ACPI: Add acpi_resource_consumer() to find device that claims a resource

Add acpi_resource_consumer().  This takes a struct resource and searches
the ACPI namespace for a device whose current resource settings (_CRS)
includes the resource.  It returns the device if it exists, or NULL if no
device uses the resource.

If more than one device uses the resource (this may happen in the case of
bridges), acpi_resource_consumer() returns the first one found by
acpi_get_devices() in its modified depth-first walk of the namespace.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index ddbeda6dbdc8..b00ad73c946d 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -419,6 +419,8 @@ static inline int acpi_dev_filter_resource_type_cb(struct acpi_resource *ares,
         return acpi_dev_filter_resource_type(ares, (unsigned long)arg);
 }
 
+struct acpi_device *acpi_resource_consumer(struct resource *res);
+
 int acpi_check_resource_conflict(const struct resource *res);
 
 int acpi_check_region(resource_size_t start, resource_size_t n,
@@ -762,6 +764,11 @@ static inline int acpi_reconfig_notifier_unregister(struct notifier_block *nb)
         return -EINVAL;
 }
 
+static inline struct acpi_device *acpi_resource_consumer(struct resource *res)
+{
+        return NULL;
+}
+
 #endif  /* !CONFIG_ACPI */
 
 #ifdef CONFIG_ACPI_HOTPLUG_IOAPIC