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Commit 086567f1 authored by Pavel Machek's avatar Pavel Machek Committed by Boris Brezillon
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mtd: nand: Optimize checking of erased buffers 



If we see ~0UL in flash, there's no need for hweight, and no need to
check number of bitflips. So this should be net win.

Signed-off-by: default avatarPavel Machek <pavel@denx.de>
Signed-off-by: default avatarBoris Brezillon <boris.brezillon@free-electrons.com>
parent 838ff7b3

drivers/mtd/nand/nand_base.c

+4 −1
Original line number Diff line number Diff line
@@ -1421,7 +1421,10 @@ static int nand_check_erased_buf(void *buf, int len, int bitflips_threshold) 


	for (; len >= sizeof(long);

	     len -= sizeof(long), bitmap += sizeof(long)) {

		weight = hweight_long(*((unsigned long *)bitmap));

		unsigned long d = *((unsigned long *)bitmap);

		if (d == ~0UL)

			continue;

		weight = hweight_long(d);

		bitflips += BITS_PER_LONG - weight;

		if (unlikely(bitflips > bitflips_threshold))

			return -EBADMSG;