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author | Charles Keepax <ckeepax@opensource.cirrus.com> | 2023-06-01 11:10:36 +0100 |
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committer | Mark Brown <broonie@kernel.org> | 2023-06-01 12:32:53 +0100 |
commit | 99e8dd39f34333d745e6c220be5d166e85214e6c (patch) | |
tree | d42eb7bac014213e3a19312b5d1b7b715093786c /drivers/base | |
parent | 02534c8e967b51940ae7c0cd99befe216f1c2c8d (diff) | |
download | linux-99e8dd39f34333d745e6c220be5d166e85214e6c.tar.gz linux-99e8dd39f34333d745e6c220be5d166e85214e6c.tar.bz2 linux-99e8dd39f34333d745e6c220be5d166e85214e6c.zip |
regmap: Add missing cache_only checks
The current behaviour around cache_only is slightly inconsistent,
most paths will only check cache_only if cache_bypass is false,
and will return -EBUSY if a read attempts to go to the hardware
whilst cache_only is true. However, a couple of paths will not check
cache_only at all. The most notable of these being regmap_raw_read
which will check cache_only in the case it processes the transaction
one register at a time, but not in the case it handles them as a
block. In the typical case a device has been put into cache_only
whilst powered down this can cause physical reads to happen whilst the
device is unavailable.
Add a check in regmap_raw_read and move the check in regmap_noinc_read,
adding a check for cache_bypass, such that all paths are covered and
consistent.
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20230601101036.1499612-2-ckeepax@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/base')
-rw-r--r-- | drivers/base/regmap/regmap.c | 26 |
1 files changed, 16 insertions, 10 deletions
diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c index db7851f0e3b8..f337c7930954 100644 --- a/drivers/base/regmap/regmap.c +++ b/drivers/base/regmap/regmap.c @@ -2981,6 +2981,11 @@ int regmap_raw_read(struct regmap *map, unsigned int reg, void *val, size_t chunk_count, chunk_bytes; size_t chunk_regs = val_count; + if (!map->cache_bypass && map->cache_only) { + ret = -EBUSY; + goto out; + } + if (!map->read) { ret = -ENOTSUPP; goto out; @@ -3076,18 +3081,19 @@ int regmap_noinc_read(struct regmap *map, unsigned int reg, goto out_unlock; } + /* + * We have not defined the FIFO semantics for cache, as the + * cache is just one value deep. Should we return the last + * written value? Just avoid this by always reading the FIFO + * even when using cache. Cache only will not work. + */ + if (!map->cache_bypass && map->cache_only) { + ret = -EBUSY; + goto out_unlock; + } + /* Use the accelerated operation if we can */ if (map->bus->reg_noinc_read) { - /* - * We have not defined the FIFO semantics for cache, as the - * cache is just one value deep. Should we return the last - * written value? Just avoid this by always reading the FIFO - * even when using cache. Cache only will not work. - */ - if (map->cache_only) { - ret = -EBUSY; - goto out_unlock; - } ret = regmap_noinc_readwrite(map, reg, val, val_len, false); goto out_unlock; } |