linux-kernel - [PATCH v2 1/2] regmap: fix writes to non incrementing registers

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Date:   Sat, 18 Jan 2020 20:56:24 +0000
From:   Ben Whitten <ben.whitten@...il.com>
To:     linux-kernel@...r.kernel.org
Cc:     afaerber@...e.de, Ben Whitten <ben.whitten@...il.com>,
        Mark Brown <broonie@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Han Nandor <nandor.han@...sala.com>
Subject: [PATCH v2 1/2] regmap: fix writes to non incrementing registers

When checking if a register block is writable we must ensure that the
block does not start with or contain a non incrementing register.

Fixes: 8b9f9d4dc511 ("regmap: verify if register is writeable before writing operations")
Signed-off-by: Ben Whitten <ben.whitten@...il.com>
---
 drivers/base/regmap/regmap.c | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index 19f57ccfbe1d..59f911e57719 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -1488,11 +1488,18 @@ static int _regmap_raw_write_impl(struct regmap *map, unsigned int reg,
 
 	WARN_ON(!map->bus);
 
-	/* Check for unwritable registers before we start */
-	for (i = 0; i < val_len / map->format.val_bytes; i++)
-		if (!regmap_writeable(map,
-				     reg + regmap_get_offset(map, i)))
-			return -EINVAL;
+	/* Check for unwritable or noinc registers in range
+	 * before we start
+	 */
+	if (!regmap_writeable_noinc(map, reg)) {
+		for (i = 0; i < val_len / map->format.val_bytes; i++) {
+			unsigned int element =
+				reg + regmap_get_offset(map, i);
+			if (!regmap_writeable(map, element) ||
+				regmap_writeable_noinc(map, element))
+				return -EINVAL;
+		}
+	}
 
 	if (!map->cache_bypass && map->format.parse_val) {
 		unsigned int ival;
-- 
2.17.1