Messages in this thread Patch in this message | | | From | Charles Keepax <> | Subject | [PATCH 2/2] regmap: Add missing cache_only checks | Date | Thu, 1 Jun 2023 11:10:36 +0100 |
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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> --- drivers/base/regmap/regmap.c | 26 ++++++++++++++++---------- 1 file changed, 16 insertions(+), 10 deletions(-)
diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c index fa2d3fba6ac9d..627a767fa0470 100644 --- a/drivers/base/regmap/regmap.c +++ b/drivers/base/regmap/regmap.c @@ -2983,6 +2983,11 @@ 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; @@ -3078,18 +3083,19 @@ 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; } -- 2.30.2
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