[PATCH v6 27/31] irqchip/msi-lib: Add IRQ_DOMAIN_FLAG_FWNODE_PARENT handling

[Lorenzo Pieralisi <lpieralisi@kernel.org>]

In some irqchip implementations the fwnode representing the IRQdomain
and the MSI controller fwnode do not match; in particular the IRQdomain
fwnode is the MSI controller fwnode parent.

To support selecting such IRQ domains, add a flag in core IRQ domain
code that explicitly tells the MSI lib to use the parent fwnode while
carrying out IRQ domain selection.

Update the msi-lib select callback with the resulting logic.

Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Marc Zyngier <maz@kernel.org>
---
 drivers/irqchip/irq-msi-lib.c | 5 ++++-
 include/linux/irqdomain.h     | 3 +++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/irqchip/irq-msi-lib.c b/drivers/irqchip/irq-msi-lib.c
index 246c30205af4..454c7f16dd4d 100644
--- a/drivers/irqchip/irq-msi-lib.c
+++ b/drivers/irqchip/irq-msi-lib.c
@@ -133,11 +133,14 @@ int msi_lib_irq_domain_select(struct irq_domain *d, struct irq_fwspec *fwspec,
 {
 	const struct msi_parent_ops *ops = d->msi_parent_ops;
 	u32 busmask = BIT(bus_token);
+	struct fwnode_handle *fwh;
 
 	if (!ops)
 		return 0;
 
-	if (fwspec->fwnode != d->fwnode || fwspec->param_count != 0)
+	fwh = d->flags & IRQ_DOMAIN_FLAG_FWNODE_PARENT ? fwnode_get_parent(fwspec->fwnode)
+						       : fwspec->fwnode;
+	if (fwh != d->fwnode || fwspec->param_count != 0)
 		return 0;
 
 	/* Handle pure domain searches */
diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h
index 7387d183029b..25c7cbeed393 100644
--- a/include/linux/irqdomain.h
+++ b/include/linux/irqdomain.h
@@ -212,6 +212,9 @@ enum {
 	/* Address and data pair is mutable when irq_set_affinity() */
 	IRQ_DOMAIN_FLAG_MSI_IMMUTABLE	= (1 << 11),
 
+	/* IRQ domain requires parent fwnode matching */
+	IRQ_DOMAIN_FLAG_FWNODE_PARENT	= (1 << 12),
+
 	/*
 	 * Flags starting from IRQ_DOMAIN_FLAG_NONCORE are reserved
 	 * for implementation specific purposes and ignored by the

-- 
2.48.0