Re: [PATCH v2 4/7] PCI/MSI: Make the pci_msi_map_rid_ctlr_node() interface firmware agnostic

Bjorn Helgaas
2026-01-05T17:35:35Z

On Thu, Dec 18, 2025 at 11:14:30AM +0100, Lorenzo Pieralisi wrote:
> 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 <tglx@linutronix.de>
> Cc: Bjorn Helgaas <bhelgaas@google.com>
> Cc: Marc Zyngier <maz@kernel.org>

Acked-by: Bjorn Helgaas <bhelgaas@google.com>

I assume this series will be merged via some non-PCI tree. Let me
know if you need anything else.

> ---
> drivers/irqchip/irq-gic-its-msi-parent.c | 8 ++++----
> drivers/pci/msi/irqdomain.c | 22 +++++++++++++++++-----
> include/linux/msi.h | 3 ++-
> 3 files changed, 23 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/irqchip/irq-gic-its-msi-parent.c b/drivers/irqchip/irq-gic-its-msi-parent.c
> index 12f45228c867..4d1ad1ee005d 100644
> --- a/drivers/irqchip/irq-gic-its-msi-parent.c
> +++ b/drivers/irqchip/irq-gic-its-msi-parent.c
> @@ -104,7 +104,7 @@ static int its_pci_msi_prepare(struct irq_domain *domain, struct device *dev,
> static int its_v5_pci_msi_prepare(struct irq_domain *domain, struct device *dev,
> int nvec, msi_alloc_info_t *info)
> {
> - struct device_node *msi_node = NULL;
> + struct fwnode_handle *msi_node = NULL;
> struct msi_domain_info *msi_info;
> struct pci_dev *pdev;
> phys_addr_t pa;
> @@ -116,15 +116,15 @@ static int its_v5_pci_msi_prepare(struct irq_domain *domain, struct device *dev,
>
> pdev = to_pci_dev(dev);
>
> - rid = pci_msi_map_rid_ctlr_node(pdev, &msi_node);
> + rid = pci_msi_map_rid_ctlr_node(domain->parent, pdev, &msi_node);
> if (!msi_node)
> return -ENODEV;
>
> - ret = its_translate_frame_address(msi_node, &pa);
> + ret = its_translate_frame_address(to_of_node(msi_node), &pa);
> if (ret)
> return -ENODEV;
>
> - of_node_put(msi_node);
> + fwnode_handle_put(msi_node);
>
> /* ITS specific DeviceID */
> info->scratchpad[0].ul = rid;
> 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) {
> + struct device_node *msi_ctlr_node = NULL;
> +
> + rid = of_msi_xlate(&pdev->dev, &msi_ctlr_node, rid);
> + if (msi_ctlr_node)
> + *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);
>
> --
> 2.50.1
>