Re: [microblaze-uclinux] JFFS2 and MTD

[Robert Swindells <rjs@fdy2.demon.co.uk>]

John Williams wrote:
>Robert Swindells wrote:
>> John Williams wrote:

>> If it were me, I would put the entries in ascending order and remove
>> the final flash entry.
>> 
>> static struct mtd_partition mbvanilla_8mb[] = {
>> 	{ name: "Bootloader", offset: 0x00000000, size:   0x00020000 },
>> 	{ name: "Bootargs",   offset: 0x00020000, size:   0x00020000 },
>> 	{ name: "MAC",        offset: 0x00040000, size:   0x00020000 },
>> 	{ name: "Spare",      offset: 0x00060000, size:   0x00020000 },
>> 	{ name: "Config",     offset: 0x00080000, size:   0x00080000 },
>> 	{ name: "Image",      offset: 0x00100000, size:   0x00200000 },
>> 	{ name: "JFFS2",      offset: 0x00300000, size:   0x00500000 }
>> };

>OK thanks I'll check it out.  I've copied this map config from the 
>snapgear board configs - they use uclinux and mtd extensively.

The order probably doesn't matter since your listing of /proc/mtd
looked fine for the "Spare" partition, I'm not sure that the "Flash"
one would work across a mixture of block sizes though.

>> How did you initialize the JFFS2 partition ?

>I haven't - I saw that the output of mkfs.jffs2 when run on an empty 
>directory was itself empty, so just figured I could mount straight on 
>top of an empty mtdblock device.

Had you erased the area ?

I don't think I have ever tried using a totally empty filesystem. I
always created a small "seed" filesystem using mkfs.jffs2 containing
a few files.

>Also another thing that's probably related that I'm unsure about, when 
>my board boots the JFFS2 driver is trying very hard to do something - I 
>get a bunch of messages like this:
>
>jffs2_scan_eraseblock(): Magic bitmask 0x1985 not found at 0x000ad024: 
>0x3630 id
>Further such events for this erase block will not be printed 
>
>JFFS2: Erase block at 0x000ad000 is not formatted. It will be erased 
>
>jffs2_scan_eraseblock(): Magic bitmask 0x1985 not found at 0x000ae000: 
>0x2f62 id
>jffs2_scan_eraseblock

The offsets look as if JFFS2 is using the wrong blocksize.

>Is JFFS2 trying to mount some kind of default fdile system?  This is all 
>happening before the shell starts, and before I can do any explicit 
>mount -t jffs2 commands.

It isn't trying to mount anything at this stage, it will just format
up any blocks that are not marked as being already used. This works
best if the unused blocks are cleared.

Robert Swindells

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