mkfs.jffs2 --cleanmarker=?

I'm developing a proprietary nand flash driver based on the drivers/mtd/nand/nand_base.c code. I can successfully read and write the nand device in char mode, but when I write a jffs2 file system on it I get these CLEANMARKER errors:
CLEANMARKER node found at 0x00000000 has totlen 0xc != normal 0x0 CLEANMARKER node found at 0x00004000 has totlen 0xc != normal 0x0 CLEANMARKER node found at 0x00008000 has totlen 0xc != normal 0x0 CLEANMARKER node found at 0x0000c000 has totlen 0xc != normal 0x0
...
for every single block.

The Samsung nand chip we use is has 512 byte pages, 16 byte OOB area and 16 Kbyte erase blocks:
dev: size erasesize name
mtd0: 00800000 00004000 "Boot Image"
mtd1: 01800000 00004000 "Root FS (JFFS2)"

I can successfully boot from the mtd0 partiion. But when I create my jffs2 image I use
mkfs.jffs2 -s 0x200 -e 0x4000 -o jffs2.image

and copy it,
cp jffs2.image /dev/mtd1

but when I mount the partion using
mount -t jffs2 /dev/mtdblock1 /mnt/nf

I get the above errors. The fs seems to function okay, but this slew of errors seems ominous. (Same results if I mount the partition as my root fs).

What is the --cleanmarker option? Is it related to the oob size? I tried -c 16 and the error changed to "totlen 0x10 != normal 0x0". Perhaps -c 0 would mask these errors, but before I do that I wanted to see what exactly the cleanmarker meant.

I'm using jffs2 sources from Linux 2.6.11. I see you latest distribution is more recent. Is it worth it for me to port your distribution to my linux version, or am I doing something fundamentally ignorant?

Thanks in advance.
Phil

What is cleanmarker and what it is used for ?

Cleanmarker is a special JFFS2 node which is written to the beginning of a block just after the block has been erased. On NOR flashes it is a special small JFFS2 node at the beginning of the block. On NAND flashes it is placed to the spare area of the first page.

The main reason why cleanmarkers are used is the need to be sure that the block erase operation was correctly completed. All 0xFF bytes in the block are not necessarily mean the block is ready to be utilized. For example, if an unclean reboot happened just at the end of the block erase cycle, the block might have unstable bits, which are read as "1" one time and might be read as "0" next time.

When preparing a flash partition for JFFS2, it is recommended to put cleanmarkers to the erased blocks. This might be done my means of "-j" option of the "flash_eraseall" MTD utility. Otherwise, JFFS2 will re- erase the blocks which contain all 0xFF and have no cleanmarker. This is an unneeded wasting of time.

Munira Ahmed
Senior Embedded Specialist

Radixs Pte Ltd
Email:[email protected]


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What for ? The nand_base.c code can deal with your chip and just needs a small and simple board support driver.

tglx