From: Ohad Ben-Cohen
Sent: Saturday, June 25, 2011 6:12 PM

Hi Stephen,

On Fri, Jun 24, 2011 at 11:16 PM, Stephen Boyd [off-list ref] wrote:

quoted

Instead of devising a new firmware format, we decided
to just stick with elf and parse the headers in the kernel because we
needed them for authentication anyway. Is this reason enough to move to
an ELF format instead?

I think that consolidation of code is enough reason to make an effort.
I know that our firmware format was chosen for simplicity, but I'm not
sure if we have the tools yet to build standard ELF files for the
remote processors (IIRC it's in the works though). I'll let Mark
comment this one.

Yes, we are converting from "standard" ELF to the simple format. I've used the
GNU binutils to work with our ELF files. There were a few motivations:

1. Concern about complexity of parsing ELF files in kernel; however, the PIL
implementation looks pretty clean to me.

2. We added a special section (resource table) that is interpreted as part
of the loading process. The tool that generates our simple format just
recognizes a named section (".resource_table"), so perhaps that could be
done with the PIL ELF loader.

3. Smaller firmware file sizes. Our ELF files are large relative to the
payload, but this might be addressed by a better ELF "strip" utility.

quoted

Another difference is inter-processor dependencies. For example, on
msm8660 the modem can't boot until the dsp has been booted. I suppose we
could hide this detail in the platform specific get() implementation by
calling rproc_get() on the dependent processor (hopefully no locking
issues arise). I'd rather have it built into the core though as it isn't
really specific to the hardware.

No problems, I'm sure we can solve this one easily.

quoted

If we can resolve these differences I think we can easily support remote
processor boot on MSM via remoteproc.

That'd be very cool, I sure do hope we can work together.

Yes, I hope we can merge our efforts on PIL and remoteproc since they seem
quite close in function and design.

Mark