A few questions (cramfs as root, flash permissions and JFFS2 on 2.2.18)

A few questions (cramfs as root, flash permissions and JFFS2 on 2.2.18)

[Chris AtLee]

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Hi there,

I'm trying to get MTD (from CVS as of a few days ago) up and running on
my embedded device which is using an Intel Strataflash 4 MB flash chip
(mapped into physical memory) and running linux 2.2.18.

I've created my own mapping which defines four partitions: bootloader,
kernel, applications and data.  At this point I am able to boot up the
unit from mtdblock2 with a romfs image on it and then mount cramfs
images from mtdblock3.

My first question is, why can I not use a cramfs image on the boot
partition?  Whenever I try, I get a message "VFS mounting root
filesystem (cramfs)", then "Warning: could not open initial console" and
then it complains that it can't find "init"

My second question has to do with protection on the flash chip itself. 
Whenever I try to mount a jffs image I get lots of errors saying that
Erasing failed horribly.  So I tried the erase and eraseall utilities
and get the message that I'm trying to erase a Read-Only filesystem.  My
bootloader allows me to peek and poke memory manually, so I played
around with locking / unlocking sections of flash and it seems that I
can lock and unlock blocks of flash just fine, it's just that they
aren't reported correctly by the Read Configuration command...Is this
what is meant by "Legacy lock/unlock" in the MTD debug output?  MTD
detects this at unsupported on my unit.

My third question is what's the status (if any) of jffs2 on 2.2.18
kernel?

Thanks!
Chris



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Re: A few questions (cramfs as root, flash permissions and JFFS2 on 2.2.18)

[Chris AtLee]

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> My second question has to do with protection on the flash chip itself. 
> Whenever I try to mount a jffs image I get lots of errors saying that
> Erasing failed horribly.  So I tried the erase and eraseall utilities
> and get the message that I'm trying to erase a Read-Only filesystem.  My
> bootloader allows me to peek and poke memory manually, so I played
> around with locking / unlocking sections of flash and it seems that I
> can lock and unlock blocks of flash just fine, it's just that they
> aren't reported correctly by the Read Configuration command...Is this
> what is meant by "Legacy lock/unlock" in the MTD debug output?  MTD
> detects this at unsupported on my unit.

Ok, I fixed this problem by adding a command to mtd->unlock for the
addresses corresponding to the partition I want to be read/write.  Is
this the correct solution?

Cheers,
Chris

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