[PATCH v4 02/26] ACPI: irq: Add IRQ affinity reporting interface

Marc Zyngier
2025-10-20T12:30:10Z

Plug the irq_populate_fwspec_info() helper into the ACPI layer
to offer an IRQ affinity reporting function. This is currently
only supported for the CONFIG_ACPI_GENERIC_GSI configurations,
but could later be extended to legacy architectures if necessary.

Acked-by: Rafael J. Wysocki (Intel) <rafael@kernel.org>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Tested-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
drivers/acpi/irq.c | 19 +++++++++++++++++++
include/linux/acpi.h | 7 +++++++
2 files changed, 26 insertions(+)

diff --git a/drivers/acpi/irq.c b/drivers/acpi/irq.c
index 76a856c32c4d0..d1595156c86a4 100644
--- a/drivers/acpi/irq.c
+++ b/drivers/acpi/irq.c
@@ -300,6 +300,25 @@ int acpi_irq_get(acpi_handle handle, unsigned int index, struct resource *res)
}
EXPORT_SYMBOL_GPL(acpi_irq_get);

+const struct cpumask *acpi_irq_get_affinity(acpi_handle handle,
+ unsigned int index)
+{
+ struct irq_fwspec_info info;
+ struct irq_fwspec fwspec;
+ unsigned long flags;
+
+ if (acpi_irq_parse_one(handle, index, &fwspec, &flags))
+ return NULL;
+
+ if (irq_populate_fwspec_info(&fwspec, &info))
+ return NULL;
+
+ if (!(info.flags & IRQ_FWSPEC_INFO_AFFINITY_VALID))
+ return NULL;
+
+ return info.affinity;
+}
+
/**
* acpi_set_irq_model - Setup the GSI irqdomain information
* @model: the value assigned to acpi_irq_model
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 5ff5d99f6ead5..607db773b6721 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -1509,12 +1509,19 @@ static inline int acpi_parse_spcr(bool enable_earlycon, bool enable_console)

#if IS_ENABLED(CONFIG_ACPI_GENERIC_GSI)
int acpi_irq_get(acpi_handle handle, unsigned int index, struct resource *res);
+const struct cpumask *acpi_irq_get_affinity(acpi_handle handle,
+ unsigned int index);
#else
static inline
int acpi_irq_get(acpi_handle handle, unsigned int index, struct resource *res)
{
return -EINVAL;
}
+static inline const struct cpumask *acpi_irq_get_affinity(acpi_handle handle,
+ unsigned int index)
+{
+ return NULL;
+}
#endif

#ifdef CONFIG_ACPI_LPIT
--
2.47.3