drm: sti: add Compositor

Compositor control all the input sub-device (VID, GDP)
and the mixer(s).
It is the main entry point for composition.
Layer interface is used to control the abstracted layers.

Add debug in mixer and GDP.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Reviewed-by: Rob Clark <robdclark@gmail.com>

drivers/gpu/drm/sti/Kconfig

@@ -1,5 +1,6 @@
 config DRM_STI
 	tristate "DRM Support for STMicroelectronics SoC stiH41x Series"
 	depends on DRM && (SOC_STIH415 || SOC_STIH416 || ARCH_MULTIPLATFORM)
+	select DRM_KMS_CMA_HELPER
 	help
 	  Choose this option to enable DRM on STM stiH41x chipset

drivers/gpu/drm/sti/Makefile

@@ -1,7 +1,9 @@
 sticompositor-y := \
+	sti_layer.o \
 	sti_mixer.o \
 	sti_gdp.o \
-	sti_vid.o
+	sti_vid.o \
+	sti_compositor.o
 
 stihdmi-y := sti_hdmi.o \
 	sti_hdmi_tx3g0c55phy.o \

drivers/gpu/drm/sti/sti_compositor.c

@@ -0,0 +1,236 @@
+/*
+ * Copyright (C) STMicroelectronics SA 2014
+ * Authors: Benjamin Gaignard <benjamin.gaignard@st.com>
+ *          Fabien Dessenne <fabien.dessenne@st.com>
+ *          for STMicroelectronics.
+ * License terms:  GNU General Public License (GPL), version 2
+ */
+
+#include <linux/component.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+
+#include <drm/drmP.h>
+
+#include "sti_compositor.h"
+#include "sti_gdp.h"
+#include "sti_vtg.h"
+
+/*
+ * stiH407 compositor properties
+ */
+struct sti_compositor_data stih407_compositor_data = {
+	.nb_subdev = 6,
+	.subdev_desc = {
+			{STI_GPD_SUBDEV, (int)STI_GDP_0, 0x100},
+			{STI_GPD_SUBDEV, (int)STI_GDP_1, 0x200},
+			{STI_GPD_SUBDEV, (int)STI_GDP_2, 0x300},
+			{STI_GPD_SUBDEV, (int)STI_GDP_3, 0x400},
+			{STI_VID_SUBDEV, (int)STI_VID_0, 0x700},
+			{STI_MIXER_MAIN_SUBDEV, STI_MIXER_MAIN, 0xC00}
+	},
+};
+
+/*
+ * stiH416 compositor properties
+ * Note:
+ * on stih416 MIXER_AUX has a different base address from MIXER_MAIN
+ * Moreover, GDPx is different for Main and Aux Mixer. So this subdev map does
+ * not fit for stiH416 if we want to enable the MIXER_AUX.
+ */
+struct sti_compositor_data stih416_compositor_data = {
+	.nb_subdev = 3,
+	.subdev_desc = {
+			{STI_GPD_SUBDEV, (int)STI_GDP_0, 0x100},
+			{STI_GPD_SUBDEV, (int)STI_GDP_1, 0x200},
+			{STI_MIXER_MAIN_SUBDEV, STI_MIXER_MAIN, 0xC00}
+	},
+};
+
+static int sti_compositor_init_subdev(struct sti_compositor *compo,
+		struct sti_compositor_subdev_descriptor *desc,
+		unsigned int array_size)
+{
+	unsigned int i, mixer_id = 0, layer_id = 0;
+
+	for (i = 0; i < array_size; i++) {
+		switch (desc[i].type) {
+		case STI_MIXER_MAIN_SUBDEV:
+		case STI_MIXER_AUX_SUBDEV:
+			compo->mixer[mixer_id++] =
+			    sti_mixer_create(compo->dev, desc[i].id,
+					     compo->regs + desc[i].offset);
+			break;
+		case STI_GPD_SUBDEV:
+		case STI_VID_SUBDEV:
+			compo->layer[layer_id++] =
+			    sti_layer_create(compo->dev, desc[i].id,
+					     compo->regs + desc[i].offset);
+			break;
+			/* case STI_CURSOR_SUBDEV : TODO */
+		default:
+			DRM_ERROR("Unknow subdev compoment type\n");
+			return 1;
+		}
+
+	}
+	compo->nb_mixers = mixer_id;
+	compo->nb_layers = layer_id;
+
+	return 0;
+}
+
+static int sti_compositor_bind(struct device *dev, struct device *master,
+	void *data)
+{
+	struct sti_compositor *compo = dev_get_drvdata(dev);
+	struct drm_device *drm_dev = data;
+	unsigned int i, crtc = 0, plane = 0;
+
+	drm_vblank_init(drm_dev, crtc);
+	/* Allow usage of vblank without having to call drm_irq_install */
+	drm_dev->irq_enabled = 1;
+
+
+	DRM_DEBUG_DRIVER("Initialized %d DRM CRTC(s) and %d DRM plane(s)\n",
+			 crtc, plane);
+	DRM_DEBUG_DRIVER("DRM plane(s) for VID/VDP not created yet\n");
+
+	return 0;
+}
+
+static void sti_compositor_unbind(struct device *dev, struct device *master,
+	void *data)
+{
+	/* do nothing */
+}
+
+static const struct component_ops sti_compositor_ops = {
+	.bind	= sti_compositor_bind,
+	.unbind	= sti_compositor_unbind,
+};
+
+static const struct of_device_id compositor_of_match[] = {
+	{
+		.compatible = "st,stih416-compositor",
+		.data = &stih416_compositor_data,
+	}, {
+		.compatible = "st,stih407-compositor",
+		.data = &stih407_compositor_data,
+	}, {
+		/* end node */
+	}
+};
+MODULE_DEVICE_TABLE(of, compositor_of_match);
+
+static int sti_compositor_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	struct device_node *vtg_np;
+	struct sti_compositor *compo;
+	struct resource *res;
+	int err;
+
+	compo = devm_kzalloc(dev, sizeof(*compo), GFP_KERNEL);
+	if (!compo) {
+		DRM_ERROR("Failed to allocate compositor context\n");
+		return -ENOMEM;
+	}
+	compo->dev = dev;
+
+	/* populate data structure depending on compatibility */
+	BUG_ON(!of_match_node(compositor_of_match, np)->data);
+
+	memcpy(&compo->data, of_match_node(compositor_of_match, np)->data,
+	       sizeof(struct sti_compositor_data));
+
+	/* Get Memory ressources */
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (res == NULL) {
+		DRM_ERROR("Get memory resource failed\n");
+		return -ENXIO;
+	}
+	compo->regs = devm_ioremap(dev, res->start, resource_size(res));
+	if (compo->regs == NULL) {
+		DRM_ERROR("Register mapping failed\n");
+		return -ENXIO;
+	}
+
+	/* Get clock resources */
+	compo->clk_compo_main = devm_clk_get(dev, "compo_main");
+	if (IS_ERR(compo->clk_compo_main)) {
+		DRM_ERROR("Cannot get compo_main clock\n");
+		return PTR_ERR(compo->clk_compo_main);
+	}
+
+	compo->clk_compo_aux = devm_clk_get(dev, "compo_aux");
+	if (IS_ERR(compo->clk_compo_aux)) {
+		DRM_ERROR("Cannot get compo_aux clock\n");
+		return PTR_ERR(compo->clk_compo_aux);
+	}
+
+	compo->clk_pix_main = devm_clk_get(dev, "pix_main");
+	if (IS_ERR(compo->clk_pix_main)) {
+		DRM_ERROR("Cannot get pix_main clock\n");
+		return PTR_ERR(compo->clk_pix_main);
+	}
+
+	compo->clk_pix_aux = devm_clk_get(dev, "pix_aux");
+	if (IS_ERR(compo->clk_pix_aux)) {
+		DRM_ERROR("Cannot get pix_aux clock\n");
+		return PTR_ERR(compo->clk_pix_aux);
+	}
+
+	/* Get reset resources */
+	compo->rst_main = devm_reset_control_get(dev, "compo-main");
+	/* Take compo main out of reset */
+	if (!IS_ERR(compo->rst_main))
+		reset_control_deassert(compo->rst_main);
+
+	compo->rst_aux = devm_reset_control_get(dev, "compo-aux");
+	/* Take compo aux out of reset */
+	if (!IS_ERR(compo->rst_aux))
+		reset_control_deassert(compo->rst_aux);
+
+	vtg_np = of_parse_phandle(pdev->dev.of_node, "st,vtg", 0);
+	if (vtg_np)
+		compo->vtg_main = of_vtg_find(vtg_np);
+
+	vtg_np = of_parse_phandle(pdev->dev.of_node, "st,vtg", 1);
+	if (vtg_np)
+		compo->vtg_aux = of_vtg_find(vtg_np);
+
+	/* Initialize compositor subdevices */
+	err = sti_compositor_init_subdev(compo, compo->data.subdev_desc,
+					 compo->data.nb_subdev);
+	if (err)
+		return err;
+
+	platform_set_drvdata(pdev, compo);
+
+	return component_add(&pdev->dev, &sti_compositor_ops);
+}
+
+static int sti_compositor_remove(struct platform_device *pdev)
+{
+	component_del(&pdev->dev, &sti_compositor_ops);
+	return 0;
+}
+
+static struct platform_driver sti_compositor_driver = {
+	.driver = {
+		.name = "sti-compositor",
+		.owner = THIS_MODULE,
+		.of_match_table = compositor_of_match,
+	},
+	.probe = sti_compositor_probe,
+	.remove = sti_compositor_remove,
+};
+
+module_platform_driver(sti_compositor_driver);
+
+MODULE_AUTHOR("Benjamin Gaignard <benjamin.gaignard@st.com>");
+MODULE_DESCRIPTION("STMicroelectronics SoC DRM driver");
+MODULE_LICENSE("GPL");

drivers/gpu/drm/sti/sti_compositor.h

@@ -0,0 +1,90 @@
+/*
+ * Copyright (C) STMicroelectronics SA 2014
+ * Authors: Benjamin Gaignard <benjamin.gaignard@st.com>
+ *          Fabien Dessenne <fabien.dessenne@st.com>
+ *          for STMicroelectronics.
+ * License terms:  GNU General Public License (GPL), version 2
+ */
+
+#ifndef _STI_COMPOSITOR_H_
+#define _STI_COMPOSITOR_H_
+
+#include <linux/clk.h>
+#include <linux/kernel.h>
+
+#include "sti_layer.h"
+#include "sti_mixer.h"
+
+#define WAIT_NEXT_VSYNC_MS      50 /*ms*/
+
+#define STI_MAX_LAYER 8
+#define STI_MAX_MIXER 2
+
+enum sti_compositor_subdev_type {
+	STI_MIXER_MAIN_SUBDEV,
+	STI_MIXER_AUX_SUBDEV,
+	STI_GPD_SUBDEV,
+	STI_VID_SUBDEV,
+	STI_CURSOR_SUBDEV,
+};
+
+struct sti_compositor_subdev_descriptor {
+	enum sti_compositor_subdev_type type;
+	int id;
+	unsigned int offset;
+};
+
+/**
+ * STI Compositor data structure
+ *
+ * @nb_subdev: number of subdevices supported by the compositor
+ * @subdev_desc: subdev list description
+ */
+#define MAX_SUBDEV 9
+struct sti_compositor_data {
+	unsigned int nb_subdev;
+	struct sti_compositor_subdev_descriptor subdev_desc[MAX_SUBDEV];
+};
+
+/**
+ * STI Compositor structure
+ *
+ * @dev: driver device
+ * @regs: registers (main)
+ * @data: device data
+ * @clk_compo_main: clock for main compo
+ * @clk_compo_aux: clock for aux compo
+ * @clk_pix_main: pixel clock for main path
+ * @clk_pix_aux: pixel clock for aux path
+ * @rst_main: reset control of the main path
+ * @rst_aux: reset control of the aux path
+ * @mixer: array of mixers
+ * @vtg_main: vtg for main data path
+ * @vtg_aux: vtg for auxillary data path
+ * @layer: array of layers
+ * @nb_mixers: number of mixers for this compositor
+ * @nb_layers: number of layers (GDP,VID,...) for this compositor
+ * @enable: true if compositor is enable else false
+ * @vtg_vblank_nb: callback for VTG VSYNC notification
+ */
+struct sti_compositor {
+	struct device *dev;
+	void __iomem *regs;
+	struct sti_compositor_data data;
+	struct clk *clk_compo_main;
+	struct clk *clk_compo_aux;
+	struct clk *clk_pix_main;
+	struct clk *clk_pix_aux;
+	struct reset_control *rst_main;
+	struct reset_control *rst_aux;
+	struct sti_mixer *mixer[STI_MAX_MIXER];
+	struct sti_vtg *vtg_main;
+	struct sti_vtg *vtg_aux;
+	struct sti_layer *layer[STI_MAX_LAYER];
+	int nb_mixers;
+	int nb_layers;
+	bool enable;
+	struct notifier_block vtg_vblank_nb;
+};
+
+#endif

drivers/gpu/drm/sti/sti_gdp.c

@@ -9,6 +9,7 @@
 #include <linux/clk.h>
 #include <linux/dma-mapping.h>
 
+#include "sti_compositor.h"
 #include "sti_gdp.h"
 #include "sti_layer.h"
 #include "sti_vtg.h"
@@ -182,6 +183,10 @@ static struct sti_gdp_node_list *sti_gdp_get_free_nodes(struct sti_layer *layer)
 		    (virt_nvn != gdp->node_list[i].top_field))
 			return &gdp->node_list[i];
 
+	/* in hazardious cases restart with the first node */
+	DRM_ERROR("inconsistent NVN for %s: 0x%08X\n",
+			sti_layer_to_str(layer), hw_nvn);
+
 end:
 	return &gdp->node_list[0];
 }
@@ -215,6 +220,9 @@ struct sti_gdp_node_list *sti_gdp_get_current_nodes(struct sti_layer *layer)
 			return &gdp->node_list[i];
 
 end:
+	DRM_DEBUG_DRIVER("Warning, NVN 0x%08X for %s does not match any node\n",
+				hw_nvn, sti_layer_to_str(layer));
+
 	return NULL;
 }
 
@@ -235,6 +243,7 @@ static int sti_gdp_prepare_layer(struct sti_layer *layer, bool first_prepare)
 	struct drm_display_mode *mode = layer->mode;
 	struct device *dev = layer->dev;
 	struct sti_gdp *gdp = to_sti_gdp(layer);
+	struct sti_compositor *compo = dev_get_drvdata(dev);
 	int format;
 	unsigned int depth, bpp;
 	int rate = mode->clock * 1000;
@@ -245,6 +254,9 @@ static int sti_gdp_prepare_layer(struct sti_layer *layer, bool first_prepare)
 	top_field = list->top_field;
 	btm_field = list->btm_field;
 
+	dev_dbg(dev, "%s %s top_node:0x%p btm_node:0x%p\n", __func__,
+			sti_layer_to_str(layer), top_field, btm_field);
+
 	/* Build the top field from layer params */
 	top_field->gam_gdp_agc = GAM_GDP_AGC_FULL_RANGE;
 	top_field->gam_gdp_ctl = WAIT_NEXT_VSYNC;
@@ -289,6 +301,14 @@ static int sti_gdp_prepare_layer(struct sti_layer *layer, bool first_prepare)
 		    layer->pitches[0];
 
 	if (first_prepare) {
+		/* Register gdp callback */
+		if (sti_vtg_register_client(layer->mixer_id == STI_MIXER_MAIN ?
+				compo->vtg_main : compo->vtg_aux,
+				&gdp->vtg_field_nb, layer->mixer_id)) {
+			DRM_ERROR("Cannot register VTG notifier\n");
+			return 1;
+		}
+
 		/* Set and enable gdp clock */
 		if (gdp->clk_pix) {
 			res = clk_set_rate(gdp->clk_pix, rate);
@@ -333,6 +353,9 @@ static int sti_gdp_commit_layer(struct sti_layer *layer)
 	u32 dma_updated_btm = virt_to_dma(layer->dev, updated_btm_node);
 	struct sti_gdp_node_list *curr_list = sti_gdp_get_current_nodes(layer);
 
+	dev_dbg(layer->dev, "%s %s top/btm_node:0x%p/0x%p\n", __func__,
+			sti_layer_to_str(layer),
+			updated_top_node, updated_btm_node);
 	dev_dbg(layer->dev, "Current NVN:0x%X\n",
 		readl(layer->regs + GAM_GDP_NVN_OFFSET));
 	dev_dbg(layer->dev, "Posted buff: %lx current buff: %x\n",
@@ -342,6 +365,9 @@ static int sti_gdp_commit_layer(struct sti_layer *layer)
 	if (curr_list == NULL) {
 		/* First update or invalid node should directly write in the
 		 * hw register */
+		DRM_DEBUG_DRIVER("%s first update (or invalid node)",
+				sti_layer_to_str(layer));
+
 		writel(gdp->is_curr_top == true ?
 				dma_updated_btm : dma_updated_top,
 				layer->regs + GAM_GDP_NVN_OFFSET);
@@ -380,6 +406,9 @@ static int sti_gdp_disable_layer(struct sti_layer *layer)
 {
 	unsigned int i;
 	struct sti_gdp *gdp = to_sti_gdp(layer);
+	struct sti_compositor *compo = dev_get_drvdata(layer->dev);
+
+	DRM_DEBUG_DRIVER("%s\n", sti_layer_to_str(layer));
 
 	/* Set the nodes as 'to be ignored on mixer' */
 	for (i = 0; i < GDP_NODE_NB_BANK; i++) {
@@ -387,6 +416,10 @@ static int sti_gdp_disable_layer(struct sti_layer *layer)
 		gdp->node_list[i].btm_field->gam_gdp_ppt |= GAM_GDP_PPT_IGNORE;
 	}
 
+	if (sti_vtg_unregister_client(layer->mixer_id == STI_MIXER_MAIN ?
+			compo->vtg_main : compo->vtg_aux, &gdp->vtg_field_nb))
+		DRM_DEBUG_DRIVER("Warning: cannot unregister VTG notifier\n");
+
 	if (gdp->clk_pix)
 		clk_disable_unprepare(gdp->clk_pix);
 

drivers/gpu/drm/sti/sti_layer.c

@@ -0,0 +1,197 @@
+/*
+ * Copyright (C) STMicroelectronics SA 2014
+ * Authors: Benjamin Gaignard <benjamin.gaignard@st.com>
+ *          Fabien Dessenne <fabien.dessenne@st.com>
+ *          for STMicroelectronics.
+ * License terms:  GNU General Public License (GPL), version 2
+ */
+
+#include <drm/drmP.h>
+#include <drm/drm_gem_cma_helper.h>
+#include <drm/drm_fb_cma_helper.h>
+
+#include "sti_compositor.h"
+#include "sti_gdp.h"
+#include "sti_layer.h"
+#include "sti_vid.h"
+
+const char *sti_layer_to_str(struct sti_layer *layer)
+{
+	switch (layer->desc) {
+	case STI_GDP_0:
+		return "GDP0";
+	case STI_GDP_1:
+		return "GDP1";
+	case STI_GDP_2:
+		return "GDP2";
+	case STI_GDP_3:
+		return "GDP3";
+	case STI_VID_0:
+		return "VID0";
+	case STI_VID_1:
+		return "VID1";
+	case STI_CURSOR:
+		return "CURSOR";
+	default:
+		return "<UNKNOWN LAYER>";
+	}
+}
+
+struct sti_layer *sti_layer_create(struct device *dev, int desc,
+				   void __iomem *baseaddr)
+{
+
+	struct sti_layer *layer = NULL;
+
+	switch (desc & STI_LAYER_TYPE_MASK) {
+	case STI_GDP:
+		layer = sti_gdp_create(dev, desc);
+		break;
+	case STI_VID:
+		layer = sti_vid_create(dev);
+		break;
+	}
+
+	if (!layer) {
+		DRM_ERROR("Failed to create layer\n");
+		return NULL;
+	}
+
+	layer->desc = desc;
+	layer->dev = dev;
+	layer->regs = baseaddr;
+
+	layer->ops->init(layer);
+
+	DRM_DEBUG_DRIVER("%s created\n", sti_layer_to_str(layer));
+
+	return layer;
+}
+
+int sti_layer_prepare(struct sti_layer *layer, struct drm_framebuffer *fb,
+		      struct drm_display_mode *mode, int mixer_id,
+		      int dest_x, int dest_y, int dest_w, int dest_h,
+		      int src_x, int src_y, int src_w, int src_h)
+{
+	int ret;
+	unsigned int i;
+	struct drm_gem_cma_object *cma_obj;
+
+	if (!layer || !fb || !mode) {
+		DRM_ERROR("Null fb, layer or mode\n");
+		return 1;
+	}
+
+	cma_obj = drm_fb_cma_get_gem_obj(fb, 0);
+	if (!cma_obj) {
+		DRM_ERROR("Can't get CMA GEM object for fb\n");
+		return 1;
+	}
+
+	layer->fb = fb;
+	layer->mode = mode;
+	layer->mixer_id = mixer_id;
+	layer->dst_x = dest_x;
+	layer->dst_y = dest_y;
+	layer->dst_w = clamp_val(dest_w, 0, mode->crtc_hdisplay - dest_x);
+	layer->dst_h = clamp_val(dest_h, 0, mode->crtc_vdisplay - dest_y);
+	layer->src_x = src_x;
+	layer->src_y = src_y;
+	layer->src_w = src_w;
+	layer->src_h = src_h;
+	layer->format = fb->pixel_format;
+	layer->paddr = cma_obj->paddr;
+	for (i = 0; i < 4; i++) {
+		layer->pitches[i] = fb->pitches[i];
+		layer->offsets[i] = fb->offsets[i];
+	}
+
+	DRM_DEBUG_DRIVER("%s is associated with mixer_id %d\n",
+			 sti_layer_to_str(layer),
+			 layer->mixer_id);
+	DRM_DEBUG_DRIVER("%s dst=(%dx%d)@(%d,%d) - src=(%dx%d)@(%d,%d)\n",
+			 sti_layer_to_str(layer),
+			 layer->dst_w, layer->dst_h, layer->dst_x, layer->dst_y,
+			 layer->src_w, layer->src_h, layer->src_x,
+			 layer->src_y);
+
+	DRM_DEBUG_DRIVER("drm FB:%d format:%.4s phys@:0x%lx\n", fb->base.id,
+			 (char *)&layer->format, (unsigned long)layer->paddr);
+
+	if (!layer->ops->prepare)
+		goto err_no_prepare;
+
+	ret = layer->ops->prepare(layer, !layer->enabled);
+	if (!ret)
+		layer->enabled = true;
+
+	return ret;
+
+err_no_prepare:
+	DRM_ERROR("Cannot prepare\n");
+	return 1;
+}
+
+int sti_layer_commit(struct sti_layer *layer)
+{
+	if (!layer)
+		return 1;
+
+	if (!layer->ops->commit)
+		goto err_no_commit;
+
+	return layer->ops->commit(layer);
+
+err_no_commit:
+	DRM_ERROR("Cannot commit\n");
+	return 1;
+}
+
+int sti_layer_disable(struct sti_layer *layer)
+{
+	int ret;
+
+	DRM_DEBUG_DRIVER("%s\n", sti_layer_to_str(layer));
+	if (!layer)
+		return 1;
+
+	if (!layer->enabled)
+		return 0;
+
+	if (!layer->ops->disable)
+		goto err_no_disable;
+
+	ret = layer->ops->disable(layer);
+	if (!ret)
+		layer->enabled = false;
+	else
+		DRM_ERROR("Disable failed\n");
+
+	return ret;
+
+err_no_disable:
+	DRM_ERROR("Cannot disable\n");
+	return 1;
+}
+
+const uint32_t *sti_layer_get_formats(struct sti_layer *layer)
+{
+	if (!layer)
+		return NULL;
+
+	if (!layer->ops->get_formats)
+		return NULL;
+
+	return layer->ops->get_formats(layer);
+}
+
+unsigned int sti_layer_get_nb_formats(struct sti_layer *layer)
+{
+	if (!layer)
+		return 0;
+
+	if (!layer->ops->get_nb_formats)
+		return 0;
+
+	return layer->ops->get_nb_formats(layer);
+}

drivers/gpu/drm/sti/sti_mixer.c

@@ -6,6 +6,7 @@
  * License terms:  GNU General Public License (GPL), version 2
  */
 
+#include "sti_compositor.h"
 #include "sti_mixer.h"
 #include "sti_vtg.h"
 
@@ -133,6 +134,8 @@ int sti_mixer_set_layer_depth(struct sti_mixer *mixer, struct sti_layer *layer)
 	mask = GAM_DEPTH_MASK_ID << (3 * depth);
 	layer_id = layer_id << (3 * depth);
 
+	DRM_DEBUG_DRIVER("%s %s depth=%d\n", sti_mixer_to_str(mixer),
+			 sti_layer_to_str(layer), depth);
 	dev_dbg(mixer->dev, "GAM_MIXER_CRB val 0x%x mask 0x%x\n",
 		layer_id, mask);
 
@@ -195,6 +198,9 @@ int sti_mixer_set_layer_status(struct sti_mixer *mixer,
 {
 	u32 mask, val;
 
+	DRM_DEBUG_DRIVER("%s %s %s\n", status ? "enable" : "disable",
+			 sti_mixer_to_str(mixer), sti_layer_to_str(layer));
+
 	mask = sti_mixer_get_layer_mask(layer);
 	if (!mask) {
 		DRM_ERROR("Can not find layer mask\n");