linux-kernel - [PATCH 1/2] regmap: fix page selection for noinc reads

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Date:   Thu, 17 Sep 2020 18:19:19 +0300
From:   Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To:     Mark Brown <broonie@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>
Cc:     Crestez Dan Leonard <leonard.crestez@...el.com>,
        Stefan Popa <stefan.popa@...log.com>,
        Ben Whitten <ben.whitten@...il.com>,
        linux-kernel@...r.kernel.org
Subject: [PATCH 1/2] regmap: fix page selection for noinc reads

Non-incrementing reads can fail if register + length crosses page
border. However for non-incrementing reads we should not check for page
border crossing. Fix this by passing additional flag to _regmap_raw_read
and passing length to _regmap_select_page basing on the flag.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
Fixes: 74fe7b551f3385fa585d92616c85b3a575b2b2cb
---
 drivers/base/regmap/regmap.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index e93700af7e6e..01ecc00c8508 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -2450,7 +2450,7 @@ int regmap_raw_write_async(struct regmap *map, unsigned int reg,
 EXPORT_SYMBOL_GPL(regmap_raw_write_async);
 
 static int _regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
-			    unsigned int val_len)
+			    unsigned int val_len, bool noinc)
 {
 	struct regmap_range_node *range;
 	int ret;
@@ -2463,7 +2463,7 @@ static int _regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
 	range = _regmap_range_lookup(map, reg);
 	if (range) {
 		ret = _regmap_select_page(map, &reg, range,
-					  val_len / map->format.val_bytes);
+					  noinc ? 1 : val_len / map->format.val_bytes);
 		if (ret != 0)
 			return ret;
 	}
@@ -2501,7 +2501,7 @@ static int _regmap_bus_read(void *context, unsigned int reg,
 	if (!map->format.parse_val)
 		return -EINVAL;
 
-	ret = _regmap_raw_read(map, reg, work_val, map->format.val_bytes);
+	ret = _regmap_raw_read(map, reg, work_val, map->format.val_bytes, false);
 	if (ret == 0)
 		*val = map->format.parse_val(work_val);
 
@@ -2617,7 +2617,7 @@ int regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
 
 		/* Read bytes that fit into whole chunks */
 		for (i = 0; i < chunk_count; i++) {
-			ret = _regmap_raw_read(map, reg, val, chunk_bytes);
+			ret = _regmap_raw_read(map, reg, val, chunk_bytes, false);
 			if (ret != 0)
 				goto out;
 
@@ -2628,7 +2628,7 @@ int regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
 
 		/* Read remaining bytes */
 		if (val_len) {
-			ret = _regmap_raw_read(map, reg, val, val_len);
+			ret = _regmap_raw_read(map, reg, val, val_len, false);
 			if (ret != 0)
 				goto out;
 		}
@@ -2703,7 +2703,7 @@ int regmap_noinc_read(struct regmap *map, unsigned int reg,
 			read_len = map->max_raw_read;
 		else
 			read_len = val_len;
-		ret = _regmap_raw_read(map, reg, val, read_len);
+		ret = _regmap_raw_read(map, reg, val, read_len, true);
 		if (ret)
 			goto out_unlock;
 		val = ((u8 *)val) + read_len;
-- 
2.28.0