PCI/MSI: Fix MSIs for generic hosts that use device-tree's "msi-map"
Since commit 9ec37efb8783 ("PCI/MSI: Make pci_host_common_probe() declare
its reliance on MSI domains"), platforms that rely on the "msi-map"
device-tree property don't get MSIs anymore.
On the Arm Fast Model for example [1], the host bridge doesn't have a
"msi-parent" property since it doesn't itself generate MSIs, and so doesn't
get a MSI domain. It has an "msi-map" property instead to describe MSI
controllers of child devices. As a result, due to the new msi_domain check
in pci_register_host_bridge(), the whole bus gets PCI_BUS_FLAGS_NO_MSI.
Check whether the root complex has an "msi-map" property before giving
up on MSIs.
[1] arch/arm64/boot/dts/arm/fvp-base-revc.dts
Fixes: 9ec37efb8783 ("PCI/MSI: Make pci_host_common_probe() declare its reliance on MSI domains")
Link: https://lore.kernel.org/r/20210510173129.750496-1-jean-philippe@linaro.org
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Marc Zyngier <maz@kernel.org>
diff --git a/drivers/pci/of.c b/drivers/pci/of.c
index da5b414d..85dcb70 100644
--- a/drivers/pci/of.c
+++ b/drivers/pci/of.c
@@ -103,6 +103,13 @@
#endif
}
+bool pci_host_of_has_msi_map(struct device *dev)
+{
+ if (dev && dev->of_node)
+ return of_get_property(dev->of_node, "msi-map", NULL);
+ return false;
+}
+
static inline int __of_pci_pci_compare(struct device_node *node,
unsigned int data)
{
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 3a62d09..2752046 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -925,7 +925,8 @@
device_enable_async_suspend(bus->bridge);
pci_set_bus_of_node(bus);
pci_set_bus_msi_domain(bus);
- if (bridge->msi_domain && !dev_get_msi_domain(&bus->dev))
+ if (bridge->msi_domain && !dev_get_msi_domain(&bus->dev) &&
+ !pci_host_of_has_msi_map(parent))
bus->bus_flags |= PCI_BUS_FLAGS_NO_MSI;
if (!parent)
diff --git a/include/linux/pci.h b/include/linux/pci.h
index c20211e..2430650 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -2344,6 +2344,7 @@
struct device_node;
struct irq_domain;
struct irq_domain *pci_host_bridge_of_msi_domain(struct pci_bus *bus);
+bool pci_host_of_has_msi_map(struct device *dev);
/* Arch may override this (weak) */
struct device_node *pcibios_get_phb_of_node(struct pci_bus *bus);
@@ -2351,6 +2352,7 @@
#else /* CONFIG_OF */
static inline struct irq_domain *
pci_host_bridge_of_msi_domain(struct pci_bus *bus) { return NULL; }
+static inline bool pci_host_of_has_msi_map(struct device *dev) { return false; }
#endif /* CONFIG_OF */
static inline struct device_node *
