drivers/gpu/drm/omapdrm/omap_fbdev.c - kernel/msm-4.19 - Gitiles

 /*
  * drivers/gpu/drm/omapdrm/omap_fbdev.c
  *
  * Copyright (C) 2011 Texas Instruments
  * Author: Rob Clark <rob@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 "omap_drv.h"

 #include "drm_crtc.h"
 #include "drm_fb_helper.h"

 MODULE_PARM_DESC(ywrap, "Enable ywrap scrolling (omap44xx and later, default 'y')");
 static bool ywrap_enabled = true;
 module_param_named(ywrap, ywrap_enabled, bool, 0644);

 /*
  * fbdev funcs, to implement legacy fbdev interface on top of drm driver
  */

 #define to_omap_fbdev(x) container_of(x, struct omap_fbdev, base)

 struct omap_fbdev {
 	struct drm_fb_helper base;
 	struct drm_framebuffer *fb;
 	struct drm_gem_object *bo;
 	bool ywrap_enabled;

 	/* for deferred dmm roll when getting called in atomic ctx */
 	struct work_struct work;
 };

 static void omap_fbdev_flush(struct fb_info *fbi, int x, int y, int w, int h);
 static struct drm_fb_helper *get_fb(struct fb_info *fbi);

 static ssize_t omap_fbdev_write(struct fb_info *fbi, const char __user *buf,
 		size_t count, loff_t *ppos)
 {
 	ssize_t res;

 	res = fb_sys_write(fbi, buf, count, ppos);
 	omap_fbdev_flush(fbi, 0, 0, fbi->var.xres, fbi->var.yres);

 	return res;
 }

 static void omap_fbdev_fillrect(struct fb_info *fbi,
 		const struct fb_fillrect *rect)
 {
 	sys_fillrect(fbi, rect);
 	omap_fbdev_flush(fbi, rect->dx, rect->dy, rect->width, rect->height);
 }

 static void omap_fbdev_copyarea(struct fb_info *fbi,
 		const struct fb_copyarea *area)
 {
 	sys_copyarea(fbi, area);
 	omap_fbdev_flush(fbi, area->dx, area->dy, area->width, area->height);
 }

 static void omap_fbdev_imageblit(struct fb_info *fbi,
 		const struct fb_image *image)
 {
 	sys_imageblit(fbi, image);
 	omap_fbdev_flush(fbi, image->dx, image->dy,
 				image->width, image->height);
 }

 static void pan_worker(struct work_struct *work)
 {
 	struct omap_fbdev *fbdev = container_of(work, struct omap_fbdev, work);
 	struct fb_info *fbi = fbdev->base.fbdev;
 	int npages;

 	/* DMM roll shifts in 4K pages: */
 	npages = fbi->fix.line_length >> PAGE_SHIFT;
 	omap_gem_roll(fbdev->bo, fbi->var.yoffset * npages);
 }

 static int omap_fbdev_pan_display(struct fb_var_screeninfo *var,
 		struct fb_info *fbi)
 {
 	struct drm_fb_helper *helper = get_fb(fbi);
 	struct omap_fbdev *fbdev = to_omap_fbdev(helper);

 	if (!helper)
 		goto fallback;

 	if (!fbdev->ywrap_enabled)
 		goto fallback;

 	if (drm_can_sleep()) {
 		pan_worker(&fbdev->work);
 	} else {
 		struct omap_drm_private *priv = helper->dev->dev_private;
 		queue_work(priv->wq, &fbdev->work);
 	}

 	return 0;

 fallback:
 	return drm_fb_helper_pan_display(var, fbi);
 }

 static struct fb_ops omap_fb_ops = {
 	.owner = THIS_MODULE,

 	/* Note: to properly handle manual update displays, we wrap the
 	 * basic fbdev ops which write to the framebuffer
 	 */
 	.fb_read = fb_sys_read,
 	.fb_write = omap_fbdev_write,
 	.fb_fillrect = omap_fbdev_fillrect,
 	.fb_copyarea = omap_fbdev_copyarea,
 	.fb_imageblit = omap_fbdev_imageblit,

 	.fb_check_var = drm_fb_helper_check_var,
 	.fb_set_par = drm_fb_helper_set_par,
 	.fb_pan_display = omap_fbdev_pan_display,
 	.fb_blank = drm_fb_helper_blank,
 	.fb_setcmap = drm_fb_helper_setcmap,
 };

 static int omap_fbdev_create(struct drm_fb_helper *helper,
 		struct drm_fb_helper_surface_size *sizes)
 {
 	struct omap_fbdev *fbdev = to_omap_fbdev(helper);
 	struct drm_device *dev = helper->dev;
 	struct omap_drm_private *priv = dev->dev_private;
 	struct drm_framebuffer *fb = NULL;
 	union omap_gem_size gsize;
 	struct fb_info *fbi = NULL;
 	struct drm_mode_fb_cmd2 mode_cmd = {0};
 	dma_addr_t paddr;
 	int ret;

 	/* only doing ARGB32 since this is what is needed to alpha-blend
 	 * with video overlays:
 	 */
 	sizes->surface_bpp = 32;
 	sizes->surface_depth = 32;

 	DBG("create fbdev: %dx%d@%d (%dx%d)", sizes->surface_width,
 			sizes->surface_height, sizes->surface_bpp,
 			sizes->fb_width, sizes->fb_height);

 	mode_cmd.pixel_format = drm_mode_legacy_fb_format(sizes->surface_bpp,
 			sizes->surface_depth);

 	mode_cmd.width = sizes->surface_width;
 	mode_cmd.height = sizes->surface_height;

 	mode_cmd.pitches[0] = align_pitch(
 			mode_cmd.width * ((sizes->surface_bpp + 7) / 8),
 			mode_cmd.width, sizes->surface_bpp);

 	fbdev->ywrap_enabled = priv->has_dmm && ywrap_enabled;
 	if (fbdev->ywrap_enabled) {
 		/* need to align pitch to page size if using DMM scrolling */
 		mode_cmd.pitches[0] = ALIGN(mode_cmd.pitches[0], PAGE_SIZE);
 	}

 	/* allocate backing bo */
 	gsize = (union omap_gem_size){
 		.bytes = PAGE_ALIGN(mode_cmd.pitches[0] * mode_cmd.height),
 	};
 	DBG("allocating %d bytes for fb %d", gsize.bytes, dev->primary->index);
 	fbdev->bo = omap_gem_new(dev, gsize, OMAP_BO_SCANOUT | OMAP_BO_WC);
 	if (!fbdev->bo) {
 		dev_err(dev->dev, "failed to allocate buffer object\n");
 		ret = -ENOMEM;
 		goto fail;
 	}

 	fb = omap_framebuffer_init(dev, &mode_cmd, &fbdev->bo);
 	if (IS_ERR(fb)) {
 		dev_err(dev->dev, "failed to allocate fb\n");
 		/* note: if fb creation failed, we can't rely on fb destroy
 		 * to unref the bo:
 		 */
 		drm_gem_object_unreference(fbdev->bo);
 		ret = PTR_ERR(fb);
 		goto fail;
 	}

 	/* note: this keeps the bo pinned.. which is perhaps not ideal,
 	 * but is needed as long as we use fb_mmap() to mmap to userspace
 	 * (since this happens using fix.smem_start).  Possibly we could
 	 * implement our own mmap using GEM mmap support to avoid this
 	 * (non-tiled buffer doesn't need to be pinned for fbcon to write
 	 * to it).  Then we just need to be sure that we are able to re-
 	 * pin it in case of an opps.
 	 */
 	ret = omap_gem_get_paddr(fbdev->bo, &paddr, true);
 	if (ret) {
 		dev_err(dev->dev,
 			"could not map (paddr)!  Skipping framebuffer alloc\n");
 		ret = -ENOMEM;
 		goto fail;
 	}

 	mutex_lock(&dev->struct_mutex);

 	fbi = framebuffer_alloc(0, dev->dev);
 	if (!fbi) {
 		dev_err(dev->dev, "failed to allocate fb info\n");
 		ret = -ENOMEM;
 		goto fail_unlock;
 	}

 	DBG("fbi=%p, dev=%p", fbi, dev);

 	fbdev->fb = fb;
 	helper->fb = fb;
 	helper->fbdev = fbi;

 	fbi->par = helper;
 	fbi->flags = FBINFO_DEFAULT;
 	fbi->fbops = &omap_fb_ops;

 	strcpy(fbi->fix.id, MODULE_NAME);

 	ret = fb_alloc_cmap(&fbi->cmap, 256, 0);
 	if (ret) {
 		ret = -ENOMEM;
 		goto fail_unlock;
 	}

 	drm_fb_helper_fill_fix(fbi, fb->pitches[0], fb->depth);
 	drm_fb_helper_fill_var(fbi, helper, sizes->fb_width, sizes->fb_height);

 	dev->mode_config.fb_base = paddr;

 	fbi->screen_base = omap_gem_vaddr(fbdev->bo);
 	fbi->screen_size = fbdev->bo->size;
 	fbi->fix.smem_start = paddr;
 	fbi->fix.smem_len = fbdev->bo->size;

 	/* if we have DMM, then we can use it for scrolling by just
 	 * shuffling pages around in DMM rather than doing sw blit.
 	 */
 	if (fbdev->ywrap_enabled) {
 		DRM_INFO("Enabling DMM ywrap scrolling\n");
 		fbi->flags |= FBINFO_HWACCEL_YWRAP | FBINFO_READS_FAST;
 		fbi->fix.ywrapstep = 1;
 	}


 	DBG("par=%p, %dx%d", fbi->par, fbi->var.xres, fbi->var.yres);
 	DBG("allocated %dx%d fb", fbdev->fb->width, fbdev->fb->height);

 	mutex_unlock(&dev->struct_mutex);

 	return 0;

 fail_unlock:
 	mutex_unlock(&dev->struct_mutex);
 fail:

 	if (ret) {
 		if (fbi)
 			framebuffer_release(fbi);
 		if (fb) {
 			drm_framebuffer_unregister_private(fb);
 			drm_framebuffer_remove(fb);
 		}
 	}

 	return ret;
 }

 static const struct drm_fb_helper_funcs omap_fb_helper_funcs = {
 	.fb_probe = omap_fbdev_create,
 };

 static struct drm_fb_helper *get_fb(struct fb_info *fbi)
 {
 	if (!fbi || strcmp(fbi->fix.id, MODULE_NAME)) {
 		/* these are not the fb's you're looking for */
 		return NULL;
 	}
 	return fbi->par;
 }

 /* flush an area of the framebuffer (in case of manual update display that
  * is not automatically flushed)
  */
 static void omap_fbdev_flush(struct fb_info *fbi, int x, int y, int w, int h)
 {
 	struct drm_fb_helper *helper = get_fb(fbi);

 	if (!helper)
 		return;

 	VERB("flush fbdev: %d,%d %dx%d, fbi=%p", x, y, w, h, fbi);

 	omap_framebuffer_flush(helper->fb, x, y, w, h);
 }

 /* initialize fbdev helper */
 struct drm_fb_helper *omap_fbdev_init(struct drm_device *dev)
 {
 	struct omap_drm_private *priv = dev->dev_private;
 	struct omap_fbdev *fbdev = NULL;
 	struct drm_fb_helper *helper;
 	int ret = 0;

 	fbdev = kzalloc(sizeof(*fbdev), GFP_KERNEL);
 	if (!fbdev)
 		goto fail;

 	INIT_WORK(&fbdev->work, pan_worker);

 	helper = &fbdev->base;

 	drm_fb_helper_prepare(dev, helper, &omap_fb_helper_funcs);

 	ret = drm_fb_helper_init(dev, helper,
 			priv->num_crtcs, priv->num_connectors);
 	if (ret) {
 		dev_err(dev->dev, "could not init fbdev: ret=%d\n", ret);
 		goto fail;
 	}

 	ret = drm_fb_helper_single_add_all_connectors(helper);
 	if (ret)
 		goto fini;

 	/* disable all the possible outputs/crtcs before entering KMS mode */
 	drm_helper_disable_unused_functions(dev);

 	ret = drm_fb_helper_initial_config(helper, 32);
 	if (ret)
 		goto fini;

 	priv->fbdev = helper;

 	return helper;

 fini:
 	drm_fb_helper_fini(helper);
 fail:
 	kfree(fbdev);
 	return NULL;
 }

 void omap_fbdev_free(struct drm_device *dev)
 {
 	struct omap_drm_private *priv = dev->dev_private;
 	struct drm_fb_helper *helper = priv->fbdev;
 	struct omap_fbdev *fbdev;
 	struct fb_info *fbi;

 	DBG();

 	fbi = helper->fbdev;

 	/* only cleanup framebuffer if it is present */
 	if (fbi) {
 		unregister_framebuffer(fbi);
 		framebuffer_release(fbi);
 	}

 	drm_fb_helper_fini(helper);

 	fbdev = to_omap_fbdev(priv->fbdev);

 	/* release the ref taken in omap_fbdev_create() */
 	omap_gem_put_paddr(fbdev->bo);

 	/* this will free the backing object */
 	if (fbdev->fb) {
 		drm_framebuffer_unregister_private(fbdev->fb);
 		drm_framebuffer_remove(fbdev->fb);
 	}

 	kfree(fbdev);

 	priv->fbdev = NULL;
 }
	/*
	* drivers/gpu/drm/omapdrm/omap_fbdev.c
	*
	* Copyright (C) 2011 Texas Instruments
	* Author: Rob Clark <rob@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 "omap_drv.h"

	#include "drm_crtc.h"
	#include "drm_fb_helper.h"

	MODULE_PARM_DESC(ywrap, "Enable ywrap scrolling (omap44xx and later, default 'y')");
	static bool ywrap_enabled = true;
	module_param_named(ywrap, ywrap_enabled, bool, 0644);

	/*
	* fbdev funcs, to implement legacy fbdev interface on top of drm driver
	*/

	#define to_omap_fbdev(x) container_of(x, struct omap_fbdev, base)

	struct omap_fbdev {
	struct drm_fb_helper base;
	struct drm_framebuffer *fb;
	struct drm_gem_object *bo;
	bool ywrap_enabled;

	/* for deferred dmm roll when getting called in atomic ctx */
	struct work_struct work;
	};

	static void omap_fbdev_flush(struct fb_info *fbi, int x, int y, int w, int h);
	static struct drm_fb_helper get_fb(struct fb_info fbi);

	static ssize_t omap_fbdev_write(struct fb_info fbi, const char __user buf,
	size_t count, loff_t *ppos)
	{
	ssize_t res;

	res = fb_sys_write(fbi, buf, count, ppos);
	omap_fbdev_flush(fbi, 0, 0, fbi->var.xres, fbi->var.yres);

	return res;
	}

	static void omap_fbdev_fillrect(struct fb_info *fbi,
	const struct fb_fillrect *rect)
	{
	sys_fillrect(fbi, rect);
	omap_fbdev_flush(fbi, rect->dx, rect->dy, rect->width, rect->height);
	}

	static void omap_fbdev_copyarea(struct fb_info *fbi,
	const struct fb_copyarea *area)
	{
	sys_copyarea(fbi, area);
	omap_fbdev_flush(fbi, area->dx, area->dy, area->width, area->height);
	}

	static void omap_fbdev_imageblit(struct fb_info *fbi,
	const struct fb_image *image)
	{
	sys_imageblit(fbi, image);
	omap_fbdev_flush(fbi, image->dx, image->dy,
	image->width, image->height);
	}

	static void pan_worker(struct work_struct *work)
	{
	struct omap_fbdev *fbdev = container_of(work, struct omap_fbdev, work);
	struct fb_info *fbi = fbdev->base.fbdev;
	int npages;

	/* DMM roll shifts in 4K pages: */
	npages = fbi->fix.line_length >> PAGE_SHIFT;
	omap_gem_roll(fbdev->bo, fbi->var.yoffset * npages);
	}

	static int omap_fbdev_pan_display(struct fb_var_screeninfo *var,
	struct fb_info *fbi)
	{
	struct drm_fb_helper *helper = get_fb(fbi);
	struct omap_fbdev *fbdev = to_omap_fbdev(helper);

	if (!helper)
	goto fallback;

	if (!fbdev->ywrap_enabled)
	goto fallback;

	if (drm_can_sleep()) {
	pan_worker(&fbdev->work);
	} else {
	struct omap_drm_private *priv = helper->dev->dev_private;
	queue_work(priv->wq, &fbdev->work);
	}

	return 0;

	fallback:
	return drm_fb_helper_pan_display(var, fbi);
	}

	static struct fb_ops omap_fb_ops = {
	.owner = THIS_MODULE,

	/* Note: to properly handle manual update displays, we wrap the
	* basic fbdev ops which write to the framebuffer
	*/
	.fb_read = fb_sys_read,
	.fb_write = omap_fbdev_write,
	.fb_fillrect = omap_fbdev_fillrect,
	.fb_copyarea = omap_fbdev_copyarea,
	.fb_imageblit = omap_fbdev_imageblit,

	.fb_check_var = drm_fb_helper_check_var,
	.fb_set_par = drm_fb_helper_set_par,
	.fb_pan_display = omap_fbdev_pan_display,
	.fb_blank = drm_fb_helper_blank,
	.fb_setcmap = drm_fb_helper_setcmap,
	};

	static int omap_fbdev_create(struct drm_fb_helper *helper,
	struct drm_fb_helper_surface_size *sizes)
	{
	struct omap_fbdev *fbdev = to_omap_fbdev(helper);
	struct drm_device *dev = helper->dev;
	struct omap_drm_private *priv = dev->dev_private;
	struct drm_framebuffer *fb = NULL;
	union omap_gem_size gsize;
	struct fb_info *fbi = NULL;
	struct drm_mode_fb_cmd2 mode_cmd = {0};
	dma_addr_t paddr;
	int ret;

	/* only doing ARGB32 since this is what is needed to alpha-blend
	* with video overlays:
	*/
	sizes->surface_bpp = 32;
	sizes->surface_depth = 32;

	DBG("create fbdev: %dx%d@%d (%dx%d)", sizes->surface_width,
	sizes->surface_height, sizes->surface_bpp,
	sizes->fb_width, sizes->fb_height);

	mode_cmd.pixel_format = drm_mode_legacy_fb_format(sizes->surface_bpp,
	sizes->surface_depth);

	mode_cmd.width = sizes->surface_width;
	mode_cmd.height = sizes->surface_height;

	mode_cmd.pitches[0] = align_pitch(
	mode_cmd.width * ((sizes->surface_bpp + 7) / 8),
	mode_cmd.width, sizes->surface_bpp);

	fbdev->ywrap_enabled = priv->has_dmm && ywrap_enabled;
	if (fbdev->ywrap_enabled) {
	/* need to align pitch to page size if using DMM scrolling */
	mode_cmd.pitches[0] = ALIGN(mode_cmd.pitches[0], PAGE_SIZE);
	}

	/* allocate backing bo */
	gsize = (union omap_gem_size){
	.bytes = PAGE_ALIGN(mode_cmd.pitches[0] * mode_cmd.height),
	};
	DBG("allocating %d bytes for fb %d", gsize.bytes, dev->primary->index);
	fbdev->bo = omap_gem_new(dev, gsize, OMAP_BO_SCANOUT \| OMAP_BO_WC);
	if (!fbdev->bo) {
	dev_err(dev->dev, "failed to allocate buffer object\n");
	ret = -ENOMEM;
	goto fail;
	}

	fb = omap_framebuffer_init(dev, &mode_cmd, &fbdev->bo);
	if (IS_ERR(fb)) {
	dev_err(dev->dev, "failed to allocate fb\n");
	/* note: if fb creation failed, we can't rely on fb destroy
	* to unref the bo:
	*/
	drm_gem_object_unreference(fbdev->bo);
	ret = PTR_ERR(fb);
	goto fail;
	}

	/* note: this keeps the bo pinned.. which is perhaps not ideal,
	* but is needed as long as we use fb_mmap() to mmap to userspace
	* (since this happens using fix.smem_start). Possibly we could
	* implement our own mmap using GEM mmap support to avoid this
	* (non-tiled buffer doesn't need to be pinned for fbcon to write
	* to it). Then we just need to be sure that we are able to re-
	* pin it in case of an opps.
	*/
	ret = omap_gem_get_paddr(fbdev->bo, &paddr, true);
	if (ret) {
	dev_err(dev->dev,
	"could not map (paddr)! Skipping framebuffer alloc\n");
	ret = -ENOMEM;
	goto fail;
	}

	mutex_lock(&dev->struct_mutex);

	fbi = framebuffer_alloc(0, dev->dev);
	if (!fbi) {
	dev_err(dev->dev, "failed to allocate fb info\n");
	ret = -ENOMEM;
	goto fail_unlock;
	}

	DBG("fbi=%p, dev=%p", fbi, dev);

	fbdev->fb = fb;
	helper->fb = fb;
	helper->fbdev = fbi;

	fbi->par = helper;
	fbi->flags = FBINFO_DEFAULT;
	fbi->fbops = &omap_fb_ops;

	strcpy(fbi->fix.id, MODULE_NAME);

	ret = fb_alloc_cmap(&fbi->cmap, 256, 0);
	if (ret) {
	ret = -ENOMEM;
	goto fail_unlock;
	}

	drm_fb_helper_fill_fix(fbi, fb->pitches[0], fb->depth);
	drm_fb_helper_fill_var(fbi, helper, sizes->fb_width, sizes->fb_height);

	dev->mode_config.fb_base = paddr;

	fbi->screen_base = omap_gem_vaddr(fbdev->bo);
	fbi->screen_size = fbdev->bo->size;
	fbi->fix.smem_start = paddr;
	fbi->fix.smem_len = fbdev->bo->size;

	/* if we have DMM, then we can use it for scrolling by just
	* shuffling pages around in DMM rather than doing sw blit.
	*/
	if (fbdev->ywrap_enabled) {
	DRM_INFO("Enabling DMM ywrap scrolling\n");
	fbi->flags \|= FBINFO_HWACCEL_YWRAP \| FBINFO_READS_FAST;
	fbi->fix.ywrapstep = 1;
	}


	DBG("par=%p, %dx%d", fbi->par, fbi->var.xres, fbi->var.yres);
	DBG("allocated %dx%d fb", fbdev->fb->width, fbdev->fb->height);

	mutex_unlock(&dev->struct_mutex);

	return 0;

	fail_unlock:
	mutex_unlock(&dev->struct_mutex);
	fail:

	if (ret) {
	if (fbi)
	framebuffer_release(fbi);
	if (fb) {
	drm_framebuffer_unregister_private(fb);
	drm_framebuffer_remove(fb);
	}
	}

	return ret;
	}

	static const struct drm_fb_helper_funcs omap_fb_helper_funcs = {
	.fb_probe = omap_fbdev_create,
	};

	static struct drm_fb_helper get_fb(struct fb_info fbi)
	{
	if (!fbi \|\| strcmp(fbi->fix.id, MODULE_NAME)) {
	/* these are not the fb's you're looking for */
	return NULL;
	}
	return fbi->par;
	}

	/* flush an area of the framebuffer (in case of manual update display that
	* is not automatically flushed)
	*/
	static void omap_fbdev_flush(struct fb_info *fbi, int x, int y, int w, int h)
	{
	struct drm_fb_helper *helper = get_fb(fbi);

	if (!helper)
	return;

	VERB("flush fbdev: %d,%d %dx%d, fbi=%p", x, y, w, h, fbi);

	omap_framebuffer_flush(helper->fb, x, y, w, h);
	}

	/* initialize fbdev helper */
	struct drm_fb_helper omap_fbdev_init(struct drm_device dev)
	{
	struct omap_drm_private *priv = dev->dev_private;
	struct omap_fbdev *fbdev = NULL;
	struct drm_fb_helper *helper;
	int ret = 0;

	fbdev = kzalloc(sizeof(*fbdev), GFP_KERNEL);
	if (!fbdev)
	goto fail;

	INIT_WORK(&fbdev->work, pan_worker);

	helper = &fbdev->base;

	drm_fb_helper_prepare(dev, helper, &omap_fb_helper_funcs);

	ret = drm_fb_helper_init(dev, helper,
	priv->num_crtcs, priv->num_connectors);
	if (ret) {
	dev_err(dev->dev, "could not init fbdev: ret=%d\n", ret);
	goto fail;
	}

	ret = drm_fb_helper_single_add_all_connectors(helper);
	if (ret)
	goto fini;

	/* disable all the possible outputs/crtcs before entering KMS mode */
	drm_helper_disable_unused_functions(dev);

	ret = drm_fb_helper_initial_config(helper, 32);
	if (ret)
	goto fini;

	priv->fbdev = helper;

	return helper;

	fini:
	drm_fb_helper_fini(helper);
	fail:
	kfree(fbdev);
	return NULL;
	}

	void omap_fbdev_free(struct drm_device *dev)
	{
	struct omap_drm_private *priv = dev->dev_private;
	struct drm_fb_helper *helper = priv->fbdev;
	struct omap_fbdev *fbdev;
	struct fb_info *fbi;

	DBG();

	fbi = helper->fbdev;

	/* only cleanup framebuffer if it is present */
	if (fbi) {
	unregister_framebuffer(fbi);
	framebuffer_release(fbi);
	}

	drm_fb_helper_fini(helper);

	fbdev = to_omap_fbdev(priv->fbdev);

	/* release the ref taken in omap_fbdev_create() */
	omap_gem_put_paddr(fbdev->bo);

	/* this will free the backing object */
	if (fbdev->fb) {
	drm_framebuffer_unregister_private(fbdev->fb);
	drm_framebuffer_remove(fbdev->fb);
	}

	kfree(fbdev);

	priv->fbdev = NULL;
	}