[RFC PATCH 08/16] PCI: Introduce pci_scan_host_bridge() and pci_host_info

[Yijing Wang <wangyijing@huawei.com>]

From: Yijing Wang <wangyijing0307@gmail.com>

Now pci_host_bridge has been ripped out from pci root
bus creation. Currently pci_scan_root_bus() lacks
scalability, so platform host drivers have no proper
way to configure pci_host_bridge. E.g we should assign
msi_controller to pci_host_bridge, add argument for
pci_scan_root_bus() is not a good idea, it has already
five, so introudce struct pci_host_info to make
pci scan interfaces more scalable. Because almost
all host drivers need to configure host resources,
so we put .init_res() in it first, and add other
hooks when need.

Signed-off-by: Yijing Wang <wangyijing@huawei.com>
---
 drivers/pci/host-bridge.c |   27 +++++++++-------
 drivers/pci/probe.c       |   73 ++++++++++++++++++++++++++++++++++++++++++--
 include/linux/pci.h       |   20 ++++++++++++-
 3 files changed, 103 insertions(+), 17 deletions(-)

diff --git a/drivers/pci/host-bridge.c b/drivers/pci/host-bridge.c
index e31604f..49b6c21 100644
--- a/drivers/pci/host-bridge.c
+++ b/drivers/pci/host-bridge.c
@@ -8,9 +8,6 @@
 
 #include "pci.h"
 
-LIST_HEAD(pci_host_bridge_list);
-DECLARE_RWSEM(pci_host_bridge_sem);
-
 static struct resource busn_resource = {
 	.name	= "PCI busn",
 	.start	= 0,
@@ -18,6 +15,9 @@ static struct resource busn_resource = {
 	.flags	= IORESOURCE_BUS,
 };
 
+LIST_HEAD(pci_host_bridge_list);
+DECLARE_RWSEM(pci_host_bridge_sem);
+
 static void pci_release_host_bridge_dev(struct device *dev)
 {
 	struct pci_host_bridge *bridge = to_pci_host_bridge(dev);
@@ -29,14 +29,12 @@ static void pci_release_host_bridge_dev(struct device *dev)
 }
 
 struct pci_host_bridge *pci_create_host_bridge(
-		struct device *parent, u32 db, 
-		struct pci_ops *ops, void *sysdata, 
-		struct list_head *resources)
+		struct device *parent, u32 db, struct pci_ops *ops, 
+		struct pci_host_info *info)
 {
 	int error;
 	struct pci_bus *b;
 	struct pci_host_bridge *host, *h;
-	struct pci_host_bridge_window *window, *n;
 
 	down_read(&pci_host_bridge_sem);
 	list_for_each_entry(h, &pci_host_bridge_list, list) {
@@ -53,7 +51,7 @@ struct pci_host_bridge *pci_create_host_bridge(
 	if (!host)
 		return NULL;
 
-	host->sysdata = sysdata;
+	host->sysdata = info->arg;
 	host->busnum = PCI_BUSNUM(db);
 	host->domain = PCI_DOMAIN(db);
 	host->ops = ops;
@@ -63,18 +61,23 @@ struct pci_host_bridge *pci_create_host_bridge(
 
 	/* this is hack, just for build, will be removed later*/
 	b = kzalloc(sizeof(*b), GFP_KERNEL);
-	b->sysdata = sysdata;
+	b->sysdata = host->sysdata;
 	pci_bus_assign_domain_nr(b, parent);
 	host->domain = pci_domain_nr(b);
+	kfree(b);
 
-	if (!resources) {
+	if (info->res_type = PCI_HOST_RES_DEFAULT) {
 		/* Use default IO/MEM/BUS resources*/
 		pci_add_resource(&host->windows, &ioport_resource);
 		pci_add_resource(&host->windows, &iomem_resource);
 		pci_add_resource(&host->windows, &busn_resource);
 	} else {
-		list_for_each_entry_safe(window, n, resources, list)
-			list_move_tail(&window->list, &host->windows);
+		if (!info->init_res || info->init_res(host, info)) {
+			pr_err("pci host %04x:%02x init resources fail\n",
+					host->domain, host->busnum);
+			kfree(host);
+			return NULL;
+		}
 	}
 
 	dev_set_name(&host->dev, "pci%04x:%02x", host->domain, 
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index d472da4..42158fd 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1863,6 +1863,21 @@ void __weak pcibios_remove_bus(struct pci_bus *bus)
 {
 }
 
+static int pci_default_init_res(struct pci_host_bridge *host,
+		struct pci_host_info *info)
+{
+	struct pci_host_bridge_window *window, *n;
+
+	if (info->res_type != PCI_HOST_RES_DEFAULT) 
+		list_for_each_entry_safe(window, n, info->resources,
+				list)
+			list_move_tail(&window->list, &host->windows);
+	else
+		info->res_type = PCI_HOST_RES_DEFAULT;
+
+	return 0;
+}
+
 struct pci_bus *__pci_create_root_bus(struct pci_host_bridge *bridge)
 {
 	int error;
@@ -1949,13 +1964,17 @@ err_out:
 	return NULL;
 }
 
-struct pci_bus *pci_create_root_bus(struct device *parent, u32 bus,
+struct pci_bus *pci_create_root_bus(struct device *parent, u32 db,
 		struct pci_ops *ops, void *sysdata, struct list_head *resources)
 {
 	struct pci_host_bridge *host;
+	struct pci_host_info info;
+	
+	info.arg= sysdata;
+	info.resources = resources;
+	info.init_res = pci_default_init_res;
 
-	host = pci_create_host_bridge(parent, bus, ops, 
-			sysdata ,resources);
+	host = pci_create_host_bridge(parent, db, ops, &info);
 	if (!host)
 		return NULL;
 
@@ -2038,8 +2057,13 @@ struct pci_bus *pci_scan_root_bus(struct device *parent, u32 db,
 	bool found = false;
 	struct pci_host_bridge *host;
 	int max;
+	struct pci_host_info info;
+	
+	info.arg = sysdata;
+	info.resources = resources;
+	info.init_res = pci_default_init_res;
 
-	host = pci_create_host_bridge(parent, db, ops, sysdata, resources);
+	host = pci_create_host_bridge(parent, db, ops, &info);
 	if (!host)
 		return NULL;
 
@@ -2070,6 +2094,47 @@ struct pci_bus *pci_scan_root_bus(struct device *parent, u32 db,
 }
 EXPORT_SYMBOL(pci_scan_root_bus);
 
+struct pci_host_bridge *pci_scan_host_bridge(
+		struct device *parent, u32 db, struct pci_ops *ops,
+		struct pci_host_info *info)
+{
+	struct pci_host_bridge_window *window;
+	bool found = false;
+	struct pci_host_bridge *host;
+	int max;
+
+	host = pci_create_host_bridge(parent, db, ops, info);
+	if (!host)
+		return NULL;
+
+	list_for_each_entry(window, &host->windows, list)
+		if (window->res->flags & IORESOURCE_BUS) {
+			found = true;
+			break;
+		}
+
+	host->bus = __pci_create_root_bus(host);
+	if (!host->bus) {
+		pci_free_host_bridge(host);
+		return NULL;
+	}
+
+	if (!found) {
+		dev_info(&host->bus->dev,
+		 "No busn resource found for root bus, will use [bus %02x-ff]\n",
+			host->busnum);
+		pci_bus_insert_busn_res(host->bus, host->busnum, 255);
+	}
+
+	max = pci_scan_child_bus(host->bus);
+	if (!found)
+		pci_bus_update_busn_res_end(host->bus, max);
+
+	return host;
+
+}
+EXPORT_SYMBOL(pci_scan_host_bridge);
+
 /**
  * pci_rescan_bus_bridge_resize - scan a PCI bus for devices.
  * @bridge: PCI bridge for the bus to scan
diff --git a/include/linux/pci.h b/include/linux/pci.h
index daa7f40..a51f5f5 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -412,6 +412,21 @@ struct pci_host_bridge {
 	void *release_data;
 };
 
+struct pci_host_info {
+	u8 res_type;
+	void *arg;
+	struct list_head *resources; /*just for build, will clean up later */
+	int (*init_res)(struct pci_host_bridge *host, 
+			struct pci_host_info *info);
+};
+
+static inline void init_pci_host_info(struct pci_host_info *info)
+{
+	memset(info, 0 , sizeof(*info));
+}
+
+#define PCI_HOST_RES_DEFAULT	0x2
+
 #define	to_pci_host_bridge(n) container_of(n, struct pci_host_bridge, dev)
 void pci_set_host_bridge_release(struct pci_host_bridge *bridge,
 		     void (*release_fn)(struct pci_host_bridge *),
@@ -420,7 +435,7 @@ void pci_set_host_bridge_release(struct pci_host_bridge *bridge,
 int pcibios_root_bridge_prepare(struct pci_host_bridge *bridge);
 struct pci_host_bridge *pci_create_host_bridge(
 		struct device *parent, u32 db, struct pci_ops *ops, 
-		void *sys, struct list_head *resources);
+		struct pci_host_info *info);
 /*
  * The first PCI_BRIDGE_RESOURCE_NUM PCI bus resources (those that correspond
  * to P2P or CardBus bridge windows) go in a table.  Additional ones (for
@@ -785,6 +800,9 @@ void pci_bus_release_busn_res(struct pci_bus *b);
 struct pci_bus *pci_scan_root_bus(struct device *parent, u32 bus,
 					     struct pci_ops *ops, void *sysdata,
 					     struct list_head *resources);
+struct pci_host_bridge *pci_scan_host_bridge(struct device *parent,
+		u32 db, struct pci_ops *ops,
+		struct pci_host_info *info);
 struct pci_bus *pci_add_new_bus(struct pci_bus *parent, struct pci_dev *dev,
 				int busnr);
 void pcie_update_link_speed(struct pci_bus *bus, u16 link_status);
-- 
1.7.1