[PATCH 1/3] drm/edid: new drm_edid_block_checksum helper function V2

[Stefan Brüns]

The function will also be used by a later patch, so factor it out.

V2: make raw_edid const, define/declare before first use

Signed-off-by: Stefan Brüns <stefan.bruens at rwth-aachen.de>
Reviewed-by: Jani Nikula <jani.nikula at intel.com>
---
 drivers/gpu/drm/drm_edid.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index a71ed93..f6c4a1d 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -1022,6 +1022,16 @@ static bool drm_edid_is_zero(const u8 *in_edid, int 
length)
        return true;
 }

+static u8 drm_edid_block_checksum(const u8 *raw_edid)
+{
+       int i;
+       u8 csum = 0;
+       for (i = 0; i < EDID_LENGTH; i++)
+               csum += raw_edid[i];
+
+       return csum;
+}
+
 /**
  * drm_edid_block_valid - Sanity check the EDID block (base or extension)
  * @raw_edid: pointer to raw EDID block
@@ -1036,7 +1046,6 @@ static bool drm_edid_is_zero(const u8 *in_edid, int 
length)
 bool drm_edid_block_valid(u8 *raw_edid, int block, bool print_bad_edid)
 {
        int i;
-       u8 csum = 0;
        struct edid *edid = (struct edid *)raw_edid;

        if (WARN_ON(!raw_edid))
@@ -1056,9 +1065,7 @@ bool drm_edid_block_valid(u8 *raw_edid, int block, bool 
print_bad_edid)
                }
        }

-       for (i = 0; i < EDID_LENGTH; i++)
-               csum += raw_edid[i];
-       if (csum) {
+       if (drm_edid_block_checksum(raw_edid)) {
                if (print_bad_edid) {
                        DRM_ERROR("EDID checksum is invalid, remainder is 
%d\n", csum);
                }
-- 
2.1.2