[PATCH RFC v4 04/21] PCI: Define PCI-specific version of the release_child_resources()

[Sergey Miroshnichenko]

Make the released resources of a bridge valid for later re-assignment:
clear the STARTALIGN flag.

Resources marked with PCI_FIXED must preserve their offset and size.

Signed-off-by: Sergey Miroshnichenko <s.miroshnichenko at yadro.com>
---
 drivers/pci/setup-bus.c | 47 ++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 46 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index ec44a0f3a7ac..3644feb13179 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -1483,6 +1483,51 @@ static void __pci_bridge_assign_resources(const struct pci_dev *bridge,
 	(IORESOURCE_IO | IORESOURCE_MEM | IORESOURCE_PREFETCH |\
 	 IORESOURCE_MEM_64)
 
+/*
+ * Similar to release_child_resources(), but aware of PCI_FIXED and STARTALIGN flags
+ */
+static void pci_release_child_resources(struct resource *r)
+{
+	struct resource *tmp, *p;
+
+	if (!r)
+		return;
+
+	if (r->flags & IORESOURCE_PCI_FIXED)
+		return;
+
+	p = r->child;
+	r->child = NULL;
+	while (p) {
+		resource_size_t size = resource_size(p);
+
+		tmp = p;
+		p = p->sibling;
+
+		tmp->parent = NULL;
+		tmp->sibling = NULL;
+		pci_release_child_resources(tmp);
+
+		if (!tmp->flags)
+			continue;
+
+		if (tmp->flags & IORESOURCE_PCI_FIXED) {
+			pr_debug("PCI: release fixed %pR (%s), keep its flags, base and size\n",
+				 tmp, tmp->name);
+			continue;
+		}
+
+		pr_debug("PCI: release %pR (%s)\n", tmp, tmp->name);
+
+		/* need to restore size, and keep all the flags but STARTALIGN */
+		tmp->start = 0;
+		tmp->end = size - 1;
+
+		tmp->flags &= ~IORESOURCE_STARTALIGN;
+		tmp->flags |= IORESOURCE_SIZEALIGN;
+	}
+}
+
 static void pci_bridge_release_resources(struct pci_bus *bus,
 					  unsigned long type)
 {
@@ -1528,7 +1573,7 @@ static void pci_bridge_release_resources(struct pci_bus *bus,
 	 * if there are children under that, we should release them
 	 *  all
 	 */
-	release_child_resources(r);
+	pci_release_child_resources(r);
 	if (!release_resource(r)) {
 		type = old_flags = r->flags & PCI_RES_TYPE_MASK;
 		pci_printk(KERN_DEBUG, dev, "resource %d %pR released\n",
-- 
2.20.1