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: linux-snps-arc@lists.infradead.org ---
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
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_ */