Re: [PATCH v3 15/22] firmware: arm_scmi: abstract mailbox interface

From: Jassi Brar
Date: Fri Oct 06 2017 - 09:34:21 EST

On Fri, Oct 6, 2017 at 6:57 PM, Sudeep Holla <sudeep.holla@xxxxxxx> wrote:
> On 06/10/17 12:34, Jassi Brar wrote:
>> On Wed, Oct 4, 2017 at 5:02 PM, Sudeep Holla <sudeep.holla@xxxxxxx> wrote:
>>> Also, I have added shim only for specific controllers that need them.
>>> E.g. ARM MHU as Jassi disagreed to add doorbell mechanism to that.
>>> mbox_if provides default implementation that just calls direct mailbox
>>> APIs.
>> Yeah you could hack away the MHU driver to make your life easy at the
>> cost of duplicated code and extra DT bindings, but for a moment think
>> what if your development platform wasn't MHU but, say, Rockchip
>> mailbox controller?
> As mentioned before I understand your concern. But the point is this
> needs to be replicated with each protocol on that controller.
Only generic protocols need to have a platform specific transport
layer. There's no escaping that.

> So as Arnd
> pointed out we can reduce that by generalizing common things like doorbell.
Rockchip, and most other controllers, has no "doorbell". And yet each
is perfectly capable of supporting SCMI.
Looking forward to your "generalised doorbell".