Intel Edison Initial Assessment

[Joel Sherrill]

Hi

Some initial notes as Jeff and I investigate bringing up
RTEMS on an Intel Edison. The short answer is that the
Intel Edison is not going to work out of the box with our
PC BSP.  I am really hoping others have ideas and quick
suggestions so it has a chance of working next week
at the FSW. :)

+ SoC documentation won't be out until later this month.

+ Has U-Boot and doesn't appear to have a 16-bit mode at all.

+ Looks like U-Boot will want a binary image to boot.

+ There is a comment in the Intel forums that the PCI
configuration space is memory mapped and not IO mapped
like a regular PC.

http://forum.osdev.org/viewtopic.php?f=1&t=28707

This means the PCI initialization and support code needs to
be different for Edison from other PCs.

+ All serial ports are on the PCI bus. It looks like the PCI
layout is constant so for a start, I am hacking a simple
polled driver for one UART and go from there. U-Boot
initializes it so I can ignore that part. This should be
enough to at least temporarily get around the lack of PCI
config space code.

+ There is a watchdog on it that needs to be disabled apparently.

+ Looks like it doesn't have a legacy i8254 timer and has an APIC.

Not sure what else lurks. But unless someone drops an APIC clock
driver on me, I think getting a booting hello world is a nice goal for
next week.

Thoughts? Ideas?

-- 
Joel Sherrill, Ph.D.             Director of Research & Development
joel.sherrill at OARcorp.com        On-Line Applications Research
Ask me about RTEMS: a free RTOS  Huntsville AL 35805
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