export acpi_pci_root to find pci_bus correctly

We can simplify ACPI drivers if we can tell whether a handle is an ACPI PCI root or not.

Cc Bjorn Helgaas <[email protected]>

Signed-off-by Alex Chiang <[email protected]>

---

 drivers/acpi/pci_root.c |   17 ++---------------
 include/acpi/acpi_bus.h |   16 ++++++++++++++++
 2 files changed, 18 insertions(+), 15 deletions(-)

drivers/acpi/pci_root.c +2 -15

index 55b5b90..31b961c 100644
@@ -61,20 +61,6 @@ static struct acpi_driver acpi_pci_root_driver = {
 		},
 };
 
-struct acpi_pci_root {
-	struct list_head node;
-	struct acpi_device *device;
-	struct pci_bus *bus;
-	u16 segment;
-	u8 bus_nr;
-
-	u32 osc_support_set;	/* _OSC state of support bits */
-	u32 osc_control_set;	/* _OSC state of control bits */
-	u32 osc_control_qry;	/* the latest _OSC query result */
-
-	u32 osc_queried:1;	/* has _OSC control been queried? */
-};
-
 static LIST_HEAD(acpi_pci_roots);
 
 static struct acpi_pci_driver *sub_driver;

@@ -317,7 +303,7 @@ static acpi_status acpi_pci_osc_support(struct acpi_pci_root *root, u32 flags)
 	return status;
 }
 
-static struct acpi_pci_root *acpi_pci_find_root(acpi_handle handle)
+struct acpi_pci_root *acpi_pci_find_root(acpi_handle handle)
 {
 	struct acpi_pci_root *root;
 

@@ -327,6 +313,7 @@ static struct acpi_pci_root *acpi_pci_find_root(acpi_handle handle)
 	}
 	return NULL;
 }
+EXPORT_SYMBOL_GPL(acpi_pci_find_root);
 
 struct acpi_handle_node {
 	struct list_head node;

include/acpi/acpi_bus.h +16 -1

index c65e4ce..c3ace75 100644
@@ -369,10 +369,26 @@ int register_acpi_bus_type(struct acpi_bus_type *);
 int unregister_acpi_bus_type(struct acpi_bus_type *);
 struct device *acpi_get_physical_device(acpi_handle);
 
+struct acpi_pci_root {
+	struct list_head node;
+	struct acpi_device * device;
+	struct acpi_pci_id id;
+	struct pci_bus *bus;
+	u16 segment;
+	u8 bus_nr;
+
+	u32 osc_support_set;	/* _OSC state of support bits */
+	u32 osc_control_set;	/* _OSC state of control bits */
+	u32 osc_control_qry;	/* the latest _OSC query result */
+
+	u32 osc_queried:1;	/* has _OSC control been queried? */
+};
+
 /* helper */
 acpi_handle acpi_get_child(acpi_handle, acpi_integer);
 int acpi_is_root_bridge(acpi_handle);
 acpi_handle acpi_get_pci_rootbridge_handle(unsigned int, unsigned int);
+struct acpi_pci_root *acpi_pci_find_root(acpi_handle handle);
 #define DEVICE_ACPI_HANDLE(dev) ((acpi_handle)((dev)->archdata.acpi_handle))
 
 #ifdef CONFIG_PM_SLEEP
 
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We cannot simply call acpi_get_pci_dev() on any random ACPI handle and hope that it works, because a PCI root bridge may not have an associated struct pci_dev.

This is allowed per the PCI specification, and is referred to as a non-materialized bridge.

So, depending on the type of PCI bridge that the handle points to, use the appropriate interface to return the struct pci_bus correctly.

Signed-off-by Alex Chiang <[email protected]>

---

 drivers/pci/hotplug/acpiphp_glue.c |   28 +++++++++++++++++-----------
 1 files changed, 17 insertions(+), 11 deletions(-)

drivers/pci/hotplug/acpiphp_glue.c +17 -12

index 0cb0f83..2e5f259 100644
@@ -62,6 +62,22 @@ static void acpiphp_sanitize_bus(struct pci_bus *bus);
 static void acpiphp_set_hpp_values(acpi_handle handle, struct pci_bus *bus);
 static void handle_hotplug_event_func(acpi_handle handle, u32 type, void *context);
 
+static struct pci_bus *pci_bus_from_handle(acpi_handle handle)
+{
+	struct pci_bus *pbus;
+	struct acpi_pci_root *root;
+
+	root = acpi_pci_find_root(handle);
+	if (root)
+		pbus = root->bus;
+	else {
+		struct pci_dev *pdev = acpi_get_pci_dev(handle);
+		pbus = pdev->subordinate;
+		pci_dev_put(pdev);
+	}
+	return pbus;
+}
+
 /* callback routine to check for the existence of a pci dock device */
 static acpi_status
 is_pci_dock_device(acpi_handle handle, u32 lvl, void *context, void **rv)

@@ -1387,16 +1403,7 @@ static void acpiphp_sanitize_bus(struct pci_bus *bus)
 /* Program resources in newly inserted bridge */
 static int acpiphp_configure_bridge (acpi_handle handle)
 {
-	struct pci_dev *dev;
-	struct pci_bus *bus;
-
-	dev = acpi_get_pci_dev(handle);
-	if (!dev) {
-		err("cannot get PCI domain and bus number for bridge\n");
-		return -EINVAL;
-	}
-
-	bus = dev->bus;
+	struct pci_bus *bus = pci_bus_from_handle(handle);
 
 	pci_bus_size_bridges(bus);
 	pci_bus_assign_resources(bus);

@@ -1404,7 +1411,6 @@ static int acpiphp_configure_bridge (acpi_handle handle)
 	acpiphp_set_hpp_values(handle, bus);
 	pci_enable_bridges(bus);
 	acpiphp_configure_ioapics(handle);
-	pci_dev_put(dev);
 	return 0;
 }
 
 
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We cannot simply call acpi_get_pci_dev() on any random ACPI handle and hope that it works, because a PCI root bridge may not have an associated struct pci_dev.

This is allowed per the PCI specification, and is referred to as a non-materialized bridge.

So, depending on the type of PCI bridge that the handle points to, use the appropriate interface to return the struct pci_bus correctly.

Signed-off-by Alex Chiang <[email protected]>

---

Quoted 10 lines · On Thu, 23 Jul 2009 17:03:05 -0600 Alex Chiang <[email protected]> wrote:

We cannot simply call acpi_get_pci_dev() on any random ACPI handle and hope that it works, because a PCI root bridge may not have an associated struct pci_dev.

This is allowed per the PCI specification, and is referred to as a non-materialized bridge.

So, depending on the type of PCI bridge that the handle points to, use the appropriate interface to return the struct pci_bus correctly.

Quoted 2 lines

Signed-off-by Alex Chiang <[email protected]>

---

I put these in my linux-next branch, just because I'm really conservative about the current release.

If we hear of boxes in the wild getting bitten by the non-materialized bit, we can push this set back to stable.