[Sound-open-firmware] [PATCH v3 5/5] vhost: add an RPMsg API

[Vincent Whitchurch]

On Thu, Jun 18, 2020 at 04:14:12PM +0200, Guennadi Liakhovetski wrote:
> On Thu, Jun 18, 2020 at 03:52:42PM +0200, Vincent Whitchurch wrote:
> > Note that "the Linux side" is ambiguous for AMP since both sides can be
> > Linux, as they happen to be in my case.  I'm running virtio/rpmsg
> > between two physical processors (of different architectures), both
> > running Linux.
> 
> Ok, interesting, I didn't know such configurations were used too. I understood 
> the Linux rpmsg implementation in the way, that it's assumed, that the "host" 
> has to boot the "device" by sending an ELF formatted executable image to it, is 
> that optional? You aren't sending a complete Linux image to the device side, 
> are you?

I do pack the zImage, the dtb, and the initramfs into an ELF (along with
a tiny "bootloader" with just a handful of instructions), but the
remoteproc framework is not tied to the ELF format since ->parse_fw()
and friends are overridable by the remoteproc driver.

> > virtio has distinct driver and device roles so the completely different
> > APIs on each side are understandable.  But I don't see that distinction
> > in the rpmsg API which is why it seems like a good idea to me to make it
> > work from both sides of the link and allow the reuse of drivers like
> > rpmsg-char, instead of imposing virtio's distinction on rpmsg.
> 
> Understand. In principle I'm open to this idea, but before I implement it it 
> would be good to know what maintainers think?

Certainly.