samsung: snow: bitfix: Use linux xor code

Linux already has some xor code that was optimized for RAID.  Include
it and use it for bitfix.  This appears to save 200-300 ms.

BUG=chrome-os-partner:15655
TEST=Timed before and after:
Before:
 [   28.344096] s3c_pm_check: Suspend memory scan took 4341511 usecs
 [   28.344096] s3c_pm_check: Resume memory scan took 1204971 usecs
 [   40.794096] s3c_pm_check: Suspend memory scan took 4372845 usecs
 [   40.794096] s3c_pm_check: Resume memory scan took 1205185 usecs
 [   53.689130] s3c_pm_check: Suspend memory scan took 4348640 usecs
 [   53.689130] s3c_pm_check: Resume memory scan took 1205305 usecs
After:
 [   34.604046] s3c_pm_check: Suspend memory scan took 4000453 usecs
 [   34.604046] s3c_pm_check: Resume memory scan took 1202673 usecs
 [   48.804021] s3c_pm_check: Suspend memory scan took 3991251 usecs
 [   48.804021] s3c_pm_check: Resume memory scan took 1202789 usecs
 [   62.234132] s3c_pm_check: Suspend memory scan took 4161455 usecs
 [   62.234132] s3c_pm_check: Resume memory scan took 1203661 usecs
 [   83.439127] s3c_pm_check: Suspend memory scan took 4002259 usecs
 [   83.439127] s3c_pm_check: Resume memory scan took 1205180 usecs

Change-Id: I17a6d6b8c072ac0fe04ae2fa8762374aafcae7ff
Signed-off-by: Doug Anderson <dianders@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/37691
Reviewed-by: Jon Kliegman <kliegs@chromium.org>
Reviewed-by: Sonny Rao <sonnyrao@chromium.org>

diff --git a/arch/arm/mach-exynos/Kconfig b/arch/arm/mach-exynos/Kconfig
index 0626539..7ea1034 100644 (file)
--- a/arch/arm/mach-exynos/Kconfig
+++ b/arch/arm/mach-exynos/Kconfig
@@ -461,6 +461,7 @@ endmenu
 config SNOW_BITFIX
        bool "Enable fixing of bit errors across suspend-to-RAM cycle"
        depends on SOC_EXYNOS5250 && SAMSUNG_PM_CHECK
+       select XOR_BLOCKS
        help
          Some Snow boards have an issue in read-only firmware that can cause
          bit errors across a suspend/resume cycle.  Enabling this option will

diff --git a/arch/arm/mach-exynos/bitfix-snow.c b/arch/arm/mach-exynos/bitfix-snow.c
index 14e54fe..9d2fbea 100644 (file)
--- a/arch/arm/mach-exynos/bitfix-snow.c
+++ b/arch/arm/mach-exynos/bitfix-snow.c
@@ -23,6 +23,7 @@
 #include <linux/moduleparam.h>
 #include <linux/of_fdt.h>
 #include <linux/pm.h>
+#include <linux/raid/xor.h>
 #include <linux/slab.h>
 
 #include <plat/pm.h>
@@ -283,18 +284,12 @@ static u32 bitfix_get_cu(phys_addr_t chunk)
  *
  * @dest: Place to xor into.
  * @src: Place to xor from.
- * @count: Number of _bytes_ to process.  Must be an even number of 32-bit
- *     elements.
+ * @count: Number of _bytes_ to process.
  */
 
-static void bitfix_xor32(u32 *dest, const u32 *src, size_t count)
+static void bitfix_xor32(void *dest, const void *src, size_t count)
 {
-       size_t i;
-
-       BUG_ON(count & 0x03);
-
-       for (i = 0; i < count / sizeof(u32); i++)
-               dest[i] ^= src[i];
+       xor_blocks(1, PAGE_SIZE, dest, (void **)&src);
 }
 
 /**