PCI: Add pci_scan_root_bus_msi()

Add a pci_scan_root_bus_msi() interface so an arch can specify the MSI
controller up front.  This removes the need for a pcibios callback to set
the MSI controller later.

This is not exported because I'd like to replace the variety of "scan root
bus" interfaces with a single, more extensible interface that can handle
the MSI controller, domain, pci_ops, resources, etc.  I hope this interface
is temporary.

[bhelgaas: changelog, split into separate patch]
Suggested-by: NRussell King <linux@arm.linux.org.uk>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NJingoo Han <jingoohan1@gmail.com>

drivers/pci/probe.c

@@ -2096,8 +2096,9 @@ void pci_bus_release_busn_res(struct pci_bus *b)
 			res, ret ? "can not be" : "is");
 }
 
-struct pci_bus *pci_scan_root_bus(struct device *parent, int bus,
-		struct pci_ops *ops, void *sysdata, struct list_head *resources)
+struct pci_bus *pci_scan_root_bus_msi(struct device *parent, int bus,
+		struct pci_ops *ops, void *sysdata,
+		struct list_head *resources, struct msi_controller *msi)
 {
 	struct resource_entry *window;
 	bool found = false;
@@ -2114,6 +2115,8 @@ struct pci_bus *pci_scan_root_bus(struct device *parent, int bus,
 	if (!b)
 		return NULL;
 
+	b->msi = msi;
+
 	if (!found) {
 		dev_info(&b->dev,
 		 "No busn resource found for root bus, will use [bus %02x-ff]\n",
@@ -2128,6 +2131,13 @@ struct pci_bus *pci_scan_root_bus(struct device *parent, int bus,
 
 	return b;
 }
+
+struct pci_bus *pci_scan_root_bus(struct device *parent, int bus,
+		struct pci_ops *ops, void *sysdata, struct list_head *resources)
+{
+	return pci_scan_root_bus_msi(parent, bus, ops, sysdata, resources,
+				     NULL);
+}
 EXPORT_SYMBOL(pci_scan_root_bus);
 
 struct pci_bus *pci_scan_bus(int bus, struct pci_ops *ops,

include/linux/pci.h

@@ -787,6 +787,10 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus,
 int pci_bus_insert_busn_res(struct pci_bus *b, int bus, int busmax);
 int pci_bus_update_busn_res_end(struct pci_bus *b, int busmax);
 void pci_bus_release_busn_res(struct pci_bus *b);
+struct pci_bus *pci_scan_root_bus_msi(struct device *parent, int bus,
+				      struct pci_ops *ops, void *sysdata,
+				      struct list_head *resources,
+				      struct msi_controller *msi);
 struct pci_bus *pci_scan_root_bus(struct device *parent, int bus,
 					     struct pci_ops *ops, void *sysdata,
 					     struct list_head *resources);