[PATCH 3/4] misc: fuse: Fix FSB redundancy fuse word check and clear res

[Peng Fan (OSS)]

From: Ye Li <ye.li at nxp.com>

There is a bug when checking fuse word with redundancy fuse in FSB
table. The redundancy fuses are combined into 4 words, so we can't
directly use word index to do the check, otherwise the high 4 words
will fail to match.

And When calling ELE API, res parameter will pass to ELE API to get ELE
response value for failure. So most of usage does not initialize
this variable and print it after calling ELE API.
However, when ELE API returns failure, we can't ensure this res is
always set because there may be other failure like MU failure.

Reviewed-by: Peng Fan <peng.fan at nxp.com>
Signed-off-by: Ye Li <ye.li at nxp.com>
Signed-off-by: Peng Fan <peng.fan at nxp.com>
---
 drivers/misc/imx_ele/fuse.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/misc/imx_ele/fuse.c b/drivers/misc/imx_ele/fuse.c
index d12539c8aac..47880d8aeea 100644
--- a/drivers/misc/imx_ele/fuse.c
+++ b/drivers/misc/imx_ele/fuse.c
@@ -138,8 +138,7 @@ static s32 map_fsb_fuse_index(u32 bank, u32 word, bool *redundancy)
 	/* map the fuse from ocotp fuse map to FSB*/
 	for (i = 0; i < size; i++) {
 		if (fsb_mapping_table[i].fuse_bank != -1 &&
-		    fsb_mapping_table[i].fuse_bank == bank &&
-		    fsb_mapping_table[i].fuse_words > word) {
+		    fsb_mapping_table[i].fuse_bank == bank) {
 			break;
 		}
 
@@ -150,8 +149,13 @@ static s32 map_fsb_fuse_index(u32 bank, u32 word, bool *redundancy)
 		return -1; /* Failed to find */
 
 	if (fsb_mapping_table[i].redundancy) {
+		if ((fsb_mapping_table[i].fuse_words << 1) <= word)
+			return -2; /* Not valid word */
+
 		*redundancy = true;
 		return (word >> 1) + word_pos;
+	} else if (fsb_mapping_table[i].fuse_words <= word) {
+		return -2; /* Not valid word */
 	}
 
 	*redundancy = false;
@@ -204,7 +208,7 @@ int fuse_sense(u32 bank, u32 word, u32 *val)
 	word_index = map_ele_fuse_index(bank, word);
 	if (word_index >= 0) {
 		u32 data[4];
-		u32 res, size = 4;
+		u32 res = 0, size = 4;
 		int ret;
 
 		/* Only UID return 4 words */
@@ -257,7 +261,7 @@ int fuse_sense(u32 bank, u32 word, u32 *val)
 	word_index = map_ele_fuse_index(bank, word);
 	if (word_index >= 0) {
 		u32 data;
-		u32 res, size = 1;
+		u32 res = 0, size = 1;
 		int ret;
 
 		ret = ele_read_common_fuse(word_index, &data, size, &res);
@@ -282,7 +286,7 @@ int fuse_read(u32 bank, u32 word, u32 *val)
 
 int fuse_prog(u32 bank, u32 word, u32 val)
 {
-	u32 res;
+	u32 res = 0;
 	int ret;
 	bool lock = false;
 
-- 
2.35.3