This patch enable writing nand flash via NFC SRAM. It will minimize the CPU
overhead. The SRAM write only support ECC_NONE and ECC_HW with PMECC.
To enable this NFC write by SRAM feature, you can add a string in dts under
NFC driver node.
This driver has been tested on SAMA5D3X-EK with JFFS2, YAFFS2, UBIFS and
mtd-utils.
Here is part of mtd_speedtest (writing test) result, compare with non-NFC
writing, it reduces %65 cpu load with loss %12 speed.
- commands use to test:
# insmod /mnt/mtd_speedtest.ko dev=2 &
# top -n 30 -d 1 | grep speedtest
- test result:
=================================================
mtd_speedtest: MTD device: 2
mtd_speedtest: MTD device size 41943040, eraseblock size 131072, page size 2048, count of eraseblocks 320, pages per eraseblock 64, OOB size 64
mtd_speedtest: testing eraseblock write speed
509 495 root D 1164 0% 7% insmod /mnt/mtd_speedtest.ko dev=2
509 495 root D 1164 0% 8% insmod /mnt/mtd_speedtest.ko dev=2
509 495 root R 1164 0% 5% insmod /mnt/mtd_speedtest.ko dev=2
mtd_speedtest: eraseblock write speed is 5194 KiB/s
mtd_speedtest: testing page write speed
509 495 root D 1164 0% 32% insmod /mnt/mtd_speedtest.ko dev=2
509 495 root D 1164 0% 27% insmod /mnt/mtd_speedtest.ko dev=2
509 495 root D 1164 0% 25% insmod /mnt/mtd_speedtest.ko dev=2
509 495 root D 1164 0% 30% insmod /mnt/mtd_speedtest.ko dev=2
mtd_speedtest: page write speed is 5024 KiB/s
Signed-off-by: Josh Wu <josh.wu@atmel.com>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
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