[U-Boot] [PATCH 06/11] imx: imx-common: introduce boot auxiliary core

[Tom Rini]

On Wed, Jan 13, 2016 at 12:45:05PM -0800, Stefan Agner wrote:
> Hi,
> 
> I would like to keep the discussion going and shed some light on the
> image format introduced here, see below...
> 
> On 2016-01-07 00:38, Peng Fan wrote:
> > Hi Stefan,
> > On Wed, Jan 06, 2016 at 10:59:17PM -0800, Stefan Agner wrote:
> >>On 2016-01-04 21:56, Peng Fan wrote:
> >>> From: Peng Fan <peng.fan at nxp.com>
> >>>
> >>> To boot a auxiliary core in asymmetric multicore system, introduce the
> >>> new command "bootaux" to do it. Example of boot auxliary core from
> >>> 0x70000000 where stores the boot head information that should be
> >>> parsed by auxiliary core, "bootaux 0x70000000".
> >>
> >>This reminds me of a question which was nagging me lately:
> >>Is the M4 core of SoloX/MX7 running a boot ROM? Or who/what is "parsing
> >>the boot head information"?
> > 
> > There is no bootrom for m4 core. The bootimage for M4 contains stack
> > info and pc info. bootaux command will use the info extracted from bootimage.
> 
> 
> So the image expected by bootaux is really a raw binary image, with the
> only notion that the first two words need to be the stack pointer and
> the reset handler (firmware entry point).
> 
> U-Boot has other commands which work with "raw" images, such as the
> bootz command. The bootz command also expects a certain "raw" format,
> hence I guess it is ok to introduce something like that also for the
> auxiliary core.

I suppose my only contribution right now is that for another project
where we have U-Boot (on the M4) kicking off NuttX we've had to do a
custom command to stack pointer thing, I agree with the need to add some
way to easily kick these cases off.

-- 
Tom
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