drivers/gpu/drm/udl/udl_fb.c - kernel/msm-4.9 - Gitiles

 /*
  * Copyright (C) 2012 Red Hat
  *
  * based in parts on udlfb.c:
  * Copyright (C) 2009 Roberto De Ioris <roberto@unbit.it>
  * Copyright (C) 2009 Jaya Kumar <jayakumar.lkml@gmail.com>
  * Copyright (C) 2009 Bernie Thompson <bernie@plugable.com>
  *
  * This file is subject to the terms and conditions of the GNU General Public
  * License v2. See the file COPYING in the main directory of this archive for
  * more details.
  */
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/fb.h>
 #include <linux/dma-buf.h>

 #include <drm/drmP.h>
 #include <drm/drm_crtc.h>
 #include <drm/drm_crtc_helper.h>
 #include "udl_drv.h"

 #include <drm/drm_fb_helper.h>

 #define DL_DEFIO_WRITE_DELAY    (HZ/20) /* fb_deferred_io.delay in jiffies */

 static int fb_defio = 0;  /* Optionally enable experimental fb_defio mmap support */
 static int fb_bpp = 16;

 module_param(fb_bpp, int, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
 module_param(fb_defio, int, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);

 struct udl_fbdev {
 	struct drm_fb_helper helper;
 	struct udl_framebuffer ufb;
 	struct list_head fbdev_list;
 	int fb_count;
 };

 #define DL_ALIGN_UP(x, a) ALIGN(x, a)
 #define DL_ALIGN_DOWN(x, a) ALIGN(x-(a-1), a)

 /** Read the red component (0..255) of a 32 bpp colour. */
 #define DLO_RGB_GETRED(col) (uint8_t)((col) & 0xFF)

 /** Read the green component (0..255) of a 32 bpp colour. */
 #define DLO_RGB_GETGRN(col) (uint8_t)(((col) >> 8) & 0xFF)

 /** Read the blue component (0..255) of a 32 bpp colour. */
 #define DLO_RGB_GETBLU(col) (uint8_t)(((col) >> 16) & 0xFF)

 /** Return red/green component of a 16 bpp colour number. */
 #define DLO_RG16(red, grn) (uint8_t)((((red) & 0xF8) | ((grn) >> 5)) & 0xFF)

 /** Return green/blue component of a 16 bpp colour number. */
 #define DLO_GB16(grn, blu) (uint8_t)(((((grn) & 0x1C) << 3) | ((blu) >> 3)) & 0xFF)

 /** Return 8 bpp colour number from red, green and blue components. */
 #define DLO_RGB8(red, grn, blu) ((((red) << 5) | (((grn) & 3) << 3) | ((blu) & 7)) & 0xFF)

 #if 0
 static uint8_t rgb8(uint32_t col)
 {
 	uint8_t red = DLO_RGB_GETRED(col);
 	uint8_t grn = DLO_RGB_GETGRN(col);
 	uint8_t blu = DLO_RGB_GETBLU(col);

 	return DLO_RGB8(red, grn, blu);
 }

 static uint16_t rgb16(uint32_t col)
 {
 	uint8_t red = DLO_RGB_GETRED(col);
 	uint8_t grn = DLO_RGB_GETGRN(col);
 	uint8_t blu = DLO_RGB_GETBLU(col);

 	return (DLO_RG16(red, grn) << 8) + DLO_GB16(grn, blu);
 }
 #endif

 /*
  * NOTE: fb_defio.c is holding info->fbdefio.mutex
  *   Touching ANY framebuffer memory that triggers a page fault
  *   in fb_defio will cause a deadlock, when it also tries to
  *   grab the same mutex.
  */
 static void udlfb_dpy_deferred_io(struct fb_info *info,
 				  struct list_head *pagelist)
 {
 	struct page *cur;
 	struct fb_deferred_io *fbdefio = info->fbdefio;
 	struct udl_fbdev *ufbdev = info->par;
 	struct drm_device *dev = ufbdev->ufb.base.dev;
 	struct udl_device *udl = dev->dev_private;
 	struct urb *urb;
 	char *cmd;
 	cycles_t start_cycles, end_cycles;
 	int bytes_sent = 0;
 	int bytes_identical = 0;
 	int bytes_rendered = 0;

 	if (!fb_defio)
 		return;

 	start_cycles = get_cycles();

 	urb = udl_get_urb(dev);
 	if (!urb)
 		return;

 	cmd = urb->transfer_buffer;

 	/* walk the written page list and render each to device */
 	list_for_each_entry(cur, &fbdefio->pagelist, lru) {

 		if (udl_render_hline(dev, (ufbdev->ufb.base.bits_per_pixel / 8),
 				     &urb, (char *) info->fix.smem_start,
 				     &cmd, cur->index << PAGE_SHIFT,
 				     cur->index << PAGE_SHIFT,
 				     PAGE_SIZE, &bytes_identical, &bytes_sent))
 			goto error;
 		bytes_rendered += PAGE_SIZE;
 	}

 	if (cmd > (char *) urb->transfer_buffer) {
 		/* Send partial buffer remaining before exiting */
 		int len = cmd - (char *) urb->transfer_buffer;
 		udl_submit_urb(dev, urb, len);
 		bytes_sent += len;
 	} else
 		udl_urb_completion(urb);

 error:
 	atomic_add(bytes_sent, &udl->bytes_sent);
 	atomic_add(bytes_identical, &udl->bytes_identical);
 	atomic_add(bytes_rendered, &udl->bytes_rendered);
 	end_cycles = get_cycles();
 	atomic_add(((unsigned int) ((end_cycles - start_cycles)
 		    >> 10)), /* Kcycles */
 		   &udl->cpu_kcycles_used);
 }

 int udl_handle_damage(struct udl_framebuffer *fb, int x, int y,
 		      int width, int height)
 {
 	struct drm_device *dev = fb->base.dev;
 	struct udl_device *udl = dev->dev_private;
 	int i, ret;
 	char *cmd;
 	cycles_t start_cycles, end_cycles;
 	int bytes_sent = 0;
 	int bytes_identical = 0;
 	struct urb *urb;
 	int aligned_x;
 	int bpp = (fb->base.bits_per_pixel / 8);
 	int x2, y2;
 	bool store_for_later = false;
 	unsigned long flags;

 	if (!fb->active_16)
 		return 0;

 	if (!fb->obj->vmapping) {
 		ret = udl_gem_vmap(fb->obj);
 		if (ret == -ENOMEM) {
 			DRM_ERROR("failed to vmap fb\n");
 			return 0;
 		}
 		if (!fb->obj->vmapping) {
 			DRM_ERROR("failed to vmapping\n");
 			return 0;
 		}
 	}

 	aligned_x = DL_ALIGN_DOWN(x, sizeof(unsigned long));
 	width = DL_ALIGN_UP(width + (x-aligned_x), sizeof(unsigned long));
 	x = aligned_x;

 	if ((width <= 0) ||
 	    (x + width > fb->base.width) ||
 	    (y + height > fb->base.height))
 		return -EINVAL;

 	/* if we are in atomic just store the info
 	   can't test inside spin lock */
 	if (in_atomic())
 		store_for_later = true;

 	x2 = x + width - 1;
 	y2 = y + height - 1;

 	spin_lock_irqsave(&fb->dirty_lock, flags);

 	if (fb->y1 < y)
 		y = fb->y1;
 	if (fb->y2 > y2)
 		y2 = fb->y2;
 	if (fb->x1 < x)
 		x = fb->x1;
 	if (fb->x2 > x2)
 		x2 = fb->x2;

 	if (store_for_later) {
 		fb->x1 = x;
 		fb->x2 = x2;
 		fb->y1 = y;
 		fb->y2 = y2;
 		spin_unlock_irqrestore(&fb->dirty_lock, flags);
 		return 0;
 	}

 	fb->x1 = fb->y1 = INT_MAX;
 	fb->x2 = fb->y2 = 0;

 	spin_unlock_irqrestore(&fb->dirty_lock, flags);
 	start_cycles = get_cycles();

 	urb = udl_get_urb(dev);
 	if (!urb)
 		return 0;
 	cmd = urb->transfer_buffer;

 	for (i = y; i <= y2 ; i++) {
 		const int line_offset = fb->base.pitches[0] * i;
 		const int byte_offset = line_offset + (x * bpp);
 		const int dev_byte_offset = (fb->base.width * bpp * i) + (x * bpp);
 		if (udl_render_hline(dev, bpp, &urb,
 				     (char *) fb->obj->vmapping,
 				     &cmd, byte_offset, dev_byte_offset,
 				     (x2 - x + 1) * bpp,
 				     &bytes_identical, &bytes_sent))
 			goto error;
 	}

 	if (cmd > (char *) urb->transfer_buffer) {
 		/* Send partial buffer remaining before exiting */
 		int len = cmd - (char *) urb->transfer_buffer;
 		ret = udl_submit_urb(dev, urb, len);
 		bytes_sent += len;
 	} else
 		udl_urb_completion(urb);

 error:
 	atomic_add(bytes_sent, &udl->bytes_sent);
 	atomic_add(bytes_identical, &udl->bytes_identical);
 	atomic_add(width*height*bpp, &udl->bytes_rendered);
 	end_cycles = get_cycles();
 	atomic_add(((unsigned int) ((end_cycles - start_cycles)
 		    >> 10)), /* Kcycles */
 		   &udl->cpu_kcycles_used);

 	return 0;
 }

 static int udl_fb_mmap(struct fb_info *info, struct vm_area_struct *vma)
 {
 	unsigned long start = vma->vm_start;
 	unsigned long size = vma->vm_end - vma->vm_start;
 	unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
 	unsigned long page, pos;

 	if (offset + size > info->fix.smem_len)
 		return -EINVAL;

 	pos = (unsigned long)info->fix.smem_start + offset;

 	pr_notice("mmap() framebuffer addr:%lu size:%lu\n",
 		  pos, size);

 	while (size > 0) {
 		page = vmalloc_to_pfn((void *)pos);
 		if (remap_pfn_range(vma, start, page, PAGE_SIZE, PAGE_SHARED))
 			return -EAGAIN;

 		start += PAGE_SIZE;
 		pos += PAGE_SIZE;
 		if (size > PAGE_SIZE)
 			size -= PAGE_SIZE;
 		else
 			size = 0;
 	}

 	/* VM_IO | VM_DONTEXPAND | VM_DONTDUMP are set by remap_pfn_range() */
 	return 0;
 }

 static void udl_fb_fillrect(struct fb_info *info, const struct fb_fillrect *rect)
 {
 	struct udl_fbdev *ufbdev = info->par;

 	sys_fillrect(info, rect);

 	udl_handle_damage(&ufbdev->ufb, rect->dx, rect->dy, rect->width,
 			  rect->height);
 }

 static void udl_fb_copyarea(struct fb_info *info, const struct fb_copyarea *region)
 {
 	struct udl_fbdev *ufbdev = info->par;

 	sys_copyarea(info, region);

 	udl_handle_damage(&ufbdev->ufb, region->dx, region->dy, region->width,
 			  region->height);
 }

 static void udl_fb_imageblit(struct fb_info *info, const struct fb_image *image)
 {
 	struct udl_fbdev *ufbdev = info->par;

 	sys_imageblit(info, image);

 	udl_handle_damage(&ufbdev->ufb, image->dx, image->dy, image->width,
 			  image->height);
 }

 /*
  * It's common for several clients to have framebuffer open simultaneously.
  * e.g. both fbcon and X. Makes things interesting.
  * Assumes caller is holding info->lock (for open and release at least)
  */
 static int udl_fb_open(struct fb_info *info, int user)
 {
 	struct udl_fbdev *ufbdev = info->par;
 	struct drm_device *dev = ufbdev->ufb.base.dev;
 	struct udl_device *udl = dev->dev_private;

 	/* If the USB device is gone, we don't accept new opens */
 	if (drm_device_is_unplugged(udl->ddev))
 		return -ENODEV;

 	ufbdev->fb_count++;

 	if (fb_defio && (info->fbdefio == NULL)) {
 		/* enable defio at last moment if not disabled by client */

 		struct fb_deferred_io *fbdefio;

 		fbdefio = kmalloc(sizeof(struct fb_deferred_io), GFP_KERNEL);

 		if (fbdefio) {
 			fbdefio->delay = DL_DEFIO_WRITE_DELAY;
 			fbdefio->deferred_io = udlfb_dpy_deferred_io;
 		}

 		info->fbdefio = fbdefio;
 		fb_deferred_io_init(info);
 	}

 	pr_notice("open /dev/fb%d user=%d fb_info=%p count=%d\n",
 		  info->node, user, info, ufbdev->fb_count);

 	return 0;
 }


 /*
  * Assumes caller is holding info->lock mutex (for open and release at least)
  */
 static int udl_fb_release(struct fb_info *info, int user)
 {
 	struct udl_fbdev *ufbdev = info->par;

 	ufbdev->fb_count--;

 	if ((ufbdev->fb_count == 0) && (info->fbdefio)) {
 		fb_deferred_io_cleanup(info);
 		kfree(info->fbdefio);
 		info->fbdefio = NULL;
 		info->fbops->fb_mmap = udl_fb_mmap;
 	}

 	pr_warn("released /dev/fb%d user=%d count=%d\n",
 		info->node, user, ufbdev->fb_count);

 	return 0;
 }

 static struct fb_ops udlfb_ops = {
 	.owner = THIS_MODULE,
 	.fb_check_var = drm_fb_helper_check_var,
 	.fb_set_par = drm_fb_helper_set_par,
 	.fb_fillrect = udl_fb_fillrect,
 	.fb_copyarea = udl_fb_copyarea,
 	.fb_imageblit = udl_fb_imageblit,
 	.fb_pan_display = drm_fb_helper_pan_display,
 	.fb_blank = drm_fb_helper_blank,
 	.fb_setcmap = drm_fb_helper_setcmap,
 	.fb_debug_enter = drm_fb_helper_debug_enter,
 	.fb_debug_leave = drm_fb_helper_debug_leave,
 	.fb_mmap = udl_fb_mmap,
 	.fb_open = udl_fb_open,
 	.fb_release = udl_fb_release,
 };

 static int udl_user_framebuffer_dirty(struct drm_framebuffer *fb,
 				      struct drm_file *file,
 				      unsigned flags, unsigned color,
 				      struct drm_clip_rect *clips,
 				      unsigned num_clips)
 {
 	struct udl_framebuffer *ufb = to_udl_fb(fb);
 	int i;
 	int ret = 0;

 	drm_modeset_lock_all(fb->dev);

 	if (!ufb->active_16)
 		goto unlock;

 	if (ufb->obj->base.import_attach) {
 		ret = dma_buf_begin_cpu_access(ufb->obj->base.import_attach->dmabuf,
 					       0, ufb->obj->base.size,
 					       DMA_FROM_DEVICE);
 		if (ret)
 			goto unlock;
 	}

 	for (i = 0; i < num_clips; i++) {
 		ret = udl_handle_damage(ufb, clips[i].x1, clips[i].y1,
 				  clips[i].x2 - clips[i].x1,
 				  clips[i].y2 - clips[i].y1);
 		if (ret)
 			break;
 	}

 	if (ufb->obj->base.import_attach) {
 		dma_buf_end_cpu_access(ufb->obj->base.import_attach->dmabuf,
 				       0, ufb->obj->base.size,
 				       DMA_FROM_DEVICE);
 	}

  unlock:
 	drm_modeset_unlock_all(fb->dev);

 	return ret;
 }

 static void udl_user_framebuffer_destroy(struct drm_framebuffer *fb)
 {
 	struct udl_framebuffer *ufb = to_udl_fb(fb);

 	if (ufb->obj)
 		drm_gem_object_unreference_unlocked(&ufb->obj->base);

 	drm_framebuffer_cleanup(fb);
 	kfree(ufb);
 }

 static const struct drm_framebuffer_funcs udlfb_funcs = {
 	.destroy = udl_user_framebuffer_destroy,
 	.dirty = udl_user_framebuffer_dirty,
 };


 static int
 udl_framebuffer_init(struct drm_device *dev,
 		     struct udl_framebuffer *ufb,
 		     struct drm_mode_fb_cmd2 *mode_cmd,
 		     struct udl_gem_object *obj)
 {
 	int ret;

 	spin_lock_init(&ufb->dirty_lock);
 	ufb->obj = obj;
 	drm_helper_mode_fill_fb_struct(&ufb->base, mode_cmd);
 	ret = drm_framebuffer_init(dev, &ufb->base, &udlfb_funcs);
 	return ret;
 }


 static int udlfb_create(struct drm_fb_helper *helper,
 			struct drm_fb_helper_surface_size *sizes)
 {
 	struct udl_fbdev *ufbdev = (struct udl_fbdev *)helper;
 	struct drm_device *dev = ufbdev->helper.dev;
 	struct fb_info *info;
 	struct device *device = dev->dev;
 	struct drm_framebuffer *fb;
 	struct drm_mode_fb_cmd2 mode_cmd;
 	struct udl_gem_object *obj;
 	uint32_t size;
 	int ret = 0;

 	if (sizes->surface_bpp == 24)
 		sizes->surface_bpp = 32;

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

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

 	size = mode_cmd.pitches[0] * mode_cmd.height;
 	size = ALIGN(size, PAGE_SIZE);

 	obj = udl_gem_alloc_object(dev, size);
 	if (!obj)
 		goto out;

 	ret = udl_gem_vmap(obj);
 	if (ret) {
 		DRM_ERROR("failed to vmap fb\n");
 		goto out_gfree;
 	}

 	info = framebuffer_alloc(0, device);
 	if (!info) {
 		ret = -ENOMEM;
 		goto out_gfree;
 	}
 	info->par = ufbdev;

 	ret = udl_framebuffer_init(dev, &ufbdev->ufb, &mode_cmd, obj);
 	if (ret)
 		goto out_gfree;

 	fb = &ufbdev->ufb.base;

 	ufbdev->helper.fb = fb;
 	ufbdev->helper.fbdev = info;

 	strcpy(info->fix.id, "udldrmfb");

 	info->screen_base = ufbdev->ufb.obj->vmapping;
 	info->fix.smem_len = size;
 	info->fix.smem_start = (unsigned long)ufbdev->ufb.obj->vmapping;

 	info->flags = FBINFO_DEFAULT | FBINFO_CAN_FORCE_OUTPUT;
 	info->fbops = &udlfb_ops;
 	drm_fb_helper_fill_fix(info, fb->pitches[0], fb->depth);
 	drm_fb_helper_fill_var(info, &ufbdev->helper, sizes->fb_width, sizes->fb_height);

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


 	DRM_DEBUG_KMS("allocated %dx%d vmal %p\n",
 		      fb->width, fb->height,
 		      ufbdev->ufb.obj->vmapping);

 	return ret;
 out_gfree:
 	drm_gem_object_unreference(&ufbdev->ufb.obj->base);
 out:
 	return ret;
 }

 static struct drm_fb_helper_funcs udl_fb_helper_funcs = {
 	.fb_probe = udlfb_create,
 };

 static void udl_fbdev_destroy(struct drm_device *dev,
 			      struct udl_fbdev *ufbdev)
 {
 	struct fb_info *info;
 	if (ufbdev->helper.fbdev) {
 		info = ufbdev->helper.fbdev;
 		unregister_framebuffer(info);
 		if (info->cmap.len)
 			fb_dealloc_cmap(&info->cmap);
 		framebuffer_release(info);
 	}
 	drm_fb_helper_fini(&ufbdev->helper);
 	drm_framebuffer_unregister_private(&ufbdev->ufb.base);
 	drm_framebuffer_cleanup(&ufbdev->ufb.base);
 	drm_gem_object_unreference_unlocked(&ufbdev->ufb.obj->base);
 }

 int udl_fbdev_init(struct drm_device *dev)
 {
 	struct udl_device *udl = dev->dev_private;
 	int bpp_sel = fb_bpp;
 	struct udl_fbdev *ufbdev;
 	int ret;

 	ufbdev = kzalloc(sizeof(struct udl_fbdev), GFP_KERNEL);
 	if (!ufbdev)
 		return -ENOMEM;

 	udl->fbdev = ufbdev;
 	ufbdev->helper.funcs = &udl_fb_helper_funcs;

 	ret = drm_fb_helper_init(dev, &ufbdev->helper,
 				 1, 1);
 	if (ret) {
 		kfree(ufbdev);
 		return ret;

 	}

 	drm_fb_helper_single_add_all_connectors(&ufbdev->helper);

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

 	drm_fb_helper_initial_config(&ufbdev->helper, bpp_sel);
 	return 0;
 }

 void udl_fbdev_cleanup(struct drm_device *dev)
 {
 	struct udl_device *udl = dev->dev_private;
 	if (!udl->fbdev)
 		return;

 	udl_fbdev_destroy(dev, udl->fbdev);
 	kfree(udl->fbdev);
 	udl->fbdev = NULL;
 }

 void udl_fbdev_unplug(struct drm_device *dev)
 {
 	struct udl_device *udl = dev->dev_private;
 	struct udl_fbdev *ufbdev;
 	if (!udl->fbdev)
 		return;

 	ufbdev = udl->fbdev;
 	if (ufbdev->helper.fbdev) {
 		struct fb_info *info;
 		info = ufbdev->helper.fbdev;
 		unlink_framebuffer(info);
 	}
 }

 struct drm_framebuffer *
 udl_fb_user_fb_create(struct drm_device *dev,
 		   struct drm_file *file,
 		   struct drm_mode_fb_cmd2 *mode_cmd)
 {
 	struct drm_gem_object *obj;
 	struct udl_framebuffer *ufb;
 	int ret;
 	uint32_t size;

 	obj = drm_gem_object_lookup(dev, file, mode_cmd->handles[0]);
 	if (obj == NULL)
 		return ERR_PTR(-ENOENT);

 	size = mode_cmd->pitches[0] * mode_cmd->height;
 	size = ALIGN(size, PAGE_SIZE);

 	if (size > obj->size) {
 		DRM_ERROR("object size not sufficient for fb %d %zu %d %d\n", size, obj->size, mode_cmd->pitches[0], mode_cmd->height);
 		return ERR_PTR(-ENOMEM);
 	}

 	ufb = kzalloc(sizeof(*ufb), GFP_KERNEL);
 	if (ufb == NULL)
 		return ERR_PTR(-ENOMEM);

 	ret = udl_framebuffer_init(dev, ufb, mode_cmd, to_udl_bo(obj));
 	if (ret) {
 		kfree(ufb);
 		return ERR_PTR(-EINVAL);
 	}
 	return &ufb->base;
 }
	/*
	* Copyright (C) 2012 Red Hat
	*
	* based in parts on udlfb.c:
	* Copyright (C) 2009 Roberto De Ioris <roberto@unbit.it>
	* Copyright (C) 2009 Jaya Kumar <jayakumar.lkml@gmail.com>
	* Copyright (C) 2009 Bernie Thompson <bernie@plugable.com>
	*
	* This file is subject to the terms and conditions of the GNU General Public
	* License v2. See the file COPYING in the main directory of this archive for
	* more details.
	*/
	#include <linux/module.h>
	#include <linux/slab.h>
	#include <linux/fb.h>
	#include <linux/dma-buf.h>

	#include <drm/drmP.h>
	#include <drm/drm_crtc.h>
	#include <drm/drm_crtc_helper.h>
	#include "udl_drv.h"

	#include <drm/drm_fb_helper.h>

	#define DL_DEFIO_WRITE_DELAY (HZ/20) /* fb_deferred_io.delay in jiffies */

	static int fb_defio = 0; /* Optionally enable experimental fb_defio mmap support */
	static int fb_bpp = 16;

	module_param(fb_bpp, int, S_IWUSR \| S_IRUSR \| S_IWGRP \| S_IRGRP);
	module_param(fb_defio, int, S_IWUSR \| S_IRUSR \| S_IWGRP \| S_IRGRP);

	struct udl_fbdev {
	struct drm_fb_helper helper;
	struct udl_framebuffer ufb;
	struct list_head fbdev_list;
	int fb_count;
	};

	#define DL_ALIGN_UP(x, a) ALIGN(x, a)
	#define DL_ALIGN_DOWN(x, a) ALIGN(x-(a-1), a)

	/** Read the red component (0..255) of a 32 bpp colour. */
	#define DLO_RGB_GETRED(col) (uint8_t)((col) & 0xFF)

	/** Read the green component (0..255) of a 32 bpp colour. */
	#define DLO_RGB_GETGRN(col) (uint8_t)(((col) >> 8) & 0xFF)

	/** Read the blue component (0..255) of a 32 bpp colour. */
	#define DLO_RGB_GETBLU(col) (uint8_t)(((col) >> 16) & 0xFF)

	/** Return red/green component of a 16 bpp colour number. */
	#define DLO_RG16(red, grn) (uint8_t)((((red) & 0xF8) \| ((grn) >> 5)) & 0xFF)

	/** Return green/blue component of a 16 bpp colour number. */
	#define DLO_GB16(grn, blu) (uint8_t)(((((grn) & 0x1C) << 3) \| ((blu) >> 3)) & 0xFF)

	/** Return 8 bpp colour number from red, green and blue components. */
	#define DLO_RGB8(red, grn, blu) ((((red) << 5) \| (((grn) & 3) << 3) \| ((blu) & 7)) & 0xFF)

	#if 0
	static uint8_t rgb8(uint32_t col)
	{
	uint8_t red = DLO_RGB_GETRED(col);
	uint8_t grn = DLO_RGB_GETGRN(col);
	uint8_t blu = DLO_RGB_GETBLU(col);

	return DLO_RGB8(red, grn, blu);
	}

	static uint16_t rgb16(uint32_t col)
	{
	uint8_t red = DLO_RGB_GETRED(col);
	uint8_t grn = DLO_RGB_GETGRN(col);
	uint8_t blu = DLO_RGB_GETBLU(col);

	return (DLO_RG16(red, grn) << 8) + DLO_GB16(grn, blu);
	}
	#endif

	/*
	* NOTE: fb_defio.c is holding info->fbdefio.mutex
	* Touching ANY framebuffer memory that triggers a page fault
	* in fb_defio will cause a deadlock, when it also tries to
	* grab the same mutex.
	*/
	static void udlfb_dpy_deferred_io(struct fb_info *info,
	struct list_head *pagelist)
	{
	struct page *cur;
	struct fb_deferred_io *fbdefio = info->fbdefio;
	struct udl_fbdev *ufbdev = info->par;
	struct drm_device *dev = ufbdev->ufb.base.dev;
	struct udl_device *udl = dev->dev_private;
	struct urb *urb;
	char *cmd;
	cycles_t start_cycles, end_cycles;
	int bytes_sent = 0;
	int bytes_identical = 0;
	int bytes_rendered = 0;

	if (!fb_defio)
	return;

	start_cycles = get_cycles();

	urb = udl_get_urb(dev);
	if (!urb)
	return;

	cmd = urb->transfer_buffer;

	/* walk the written page list and render each to device */
	list_for_each_entry(cur, &fbdefio->pagelist, lru) {

	if (udl_render_hline(dev, (ufbdev->ufb.base.bits_per_pixel / 8),
	&urb, (char *) info->fix.smem_start,
	&cmd, cur->index << PAGE_SHIFT,
	cur->index << PAGE_SHIFT,
	PAGE_SIZE, &bytes_identical, &bytes_sent))
	goto error;
	bytes_rendered += PAGE_SIZE;
	}

	if (cmd > (char *) urb->transfer_buffer) {
	/* Send partial buffer remaining before exiting */
	int len = cmd - (char *) urb->transfer_buffer;
	udl_submit_urb(dev, urb, len);
	bytes_sent += len;
	} else
	udl_urb_completion(urb);

	error:
	atomic_add(bytes_sent, &udl->bytes_sent);
	atomic_add(bytes_identical, &udl->bytes_identical);
	atomic_add(bytes_rendered, &udl->bytes_rendered);
	end_cycles = get_cycles();
	atomic_add(((unsigned int) ((end_cycles - start_cycles)
	>> 10)), /* Kcycles */
	&udl->cpu_kcycles_used);
	}

	int udl_handle_damage(struct udl_framebuffer *fb, int x, int y,
	int width, int height)
	{
	struct drm_device *dev = fb->base.dev;
	struct udl_device *udl = dev->dev_private;
	int i, ret;
	char *cmd;
	cycles_t start_cycles, end_cycles;
	int bytes_sent = 0;
	int bytes_identical = 0;
	struct urb *urb;
	int aligned_x;
	int bpp = (fb->base.bits_per_pixel / 8);
	int x2, y2;
	bool store_for_later = false;
	unsigned long flags;

	if (!fb->active_16)
	return 0;

	if (!fb->obj->vmapping) {
	ret = udl_gem_vmap(fb->obj);
	if (ret == -ENOMEM) {
	DRM_ERROR("failed to vmap fb\n");
	return 0;
	}
	if (!fb->obj->vmapping) {
	DRM_ERROR("failed to vmapping\n");
	return 0;
	}
	}

	aligned_x = DL_ALIGN_DOWN(x, sizeof(unsigned long));
	width = DL_ALIGN_UP(width + (x-aligned_x), sizeof(unsigned long));
	x = aligned_x;

	if ((width <= 0) \|\|
	(x + width > fb->base.width) \|\|
	(y + height > fb->base.height))
	return -EINVAL;

	/* if we are in atomic just store the info
	can't test inside spin lock */
	if (in_atomic())
	store_for_later = true;

	x2 = x + width - 1;
	y2 = y + height - 1;

	spin_lock_irqsave(&fb->dirty_lock, flags);

	if (fb->y1 < y)
	y = fb->y1;
	if (fb->y2 > y2)
	y2 = fb->y2;
	if (fb->x1 < x)
	x = fb->x1;
	if (fb->x2 > x2)
	x2 = fb->x2;

	if (store_for_later) {
	fb->x1 = x;
	fb->x2 = x2;
	fb->y1 = y;
	fb->y2 = y2;
	spin_unlock_irqrestore(&fb->dirty_lock, flags);
	return 0;
	}

	fb->x1 = fb->y1 = INT_MAX;
	fb->x2 = fb->y2 = 0;

	spin_unlock_irqrestore(&fb->dirty_lock, flags);
	start_cycles = get_cycles();

	urb = udl_get_urb(dev);
	if (!urb)
	return 0;
	cmd = urb->transfer_buffer;

	for (i = y; i <= y2 ; i++) {
	const int line_offset = fb->base.pitches[0] * i;
	const int byte_offset = line_offset + (x * bpp);
	const int dev_byte_offset = (fb->base.width * bpp * i) + (x * bpp);
	if (udl_render_hline(dev, bpp, &urb,
	(char *) fb->obj->vmapping,
	&cmd, byte_offset, dev_byte_offset,
	(x2 - x + 1) * bpp,
	&bytes_identical, &bytes_sent))
	goto error;
	}

	if (cmd > (char *) urb->transfer_buffer) {
	/* Send partial buffer remaining before exiting */
	int len = cmd - (char *) urb->transfer_buffer;
	ret = udl_submit_urb(dev, urb, len);
	bytes_sent += len;
	} else
	udl_urb_completion(urb);

	error:
	atomic_add(bytes_sent, &udl->bytes_sent);
	atomic_add(bytes_identical, &udl->bytes_identical);
	atomic_add(widthheightbpp, &udl->bytes_rendered);
	end_cycles = get_cycles();
	atomic_add(((unsigned int) ((end_cycles - start_cycles)
	>> 10)), /* Kcycles */
	&udl->cpu_kcycles_used);

	return 0;
	}

	static int udl_fb_mmap(struct fb_info info, struct vm_area_struct vma)
	{
	unsigned long start = vma->vm_start;
	unsigned long size = vma->vm_end - vma->vm_start;
	unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
	unsigned long page, pos;

	if (offset + size > info->fix.smem_len)
	return -EINVAL;

	pos = (unsigned long)info->fix.smem_start + offset;

	pr_notice("mmap() framebuffer addr:%lu size:%lu\n",
	pos, size);

	while (size > 0) {
	page = vmalloc_to_pfn((void *)pos);
	if (remap_pfn_range(vma, start, page, PAGE_SIZE, PAGE_SHARED))
	return -EAGAIN;

	start += PAGE_SIZE;
	pos += PAGE_SIZE;
	if (size > PAGE_SIZE)
	size -= PAGE_SIZE;
	else
	size = 0;
	}

	/* VM_IO \| VM_DONTEXPAND \| VM_DONTDUMP are set by remap_pfn_range() */
	return 0;
	}

	static void udl_fb_fillrect(struct fb_info info, const struct fb_fillrect rect)
	{
	struct udl_fbdev *ufbdev = info->par;

	sys_fillrect(info, rect);

	udl_handle_damage(&ufbdev->ufb, rect->dx, rect->dy, rect->width,
	rect->height);
	}

	static void udl_fb_copyarea(struct fb_info info, const struct fb_copyarea region)
	{
	struct udl_fbdev *ufbdev = info->par;

	sys_copyarea(info, region);

	udl_handle_damage(&ufbdev->ufb, region->dx, region->dy, region->width,
	region->height);
	}

	static void udl_fb_imageblit(struct fb_info info, const struct fb_image image)
	{
	struct udl_fbdev *ufbdev = info->par;

	sys_imageblit(info, image);

	udl_handle_damage(&ufbdev->ufb, image->dx, image->dy, image->width,
	image->height);
	}

	/*
	* It's common for several clients to have framebuffer open simultaneously.
	* e.g. both fbcon and X. Makes things interesting.
	* Assumes caller is holding info->lock (for open and release at least)
	*/
	static int udl_fb_open(struct fb_info *info, int user)
	{
	struct udl_fbdev *ufbdev = info->par;
	struct drm_device *dev = ufbdev->ufb.base.dev;
	struct udl_device *udl = dev->dev_private;

	/* If the USB device is gone, we don't accept new opens */
	if (drm_device_is_unplugged(udl->ddev))
	return -ENODEV;

	ufbdev->fb_count++;

	if (fb_defio && (info->fbdefio == NULL)) {
	/* enable defio at last moment if not disabled by client */

	struct fb_deferred_io *fbdefio;

	fbdefio = kmalloc(sizeof(struct fb_deferred_io), GFP_KERNEL);

	if (fbdefio) {
	fbdefio->delay = DL_DEFIO_WRITE_DELAY;
	fbdefio->deferred_io = udlfb_dpy_deferred_io;
	}

	info->fbdefio = fbdefio;
	fb_deferred_io_init(info);
	}

	pr_notice("open /dev/fb%d user=%d fb_info=%p count=%d\n",
	info->node, user, info, ufbdev->fb_count);

	return 0;
	}


	/*
	* Assumes caller is holding info->lock mutex (for open and release at least)
	*/
	static int udl_fb_release(struct fb_info *info, int user)
	{
	struct udl_fbdev *ufbdev = info->par;

	ufbdev->fb_count--;

	if ((ufbdev->fb_count == 0) && (info->fbdefio)) {
	fb_deferred_io_cleanup(info);
	kfree(info->fbdefio);
	info->fbdefio = NULL;
	info->fbops->fb_mmap = udl_fb_mmap;
	}

	pr_warn("released /dev/fb%d user=%d count=%d\n",
	info->node, user, ufbdev->fb_count);

	return 0;
	}

	static struct fb_ops udlfb_ops = {
	.owner = THIS_MODULE,
	.fb_check_var = drm_fb_helper_check_var,
	.fb_set_par = drm_fb_helper_set_par,
	.fb_fillrect = udl_fb_fillrect,
	.fb_copyarea = udl_fb_copyarea,
	.fb_imageblit = udl_fb_imageblit,
	.fb_pan_display = drm_fb_helper_pan_display,
	.fb_blank = drm_fb_helper_blank,
	.fb_setcmap = drm_fb_helper_setcmap,
	.fb_debug_enter = drm_fb_helper_debug_enter,
	.fb_debug_leave = drm_fb_helper_debug_leave,
	.fb_mmap = udl_fb_mmap,
	.fb_open = udl_fb_open,
	.fb_release = udl_fb_release,
	};

	static int udl_user_framebuffer_dirty(struct drm_framebuffer *fb,
	struct drm_file *file,
	unsigned flags, unsigned color,
	struct drm_clip_rect *clips,
	unsigned num_clips)
	{
	struct udl_framebuffer *ufb = to_udl_fb(fb);
	int i;
	int ret = 0;

	drm_modeset_lock_all(fb->dev);

	if (!ufb->active_16)
	goto unlock;

	if (ufb->obj->base.import_attach) {
	ret = dma_buf_begin_cpu_access(ufb->obj->base.import_attach->dmabuf,
	0, ufb->obj->base.size,
	DMA_FROM_DEVICE);
	if (ret)
	goto unlock;
	}

	for (i = 0; i < num_clips; i++) {
	ret = udl_handle_damage(ufb, clips[i].x1, clips[i].y1,
	clips[i].x2 - clips[i].x1,
	clips[i].y2 - clips[i].y1);
	if (ret)
	break;
	}

	if (ufb->obj->base.import_attach) {
	dma_buf_end_cpu_access(ufb->obj->base.import_attach->dmabuf,
	0, ufb->obj->base.size,
	DMA_FROM_DEVICE);
	}

	unlock:
	drm_modeset_unlock_all(fb->dev);

	return ret;
	}

	static void udl_user_framebuffer_destroy(struct drm_framebuffer *fb)
	{
	struct udl_framebuffer *ufb = to_udl_fb(fb);

	if (ufb->obj)
	drm_gem_object_unreference_unlocked(&ufb->obj->base);

	drm_framebuffer_cleanup(fb);
	kfree(ufb);
	}

	static const struct drm_framebuffer_funcs udlfb_funcs = {
	.destroy = udl_user_framebuffer_destroy,
	.dirty = udl_user_framebuffer_dirty,
	};


	static int
	udl_framebuffer_init(struct drm_device *dev,
	struct udl_framebuffer *ufb,
	struct drm_mode_fb_cmd2 *mode_cmd,
	struct udl_gem_object *obj)
	{
	int ret;

	spin_lock_init(&ufb->dirty_lock);
	ufb->obj = obj;
	drm_helper_mode_fill_fb_struct(&ufb->base, mode_cmd);
	ret = drm_framebuffer_init(dev, &ufb->base, &udlfb_funcs);
	return ret;
	}


	static int udlfb_create(struct drm_fb_helper *helper,
	struct drm_fb_helper_surface_size *sizes)
	{
	struct udl_fbdev ufbdev = (struct udl_fbdev )helper;
	struct drm_device *dev = ufbdev->helper.dev;
	struct fb_info *info;
	struct device *device = dev->dev;
	struct drm_framebuffer *fb;
	struct drm_mode_fb_cmd2 mode_cmd;
	struct udl_gem_object *obj;
	uint32_t size;
	int ret = 0;

	if (sizes->surface_bpp == 24)
	sizes->surface_bpp = 32;

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

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

	size = mode_cmd.pitches[0] * mode_cmd.height;
	size = ALIGN(size, PAGE_SIZE);

	obj = udl_gem_alloc_object(dev, size);
	if (!obj)
	goto out;

	ret = udl_gem_vmap(obj);
	if (ret) {
	DRM_ERROR("failed to vmap fb\n");
	goto out_gfree;
	}

	info = framebuffer_alloc(0, device);
	if (!info) {
	ret = -ENOMEM;
	goto out_gfree;
	}
	info->par = ufbdev;

	ret = udl_framebuffer_init(dev, &ufbdev->ufb, &mode_cmd, obj);
	if (ret)
	goto out_gfree;

	fb = &ufbdev->ufb.base;

	ufbdev->helper.fb = fb;
	ufbdev->helper.fbdev = info;

	strcpy(info->fix.id, "udldrmfb");

	info->screen_base = ufbdev->ufb.obj->vmapping;
	info->fix.smem_len = size;
	info->fix.smem_start = (unsigned long)ufbdev->ufb.obj->vmapping;

	info->flags = FBINFO_DEFAULT \| FBINFO_CAN_FORCE_OUTPUT;
	info->fbops = &udlfb_ops;
	drm_fb_helper_fill_fix(info, fb->pitches[0], fb->depth);
	drm_fb_helper_fill_var(info, &ufbdev->helper, sizes->fb_width, sizes->fb_height);

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


	DRM_DEBUG_KMS("allocated %dx%d vmal %p\n",
	fb->width, fb->height,
	ufbdev->ufb.obj->vmapping);

	return ret;
	out_gfree:
	drm_gem_object_unreference(&ufbdev->ufb.obj->base);
	out:
	return ret;
	}

	static struct drm_fb_helper_funcs udl_fb_helper_funcs = {
	.fb_probe = udlfb_create,
	};

	static void udl_fbdev_destroy(struct drm_device *dev,
	struct udl_fbdev *ufbdev)
	{
	struct fb_info *info;
	if (ufbdev->helper.fbdev) {
	info = ufbdev->helper.fbdev;
	unregister_framebuffer(info);
	if (info->cmap.len)
	fb_dealloc_cmap(&info->cmap);
	framebuffer_release(info);
	}
	drm_fb_helper_fini(&ufbdev->helper);
	drm_framebuffer_unregister_private(&ufbdev->ufb.base);
	drm_framebuffer_cleanup(&ufbdev->ufb.base);
	drm_gem_object_unreference_unlocked(&ufbdev->ufb.obj->base);
	}

	int udl_fbdev_init(struct drm_device *dev)
	{
	struct udl_device *udl = dev->dev_private;
	int bpp_sel = fb_bpp;
	struct udl_fbdev *ufbdev;
	int ret;

	ufbdev = kzalloc(sizeof(struct udl_fbdev), GFP_KERNEL);
	if (!ufbdev)
	return -ENOMEM;

	udl->fbdev = ufbdev;
	ufbdev->helper.funcs = &udl_fb_helper_funcs;

	ret = drm_fb_helper_init(dev, &ufbdev->helper,
	1, 1);
	if (ret) {
	kfree(ufbdev);
	return ret;

	}

	drm_fb_helper_single_add_all_connectors(&ufbdev->helper);

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

	drm_fb_helper_initial_config(&ufbdev->helper, bpp_sel);
	return 0;
	}

	void udl_fbdev_cleanup(struct drm_device *dev)
	{
	struct udl_device *udl = dev->dev_private;
	if (!udl->fbdev)
	return;

	udl_fbdev_destroy(dev, udl->fbdev);
	kfree(udl->fbdev);
	udl->fbdev = NULL;
	}

	void udl_fbdev_unplug(struct drm_device *dev)
	{
	struct udl_device *udl = dev->dev_private;
	struct udl_fbdev *ufbdev;
	if (!udl->fbdev)
	return;

	ufbdev = udl->fbdev;
	if (ufbdev->helper.fbdev) {
	struct fb_info *info;
	info = ufbdev->helper.fbdev;
	unlink_framebuffer(info);
	}
	}

	struct drm_framebuffer *
	udl_fb_user_fb_create(struct drm_device *dev,
	struct drm_file *file,
	struct drm_mode_fb_cmd2 *mode_cmd)
	{
	struct drm_gem_object *obj;
	struct udl_framebuffer *ufb;
	int ret;
	uint32_t size;

	obj = drm_gem_object_lookup(dev, file, mode_cmd->handles[0]);
	if (obj == NULL)
	return ERR_PTR(-ENOENT);

	size = mode_cmd->pitches[0] * mode_cmd->height;
	size = ALIGN(size, PAGE_SIZE);

	if (size > obj->size) {
	DRM_ERROR("object size not sufficient for fb %d %zu %d %d\n", size, obj->size, mode_cmd->pitches[0], mode_cmd->height);
	return ERR_PTR(-ENOMEM);
	}

	ufb = kzalloc(sizeof(*ufb), GFP_KERNEL);
	if (ufb == NULL)
	return ERR_PTR(-ENOMEM);

	ret = udl_framebuffer_init(dev, ufb, mode_cmd, to_udl_bo(obj));
	if (ret) {
	kfree(ufb);
	return ERR_PTR(-EINVAL);
	}
	return &ufb->base;
	}