On 27 January 2012 00:33, Rusty Russell <rusty at rustcorp.com.au> wrote:
> Peter Maydell wrote:
>> Anyway, if we would otherwise die horribly later on we should
>> catch these cases, but it would be good to have at least a comment
>> saying that these are implementation limitations rather than
>> architectural ones.
>
> Good point. ?If we add an "supported" bit to each irq, we could do weird
> things, but presumably ->num_irq would still correspond to
> ITLinesNumber.
>
> I don't want to put too much of an essay in there. ?How's this:
>
> ? ? ? ?/* ITLinesNumber is represented as (N - 32) / 1. ?See
> ? ? ? ? ?gic_dist_readb. */
> ? ? ? ?if (s->num_irq < 32 || (s->num_irq % 32)) {
> ? ? ? ? ? ? ? ?hw_error("%u interrupt lines unsupported: not divisible by 32\n",
> ? ? ? ? ? ? ? ? ? ? ? ? num_irq);
I think that's a notch too terse for my taste. How about:
/* ITLinesNumber is represented as (N - 32) / 1 (see
* gic_dist_readb) so this is an implementation imposed
* restriction, not an architectural one:
*/
thanks
-- PMM
