Since in SAMA5D4 chip, the PMECC can correct bit flips in erased page.
So we add a DT property to indicate this hardware character.
If the PMECC support correct bitflip erased page (all data are 0xff).
Then we can use the PMECC correct the page and skip the erased page
check.
Signed-off-by: Josh Wu <josh.wu@atmel.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
If there is no PMECC lookup table stored in ROM, or lookup table offset is
not specified, PMECC driver should build it in DDR by itself.
That make the PMECC driver work for some board which doesn't have PMECC
lookup table in ROM.
The PMECC use the BCH algorithm, so based on the build_gf_tables()
function in lib/bch.c, we can build the Galois Field lookup table.
For more information can refer to section 5.4 of PMECC controller
application note:
http://www.atmel.com/images/doc11127.pdf
Signed-off-by: Josh Wu <josh.wu@atmel.com>
Cc: devicetree@vger.kernel.org
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Retrieve the NFC clock to make sure it is enabled. Make that optional to ensure
compatibility with previous device trees but document it as mandatory so newer
device trees will include it.
Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Josh Wu <josh.wu@atmel.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
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>
This patch will set the nand dma support in dts. Since we will not use
cpu_is_xxx() in nand driver. We needn't include the mach/cpu.h any more.
Signed-off-by: Josh Wu <josh.wu@atmel.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Add comments to NAND "gpios" property to make it clearer.
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Use a local copy of board informatin and fill with DT data.
Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
Wu, Josh