Re: Linux support for MPC859T processor

["Frank Robbins" <Frank.Robbins@Analogue-Micro.com>]

There is no RTC in terms of the normal 32Khz input now on the HIP6W family
Also the chip needs to come up to 40 Mhz operation after reset different
from the 860 15 Mhz minimum.

Careful debugging....

RedBoot is nice to as a loader

Frank

----- Original Message -----
From: "Conn Clark" <clark@esteem.com>
To: "Dmytro Bablinyuk" <dmytro.bablinyuk@tait.co.nz>
Cc: "May Ling List" <linuxppc-embedded@lists.linuxppc.org>
Sent: Wednesday, April 02, 2003 7:15 PM
Subject: Re: Linux support for MPC859T processor


>
> From what you describe of the MPC859T I would say that porting the
> kernel may not be too difficult. The motorola web page claims that the
> MPC859T has a RTC. It sound like it is just a stripped down MPC866 with
> just one SCC and one FEC. Without a data book its hard to say what may
> need to change in the kernel to make it work, but I doubt it will be much.
>
> Unless the MPC859T has introduced new instructions assembly should be
> identical to the MPC860.I also doubt that you would need to write a
> single line of assembly. Perhaps you should look into 'PPCBoot' (
> http://ppcboot.sourceforge.net ) or 'Das U Boot' (
> http://sourceforge.net/projects/u-boot/ ) for starters. PPCBoot was a
> godsend and abstracted a lot of the porting head aches for us.
>
> In designing a propretary design I would suggest you look at the
> kernel code and try and map your io pins in a similar manner as some
> supported board. It eases the amount of work needed to port the kernel.
> An In Circuit Emulator or BDM/JTAG debugger can be worth its weight in
> gold in bringing up a propretary design. Just beware that quite a few
> will not work once you get Linux up and going on your board. You also
> may want the initial prototype design to accept socketed flash as well
> as the rom/flash you intend on using in production. Sometimes getting a
> BDM/JTAG debugger or ICE to do it is a major pain. A bootstrap header
> that allows you to power and program the flash in the circuit might be
> better because it can aid in production. Its just alot harder to design.
>
> Good Luck and have fun ripping your hair out.
>
> Conn
>
> Dmytro Bablinyuk wrote:
> >
> > Yes, we are ready to have a big pain with porting, and we know that
> > there is a risk which we are trying to reduce.
> > Would the MontaVista give some hands on, for example, how to an internal
> > RTC function on '860 represent in the kernel ('859 doesn't have RTC
> > func) and how it's affect the kernel and how it could be "removed" etc?
> > So, we at least would know what shall we look for.
> > Also could you please tell me how assembler on '860 different from '859?
> > Would this affect booting?
> >
> >> Honestly, I don't know my guess is close to non to a small handful...
> >> But I am truely a novice when it comes to CPU/board bringup.. (I've
> >> assisted in it, but my expertise and history is in userspace
> >> development.)  The things that can take massive amounts of time on
> >> these new processors/boards are hardware bugs (cpu and board) as well
> >> as device drivers for new on chip devices.  I have seen more then one
> >> engineer going bald due to hardware bugs, especially a board that the
> >> customer said "But it runs VxWorks, why doesn't it run Linux?"...
> >>
> >>> Not a lot of our people experienced in PPC assembler (including
myself).
> >>> Actually not a lot experienced with PPC at all.
> >>> Roughly, from your point of you, how major changes in the kernel
> >>> could be? Just your subjective opinion.
> >>>
> >>>> On userspace basis.. the 860 and the 859 are fully compatable.. The
> >>>> need for
> >>>> 859T changes may be in the kernel.  So anyone who sells/supports an
> >>>> 860 based
> >>>> system can support your needs for application level.  (That includes
> >>>> MontaVista.)
> >>>>
> >>>> The linux kernel of course is a different level of complexity.
> >>>>
> >>>>> We are trying to find a linux supplier who supports Motorola MPC859T
> >>>>> processor (actually it will be processor from Motorola but our
custom
> >>>>> board).
> >>>>
> >>>>
> >
> >
> >
> >
> >
>
>
> --
>
> *****************************************************************
>    If you live at home long enough, your parents will move out.
>   (Warning they may try to sell their house out from under you.)
> *****************************************************************
>
> Conn Clark
> Engineering Stooge clark@esteem.com
> Electronic Systems Technology Inc. www.esteem.com
>
>
>


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