From e745d064b441dbf48eac4bc2c494263d54262dec Mon Sep 17 00:00:00 2001
From: Hans de Goede <hdegoede@redhat.com>
Date: Mon, 24 Nov 2014 13:47:13 +0100
Subject: [PATCH] edid: Add an edid_check_checksum() helper function
Add a helper function to check the checksum of an EDID data block.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Anatolij Gustschin <agust@denx.de>
---
common/edid.c | 12 ++++++++++++
include/edid.h | 9 +++++++++
2 files changed, 21 insertions(+)
diff --git a/common/edid.c b/common/edid.c
index e66108f24a..df797fcdd5 100644
--- a/common/edid.c
+++ b/common/edid.c
@@ -12,6 +12,7 @@
#include <common.h>
#include <edid.h>
+#include <errno.h>
#include <linux/ctype.h>
#include <linux/string.h>
@@ -29,6 +30,17 @@ int edid_check_info(struct edid1_info *edid_info)
return 0;
}
+int edid_check_checksum(u8 *edid_block)
+{
+ u8 checksum = 0;
+ int i;
+
+ for (i = 0; i < 128; i++)
+ checksum += edid_block[i];
+
+ return (checksum == 0) ? 0 : -EINVAL;
+}
+
int edid_get_ranges(struct edid1_info *edid, unsigned int *hmin,
unsigned int *hmax, unsigned int *vmin,
unsigned int *vmax)
diff --git a/include/edid.h b/include/edid.h
index d3cc5232de..a69f43a206 100644
--- a/include/edid.h
+++ b/include/edid.h
@@ -245,6 +245,15 @@ void edid_print_info(struct edid1_info *edid_info);
*/
int edid_check_info(struct edid1_info *info);
+/**
+ * Check checksum of a 128 bytes EDID data block
+ *
+ * @param edid_block EDID block data
+ *
+ * @return 0 on success, or a negative errno on error
+ */
+int edid_check_checksum(u8 *edid_block);
+
/**
* Get the horizontal and vertical rate ranges of the monitor.
*
--
2.39.5