Re: [RFC] dt-bindings: mailbox: add doorbell support to ARM MHU

[Viresh Kumar]

On 28-05-20, 13:20, Rob Herring wrote:
> Whether Linux 
> requires serializing mailbox accesses is a separate issue. On that side, 
> it seems silly to not allow driving the h/w in the most efficient way 
> possible.

That's exactly what we are trying to say. The hardware allows us to
write all 32 bits in parallel, without any hardware issues, why
shouldn't we do that ? The delay (which Sudeep will find out, he is
facing issues with hardware access because of lockdown right now)
which may be small in transmitting across a mailbox becomes
significant because of the fact that it happens synchronously and the
receiver will send some sort of acknowledgement (and that depends on
the firmware there) and the kernel needs to wait for it, while the
kernel doesn't really need to. There is no reason IMHO for being
inefficient here while we can do better.

-- 
viresh