Re: [PATCH v2 07/19] remoteproc: Add new resource type for resource table spare bytes

[loic pallardy]

On 09/16/2016 07:12 PM, Bjorn Andersson wrote:
> On Fri 16 Sep 02:02 PDT 2016, loic pallardy wrote:
>
> > On 09/15/2016 07:54 PM, Bjorn Andersson wrote:
> > > On Wed 31 Aug 13:50 PDT 2016, Loic Pallardy wrote:
> > >
> > > > To allow resource appending to an existing resource table,
> > > > remoteproc framework should get information about resource
> > > > table spare area. With current resource table construction,
> > > > remoteproc is not able to identify by itself any free location.
> > > > This patch introduces a new resource type named RSC_SPARE which
> > > > allows firmware to define room for resource table extension.
> > > > Defined spare area will be used by remtoreproc to extend resource
> > > > table.
> > >
> > > We don't need a dummy type for keeping track of the available room in
> > > the resource table in the loaded firmware. All we need to do is to look
> > > at the sh_size of the .resource_table section, which actually is what's
> > > returned in tablesz.
> > This is the size of the .resource_table section. Doesn't means that only
> > resource table is stored in.
>
> I'm not sure I'm getting the details of what you're saying here. Do you
> mean that there could be other things in the resource_table section or
> just the fact that it being a section doesn't give any information about
> how much space this thing will have in loaded form.
>
> > Today this is the assumption and we force firmware to respect this.
>
> I find it unfortunate that this was put in section and that we just have
> to make assumptions on how this projects onto the loaded form.
>
> > > So the spare size is the difference between tablesz and the end of the
> > > last resource and if you need you can pad this when composing the
> > > firmware.
> > Proposal was to clearly identify the area for extension (whatever
> > .resource_table section is done). But if you agree on the fact
> > .resource_tabel section constains only resource table and eventualy room for
> > extension, I can indeed simply room detection.
>
> Could you describe your use case for programmatically generate a
> resource table for a firmware without a .resource_table? I would like to
> understand the contract between the driver and the firmware when it
> comes to what should go into the resource table.

No I always consider .resource_table section.
You answer to my point just above. .resource_table section must contain 
only the resource table and nothing else. I'm fine with that.

I'll revert RSC_SPARE type.

Regards,
Loic
> Regards,
> Bjorn