Commit 75a5f89f authored by Mark Brown's avatar Mark Brown
Browse files

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: default avatarMark Brown <broonie@opensource.wolfsonmicro.com>
Reviewed-by: default avatarDimitris Papastamos <dp@opensource.wolfsonmicro.com>
parent cfdeb8c3

drivers/base/regmap/regcache.c

+47 −17
Original line number Diff line number Diff line
@@ -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)

			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 && val == map->reg_defaults[ret].def) {

			ret = regcache_sync_block_raw_flush(map, &data,

							    base, regtmp);

			if (ret != 0)

				return ret;

		dev_dbg(map->dev, "Synced register %#x, value %#x\n",

			regtmp, val);

			continue;

		}



	return 0;

		if (!data) {

			data = regcache_get_val_addr(map, block, i);

			base = regtmp;

		}

	}



	return regcache_sync_block_raw_flush(map, &data, base, regtmp);

}



int regcache_sync_block(struct regmap *map, void *block,

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