1 files changed, 70 insertions, 1 deletions

diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
index 2538030954d8..da5a3855a0c4 100644
--- a/arch/powerpc/kernel/pci-common.c
+++ b/arch/powerpc/kernel/pci-common.c
@@ -16,7 +16,7 @@
  * 2 of the License, or (at your option) any later version.
  */
 
-#undef DEBUG
+#define DEBUG
 
 #include <linux/kernel.h>
 #include <linux/pci.h>
@@ -1356,6 +1356,63 @@ static void __init pcibios_allocate_resources(int pass)
         }
 }
 
+static void __init pcibios_reserve_legacy_regions(struct pci_bus *bus)
+{
+        struct pci_controller *hose = pci_bus_to_host(bus);
+        resource_size_t offset;
+        struct resource *res, *pres;
+        int i;
+
+        pr_debug("Reserving legacy ranges for domain %04x\n", pci_domain_nr(bus));
+
+        /* Check for IO */
+        if (!(hose->io_resource.flags & IORESOURCE_IO))
+                goto no_io;
+        offset = (unsigned long)hose->io_base_virt - _IO_BASE;
+        res = kzalloc(sizeof(struct resource), GFP_KERNEL);
+        BUG_ON(res == NULL);
+        res->name = "Legacy IO";
+        res->flags = IORESOURCE_IO;
+        res->start = offset;
+        res->end = (offset + 0xfff) & 0xfffffffful;
+        pr_debug("Candidate legacy IO: %pR\n", res);
+        if (request_resource(&hose->io_resource, res)) {
+                printk(KERN_DEBUG
+                       "PCI %04x:%02x Cannot reserve Legacy IO %pR\n",
+                       pci_domain_nr(bus), bus->number, res);
+                kfree(res);
+        }
+
+ no_io:
+        /* Check for memory */
+        offset = hose->pci_mem_offset;
+        pr_debug("hose mem offset: %016llx\n", (unsigned long long)offset);
+        for (i = 0; i < 3; i++) {
+                pres = &hose->mem_resources[i];
+                if (!(pres->flags & IORESOURCE_MEM))
+                        continue;
+                pr_debug("hose mem res: %pR\n", pres);
+                if ((pres->start - offset) <= 0xa0000 &&
+                    (pres->end - offset) >= 0xbffff)
+                        break;
+        }
+        if (i >= 3)
+                return;
+        res = kzalloc(sizeof(struct resource), GFP_KERNEL);
+        BUG_ON(res == NULL);
+        res->name = "Legacy VGA memory";
+        res->flags = IORESOURCE_MEM;
+        res->start = 0xa0000 + offset;
+        res->end = 0xbffff + offset;
+        pr_debug("Candidate VGA memory: %pR\n", res);
+        if (request_resource(pres, res)) {
+                printk(KERN_DEBUG
+                       "PCI %04x:%02x Cannot reserve VGA memory %pR\n",
+                       pci_domain_nr(bus), bus->number, res);
+                kfree(res);
+        }
+}
+
 void __init pcibios_resource_survey(void)
 {
         struct pci_bus *b;
@@ -1371,6 +1428,18 @@ void __init pcibios_resource_survey(void)
                 pcibios_allocate_resources(1);
         }
 
+        /* Before we start assigning unassigned resource, we try to reserve
+         * the low IO area and the VGA memory area if they intersect the
+         * bus available resources to avoid allocating things on top of them
+         */
+        if (!(ppc_pci_flags & PPC_PCI_PROBE_ONLY)) {
+                list_for_each_entry(b, &pci_root_buses, node)
+                        pcibios_reserve_legacy_regions(b);
+        }
+
+        /* Now, if the platform didn't decide to blindly trust the firmware,
+         * we proceed to assigning things that were left unassigned
+         */
         if (!(ppc_pci_flags & PPC_PCI_PROBE_ONLY)) {
                 pr_debug("PCI: Assigning unassigned resouces...\n");
                 pci_assign_unassigned_resources();