/*
* Handle resources of PCI devices. If the world were perfect, we could
* just allocate all the resource regions and do nothing more. It isn't.
* On the other hand, we cannot just re-allocate all devices, as it would
* require us to know lots of host bridge internals. So we attempt to
* keep as much of the original configuration as possible, but tweak it
* when it's found to be wrong.
*
* Known BIOS problems we have to work around:
* - I/O or memory regions not configured
* - regions configured, but not enabled in the command register
* - bogus I/O addresses above 64K used
* - expansion ROMs left enabled (this may sound harmless, but given
* the fact the PCI specs explicitly allow address decoders to be
* shared between expansion ROMs and other resource regions, it's
* at least dangerous)
*
* Our solution:
* (1) Allocate resources for all buses behind PCI-to-PCI bridges.
* This gives us fixed barriers on where we can allocate.
* (2) Allocate resources for all enabled devices. If there is
* a collision, just mark the resource as unallocated. Also
* disable expansion ROMs during this step.
* (3) Try to allocate resources for disabled devices. If the
* resources were assigned correctly, everything goes well,
* if they weren't, they won't disturb allocation of other
* resources.
* (4) Assign new addresses to resources which were either
* not configured at all or misconfigured. If explicitly
* requested by the user, configure expansion ROM address
* as well.
*/
static void __init pcibios_allocate_bus_resources(struct list_head *bus_list)
{
struct pci_bus *bus;
struct pci_dev *dev;
int idx;
struct resource *r;
/* Depth-First Search on bus tree */
list_for_each_entry(bus, bus_list, node) {
dev = bus->self;
if (dev) {
for (idx = PCI_BRIDGE_RESOURCES;
idx < PCI_NUM_RESOURCES;
idx++) {
r = &dev->resource[idx];
if (!r->flags)
continue;
if (!r->start ||
pci_claim_bridge_resource(dev, idx) < 0) {
printk(KERN_ERR "PCI:"
" Cannot allocate resource"
" region %d of bridge %s\n",
idx, pci_name(dev));
/* Something is wrong with the region.
* Invalidate the resource to prevent
* child resource allocations in this
* range. */
r->start = r->end = 0;
r->flags = 0;
}
}
}
pcibios_allocate_bus_resources(&bus->children);
}
static void pcibios_fixup_bridge_resources(struct pci_dev *dev)
{
int idx;
if (!dev->bus)
return;
for (idx = PCI_BRIDGE_RESOURCES; idx < PCI_NUM_RESOURCES; idx++) {
struct resource *r = &dev->resource[idx];
if (!r->flags || r->parent || !r->start)
continue;
pci_claim_bridge_resource(dev, idx);
}
}
