xref: /openbmc/linux/drivers/pci/host-bridge.c (revision 483eb062)
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 static bool resource_contains(struct resource *res1, struct resource *res2)
36 {
37 	return res1->start <= res2->start && res1->end >= res2->end;
38 }
39 
40 void pcibios_resource_to_bus(struct pci_bus *bus, struct pci_bus_region *region,
41 			     struct resource *res)
42 {
43 	struct pci_host_bridge *bridge = find_pci_host_bridge(bus);
44 	struct pci_host_bridge_window *window;
45 	resource_size_t offset = 0;
46 
47 	list_for_each_entry(window, &bridge->windows, list) {
48 		if (resource_type(res) != resource_type(window->res))
49 			continue;
50 
51 		if (resource_contains(window->res, res)) {
52 			offset = window->offset;
53 			break;
54 		}
55 	}
56 
57 	region->start = res->start - offset;
58 	region->end = res->end - offset;
59 }
60 EXPORT_SYMBOL(pcibios_resource_to_bus);
61 
62 static bool region_contains(struct pci_bus_region *region1,
63 			    struct pci_bus_region *region2)
64 {
65 	return region1->start <= region2->start && region1->end >= region2->end;
66 }
67 
68 void pcibios_bus_to_resource(struct pci_bus *bus, struct resource *res,
69 			     struct pci_bus_region *region)
70 {
71 	struct pci_host_bridge *bridge = find_pci_host_bridge(bus);
72 	struct pci_host_bridge_window *window;
73 	resource_size_t offset = 0;
74 
75 	list_for_each_entry(window, &bridge->windows, list) {
76 		struct pci_bus_region bus_region;
77 
78 		if (resource_type(res) != resource_type(window->res))
79 			continue;
80 
81 		bus_region.start = window->res->start - window->offset;
82 		bus_region.end = window->res->end - window->offset;
83 
84 		if (region_contains(&bus_region, region)) {
85 			offset = window->offset;
86 			break;
87 		}
88 	}
89 
90 	res->start = region->start + offset;
91 	res->end = region->end + offset;
92 }
93 EXPORT_SYMBOL(pcibios_bus_to_resource);
94