[PATCH 2/5] regmap: Tidy up regmap_raw_read chunking code

From: Charles Keepax
Date: Thu Feb 15 2018 - 12:53:01 EST


Raw reads may need to be split into small chunks if max_raw_read is
set. Tidy up the code implementing this, the new code is slightly
clearer, slightly shorter and slightly more efficient.

Signed-off-by: Charles Keepax <ckeepax@xxxxxxxxxxxxxxxxxxxxx>
---
drivers/base/regmap/regmap.c | 44 +++++++++++++++++++-------------------------
1 file changed, 19 insertions(+), 25 deletions(-)

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index f78ddaa9a1e8..93d4218c5569 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -2542,44 +2542,38 @@ int regmap_raw_read(struct regmap *map, unsigned int reg, void *val,

if (regmap_volatile_range(map, reg, val_count) || map->cache_bypass ||
map->cache_type == REGCACHE_NONE) {
- int chunk_stride = map->reg_stride;
- size_t chunk_size = val_bytes;
- size_t chunk_count = val_count;
+ size_t chunk_count, chunk_bytes;
+ size_t chunk_regs = val_count;

if (!map->bus->read) {
ret = -ENOTSUPP;
goto out;
}

- if (!map->use_single_read) {
- if (map->max_raw_read)
- chunk_size = map->max_raw_read;
- else
- chunk_size = val_len;
- if (chunk_size % val_bytes)
- chunk_size -= chunk_size % val_bytes;
- chunk_count = val_len / chunk_size;
- chunk_stride *= chunk_size / val_bytes;
- }
+ if (map->use_single_read)
+ chunk_regs = 1;
+ else if (map->max_raw_read && val_len > map->max_raw_read)
+ chunk_regs = map->max_raw_read / val_bytes;

- /* Read bytes that fit into a multiple of chunk_size */
+ chunk_count = val_count / chunk_regs;
+ chunk_bytes = chunk_regs * val_bytes;
+
+ /* Read bytes that fit into whole chunks */
for (i = 0; i < chunk_count; i++) {
- ret = _regmap_raw_read(map,
- reg + (i * chunk_stride),
- val + (i * chunk_size),
- chunk_size);
+ ret = _regmap_raw_read(map, reg, val, chunk_bytes);
if (ret != 0)
- return ret;
+ goto out;
+
+ reg += regmap_get_offset(map, chunk_regs);
+ val += chunk_bytes;
+ val_len -= chunk_bytes;
}

/* Read remaining bytes */
- if (chunk_size * i < val_len) {
- ret = _regmap_raw_read(map,
- reg + (i * chunk_stride),
- val + (i * chunk_size),
- val_len - i * chunk_size);
+ if (val_len) {
+ ret = _regmap_raw_read(map, reg, val, val_len);
if (ret != 0)
- return ret;
+ goto out;
}
} else {
/* Otherwise go word by word for the cache; should be low
--
2.11.0