PCI : ability to relocate assigned pci-resources

Currently pci-bridges are allocated enough resources to satisfy their immediate
requirements.  Any additional resource-requests fail if additional free space,
contiguous to the one already allocated, is not available. This behavior is not
reasonable since sufficient contiguous resources, that can satisfy the request,
are available at a different location.

This patch provides the ability to expand and relocate a allocated resource.

	v2: Changelog: Fixed size calculation in pci_reassign_resource()
	v3: Changelog : Split this patch. The resource.c changes are already
			upstream. All the pci driver changes are in here.

Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

1 files changed, 95 insertions, 57 deletions

diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c
index 319f359906e8..51a9095c7da4 100644
--- a/drivers/pci/setup-res.c
+++ b/drivers/pci/setup-res.c
@@ -128,16 +128,16 @@ void pci_disable_bridge_window(struct pci_dev *dev)
 }
 #endif	/* CONFIG_PCI_QUIRKS */
 
+
+
 static int __pci_assign_resource(struct pci_bus *bus, struct pci_dev *dev,
-				 int resno)
+		int resno, resource_size_t size, resource_size_t align)
 {
 	struct resource *res = dev->resource + resno;
-	resource_size_t size, min, align;
+	resource_size_t min;
 	int ret;
 
-	size = resource_size(res);
 	min = (res->flags & IORESOURCE_IO) ? PCIBIOS_MIN_IO : PCIBIOS_MIN_MEM;
-	align = pci_resource_alignment(dev, res);
 
 	/* First, try exact prefetching match.. */
 	ret = pci_bus_alloc_resource(bus, res, size, align, min,
@@ -154,56 +154,101 @@ static int __pci_assign_resource(struct pci_bus *bus, struct pci_dev *dev,
 		ret = pci_bus_alloc_resource(bus, res, size, align, min, 0,
 					     pcibios_align_resource, dev);
 	}
+	return ret;
+}
 
-	if (ret < 0 && dev->fw_addr[resno]) {
-		struct resource *root, *conflict;
-		resource_size_t start, end;
+static int pci_revert_fw_address(struct resource *res, struct pci_dev *dev, 
+		int resno, resource_size_t size)
+{
+	struct resource *root, *conflict;
+	resource_size_t start, end;
+	int ret = 0;
 
-		/*
-		 * If we failed to assign anything, let's try the address
-		 * where firmware left it.  That at least has a chance of
-		 * working, which is better than just leaving it disabled.
-		 */
+	if (res->flags & IORESOURCE_IO)
+		root = &ioport_resource;
+	else
+		root = &iomem_resource;
+
+	start = res->start;
+	end = res->end;
+	res->start = dev->fw_addr[resno];
+	res->end = res->start + size - 1;
+	dev_info(&dev->dev, "BAR %d: trying firmware assignment %pR\n",
+		 resno, res);
+	conflict = request_resource_conflict(root, res);
+	if (conflict) {
+		dev_info(&dev->dev,
+			 "BAR %d: %pR conflicts with %s %pR\n", resno,
+			 res, conflict->name, conflict);
+		res->start = start;
+		res->end = end;
+		ret = 1;
+	}
+	return ret;
+}
+
+static int _pci_assign_resource(struct pci_dev *dev, int resno, int size, resource_size_t min_align)
+{
+	struct resource *res = dev->resource + resno;
+	struct pci_bus *bus;
+	int ret;
+	char *type;
 
-		if (res->flags & IORESOURCE_IO)
-			root = &ioport_resource;
+	bus = dev->bus;
+	while ((ret = __pci_assign_resource(bus, dev, resno, size, min_align))) {
+		if (!bus->parent || !bus->self->transparent)
+			break;
+		bus = bus->parent;
+	}
+
+	if (ret) {
+		if (res->flags & IORESOURCE_MEM)
+			if (res->flags & IORESOURCE_PREFETCH)
+				type = "mem pref";
+			else
+				type = "mem";
+		else if (res->flags & IORESOURCE_IO)
+			type = "io";
 		else
-			root = &iomem_resource;
-
-		start = res->start;
-		end = res->end;
-		res->start = dev->fw_addr[resno];
-		res->end = res->start + size - 1;
-		dev_info(&dev->dev, "BAR %d: trying firmware assignment %pR\n",
-			 resno, res);
-		conflict = request_resource_conflict(root, res);
-		if (conflict) {
-			dev_info(&dev->dev,
-				 "BAR %d: %pR conflicts with %s %pR\n", resno,
-				 res, conflict->name, conflict);
-			res->start = start;
-			res->end = end;
-		} else
-			ret = 0;
+			type = "unknown";
+		dev_info(&dev->dev,
+			 "BAR %d: can't assign %s (size %#llx)\n",
+			 resno, type, (unsigned long long) resource_size(res));
 	}
 
+	return ret;
+}
+
+int pci_reassign_resource(struct pci_dev *dev, int resno, resource_size_t addsize,
+			resource_size_t min_align)
+{
+	struct resource *res = dev->resource + resno;
+	resource_size_t new_size;
+	int ret;
+
+	if (!res->parent) {
+		dev_info(&dev->dev, "BAR %d: can't reassign an unassigned resouce %pR "
+			 "\n", resno, res);
+		return -EINVAL;
+	}
+
+	new_size = resource_size(res) + addsize + min_align;
+	ret = _pci_assign_resource(dev, resno, new_size, min_align);
 	if (!ret) {
 		res->flags &= ~IORESOURCE_STARTALIGN;
 		dev_info(&dev->dev, "BAR %d: assigned %pR\n", resno, res);
 		if (resno < PCI_BRIDGE_RESOURCES)
 			pci_update_resource(dev, resno);
 	}
-
 	return ret;
 }
 
 int pci_assign_resource(struct pci_dev *dev, int resno)
 {
 	struct resource *res = dev->resource + resno;
-	resource_size_t align;
+	resource_size_t align, size;
 	struct pci_bus *bus;
 	int ret;
-	char *type;
 
 	align = pci_resource_alignment(dev, res);
 	if (!align) {
@@ -213,34 +258,27 @@ int pci_assign_resource(struct pci_dev *dev, int resno)
 	}
 
 	bus = dev->bus;
-	while ((ret = __pci_assign_resource(bus, dev, resno))) {
-		if (bus->parent && bus->self->transparent)
-			bus = bus->parent;
-		else
-			bus = NULL;
-		if (bus)
-			continue;
-		break;
-	}
+	size = resource_size(res);
+	ret = _pci_assign_resource(dev, resno, size, align);
 
-	if (ret) {
-		if (res->flags & IORESOURCE_MEM)
-			if (res->flags & IORESOURCE_PREFETCH)
-				type = "mem pref";
-			else
-				type = "mem";
-		else if (res->flags & IORESOURCE_IO)
-			type = "io";
-		else
-			type = "unknown";
-		dev_info(&dev->dev,
-			 "BAR %d: can't assign %s (size %#llx)\n",
-			 resno, type, (unsigned long long) resource_size(res));
-	}
+	/*
+	 * If we failed to assign anything, let's try the address
+	 * where firmware left it.  That at least has a chance of
+	 * working, which is better than just leaving it disabled.
+	 */
+	if (ret < 0 && dev->fw_addr[resno])
+		ret = pci_revert_fw_address(res, dev, resno, size);
 
+	if (!ret) {
+		res->flags &= ~IORESOURCE_STARTALIGN;
+		dev_info(&dev->dev, "BAR %d: assigned %pR\n", resno, res);
+		if (resno < PCI_BRIDGE_RESOURCES)
+			pci_update_resource(dev, resno);
+	}
 	return ret;
 }
 
+
 /* Sort resources by alignment */
 void pdev_sort_resources(struct pci_dev *dev, struct resource_list *head)
 {