Subject: Linux on embedded ARM

From: "Michael Bruck" <[email-masked]>
Date: Sat, 16 May 1998 13:26:16 +0200

Is it possible to make Linux/ARM run on an embedded ARM7 (TDMI) core?
(no peripherials, only a serial console). E.g. is the basic stuff able to
deal with
ARM7?

Micha

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From: Dave Gilbert <[email-masked]>
Date: Sat, 16 May 1998 16:41:33 +0100 (BST)

> (no peripherials, only a serial console). E.g. is the basic stuff able to

The main Linux-ARM code relies on the use of the memory manager in the 
ARM 6x0,7x0,8xx,9xx and StrongARM - so the simple answer is no - it wont
run on a 7TDMI core.
I seem to remember someone was trying to do a Linux port to processors
without
memory managers (other than the ELKS port which I thuink took advantage of
the x86's segmentation); I have a vague memory of a 68K port - but can't
remember where I saw it.

Its only the memory memory (and a suitable lump of memory) that you need
for Linux; a file system is very useful as well :-)

Dave

 --------------------------------------------------------------------
/ Dr. David Alan Gilbert      | Running Linux on Alpha & ARM         \ 
\   gro.gilbert @ treblig.org | ------- Happy in hex -------         /
 \____________________________|___ http://www.treblig.demon.co.uk __/

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From: [email-masked]
Date: Sat, 16 May 1998 12:05:48 -0400 (EDT)

>  the x86's segmentation); I have a vague memory of a 68K port - but can't

	http://ryeham.ee.ryerson.ca/uClinux/

They are starting to run Linux on 3Com Pilots and other 68K based
systems without an MMU.  This combined with RT-Linux features would
make a very cool embedded RTOS!

Cheers!
Ty

-- 
Tyson D Sawyer                     Real World Interface, Inc.
Senior Systems Engineer            Robots for the Real World
[email-masked]                   http://www.rwii.com/

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From: Alan Cox <[email-masked]>
Date: Sat, 16 May 1998 20:09:10 +0100 (BST)

> the x86's segmentation); I have a vague memory of a 68K port - but can't

ucLinux. The kernel is working quite well, there are some hairy issues the
folks are still working on. The big one is that you need runtime position
independant output.

Alan

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From: "Neil A. Carson" <[email-masked]>
Date: Sat, 19 May 1990 00:23:03 +0100

> folks are still working on. The big one is that you need runtime position

Can't the ARM SDK cross-compile register relative code? This might do
the job very nicely indeed, providing the total machine memory means you
can direct-branch for function calls.

	Neil

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From: Alan Cox <[email-masked]>
Date: Mon, 18 May 1998 18:55:12 +0100 (BST)

> can direct-branch for function calls.

Not even that if you want any kind of swapping
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From: "Neil A. Carson" <[email-masked]>
Date: Tue, 19 May 1998 21:17:58 +0100

> Not even that if you want any kind of swapping

Ah, I hadn't realised the embedded Linux could swap. How does it
currently support shared libraries, presuming it can't double-map pages
it just loads the library twice. In this situation I guess a maximum of
8MB (for the branches) would be too imposing a limit.

	N.

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From: Alan Cox <[email-masked]>
Date: Mon, 18 May 1998 21:44:07 +0100 (BST)

> 8MB (for the branches) would be too imposing a limit.

The palmpilot used PalmOS style A5 relative universes  last time I looked
Im a big release behind so talk that with salt. Libraries are mmap()'d
specifying 'wherever the kernel wants to put it' which the kernel responds
to by "mapping" the page into the user space at its physical address.

This works for the frame buffer console too. Xpalmpilot anyone ?

Alan