video: fbdev: geode gxfb: use ioremap_wc() for framebuffer
authorLuis R. Rodriguez <mcgrof@suse.com>
Tue, 21 Apr 2015 20:16:38 +0000 (13:16 -0700)
committerTomi Valkeinen <tomi.valkeinen@ti.com>
Wed, 3 Jun 2015 09:41:53 +0000 (12:41 +0300)
commit9ccfc4aa6939b06c7d0cd1de04949be1eb2b0836
tree2491a6eb39cb010f4f16847bc1f41db9b86d1a54
parent1e43a20396ee34a6b0305fc155cb59af13a89435
video: fbdev: geode gxfb: use ioremap_wc() for framebuffer

The driver doesn't use mtrr_add() or arch_phys_wc_add() but
since we know the framebuffer is isolated already on an
ioremap() we can take advantage of write combining for
performance where possible.

In this case there are a few motivations for this:

a) Take advantage of PAT when available

b) Help with the goal of eventually using _PAGE_CACHE_UC over
   _PAGE_CACHE_UC_MINUS on x86 on ioremap_nocache() (see commit
   de33c442e titled "x86 PAT: fix performance drop for glx,
   use UC minus for ioremap(), ioremap_nocache() and
   pci_mmap_page_range()")

Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Jingoo Han <jg1.han@samsung.com>
Cc: Suresh Siddha <sbsiddha@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Juergen Gross <jgross@suse.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Antonino Daplas <adaplas@gmail.com>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: linux-geode@lists.infradead.org
Cc: linux-fbdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Reviewed-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
drivers/video/fbdev/geode/gxfb_core.c