In order to be able to populate the device msi_domain field,
add the necesary hooks to propagate the PHB msi_domain across
secondary busses to devices.

So far, nobody populates the initial msi_domain.

Signed-off-by: Marc Zyngier <redacted>
---
 drivers/pci/probe.c | 24 ++++++++++++++++++++++++
 include/linux/pci.h |  1 +
 2 files changed, 25 insertions(+)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index c8ca98c..d1009a2 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c

@@ -670,6 +670,20 @@ static void pci_set_bus_speed(struct pci_bus *bus)
 	}
 }
 
+void __weak pcibios_set_phb_msi_domain(struct pci_bus *bus)
+{
+}
+
+static void pci_set_bus_msi_domain(struct pci_bus *bus)
+{
+	struct pci_dev *bridge = bus->self;
+
+	if (!bridge)
+		pcibios_set_phb_msi_domain(bus);
+	else
+		dev_set_msi_domain(&bus->dev, dev_get_msi_domain(&bridge->dev));
+}
+
 static struct pci_bus *pci_alloc_child_bus(struct pci_bus *parent,
 					   struct pci_dev *bridge, int busnr)
 {

@@ -723,6 +737,7 @@ static struct pci_bus *pci_alloc_child_bus(struct pci_bus *parent,
 	bridge->subordinate = child;
 
 add_dev:
+	pci_set_bus_msi_domain(child);
 	ret = device_register(&child->dev);
 	WARN_ON(ret < 0);
 

@@ -1517,6 +1532,11 @@ static void pci_init_capabilities(struct pci_dev *dev)
 	pci_enable_acs(dev);
 }
 
+static void pci_set_msi_domain(struct pci_dev *dev)
+{
+	dev_set_msi_domain(&dev->dev, dev_get_msi_domain(&dev->bus->dev));
+}
+

 void pci_device_add(struct pci_dev *dev, struct pci_bus *bus)
 {
 	int ret;

@@ -1546,6 +1566,9 @@ void pci_device_add(struct pci_dev *dev, struct pci_bus *bus)
 	/* Initialize various capabilities */
 	pci_init_capabilities(dev);
 
+	/* Setup MSI irq domain */
+	pci_set_msi_domain(dev);
+
 	/*
 	 * Add the device to our list of discovered devices
 	 * and the bus list for fixup functions, etc.

@@ -1947,6 +1970,7 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus,
 	b->bridge = get_device(&bridge->dev);
 	device_enable_async_suspend(b->bridge);
 	pci_set_bus_of_node(b);
+	pci_set_bus_msi_domain(b);
 
 	if (!parent)
 		set_dev_node(b->bridge, pcibus_to_node(b));

diff --git a/include/linux/pci.h b/include/linux/pci.h
index a523cee..3266764 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h

@@ -1637,6 +1637,7 @@ int pcibios_set_pcie_reset_state(struct pci_dev *dev,
 int pcibios_add_device(struct pci_dev *dev);
 void pcibios_release_device(struct pci_dev *dev);
 void pcibios_penalize_isa_irq(int irq, int active);
+void pcibios_set_phb_msi_domain(struct pci_bus *bus);
 
 #ifdef CONFIG_HIBERNATE_CALLBACKS
 extern struct dev_pm_ops pcibios_pm_ops;