On Mon, Jan 05, 2026 at 12:21:14PM +0000, Jonathan Cameron wrote:

On Thu, 18 Dec 2025 11:14:30 +0100
Lorenzo Pieralisi [off-list ref] wrote:

quoted

To support booting with OF and ACPI seamlessly, GIC ITS parent code
requires the PCI/MSI irqdomain layer to implement a function to retrieve
an MSI controller fwnode and map an RID in a firmware agnostic way
(ie pci_msi_map_rid_ctlr_node()).

Convert pci_msi_map_rid_ctlr_node() to an OF agnostic interface
(fwnode_handle based) and update the GIC ITS MSI parent code to reflect
the pci_msi_map_rid_ctlr_node() change.

Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Cc: Thomas Gleixner <redacted>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Marc Zyngier <maz@kernel.org>

Hi Lorenzo,

A few minor comments inline.  All in the 'up to you' category.

Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>

quoted

---

quoted

diff --git a/drivers/pci/msi/irqdomain.c b/drivers/pci/msi/irqdomain.c
index a329060287b5..3136341e802c 100644
--- a/drivers/pci/msi/irqdomain.c
+++ b/drivers/pci/msi/irqdomain.c

@@ -376,23 +376,35 @@ u32 pci_msi_domain_get_msi_rid(struct irq_domain *domain, struct pci_dev *pdev)
 }
 
 /**
- * pci_msi_map_rid_ctlr_node - Get the MSI controller node and MSI requester id (RID)
+ * pci_msi_map_rid_ctlr_node - Get the MSI controller fwnode_handle and MSI requester id (RID)
+ * @domain:	The interrupt domain
  * @pdev:	The PCI device
- * @node:	Pointer to store the MSI controller device node
+ * @node:	Pointer to store the MSI controller fwnode_handle
  *
- * Use the firmware data to find the MSI controller node for @pdev.
+ * Use the firmware data to find the MSI controller fwnode_handle for @pdev.
  * If found map the RID and initialize @node with it. @node value must
  * be set to NULL on entry.
  *
  * Returns: The RID.
  */
-u32 pci_msi_map_rid_ctlr_node(struct pci_dev *pdev, struct device_node **node)
+u32 pci_msi_map_rid_ctlr_node(struct irq_domain *domain, struct pci_dev *pdev,
+			      struct fwnode_handle **node)
 {
+	struct device_node *of_node;
 	u32 rid = pci_dev_id(pdev);
 
 	pci_for_each_dma_alias(pdev, get_msi_id_cb, &rid);
 
-	return of_msi_xlate(&pdev->dev, node, rid);
+	of_node = irq_domain_get_of_node(domain);
+	if (of_node) {

I haven't read on but my assumption is of_node is never used for anything else.
I'd make that explicit by not having the local variable.
	if (irq_domain_get_of_node(domain))

Might even be worth a comment to say this is just checking of is in use for the
domain in general?

Yes, I thought an explicit variable would make it clearer, don't know,
not a big deal either way I believe.

quoted

+		struct device_node *msi_ctlr_node = NULL;
+
+		rid = of_msi_xlate(&pdev->dev, &msi_ctlr_node, rid);
+		if (msi_ctlr_node)

Do you need the protection? Ultimately that depends on whether
setting *node = NULL on failure to match is a problem.
It's a bit subtle, but if your new code matches behavior of old code
then *node was always NULL at entry to this function so setting it
to NULL again (which is what happens if ms_ctrl_node == NULL) should
be fine.

Maybe it's all a bit subtle though so perhaps the check is worth having.

As above, I thought that to help understand what the function does
assigning only if !NULL would help, you are right though.

Thanks,
Lorenzo

quoted

+			*node = of_fwnode_handle(msi_ctlr_node);
+	}
+
+	return rid;
 }
 
 /**

diff --git a/include/linux/msi.h b/include/linux/msi.h
index 8003e3218c46..8ddb05d5c96a 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h

@@ -702,7 +702,8 @@ void __pci_write_msi_msg(struct msi_desc *entry, struct msi_msg *msg);
 void pci_msi_mask_irq(struct irq_data *data);
 void pci_msi_unmask_irq(struct irq_data *data);
 u32 pci_msi_domain_get_msi_rid(struct irq_domain *domain, struct pci_dev *pdev);
-u32 pci_msi_map_rid_ctlr_node(struct pci_dev *pdev, struct device_node **node);
+u32 pci_msi_map_rid_ctlr_node(struct irq_domain *domain, struct pci_dev *pdev,
+			      struct fwnode_handle **node);
 struct irq_domain *pci_msi_get_device_domain(struct pci_dev *pdev);
 void pci_msix_prepare_desc(struct irq_domain *domain, msi_alloc_info_t *arg,
 			   struct msi_desc *desc);