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Dmytro Bablinyuk | 2 Apr 2003 04:31
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Linux support for MPC859T processor


We are trying to find a linux supplier who supports Motorola MPC859T
processor (actually it will be processor from Motorola but our custom
board).
We have contacted MontaVista and we discovered that the nearest
processor they support is MPC860.
Also we discovered that:

An MPC860 based board might be suitable for initial S/W development
purposes as the chip is very similar to the MPC859T we intend to use.
There are 7 variants of the '860 with different cache sizes and serial
communications capabilities.
The main differences between the '860 and the '859T that I am aware of are:

1.    The '860 runs at approximately half the speed of the '859T.
2.    The clocking generator for the 860 would require a different
configuration to the the '859 as a consequence of above.
3.    The '860 has an internal RTC function whereas the '859T does not.
4.    The '859T has a dedicated 10/100Mbps ethernet MAC whereas the '860
has to use the serial communication controllers for ethernet operations.
The available ethernet speeds depend on the particular variant of the '860.
Note some of the '860 variants include a dedicated 10/100Mbps ethernet MAC.
5.     The '859T core operates off a lower voltage (1.8V) for power
saving whereas the '860 core runs off a 3.3V supply.
Consequently the '860 draws approximately 2x the power of the '859T.

Apart from the differing core voltages the '860 and '859T appear to be
pin compatible

* Could somebody please give me an advice on how much S/W work might be
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Mark Hatle | 2 Apr 2003 04:45

Re: Linux support for MPC859T processor


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.

--Mark

Dmytro Bablinyuk wrote:
>
> We are trying to find a linux supplier who supports Motorola MPC859T
> processor (actually it will be processor from Motorola but our custom
> board).
> We have contacted MontaVista and we discovered that the nearest
> processor they support is MPC860.
> Also we discovered that:
>
> An MPC860 based board might be suitable for initial S/W development
> purposes as the chip is very similar to the MPC859T we intend to use.
> There are 7 variants of the '860 with different cache sizes and serial
> communications capabilities.
> The main differences between the '860 and the '859T that I am aware of are:
>
> 1.    The '860 runs at approximately half the speed of the '859T.
> 2.    The clocking generator for the 860 would require a different
> configuration to the the '859 as a consequence of above.
> 3.    The '860 has an internal RTC function whereas the '859T does not.
> 4.    The '859T has a dedicated 10/100Mbps ethernet MAC whereas the '860
> has to use the serial communication controllers for ethernet operations.
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Dmytro Bablinyuk | 2 Apr 2003 05:05
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Re: Linux support for MPC859T processor


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).
>

** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
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Mark Hatle | 2 Apr 2003 05:13

Re: Linux support for MPC859T processor


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?"...

--Mark

Dmytro Bablinyuk wrote:
> 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).
>>
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Dmytro Bablinyuk | 2 Apr 2003 05:39
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Re: Linux support for MPC859T processor


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.)
(Continue reading)

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Conn Clark | 2 Apr 2003 20:15
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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
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Frank Robbins | 3 Apr 2003 10:59

Re: Linux support for MPC859T processor


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 <at> esteem.com>
To: "Dmytro Bablinyuk" <dmytro.bablinyuk <at> tait.co.nz>
Cc: "May Ling List" <linuxppc-embedded <at> 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
(Continue reading)

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