> On September 6, 2006 07:10 am, Guillermo Prandi wrote:
>> > P.S. I really don't understand why TS didn't just define the FIS
>> > directory as follows:
>> >
>> > TS-BOOTROM 0x6000-0000 - 0x6000-3fff
>> > LinuxFS 0x6000-4000 - 0x6....
>> > RedBoot 0x6....
>> > zimage ...
>> > RedBoot config ...
>> >
>> > If they did it that way, it would be very easy to use RedBoot to
>> > replace the LinuxFS with whatever you wanted. Instead of course
>> they
>> > grouped the TS-BOOTROM and the LinuxFS under "(reserved)" and you
>> > can't touch it with RedBoot. So we have to become RedBoot source
>> > hackers to do anything non-standard with the board.
The filesystem is defined the way it is because the reserved space contains
data which RedBoot doesn't know how to handle. For instance, the Linux
partition uses the YAFFS or YAFF2 filesystem. If RedBoot were to naively
write to this area, not only would the data be in the wrong format, but out
of band data which YAFFS requires would not be written.
>> Another reason may come from the fact that the MTD driver on the TS
>> kernel does not parse the RedBoot partition at all, but has a
>> hardcoded map of the partitions instead. If you would change the
>> partition layout, the /dev/mtd devices would stop working (At least
>> on the TS-11 kernel version I'm using).
>>
I think you've got this backwards... Redboot sits in its own partition which
is (currently) hard-coded by the MTD driver. It is true however that MTD
has no knowledge of the filesystem used by RedBoot (fis dir).
>> Guille
>>
>
> TS loads the 256KB RedBoot partition into memory with no ECC correction.
> Thats
> pretty risky. The SerialBlaster bootloader loads Redboot with ECC.
This is not entirely true... There is ECC checking and correction
implemented in RedBoot. Also, when we added support for 2K sector size NAND
flash, code was added to deal with and work around bad blocks, but this is
in the RedBoot partition *only* and is an entirely different scheme from
what a filesystem like YAFFS uses.
>
> Redboot seems to have jffs2. Maybe that could be used to store the linux
> kernel or BSD kernels. But it looks like it need some work:
>
> ecos/packages/fs/jffs2
>
The file "ecos/packages/redboot/current/src/flash.c" contains most of the
logic for the fis commands, you might want to look at that.
Michael
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