drm/tilcdc: Add dummy primary plane implementation

Add dummy primary plane implementation. LCDC does not really have
planes, only simple framebuffer that is mandatory. This primary plane
implementation has the necessary checks for implementing simple
framebuffer trough DRM plane abstraction. For setting the actual
framebuffer the implementation relies on a CRTC side function.
Signed-off-by: Jyri Sarha <jsarha@ti.com>

drivers/gpu/drm/tilcdc/Makefile

@@ -7,6 +7,7 @@ obj-$(CONFIG_DRM_TILCDC_SLAVE_COMPAT) += tilcdc_slave_compat.o \
 					 tilcdc_slave_compat.dtb.o
 
 tilcdc-y := \
+	tilcdc_plane.o \
 	tilcdc_crtc.o \
 	tilcdc_tfp410.o \
 	tilcdc_panel.o \

drivers/gpu/drm/tilcdc/tilcdc_drv.h

@@ -179,4 +179,6 @@ int tilcdc_crtc_page_flip(struct drm_crtc *crtc,
 		struct drm_pending_vblank_event *event,
 		uint32_t page_flip_flags);
 
+int tilcdc_plane_init(struct drm_device *dev, struct drm_plane *plane);
+
 #endif /* __TILCDC_DRV_H__ */

drivers/gpu/drm/tilcdc/tilcdc_plane.c

+/*
+ * Copyright (C) 2015 Texas Instruments
+ * Author: Jyri Sarha <jsarha@ti.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <drm/drmP.h>
+
+#include <drm/drm_atomic.h>
+#include <drm/drm_plane_helper.h>
+#include <drm/drm_atomic_helper.h>
+#include <uapi/drm/drm_fourcc.h>
+
+#include "tilcdc_drv.h"
+
+static const u32 tilcdc_formats[] = { DRM_FORMAT_RGB565,
+				      DRM_FORMAT_RGB888,
+				      DRM_FORMAT_XRGB8888 };
+
+static struct drm_plane_funcs tilcdc_plane_funcs = {
+	.update_plane	= drm_atomic_helper_update_plane,
+	.disable_plane	= drm_atomic_helper_disable_plane,
+	.destroy	= drm_plane_cleanup,
+	.set_property	= drm_atomic_helper_plane_set_property,
+	.reset		= drm_atomic_helper_plane_reset,
+	.atomic_duplicate_state = drm_atomic_helper_plane_duplicate_state,
+	.atomic_destroy_state = drm_atomic_helper_plane_destroy_state,
+};
+
+static int tilcdc_plane_atomic_check(struct drm_plane *plane,
+				     struct drm_plane_state *state)
+{
+	struct drm_crtc_state *crtc_state;
+	struct drm_plane_state *old_state = plane->state;
+	unsigned int depth, bpp;
+
+	if (!state->crtc)
+		return 0;
+
+	if (WARN_ON(!state->fb))
+		return -EINVAL;
+
+	if (state->crtc_x || state->crtc_y) {
+		dev_err(plane->dev->dev, "%s: crtc position must be zero.",
+			__func__);
+		return -EINVAL;
+	}
+
+	crtc_state = drm_atomic_get_existing_crtc_state(state->state,
+							state->crtc);
+	/* we should have a crtc state if the plane is attached to a crtc */
+	if (WARN_ON(!crtc_state))
+		return 0;
+
+	if (crtc_state->mode.hdisplay != state->crtc_w ||
+	    crtc_state->mode.vdisplay != state->crtc_h) {
+		dev_err(plane->dev->dev,
+			"%s: Size must match mode (%dx%d == %dx%d)", __func__,
+			crtc_state->mode.hdisplay, crtc_state->mode.vdisplay,
+			state->crtc_w, state->crtc_h);
+		return -EINVAL;
+	}
+
+	drm_fb_get_bpp_depth(state->fb->pixel_format, &depth, &bpp);
+	if (state->fb->pitches[0] != crtc_state->mode.hdisplay * bpp / 8) {
+		dev_err(plane->dev->dev,
+			"Invalid pitch: fb and crtc widths must be the same");
+		return -EINVAL;
+	}
+
+	if (state->fb && old_state->fb &&
+	    state->fb->pixel_format != old_state->fb->pixel_format) {
+		dev_dbg(plane->dev->dev,
+			"%s(): pixel format change requires mode_change\n",
+			__func__);
+		crtc_state->mode_changed = true;
+	}
+
+	return 0;
+}
+
+static void tilcdc_plane_atomic_update(struct drm_plane *plane,
+				       struct drm_plane_state *old_state)
+{
+	struct drm_plane_state *state = plane->state;
+
+	if (!state->crtc)
+		return;
+
+	if (WARN_ON(!state->fb || !state->crtc->state))
+		return;
+
+	tilcdc_crtc_page_flip(state->crtc,
+			      state->fb,
+			      state->crtc->state->event,
+			      0);
+}
+
+static const struct drm_plane_helper_funcs plane_helper_funcs = {
+	.atomic_check = tilcdc_plane_atomic_check,
+	.atomic_update = tilcdc_plane_atomic_update,
+};
+
+int tilcdc_plane_init(struct drm_device *dev,
+		      struct drm_plane *plane)
+{
+	int ret;
+
+	ret = drm_plane_init(dev, plane, 1,
+			     &tilcdc_plane_funcs,
+			     tilcdc_formats,
+			     ARRAY_SIZE(tilcdc_formats),
+			     true);
+	if (ret) {
+		dev_err(dev->dev, "Failed to initialize plane: %d\n", ret);
+		return ret;
+	}
+
+	drm_plane_helper_add(plane, &plane_helper_funcs);
+
+	return 0;
+}