[alsa-devel] [PATCH v3 7/8] ASoC: wm_adsp: Add a handler for the compressed IRQ

[Charles Keepax]

On Tue, Jan 05, 2016 at 02:20:25PM +0000, Mark Brown wrote:
> On Tue, Dec 29, 2015 at 03:43:13PM +0000, Charles Keepax wrote:
> > On Thu, Dec 24, 2015 at 07:31:37PM +0000, Mark Brown wrote:
> 
> > > > I am somewhat torn between a comment and renaming the function. I
> > > > will try to add some sort of reasonable comment.
> 
> > > This doesn't sound like it's really acknowledging an IRQ - you have
> > > level triggered interrupts here so if the interrupt isn't acknowledged
> > > the interrupt handler will constantly be called.
> 
> > It kinda is acking the IRQ just at the firmware level, not the
> > hardware level. The physical IRQ all gets acked through regmap
> > so that is all handled. This code here lets the firmware know,
> > which it will then use to decide whether it should send a new IRQ
> > or not.
> 
> That's not an interrupt acknowlegement, it's a request for more data.

Well a request to let us know about there being more data. We will
keep consuming data as it is generated until we reach a point where
we have less than one fragment, then we set this and wait for an
IRQ to say we have more than a fragment again.

> 
> > I could perhaps rename the function to
> > wm_adsp_buffer_request_irq? and buf->irq_ack to buf->irq_count?
> > That might make the usage a little more clear.
> 
> That might be a bit clearer, yes - it looks like this is a mailbox on
> the DSP that you're kicking?

Effectively you could think of it as a mailbox, I haven't looked
much at the framework but I suspect it is a little overkill for
what we want to do here.

Thanks,
Charles