drm: sti: add GDP layer

Generic Display Pipeline are one of the compositor input sub-devices.
GDP are dedicated to graphic input like RGB plans.
GDP is part of Compositor hardware block which will be introduce later.

A sti_layer structure is used to abstract GDP calls from Compositor.

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

4 files changed, 660 insertions, 1 deletions

diff --git a/drivers/gpu/drm/sti/Makefile b/drivers/gpu/drm/sti/Makefile
index 5f6d96d27f3b..7de757f7eb38 100644
--- a/drivers/gpu/drm/sti/Makefile
+++ b/drivers/gpu/drm/sti/Makefile
@@ -1,3 +1,6 @@
+sticompositor-y := \
+	sti_gdp.o
+
 stihdmi-y := sti_hdmi.o \
 	sti_hdmi_tx3g0c55phy.o \
 	sti_hdmi_tx3g4c28phy.o \
@@ -7,4 +10,5 @@ obj-$(CONFIG_DRM_STI) = \
 	sti_vtac.o \
 	stihdmi.o \
 	sti_hda.o \
-	sti_tvout.o
\ No newline at end of file
+	sti_tvout.o \
+	sticompositor.o
diff --git a/drivers/gpu/drm/sti/sti_gdp.c b/drivers/gpu/drm/sti/sti_gdp.c
new file mode 100644
index 000000000000..7f557676704d
--- /dev/null
+++ b/drivers/gpu/drm/sti/sti_gdp.c
@@ -0,0 +1,516 @@
+/*
+ * 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/clk.h>
+#include <linux/dma-mapping.h>
+
+#include "sti_gdp.h"
+#include "sti_layer.h"
+#include "sti_vtg.h"
+
+#define ENA_COLOR_FILL  BIT(8)
+#define WAIT_NEXT_VSYNC BIT(31)
+
+/* GDP color formats */
+#define GDP_RGB565      0x00
+#define GDP_RGB888      0x01
+#define GDP_RGB888_32   0x02
+#define GDP_ARGB8565    0x04
+#define GDP_ARGB8888    0x05
+#define GDP_ARGB1555    0x06
+#define GDP_ARGB4444    0x07
+#define GDP_CLUT8       0x0B
+#define GDP_YCBR888     0x10
+#define GDP_YCBR422R    0x12
+#define GDP_AYCBR8888   0x15
+
+#define GAM_GDP_CTL_OFFSET      0x00
+#define GAM_GDP_AGC_OFFSET      0x04
+#define GAM_GDP_VPO_OFFSET      0x0C
+#define GAM_GDP_VPS_OFFSET      0x10
+#define GAM_GDP_PML_OFFSET      0x14
+#define GAM_GDP_PMP_OFFSET      0x18
+#define GAM_GDP_SIZE_OFFSET     0x1C
+#define GAM_GDP_NVN_OFFSET      0x24
+#define GAM_GDP_KEY1_OFFSET     0x28
+#define GAM_GDP_KEY2_OFFSET     0x2C
+#define GAM_GDP_PPT_OFFSET      0x34
+#define GAM_GDP_CML_OFFSET      0x3C
+#define GAM_GDP_MST_OFFSET      0x68
+
+#define GAM_GDP_ALPHARANGE_255  BIT(5)
+#define GAM_GDP_AGC_FULL_RANGE  0x00808080
+#define GAM_GDP_PPT_IGNORE      (BIT(1) | BIT(0))
+#define GAM_GDP_SIZE_MAX        0x7FF
+
+#define GDP_NODE_NB_BANK	2
+#define GDP_NODE_PER_FIELD	2
+
+struct sti_gdp_node {
+	u32 gam_gdp_ctl;
+	u32 gam_gdp_agc;
+	u32 reserved1;
+	u32 gam_gdp_vpo;
+	u32 gam_gdp_vps;
+	u32 gam_gdp_pml;
+	u32 gam_gdp_pmp;
+	u32 gam_gdp_size;
+	u32 reserved2;
+	u32 gam_gdp_nvn;
+	u32 gam_gdp_key1;
+	u32 gam_gdp_key2;
+	u32 reserved3;
+	u32 gam_gdp_ppt;
+	u32 reserved4;
+	u32 gam_gdp_cml;
+};
+
+struct sti_gdp_node_list {
+	struct sti_gdp_node *top_field;
+	struct sti_gdp_node *btm_field;
+};
+
+/**
+ * STI GDP structure
+ *
+ * @layer:		layer structure
+ * @clk_pix:            pixel clock for the current gdp
+ * @vtg_field_nb:       callback for VTG FIELD (top or bottom) notification
+ * @is_curr_top:        true if the current node processed is the top field
+ * @node_list:		array of node list
+ */
+struct sti_gdp {
+	struct sti_layer layer;
+	struct clk *clk_pix;
+	struct notifier_block vtg_field_nb;
+	bool is_curr_top;
+	struct sti_gdp_node_list node_list[GDP_NODE_NB_BANK];
+};
+
+#define to_sti_gdp(x) container_of(x, struct sti_gdp, layer)
+
+static const uint32_t gdp_supported_formats[] = {
+	DRM_FORMAT_XRGB8888,
+	DRM_FORMAT_ARGB8888,
+	DRM_FORMAT_ARGB4444,
+	DRM_FORMAT_ARGB1555,
+	DRM_FORMAT_RGB565,
+	DRM_FORMAT_RGB888,
+	DRM_FORMAT_AYUV,
+	DRM_FORMAT_YUV444,
+	DRM_FORMAT_VYUY,
+	DRM_FORMAT_C8,
+};
+
+static const uint32_t *sti_gdp_get_formats(struct sti_layer *layer)
+{
+	return gdp_supported_formats;
+}
+
+static unsigned int sti_gdp_get_nb_formats(struct sti_layer *layer)
+{
+	return ARRAY_SIZE(gdp_supported_formats);
+}
+
+static int sti_gdp_fourcc2format(int fourcc)
+{
+	switch (fourcc) {
+	case DRM_FORMAT_XRGB8888:
+		return GDP_RGB888_32;
+	case DRM_FORMAT_ARGB8888:
+		return GDP_ARGB8888;
+	case DRM_FORMAT_ARGB4444:
+		return GDP_ARGB4444;
+	case DRM_FORMAT_ARGB1555:
+		return GDP_ARGB1555;
+	case DRM_FORMAT_RGB565:
+		return GDP_RGB565;
+	case DRM_FORMAT_RGB888:
+		return GDP_RGB888;
+	case DRM_FORMAT_AYUV:
+		return GDP_AYCBR8888;
+	case DRM_FORMAT_YUV444:
+		return GDP_YCBR888;
+	case DRM_FORMAT_VYUY:
+		return GDP_YCBR422R;
+	case DRM_FORMAT_C8:
+		return GDP_CLUT8;
+	}
+	return -1;
+}
+
+static int sti_gdp_get_alpharange(int format)
+{
+	switch (format) {
+	case GDP_ARGB8565:
+	case GDP_ARGB8888:
+	case GDP_AYCBR8888:
+		return GAM_GDP_ALPHARANGE_255;
+	}
+	return 0;
+}
+
+/**
+ * sti_gdp_get_free_nodes
+ * @layer: gdp layer
+ *
+ * Look for a GDP node list that is not currently read by the HW.
+ *
+ * RETURNS:
+ * Pointer to the free GDP node list
+ */
+static struct sti_gdp_node_list *sti_gdp_get_free_nodes(struct sti_layer *layer)
+{
+	int hw_nvn;
+	void *virt_nvn;
+	struct sti_gdp *gdp = to_sti_gdp(layer);
+	unsigned int i;
+
+	hw_nvn = readl(layer->regs + GAM_GDP_NVN_OFFSET);
+	if (!hw_nvn)
+		goto end;
+
+	virt_nvn = dma_to_virt(layer->dev, (dma_addr_t) hw_nvn);
+
+	for (i = 0; i < GDP_NODE_NB_BANK; i++)
+		if ((virt_nvn != gdp->node_list[i].btm_field) &&
+		    (virt_nvn != gdp->node_list[i].top_field))
+			return &gdp->node_list[i];
+
+end:
+	return &gdp->node_list[0];
+}
+
+/**
+ * sti_gdp_get_current_nodes
+ * @layer: GDP layer
+ *
+ * Look for GDP nodes that are currently read by the HW.
+ *
+ * RETURNS:
+ * Pointer to the current GDP node list
+ */
+static
+struct sti_gdp_node_list *sti_gdp_get_current_nodes(struct sti_layer *layer)
+{
+	int hw_nvn;
+	void *virt_nvn;
+	struct sti_gdp *gdp = to_sti_gdp(layer);
+	unsigned int i;
+
+	hw_nvn = readl(layer->regs + GAM_GDP_NVN_OFFSET);
+	if (!hw_nvn)
+		goto end;
+
+	virt_nvn = dma_to_virt(layer->dev, (dma_addr_t) hw_nvn);
+
+	for (i = 0; i < GDP_NODE_NB_BANK; i++)
+		if ((virt_nvn == gdp->node_list[i].btm_field) ||
+				(virt_nvn == gdp->node_list[i].top_field))
+			return &gdp->node_list[i];
+
+end:
+	return NULL;
+}
+
+/**
+ * sti_gdp_prepare_layer
+ * @lay: gdp layer
+ * @first_prepare: true if it is the first time this function is called
+ *
+ * Update the free GDP node list according to the layer properties.
+ *
+ * RETURNS:
+ * 0 on success.
+ */
+static int sti_gdp_prepare_layer(struct sti_layer *layer, bool first_prepare)
+{
+	struct sti_gdp_node_list *list;
+	struct sti_gdp_node *top_field, *btm_field;
+	struct drm_display_mode *mode = layer->mode;
+	struct device *dev = layer->dev;
+	struct sti_gdp *gdp = to_sti_gdp(layer);
+	int format;
+	unsigned int depth, bpp;
+	int rate = mode->clock * 1000;
+	int res;
+	u32 ydo, xdo, yds, xds;
+
+	list = sti_gdp_get_free_nodes(layer);
+	top_field = list->top_field;
+	btm_field = list->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;
+	format = sti_gdp_fourcc2format(layer->format);
+	if (format == -1) {
+		DRM_ERROR("Format not supported by GDP %.4s\n",
+			  (char *)&layer->format);
+		return 1;
+	}
+	top_field->gam_gdp_ctl |= format;
+	top_field->gam_gdp_ctl |= sti_gdp_get_alpharange(format);
+	top_field->gam_gdp_ppt &= ~GAM_GDP_PPT_IGNORE;
+
+	/* pixel memory location */
+	drm_fb_get_bpp_depth(layer->format, &depth, &bpp);
+	top_field->gam_gdp_pml = (u32) layer->paddr + layer->offsets[0];
+	top_field->gam_gdp_pml += layer->src_x * (bpp >> 3);
+	top_field->gam_gdp_pml += layer->src_y * layer->pitches[0];
+
+	/* input parameters */
+	top_field->gam_gdp_pmp = layer->pitches[0];
+	top_field->gam_gdp_size =
+	    clamp_val(layer->src_h, 0, GAM_GDP_SIZE_MAX) << 16 |
+	    clamp_val(layer->src_w, 0, GAM_GDP_SIZE_MAX);
+
+	/* output parameters */
+	ydo = sti_vtg_get_line_number(*mode, layer->dst_y);
+	yds = sti_vtg_get_line_number(*mode, layer->dst_y + layer->dst_h - 1);
+	xdo = sti_vtg_get_pixel_number(*mode, layer->dst_x);
+	xds = sti_vtg_get_pixel_number(*mode, layer->dst_x + layer->dst_w - 1);
+	top_field->gam_gdp_vpo = (ydo << 16) | xdo;
+	top_field->gam_gdp_vps = (yds << 16) | xds;
+
+	/* Same content and chained together */
+	memcpy(btm_field, top_field, sizeof(*btm_field));
+	top_field->gam_gdp_nvn = virt_to_dma(dev, btm_field);
+	btm_field->gam_gdp_nvn = virt_to_dma(dev, top_field);
+
+	/* Interlaced mode */
+	if (layer->mode->flags & DRM_MODE_FLAG_INTERLACE)
+		btm_field->gam_gdp_pml = top_field->gam_gdp_pml +
+		    layer->pitches[0];
+
+	if (first_prepare) {
+		/* Set and enable gdp clock */
+		if (gdp->clk_pix) {
+			res = clk_set_rate(gdp->clk_pix, rate);
+			if (res < 0) {
+				DRM_ERROR("Cannot set rate (%dHz) for gdp\n",
+						rate);
+				return 1;
+			}
+
+			if (clk_prepare_enable(gdp->clk_pix)) {
+				DRM_ERROR("Failed to prepare/enable gdp\n");
+				return 1;
+			}
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * sti_gdp_commit_layer
+ * @lay: gdp layer
+ *
+ * Update the NVN field of the 'right' field of the current GDP node (being
+ * used by the HW) with the address of the updated ('free') top field GDP node.
+ * - In interlaced mode the 'right' field is the bottom field as we update
+ *   frames starting from their top field
+ * - In progressive mode, we update both bottom and top fields which are
+ *   equal nodes.
+ * At the next VSYNC, the updated node list will be used by the HW.
+ *
+ * RETURNS:
+ * 0 on success.
+ */
+static int sti_gdp_commit_layer(struct sti_layer *layer)
+{
+	struct sti_gdp_node_list *updated_list = sti_gdp_get_free_nodes(layer);
+	struct sti_gdp_node *updated_top_node = updated_list->top_field;
+	struct sti_gdp_node *updated_btm_node = updated_list->btm_field;
+	struct sti_gdp *gdp = to_sti_gdp(layer);
+	u32 dma_updated_top = virt_to_dma(layer->dev, updated_top_node);
+	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, "Current NVN:0x%X\n",
+		readl(layer->regs + GAM_GDP_NVN_OFFSET));
+	dev_dbg(layer->dev, "Posted buff: %lx current buff: %x\n",
+		(unsigned long)layer->paddr,
+		readl(layer->regs + GAM_GDP_PML_OFFSET));
+
+	if (curr_list == NULL) {
+		/* First update or invalid node should directly write in the
+		 * hw register */
+		writel(gdp->is_curr_top == true ?
+				dma_updated_btm : dma_updated_top,
+				layer->regs + GAM_GDP_NVN_OFFSET);
+		return 0;
+	}
+
+	if (layer->mode->flags & DRM_MODE_FLAG_INTERLACE) {
+		if (gdp->is_curr_top == true) {
+			/* Do not update in the middle of the frame, but
+			 * postpone the update after the bottom field has
+			 * been displayed */
+			curr_list->btm_field->gam_gdp_nvn = dma_updated_top;
+		} else {
+			/* Direct update to avoid one frame delay */
+			writel(dma_updated_top,
+				layer->regs + GAM_GDP_NVN_OFFSET);
+		}
+	} else {
+		/* Direct update for progressive to avoid one frame delay */
+		writel(dma_updated_top, layer->regs + GAM_GDP_NVN_OFFSET);
+	}
+
+	return 0;
+}
+
+/**
+ * sti_gdp_disable_layer
+ * @lay: gdp layer
+ *
+ * Disable a GDP.
+ *
+ * RETURNS:
+ * 0 on success.
+ */
+static int sti_gdp_disable_layer(struct sti_layer *layer)
+{
+	unsigned int i;
+	struct sti_gdp *gdp = to_sti_gdp(layer);
+
+	/* Set the nodes as 'to be ignored on mixer' */
+	for (i = 0; i < GDP_NODE_NB_BANK; i++) {
+		gdp->node_list[i].top_field->gam_gdp_ppt |= GAM_GDP_PPT_IGNORE;
+		gdp->node_list[i].btm_field->gam_gdp_ppt |= GAM_GDP_PPT_IGNORE;
+	}
+
+	if (gdp->clk_pix)
+		clk_disable_unprepare(gdp->clk_pix);
+
+	return 0;
+}
+
+/**
+ * sti_gdp_field_cb
+ * @nb: notifier block
+ * @event: event message
+ * @data: private data
+ *
+ * Handle VTG top field and bottom field event.
+ *
+ * RETURNS:
+ * 0 on success.
+ */
+int sti_gdp_field_cb(struct notifier_block *nb,
+		unsigned long event, void *data)
+{
+	struct sti_gdp *gdp = container_of(nb, struct sti_gdp, vtg_field_nb);
+
+	switch (event) {
+	case VTG_TOP_FIELD_EVENT:
+		gdp->is_curr_top = true;
+		break;
+	case VTG_BOTTOM_FIELD_EVENT:
+		gdp->is_curr_top = false;
+		break;
+	default:
+		DRM_ERROR("unsupported event: %lu\n", event);
+		break;
+	}
+
+	return 0;
+}
+
+static void sti_gdp_init(struct sti_layer *layer)
+{
+	struct sti_gdp *gdp = to_sti_gdp(layer);
+	struct device_node *np = layer->dev->of_node;
+	dma_addr_t dma;
+	void *base;
+	unsigned int i, size;
+
+	/* Allocate all the nodes within a single memory page */
+	size = sizeof(struct sti_gdp_node) *
+	    GDP_NODE_PER_FIELD * GDP_NODE_NB_BANK;
+
+	base = dma_alloc_writecombine(layer->dev,
+			size, &dma, GFP_KERNEL | GFP_DMA);
+	if (!base) {
+		DRM_ERROR("Failed to allocate memory for GDP node\n");
+		return;
+	}
+	memset(base, 0, size);
+
+	for (i = 0; i < GDP_NODE_NB_BANK; i++) {
+		if (virt_to_dma(layer->dev, base) & 0xF) {
+			DRM_ERROR("Mem alignment failed\n");
+			return;
+		}
+		gdp->node_list[i].top_field = base;
+		DRM_DEBUG_DRIVER("node[%d].top_field=%p\n", i, base);
+		base += sizeof(struct sti_gdp_node);
+
+		if (virt_to_dma(layer->dev, base) & 0xF) {
+			DRM_ERROR("Mem alignment failed\n");
+			return;
+		}
+		gdp->node_list[i].btm_field = base;
+		DRM_DEBUG_DRIVER("node[%d].btm_field=%p\n", i, base);
+		base += sizeof(struct sti_gdp_node);
+	}
+
+	if (of_device_is_compatible(np, "st,stih407-compositor")) {
+		/* GDP of STiH407 chip have its own pixel clock */
+		char *clk_name;
+
+		switch (layer->desc) {
+		case STI_GDP_0:
+			clk_name = "pix_gdp1";
+			break;
+		case STI_GDP_1:
+			clk_name = "pix_gdp2";
+			break;
+		case STI_GDP_2:
+			clk_name = "pix_gdp3";
+			break;
+		case STI_GDP_3:
+			clk_name = "pix_gdp4";
+			break;
+		default:
+			DRM_ERROR("GDP id not recognized\n");
+			return;
+		}
+
+		gdp->clk_pix = devm_clk_get(layer->dev, clk_name);
+		if (IS_ERR(gdp->clk_pix))
+			DRM_ERROR("Cannot get %s clock\n", clk_name);
+	}
+}
+
+static const struct sti_layer_funcs gdp_ops = {
+	.get_formats = sti_gdp_get_formats,
+	.get_nb_formats = sti_gdp_get_nb_formats,
+	.init = sti_gdp_init,
+	.prepare = sti_gdp_prepare_layer,
+	.commit = sti_gdp_commit_layer,
+	.disable = sti_gdp_disable_layer,
+};
+
+struct sti_layer *sti_gdp_create(struct device *dev, int id)
+{
+	struct sti_gdp *gdp;
+
+	gdp = devm_kzalloc(dev, sizeof(*gdp), GFP_KERNEL);
+	if (!gdp) {
+		DRM_ERROR("Failed to allocate memory for GDP\n");
+		return NULL;
+	}
+
+	gdp->layer.ops = &gdp_ops;
+	gdp->vtg_field_nb.notifier_call = sti_gdp_field_cb;
+
+	return (struct sti_layer *)gdp;
+}
diff --git a/drivers/gpu/drm/sti/sti_gdp.h b/drivers/gpu/drm/sti/sti_gdp.h
new file mode 100644
index 000000000000..1dab68274ad3
--- /dev/null
+++ b/drivers/gpu/drm/sti/sti_gdp.h
@@ -0,0 +1,16 @@
+/*
+ * 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_GDP_H_
+#define _STI_GDP_H_
+
+#include <linux/types.h>
+
+struct sti_layer *sti_gdp_create(struct device *dev, int id);
+
+#endif
diff --git a/drivers/gpu/drm/sti/sti_layer.h b/drivers/gpu/drm/sti/sti_layer.h
new file mode 100644
index 000000000000..198c3774cc12
--- /dev/null
+++ b/drivers/gpu/drm/sti/sti_layer.h
@@ -0,0 +1,123 @@
+/*
+ * 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_LAYER_H_
+#define _STI_LAYER_H_
+
+#include <drm/drmP.h>
+
+#define to_sti_layer(x) container_of(x, struct sti_layer, plane)
+
+#define STI_LAYER_TYPE_SHIFT 8
+#define STI_LAYER_TYPE_MASK (~((1<<STI_LAYER_TYPE_SHIFT)-1))
+
+struct sti_layer;
+
+enum sti_layer_type {
+	STI_GDP = 1 << STI_LAYER_TYPE_SHIFT,
+	STI_VID = 2 << STI_LAYER_TYPE_SHIFT,
+	STI_CUR = 3 << STI_LAYER_TYPE_SHIFT,
+	STI_BCK = 4 << STI_LAYER_TYPE_SHIFT
+};
+
+enum sti_layer_id_of_type {
+	STI_ID_0 = 0,
+	STI_ID_1 = 1,
+	STI_ID_2 = 2,
+	STI_ID_3 = 3
+};
+
+enum sti_layer_desc {
+	STI_GDP_0       = STI_GDP | STI_ID_0,
+	STI_GDP_1       = STI_GDP | STI_ID_1,
+	STI_GDP_2       = STI_GDP | STI_ID_2,
+	STI_GDP_3       = STI_GDP | STI_ID_3,
+	STI_VID_0       = STI_VID | STI_ID_0,
+	STI_VID_1       = STI_VID | STI_ID_1,
+	STI_CURSOR      = STI_CUR,
+	STI_BACK        = STI_BCK
+};
+
+/**
+ * STI layer functions structure
+ *
+ * @get_formats:	get layer supported formats
+ * @get_nb_formats:	get number of format supported
+ * @init:               initialize the layer
+ * @prepare:		prepare layer before rendering
+ * @commit:		set layer for rendering
+ * @disable:		disable layer
+ */
+struct sti_layer_funcs {
+	const uint32_t* (*get_formats)(struct sti_layer *layer);
+	unsigned int (*get_nb_formats)(struct sti_layer *layer);
+	void (*init)(struct sti_layer *layer);
+	int (*prepare)(struct sti_layer *layer, bool first_prepare);
+	int (*commit)(struct sti_layer *layer);
+	int (*disable)(struct sti_layer *layer);
+};
+
+/**
+ * STI layer structure
+ *
+ * @plane:              drm plane it is bound to (if any)
+ * @fb:                 drm fb it is bound to
+ * @mode:               display mode
+ * @desc:               layer type & id
+ * @device:		driver device
+ * @regs:		layer registers
+ * @ops:                layer functions
+ * @zorder:             layer z-order
+ * @mixer_id:           id of the mixer used to display the layer
+ * @enabled:            to know if the layer is active or not
+ * @src_x src_y:        coordinates of the input (fb) area
+ * @src_w src_h:        size of the input (fb) area
+ * @dst_x dst_y:        coordinates of the output (crtc) area
+ * @dst_w dst_h:        size of the output (crtc) area
+ * @format:             format
+ * @pitches:            pitch of 'planes' (eg: Y, U, V)
+ * @offsets:            offset of 'planes'
+ * @paddr:              physical address of the input buffer
+ */
+struct sti_layer {
+	struct drm_plane plane;
+	struct drm_framebuffer *fb;
+	struct drm_display_mode *mode;
+	enum sti_layer_desc desc;
+	struct device *dev;
+	void __iomem *regs;
+	const struct sti_layer_funcs *ops;
+	int zorder;
+	int mixer_id;
+	bool enabled;
+	int src_x, src_y;
+	int src_w, src_h;
+	int dst_x, dst_y;
+	int dst_w, dst_h;
+	uint32_t format;
+	unsigned int pitches[4];
+	unsigned int offsets[4];
+	dma_addr_t paddr;
+};
+
+struct sti_layer *sti_layer_create(struct device *dev, int desc,
+			void __iomem *baseaddr);
+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 sti_layer_commit(struct sti_layer *layer);
+int sti_layer_disable(struct sti_layer *layer);
+const uint32_t *sti_layer_get_formats(struct sti_layer *layer);
+unsigned int sti_layer_get_nb_formats(struct sti_layer *layer);
+const char *sti_layer_to_str(struct sti_layer *layer);
+
+#endif