fbdev: defio and Metronomefb

Implement support for the E-Ink Metronome controller.  It provides an mmapable
interface to the controller using defio support.  It was tested with a gumstix
pxa255 with Vizplex media using Xfbdev and various X clients such as xeyes,
xpdf, xloadimage.

This patch also fixes the following bug: Defio would cause a hang on write
access to the framebuffer as the page fault would be called ad-infinitum.  It
fixes fb_defio by setting the mapping to be used by page_mkclean.

Signed-off-by: Jaya Kumar <jayakumar.lkml@gmail.com>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 20 insertions, 2 deletions

diff --git a/drivers/video/fb_defio.c b/drivers/video/fb_defio.c
index 0f8cfb988c90..24843fdd5395 100644
--- a/drivers/video/fb_defio.c
+++ b/drivers/video/fb_defio.c
@@ -4,7 +4,7 @@
  *  Copyright (C) 2006 Jaya Kumar
  *
  * This file is subject to the terms and conditions of the GNU General Public
- * License.  See the file COPYING in the main directory of this archive
+ * License. See the file COPYING in the main directory of this archive
  * for more details.
  */
 
@@ -31,7 +31,7 @@ static int fb_deferred_io_fault(struct vm_area_struct *vma,
         unsigned long offset;
         struct page *page;
         struct fb_info *info = vma->vm_private_data;
-        /* info->screen_base is in System RAM */
+        /* info->screen_base is virtual memory */
         void *screen_base = (void __force *) info->screen_base;
 
         offset = vmf->pgoff << PAGE_SHIFT;
@@ -43,6 +43,15 @@ static int fb_deferred_io_fault(struct vm_area_struct *vma,
                 return VM_FAULT_SIGBUS;
 
         get_page(page);
+
+        if (vma->vm_file)
+                page->mapping = vma->vm_file->f_mapping;
+        else
+                printk(KERN_ERR "no mapping available\n");
+
+        BUG_ON(!page->mapping);
+        page->index = vmf->pgoff;
+
         vmf->page = page;
         return 0;
 }
@@ -138,11 +147,20 @@ EXPORT_SYMBOL_GPL(fb_deferred_io_init);
 
 void fb_deferred_io_cleanup(struct fb_info *info)
 {
+        void *screen_base = (void __force *) info->screen_base;
         struct fb_deferred_io *fbdefio = info->fbdefio;
+        struct page *page;
+        int i;
 
         BUG_ON(!fbdefio);
         cancel_delayed_work(&info->deferred_work);
         flush_scheduled_work();
+
+        /* clear out the mapping that we setup */
+        for (i = 0 ; i < info->fix.smem_len; i += PAGE_SIZE) {
+                page = vmalloc_to_page(screen_base + i);
+                page->mapping = NULL;
+        }
 }
 EXPORT_SYMBOL_GPL(fb_deferred_io_cleanup);