fbdev: add fb_read/fb_write functions for framebuffers in system RAM

The functions fb_read() and fb_write in fbmem.c assume that the framebuffer
is in IO memory.  However, we have 3 drivers (hecubafb, arcfb, and vfb)
where the framebuffer is allocated from system RAM (via vmalloc). Using
__raw_read/__raw_write (fb_readl/fb_writel) for these drivers is
illegal, especially in other platforms.

Create file read and write methods for these types of drivers.  These are
named fb_sys_read() and fb_sys_write().

Signed-off-by: Antonino Daplas <adaplas@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index 6d32726e8751..85d0e8707ee3 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -122,6 +122,11 @@ config FB_SYS_IMAGEBLIT
           blitting. This is used by drivers that don't provide their own
           (accelerated) version and the framebuffer is in system RAM.
 
+config FB_SYS_FOPS
+       tristate
+       depends on FB
+       default n
+
 config FB_DEFERRED_IO
         bool
         depends on FB