[PATCH 2/2] irqchip/gic-v5: Fix standalone IRSes OF probe

[Lorenzo Pieralisi]

An IRS is architecturally allowed to be standalone, namely, with no
direct CPUs connections. Make sure such configuration is allowed on
OF firmware by skipping "cpus" and "arm,iaffids" IRS node properties
parsing if they are not present so that the IRS configuration can
complete successfully.

Fixes: 5cb1b6dab2de ("irqchip/gic-v5: Add GICv5 IRS/SPI support")
Signed-off-by: Lorenzo Pieralisi <lpieralisi@xxxxxxxxxx>
Cc: Sascha Bischoff <sascha.bischoff@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Marc Zyngier <maz@xxxxxxxxxx>
---
Please do not consider this patch before we agree on what's best
for DT bindings in patch 1, thanks.
---
 drivers/irqchip/irq-gic-v5-irs.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/irqchip/irq-gic-v5-irs.c b/drivers/irqchip/irq-gic-v5-irs.c
index b3feb6340b59..53639e6f85bd 100644
--- a/drivers/irqchip/irq-gic-v5-irs.c
+++ b/drivers/irqchip/irq-gic-v5-irs.c
@@ -609,6 +609,10 @@ static int __init gicv5_irs_of_init_affinity(struct device_node *node,
 	u16 iaffid_mask = GENMASK(iaffid_bits - 1, 0);
 	int ret, i, ncpus, niaffids;
 
+	/* An IRS is architecturally allowed to have no cpus associated with it */
+	if (!of_property_present(node, "cpus") && !of_property_present(node, "arm,iaffids"))
+		return 0;
+
 	ncpus = of_count_phandle_with_args(node, "cpus", NULL);
 	if (ncpus < 0)
 		return -EINVAL;

-- 
2.53.0