From eab5abdeb79f0f694c007c3a76a97902705c86f0 Mon Sep 17 00:00:00 2001
From: Mark Brown <broonie@kernel.org>
Date: Tue, 13 Jun 2023 21:07:16 +0100
Subject: [PATCH] regmap: Check for register readability before checking cache during read
Git-commit: eab5abdeb79f0f694c007c3a76a97902705c86f0
Patch-mainline: v6.5-rc1
References: jsc#PED-6045 jsc#PED-6036 jsc#PED-6104 jsc#PED-6114 jsc#PED-6067 jsc#PED-6123
Ensure that we don't return a spurious cache hit for unreadable registers
(eg, with the flat cache which doesn't understand sparseness) by checking
for readability before we do a cache lookup.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230613-b4-regmap-check-readability-before-cache-v1-1-b144c0b01ed9@kernel.org
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/base/regmap/regmap.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index 89a7f1c459c1..fad66b309ef9 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -2897,6 +2897,9 @@ static int _regmap_read(struct regmap *map, unsigned int reg,
int ret;
void *context = _regmap_map_get_context(map);
+ if (!regmap_readable(map, reg))
+ return -EIO;
+
if (!map->cache_bypass) {
ret = regcache_read(map, reg, val);
if (ret == 0)
@@ -2906,9 +2909,6 @@ static int _regmap_read(struct regmap *map, unsigned int reg,
if (map->cache_only)
return -EBUSY;
- if (!regmap_readable(map, reg))
- return -EIO;
-
ret = map->reg_read(context, reg, val);
if (ret == 0) {
if (regmap_should_log(map))
--
2.35.3