1 files changed, 102 insertions, 30 deletions

diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c
index a037d81f21ed..00660cc502c5 100644
--- a/drivers/pci/bus.c
+++ b/drivers/pci/bus.c
@@ -98,41 +98,54 @@ void pci_bus_remove_resources(struct pci_bus *bus)
 	}
 }
 
-/**
- * pci_bus_alloc_resource - allocate a resource from a parent bus
- * @bus: PCI bus
- * @res: resource to allocate
- * @size: size of resource to allocate
- * @align: alignment of resource to allocate
- * @min: minimum /proc/iomem address to allocate
- * @type_mask: IORESOURCE_* type flags
- * @alignf: resource alignment function
- * @alignf_data: data argument for resource alignment function
- *
- * Given the PCI bus a device resides on, the size, minimum address,
- * alignment and type, try to find an acceptable resource allocation
- * for a specific device resource.
+static struct pci_bus_region pci_32_bit = {0, 0xffffffffULL};
+#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
+static struct pci_bus_region pci_64_bit = {0,
+				(dma_addr_t) 0xffffffffffffffffULL};
+static struct pci_bus_region pci_high = {(dma_addr_t) 0x100000000ULL,
+				(dma_addr_t) 0xffffffffffffffffULL};
+#endif
+
+/*
+ * @res contains CPU addresses.  Clip it so the corresponding bus addresses
+ * on @bus are entirely within @region.  This is used to control the bus
+ * addresses of resources we allocate, e.g., we may need a resource that
+ * can be mapped by a 32-bit BAR.
  */
-int
-pci_bus_alloc_resource(struct pci_bus *bus, struct resource *res,
+static void pci_clip_resource_to_region(struct pci_bus *bus,
+					struct resource *res,
+					struct pci_bus_region *region)
+{
+	struct pci_bus_region r;
+
+	pcibios_resource_to_bus(bus, &r, res);
+	if (r.start < region->start)
+		r.start = region->start;
+	if (r.end > region->end)
+		r.end = region->end;
+
+	if (r.end < r.start)
+		res->end = res->start - 1;
+	else
+		pcibios_bus_to_resource(bus, res, &r);
+}
+
+static int pci_bus_alloc_from_region(struct pci_bus *bus, struct resource *res,
 		resource_size_t size, resource_size_t align,
 		resource_size_t min, unsigned int type_mask,
 		resource_size_t (*alignf)(void *,
 					  const struct resource *,
 					  resource_size_t,
 					  resource_size_t),
-		void *alignf_data)
+		void *alignf_data,
+		struct pci_bus_region *region)
 {
-	int i, ret = -ENOMEM;
-	struct resource *r;
-	resource_size_t max = -1;
+	int i, ret;
+	struct resource *r, avail;
+	resource_size_t max;
 
 	type_mask |= IORESOURCE_IO | IORESOURCE_MEM;
 
-	/* don't allocate too high if the pref mem doesn't support 64bit*/
-	if (!(res->flags & IORESOURCE_MEM_64))
-		max = PCIBIOS_MAX_MEM_32;
-
 	pci_bus_for_each_resource(bus, r, i) {
 		if (!r)
 			continue;
@@ -147,15 +160,74 @@ pci_bus_alloc_resource(struct pci_bus *bus, struct resource *res,
 		    !(res->flags & IORESOURCE_PREFETCH))
 			continue;
 
+		avail = *r;
+		pci_clip_resource_to_region(bus, &avail, region);
+		if (!resource_size(&avail))
+			continue;
+
+		/*
+		 * "min" is typically PCIBIOS_MIN_IO or PCIBIOS_MIN_MEM to
+		 * protect badly documented motherboard resources, but if
+		 * this is an already-configured bridge window, its start
+		 * overrides "min".
+		 */
+		if (avail.start)
+			min = avail.start;
+
+		max = avail.end;
+
 		/* Ok, try it out.. */
-		ret = allocate_resource(r, res, size,
-					r->start ? : min,
-					max, align,
-					alignf, alignf_data);
+		ret = allocate_resource(r, res, size, min, max,
+					align, alignf, alignf_data);
 		if (ret == 0)
-			break;
+			return 0;
 	}
-	return ret;
+	return -ENOMEM;
+}
+
+/**
+ * pci_bus_alloc_resource - allocate a resource from a parent bus
+ * @bus: PCI bus
+ * @res: resource to allocate
+ * @size: size of resource to allocate
+ * @align: alignment of resource to allocate
+ * @min: minimum /proc/iomem address to allocate
+ * @type_mask: IORESOURCE_* type flags
+ * @alignf: resource alignment function
+ * @alignf_data: data argument for resource alignment function
+ *
+ * Given the PCI bus a device resides on, the size, minimum address,
+ * alignment and type, try to find an acceptable resource allocation
+ * for a specific device resource.
+ */
+int pci_bus_alloc_resource(struct pci_bus *bus, struct resource *res,
+		resource_size_t size, resource_size_t align,
+		resource_size_t min, unsigned int type_mask,
+		resource_size_t (*alignf)(void *,
+					  const struct resource *,
+					  resource_size_t,
+					  resource_size_t),
+		void *alignf_data)
+{
+#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
+	int rc;
+
+	if (res->flags & IORESOURCE_MEM_64) {
+		rc = pci_bus_alloc_from_region(bus, res, size, align, min,
+					       type_mask, alignf, alignf_data,
+					       &pci_high);
+		if (rc == 0)
+			return 0;
+
+		return pci_bus_alloc_from_region(bus, res, size, align, min,
+						 type_mask, alignf, alignf_data,
+						 &pci_64_bit);
+	}
+#endif
+
+	return pci_bus_alloc_from_region(bus, res, size, align, min,
+					 type_mask, alignf, alignf_data,
+					 &pci_32_bit);
 }
 
 void __weak pcibios_resource_survey_bus(struct pci_bus *bus) { }