[U-Boot-Users] ARM946, u-boot and linux

Wolfgang Denk wd at denx.de
Wed Jul 28 00:00:27 CEST 2004

Dear Shawn,

in message <c3d0340b04072711035f9822df at mail.gmail.com> you wrote:
> 1. uclinux or linux?

strictly speaking: this question is off topic on this mailing list.

> Since ARM946 has no MMU, uclinux might be a better starting point for
> porting linux to ARM946. But I have to find out the relationship

Let's rephrase it: the only chance you have on a MMU-less  system  is
by using uCLinux. For standard Linux a working MMU is mandatory.

Note that it seens that  uCLinux  has  already  been  ported  to  the

> between uclinux and linux. To my understanding, uclinux must be a
> patch to the normal linux distribution.

Not really. It's actually more of a different implemenation.  And  in
2.6 it's being merged into the standard kernel tree.

> 2. Boot loader?
> Does u-boot support ARM946? I know u-boot supports some ARM processors

Not yet, but it should be straightforward to add.

> with MMU, such as 926. Or more general question: does u-boot support
> processors without MMU? From my ppc experience I know MMU is enabled
> on u-boot.

Yes, U-Boot does support MMU-less systems (see for  example  all  the
ARM7 or StrongARM systems, or the MIPS "purple" configuration).

And you are wrong: U-Boot does NOT use the MMU on PPC. [At least  not
on  all  processors,  and  if then not for virtual memory but just to
play dirt^H^H^H^Hclever tricks with the data cache.]

> Does ELDK support ARM946? ELDK supports arm920. ELDK can be used for
> arm946 if its core is compatible with arm920's. If ELDK doesn't

You can use the cross toolchain, but the ative target tools  will  of
course not run as they require a standard Linux kernel, not uCLinux.

> support it, does it mean that I have to build the cross tool chain
> from scratch? Is there any off-shelf tool I can use? I tried to build

There are many. Did you attempt to search the Web?

> ppc cross tool chain from scratch before the crosstool came into
> being. That's not a straightforward step, actually painful.

Painful it is, indeed. 

Best regards,

Wolfgang Denk

Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at denx.de
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