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/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 @@ static int pci_register_host_bridge(struct pci_host_bridge *bridge)
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)
