1 files changed, 602 insertions, 0 deletions

diff --git a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
new file mode 100644
index 00000000000..5dd3c7d031d
--- /dev/null
+++ b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
@@ -0,0 +1,602 @@
+/*
+ * Copyright (C) 2012 Texas Instruments
+ * Author: Rob Clark <robdclark@gmail.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 <linux/kfifo.h>
+
+#include "tilcdc_drv.h"
+#include "tilcdc_regs.h"
+
+struct tilcdc_crtc {
+	struct drm_crtc base;
+
+	const struct tilcdc_panel_info *info;
+	uint32_t dirty;
+	dma_addr_t start, end;
+	struct drm_pending_vblank_event *event;
+	int dpms;
+	wait_queue_head_t frame_done_wq;
+	bool frame_done;
+
+	/* fb currently set to scanout 0/1: */
+	struct drm_framebuffer *scanout[2];
+
+	/* for deferred fb unref's: */
+	DECLARE_KFIFO_PTR(unref_fifo, struct drm_framebuffer *);
+	struct work_struct work;
+};
+#define to_tilcdc_crtc(x) container_of(x, struct tilcdc_crtc, base)
+
+static void unref_worker(struct work_struct *work)
+{
+	struct tilcdc_crtc *tilcdc_crtc = container_of(work, struct tilcdc_crtc, work);
+	struct drm_device *dev = tilcdc_crtc->base.dev;
+	struct drm_framebuffer *fb;
+
+	mutex_lock(&dev->mode_config.mutex);
+	while (kfifo_get(&tilcdc_crtc->unref_fifo, &fb))
+		drm_framebuffer_unreference(fb);
+	mutex_unlock(&dev->mode_config.mutex);
+}
+
+static void set_scanout(struct drm_crtc *crtc, int n)
+{
+	static const uint32_t base_reg[] = {
+			LCDC_DMA_FB_BASE_ADDR_0_REG, LCDC_DMA_FB_BASE_ADDR_1_REG,
+	};
+	static const uint32_t ceil_reg[] = {
+			LCDC_DMA_FB_CEILING_ADDR_0_REG, LCDC_DMA_FB_CEILING_ADDR_1_REG,
+	};
+	static const uint32_t stat[] = {
+			LCDC_END_OF_FRAME0, LCDC_END_OF_FRAME1,
+	};
+	struct tilcdc_crtc *tilcdc_crtc = to_tilcdc_crtc(crtc);
+	struct drm_device *dev = crtc->dev;
+
+	pm_runtime_get_sync(dev->dev);
+	tilcdc_write(dev, base_reg[n], tilcdc_crtc->start);
+	tilcdc_write(dev, ceil_reg[n], tilcdc_crtc->end);
+	if (tilcdc_crtc->scanout[n]) {
+		if (kfifo_put(&tilcdc_crtc->unref_fifo,
+				(const struct drm_framebuffer **)&tilcdc_crtc->scanout[n])) {
+			struct tilcdc_drm_private *priv = dev->dev_private;
+			queue_work(priv->wq, &tilcdc_crtc->work);
+		} else {
+			dev_err(dev->dev, "unref fifo full!\n");
+			drm_framebuffer_unreference(tilcdc_crtc->scanout[n]);
+		}
+	}
+	tilcdc_crtc->scanout[n] = crtc->fb;
+	drm_framebuffer_reference(tilcdc_crtc->scanout[n]);
+	tilcdc_crtc->dirty &= ~stat[n];
+	pm_runtime_put_sync(dev->dev);
+}
+
+static void update_scanout(struct drm_crtc *crtc)
+{
+	struct tilcdc_crtc *tilcdc_crtc = to_tilcdc_crtc(crtc);
+	struct drm_device *dev = crtc->dev;
+	struct drm_framebuffer *fb = crtc->fb;
+	struct drm_gem_cma_object *gem;
+	unsigned int depth, bpp;
+
+	drm_fb_get_bpp_depth(fb->pixel_format, &depth, &bpp);
+	gem = drm_fb_cma_get_gem_obj(fb, 0);
+
+	tilcdc_crtc->start = gem->paddr + fb->offsets[0] +
+			(crtc->y * fb->pitches[0]) + (crtc->x * bpp/8);
+
+	tilcdc_crtc->end = tilcdc_crtc->start +
+			(crtc->mode.vdisplay * fb->pitches[0]);
+
+	if (tilcdc_crtc->dpms == DRM_MODE_DPMS_ON) {
+		/* already enabled, so just mark the frames that need
+		 * updating and they will be updated on vblank:
+		 */
+		tilcdc_crtc->dirty |= LCDC_END_OF_FRAME0 | LCDC_END_OF_FRAME1;
+		drm_vblank_get(dev, 0);
+	} else {
+		/* not enabled yet, so update registers immediately: */
+		set_scanout(crtc, 0);
+		set_scanout(crtc, 1);
+	}
+}
+
+static void start(struct drm_crtc *crtc)
+{
+	struct drm_device *dev = crtc->dev;
+	struct tilcdc_drm_private *priv = dev->dev_private;
+
+	if (priv->rev == 2) {
+		tilcdc_set(dev, LCDC_CLK_RESET_REG, LCDC_CLK_MAIN_RESET);
+		msleep(1);
+		tilcdc_clear(dev, LCDC_CLK_RESET_REG, LCDC_CLK_MAIN_RESET);
+		msleep(1);
+	}
+
+	tilcdc_set(dev, LCDC_DMA_CTRL_REG, LCDC_DUAL_FRAME_BUFFER_ENABLE);
+	tilcdc_set(dev, LCDC_RASTER_CTRL_REG, LCDC_PALETTE_LOAD_MODE(DATA_ONLY));
+	tilcdc_set(dev, LCDC_RASTER_CTRL_REG, LCDC_RASTER_ENABLE);
+}
+
+static void stop(struct drm_crtc *crtc)
+{
+	struct drm_device *dev = crtc->dev;
+
+	tilcdc_clear(dev, LCDC_RASTER_CTRL_REG, LCDC_RASTER_ENABLE);
+}
+
+static void tilcdc_crtc_destroy(struct drm_crtc *crtc)
+{
+	struct tilcdc_crtc *tilcdc_crtc = to_tilcdc_crtc(crtc);
+
+	WARN_ON(tilcdc_crtc->dpms == DRM_MODE_DPMS_ON);
+
+	drm_crtc_cleanup(crtc);
+	WARN_ON(!kfifo_is_empty(&tilcdc_crtc->unref_fifo));
+	kfifo_free(&tilcdc_crtc->unref_fifo);
+	kfree(tilcdc_crtc);
+}
+
+static int tilcdc_crtc_page_flip(struct drm_crtc *crtc,
+		struct drm_framebuffer *fb,
+		struct drm_pending_vblank_event *event)
+{
+	struct tilcdc_crtc *tilcdc_crtc = to_tilcdc_crtc(crtc);
+	struct drm_device *dev = crtc->dev;
+
+	if (tilcdc_crtc->event) {
+		dev_err(dev->dev, "already pending page flip!\n");
+		return -EBUSY;
+	}
+
+	crtc->fb = fb;
+	tilcdc_crtc->event = event;
+	update_scanout(crtc);
+
+	return 0;
+}
+
+static void tilcdc_crtc_dpms(struct drm_crtc *crtc, int mode)
+{
+	struct tilcdc_crtc *tilcdc_crtc = to_tilcdc_crtc(crtc);
+	struct drm_device *dev = crtc->dev;
+	struct tilcdc_drm_private *priv = dev->dev_private;
+
+	/* we really only care about on or off: */
+	if (mode != DRM_MODE_DPMS_ON)
+		mode = DRM_MODE_DPMS_OFF;
+
+	if (tilcdc_crtc->dpms == mode)
+		return;
+
+	tilcdc_crtc->dpms = mode;
+
+	pm_runtime_get_sync(dev->dev);
+
+	if (mode == DRM_MODE_DPMS_ON) {
+		pm_runtime_forbid(dev->dev);
+		start(crtc);
+	} else {
+		tilcdc_crtc->frame_done = false;
+		stop(crtc);
+
+		/* if necessary wait for framedone irq which will still come
+		 * before putting things to sleep..
+		 */
+		if (priv->rev == 2) {
+			int ret = wait_event_timeout(
+					tilcdc_crtc->frame_done_wq,
+					tilcdc_crtc->frame_done,
+					msecs_to_jiffies(50));
+			if (ret == 0)
+				dev_err(dev->dev, "timeout waiting for framedone\n");
+		}
+		pm_runtime_allow(dev->dev);
+	}
+
+	pm_runtime_put_sync(dev->dev);
+}
+
+static bool tilcdc_crtc_mode_fixup(struct drm_crtc *crtc,
+		const struct drm_display_mode *mode,
+		struct drm_display_mode *adjusted_mode)
+{
+	return true;
+}
+
+static void tilcdc_crtc_prepare(struct drm_crtc *crtc)
+{
+	tilcdc_crtc_dpms(crtc, DRM_MODE_DPMS_OFF);
+}
+
+static void tilcdc_crtc_commit(struct drm_crtc *crtc)
+{
+	tilcdc_crtc_dpms(crtc, DRM_MODE_DPMS_ON);
+}
+
+static int tilcdc_crtc_mode_set(struct drm_crtc *crtc,
+		struct drm_display_mode *mode,
+		struct drm_display_mode *adjusted_mode,
+		int x, int y,
+		struct drm_framebuffer *old_fb)
+{
+	struct tilcdc_crtc *tilcdc_crtc = to_tilcdc_crtc(crtc);
+	struct drm_device *dev = crtc->dev;
+	struct tilcdc_drm_private *priv = dev->dev_private;
+	const struct tilcdc_panel_info *info = tilcdc_crtc->info;
+	uint32_t reg, hbp, hfp, hsw, vbp, vfp, vsw;
+	int ret;
+
+	ret = tilcdc_crtc_mode_valid(crtc, mode);
+	if (WARN_ON(ret))
+		return ret;
+
+	if (WARN_ON(!info))
+		return -EINVAL;
+
+	pm_runtime_get_sync(dev->dev);
+
+	/* Configure the Burst Size and fifo threshold of DMA: */
+	reg = tilcdc_read(dev, LCDC_DMA_CTRL_REG) & ~0x00000770;
+	switch (info->dma_burst_sz) {
+	case 1:
+		reg |= LCDC_DMA_BURST_SIZE(LCDC_DMA_BURST_1);
+		break;
+	case 2:
+		reg |= LCDC_DMA_BURST_SIZE(LCDC_DMA_BURST_2);
+		break;
+	case 4:
+		reg |= LCDC_DMA_BURST_SIZE(LCDC_DMA_BURST_4);
+		break;
+	case 8:
+		reg |= LCDC_DMA_BURST_SIZE(LCDC_DMA_BURST_8);
+		break;
+	case 16:
+		reg |= LCDC_DMA_BURST_SIZE(LCDC_DMA_BURST_16);
+		break;
+	default:
+		return -EINVAL;
+	}
+	reg |= (info->fifo_th << 8);
+	tilcdc_write(dev, LCDC_DMA_CTRL_REG, reg);
+
+	/* Configure timings: */
+	hbp = mode->htotal - mode->hsync_end;
+	hfp = mode->hsync_start - mode->hdisplay;
+	hsw = mode->hsync_end - mode->hsync_start;
+	vbp = mode->vtotal - mode->vsync_end;
+	vfp = mode->vsync_start - mode->vdisplay;
+	vsw = mode->vsync_end - mode->vsync_start;
+
+	DBG("%dx%d, hbp=%u, hfp=%u, hsw=%u, vbp=%u, vfp=%u, vsw=%u",
+			mode->hdisplay, mode->vdisplay, hbp, hfp, hsw, vbp, vfp, vsw);
+
+	/* Configure the AC Bias Period and Number of Transitions per Interrupt: */
+	reg = tilcdc_read(dev, LCDC_RASTER_TIMING_2_REG) & ~0x000fff00;
+	reg |= LCDC_AC_BIAS_FREQUENCY(info->ac_bias) |
+		LCDC_AC_BIAS_TRANSITIONS_PER_INT(info->ac_bias_intrpt);
+	if (priv->rev == 2) {
+		reg |= (hfp & 0x300) >> 8;
+		reg |= (hbp & 0x300) >> 4;
+		reg |= (hsw & 0x3c0) << 21;
+	}
+	tilcdc_write(dev, LCDC_RASTER_TIMING_2_REG, reg);
+
+	reg = (((mode->hdisplay >> 4) - 1) << 4) |
+		((hbp & 0xff) << 24) |
+		((hfp & 0xff) << 16) |
+		((hsw & 0x3f) << 10);
+	if (priv->rev == 2)
+		reg |= (((mode->hdisplay >> 4) - 1) & 0x40) >> 3;
+	tilcdc_write(dev, LCDC_RASTER_TIMING_0_REG, reg);
+
+	reg = ((mode->vdisplay - 1) & 0x3ff) |
+		((vbp & 0xff) << 24) |
+		((vfp & 0xff) << 16) |
+		((vsw & 0x3f) << 10);
+	tilcdc_write(dev, LCDC_RASTER_TIMING_1_REG, reg);
+
+	/* Configure display type: */
+	reg = tilcdc_read(dev, LCDC_RASTER_CTRL_REG) &
+		~(LCDC_TFT_MODE | LCDC_MONO_8BIT_MODE | LCDC_MONOCHROME_MODE |
+			LCDC_V2_TFT_24BPP_MODE | LCDC_V2_TFT_24BPP_UNPACK | 0x000ff000);
+	reg |= LCDC_TFT_MODE; /* no monochrome/passive support */
+	if (info->tft_alt_mode)
+		reg |= LCDC_TFT_ALT_ENABLE;
+	if (priv->rev == 2) {
+		unsigned int depth, bpp;
+
+		drm_fb_get_bpp_depth(crtc->fb->pixel_format, &depth, &bpp);
+		switch (bpp) {
+		case 16:
+			break;
+		case 32:
+			reg |= LCDC_V2_TFT_24BPP_UNPACK;
+			/* fallthrough */
+		case 24:
+			reg |= LCDC_V2_TFT_24BPP_MODE;
+			break;
+		default:
+			dev_err(dev->dev, "invalid pixel format\n");
+			return -EINVAL;
+		}
+	}
+	reg |= info->fdd < 12;
+	tilcdc_write(dev, LCDC_RASTER_CTRL_REG, reg);
+
+	if (info->invert_pxl_clk)
+		tilcdc_set(dev, LCDC_RASTER_TIMING_2_REG, LCDC_INVERT_PIXEL_CLOCK);
+	else
+		tilcdc_clear(dev, LCDC_RASTER_TIMING_2_REG, LCDC_INVERT_PIXEL_CLOCK);
+
+	if (info->sync_ctrl)
+		tilcdc_set(dev, LCDC_RASTER_TIMING_2_REG, LCDC_SYNC_CTRL);
+	else
+		tilcdc_clear(dev, LCDC_RASTER_TIMING_2_REG, LCDC_SYNC_CTRL);
+
+	if (info->sync_edge)
+		tilcdc_set(dev, LCDC_RASTER_TIMING_2_REG, LCDC_SYNC_EDGE);
+	else
+		tilcdc_clear(dev, LCDC_RASTER_TIMING_2_REG, LCDC_SYNC_EDGE);
+
+	if (mode->flags & DRM_MODE_FLAG_NHSYNC)
+		tilcdc_set(dev, LCDC_RASTER_TIMING_2_REG, LCDC_INVERT_HSYNC);
+	else
+		tilcdc_clear(dev, LCDC_RASTER_TIMING_2_REG, LCDC_INVERT_HSYNC);
+
+	if (mode->flags & DRM_MODE_FLAG_NVSYNC)
+		tilcdc_set(dev, LCDC_RASTER_TIMING_2_REG, LCDC_INVERT_VSYNC);
+	else
+		tilcdc_clear(dev, LCDC_RASTER_TIMING_2_REG, LCDC_INVERT_VSYNC);
+
+	if (info->raster_order)
+		tilcdc_set(dev, LCDC_RASTER_CTRL_REG, LCDC_RASTER_ORDER);
+	else
+		tilcdc_clear(dev, LCDC_RASTER_CTRL_REG, LCDC_RASTER_ORDER);
+
+
+	update_scanout(crtc);
+	tilcdc_crtc_update_clk(crtc);
+
+	pm_runtime_put_sync(dev->dev);
+
+	return 0;
+}
+
+static int tilcdc_crtc_mode_set_base(struct drm_crtc *crtc, int x, int y,
+		struct drm_framebuffer *old_fb)
+{
+	update_scanout(crtc);
+	return 0;
+}
+
+static void tilcdc_crtc_load_lut(struct drm_crtc *crtc)
+{
+}
+
+static const struct drm_crtc_funcs tilcdc_crtc_funcs = {
+		.destroy        = tilcdc_crtc_destroy,
+		.set_config     = drm_crtc_helper_set_config,
+		.page_flip      = tilcdc_crtc_page_flip,
+};
+
+static const struct drm_crtc_helper_funcs tilcdc_crtc_helper_funcs = {
+		.dpms           = tilcdc_crtc_dpms,
+		.mode_fixup     = tilcdc_crtc_mode_fixup,
+		.prepare        = tilcdc_crtc_prepare,
+		.commit         = tilcdc_crtc_commit,
+		.mode_set       = tilcdc_crtc_mode_set,
+		.mode_set_base  = tilcdc_crtc_mode_set_base,
+		.load_lut       = tilcdc_crtc_load_lut,
+};
+
+int tilcdc_crtc_max_width(struct drm_crtc *crtc)
+{
+	struct drm_device *dev = crtc->dev;
+	struct tilcdc_drm_private *priv = dev->dev_private;
+	int max_width = 0;
+
+	if (priv->rev == 1)
+		max_width = 1024;
+	else if (priv->rev == 2)
+		max_width = 2048;
+
+	return max_width;
+}
+
+int tilcdc_crtc_mode_valid(struct drm_crtc *crtc, struct drm_display_mode *mode)
+{
+	struct tilcdc_drm_private *priv = crtc->dev->dev_private;
+	unsigned int bandwidth;
+
+	if (mode->hdisplay > tilcdc_crtc_max_width(crtc))
+		return MODE_VIRTUAL_X;
+
+	/* width must be multiple of 16 */
+	if (mode->hdisplay & 0xf)
+		return MODE_VIRTUAL_X;
+
+	if (mode->vdisplay > 2048)
+		return MODE_VIRTUAL_Y;
+
+	/* filter out modes that would require too much memory bandwidth: */
+	bandwidth = mode->hdisplay * mode->vdisplay * drm_mode_vrefresh(mode);
+	if (bandwidth > priv->max_bandwidth)
+		return MODE_BAD;
+
+	return MODE_OK;
+}
+
+void tilcdc_crtc_set_panel_info(struct drm_crtc *crtc,
+		const struct tilcdc_panel_info *info)
+{
+	struct tilcdc_crtc *tilcdc_crtc = to_tilcdc_crtc(crtc);
+	tilcdc_crtc->info = info;
+}
+
+void tilcdc_crtc_update_clk(struct drm_crtc *crtc)
+{
+	struct tilcdc_crtc *tilcdc_crtc = to_tilcdc_crtc(crtc);
+	struct drm_device *dev = crtc->dev;
+	struct tilcdc_drm_private *priv = dev->dev_private;
+	int dpms = tilcdc_crtc->dpms;
+	unsigned int lcd_clk, div;
+	int ret;
+
+	pm_runtime_get_sync(dev->dev);
+
+	if (dpms == DRM_MODE_DPMS_ON)
+		tilcdc_crtc_dpms(crtc, DRM_MODE_DPMS_OFF);
+
+	/* in raster mode, minimum divisor is 2: */
+	ret = clk_set_rate(priv->disp_clk, crtc->mode.clock * 1000 * 2);
+	if (ret) {
+		dev_err(dev->dev, "failed to set display clock rate to: %d\n",
+				crtc->mode.clock);
+		goto out;
+	}
+
+	lcd_clk = clk_get_rate(priv->clk);
+	div = lcd_clk / (crtc->mode.clock * 1000);
+
+	DBG("lcd_clk=%u, mode clock=%d, div=%u", lcd_clk, crtc->mode.clock, div);
+	DBG("fck=%lu, dpll_disp_ck=%lu", clk_get_rate(priv->clk), clk_get_rate(priv->disp_clk));
+
+	/* Configure the LCD clock divisor. */
+	tilcdc_write(dev, LCDC_CTRL_REG, LCDC_CLK_DIVISOR(div) |
+			LCDC_RASTER_MODE);
+
+	if (priv->rev == 2)
+		tilcdc_set(dev, LCDC_CLK_ENABLE_REG,
+				LCDC_V2_DMA_CLK_EN | LCDC_V2_LIDD_CLK_EN |
+				LCDC_V2_CORE_CLK_EN);
+
+	if (dpms == DRM_MODE_DPMS_ON)
+		tilcdc_crtc_dpms(crtc, DRM_MODE_DPMS_ON);
+
+out:
+	pm_runtime_put_sync(dev->dev);
+}
+
+irqreturn_t tilcdc_crtc_irq(struct drm_crtc *crtc)
+{
+	struct tilcdc_crtc *tilcdc_crtc = to_tilcdc_crtc(crtc);
+	struct drm_device *dev = crtc->dev;
+	struct tilcdc_drm_private *priv = dev->dev_private;
+	uint32_t stat = tilcdc_read_irqstatus(dev);
+
+	if ((stat & LCDC_SYNC_LOST) && (stat & LCDC_FIFO_UNDERFLOW)) {
+		stop(crtc);
+		dev_err(dev->dev, "error: %08x\n", stat);
+		tilcdc_clear_irqstatus(dev, stat);
+		start(crtc);
+	} else if (stat & LCDC_PL_LOAD_DONE) {
+		tilcdc_clear_irqstatus(dev, stat);
+	} else {
+		struct drm_pending_vblank_event *event;
+		unsigned long flags;
+		uint32_t dirty = tilcdc_crtc->dirty & stat;
+
+		tilcdc_clear_irqstatus(dev, stat);
+
+		if (dirty & LCDC_END_OF_FRAME0)
+			set_scanout(crtc, 0);
+
+		if (dirty & LCDC_END_OF_FRAME1)
+			set_scanout(crtc, 1);
+
+		drm_handle_vblank(dev, 0);
+
+		spin_lock_irqsave(&dev->event_lock, flags);
+		event = tilcdc_crtc->event;
+		tilcdc_crtc->event = NULL;
+		if (event)
+			drm_send_vblank_event(dev, 0, event);
+		spin_unlock_irqrestore(&dev->event_lock, flags);
+
+		if (dirty && !tilcdc_crtc->dirty)
+			drm_vblank_put(dev, 0);
+	}
+
+	if (priv->rev == 2) {
+		if (stat & LCDC_FRAME_DONE) {
+			tilcdc_crtc->frame_done = true;
+			wake_up(&tilcdc_crtc->frame_done_wq);
+		}
+		tilcdc_write(dev, LCDC_END_OF_INT_IND_REG, 0);
+	}
+
+	return IRQ_HANDLED;
+}
+
+void tilcdc_crtc_cancel_page_flip(struct drm_crtc *crtc, struct drm_file *file)
+{
+	struct tilcdc_crtc *tilcdc_crtc = to_tilcdc_crtc(crtc);
+	struct drm_pending_vblank_event *event;
+	struct drm_device *dev = crtc->dev;
+	unsigned long flags;
+
+	/* Destroy the pending vertical blanking event associated with the
+	 * pending page flip, if any, and disable vertical blanking interrupts.
+	 */
+	spin_lock_irqsave(&dev->event_lock, flags);
+	event = tilcdc_crtc->event;
+	if (event && event->base.file_priv == file) {
+		tilcdc_crtc->event = NULL;
+		event->base.destroy(&event->base);
+		drm_vblank_put(dev, 0);
+	}
+	spin_unlock_irqrestore(&dev->event_lock, flags);
+}
+
+struct drm_crtc *tilcdc_crtc_create(struct drm_device *dev)
+{
+	struct tilcdc_crtc *tilcdc_crtc;
+	struct drm_crtc *crtc;
+	int ret;
+
+	tilcdc_crtc = kzalloc(sizeof(*tilcdc_crtc), GFP_KERNEL);
+	if (!tilcdc_crtc) {
+		dev_err(dev->dev, "allocation failed\n");
+		return NULL;
+	}
+
+	crtc = &tilcdc_crtc->base;
+
+	tilcdc_crtc->dpms = DRM_MODE_DPMS_OFF;
+	init_waitqueue_head(&tilcdc_crtc->frame_done_wq);
+
+	ret = kfifo_alloc(&tilcdc_crtc->unref_fifo, 16, GFP_KERNEL);
+	if (ret) {
+		dev_err(dev->dev, "could not allocate unref FIFO\n");
+		goto fail;
+	}
+
+	INIT_WORK(&tilcdc_crtc->work, unref_worker);
+
+	ret = drm_crtc_init(dev, crtc, &tilcdc_crtc_funcs);
+	if (ret < 0)
+		goto fail;
+
+	drm_crtc_helper_add(crtc, &tilcdc_crtc_helper_funcs);
+
+	return crtc;
+
+fail:
+	tilcdc_crtc_destroy(crtc);
+	return NULL;
+}