[PATCH v8 15/24] PCI: hotplug: Sort fixed BARs before assignment

[Sergei Miroshnichenko <s.miroshnichenko@xxxxxxxxx>]

Fixed BARs and bridge windows containing fixed BARs must be assigned before
the movable ones.

When assigning a fixed BAR/bridge window, its start address is chosen to be
the lowest possible. To prevent conflicts, sort such resources based on the
start address of their fixed areas.

Add support of fixed BARs and bridge windows to pdev_sort_resources().

Signed-off-by: Sergei Miroshnichenko <s.miroshnichenko@xxxxxxxxx>
---
 drivers/pci/setup-bus.c | 63 +++++++++++++++++++++++++++++++++++------
 1 file changed, 54 insertions(+), 9 deletions(-)

diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index 1f76a4dffb7d..4cadfa1f9519 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -124,7 +124,8 @@ static resource_size_t get_res_add_align(struct list_head *head,
 
 
 /* Sort resources by alignment */
-static void pdev_sort_resources(struct pci_dev *dev, struct list_head *head)
+static void pdev_sort_resources(struct pci_dev *dev, struct list_head *head,
+				struct list_head *head_fixed)
 {
 	int i;
 
@@ -133,17 +134,27 @@ static void pdev_sort_resources(struct pci_dev *dev, struct list_head *head)
 		struct pci_dev_resource *dev_res, *tmp;
 		resource_size_t r_align;
 		struct list_head *n;
+		struct resource *fixed_res = NULL;
 
 		r = &dev->resource[i];
 
-		if (r->flags & IORESOURCE_PCI_FIXED)
-			continue;
-
 		if (!(r->flags) || r->parent || !pci_dev_bar_enabled(dev, i))
 			continue;
 
+		if (i >= PCI_BRIDGE_RESOURCES &&
+		    dev->subordinate) {
+			int idx = i - PCI_BRIDGE_RESOURCES;
+
+			fixed_res = &dev->subordinate->fixed_range[idx];
+		} else if (pci_dev_bar_fixed(dev, r)) {
+			fixed_res = r;
+		}
+
+		if (fixed_res && !pci_fixed_range_valid(fixed_res))
+			fixed_res = NULL;
+
 		r_align = pci_resource_alignment(dev, r);
-		if (!r_align) {
+		if (!r_align && !fixed_res) {
 			pci_warn(dev, "BAR %d: %pR has bogus alignment\n",
 				 i, r);
 			continue;
@@ -155,6 +166,30 @@ static void pdev_sort_resources(struct pci_dev *dev, struct list_head *head)
 		tmp->res = r;
 		tmp->dev = dev;
 
+		if (fixed_res) {
+			n = head_fixed;
+			list_for_each_entry(dev_res, head_fixed, list) {
+				struct resource *c_fixed_res = NULL;
+				int c_resno = dev_res->res - dev_res->dev->resource;
+				int br_idx = c_resno - PCI_BRIDGE_RESOURCES;
+				struct pci_bus *cbus = dev_res->dev->subordinate;
+
+				if (br_idx >= 0)
+					c_fixed_res = &cbus->fixed_range[br_idx];
+				else
+					c_fixed_res = dev_res->res;
+
+				if (fixed_res->start < c_fixed_res->start) {
+					n = &dev_res->list;
+					break;
+				}
+			}
+			/* Insert it just before n */
+			list_add_tail(&tmp->list, n);
+
+			continue;
+		}
+
 		/* Fallback is smallest one or list is empty */
 		n = head;
 		list_for_each_entry(dev_res, head, list) {
@@ -173,7 +208,8 @@ static void pdev_sort_resources(struct pci_dev *dev, struct list_head *head)
 	}
 }
 
-static void __dev_sort_resources(struct pci_dev *dev, struct list_head *head)
+static void __dev_sort_resources(struct pci_dev *dev, struct list_head *head,
+				 struct list_head *head_fixed)
 {
 	u16 class = dev->class >> 8;
 
@@ -189,7 +225,7 @@ static void __dev_sort_resources(struct pci_dev *dev, struct list_head *head)
 			return;
 	}
 
-	pdev_sort_resources(dev, head);
+	pdev_sort_resources(dev, head, head_fixed);
 }
 
 static inline void reset_resource(struct resource *res)
@@ -484,8 +520,13 @@ static void pdev_assign_resources_sorted(struct pci_dev *dev,
 					 struct list_head *fail_head)
 {
 	LIST_HEAD(head);
+	LIST_HEAD(head_fixed);
+
+	__dev_sort_resources(dev, &head, &head_fixed);
+
+	if (!list_empty(&head_fixed))
+		__assign_resources_sorted(&head_fixed, NULL, NULL);
 
-	__dev_sort_resources(dev, &head);
 	__assign_resources_sorted(&head, add_head, fail_head);
 
 }
@@ -496,9 +537,13 @@ static void pbus_assign_resources_sorted(const struct pci_bus *bus,
 {
 	struct pci_dev *dev;
 	LIST_HEAD(head);
+	LIST_HEAD(head_fixed);
 
 	list_for_each_entry(dev, &bus->devices, bus_list)
-		__dev_sort_resources(dev, &head);
+		__dev_sort_resources(dev, &head, &head_fixed);
+
+	if (!list_empty(&head_fixed))
+		__assign_resources_sorted(&head_fixed, NULL, NULL);
 
 	__assign_resources_sorted(&head, realloc_head, fail_head);
 }
-- 
2.24.1