topic Re: XIP on imx? in i.MX Processors

XIP on imx?

RandyKrakora — Fri, 14 Sep 2012 15:28:35 GMT

Has anyone successfully built and run a XIP kernel on an imx part? We can build it with ltib ( hopefully we got it right ), but loading and running haven't been successful ( so maybe using mkImage is bad? Or our uboot command is not right? ).

Anyone have experience with it?

Regards,
Randy Krakora

Re: XIP on imx?

RobertSchwebel — Fri, 14 Sep 2012 16:08:32 GMT

Hi,

Why do you want to do XIP? The only usecase for XIP I have seen so far was while running Linux on a very ressource constrained Cortex-M3. On any other device, XIP should not be necessary.

Regards,

Robert

Re: XIP on imx?

RandyKrakora — Fri, 14 Sep 2012 16:14:52 GMT

It's an experiment to compare performance with and without it ( on imx25 ), just to prove that it may not be a good choice. Sorry we can't just take word that it's a bad idea, we have to see for ourselves. :smileyhappy:

Regards,
Randy Krakora

Re: XIP on imx?

RobertSchwebel — Fri, 14 Sep 2012 16:22:26 GMT

The issue is that almost nobody out there uses it, so you are entering a dead end. Some time ago there was even a discussion to remove the feature from the kernel.

What kind of "performance" do you have in mind? CPUs in the MX25 range can be booted from power-good into userspace in about 700 ms.

Re: XIP on imx?

RandyKrakora — Fri, 14 Sep 2012 16:27:35 GMT

That's what we've found, there's no clear instructions on how to do it.

Actually I misspoke when I said performance, we are looking at increasing available RAM and XIP is a way to do that, but if the performance with XIP is too bad, obviously we won't keep it enabled.

Regards,

Randy Krakora