Re: [PATCH 1/1] perf/arm-cmn: Add more bits to child node address offset field

[Ilkka Koskinen]

Hi Robin,

On Wed, 21 Sep 2022, Robin Murphy wrote:
> On 08/08/2022 8:54 pm, Ilkka Koskinen wrote:
> > CMN-600 uses bits [27:0] for child node address offset while bits [30:28]
> > are required to be zero.
> >
> > For CMN-650, the child node address offset field has been increased
> > to include bits [29:0] while leaving only bit 30 set to zero.
> >
> > Let's include the missing two bits and assume older implementations
> > comply with the spec and set bits [29:28] to 0.
>
> Just to add that other users have run into this as well, so getting it 
> applied as a fix would be just lovely. Technically I think it's:
>
> Fixes: 60d1504070c2 ("perf/arm-cmn: Support new IP features")

Ah, that's true. Should I resend the patch with your reviewed-by and the 
fixes lines?

Cheers, Ilkka


> Cheers,
> Robin.
>
> > Signed-off-by: Ilkka Koskinen <ilkka@xxxxxxxxxxxxxxxxxxxxxx>
> > ---
> >
> > I have tested this patch on CMN-600 and CMN-650.
> >
> > drivers/perf/arm-cmn.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/perf/arm-cmn.c b/drivers/perf/arm-cmn.c
> > index 80d8309652a4..b80a9b74662b 100644
> > --- a/drivers/perf/arm-cmn.c
> > +++ b/drivers/perf/arm-cmn.c
> > @@ -36,7 +36,7 @@
> >   #define CMN_CI_CHILD_COUNT		GENMASK_ULL(15, 0)
> >   #define CMN_CI_CHILD_PTR_OFFSET		GENMASK_ULL(31, 16)
> >   -#define CMN_CHILD_NODE_ADDR		GENMASK(27, 0)
> > +#define CMN_CHILD_NODE_ADDR		GENMASK(29, 0)
> >   #define CMN_CHILD_NODE_EXTERNAL		BIT(31)
> >     #define CMN_MAX_DIMENSION		12