Question regarding mounting CRAMFS and JFFS2 from a single flash chip on ucLinux

[Todd Poynor]

Sreecharan Sivadevuni wrote:
> I am using an arm processor based development board on
> which there is an Intel E28F320(NOR) flash chip which
> is of 4MB. ...
> my flash is getting detected on 'cfi_probe'. But when
> I am trying to mount JFFS2(or trying to write to )
> '/dev/mtdblock0'(at 0x00600000) I am getting an error
> that it is a readonly file system. The error as it is
> printed on console is "-EROFS. Is the Sector Locked ?"
> This is coming from file 'cfi_cmdset_0001.c' from
> function 'do_erase_one_block'. This is despite that I
> have made my JFFS2 partition as MTD_WRITEB_WRITEABLE
> in 'physmem.c' file.

Your flash chips probably power up with all blocks locked, and blocks to 
be written must be unlocked first.  Can use flash_unlock /dev/mtdX prior 
to mounting the writeable fs, or various ways of unlocking blocks at 
chip probe or maps setup time have been discussed in the archives.

-- 
Todd