So far, we've always considered that for a given PCI device, its
MSI controller was either set by the architecture-specific
pcibios hook, or simply inherited from the host bridge.
This doesn't cover things like firmware-defined topologies like
msi-map (DT) or IORT (ACPI), which can provide information about
which MSI controller to use on a per-device basis.
This patch adds the necessary hook into the MSI code to allow this
feature, and provides the msi-map functionnality as a first
implementation.
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
---
drivers/pci/msi.c | 17 +++++++++++++++++
drivers/pci/probe.c | 8 ++++++++
include/linux/msi.h | 6 ++++++
3 files changed, 31 insertions(+)
diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 81a2798..3daff31 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -1357,4 +1357,21 @@ u32 pci_msi_domain_get_msi_rid(struct irq_domain *domain, struct pci_dev *pdev)
return rid;
}
+
+/**
+ * pci_msi_get_device_domain - Get the MSI domain for a given PCI device
+ * @pdev: The PCI device
+ *
+ * Use the firmware data to find a device-specific MSI domain
+ * (i.e. not one that is ste as a default).
+ *
+ * Returns: The coresponding MSI domain or NULL if none has been found.
+ */
+struct irq_domain *pci_msi_get_device_domain(struct pci_dev *pdev)
+{
+ u32 rid = 0;
+
+ pci_for_each_dma_alias(pdev, get_msi_id_cb, &rid);
+ return of_msi_map_get_device_domain(&pdev->dev, rid);
+}
#endif /* CONFIG_PCI_MSI_IRQ_DOMAIN */
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 7c333f8..f14a970 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1639,6 +1639,14 @@ static struct irq_domain *pci_dev_msi_domain(struct pci_dev *dev)
if (d)
return d;
+ /*
+ * Let's see if we have a firmware interface able to provide
+ * the domain.
+ */
+ d = pci_msi_get_device_domain(dev);
+ if (d)
+ return d;
+
return NULL;
}
diff --git a/include/linux/msi.h b/include/linux/msi.h
index 56e3b76..375be7c 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -294,6 +294,12 @@ irq_hw_number_t pci_msi_domain_calc_hwirq(struct pci_dev *dev,
int pci_msi_domain_check_cap(struct irq_domain *domain,
struct msi_domain_info *info, struct device *dev);
u32 pci_msi_domain_get_msi_rid(struct irq_domain *domain, struct pci_dev *pdev);
+struct irq_domain *pci_msi_get_device_domain(struct pci_dev *pdev);
+#else
+static inline struct irq_domain *pci_msi_get_device_domain(struct pci_dev *pdev)
+{
+ return NULL;
+}
#endif /* CONFIG_PCI_MSI_IRQ_DOMAIN */
#endif /* LINUX_MSI_H */
--
2.1.4
--
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