1 files changed, 101 insertions, 0 deletions
diff --git a/drivers/pci/host-bridge.c b/drivers/pci/host-bridge.c
new file mode 100644
index 000000000..afa50b446
--- /dev/null
+++ b/drivers/pci/host-bridge.c
@@ -0,0 +1,101 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Host bridge related code
+ */
+
+#include <linux/kernel.h>
+#include <linux/pci.h>
+#include <linux/module.h>
+
+#include "pci.h"
+
+static struct pci_bus *find_pci_root_bus(struct pci_bus *bus)
+{
+	while (bus->parent)
+		bus = bus->parent;
+
+	return bus;
+}
+
+struct pci_host_bridge *pci_find_host_bridge(struct pci_bus *bus)
+{
+	struct pci_bus *root_bus = find_pci_root_bus(bus);
+
+	return to_pci_host_bridge(root_bus->bridge);
+}
+EXPORT_SYMBOL_GPL(pci_find_host_bridge);
+
+struct device *pci_get_host_bridge_device(struct pci_dev *dev)
+{
+	struct pci_bus *root_bus = find_pci_root_bus(dev->bus);
+	struct device *bridge = root_bus->bridge;
+
+	kobject_get(&bridge->kobj);
+	return bridge;
+}
+
+void  pci_put_host_bridge_device(struct device *dev)
+{
+	kobject_put(&dev->kobj);
+}
+
+void pci_set_host_bridge_release(struct pci_host_bridge *bridge,
+				 void (*release_fn)(struct pci_host_bridge *),
+				 void *release_data)
+{
+	bridge->release_fn = release_fn;
+	bridge->release_data = release_data;
+}
+EXPORT_SYMBOL_GPL(pci_set_host_bridge_release);
+
+void pcibios_resource_to_bus(struct pci_bus *bus, struct pci_bus_region *region,
+			     struct resource *res)
+{
+	struct pci_host_bridge *bridge = pci_find_host_bridge(bus);
+	struct resource_entry *window;
+	resource_size_t offset = 0;
+
+	resource_list_for_each_entry(window, &bridge->windows) {
+		if (resource_contains(window->res, res)) {
+			offset = window->offset;
+			break;
+		}
+	}
+
+	region->start = res->start - offset;
+	region->end = res->end - offset;
+}
+EXPORT_SYMBOL(pcibios_resource_to_bus);
+
+static bool region_contains(struct pci_bus_region *region1,
+			    struct pci_bus_region *region2)
+{
+	return region1->start <= region2->start && region1->end >= region2->end;
+}
+
+void pcibios_bus_to_resource(struct pci_bus *bus, struct resource *res,
+			     struct pci_bus_region *region)
+{
+	struct pci_host_bridge *bridge = pci_find_host_bridge(bus);
+	struct resource_entry *window;
+	resource_size_t offset = 0;
+
+	resource_list_for_each_entry(window, &bridge->windows) {
+		struct pci_bus_region bus_region;
+
+		if (resource_type(res) != resource_type(window->res))
+			continue;
+
+		bus_region.start = window->res->start - window->offset;
+		bus_region.end = window->res->end - window->offset;
+
+		if (region_contains(&bus_region, region)) {
+			offset = window->offset;
+			break;
+		}
+	}
+
+	res->start = region->start + offset;
+	res->end = region->end + offset;
+}
+EXPORT_SYMBOL(pcibios_bus_to_resource);