[libcamera-devel] [EXTERNAL] Re: Porting libCamera in to RDKC

[Laurent Pinchart]

Hi Peter,

On Tue, Jun 30, 2020 at 10:58:28AM +0100, Peter Griffin wrote:
> On Wed, 10 Jun 2020 at 00:48, Laurent Pinchart wrote:
> > On Tue, Jun 09, 2020 at 11:34:59PM +0000, Raj, Khem wrote:
> >> Is it specific to soc ? We can also use rpi0 as reference
> >
> > The overall camera stack architecture shouldn't depend on a particular
> > platform, but libcamera has SoC-specific support. We do support
> > Raspberry Pi platforms, but out team has only tested Raspberry Pi 3 and
> > 4. I believe the Raspberry Pi 0 should be supported in theory, but if I
> > recall correctly the slower ARM core may make it a bit more challenging
> > in practice.
> >
> > That being said, enabling libcamera support for the Ambarella SoCs would
> > be interesting. It would require Ambarella-specific code in libcamera,
> > which in turns would require kernel drivers to be submitted to the
> > linux-media mailing list for upstream.
> 
> I did a quick bit of research into current Ambrella SoC support. It is
> used in quite a few products like Nest Camera, so the GPL kernel
> source is available from here for example
> https://nest.com/legal/compliance/.
> 
> But it is a rather ancient 2.6.38 kernel. So a fair bit of work would
> be required just to port & upstream basic SoC support, migrate to DT
> etc, before starting to look at anything camera/media related. 

And even without looking, I'm pretty sure that the ISP driver is either
fully in userspace, just has a simple shim layer in the kernel, or is a
closed-source module. It's probably unusable in any case.

> Starting the RDKC integration of libcamera on the RPi3/4 platform
> where much of the kernel, media drivers and libcamera work already
> exists would be much quicker.

I'd say it wouldn't just be much quicker, it's the only feasible option
until Ambarella starts having a real interest in Linux :-)

> at *@comcast.com guys - meet Madhavan who is also working on RDKC topics
> on RPi platform. It seems it maybe worth a sync with you folks to avoid
> duplicating effort.
> 
> >> On Tuesday, June 9, 2020 8:44:32 AM, Dubey, Vijayanand wrote:
> >>>
> >>> Hi Laurent
> >>> It's my bad, Ambarella does not have Upstream Linux Kernel Support.
> >>>
> >>> On 6/8/20, 1:06 PM, "Dubey, Vijayanand" wrote:
> >>>> Hi Laurent
> >>>> As per my understanding it does.. I posted the same question to SoC vendor
> >>>> and will get back to you as soon as I get the answer from them.
> >>>>
> >>>> On 6/8/20, 11:02 AM, "Laurent Pinchart" wrote:
> >>>>> On Mon, Jun 08, 2020 at 02:56:05PM +0000, Dubey, Vijayanand wrote:
> >>>>>> Hi Laurent
> >>>>>> Here are the current  RDKC cameras' SoC datasheets.
> >>>>>> https://urldefense.com/v3/__https://www.ambarella.com/wp-content/uploads/S2Lm-Product-Brief-Final.pdf__;!!CQl3mcHX2A!ROSmZUzjossuIm3lDwqxahUsd2HOVTGF_wZhzZsaJbZxOCNCdhBvBmGPTRsYWcxau11N$ (xCAM/iCAM2)
> >>>>>> https://urldefense.com/v3/__http://www.ambarella.com/wp-content/uploads/S3L-Product-Brief.pdf(xCAM2)__;!!CQl3mcHX2A!ROSmZUzjossuIm3lDwqxahUsd2HOVTGF_wZhzZsaJbZxOCNCdhBvBmGPTRsYWUHTZhNc$
> >>>>>> https://urldefense.com/v3/__https://www.ambarella.com/wp-content/uploads/S5L-Product-Brief.pdf(doorbell)__;!!CQl3mcHX2A!ROSmZUzjossuIm3lDwqxahUsd2HOVTGF_wZhzZsaJbZxOCNCdhBvBmGPTRsYWRqWEeYb$
> >>>>>
> >>>>> Thank you.
> >>>>>
> >>>>>> They are fully ARM SoCs and we do have upstream Linux kernel support
> >>>>>> for these products.
> >>>>>
> >>>>> I don't see any device tree file for these SoCs in the upstream kernel.
> >>>>> Am I missing something obvious ?

-- 
Regards,

Laurent Pinchart