xref: /openbmc/linux/drivers/pci/host-bridge.c (revision afb46f79)
1 /*
2  * host bridge related code
3  */
4 
5 #include <linux/kernel.h>
6 #include <linux/init.h>
7 #include <linux/pci.h>
8 #include <linux/module.h>
9 
10 #include "pci.h"
11 
12 static struct pci_bus *find_pci_root_bus(struct pci_bus *bus)
13 {
14 	while (bus->parent)
15 		bus = bus->parent;
16 
17 	return bus;
18 }
19 
20 static struct pci_host_bridge *find_pci_host_bridge(struct pci_bus *bus)
21 {
22 	struct pci_bus *root_bus = find_pci_root_bus(bus);
23 
24 	return to_pci_host_bridge(root_bus->bridge);
25 }
26 
27 void pci_set_host_bridge_release(struct pci_host_bridge *bridge,
28 				 void (*release_fn)(struct pci_host_bridge *),
29 				 void *release_data)
30 {
31 	bridge->release_fn = release_fn;
32 	bridge->release_data = release_data;
33 }
34 
35 void pcibios_resource_to_bus(struct pci_bus *bus, struct pci_bus_region *region,
36 			     struct resource *res)
37 {
38 	struct pci_host_bridge *bridge = find_pci_host_bridge(bus);
39 	struct pci_host_bridge_window *window;
40 	resource_size_t offset = 0;
41 
42 	list_for_each_entry(window, &bridge->windows, list) {
43 		if (resource_contains(window->res, res)) {
44 			offset = window->offset;
45 			break;
46 		}
47 	}
48 
49 	region->start = res->start - offset;
50 	region->end = res->end - offset;
51 }
52 EXPORT_SYMBOL(pcibios_resource_to_bus);
53 
54 static bool region_contains(struct pci_bus_region *region1,
55 			    struct pci_bus_region *region2)
56 {
57 	return region1->start <= region2->start && region1->end >= region2->end;
58 }
59 
60 void pcibios_bus_to_resource(struct pci_bus *bus, struct resource *res,
61 			     struct pci_bus_region *region)
62 {
63 	struct pci_host_bridge *bridge = find_pci_host_bridge(bus);
64 	struct pci_host_bridge_window *window;
65 	resource_size_t offset = 0;
66 
67 	list_for_each_entry(window, &bridge->windows, list) {
68 		struct pci_bus_region bus_region;
69 
70 		if (resource_type(res) != resource_type(window->res))
71 			continue;
72 
73 		bus_region.start = window->res->start - window->offset;
74 		bus_region.end = window->res->end - window->offset;
75 
76 		if (region_contains(&bus_region, region)) {
77 			offset = window->offset;
78 			break;
79 		}
80 	}
81 
82 	res->start = region->start + offset;
83 	res->end = region->end + offset;
84 }
85 EXPORT_SYMBOL(pcibios_bus_to_resource);
86