PCI: add pci_bridge_release_resources and pci_bus_release_bridge_resources

We use this in later patches to free resrouce ranges for reassignment in
an effort to support a wider variety of PCI topologies.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Reviewed-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

1 files changed, 82 insertions, 0 deletions

diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index 52fbd426a1c..7371a5479a9 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -604,6 +604,88 @@ void __ref pci_bus_assign_resources(const struct pci_bus *bus)
 }
 EXPORT_SYMBOL(pci_bus_assign_resources);
 
+static void pci_bridge_release_resources(struct pci_bus *bus,
+                                          unsigned long type)
+{
+        int idx;
+        bool changed = false;
+        struct pci_dev *dev;
+        struct resource *r;
+        unsigned long type_mask = IORESOURCE_IO | IORESOURCE_MEM |
+                                  IORESOURCE_PREFETCH;
+
+        dev = bus->self;
+        for (idx = PCI_BRIDGE_RESOURCES; idx <= PCI_BRIDGE_RESOURCE_END;
+             idx++) {
+                r = &dev->resource[idx];
+                if ((r->flags & type_mask) != type)
+                        continue;
+                if (!r->parent)
+                        continue;
+                /*
+                 * if there are children under that, we should release them
+                 *  all
+                 */
+                release_child_resources(r);
+                if (!release_resource(r)) {
+                        dev_printk(KERN_DEBUG, &dev->dev,
+                                 "resource %d %pR released\n", idx, r);
+                        /* keep the old size */
+                        r->end = resource_size(r) - 1;
+                        r->start = 0;
+                        r->flags = 0;
+                        changed = true;
+                }
+        }
+
+        if (changed) {
+                /* avoiding touch the one without PREF */
+                if (type & IORESOURCE_PREFETCH)
+                        type = IORESOURCE_PREFETCH;
+                __pci_setup_bridge(bus, type);
+        }
+}
+
+enum release_type {
+        leaf_only,
+        whole_subtree,
+};
+/*
+ * try to release pci bridge resources that is from leaf bridge,
+ * so we can allocate big new one later
+ */
+static void __ref pci_bus_release_bridge_resources(struct pci_bus *bus,
+                                                   unsigned long type,
+                                                   enum release_type rel_type)
+{
+        struct pci_dev *dev;
+        bool is_leaf_bridge = true;
+
+        list_for_each_entry(dev, &bus->devices, bus_list) {
+                struct pci_bus *b = dev->subordinate;
+                if (!b)
+                        continue;
+
+                is_leaf_bridge = false;
+
+                if ((dev->class >> 8) != PCI_CLASS_BRIDGE_PCI)
+                        continue;
+
+                if (rel_type == whole_subtree)
+                        pci_bus_release_bridge_resources(b, type,
+                                                 whole_subtree);
+        }
+
+        if (pci_is_root_bus(bus))
+                return;
+
+        if ((bus->self->class >> 8) != PCI_CLASS_BRIDGE_PCI)
+                return;
+
+        if ((rel_type == whole_subtree) || is_leaf_bridge)
+                pci_bridge_release_resources(bus, type);
+}
+
 static void pci_bus_dump_res(struct pci_bus *bus)
 {
         int i;