[PATCH 05/11] pci: update bridge res to get more big range in pci assign unssign

[Yinghai Lu <yinghai@kernel.org>]

BIOS separate IO range between several IOHs, and on some slots, BIOS assign the
resource to the bridge, but stop assigning resource to the device under that
bridge, because the device need big resource.

1. pci assign unassign and record the failed device resource.
2. clear the BIOS assigned resource of the parent bridge of fail device
3. go back and call pci assign unsigned
4. if it still fail, will go up more bridges. and clear and try again.

use pci_try_num to control back track bridge levels.

-v2: update it with resource_list_x
-v3: make pci_try_num default to 1. and when pci_try_num is set to more than 1
     will check it with max_depth, and adjust that to make sure it is bigger
     enough
-v4: update to enum release_type and _used_calling

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
---
 drivers/pci/pci.c       |    5 ++
 drivers/pci/pci.h       |    2 +
 drivers/pci/setup-bus.c |  117 ++++++++++++++++++++++++++++++++++++++++++++++-
 3 files changed, 123 insertions(+), 1 deletions(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index d62a5de..9dc358d 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -2951,6 +2951,11 @@ static int __init pci_setup(char *str)
 				pci_no_aer();
 			} else if (!strcmp(str, "nodomains")) {
 				pci_no_domains();
+			} else if (!strncmp(str, "try=", 4)) {
+				int try_num = memparse(str + 4, &str);
+
+				if (try_num > 0 && try_num < 16)
+					pci_try_num = try_num;
 			} else if (!strncmp(str, "cbiosize=", 9)) {
 				pci_cardbus_io_size = memparse(str + 9, &str);
 			} else if (!strncmp(str, "cbmemsize=", 10)) {
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 4eb10f4..f6582c4 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -212,6 +212,8 @@ static inline int pci_ari_enabled(struct pci_bus *bus)
 	return bus->self && bus->self->ari_enabled;
 }
 
+extern int pci_try_num;
+
 #ifdef CONFIG_PCI_QUIRKS
 extern int pci_is_reassigndev(struct pci_dev *dev);
 resource_size_t pci_specified_resource_alignment(struct pci_dev *dev);
diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index 5eebec8..8ad515e 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -798,11 +798,69 @@ static void pci_bus_dump_resources(struct pci_bus *bus)
 	}
 }
 
+static int __init pci_bus_get_depth(struct pci_bus *bus)
+{
+	int depth = 0;
+	struct pci_dev *dev;
+
+	list_for_each_entry(dev, &bus->devices, bus_list) {
+		int ret;
+		struct pci_bus *b = dev->subordinate;
+		if (!b)
+			continue;
+
+		ret = pci_bus_get_depth(b);
+		if (ret + 1 > depth)
+			depth = ret + 1;
+	}
+
+	return depth;
+}
+static int __init pci_get_max_depth(void)
+{
+	int depth = 0;
+	struct pci_bus *bus;
+
+	list_for_each_entry(bus, &pci_root_buses, node) {
+		int ret;
+
+		ret = pci_bus_get_depth(bus);
+		if (ret > depth)
+			depth = ret;
+	}
+
+	return depth;
+}
+
+/*
+ * first try will not touch pci bridge res
+ * second try will clear small leaf bridge res
+ * third try will clear related bridge: some aggressive
+ */
+int pci_try_num = 1;
 void __init
 pci_assign_unassigned_resources(void)
 {
 	struct pci_bus *bus;
+	int tried_times = 0;
+	enum release_type rel_type = leaf_only;
+	struct resource_list_x head, *list;
+	unsigned long type_mask = IORESOURCE_IO | IORESOURCE_MEM |
+				  IORESOURCE_PREFETCH;
+	unsigned long failed_type;
+	int max_depth = pci_get_max_depth();
+
+	head.next = NULL;
+
+	if (pci_try_num > 1) {
+		if (max_depth + 1 > pci_try_num)
+			pci_try_num = max_depth + 1;
+	}
+
+	printk(KERN_DEBUG "PCI: max depth: %d pci_try_num: %d\n",
+		 max_depth, pci_try_num);
 
+again:
 	/* Depth first, calculate sizes and alignments of all
 	   subordinate buses. */
 	list_for_each_entry(bus, &pci_root_buses, node) {
@@ -810,7 +868,64 @@ pci_assign_unassigned_resources(void)
 	}
 	/* Depth last, allocate resources and update the hardware. */
 	list_for_each_entry(bus, &pci_root_buses, node) {
-		pci_bus_assign_resources(bus);
+		__pci_bus_assign_resources(bus, &head);
+	}
+	tried_times++;
+
+	/* any device complain? */
+	if (!head.next)
+		goto enable_and_dump;
+	failed_type = 0;
+	for (list = head.next; list;) {
+		failed_type |= list->flags;
+		list = list->next;
+	}
+	/*
+	 * io port are tight, don't try extra
+	 * or if reach the limit, don't want to try more
+	 */
+	failed_type &= type_mask;
+	if ((failed_type == IORESOURCE_IO) || (tried_times >= pci_try_num)) {
+		free_failed_list(&head);
+		goto enable_and_dump;
+	}
+
+	printk(KERN_DEBUG "PCI: No. %d try to assign unassigned res\n",
+			 tried_times + 1);
+
+	/* third times and later will not check if it is leaf */
+	if ((tried_times + 1) > 2)
+		rel_type = whole_subtree;
+
+	/*
+	 * Try to release leaf bridge's resources that doesn't fit resource of
+	 * child device under that bridge
+	 */
+	for (list = head.next; list;) {
+		bus = list->dev->bus;
+		pci_bus_release_bridge_resources(bus, list->flags & type_mask,
+						  rel_type);
+		list = list->next;
+	}
+	/* retore size and flags */
+	for (list = head.next; list;) {
+		struct resource *res = list->res;
+
+		res->start = list->start;
+		res->end = list->end;
+		res->flags = list->flags;
+		if (list->dev->subordinate)
+			res->flags = 0;
+
+		list = list->next;
+	}
+	free_failed_list(&head);
+
+	goto again;
+
+enable_and_dump:
+	/* Depth last, update the hardware. */
+	list_for_each_entry(bus, &pci_root_buses, node) {
 		pci_enable_bridges(bus);
 	}
 
-- 
1.6.4.2