Merge remote-tracking branches 'spi/topic/orion', 'spi/topic/pxa2xx', 'spi/topic...

[linux-2.6-block.git] / drivers / pci / bus.c

diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c
index 73aef51a28f0760fefa6b4344235e7f341bebb3d..8fb16188cd82aaff9d346a70f46e0257e468fe29 100644 (file)
--- a/drivers/pci/bus.c
+++ b/drivers/pci/bus.c
@@ -228,6 +228,49 @@ int pci_bus_alloc_resource(struct pci_bus *bus, struct resource *res,
 }
 EXPORT_SYMBOL(pci_bus_alloc_resource);
 
+/*
+ * The @idx resource of @dev should be a PCI-PCI bridge window.  If this
+ * resource fits inside a window of an upstream bridge, do nothing.  If it
+ * overlaps an upstream window but extends outside it, clip the resource so
+ * it fits completely inside.
+ */
+bool pci_bus_clip_resource(struct pci_dev *dev, int idx)
+{
+       struct pci_bus *bus = dev->bus;
+       struct resource *res = &dev->resource[idx];
+       struct resource orig_res = *res;
+       struct resource *r;
+       int i;
+
+       pci_bus_for_each_resource(bus, r, i) {
+               resource_size_t start, end;
+
+               if (!r)
+                       continue;
+
+               if (resource_type(res) != resource_type(r))
+                       continue;
+
+               start = max(r->start, res->start);
+               end = min(r->end, res->end);
+
+               if (start > end)
+                       continue;       /* no overlap */
+
+               if (res->start == start && res->end == end)
+                       return false;   /* no change */
+
+               res->start = start;
+               res->end = end;
+               dev_printk(KERN_DEBUG, &dev->dev, "%pR clipped to %pR\n",
+                                &orig_res, res);
+
+               return true;
+       }
+
+       return false;
+}
+
 void __weak pcibios_resource_survey_bus(struct pci_bus *bus) { }
 
 /**