diff options
| author | Sander Vanheule <sander@svanheule.net> | 2025-10-29 09:12:47 +0100 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2025-10-29 12:54:04 +0000 |
| commit | 9c7f7262bc1affb9b9acd2ec2fb1f6314d5d474c (patch) | |
| tree | 966568ad1978d9e4945af06b6d372aa90c30c508 /include/linux/regmap.h | |
| parent | dcb6fa37fd7bc9c3d2b066329b0d27dedf8becaa (diff) | |
regmap: add flat cache with sparse validity
The flat regcache will always assume the data in the cache is valid.
Since the cache is preferred over hardware access, this may shadow the
actual state of the device.
Add a new containing cache structure with the flat data table and a
bitmap indicating cache validity. REGCACHE_FLAT will still behave as
before, as the validity is ignored.
Define new cache type REGCACHE_FLAT_S: a flat cache with sparse
validity. The sparse validity is used to determine if a hardware access
should occur to initialize the cache on the fly, vs. at regmap init for
REGCACHE_FLAT. Contrary to REGCACHE_FLAT, this allows us to implement
regcache_ops.drop.
Signed-off-by: Sander Vanheule <sander@svanheule.net>
Link: https://patch.msgid.link/20251029081248.52607-2-sander@svanheule.net
Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'include/linux/regmap.h')
| -rw-r--r-- | include/linux/regmap.h | 17 |
1 files changed, 11 insertions, 6 deletions
diff --git a/include/linux/regmap.h b/include/linux/regmap.h index 4e1ac1fbcec4..17bed25dc4e3 100644 --- a/include/linux/regmap.h +++ b/include/linux/regmap.h @@ -55,18 +55,23 @@ struct sdw_slave; #define REGMAP_DOWNSHIFT(s) (s) /* - * The supported cache types, the default is no cache. Any new caches - * should usually use the maple tree cache unless they specifically - * require that there are never any allocations at runtime and can't - * provide defaults in which case they should use the flat cache. The - * rbtree cache *may* have some performance advantage for very low end - * systems that make heavy use of cache syncs but is mainly legacy. + * The supported cache types, the default is no cache. Any new caches should + * usually use the maple tree cache unless they specifically require that there + * are never any allocations at runtime in which case they should use the sparse + * flat cache. The rbtree cache *may* have some performance advantage for very + * low end systems that make heavy use of cache syncs but is mainly legacy. + * These caches are sparse and entries will be initialized from hardware if no + * default has been provided. + * The non-sparse flat cache is provided for compatibility with existing users + * and will zero-initialize cache entries for which no defaults are provided. + * New users should use the sparse flat cache. */ enum regcache_type { REGCACHE_NONE, REGCACHE_RBTREE, REGCACHE_FLAT, REGCACHE_MAPLE, + REGCACHE_FLAT_S, }; /** |