UM0851 Datasheet, PDF (135/245 Pages) STMicroelectronics – SPEAr is a family of highly customizable ARM-based embedded

UM0851
Non-volatile memory device drivers
5.1.5
5.1.6
NAND Flash file system image creation
YAFFS2 image creation
To create the YAFFS2 file system image for 512 byte page NAND Flash, use the command:
# mkyaffsimage <layout no> <dir name> <image name>
#
To create the YAFFS2 file system image for 2048 byte page NAND Flash, use the
command:
# mkyaffs2image <layout no> <dir name > <image name >
#
These commands create the image, which contains OOB. Hence for a 512 byte page NAND
Flash, the image size must be divisible by 528 (512 byte data + 16 byte OOB).
JFFS2 image creation
To create the JFFS2 file system image for a 512 byte page NAND Flash, use the command:
# mkfs.jffs2 -n -p -l -s 0x200 -e 0x4000 -r <dir name > -o <image name >
#
To create the JFFS2 file system image for a 2048 byte page NAND Flash, use the
command:
# mkfs.jffs2 -n -p -l -s 0x800 -e 0x20000 -r <dir name > -o <image name >
#
-n: don't add a cleanmarker to every eraseblock
-p: add pad bytes to the end of the final erase block
-l: create a little-endian file-system
-s: page size
-e: erase block size
These commands create the image, which does not contain OOB. Hence for 512 byte page
NAND Flash, the image size must be divisible by 512 (512 byte data).
NAND device driver performance
The performance measurement has been performed using:
● Hardware: ARM926EJS (333 MHz), STMicroelectronics NAND 512W3A2CZA6 Flash.
● Test file system on the NAND Flash: YAFFS2 and JFFS2 (for /dev/mtdblock7)
● Kernel: Linux-2.6.27.
● Driver: DMA was disabled
Results for YAFFS2
Mount YAFFS2 fs and write/read to a file. The sequence is as follows:
Doc ID 16604 Rev 2
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