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regmap: cache: Write consecutive registers in a single block write 

When syncing blocks of data using raw writes combine the writes into a
single block write, saving us bus overhead for setup, addressing and
teardown.

Currently the block write is done unconditionally as it is expected that
hardware which has a register format which can support raw writes will
support auto incrementing writes, this decision may need to be revised in
future.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Reviewed-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
This commit is contained in:
Mark Brown 2013-03-29 20:50:07 +00:00
parent cfdeb8c37e
commit 75a5f89f63
1 changed files with 47 additions and 17 deletions
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64
drivers/base/regmap/regcache.c
View File

@ -579,42 +579,72 @@ static int regcache_sync_block_single(struct regmap *map, void *block,
return 0;
}
static int regcache_sync_block_raw_flush(struct regmap *map, const void **data,
unsigned int base, unsigned int cur)
{
size_t val_bytes = map->format.val_bytes;
int ret, count;
if (*data == NULL)
return 0;
count = cur - base;
dev_dbg(map->dev, "Writing %d bytes for %d registers from 0x%x-0x%x\n",
count * val_bytes, count, base, cur - 1);
map->cache_bypass = 1;
ret = _regmap_raw_write(map, base, *data, count * val_bytes,
false);
map->cache_bypass = 0;
*data = NULL;
return ret;
}
int regcache_sync_block_raw(struct regmap *map, void *block,
unsigned int block_base, unsigned int start,
unsigned int end)
{
unsigned int i, regtmp, val;
const void *addr;
unsigned int i, val;
unsigned int regtmp = 0;
unsigned int base = 0;
const void *data = NULL;
int ret;
for (i = start; i < end; i++) {
regtmp = block_base + (i * map->reg_stride);
if (!regcache_reg_present(map, regtmp))
if (!regcache_reg_present(map, regtmp)) {
ret = regcache_sync_block_raw_flush(map, &data,
base, regtmp);
if (ret != 0)
return ret;
continue;
}
val = regcache_get_val(map, block, i);
/* Is this the hardware default? If so skip. */
ret = regcache_lookup_reg(map, regtmp);
if (ret >= 0 && val == map->reg_defaults[ret].def)
if (ret >= 0 && val == map->reg_defaults[ret].def) {
ret = regcache_sync_block_raw_flush(map, &data,
base, regtmp);
if (ret != 0)
return ret;
continue;
}
map->cache_bypass = 1;
addr = regcache_get_val_addr(map, block, i);
ret = _regmap_raw_write(map, regtmp, addr,
map->format.val_bytes,
false);
map->cache_bypass = 0;
if (ret != 0)
return ret;
dev_dbg(map->dev, "Synced register %#x, value %#x\n",
regtmp, val);
if (!data) {
data = regcache_get_val_addr(map, block, i);
base = regtmp;
}
}
return 0;
return regcache_sync_block_raw_flush(map, &data, base, regtmp);
}
int regcache_sync_block(struct regmap *map, void *block,