diff mbox

[4/5,v5] arc: Add our own implementation of fb_pgprotect()

Message ID 1459164999-11850-5-git-send-email-abrodkin@synopsys.com
State New
Headers show

Commit Message

Alexey Brodkin March 28, 2016, 11:36 a.m. UTC 
During mmaping of frame-buffer pages to user-space
fb_protect() is called to set proper page settings.

In case of ARC we need to mark pages that are mmaped to
user as uncached because of 2 reasons:
 * Huge amount of data if passing through data cache will
   thrash cache a lot making cache almost useless for other
   less traffic hungry processes.
 * Data written by user in FB will be immediately available for
   hardware (such as PGU etc) without requirements to flush data
   cache regularly.

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: linux-snps-arc@lists.infradead.org
---

No changes v4 -> v5.

Changes v3 -> v4:
 * This change was introduced only in v4.

 arch/arc/include/asm/fb.h | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)
 create mode 100644 arch/arc/include/asm/fb.h

Comments

Alexey Brodkin April 5, 2016, 6:35 p.m. UTC | #1 
Hi Vineet,

> From: Alexey Brodkin [abrodkin@synopsys.com]
> Sent: Monday, March 28, 2016 2:36 PM
> To: dri-devel@lists.freedesktop.org
> Cc: linux-kernel@vger.kernel.org; Alexey Brodkin; Vineet Gupta; linux-snps-arc@lists.infradead.org
> Subject: [PATCH 4/5 v5] arc: Add our own implementation of fb_pgprotect()
> 
> During mmaping of frame-buffer pages to user-space
> fb_protect() is called to set proper page settings.
> 
> In case of ARC we need to mark pages that are mmaped to
> user as uncached because of 2 reasons:
>  * Huge amount of data if passing through data cache will
>    thrash cache a lot making cache almost useless for other
>     less traffic hungry processes.
>  * Data written by user in FB will be immediately available for
>    hardware (such as PGU etc) without requirements to flush data
>    cache regularly.
> 
> Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
> Cc: Vineet Gupta <vgupta@synopsys.com>
> Cc: linux-snps-arc@lists.infradead.org

Could you please pick up this patch in your tree so in DRM-related series won't be external dependencies any longer?

-Alexey
diff mbox

Patch

diff --git a/arch/arc/include/asm/fb.h b/arch/arc/include/asm/fb.h
new file mode 100644
index 0000000..bd3f68c
--- /dev/null
+++ b/arch/arc/include/asm/fb.h
@@ -0,0 +1,19 @@ 
+#ifndef _ASM_FB_H_
+#define _ASM_FB_H_
+
+#include <linux/fb.h>
+#include <linux/fs.h>
+#include <asm/page.h>
+
+static inline void fb_pgprotect(struct file *file, struct vm_area_struct *vma,
+				unsigned long off)
+{
+	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+}
+
+static inline int fb_is_primary_device(struct fb_info *info)
+{
+	return 0;
+}
+
+#endif /* _ASM_FB_H_ */