[2/2] regmap: Add missing cache_only checks
Commit Message
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(-)
@@ -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;
}