DOC2000 support for a custom PPC750 board

DOC2000 support for a custom PPC750 board

[Boris Bulkin]

Hi!

Could anyone please advise something on the following issue?

I'm working on port of a firmware program to a PPC750-based board, and I
need to support for booting Linux from a DOC2000 partition in the
firmware. I'm thinking of using existing MTD stuff as a base for my
efforts. Once the firmware is working, I'll need to support DOC in Linux
too.

I'm new to the MTD project, so any information will be very appreciated.
What is the current state of MTD support for DOC? Do MTD DOC drivers
require any firmware from M-Sys, or does MTD provide its own DOC
firmware? Then, I know that M-Systems  suggests running its DOS-based
tools for partitioning and formatting a DOC device. Are there any
open-source replacements for them?

Of course, my firmware program will be open-source, too.

Many thanks in advance.
Boris

Re: DOC2000 support for a custom PPC750 board

[David Woodhouse]

boris@emcraft.ru said:
>  I'm new to the MTD project, so any information will be very
> appreciated. What is the current state of MTD support for DOC? 

It works, for the DiskOnChip 2000 and DiskOnChip Millennium. Not the
Millennium Plus. It doesn't do sane wear-levelling though. That's left as an
exercise for the reader. Pointers and CVS access will happily be given to
anyone who looks serious about doing it.


> Do MTD DOC drivers require any firmware from M-Sys, or does MTD provide
> its own DOC firmware? 

The DiskOnChip requires no firmware. It is not an intelligent device. 
What's normally referred to as the DiskOnChip 'firmware' is the BIOS 
extension which installs a driver which hooks the PC INT 13h disk service 
interrupt and hence makes DOS and LILO work. I assume you don't want that :)

> Then, I know that M-Systems  suggests running its
> DOS-based tools for partitioning and formatting a DOC device. Are
> there any open-source replacements for them?

There is nftl_format.c which performs the basic function of creating an 
NFTL on the raw flash. NFTL is the translation layer used on the DiskOnChip 
devices to emulate a normal block device. It is preferred to use the DOS 
utilities because their response to finding bad blocks has been far better 
tested. But nftl_format should be OK.

--
dwmw2

Re: DOC2000 support for a custom PPC750 board

[Boris Bulkin]

David,

Thank you very much for the quick response. The information you've given is an
exelent help for me to get started.

One more question: from the M-Sys documents I understand there can be two types
of partitions on a DOC device, binary and NFTL. Binary is supposed to store an
OS image, and NFTL be used as a filesystem. Are there any MTD tools for
creating and reading/writing binary DOC partitions?
Sorry if it sonds silly. I'm not very familiar with DOC and MTD.

Thanks,
Boris

David Woodhouse wrote:

> boris@emcraft.ru said:
> >  I'm new to the MTD project, so any information will be very
> > appreciated. What is the current state of MTD support for DOC?
>
> It works, for the DiskOnChip 2000 and DiskOnChip Millennium. Not the
> Millennium Plus. It doesn't do sane wear-levelling though. That's left as an
> exercise for the reader. Pointers and CVS access will happily be given to
> anyone who looks serious about doing it.
>
> > Do MTD DOC drivers require any firmware from M-Sys, or does MTD provide
> > its own DOC firmware?
>
> The DiskOnChip requires no firmware. It is not an intelligent device.
> What's normally referred to as the DiskOnChip 'firmware' is the BIOS
> extension which installs a driver which hooks the PC INT 13h disk service
> interrupt and hence makes DOS and LILO work. I assume you don't want that :)
>
> > Then, I know that M-Systems  suggests running its
> > DOS-based tools for partitioning and formatting a DOC device. Are
> > there any open-source replacements for them?
>
> There is nftl_format.c which performs the basic function of creating an
> NFTL on the raw flash. NFTL is the translation layer used on the DiskOnChip
> devices to emulate a normal block device. It is preferred to use the DOS
> utilities because their response to finding bad blocks has been far better
> tested. But nftl_format should be OK.
>
> --
> dwmw2

Re: DOC2000 support for a custom PPC750 board

[David Woodhouse]

boris@emcraft.ru said:
>  One more question: from the M-Sys documents I understand there can be
> two types of partitions on a DOC device, binary and NFTL. Binary is
> supposed to store an OS image, and NFTL be used as a filesystem. Are
> there any MTD tools for creating and reading/writing binary DOC
> partitions? Sorry if it sonds silly. I'm not very familiar with DOC
> and MTD.

By 'binary partitions' they presumably mean data stored directly on the 
flash chips. NFTL is a kind of pseudo-filesystem which is used to emulate a 
block device - you then put normal filesystems on top of that emulated 
block device. 

Yes, we have programs which will write data to the raw flash. You just open 
/dev/mtd0, use the MEMERASE ioctl for the region you want to overwrite 
and then write to it. The doc_loadbios program was used for putting Grub in 
place of the normal firmware. 

--
dwmw2

RE: DOC2000 support for a custom PPC750 board

[Bao C. Ha]

> The DiskOnChip requires no firmware. It is not an intelligent device. 
> What's normally referred to as the DiskOnChip 'firmware' is the BIOS 
> extension which installs a driver which hooks the PC INT 13h 
> disk service 
> interrupt and hence makes DOS and LILO work. I assume you 
> don't want that :)

Can the firmware boot into LILO directly?  Or it requires the patched
lilo-mtd in the patches subdirectory?

I have been under the impression that you need lilo-mtd to boot the
DiskOnChip.  However, the lilo-mtd patch is dated March of 2000.

Thanks.
Bao

 

Re: DOC2000 support for a custom PPC750 board

[David Woodhouse]

baoha@sensoria.com said:
>  Can the firmware boot into LILO directly?  Or it requires the patched
> lilo-mtd in the patches subdirectory?

> I have been under the impression that you need lilo-mtd to boot the
> DiskOnChip.  However, the lilo-mtd patch is dated March of 2000. 

I've never used the patched LILO, but I believe the only changes are that 
it recognises the 'root=/dev/nftla' device and sets the device number 
accordingly, and that it can deal with the fact that the M-Systems BIOS 
extension has eaten a huge chunk of sub-640K RAM. The latter may no longer 
be required with a newer LILO anyway, and the former can be worked around 
by using 'append="root=/dev/nftla"' instead of just 'root=', just as with 
other device names that LILO doesn't know about.


--
dwmw2