drivers/gpu/drm/drm_fb_cma_helper.c - kernel/msm-4.19 - Gitiles

 /*
  * drm kms/fb cma (contiguous memory allocator) helper functions
  *
  * Copyright (C) 2012 Analog Device Inc.
  *   Author: Lars-Peter Clausen <lars@metafoo.de>
  *
  * Based on udl_fbdev.c
  *  Copyright (C) 2012 Red Hat
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
  * as published by the Free Software Foundation; either version 2
  * of the License, or (at your option) any later version.
  * 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.
  */

 #include <drm/drmP.h>
 #include <drm/drm_crtc.h>
 #include <drm/drm_fb_helper.h>
 #include <drm/drm_crtc_helper.h>
 #include <drm/drm_gem_cma_helper.h>
 #include <drm/drm_fb_cma_helper.h>
 #include <linux/module.h>

 struct drm_fb_cma {
 	struct drm_framebuffer		fb;
 	struct drm_gem_cma_object	*obj[4];
 };

 struct drm_fbdev_cma {
 	struct drm_fb_helper	fb_helper;
 	struct drm_fb_cma	*fb;
 };

 static inline struct drm_fbdev_cma *to_fbdev_cma(struct drm_fb_helper *helper)
 {
 	return container_of(helper, struct drm_fbdev_cma, fb_helper);
 }

 static inline struct drm_fb_cma *to_fb_cma(struct drm_framebuffer *fb)
 {
 	return container_of(fb, struct drm_fb_cma, fb);
 }

 static void drm_fb_cma_destroy(struct drm_framebuffer *fb)
 {
 	struct drm_fb_cma *fb_cma = to_fb_cma(fb);
 	int i;

 	for (i = 0; i < 4; i++) {
 		if (fb_cma->obj[i])
 			drm_gem_object_unreference_unlocked(&fb_cma->obj[i]->base);
 	}

 	drm_framebuffer_cleanup(fb);
 	kfree(fb_cma);
 }

 static int drm_fb_cma_create_handle(struct drm_framebuffer *fb,
 	struct drm_file *file_priv, unsigned int *handle)
 {
 	struct drm_fb_cma *fb_cma = to_fb_cma(fb);

 	return drm_gem_handle_create(file_priv,
 			&fb_cma->obj[0]->base, handle);
 }

 static struct drm_framebuffer_funcs drm_fb_cma_funcs = {
 	.destroy	= drm_fb_cma_destroy,
 	.create_handle	= drm_fb_cma_create_handle,
 };

 static struct drm_fb_cma *drm_fb_cma_alloc(struct drm_device *dev,
 	const const struct drm_mode_fb_cmd2 *mode_cmd, struct drm_gem_cma_object **obj,
 	unsigned int num_planes)
 {
 	struct drm_fb_cma *fb_cma;
 	int ret;
 	int i;

 	fb_cma = kzalloc(sizeof(*fb_cma), GFP_KERNEL);
 	if (!fb_cma)
 		return ERR_PTR(-ENOMEM);

 	drm_helper_mode_fill_fb_struct(&fb_cma->fb, mode_cmd);

 	for (i = 0; i < num_planes; i++)
 		fb_cma->obj[i] = obj[i];

 	ret = drm_framebuffer_init(dev, &fb_cma->fb, &drm_fb_cma_funcs);
 	if (ret) {
 		dev_err(dev->dev, "Failed to initialize framebuffer: %d\n", ret);
 		kfree(fb_cma);
 		return ERR_PTR(ret);
 	}

 	return fb_cma;
 }

 /**
  * drm_fb_cma_create() - (struct drm_mode_config_funcs *)->fb_create callback function
  *
  * If your hardware has special alignment or pitch requirements these should be
  * checked before calling this function.
  */
 struct drm_framebuffer *drm_fb_cma_create(struct drm_device *dev,
 	struct drm_file *file_priv, const struct drm_mode_fb_cmd2 *mode_cmd)
 {
 	struct drm_fb_cma *fb_cma;
 	struct drm_gem_cma_object *objs[4];
 	struct drm_gem_object *obj;
 	unsigned int hsub;
 	unsigned int vsub;
 	int ret;
 	int i;

 	hsub = drm_format_horz_chroma_subsampling(mode_cmd->pixel_format);
 	vsub = drm_format_vert_chroma_subsampling(mode_cmd->pixel_format);

 	for (i = 0; i < drm_format_num_planes(mode_cmd->pixel_format); i++) {
 		unsigned int width = mode_cmd->width / (i ? hsub : 1);
 		unsigned int height = mode_cmd->height / (i ? vsub : 1);
 		unsigned int min_size;

 		obj = drm_gem_object_lookup(dev, file_priv, mode_cmd->handles[i]);
 		if (!obj) {
 			dev_err(dev->dev, "Failed to lookup GEM object\n");
 			ret = -ENXIO;
 			goto err_gem_object_unreference;
 		}

 		min_size = (height - 1) * mode_cmd->pitches[i]
 			 + width * drm_format_plane_cpp(mode_cmd->pixel_format, i)
 			 + mode_cmd->offsets[i];

 		if (obj->size < min_size) {
 			drm_gem_object_unreference_unlocked(obj);
 			ret = -EINVAL;
 			goto err_gem_object_unreference;
 		}
 		objs[i] = to_drm_gem_cma_obj(obj);
 	}

 	fb_cma = drm_fb_cma_alloc(dev, mode_cmd, objs, i);
 	if (IS_ERR(fb_cma)) {
 		ret = PTR_ERR(fb_cma);
 		goto err_gem_object_unreference;
 	}

 	return &fb_cma->fb;

 err_gem_object_unreference:
 	for (i--; i >= 0; i--)
 		drm_gem_object_unreference_unlocked(&objs[i]->base);
 	return ERR_PTR(ret);
 }
 EXPORT_SYMBOL_GPL(drm_fb_cma_create);

 /**
  * drm_fb_cma_get_gem_obj() - Get CMA GEM object for framebuffer
  * @fb: The framebuffer
  * @plane: Which plane
  *
  * Return the CMA GEM object for given framebuffer.
  *
  * This function will usually be called from the CRTC callback functions.
  */
 struct drm_gem_cma_object *drm_fb_cma_get_gem_obj(struct drm_framebuffer *fb,
 	unsigned int plane)
 {
 	struct drm_fb_cma *fb_cma = to_fb_cma(fb);

 	if (plane >= 4)
 		return NULL;

 	return fb_cma->obj[plane];
 }
 EXPORT_SYMBOL_GPL(drm_fb_cma_get_gem_obj);

 #ifdef CONFIG_DEBUG_FS
 /*
  * drm_fb_cma_describe() - Helper to dump information about a single
  * CMA framebuffer object
  */
 static void drm_fb_cma_describe(struct drm_framebuffer *fb, struct seq_file *m)
 {
 	struct drm_fb_cma *fb_cma = to_fb_cma(fb);
 	int i, n = drm_format_num_planes(fb->pixel_format);

 	seq_printf(m, "fb: %dx%d@%4.4s\n", fb->width, fb->height,
 			(char *)&fb->pixel_format);

 	for (i = 0; i < n; i++) {
 		seq_printf(m, "   %d: offset=%d pitch=%d, obj: ",
 				i, fb->offsets[i], fb->pitches[i]);
 		drm_gem_cma_describe(fb_cma->obj[i], m);
 	}
 }

 /**
  * drm_fb_cma_debugfs_show() - Helper to list CMA framebuffer objects
  * in debugfs.
  */
 int drm_fb_cma_debugfs_show(struct seq_file *m, void *arg)
 {
 	struct drm_info_node *node = (struct drm_info_node *) m->private;
 	struct drm_device *dev = node->minor->dev;
 	struct drm_framebuffer *fb;

 	mutex_lock(&dev->mode_config.fb_lock);
 	drm_for_each_fb(fb, dev)
 		drm_fb_cma_describe(fb, m);
 	mutex_unlock(&dev->mode_config.fb_lock);

 	return 0;
 }
 EXPORT_SYMBOL_GPL(drm_fb_cma_debugfs_show);
 #endif

 static struct fb_ops drm_fbdev_cma_ops = {
 	.owner		= THIS_MODULE,
 	.fb_fillrect	= drm_fb_helper_sys_fillrect,
 	.fb_copyarea	= drm_fb_helper_sys_copyarea,
 	.fb_imageblit	= drm_fb_helper_sys_imageblit,
 	.fb_check_var	= drm_fb_helper_check_var,
 	.fb_set_par	= drm_fb_helper_set_par,
 	.fb_blank	= drm_fb_helper_blank,
 	.fb_pan_display	= drm_fb_helper_pan_display,
 	.fb_setcmap	= drm_fb_helper_setcmap,
 };

 static int drm_fbdev_cma_create(struct drm_fb_helper *helper,
 	struct drm_fb_helper_surface_size *sizes)
 {
 	struct drm_fbdev_cma *fbdev_cma = to_fbdev_cma(helper);
 	struct drm_mode_fb_cmd2 mode_cmd = { 0 };
 	struct drm_device *dev = helper->dev;
 	struct drm_gem_cma_object *obj;
 	struct drm_framebuffer *fb;
 	unsigned int bytes_per_pixel;
 	unsigned long offset;
 	struct fb_info *fbi;
 	size_t size;
 	int ret;

 	DRM_DEBUG_KMS("surface width(%d), height(%d) and bpp(%d)\n",
 			sizes->surface_width, sizes->surface_height,
 			sizes->surface_bpp);

 	bytes_per_pixel = DIV_ROUND_UP(sizes->surface_bpp, 8);

 	mode_cmd.width = sizes->surface_width;
 	mode_cmd.height = sizes->surface_height;
 	mode_cmd.pitches[0] = sizes->surface_width * bytes_per_pixel;
 	mode_cmd.pixel_format = drm_mode_legacy_fb_format(sizes->surface_bpp,
 		sizes->surface_depth);

 	size = mode_cmd.pitches[0] * mode_cmd.height;
 	obj = drm_gem_cma_create(dev, size);
 	if (IS_ERR(obj))
 		return -ENOMEM;

 	fbi = drm_fb_helper_alloc_fbi(helper);
 	if (IS_ERR(fbi)) {
 		ret = PTR_ERR(fbi);
 		goto err_gem_free_object;
 	}

 	fbdev_cma->fb = drm_fb_cma_alloc(dev, &mode_cmd, &obj, 1);
 	if (IS_ERR(fbdev_cma->fb)) {
 		dev_err(dev->dev, "Failed to allocate DRM framebuffer.\n");
 		ret = PTR_ERR(fbdev_cma->fb);
 		goto err_fb_info_destroy;
 	}

 	fb = &fbdev_cma->fb->fb;
 	helper->fb = fb;

 	fbi->par = helper;
 	fbi->flags = FBINFO_FLAG_DEFAULT;
 	fbi->fbops = &drm_fbdev_cma_ops;

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

 	offset = fbi->var.xoffset * bytes_per_pixel;
 	offset += fbi->var.yoffset * fb->pitches[0];

 	dev->mode_config.fb_base = (resource_size_t)obj->paddr;
 	fbi->screen_base = obj->vaddr + offset;
 	fbi->fix.smem_start = (unsigned long)(obj->paddr + offset);
 	fbi->screen_size = size;
 	fbi->fix.smem_len = size;

 	return 0;

 err_fb_info_destroy:
 	drm_fb_helper_release_fbi(helper);
 err_gem_free_object:
 	dev->driver->gem_free_object(&obj->base);
 	return ret;
 }

 static const struct drm_fb_helper_funcs drm_fb_cma_helper_funcs = {
 	.fb_probe = drm_fbdev_cma_create,
 };

 /**
  * drm_fbdev_cma_init() - Allocate and initializes a drm_fbdev_cma struct
  * @dev: DRM device
  * @preferred_bpp: Preferred bits per pixel for the device
  * @num_crtc: Number of CRTCs
  * @max_conn_count: Maximum number of connectors
  *
  * Returns a newly allocated drm_fbdev_cma struct or a ERR_PTR.
  */
 struct drm_fbdev_cma *drm_fbdev_cma_init(struct drm_device *dev,
 	unsigned int preferred_bpp, unsigned int num_crtc,
 	unsigned int max_conn_count)
 {
 	struct drm_fbdev_cma *fbdev_cma;
 	struct drm_fb_helper *helper;
 	int ret;

 	fbdev_cma = kzalloc(sizeof(*fbdev_cma), GFP_KERNEL);
 	if (!fbdev_cma) {
 		dev_err(dev->dev, "Failed to allocate drm fbdev.\n");
 		return ERR_PTR(-ENOMEM);
 	}

 	helper = &fbdev_cma->fb_helper;

 	drm_fb_helper_prepare(dev, helper, &drm_fb_cma_helper_funcs);

 	ret = drm_fb_helper_init(dev, helper, num_crtc, max_conn_count);
 	if (ret < 0) {
 		dev_err(dev->dev, "Failed to initialize drm fb helper.\n");
 		goto err_free;
 	}

 	ret = drm_fb_helper_single_add_all_connectors(helper);
 	if (ret < 0) {
 		dev_err(dev->dev, "Failed to add connectors.\n");
 		goto err_drm_fb_helper_fini;

 	}

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

 	ret = drm_fb_helper_initial_config(helper, preferred_bpp);
 	if (ret < 0) {
 		dev_err(dev->dev, "Failed to set initial hw configuration.\n");
 		goto err_drm_fb_helper_fini;
 	}

 	return fbdev_cma;

 err_drm_fb_helper_fini:
 	drm_fb_helper_fini(helper);
 err_free:
 	kfree(fbdev_cma);

 	return ERR_PTR(ret);
 }
 EXPORT_SYMBOL_GPL(drm_fbdev_cma_init);

 /**
  * drm_fbdev_cma_fini() - Free drm_fbdev_cma struct
  * @fbdev_cma: The drm_fbdev_cma struct
  */
 void drm_fbdev_cma_fini(struct drm_fbdev_cma *fbdev_cma)
 {
 	drm_fb_helper_unregister_fbi(&fbdev_cma->fb_helper);
 	drm_fb_helper_release_fbi(&fbdev_cma->fb_helper);

 	if (fbdev_cma->fb) {
 		drm_framebuffer_unregister_private(&fbdev_cma->fb->fb);
 		drm_fb_cma_destroy(&fbdev_cma->fb->fb);
 	}

 	drm_fb_helper_fini(&fbdev_cma->fb_helper);
 	kfree(fbdev_cma);
 }
 EXPORT_SYMBOL_GPL(drm_fbdev_cma_fini);

 /**
  * drm_fbdev_cma_restore_mode() - Restores initial framebuffer mode
  * @fbdev_cma: The drm_fbdev_cma struct, may be NULL
  *
  * This function is usually called from the DRM drivers lastclose callback.
  */
 void drm_fbdev_cma_restore_mode(struct drm_fbdev_cma *fbdev_cma)
 {
 	if (fbdev_cma)
 		drm_fb_helper_restore_fbdev_mode_unlocked(&fbdev_cma->fb_helper);
 }
 EXPORT_SYMBOL_GPL(drm_fbdev_cma_restore_mode);

 /**
  * drm_fbdev_cma_hotplug_event() - Poll for hotpulug events
  * @fbdev_cma: The drm_fbdev_cma struct, may be NULL
  *
  * This function is usually called from the DRM drivers output_poll_changed
  * callback.
  */
 void drm_fbdev_cma_hotplug_event(struct drm_fbdev_cma *fbdev_cma)
 {
 	if (fbdev_cma)
 		drm_fb_helper_hotplug_event(&fbdev_cma->fb_helper);
 }
 EXPORT_SYMBOL_GPL(drm_fbdev_cma_hotplug_event);
	/*
	* drm kms/fb cma (contiguous memory allocator) helper functions
	*
	* Copyright (C) 2012 Analog Device Inc.
	* Author: Lars-Peter Clausen <lars@metafoo.de>
	*
	* Based on udl_fbdev.c
	* Copyright (C) 2012 Red Hat
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License
	* as published by the Free Software Foundation; either version 2
	* of the License, or (at your option) any later version.
	* 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.
	*/

	#include <drm/drmP.h>
	#include <drm/drm_crtc.h>
	#include <drm/drm_fb_helper.h>
	#include <drm/drm_crtc_helper.h>
	#include <drm/drm_gem_cma_helper.h>
	#include <drm/drm_fb_cma_helper.h>
	#include <linux/module.h>

	struct drm_fb_cma {
	struct drm_framebuffer fb;
	struct drm_gem_cma_object *obj[4];
	};

	struct drm_fbdev_cma {
	struct drm_fb_helper fb_helper;
	struct drm_fb_cma *fb;
	};

	static inline struct drm_fbdev_cma to_fbdev_cma(struct drm_fb_helper helper)
	{
	return container_of(helper, struct drm_fbdev_cma, fb_helper);
	}

	static inline struct drm_fb_cma to_fb_cma(struct drm_framebuffer fb)
	{
	return container_of(fb, struct drm_fb_cma, fb);
	}

	static void drm_fb_cma_destroy(struct drm_framebuffer *fb)
	{
	struct drm_fb_cma *fb_cma = to_fb_cma(fb);
	int i;

	for (i = 0; i < 4; i++) {
	if (fb_cma->obj[i])
	drm_gem_object_unreference_unlocked(&fb_cma->obj[i]->base);
	}

	drm_framebuffer_cleanup(fb);
	kfree(fb_cma);
	}

	static int drm_fb_cma_create_handle(struct drm_framebuffer *fb,
	struct drm_file file_priv, unsigned int handle)
	{
	struct drm_fb_cma *fb_cma = to_fb_cma(fb);

	return drm_gem_handle_create(file_priv,
	&fb_cma->obj[0]->base, handle);
	}

	static struct drm_framebuffer_funcs drm_fb_cma_funcs = {
	.destroy = drm_fb_cma_destroy,
	.create_handle = drm_fb_cma_create_handle,
	};

	static struct drm_fb_cma drm_fb_cma_alloc(struct drm_device dev,
	const const struct drm_mode_fb_cmd2 mode_cmd, struct drm_gem_cma_object *obj,
	unsigned int num_planes)
	{
	struct drm_fb_cma *fb_cma;
	int ret;
	int i;

	fb_cma = kzalloc(sizeof(*fb_cma), GFP_KERNEL);
	if (!fb_cma)
	return ERR_PTR(-ENOMEM);

	drm_helper_mode_fill_fb_struct(&fb_cma->fb, mode_cmd);

	for (i = 0; i < num_planes; i++)
	fb_cma->obj[i] = obj[i];

	ret = drm_framebuffer_init(dev, &fb_cma->fb, &drm_fb_cma_funcs);
	if (ret) {
	dev_err(dev->dev, "Failed to initialize framebuffer: %d\n", ret);
	kfree(fb_cma);
	return ERR_PTR(ret);
	}

	return fb_cma;
	}

	/**
	* drm_fb_cma_create() - (struct drm_mode_config_funcs *)->fb_create callback function
	*
	* If your hardware has special alignment or pitch requirements these should be
	* checked before calling this function.
	*/
	struct drm_framebuffer drm_fb_cma_create(struct drm_device dev,
	struct drm_file file_priv, const struct drm_mode_fb_cmd2 mode_cmd)
	{
	struct drm_fb_cma *fb_cma;
	struct drm_gem_cma_object *objs[4];
	struct drm_gem_object *obj;
	unsigned int hsub;
	unsigned int vsub;
	int ret;
	int i;

	hsub = drm_format_horz_chroma_subsampling(mode_cmd->pixel_format);
	vsub = drm_format_vert_chroma_subsampling(mode_cmd->pixel_format);

	for (i = 0; i < drm_format_num_planes(mode_cmd->pixel_format); i++) {
	unsigned int width = mode_cmd->width / (i ? hsub : 1);
	unsigned int height = mode_cmd->height / (i ? vsub : 1);
	unsigned int min_size;

	obj = drm_gem_object_lookup(dev, file_priv, mode_cmd->handles[i]);
	if (!obj) {
	dev_err(dev->dev, "Failed to lookup GEM object\n");
	ret = -ENXIO;
	goto err_gem_object_unreference;
	}

	min_size = (height - 1) * mode_cmd->pitches[i]
	+ width * drm_format_plane_cpp(mode_cmd->pixel_format, i)
	+ mode_cmd->offsets[i];

	if (obj->size < min_size) {
	drm_gem_object_unreference_unlocked(obj);
	ret = -EINVAL;
	goto err_gem_object_unreference;
	}
	objs[i] = to_drm_gem_cma_obj(obj);
	}

	fb_cma = drm_fb_cma_alloc(dev, mode_cmd, objs, i);
	if (IS_ERR(fb_cma)) {
	ret = PTR_ERR(fb_cma);
	goto err_gem_object_unreference;
	}

	return &fb_cma->fb;

	err_gem_object_unreference:
	for (i--; i >= 0; i--)
	drm_gem_object_unreference_unlocked(&objs[i]->base);
	return ERR_PTR(ret);
	}
	EXPORT_SYMBOL_GPL(drm_fb_cma_create);

	/**
	* drm_fb_cma_get_gem_obj() - Get CMA GEM object for framebuffer
	* @fb: The framebuffer
	* @plane: Which plane
	*
	* Return the CMA GEM object for given framebuffer.
	*
	* This function will usually be called from the CRTC callback functions.
	*/
	struct drm_gem_cma_object drm_fb_cma_get_gem_obj(struct drm_framebuffer fb,
	unsigned int plane)
	{
	struct drm_fb_cma *fb_cma = to_fb_cma(fb);

	if (plane >= 4)
	return NULL;

	return fb_cma->obj[plane];
	}
	EXPORT_SYMBOL_GPL(drm_fb_cma_get_gem_obj);

	#ifdef CONFIG_DEBUG_FS
	/*
	* drm_fb_cma_describe() - Helper to dump information about a single
	* CMA framebuffer object
	*/
	static void drm_fb_cma_describe(struct drm_framebuffer fb, struct seq_file m)
	{
	struct drm_fb_cma *fb_cma = to_fb_cma(fb);
	int i, n = drm_format_num_planes(fb->pixel_format);

	seq_printf(m, "fb: %dx%d@%4.4s\n", fb->width, fb->height,
	(char *)&fb->pixel_format);

	for (i = 0; i < n; i++) {
	seq_printf(m, " %d: offset=%d pitch=%d, obj: ",
	i, fb->offsets[i], fb->pitches[i]);
	drm_gem_cma_describe(fb_cma->obj[i], m);
	}
	}

	/**
	* drm_fb_cma_debugfs_show() - Helper to list CMA framebuffer objects
	* in debugfs.
	*/
	int drm_fb_cma_debugfs_show(struct seq_file m, void arg)
	{
	struct drm_info_node node = (struct drm_info_node ) m->private;
	struct drm_device *dev = node->minor->dev;
	struct drm_framebuffer *fb;

	mutex_lock(&dev->mode_config.fb_lock);
	drm_for_each_fb(fb, dev)
	drm_fb_cma_describe(fb, m);
	mutex_unlock(&dev->mode_config.fb_lock);

	return 0;
	}
	EXPORT_SYMBOL_GPL(drm_fb_cma_debugfs_show);
	#endif

	static struct fb_ops drm_fbdev_cma_ops = {
	.owner = THIS_MODULE,
	.fb_fillrect = drm_fb_helper_sys_fillrect,
	.fb_copyarea = drm_fb_helper_sys_copyarea,
	.fb_imageblit = drm_fb_helper_sys_imageblit,
	.fb_check_var = drm_fb_helper_check_var,
	.fb_set_par = drm_fb_helper_set_par,
	.fb_blank = drm_fb_helper_blank,
	.fb_pan_display = drm_fb_helper_pan_display,
	.fb_setcmap = drm_fb_helper_setcmap,
	};

	static int drm_fbdev_cma_create(struct drm_fb_helper *helper,
	struct drm_fb_helper_surface_size *sizes)
	{
	struct drm_fbdev_cma *fbdev_cma = to_fbdev_cma(helper);
	struct drm_mode_fb_cmd2 mode_cmd = { 0 };
	struct drm_device *dev = helper->dev;
	struct drm_gem_cma_object *obj;
	struct drm_framebuffer *fb;
	unsigned int bytes_per_pixel;
	unsigned long offset;
	struct fb_info *fbi;
	size_t size;
	int ret;

	DRM_DEBUG_KMS("surface width(%d), height(%d) and bpp(%d)\n",
	sizes->surface_width, sizes->surface_height,
	sizes->surface_bpp);

	bytes_per_pixel = DIV_ROUND_UP(sizes->surface_bpp, 8);

	mode_cmd.width = sizes->surface_width;
	mode_cmd.height = sizes->surface_height;
	mode_cmd.pitches[0] = sizes->surface_width * bytes_per_pixel;
	mode_cmd.pixel_format = drm_mode_legacy_fb_format(sizes->surface_bpp,
	sizes->surface_depth);

	size = mode_cmd.pitches[0] * mode_cmd.height;
	obj = drm_gem_cma_create(dev, size);
	if (IS_ERR(obj))
	return -ENOMEM;

	fbi = drm_fb_helper_alloc_fbi(helper);
	if (IS_ERR(fbi)) {
	ret = PTR_ERR(fbi);
	goto err_gem_free_object;
	}

	fbdev_cma->fb = drm_fb_cma_alloc(dev, &mode_cmd, &obj, 1);
	if (IS_ERR(fbdev_cma->fb)) {
	dev_err(dev->dev, "Failed to allocate DRM framebuffer.\n");
	ret = PTR_ERR(fbdev_cma->fb);
	goto err_fb_info_destroy;
	}

	fb = &fbdev_cma->fb->fb;
	helper->fb = fb;

	fbi->par = helper;
	fbi->flags = FBINFO_FLAG_DEFAULT;
	fbi->fbops = &drm_fbdev_cma_ops;

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

	offset = fbi->var.xoffset * bytes_per_pixel;
	offset += fbi->var.yoffset * fb->pitches[0];

	dev->mode_config.fb_base = (resource_size_t)obj->paddr;
	fbi->screen_base = obj->vaddr + offset;
	fbi->fix.smem_start = (unsigned long)(obj->paddr + offset);
	fbi->screen_size = size;
	fbi->fix.smem_len = size;

	return 0;

	err_fb_info_destroy:
	drm_fb_helper_release_fbi(helper);
	err_gem_free_object:
	dev->driver->gem_free_object(&obj->base);
	return ret;
	}

	static const struct drm_fb_helper_funcs drm_fb_cma_helper_funcs = {
	.fb_probe = drm_fbdev_cma_create,
	};

	/**
	* drm_fbdev_cma_init() - Allocate and initializes a drm_fbdev_cma struct
	* @dev: DRM device
	* @preferred_bpp: Preferred bits per pixel for the device
	* @num_crtc: Number of CRTCs
	* @max_conn_count: Maximum number of connectors
	*
	* Returns a newly allocated drm_fbdev_cma struct or a ERR_PTR.
	*/
	struct drm_fbdev_cma drm_fbdev_cma_init(struct drm_device dev,
	unsigned int preferred_bpp, unsigned int num_crtc,
	unsigned int max_conn_count)
	{
	struct drm_fbdev_cma *fbdev_cma;
	struct drm_fb_helper *helper;
	int ret;

	fbdev_cma = kzalloc(sizeof(*fbdev_cma), GFP_KERNEL);
	if (!fbdev_cma) {
	dev_err(dev->dev, "Failed to allocate drm fbdev.\n");
	return ERR_PTR(-ENOMEM);
	}

	helper = &fbdev_cma->fb_helper;

	drm_fb_helper_prepare(dev, helper, &drm_fb_cma_helper_funcs);

	ret = drm_fb_helper_init(dev, helper, num_crtc, max_conn_count);
	if (ret < 0) {
	dev_err(dev->dev, "Failed to initialize drm fb helper.\n");
	goto err_free;
	}

	ret = drm_fb_helper_single_add_all_connectors(helper);
	if (ret < 0) {
	dev_err(dev->dev, "Failed to add connectors.\n");
	goto err_drm_fb_helper_fini;

	}

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

	ret = drm_fb_helper_initial_config(helper, preferred_bpp);
	if (ret < 0) {
	dev_err(dev->dev, "Failed to set initial hw configuration.\n");
	goto err_drm_fb_helper_fini;
	}

	return fbdev_cma;

	err_drm_fb_helper_fini:
	drm_fb_helper_fini(helper);
	err_free:
	kfree(fbdev_cma);

	return ERR_PTR(ret);
	}
	EXPORT_SYMBOL_GPL(drm_fbdev_cma_init);

	/**
	* drm_fbdev_cma_fini() - Free drm_fbdev_cma struct
	* @fbdev_cma: The drm_fbdev_cma struct
	*/
	void drm_fbdev_cma_fini(struct drm_fbdev_cma *fbdev_cma)
	{
	drm_fb_helper_unregister_fbi(&fbdev_cma->fb_helper);
	drm_fb_helper_release_fbi(&fbdev_cma->fb_helper);

	if (fbdev_cma->fb) {
	drm_framebuffer_unregister_private(&fbdev_cma->fb->fb);
	drm_fb_cma_destroy(&fbdev_cma->fb->fb);
	}

	drm_fb_helper_fini(&fbdev_cma->fb_helper);
	kfree(fbdev_cma);
	}
	EXPORT_SYMBOL_GPL(drm_fbdev_cma_fini);

	/**
	* drm_fbdev_cma_restore_mode() - Restores initial framebuffer mode
	* @fbdev_cma: The drm_fbdev_cma struct, may be NULL
	*
	* This function is usually called from the DRM drivers lastclose callback.
	*/
	void drm_fbdev_cma_restore_mode(struct drm_fbdev_cma *fbdev_cma)
	{
	if (fbdev_cma)
	drm_fb_helper_restore_fbdev_mode_unlocked(&fbdev_cma->fb_helper);
	}
	EXPORT_SYMBOL_GPL(drm_fbdev_cma_restore_mode);

	/**
	* drm_fbdev_cma_hotplug_event() - Poll for hotpulug events
	* @fbdev_cma: The drm_fbdev_cma struct, may be NULL
	*
	* This function is usually called from the DRM drivers output_poll_changed
	* callback.
	*/
	void drm_fbdev_cma_hotplug_event(struct drm_fbdev_cma *fbdev_cma)
	{
	if (fbdev_cma)
	drm_fb_helper_hotplug_event(&fbdev_cma->fb_helper);
	}
	EXPORT_SYMBOL_GPL(drm_fbdev_cma_hotplug_event);