[coreboot-gerrit] New patch to review for coreboot: 46578c8 drivers/pc80/mc146818rtc: Fix checksum range test

[Kyösti Mälkki (kyosti.malkki@gmail.com)]

Kyösti Mälkki (kyosti.malkki at gmail.com) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/8383

-gerrit

commit 46578c8c5b63dd5485f69bdcc8076cfdf8c220e3
Author: Kyösti Mälkki <kyosti.malkki at gmail.com>
Date:   Sat Feb 7 09:13:02 2015 +0200

    drivers/pc80/mc146818rtc: Fix checksum range test
    
    When writing multiple bytes, only the last address was tested
    if it was in LB_CKS_RANGE.
    
    Change-Id: I34c0484e9758ef88e7005d0599f6055dc4f4fc59
    Signed-off-by: Kyösti Mälkki <kyosti.malkki at gmail.com>
---
 src/drivers/pc80/mc146818rtc.c | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/src/drivers/pc80/mc146818rtc.c b/src/drivers/pc80/mc146818rtc.c
index b18f22f..030980a 100644
--- a/src/drivers/pc80/mc146818rtc.c
+++ b/src/drivers/pc80/mc146818rtc.c
@@ -243,11 +243,19 @@ static enum cb_err set_cmos_value(unsigned long bit, unsigned long length,
 	unsigned long byte,byte_bit;
 	unsigned long i;
 	unsigned char uchar, mask;
-	unsigned int chksum_update_needed = 0;
+	unsigned int chksum_update_needed = 1;
 
 	ret = vret;
 	byte = bit / 8;		/* find the byte where the data starts */
 	byte_bit = bit % 8;	/* find the bit where the data starts */
+
+	if (length == 0)
+		return CB_SUCCESS;
+
+	/* Check if write stays outside of LB_CKS_RANGE. */
+	if ((byte + (length-1)/8 < LB_CKS_RANGE_START) || (byte > LB_CKS_RANGE_END))
+		chksum_update_needed = 0;
+
 	if (length <= 8) {	/* one byte or less */
 		mask = (1 << length) - 1;
 		mask <<= byte_bit;
@@ -256,23 +264,18 @@ static enum cb_err set_cmos_value(unsigned long bit, unsigned long length,
 		uchar &= ~mask;
 		uchar |= (ret[0] << byte_bit);
 		cmos_write(uchar, byte);
-		if (byte >= LB_CKS_RANGE_START && byte <= LB_CKS_RANGE_END)
-			chksum_update_needed = 1;
 	} else { /* more that one byte so transfer the whole bytes */
 		if (byte_bit || length % 8)
 			return CB_ERR_ARG;
 
 		for (i = 0; length; i++, length -= 8, byte++)
 			cmos_write(ret[i], byte);
-			if (byte >= LB_CKS_RANGE_START &&
-			    byte <= LB_CKS_RANGE_END)
-				chksum_update_needed = 1;
 	}
 
-	if (chksum_update_needed) {
+	if (chksum_update_needed)
 		cmos_set_checksum(LB_CKS_RANGE_START, LB_CKS_RANGE_END,
 				  LB_CKS_LOC);
-	}
+
 	return CB_SUCCESS;
 }