[PATCH v6 12/30] PCI: Introduce pci_host_bridge_ops to support host specific operations

[Yijing Wang <wangyijing@huawei.com>]

Now we have weak functions like pcibios_root_bridge_prepare()
to setup pci host bridge, We could introduce pci_host_bridge_ops
which contain host bridge specific ops to setup pci_host_bridge.
Then host bridge driver could add pci_host_bridge_ops hooks
intead of weak function to setup pci_host_bridge.
This patch add following pci_host_bridge_ops hooks:

pci_host_bridge_ops {
	/* set root bus speed, some platform need this like powerpc */
	void (*set_root_bus_speed)(struct pci_host_bridge *host);
	/* setup pci_host_bridge before pci_host_bridge be added to driver core */
	int (*prepare)(struct pci_host_bridge *host);
	/* platform specific of scan hook to scan pci device */
	void (*scan_bus)(struct pci_host_bridge *);
}
We could easily extend it to support different host bridge
specific operations.

Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---
 drivers/pci/host-bridge.c |   12 ++++++++++--
 drivers/pci/pci.h         |    4 ++--
 drivers/pci/probe.c       |   17 +++++++++++------
 include/linux/pci.h       |    8 ++++++++
 4 files changed, 31 insertions(+), 10 deletions(-)

diff --git a/drivers/pci/host-bridge.c b/drivers/pci/host-bridge.c
index 3c34c49..bc1de59 100644
--- a/drivers/pci/host-bridge.c
+++ b/drivers/pci/host-bridge.c
@@ -23,8 +23,8 @@ static void pci_release_host_bridge_dev(struct device *dev)
 }
 
 struct pci_host_bridge *pci_create_host_bridge(
-		struct device *parent, u32 db,
-		struct list_head *resources, void *sysdata)
+		struct device *parent, u32 db, struct list_head *resources,
+		void *sysdata, struct pci_host_bridge_ops *ops)
 {
 	int error;
 	int bus = PCI_BUSNUM(db);
@@ -56,6 +56,7 @@ struct pci_host_bridge *pci_create_host_bridge(
 		}
 	mutex_unlock(&phb_mutex);
 
+	host->ops = ops;
 	host->dev.parent = parent;
 	INIT_LIST_HEAD(&host->windows);
 	host->dev.release = pci_release_host_bridge_dev;
@@ -63,6 +64,13 @@ struct pci_host_bridge *pci_create_host_bridge(
 	dev_set_name(&host->dev, "pci%04x:%02x", host->domain,
 			host->busnum);
 
+	if (host->ops && host->ops->prepare) {
+		error = host->ops->prepare(host);
+		if (error) {
+			kfree(host);
+			return NULL;
+		}
+	}
 	error = device_register(&host->dev);
 	if (error) {
 		put_device(&host->dev);
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 79a8894..a1dc9f2 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -324,8 +324,8 @@ static inline int pci_dev_specific_reset(struct pci_dev *dev, int probe)
 #endif
 
 struct pci_host_bridge *pci_create_host_bridge(
-		struct device *parent, u32 dombus,
-		struct list_head *resources, void *sysdata);
+		struct device *parent, u32 dombus, struct list_head *resources,
+		void *sysdata, struct pci_host_bridge_ops *ops);
 
 void pci_free_host_bridge(struct pci_host_bridge *host);
 #endif /* DRIVERS_PCI_H */
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index c8e074d..59d9be3 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1889,6 +1889,8 @@ static struct pci_bus *__pci_create_root_bus(
 
 	bridge->bus = b;
 	b->bridge = get_device(&bridge->dev);
+	if (bridge->ops && bridge->ops->set_root_bus_speed)
+		bridge->ops->set_root_bus_speed(bridge);
 	error = pcibios_root_bridge_prepare(bridge);
 	if (error)
 		goto err_out;
@@ -1954,7 +1956,7 @@ struct pci_bus *pci_create_root_bus(struct device *parent, u32 db,
 {
 	struct pci_host_bridge *host;
 
-	host = pci_create_host_bridge(parent, db, resources, sysdata);
+	host = pci_create_host_bridge(parent, db, resources, sysdata, NULL);
 	if (!host)
 		return NULL;
 
@@ -2051,10 +2053,13 @@ static struct pci_bus *__pci_scan_root_bus(
 		pci_bus_insert_busn_res(b, b->number, 255);
 	}
 
-	max = pci_scan_child_bus(b);
-
-	if (!found)
-		pci_bus_update_busn_res_end(b, max);
+	if (host->ops && host->ops->scan_bus) {
+		host->ops->scan_bus(host);
+	} else {
+		max = pci_scan_child_bus(b);
+		if (!found)
+			pci_bus_update_busn_res_end(b, max);
+	}
 
 	return b;
 }
@@ -2064,7 +2069,7 @@ struct pci_bus *pci_scan_root_bus(struct device *parent, u32 db,
 {
 	struct pci_host_bridge *host;
 
-	host = pci_create_host_bridge(parent, db, resources, sysdata);
+	host = pci_create_host_bridge(parent, db, resources, sysdata, NULL);
 	if (!host)
 		return NULL;
 
diff --git a/include/linux/pci.h b/include/linux/pci.h
index b621f5b..e9922b1 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -400,6 +400,13 @@ static inline int pci_channel_offline(struct pci_dev *pdev)
 	return (pdev->error_state != pci_channel_io_normal);
 }
 
+struct pci_host_bridge;
+struct pci_host_bridge_ops {
+	void (*set_root_bus_speed)(struct pci_host_bridge *host);
+	int (*prepare)(struct pci_host_bridge *host);
+	void (*scan_bus)(struct pci_host_bridge *);
+};
+
 struct pci_host_bridge {
 	u16	domain;
 	u16 busnum;
@@ -407,6 +414,7 @@ struct pci_host_bridge {
 	struct pci_bus *bus;		/* root bus */
 	struct list_head windows;	/* resource_entry */
 	struct list_head list;
+	struct pci_host_bridge_ops *ops;
 	void (*release_fn)(struct pci_host_bridge *);
 	void *release_data;
 };
-- 
1.7.1