in pci/pci-common.c [766:811]
static void __init pcibios_allocate_resources(int pass)
{
struct pci_dev *dev = NULL;
int idx, disabled;
u16 command;
struct resource *r;
for_each_pci_dev(dev) {
pci_read_config_word(dev, PCI_COMMAND, &command);
for (idx = 0; idx <= PCI_ROM_RESOURCE; idx++) {
r = &dev->resource[idx];
if (r->parent) /* Already allocated */
continue;
if (!r->flags || (r->flags & IORESOURCE_UNSET))
continue; /* Not assigned at all */
/* We only allocate ROMs on pass 1 just in case they
* have been screwed up by firmware
*/
if (idx == PCI_ROM_RESOURCE)
disabled = 1;
if (r->flags & IORESOURCE_IO)
disabled = !(command & PCI_COMMAND_IO);
else
disabled = !(command & PCI_COMMAND_MEMORY);
if (pass == disabled)
alloc_resource(dev, idx);
}
if (pass)
continue;
r = &dev->resource[PCI_ROM_RESOURCE];
if (r->flags) {
/* Turn the ROM off, leave the resource region,
* but keep it unregistered.
*/
u32 reg;
pci_read_config_dword(dev, dev->rom_base_reg, ®);
if (reg & PCI_ROM_ADDRESS_ENABLE) {
pr_debug("PCI: Switching off ROM of %s\n",
pci_name(dev));
r->flags &= ~IORESOURCE_ROM_ENABLE;
pci_write_config_dword(dev, dev->rom_base_reg,
reg & ~PCI_ROM_ADDRESS_ENABLE);
}
}
}
}