[PATCH 04/05] video: deferred io sys helpers - metronome V2

[Magnus Damm <magnus.damm@gmail.com>]

From: Magnus Damm <damm@igel.co.jp>

Change the metronome driver to use the new shared sys helpers. This
allows us to remove some duplicated code. The use of the new shared
sys helpers will change the behavior of this driver from syncing all
fillrect/copyarea/imageblit/write operations directly to using the
deferred io delay.

Signed-off-by: Magnus Damm <damm@igel.co.jp>
---

 Changes since V1:
 - added dirty area update comment

 drivers/video/Kconfig       |    4 -
 drivers/video/metronomefb.c |  109 +++++++++----------------------------------
 2 files changed, 24 insertions(+), 89 deletions(-)

--- 0004/drivers/video/Kconfig
+++ work/drivers/video/Kconfig	2008-12-24 16:33:39.000000000 +0900
@@ -2071,10 +2071,6 @@ config XEN_FBDEV_FRONTEND
 config FB_METRONOME
 	tristate "E-Ink Metronome/8track controller support"
 	depends on FB
-	select FB_SYS_FILLRECT
-	select FB_SYS_COPYAREA
-	select FB_SYS_IMAGEBLIT
-	select FB_SYS_FOPS
 	select FB_DEFERRED_IO
 	help
 	  This driver implements support for the E-Ink Metronome
--- 0001/drivers/video/metronomefb.c
+++ work/drivers/video/metronomefb.c	2008-12-24 16:41:55.000000000 +0900
@@ -445,7 +445,6 @@ static void metronomefb_dpy_update(struc
 
 	cksum = calc_img_cksum((u16 *) par->metromem_img, fbsize/2);
 	*((u16 *)(par->metromem_img) + fbsize/2) = cksum;
-	metronome_display_cmd(par);
 }
 
 static u16 metronomefb_dpy_update_page(struct metronomefb_par *par, int index)
@@ -472,97 +471,37 @@ static void metronomefb_dpy_deferred_io(
 	struct fb_deferred_io *fbdefio = info->fbdefio;
 	struct metronomefb_par *par = info->par;
 
-	/* walk the written page list and swizzle the data */
-	list_for_each_entry(cur, &fbdefio->pagelist, lru) {
-		cksum = metronomefb_dpy_update_page(par,
-					(cur->index << PAGE_SHIFT));
-		par->metromem_img_csum -= par->csum_table[cur->index];
-		par->csum_table[cur->index] = cksum;
-		par->metromem_img_csum += cksum;
+	/* force full screen update if dx is set or walk page list.
+	 *
+	 * normally, we need to update the dirty area pointed out by dx and
+	 * plus all dirty pages. in this driver any dirty area pointed out
+	 * by dx results in a full screen update. and since the entire screen
+	 * is updated in that case we can skip walking the page list.
+	 */
+	if (fbdefio->dx != -1) {
+		/* update the entire screen */
+		metronomefb_dpy_update(par);
+	} else {
+		/* walk the written page list and swizzle the data */
+		list_for_each_entry(cur, &fbdefio->pagelist, lru) {
+			cksum = metronomefb_dpy_update_page(par,
+						(cur->index << PAGE_SHIFT));
+			par->metromem_img_csum -= par->csum_table[cur->index];
+			par->csum_table[cur->index] = cksum;
+			par->metromem_img_csum += cksum;
+		}
 	}
 
 	metronome_display_cmd(par);
 }
 
-static void metronomefb_fillrect(struct fb_info *info,
-				   const struct fb_fillrect *rect)
-{
-	struct metronomefb_par *par = info->par;
-
-	sys_fillrect(info, rect);
-	metronomefb_dpy_update(par);
-}
-
-static void metronomefb_copyarea(struct fb_info *info,
-				   const struct fb_copyarea *area)
-{
-	struct metronomefb_par *par = info->par;
-
-	sys_copyarea(info, area);
-	metronomefb_dpy_update(par);
-}
-
-static void metronomefb_imageblit(struct fb_info *info,
-				const struct fb_image *image)
-{
-	struct metronomefb_par *par = info->par;
-
-	sys_imageblit(info, image);
-	metronomefb_dpy_update(par);
-}
-
-/*
- * this is the slow path from userspace. they can seek and write to
- * the fb. it is based on fb_sys_write
- */
-static ssize_t metronomefb_write(struct fb_info *info, const char __user *buf,
-				size_t count, loff_t *ppos)
-{
-	struct metronomefb_par *par = info->par;
-	unsigned long p = *ppos;
-	void *dst;
-	int err = 0;
-	unsigned long total_size;
-
-	if (info->state != FBINFO_STATE_RUNNING)
-		return -EPERM;
-
-	total_size = info->fix.smem_len;
-
-	if (p > total_size)
-		return -EFBIG;
-
-	if (count > total_size) {
-		err = -EFBIG;
-		count = total_size;
-	}
-
-	if (count + p > total_size) {
-		if (!err)
-			err = -ENOSPC;
-
-		count = total_size - p;
-	}
-
-	dst = (void __force *)(info->screen_base + p);
-
-	if (copy_from_user(dst, buf, count))
-		err = -EFAULT;
-
-	if  (!err)
-		*ppos += count;
-
-	metronomefb_dpy_update(par);
-
-	return (err) ? err : count;
-}
-
 static struct fb_ops metronomefb_ops = {
 	.owner		= THIS_MODULE,
-	.fb_write	= metronomefb_write,
-	.fb_fillrect	= metronomefb_fillrect,
-	.fb_copyarea	= metronomefb_copyarea,
-	.fb_imageblit	= metronomefb_imageblit,
+	.fb_read        = fb_deferred_io_read,
+	.fb_write	= fb_deferred_io_write,
+	.fb_fillrect	= fb_deferred_io_fillrect,
+	.fb_copyarea	= fb_deferred_io_copyarea,
+	.fb_imageblit	= fb_deferred_io_imageblit,
 };
 
 static struct fb_deferred_io metronomefb_defio = {