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Subject[PATCH v9 07/30] PCI: Add default bus resource in pci_host_bridge
Date
If there is no busn resource provided for pci_scan_root_bus(),
we would insert a default bus resource (root_bus_number, 255)
in root bus, and update the max bus number we found after
pci_scan_child_bus(). We also need to hold the default bus
resource in pci_host_bridge, then we could identify whether
the new pci host bridge conflict with existing one.

Signed-off-by: Yijing Wang <wangyijing@huawei.com>
---
drivers/pci/host-bridge.c | 20 ++++++++++++++++++++
drivers/pci/probe.c | 26 ++++++++++----------------
include/linux/pci.h | 2 ++
3 files changed, 32 insertions(+), 16 deletions(-)

diff --git a/drivers/pci/host-bridge.c b/drivers/pci/host-bridge.c
index 7d52a0a..ecc1a7c 100644
--- a/drivers/pci/host-bridge.c
+++ b/drivers/pci/host-bridge.c
@@ -19,6 +19,25 @@ static void pci_release_host_bridge_dev(struct device *dev)
kfree(bridge);
}

+static void pci_host_update_busn_res(
+ struct pci_host_bridge *host, int bus,
+ struct list_head *resources)
+{
+ struct resource_entry *window;
+
+ resource_list_for_each_entry(window, resources)
+ if (window->res->flags & IORESOURCE_BUS)
+ return;
+
+ pr_info(
+ "No busn resource found for pci%04x:%02x, will use [bus %02x-ff]\n",
+ host->domain, bus, bus);
+ host->busn_res.flags = IORESOURCE_BUS;
+ host->busn_res.start = bus;
+ host->busn_res.end = 255;
+ pci_add_resource(resources, &host->busn_res);
+}
+
struct pci_host_bridge *pci_create_host_bridge(
struct device *parent, int domain, int bus,
struct list_head *resources)
@@ -33,6 +52,7 @@ struct pci_host_bridge *pci_create_host_bridge(

host->dev.parent = parent;
INIT_LIST_HEAD(&host->windows);
+ pci_host_update_busn_res(host, bus, resources);
resource_list_for_each_entry_safe(window, n, resources)
list_move_tail(&window->node, &host->windows);
/*
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 9bc4784..d5a12d9 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2022,6 +2022,12 @@ int pci_bus_update_busn_res_end(struct pci_bus *b, int bus_max)
return ret;
}

+static void pci_host_update_busn_res_end(
+ struct pci_host_bridge *host, int max)
+{
+ host->busn_res.end = max;
+}
+
void pci_bus_release_busn_res(struct pci_bus *b)
{
struct resource *res = &b->busn_res;
@@ -2040,32 +2046,20 @@ static struct pci_bus *__pci_scan_root_bus(int bus,
struct pci_host_bridge *host, struct pci_ops *ops,
void *sysdata)
{
- struct resource_entry *window;
- bool found = false;
struct pci_bus *b;
int max;

- resource_list_for_each_entry(window, &host->windows)
- if (window->res->flags & IORESOURCE_BUS) {
- found = true;
- break;
- }
-
b = __pci_create_root_bus(bus, host, ops, sysdata);
if (!b)
return NULL;

- if (!found) {
- dev_info(&b->dev,
- "No busn resource found for root bus, will use [bus %02x-ff]\n",
- bus);
- pci_bus_insert_busn_res(b, bus, 255);
- }
-
max = pci_scan_child_bus(b);

- if (!found)
+ /* If default busn resource used, update the max bus number */
+ if (host->busn_res.flags & IORESOURCE_BUS) {
+ pci_host_update_busn_res_end(host, max);
pci_bus_update_busn_res_end(b, max);
+ }

return b;
}
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 1542df8..f189dfb 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -404,6 +404,8 @@ struct pci_host_bridge {
int domain;
struct device dev;
struct pci_bus *bus; /* root bus */
+ /* we use default bus resource if no bus resource provided */
+ struct resource busn_res;
struct list_head windows; /* resource_entry */
void (*release_fn)(struct pci_host_bridge *);
void *release_data;
--
1.7.1


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