_du_crtc_update_planes(crtc);
-	mutex_unlock(&rcdu->planes.lock);
+	mutex_unlock(&rcrtc->group->planes.lock);
 
 	/* Setup planes. */
-	for (i = 0; i < ARRAY_SIZE(rcdu->planes.planes); ++i) {
-		struct rcar_du_plane *plane = &rcdu->planes.planes[i];
+	for (i = 0; i < ARRAY_SIZE(rcrtc->group->planes.planes); ++i) {
+		struct rcar_du_plane *plane = &rcrtc->group->planes.planes[i];
 
 		if (plane->crtc != crtc || !plane->enabled)
 			continue;
@@ -305,7 +268,7 @@ static void rcar_du_crtc_start(struct rcar_du_crtc *rcrtc)
 	 */
 	rcar_du_crtc_clr_set(rcrtc, DSYSR, DSYSR_TVM_MASK, DSYSR_TVM_MASTER);
 
-	rcar_du_start_stop(rcdu, true);
+	rcar_du_group_start_stop(rcrtc->group, true);
 
 	rcrtc->started = true;
 }
@@ -313,22 +276,21 @@ static void rcar_du_crtc_start(struct rcar_du_crtc *rcrtc)
 static void rcar_du_crtc_stop(struct rcar_du_crtc *rcrtc)
 {
 	struct drm_crtc *crtc = &rcrtc->crtc;
-	struct rcar_du_device *rcdu = crtc->dev->dev_private;
 
 	if (!rcrtc->started)
 		return;
 
-	mutex_lock(&rcdu->planes.lock);
+	mutex_lock(&rcrtc->group->planes.lock);
 	rcrtc->plane->enabled = false;
 	rcar_du_crtc_update_planes(crtc);
-	mutex_unlock(&rcdu->planes.lock);
+	mutex_unlock(&rcrtc->group->planes.lock);
 
 	/* Select switch sync mode. This stops display operation and configures
 	 * the HSYNC and VSYNC signals as inputs.
 	 */
 	rcar_du_crtc_clr_set(rcrtc, DSYSR, DSYSR_TVM_MASK, DSYSR_TVM_SWITCH);
 
-	rcar_du_start_stop(rcdu, false);
+	rcar_du_group_start_stop(rcrtc->group, false);
 
 	rcrtc->started = false;
 }
@@ -406,8 +368,8 @@ static int rcar_du_crtc_mode_set(struct drm_crtc *crtc,
 				 int x, int y,
 				 struct drm_framebuffer *old_fb)
 {
-	struct rcar_du_device *rcdu = crtc->dev->dev_private;
 	struct rcar_du_crtc *rcrtc = to_rcar_crtc(crtc);
+	struct rcar_du_device *rcdu = rcrtc->group->dev;
 	const struct rcar_du_format_info *format;
 	int ret;
 
@@ -583,8 +545,9 @@ static const struct drm_crtc_funcs crtc_funcs = {
 	.page_flip = rcar_du_crtc_page_flip,
 };
 
-int rcar_du_crtc_create(struct rcar_du_device *rcdu, unsigned int index)
+int rcar_du_crtc_create(struct rcar_du_group *rgrp, unsigned int index)
 {
+	struct rcar_du_device *rcdu = rgrp->dev;
 	struct platform_device *pdev = to_platform_device(rcdu->dev);
 	struct rcar_du_crtc *rcrtc = &rcdu->crtcs[index];
 	struct drm_crtc *crtc = &rcrtc->crtc;
@@ -608,10 +571,11 @@ int rcar_du_crtc_create(struct rcar_du_device *rcdu, unsigned int index)
 		return PTR_ERR(rcrtc->clock);
 	}
 
+	rcrtc->group = rgrp;
 	rcrtc->mmio_offset = index ? DISP2_REG_OFFSET : 0;
 	rcrtc->index = index;
 	rcrtc->dpms = DRM_MODE_DPMS_OFF;
-	rcrtc->plane = &rcdu->planes.planes[index];
+	rcrtc->plane = &rgrp->planes.planes[index];
 
 	rcrtc->plane->crtc = crtc;
 
diff --git a/drivers/gpu/drm/rcar-du/rcar_du_crtc.h b/drivers/gpu/drm/rcar-du/rcar_du_crtc.h
index 5b69e98a3b9..542a7feceb2 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_crtc.h
+++ b/drivers/gpu/drm/rcar-du/rcar_du_crtc.h
@@ -19,7 +19,7 @@
 #include <drm/drmP.h>
 #include <drm/drm_crtc.h>
 
-struct rcar_du_device;
+struct rcar_du_group;
 struct rcar_du_plane;
 
 struct rcar_du_crtc {
@@ -34,10 +34,11 @@ struct rcar_du_crtc {
 	unsigned int outputs;
 	int dpms;
 
+	struct rcar_du_group *group;
 	struct rcar_du_plane *plane;
 };
 
-int rcar_du_crtc_create(struct rcar_du_device *rcdu, unsigned int index);
+int rcar_du_crtc_create(struct rcar_du_group *rgrp, unsigned int index);
 void rcar_du_crtc_enable_vblank(struct rcar_du_crtc *rcrtc, bool enable);
 void rcar_du_crtc_cancel_page_flip(struct rcar_du_crtc *rcrtc,
 				   struct drm_file *file);
diff --git a/drivers/gpu/drm/rcar-du/rcar_du_drv.c b/drivers/gpu/drm/rcar-du/rcar_du_drv.c
index 5f82e046f83..cdc363b6cd3 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_drv.c
+++ b/drivers/gpu/drm/rcar-du/rcar_du_drv.c
@@ -29,52 +29,6 @@
 #include "rcar_du_regs.h"
 
 /* -----------------------------------------------------------------------------
- * Core device operations
- */
-
-/*
- * rcar_du_get - Acquire a reference to the DU
- *
- * Acquiring the first  reference setups core registers. A reference must be
- * held before accessing any hardware registers.
- *
- * This function must be called with the DRM mode_config lock held.
- *
- * Return 0 in case of success or a negative error code otherwise.
- */
-int rcar_du_get(struct rcar_du_device *rcdu)
-{
-	if (rcdu->use_count)
-		goto done;
-
-	/* Enable extended features */
-	rcar_du_write(rcdu, DEFR, DEFR_CODE | DEFR_DEFE);
-	rcar_du_write(rcdu, DEFR2, DEFR2_CODE | DEFR2_DEFE2G);
-	rcar_du_write(rcdu, DEFR3, DEFR3_CODE | DEFR3_DEFE3);
-	rcar_du_write(rcdu, DEFR4, DEFR4_CODE);
-	rcar_du_write(rcdu, DEFR5, DEFR5_CODE | DEFR5_DEFE5);
-
-	/* Use DS1PR and DS2PR to configure planes priorities and connects the
-	 * superposition 0 to DU0 pins. DU1 pins will be configured dynamically.
-	 */
-	rcar_du_write(rcdu, DORCR, DORCR_PG1D_DS1 | DORCR_DPRS);
-
-done:
-	rcdu->use_count++;
-	return 0;
-}
-
-/*
- * rcar_du_put - Release a reference to the DU
- *
- * This function must be called with the DRM mode_config lock held.
- */
-void rcar_du_put(struct rcar_du_device *rcdu)
-{
-	--rcdu->use_count;
-}
-
-/* -----------------------------------------------------------------------------
  * DRM operations
  */
 
diff --git a/drivers/gpu/drm/rcar-du/rcar_du_drv.h b/drivers/gpu/drm/rcar-du/rcar_du_drv.h
index 0305c21d71f..5b57a2f9b52 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_drv.h
+++ b/drivers/gpu/drm/rcar-du/rcar_du_drv.h
@@ -18,11 +18,12 @@
 #include <linux/platform_data/rcar-du.h>
 
 #include "rcar_du_crtc.h"
-#include "rcar_du_plane.h"
+#include "rcar_du_group.h"
 
 struct clk;
 struct device;
 struct drm_device;
+struct rcar_du_device;
 
 #define RCAR_DU_FEATURE_CRTC_IRQ_CLOCK	(1 << 0)	/* Per-CRTC IRQ and clock */
 
@@ -40,15 +41,13 @@ struct rcar_du_device {
 	const struct rcar_du_device_info *info;
 
 	void __iomem *mmio;
-	unsigned int use_count;
 
 	struct drm_device *ddev;
 
 	struct rcar_du_crtc crtcs[2];
-	unsigned int used_crtcs;
 	unsigned int num_crtcs;
 
-	struct rcar_du_planes planes;
+	struct rcar_du_group group;
 };
 
 static inline bool rcar_du_has(struct rcar_du_device *rcdu,
@@ -57,9 +56,6 @@ static inline bool rcar_du_has(struct rcar_du_device *rcdu,
 	return rcdu->info->features & feature;
 }
 
-int rcar_du_get(struct rcar_du_device *rcdu);
-void rcar_du_put(struct rcar_du_device *rcdu);
-
 static inline u32 rcar_du_read(struct rcar_du_device *rcdu, u32 reg)
 {
 	return ioread32(rcdu->mmio + reg);
diff --git a/drivers/gpu/drm/rcar-du/rcar_du_group.c b/drivers/gpu/drm/rcar-du/rcar_du_group.c
new file mode 100644
index 00000000000..625b9f44696
--- /dev/null
+++ b/drivers/gpu/drm/rcar-du/rcar_du_group.c
@@ -0,0 +1,127 @@
+/*
+ * rcar_du_group.c  --  R-Car Display Unit Channels Pair
+ *
+ * Copyright (C) 2013 Renesas Corporation
+ *
+ * Contact: Laurent Pinchart (laurent.pinchart@ideasonboard.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+/*
+ * The R8A7779 DU is split in per-CRTC resources (scan-out engine, blending
+ * unit, timings generator, ...) and device-global resources (start/stop
+ * control, planes, ...) shared between the two CRTCs.
+ *
+ * The R8A7790 introduced a third CRTC with its own set of global resources.
+ * This would be modeled as two separate DU device instances if it wasn't for
+ * a handful or resources that are shared between the three CRTCs (mostly
+ * related to input and output routing). For this reason the R8A7790 DU must be
+ * modeled as a single device with three CRTCs, two sets of "semi-global"
+ * resources, and a few device-global resources.
+ *
+ * The rcar_du_group object is a driver specific object, without any real
+ * counterpart in the DU documentation, that models those semi-global resources.
+ */
+
+#include <linux/io.h>
+
+#include "rcar_du_drv.h"
+#include "rcar_du_group.h"
+#include "rcar_du_regs.h"
+
+static u32 rcar_du_group_read(struct rcar_du_group *rgrp, u32 reg)
+{
+	return rcar_du_read(rgrp->dev, rgrp->mmio_offset + reg);
+}
+
+static void rcar_du_group_write(struct rcar_du_group *rgrp, u32 reg, u32 data)
+{
+	rcar_du_write(rgrp->dev, rgrp->mmio_offset + reg, data);
+}
+
+static void rcar_du_group_setup(struct rcar_du_group *rgrp)
+{
+	/* Enable extended features */
+	rcar_du_group_write(rgrp, DEFR, DEFR_CODE | DEFR_DEFE);
+	rcar_du_group_write(rgrp, DEFR2, DEFR2_CODE | DEFR2_DEFE2G);
+	rcar_du_group_write(rgrp, DEFR3, DEFR3_CODE | DEFR3_DEFE3);
+	rcar_du_group_write(rgrp, DEFR4, DEFR4_CODE);
+	rcar_du_group_write(rgrp, DEFR5, DEFR5_CODE | DEFR5_DEFE5);
+
+	/* Use DS1PR and DS2PR to configure planes priorities and connects the
+	 * superposition 0 to DU0 pins. DU1 pins will be configured dynamically.
+	 */
+	rcar_du_group_write(rgrp, DORCR, DORCR_PG1D_DS1 | DORCR_DPRS);
+}
+
+/*
+ * rcar_du_group_get - Acquire a reference to the DU channels group
+ *
+ * Acquiring the first reference setups core registers. A reference must be held
+ * before accessing any hardware registers.
+ *
+ * This function must be called with the DRM mode_config lock held.
+ *
+ * Return 0 in case of success or a negative error code otherwise.
+ */
+int rcar_du_group_get(struct rcar_du_group *rgrp)
+{
+	if (rgrp->use_count)
+		goto done;
+
+	rcar_du_group_setup(rgrp);
+
+done:
+	rgrp->use_count++;
+	return 0;
+}
+
+/*
+ * rcar_du_group_put - Release a reference to the DU
+ *
+ * This function must be called with the DRM mode_config lock held.
+ */
+void rcar_du_group_put(struct rcar_du_group *rgrp)
+{
+	--rgrp->use_count;
+}
+
+static void __rcar_du_group_start_stop(struct rcar_du_group *rgrp, bool start)
+{
+	rcar_du_group_write(rgrp, DSYSR,
+		(rcar_du_group_read(rgrp, DSYSR) & ~(DSYSR_DRES | DSYSR_DEN)) |
+		(start ? DSYSR_DEN : DSYSR_DRES));
+}
+
+void rcar_du_group_start_stop(struct rcar_du_group *rgrp, bool start)
+{
+	/* Many of the configuration bits are only updated when the display
+	 * reset (DRES) bit in DSYSR is set to 1, disabling *both* CRTCs. Some
+	 * of those bits could be pre-configured, but others (especially the
+	 * bits related to plane assignment to display timing controllers) need
+	 * to be modified at runtime.
+	 *
+	 * Restart the display controller if a start is requested. Sorry for the
+	 * flicker. It should be possible to move most of the "DRES-update" bits
+	 * setup to driver initialization time and minimize the number of cases
+	 * when the display controller will have to be restarted.
+	 */
+	if (start) {
+		if (rgrp->used_crtcs++ != 0)
+			__rcar_du_group_start_stop(rgrp, false);
+		__rcar_du_group_start_stop(rgrp, true);
+	} else {
+		if (--rgrp->used_crtcs == 0)
+			__rcar_du_group_start_stop(rgrp, false);
+	}
+}
+
+void rcar_du_group_restart(struct rcar_du_group *rgrp)
+{
+	__rcar_du_group_start_stop(rgrp, false);
+	__rcar_du_group_start_stop(rgrp, true);
+}
diff --git a/drivers/gpu/drm/rcar-du/rcar_du_group.h b/drivers/gpu/drm/rcar-du/rcar_du_group.h
new file mode 100644
index 00000000000..748331bbb8f
--- /dev/null
+++ b/drivers/gpu/drm/rcar-du/rcar_du_group.h
@@ -0,0 +1,47 @@
+/*
+ * rcar_du_group.c  --  R-Car Display Unit Planes and CRTCs Group
+ *
+ * Copyright (C) 2013 Renesas Corporation
+ *
+ * Contact: Laurent Pinchart (laurent.pinchart@ideasonboard.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#ifndef __RCAR_DU_GROUP_H__
+#define __RCAR_DU_GROUP_H__
+
+#include "rcar_du_plane.h"
+
+struct rcar_du_device;
+
+/*
+ * struct rcar_du_group - CRTCs and planes group
+ * @dev: the DU device
+ * @mmio_offset: registers offset in the device memory map
+ * @index: group index
+ * @use_count: number of users of the group (rcar_du_group_(get|put))
+ * @used_crtcs: number of CRTCs currently in use
+ * @planes: planes handled by the group
+ */
+struct rcar_du_group {
+	struct rcar_du_device *dev;
+	unsigned int mmio_offset;
+	unsigned int index;
+
+	unsigned int use_count;
+	unsigned int used_crtcs;
+
+	struct rcar_du_planes planes;
+};
+
+int rcar_du_group_get(struct rcar_du_group *rgrp);
+void rcar_du_group_put(struct rcar_du_group *rgrp);
+void rcar_du_group_start_stop(struct rcar_du_group *rgrp, bool start);
+void rcar_du_group_restart(struct rcar_du_group *rgrp);
+
+
+#endif /* __RCAR_DU_GROUP_H__ */
diff --git a/drivers/gpu/drm/rcar-du/rcar_du_kms.c b/drivers/gpu/drm/rcar-du/rcar_du_kms.c
index a1343fbde57..c32e0f9d482 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_kms.c
+++ b/drivers/gpu/drm/rcar-du/rcar_du_kms.c
@@ -174,17 +174,20 @@ int rcar_du_modeset_init(struct rcar_du_device *rcdu)
 	rcdu->ddev->mode_config.max_height = 2047;
 	rcdu->ddev->mode_config.funcs = &rcar_du_mode_config_funcs;
 
-	ret = rcar_du_planes_init(rcdu);
+	rcdu->group.dev = rcdu;
+	rcdu->group.index = 0;
+	rcdu->group.used_crtcs = 0;
+
+	ret = rcar_du_planes_init(&rcdu->group);
 	if (ret < 0)
 		return ret;
 
 	for (i = 0; i < ARRAY_SIZE(rcdu->crtcs); ++i) {
-		ret = rcar_du_crtc_create(rcdu, i);
+		ret = rcar_du_crtc_create(&rcdu->group, i);
 		if (ret < 0)
 			return ret;
 	}
 
-	rcdu->used_crtcs = 0;
 	rcdu->num_crtcs = i;
 
 	for (i = 0; i < rcdu->pdata->num_encoders; ++i) {
@@ -215,7 +218,7 @@ int rcar_du_modeset_init(struct rcar_du_device *rcdu)
 		encoder->possible_clones = 1 << 0;
 	}
 
-	ret = rcar_du_planes_register(rcdu);
+	ret = rcar_du_planes_register(&rcdu->group);
 	if (ret < 0)
 		return ret;
 
diff --git a/drivers/gpu/drm/rcar-du/rcar_du_plane.c b/drivers/gpu/drm/rcar-du/rcar_du_plane.c
index 29f21477ef0..1e9cf7c92f8 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_plane.c
+++ b/drivers/gpu/drm/rcar-du/rcar_du_plane.c
@@ -36,71 +36,73 @@ static inline struct rcar_du_plane *to_rcar_plane(struct drm_plane *plane)
 	return container_of(plane, struct rcar_du_kms_plane, plane)->hwplane;
 }
 
-static u32 rcar_du_plane_read(struct rcar_du_device *rcdu,
+static u32 rcar_du_plane_read(struct rcar_du_group *rgrp,
 			      unsigned int index, u32 reg)
 {
-	return rcar_du_read(rcdu, index * PLANE_OFF + reg);
+	return rcar_du_read(rgrp->dev,
+			    rgrp->mmio_offset + index * PLANE_OFF + reg);
 }
 
-static void rcar_du_plane_write(struct rcar_du_device *rcdu,
+static void rcar_du_plane_write(struct rcar_du_group *rgrp,
 				unsigned int index, u32 reg, u32 data)
 {
-	rcar_du_write(rcdu, index * PLANE_OFF + reg, data);
+	rcar_du_write(rgrp->dev, rgrp->mmio_offset + index * PLANE_OFF + reg,
+		      data);
 }
 
 int rcar_du_plane_reserve(struct rcar_du_plane *plane,
 			  const struct rcar_du_format_info *format)
 {
-	struct rcar_du_device *rcdu = plane->dev;
+	struct rcar_du_group *rgrp = plane->group;
 	unsigned int i;
 	int ret = -EBUSY;
 
-	mutex_lock(&rcdu->planes.lock);
+	mutex_lock(&rgrp->planes.lock);
 
-	for (i = 0; i < ARRAY_SIZE(rcdu->planes.planes); ++i) {
-		if (!(rcdu->planes.free & (1 << i)))
+	for (i = 0; i < ARRAY_SIZE(rgrp->planes.planes); ++i) {
+		if (!(rgrp->planes.free & (1 << i)))
 			continue;
 
 		if (format->planes == 1 ||
-		    rcdu->planes.free & (1 << ((i + 1) % 8)))
+		    rgrp->planes.free & (1 << ((i + 1) % 8)))
 			break;
 	}
 
-	if (i == ARRAY_SIZE(rcdu->planes.planes))
+	if (i == ARRAY_SIZE(rgrp->planes.planes))
 		goto done;
 
-	rcdu->planes.free &= ~(1 << i);
+	rgrp->planes.free &= ~(1 << i);
 	if (format->planes == 2)
-		rcdu->planes.free &= ~(1 << ((i + 1) % 8));
+		rgrp->planes.free &= ~(1 << ((i + 1) % 8));
 
 	plane->hwindex = i;
 
 	ret = 0;
 
 done:
-	mutex_unlock(&rcdu->planes.lock);
+	mutex_unlock(&rgrp->planes.lock);
 	return ret;
 }
 
 void rcar_du_plane_release(struct rcar_du_plane *plane)
 {
-	struct rcar_du_device *rcdu = plane->dev;
+	struct rcar_du_group *rgrp = plane->group;
 
 	if (plane->hwindex == -1)
 		return;
 
-	mutex_lock(&rcdu->planes.lock);
-	rcdu->planes.free |= 1 << plane->hwindex;
+	mutex_lock(&rgrp->planes.lock);
+	rgrp->planes.free |= 1 << plane->hwindex;
 	if (plane->format->planes == 2)
-		rcdu->planes.free |= 1 << ((plane->hwindex + 1) % 8);
-	mutex_unlock(&rcdu->planes.lock);
+		rgrp->planes.free |= 1 << ((plane->hwindex + 1) % 8);
+	mutex_unlock(&rgrp->planes.lock);
 
 	plane->hwindex = -1;
 }
 
 void rcar_du_plane_update_base(struct rcar_du_plane *plane)
 {
-	struct rcar_du_device *rcdu = plane->dev;
+	struct rcar_du_group *rgrp = plane->group;
 	unsigned int index = plane->hwindex;
 
 	/* The Y position is expressed in raster line units and must be doubled
@@ -111,18 +113,18 @@ void rcar_du_plane_update_base(struct rcar_du_plane *plane)
 	 * Similarly, for the second plane, NV12 and NV21 formats seem to
 	 * require a halved Y position value.
 	 */
-	rcar_du_plane_write(rcdu, index, PnSPXR, plane->src_x);
-	rcar_du_plane_write(rcdu, index, PnSPYR, plane->src_y *
+	rcar_du_plane_write(rgrp, index, PnSPXR, plane->src_x);
+	rcar_du_plane_write(rgrp, index, PnSPYR, plane->src_y *
 			    (plane->format->bpp == 32 ? 2 : 1));
-	rcar_du_plane_write(rcdu, index, PnDSA0R, plane->dma[0]);
+	rcar_du_plane_write(rgrp, index, PnDSA0R, plane->dma[0]);
 
 	if (plane->format->planes == 2) {
 		index = (index + 1) % 8;
 
-		rcar_du_plane_write(rcdu, index, PnSPXR, plane->src_x);
-		rcar_du_plane_write(rcdu, index, PnSPYR, plane->src_y *
+		rcar_du_plane_write(rgrp, index, PnSPXR, plane->src_x);
+		rcar_du_plane_write(rgrp, index, PnSPYR, plane->src_y *
 				    (plane->format->bpp == 16 ? 2 : 1) / 2);
-		rcar_du_plane_write(rcdu, index, PnDSA0R, plane->dma[1]);
+		rcar_du_plane_write(rgrp, index, PnDSA0R, plane->dma[1]);
 	}
 }
 
@@ -143,7 +145,7 @@ void rcar_du_plane_compute_base(struct rcar_du_plane *plane,
 static void rcar_du_plane_setup_mode(struct rcar_du_plane *plane,
 				     unsigned int index)
 {
-	struct rcar_du_device *rcdu = plane->dev;
+	struct rcar_du_group *rgrp = plane->group;
 	u32 colorkey;
 	u32 pnmr;
 
@@ -157,9 +159,9 @@ static void rcar_du_plane_setup_mode(struct rcar_du_plane *plane,
 	 * enable alpha-blending regardless of the X bit value.
 	 */
 	if (plane->format->fourcc != DRM_FORMAT_XRGB1555)
-		rcar_du_plane_write(rcdu, index, PnALPHAR, PnALPHAR_ABIT_0);
+		rcar_du_plane_write(rgrp, index, PnALPHAR, PnALPHAR_ABIT_0);
 	else
-		rcar_du_plane_write(rcdu, index, PnALPHAR,
+		rcar_du_plane_write(rgrp, index, PnALPHAR,
 				    PnALPHAR_ABIT_X | plane->alpha);
 
 	pnmr = PnMR_BM_MD | plane->format->pnmr;
@@ -175,14 +177,14 @@ static void rcar_du_plane_setup_mode(struct rcar_du_plane *plane,
 	if (plane->format->fourcc == DRM_FORMAT_YUYV)
 		pnmr |= PnMR_YCDF_YUYV;
 
-	rcar_du_plane_write(rcdu, index, PnMR, pnmr);
+	rcar_du_plane_write(rgrp, index, PnMR, pnmr);
 
 	switch (plane->format->fourcc) {
 	case DRM_FORMAT_RGB565:
 		colorkey = ((plane->colorkey & 0xf80000) >> 8)
 			 | ((plane->colorkey & 0x00fc00) >> 5)
 			 | ((plane->colorkey & 0x0000f8) >> 3);
-		rcar_du_plane_write(rcdu, index, PnTC2R, colorkey);
+		rcar_du_plane_write(rgrp, index, PnTC2R, colorkey);
 		break;
 
 	case DRM_FORMAT_ARGB1555:
@@ -190,12 +192,12 @@ static void rcar_du_plane_setup_mode(struct rcar_du_plane *plane,
 		colorkey = ((plane->colorkey & 0xf80000) >> 9)
 			 | ((plane->colorkey & 0x00f800) >> 6)
 			 | ((plane->colorkey & 0x0000f8) >> 3);
-		rcar_du_plane_write(rcdu, index, PnTC2R, colorkey);
+		rcar_du_plane_write(rgrp, index, PnTC2R, colorkey);
 		break;
 
 	case DRM_FORMAT_XRGB8888:
 	case DRM_FORMAT_ARGB8888:
-		rcar_du_plane_write(rcdu, index, PnTC3R,
+		rcar_du_plane_write(rgrp, index, PnTC3R,
 				    PnTC3R_CODE | (plane->colorkey & 0xffffff));
 		break;
 	}
@@ -204,7 +206,7 @@ static void rcar_du_plane_setup_mode(struct rcar_du_plane *plane,
 static void __rcar_du_plane_setup(struct rcar_du_plane *plane,
 				  unsigned int index)
 {
-	struct rcar_du_device *rcdu = plane->dev;
+	struct rcar_du_group *rgrp = plane->group;
 	u32 ddcr2 = PnDDCR2_CODE;
 	u32 ddcr4;
 	u32 mwr;
@@ -214,7 +216,7 @@ static void __rcar_du_plane_setup(struct rcar_du_plane *plane,
 	 * The data format is selected by the DDDF field in PnMR and the EDF
 	 * field in DDCR4.
 	 */
-	ddcr4 = rcar_du_plane_read(rcdu, index, PnDDCR4);
+	ddcr4 = rcar_du_plane_read(rgrp, index, PnDDCR4);
 	ddcr4 &= ~PnDDCR4_EDF_MASK;
 	ddcr4 |= plane->format->edf | PnDDCR4_CODE;
 
@@ -235,8 +237,8 @@ static void __rcar_du_plane_setup(struct rcar_du_plane *plane,
 		}
 	}
 
-	rcar_du_plane_write(rcdu, index, PnDDCR2, ddcr2);
-	rcar_du_plane_write(rcdu, index, PnDDCR4, ddcr4);
+	rcar_du_plane_write(rgrp, index, PnDDCR2, ddcr2);
+	rcar_du_plane_write(rgrp, index, PnDDCR4, ddcr4);
 
 	/* Memory pitch (expressed in pixels) */
 	if (plane->format->planes == 2)
@@ -244,19 +246,19 @@ static void __rcar_du_plane_setup(struct rcar_du_plane *plane,
 	else
 		mwr = plane->pitch * 8 / plane->format->bpp;
 
-	rcar_du_plane_write(rcdu, index, PnMWR, mwr);
+	rcar_du_plane_write(rgrp, index, PnMWR, mwr);
 
 	/* Destination position and size */
-	rcar_du_plane_write(rcdu, index, PnDSXR, plane->width);
-	rcar_du_plane_write(rcdu, index, PnDSYR, plane->height);
-	rcar_du_plane_write(rcdu, index, PnDPXR, plane->dst_x);
-	rcar_du_plane_write(rcdu, index, PnDPYR, plane->dst_y);
+	rcar_du_plane_write(rgrp, index, PnDSXR, plane->width);
+	rcar_du_plane_write(rgrp, index, PnDSYR, plane->height);
+	rcar_du_plane_write(rgrp, index, PnDPXR, plane->dst_x);
+	rcar_du_plane_write(rgrp, index, PnDPYR, plane->dst_y);
 
 	/* Wrap-around and blinking, disabled */
-	rcar_du_plane_write(rcdu, index, PnWASPR, 0);
-	rcar_du_plane_write(rcdu, index, PnWAMWR, 4095);
-	rcar_du_plane_write(rcdu, index, PnBTR, 0);
-	rcar_du_plane_write(rcdu, index, PnMLR, 0);
+	rcar_du_plane_write(rgrp, index, PnWASPR, 0);
+	rcar_du_plane_write(rgrp, index, PnWAMWR, 4095);
+	rcar_du_plane_write(rgrp, index, PnBTR, 0);
+	rcar_du_plane_write(rgrp, index, PnMLR, 0);
 }
 
 void rcar_du_plane_setup(struct rcar_du_plane *plane)
@@ -276,7 +278,7 @@ rcar_du_plane_update(struct drm_plane *plane, struct drm_crtc *crtc,
 		       uint32_t src_w, uint32_t src_h)
 {
 	struct rcar_du_plane *rplane = to_rcar_plane(plane);
-	struct rcar_du_device *rcdu = plane->dev->dev_private;
+	struct rcar_du_device *rcdu = rplane->group->dev;
 	const struct rcar_du_format_info *format;
 	unsigned int nplanes;
 	int ret;
@@ -319,26 +321,25 @@ rcar_du_plane_update(struct drm_plane *plane, struct drm_crtc *crtc,
 	rcar_du_plane_compute_base(rplane, fb);
 	rcar_du_plane_setup(rplane);
 
-	mutex_lock(&rcdu->planes.lock);
+	mutex_lock(&rplane->group->planes.lock);
 	rplane->enabled = true;
 	rcar_du_crtc_update_planes(rplane->crtc);
-	mutex_unlock(&rcdu->planes.lock);
+	mutex_unlock(&rplane->group->planes.lock);
 
 	return 0;
 }
 
 static int rcar_du_plane_disable(struct drm_plane *plane)
 {
-	struct rcar_du_device *rcdu = plane->dev->dev_private;
 	struct rcar_du_plane *rplane = to_rcar_plane(plane);
 
 	if (!rplane->enabled)
 		return 0;
 
-	mutex_lock(&rcdu->planes.lock);
+	mutex_lock(&rplane->group->planes.lock);
 	rplane->enabled = false;
 	rcar_du_crtc_update_planes(rplane->crtc);
-	mutex_unlock(&rcdu->planes.lock);
+	mutex_unlock(&rplane->group->planes.lock);
 
 	rcar_du_plane_release(rplane);
 
@@ -380,9 +381,7 @@ static void rcar_du_plane_set_colorkey(struct rcar_du_plane *plane,
 static void rcar_du_plane_set_zpos(struct rcar_du_plane *plane,
 				   unsigned int zpos)
 {
-	struct rcar_du_device *rcdu = plane->dev;
-
-	mutex_lock(&rcdu->planes.lock);
+	mutex_lock(&plane->group->planes.lock);
 	if (plane->zpos == zpos)
 		goto done;
 
@@ -393,21 +392,21 @@ static void rcar_du_plane_set_zpos(struct rcar_du_plane *plane,
 	rcar_du_crtc_update_planes(plane->crtc);
 
 done:
-	mutex_unlock(&rcdu->planes.lock);
+	mutex_unlock(&plane->group->planes.lock);
 }
 
 static int rcar_du_plane_set_property(struct drm_plane *plane,
 				      struct drm_property *property,
 				      uint64_t value)
 {
-	struct rcar_du_device *rcdu = plane->dev->dev_private;
 	struct rcar_du_plane *rplane = to_rcar_plane(plane);
+	struct rcar_du_group *rgrp = rplane->group;
 
-	if (property == rcdu->planes.alpha)
+	if (property == rgrp->planes.alpha)
 		rcar_du_plane_set_alpha(rplane, value);
-	else if (property == rcdu->planes.colorkey)
+	else if (property == rgrp->planes.colorkey)
 		rcar_du_plane_set_colorkey(rplane, value);
-	else if (property == rcdu->planes.zpos)
+	else if (property == rgrp->planes.zpos)
 		rcar_du_plane_set_zpos(rplane, value);
 	else
 		return -EINVAL;
@@ -435,37 +434,39 @@ static const uint32_t formats[] = {
 	DRM_FORMAT_NV16,
 };
 
-int rcar_du_planes_init(struct rcar_du_device *rcdu)
+int rcar_du_planes_init(struct rcar_du_group *rgrp)
 {
+	struct rcar_du_planes *planes = &rgrp->planes;
+	struct rcar_du_device *rcdu = rgrp->dev;
 	unsigned int i;
 
-	mutex_init(&rcdu->planes.lock);
-	rcdu->planes.free = 0xff;
+	mutex_init(&planes->lock);
+	planes->free = 0xff;
 
-	rcdu->planes.alpha =
+	planes->alpha =
 		drm_property_create_range(rcdu->ddev, 0, "alpha", 0, 255);
-	if (rcdu->planes.alpha == NULL)
+	if (planes->alpha == NULL)
 		return -ENOMEM;
 
 	/* The color key is expressed as an RGB888 triplet stored in a 32-bit
 	 * integer in XRGB8888 format. Bit 24 is used as a flag to disable (0)
 	 * or enable source color keying (1).
 	 */
-	rcdu->planes.colorkey =
+	planes->colorkey =
 		drm_property_create_range(rcdu->ddev, 0, "colorkey",
 					  0, 0x01ffffff);
-	if (rcdu->planes.colorkey == NULL)
+	if (planes->colorkey == NULL)
 		return -ENOMEM;
 
-	rcdu->planes.zpos =
+	planes->zpos =
 		drm_property_create_range(rcdu->ddev, 0, "zpos", 1, 7);
-	if (rcdu->planes.zpos == NULL)
+	if (planes->zpos == NULL)
 		return -ENOMEM;
 
-	for (i = 0; i < ARRAY_SIZE(rcdu->planes.planes); ++i) {
-		struct rcar_du_plane *plane = &rcdu->planes.planes[i];
+	for (i = 0; i < ARRAY_SIZE(planes->planes); ++i) {
+		struct rcar_du_plane *plane = &planes->planes[i];
 
-		plane->dev = rcdu;
+		plane->group = rgrp;
 		plane->hwindex = -1;
 		plane->alpha = 255;
 		plane->colorkey = RCAR_DU_COLORKEY_NONE;
@@ -475,8 +476,10 @@ int rcar_du_planes_init(struct rcar_du_device *rcdu)
 	return 0;
 }
 
-int rcar_du_planes_register(struct rcar_du_device *rcdu)
+int rcar_du_planes_register(struct rcar_du_group *rgrp)
 {
+	struct rcar_du_planes *planes = &rgrp->planes;
+	struct rcar_du_device *rcdu = rgrp->dev;
 	unsigned int i;
 	int ret;
 
@@ -487,7 +490,7 @@ int rcar_du_planes_register(struct rcar_du_device *rcdu)
 		if (plane == NULL)
 			return -ENOMEM;
 
-		plane->hwplane = &rcdu->planes.planes[i + 2];
+		plane->hwplane = &planes->planes[i + 2];
 		plane->hwplane->zpos = 1;
 
 		ret = drm_plane_init(rcdu->ddev, &plane->plane,
@@ -498,12 +501,12 @@ int rcar_du_planes_register(struct rcar_du_device *rcdu)
 			return ret;
 
 		drm_object_attach_property(&plane->plane.base,
-					   rcdu->planes.alpha, 255);
+					   planes->alpha, 255);
 		drm_object_attach_property(&plane->plane.base,
-					   rcdu->planes.colorkey,
+					   planes->colorkey,
 					   RCAR_DU_COLORKEY_NONE);
 		drm_object_attach_property(&plane->plane.base,
-					   rcdu->planes.zpos, 1);
+					   planes->zpos, 1);
 	}
 
 	return 0;
diff --git a/drivers/gpu/drm/rcar-du/rcar_du_plane.h b/drivers/gpu/drm/rcar-du/rcar_du_plane.h
index bcf6f76f56a..f94f9ce8499 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_plane.h
+++ b/drivers/gpu/drm/rcar-du/rcar_du_plane.h
@@ -19,8 +19,8 @@
 #include <drm/drmP.h>
 #include <drm/drm_crtc.h>
 
-struct rcar_du_device;
 struct rcar_du_format_info;
+struct rcar_du_group;
 
 /* The RCAR DU has 8 hardware planes, shared between KMS planes and CRTCs. As
  * using KMS planes requires at least one of the CRTCs being enabled, no more
@@ -33,7 +33,7 @@ struct rcar_du_format_info;
 #define RCAR_DU_NUM_SW_PLANES		9
 
 struct rcar_du_plane {
-	struct rcar_du_device *dev;
+	struct rcar_du_group *group;
 	struct drm_crtc *crtc;
 
 	bool enabled;
@@ -67,8 +67,8 @@ struct rcar_du_planes {
 	struct drm_property *zpos;
 };
 
-int rcar_du_planes_init(struct rcar_du_device *rcdu);
-int rcar_du_planes_register(struct rcar_du_device *rcdu);
+int rcar_du_planes_init(struct rcar_du_group *rgrp);
+int rcar_du_planes_register(struct rcar_du_group *rgrp);
 
 void rcar_du_plane_setup(struct rcar_du_plane *plane);
 void rcar_du_plane_update_base(struct rcar_du_plane *plane);