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

Yijing Wang
2014-11-17T09:43:45Z

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