Re: [PATCH v2 05/25] irqchip/gic-v3: Add FW info retrieval support

Marc Zyngier
2025-09-16T15:59:58Z

On Tue, 16 Sep 2025 16:34:13 +0100,
Jonathan Cameron <jonathan.cameron@huawei.com> wrote:
>
> On Mon, 15 Sep 2025 09:56:42 +0100
> Marc Zyngier <maz@kernel.org> wrote:
>
> > Plug the new .get_info() callback into the GICv3 core driver,
> > using some of the existing PPI affinity handling infrastructure.
> >
> > Signed-off-by: Marc Zyngier <maz@kernel.org>
> Hi Marc,
>
> Yet another trivial comment. It's one of those days it seems :)

No worries, your trivial comments are far more interesting than some
of the emails I'm otherwise getting.. ;-)

>
> > ---
> > drivers/irqchip/irq-gic-v3.c | 53 ++++++++++++++++++++++++++++++++++++
> > 1 file changed, 53 insertions(+)
> >
> > diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
> > index dbeb85677b08c..71c278ddd1e39 100644
> > --- a/drivers/irqchip/irq-gic-v3.c
> > +++ b/drivers/irqchip/irq-gic-v3.c
> > @@ -69,6 +69,8 @@ struct gic_chip_data {
> > bool has_rss;
> > unsigned int ppi_nr;
> > struct partition_desc **ppi_descs;
> > + struct partition_affinity *parts;
> > + unsigned int nr_parts;
> > };
> >
> > #define T241_CHIPS_MAX 4
> > @@ -1796,11 +1798,58 @@ static int gic_irq_domain_select(struct irq_domain *d,
> > return d == partition_get_domain(gic_data.ppi_descs[ppi_idx]);
> > }
> >
> > +static int gic_irq_get_fwspec_info(struct irq_fwspec *fwspec, struct irq_fwspec_info *info)
> > +{
> > + const struct cpumask *mask = NULL;
> > +
> > + info->flags = 0;
> > + info->affinity = NULL;
> > +
> > + /* ACPI is not capable of describing PPI affinity -- yet */
> > + if (!is_of_node(fwspec->fwnode))
> > + return 0;
> > +
> > + /* If the specifier provides an affinity, use it */
> > + if (fwspec->param_count == 4 && fwspec->param[3]) {
> > + struct fwnode_handle *fw;
> > +
> > + switch (fwspec->param[0]) {
> > + case 1: /* PPI */
> > + case 3: /* EPPI */
> > + break;
> > + default:
> > + return 0;
> > + }
> > +
> > + fw = of_node_to_fwnode(of_find_node_by_phandle(fwspec->param[3]));
>
> of_node_to_fwnode() has a note that says it'll be removed in the merge window.
> It was enough of an oddity I wondered why it existed.

Cargo culted, obviously. And yet another sign that I've been sitting
on these patches for way too long...

> Of course it did say it would be removed in the previous merge window and wasn't...
> Probably want of_fwnode_handle()

Thanks for the hint, I'll add that to v3.

M.

--
Without deviation from the norm, progress is not possible.