Thread (44 messages) 44 messages, 8 authors, 2025-10-20

Re: [PATCH v3 04/26] platform: Add firmware-agnostic irq and affinity retrieval interface

From: Jonathan Cameron <jonathan.cameron@huawei.com>
Date: 2025-10-09 17:03:56
Also in: linux-acpi, lkml

On Mon, 22 Sep 2025 09:28:11 +0100
Marc Zyngier [off-list ref] wrote:
Expand platform_get_irq_optional() to also return an affinity if
available, renaming it to platform_get_irq_affinity() in the
process.

platform_get_irq_optional() is preserved with its current semantics
by calling into the new helper with a NULL affinity pointer.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Maybe a breadcrumb of a comment for those of us who can't be bothered
to figure out why this needs the ifndef CONFIG_SPARC?

Otherwise a question on whether it's worth spinning a fwnode.h handler
to hide away the fwnode type in get_irq_affinity.
I think not given the complexity already there for the platform device
irq stuff, but thought I'd mention it.

Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
quoted hunk ↗ jump to hunk
---
 drivers/base/platform.c         | 60 +++++++++++++++++++++++++++------
 include/linux/platform_device.h |  2 ++
 2 files changed, 52 insertions(+), 10 deletions(-)
diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index 09450349cf323..3a058f63ef0d3 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -150,25 +150,37 @@ devm_platform_ioremap_resource_byname(struct platform_device *pdev,
 EXPORT_SYMBOL_GPL(devm_platform_ioremap_resource_byname);
 #endif /* CONFIG_HAS_IOMEM */
 
+static const struct cpumask *get_irq_affinity(struct platform_device *dev,
+					      unsigned int num)
+{
+	const struct cpumask *mask = NULL;
+#ifndef CONFIG_SPARC
+	struct fwnode_handle *fwnode = dev_fwnode(&dev->dev);
+
+	if (is_of_node(fwnode))
+		mask = of_irq_get_affinity(to_of_node(fwnode), num);
+	else if (is_acpi_device_node(fwnode))
+		mask = acpi_irq_get_affinity(ACPI_HANDLE_FWNODE(fwnode), num);
Not sure how useful it will be more generally, but maybe use fwnode.h and
appropriate callback rather than opencoding here?

Mind you the extra handling in existing platform_get_irq_optional()
for corner cases doesn't really fit with that model.
+#endif
+
+	return mask ?: cpu_possible_mask;
+}
  
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