From 6054d4d56307839bffabb687767c24d5ff62563b Mon Sep 17 00:00:00 2001 From: Josh Wu Date: Mon, 5 Aug 2013 19:14:37 +0800 Subject: mtd: atmel_nand: enable Nand Flash Controller (NFC) write via sram 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 Acked-by: Jean-Christophe PLAGNIOL-VILLARD Signed-off-by: Artem Bityutskiy Signed-off-by: David Woodhouse --- Documentation/devicetree/bindings/mtd/atmel-nand.txt | 2 ++ 1 file changed, 2 insertions(+) (limited to 'Documentation/devicetree/bindings/mtd') diff --git a/Documentation/devicetree/bindings/mtd/atmel-nand.txt b/Documentation/devicetree/bindings/mtd/atmel-nand.txt index 5d8b7d5c914d..c4728839d0c1 100644 --- a/Documentation/devicetree/bindings/mtd/atmel-nand.txt +++ b/Documentation/devicetree/bindings/mtd/atmel-nand.txt @@ -36,6 +36,8 @@ Optional properties: - reg : should specify the address and size used for NFC command registers, NFC registers and NFC Sram. NFC Sram address and size can be absent if don't want to use it. + - Optional properties: + - atmel,write-by-sram: boolean to enable NFC write by sram. Examples: nand0: nand@40000000,0 { -- cgit v1.2.3