Re: [PATCH v2] spi: bcm2835: Enable shared interrupt support

[Robin Murphy]

On 2020-06-15 18:04, Florian Fainelli wrote:
> On 6/15/2020 10:00 AM, Mark Brown wrote:
> > On Mon, Jun 15, 2020 at 09:34:58AM -0700, Florian Fainelli wrote:
> >
> > > OK, so this has been dropped for spi/for-next right? How do we move from
> > > there?
> >
> > Well, I actually have it queued up for applying so unless I pull it
> > before my scripts get that far through the stuff I queued over the merge
> > window it'll go in (I dropped it due to it not being a bugfix).  If it
> > were me I'd go with the two instruction hit from checking the flag TBH
> > but otherwise I guess __always_inline should work for compilers that
> > misoptimize.  None of this is getting in the way of the framework so if
> > everyone involved in the driver is happy to spend time optimising it
> > and dealing with the fragility then it's fine by me.
>
> OK, how about I send you an increment patch (would a fixup be okay?)
> that adds __always_inline since we know from this thread that some
> compilers may mis-optimize the function inlining?

Now that I've been inclined to go and look up the documentation, are we 
sure this so-very-contentious check is even correct? From my reading of 
things we're checking whether the RXR interrupt function is *enabled*, 
which still says nothing about whether either condition for the 
interrupt being *asserted* is true (RXR = 1 or DONE = 1). Thus if more 
than one SPI instance is active at once we could still end up trying to 
service an IRQ on a controller that didn't raise it.

Robin.