From 99e8dd39f34333d745e6c220be5d166e85214e6c Mon Sep 17 00:00:00 2001 From: Charles Keepax Date: Thu, 1 Jun 2023 11:10:36 +0100 Subject: 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 Link: https://lore.kernel.org/r/20230601101036.1499612-2-ckeepax@opensource.cirrus.com Signed-off-by: Mark Brown --- drivers/base/regmap/regmap.c | 26 ++++++++++++++++---------- 1 file changed, 16 insertions(+), 10 deletions(-) (limited to 'drivers/base') 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; } -- cgit v1.2.3