PCI: Consider additional PF's IOV BAR alignment in sizing and assigning

When sizing and assigning resources, we divide the resources into two
lists: the requested list and the additional list.  We don't consider the
alignment of additional VF(n) BAR space.

This is because the alignment required for the VF(n) BAR space is the size
of an individual VF BAR, not the size of the space for *all* VFs.  But we
want additional alignment to support partitioning on PowerNV.

Consider the additional IOV BAR alignment when sizing and assigning
resources.  When there is not enough system MMIO space to accomodate both
the requested list and the additional list, the PF's IOV BAR alignment will
not contribute to the bridge. When there is enough system MMIO space for
both lists, the additional alignment will contribute to the bridge.

The additional alignment is stored in the min_align of pci_dev_resource,
which is stored in the additional list by add_to_list() at the end of
pbus_size_mem(). The additional alignment is calculated in
pci_resource_alignment().  For an IOV BAR, we have arch dependent function
to get the alignment for different arch.

[bhelgaas: changelog, printk cast]
Signed-off-by: Wei Yang <weiyang@linux.vnet.ibm.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

drivers/pci/setup-bus.c

@@ -99,8 +99,8 @@ static void remove_from_list(struct list_head *head,
 	}
 }
 
-static resource_size_t get_res_add_size(struct list_head *head,
+static struct pci_dev_resource *res_to_dev_res(struct list_head *head,
-					struct resource *res)
+					       struct resource *res)
 {
 	struct pci_dev_resource *dev_res;
 
@@ -109,17 +109,37 @@ static resource_size_t get_res_add_size(struct list_head *head,
 			int idx = res - &dev_res->dev->resource[0];
 
 			dev_printk(KERN_DEBUG, &dev_res->dev->dev,
-				 "res[%d]=%pR get_res_add_size add_size %llx\n",
+				 "res[%d]=%pR res_to_dev_res add_size %llx min_align %llx\n",
 				 idx, dev_res->res,
-				 (unsigned long long)dev_res->add_size);
+				 (unsigned long long)dev_res->add_size,
+				 (unsigned long long)dev_res->min_align);
 
-			return dev_res->add_size;
+			return dev_res;
 		}
 	}
 
-	return 0;
+	return NULL;
 }
 
+static resource_size_t get_res_add_size(struct list_head *head,
+					struct resource *res)
+{
+	struct pci_dev_resource *dev_res;
+
+	dev_res = res_to_dev_res(head, res);
+	return dev_res ? dev_res->add_size : 0;
+}
+
+static resource_size_t get_res_add_align(struct list_head *head,
+					 struct resource *res)
+{
+	struct pci_dev_resource *dev_res;
+
+	dev_res = res_to_dev_res(head, res);
+	return dev_res ? dev_res->min_align : 0;
+}
+
+
 /* Sort resources by alignment */
 static void pdev_sort_resources(struct pci_dev *dev, struct list_head *head)
 {
@@ -215,7 +235,7 @@ static void reassign_resources_sorted(struct list_head *realloc_head,
 	struct resource *res;
 	struct pci_dev_resource *add_res, *tmp;
 	struct pci_dev_resource *dev_res;
-	resource_size_t add_size;
+	resource_size_t add_size, align;
 	int idx;
 
 	list_for_each_entry_safe(add_res, tmp, realloc_head, list) {
@@ -238,13 +258,13 @@ static void reassign_resources_sorted(struct list_head *realloc_head,
 
 		idx = res - &add_res->dev->resource[0];
 		add_size = add_res->add_size;
+		align = add_res->min_align;
 		if (!resource_size(res)) {
-			res->start = add_res->start;
+			res->start = align;
 			res->end = res->start + add_size - 1;
 			if (pci_assign_resource(add_res->dev, idx))
 				reset_resource(res);
 		} else {
-			resource_size_t align = add_res->min_align;
 			res->flags |= add_res->flags &
 				 (IORESOURCE_STARTALIGN|IORESOURCE_SIZEALIGN);
 			if (pci_reassign_resource(add_res->dev, idx,
@@ -368,8 +388,9 @@ static void __assign_resources_sorted(struct list_head *head,
 	LIST_HEAD(save_head);
 	LIST_HEAD(local_fail_head);
 	struct pci_dev_resource *save_res;
-	struct pci_dev_resource *dev_res, *tmp_res;
+	struct pci_dev_resource *dev_res, *tmp_res, *dev_res2;
 	unsigned long fail_type;
+	resource_size_t add_align, align;
 
 	/* Check if optional add_size is there */
 	if (!realloc_head || list_empty(realloc_head))
@@ -384,10 +405,44 @@ static void __assign_resources_sorted(struct list_head *head,
 	}
 
 	/* Update res in head list with add_size in realloc_head list */
-	list_for_each_entry(dev_res, head, list)
+	list_for_each_entry_safe(dev_res, tmp_res, head, list) {
 		dev_res->res->end += get_res_add_size(realloc_head,
 							dev_res->res);
 
+		/*
+		 * There are two kinds of additional resources in the list:
+		 * 1. bridge resource  -- IORESOURCE_STARTALIGN
+		 * 2. SR-IOV resource   -- IORESOURCE_SIZEALIGN
+		 * Here just fix the additional alignment for bridge
+		 */
+		if (!(dev_res->res->flags & IORESOURCE_STARTALIGN))
+			continue;
+
+		add_align = get_res_add_align(realloc_head, dev_res->res);
+
+		/*
+		 * The "head" list is sorted by the alignment to make sure
+		 * resources with bigger alignment will be assigned first.
+		 * After we change the alignment of a dev_res in "head" list,
+		 * we need to reorder the list by alignment to make it
+		 * consistent.
+		 */
+		if (add_align > dev_res->res->start) {
+			dev_res->res->start = add_align;
+			dev_res->res->end = add_align +
+				            resource_size(dev_res->res);
+
+			list_for_each_entry(dev_res2, head, list) {
+				align = pci_resource_alignment(dev_res2->dev,
+							       dev_res2->res);
+				if (add_align > align)
+					list_move_tail(&dev_res->list,
+						       &dev_res2->list);
+			}
+               }
+
+	}
+
 	/* Try updated head list with add_size added */
 	assign_requested_resources_sorted(head, &local_fail_head);
 
@@ -962,6 +1017,8 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask,
 	struct resource *b_res = find_free_bus_resource(bus,
 					mask | IORESOURCE_PREFETCH, type);
 	resource_size_t children_add_size = 0;
+	resource_size_t children_add_align = 0;
+	resource_size_t add_align = 0;
 
 	if (!b_res)
 		return -ENOSPC;
@@ -986,6 +1043,7 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask,
 			/* put SRIOV requested res to the optional list */
 			if (realloc_head && i >= PCI_IOV_RESOURCES &&
 					i <= PCI_IOV_RESOURCE_END) {
+				add_align = max(pci_resource_alignment(dev, r), add_align);
 				r->end = r->start - 1;
 				add_to_list(realloc_head, dev, r, r_size, 0/* don't care */);
 				children_add_size += r_size;
@@ -1016,19 +1074,23 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask,
 			if (order > max_order)
 				max_order = order;
 
-			if (realloc_head)
+			if (realloc_head) {
 				children_add_size += get_res_add_size(realloc_head, r);
+				children_add_align = get_res_add_align(realloc_head, r);
+				add_align = max(add_align, children_add_align);
+			}
 		}
 	}
 
 	min_align = calculate_mem_align(aligns, max_order);
 	min_align = max(min_align, window_alignment(bus, b_res->flags));
 	size0 = calculate_memsize(size, min_size, 0, resource_size(b_res), min_align);
+	add_align = max(min_align, add_align);
 	if (children_add_size > add_size)
 		add_size = children_add_size;
 	size1 = (!realloc_head || (realloc_head && !add_size)) ? size0 :
 		calculate_memsize(size, min_size, add_size,
-				resource_size(b_res), min_align);
+				resource_size(b_res), add_align);
 	if (!size0 && !size1) {
 		if (b_res->start || b_res->end)
 			dev_info(&bus->self->dev, "disabling bridge window %pR to %pR (unused)\n",
@@ -1040,10 +1102,11 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask,
 	b_res->end = size0 + min_align - 1;
 	b_res->flags |= IORESOURCE_STARTALIGN;
 	if (size1 > size0 && realloc_head) {
-		add_to_list(realloc_head, bus->self, b_res, size1-size0, min_align);
+		add_to_list(realloc_head, bus->self, b_res, size1-size0, add_align);
-		dev_printk(KERN_DEBUG, &bus->self->dev, "bridge window %pR to %pR add_size %llx\n",
+		dev_printk(KERN_DEBUG, &bus->self->dev, "bridge window %pR to %pR add_size %llx add_align %llx\n",
 			   b_res, &bus->busn_res,
-			   (unsigned long long)size1-size0);
+			   (unsigned long long) (size1 - size0),
+			   (unsigned long long) add_align);
 	}
 	return 0;
 }