[PATCH 0/4] PCI: allocate pci bus num range for unassigned bridge busn

[PATCH 0/4] PCI: allocate pci bus num range for unassigned bridge busn

[Yinghai Lu]

5cb2147: PCI: Seperate child bus scanning to two passes overall
0cfebdb: PCI: kill pci_fixup_parent_subordinate_busnr()
cd03e86: PCI: Allocate bus range instead of use max blindly
e3edd5b: PCI: Add iobusn_resource and insert root bus range to that tree.

Set up iobusn_resource tree, and register bus number range to it.
Later when need to find bus range, will try to allocate from the tree

Need to test on arches other than x86. esp for ia64 and powerpc that support
  more than on peer root buses.

could be found at:
	git://git.kernel.org/pub/scm/linux/kernel/git/yinghai/linux-yinghai.git for-pci-busn-alloc

Thanks

Yinghai

 arch/ia64/pci/pci.c              |    2 +
 arch/powerpc/kernel/pci-common.c |    7 +-
 arch/x86/include/asm/topology.h  |    3 +-
 arch/x86/pci/acpi.c              |    8 +-
 arch/x86/pci/bus_numa.c          |    8 +-
 arch/x86/pci/common.c            |   11 +-
 drivers/parisc/dino.c            |    2 +
 drivers/parisc/lba_pci.c         |    3 +
 drivers/pci/probe.c              |  427 ++++++++++++++++++++++++++++++--------
 drivers/pci/remove.c             |    1 +
 include/linux/ioport.h           |    1 +
 include/linux/pci.h              |    8 +
 kernel/resource.c                |    8 +
 13 files changed, 395 insertions(+), 94 deletions(-)

[PATCH 1/4] PCI: Add iobusn_resource and insert root bus range to that tree.

[Yinghai Lu]

now only root bus number range is in that tree.

later every bus will have extra busn_res, and linked them toghter to iobusn_resource.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
---
 arch/ia64/pci/pci.c              |    2 +
 arch/powerpc/kernel/pci-common.c |    7 +++-
 arch/x86/include/asm/topology.h  |    3 +-
 arch/x86/pci/acpi.c              |    8 +++--
 arch/x86/pci/bus_numa.c          |    8 ++++-
 arch/x86/pci/common.c            |   11 ++++--
 drivers/parisc/dino.c            |    2 +
 drivers/parisc/lba_pci.c         |    3 ++
 drivers/pci/probe.c              |   74 +++++++++++++++++++++++++++++++++++--
 drivers/pci/remove.c             |    1 +
 include/linux/ioport.h           |    1 +
 include/linux/pci.h              |    8 ++++
 kernel/resource.c                |    8 ++++
 13 files changed, 122 insertions(+), 14 deletions(-)

diff --git a/arch/ia64/pci/pci.c b/arch/ia64/pci/pci.c
index f82f5d4..936b2f1 100644
--- a/arch/ia64/pci/pci.c
+++ b/arch/ia64/pci/pci.c
@@ -331,6 +331,7 @@ pci_acpi_scan_root(struct acpi_pci_root *root)
 	struct acpi_device *device = root->device;
 	int domain = root->segment;
 	int bus = root->secondary.start;
+	int busmax = root->secondary.end;
 	struct pci_controller *controller;
 	unsigned int windows = 0;
 	struct pci_root_info info;
@@ -384,6 +385,7 @@ pci_acpi_scan_root(struct acpi_pci_root *root)
 		return NULL;
 	}
 
+	pci_bus_insert_busn_res(pbus, busnum, busmax);
 	pbus->subordinate = pci_scan_child_bus(pbus);
 	return pbus;
 
diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
index cce98d7..501f29b 100644
--- a/arch/powerpc/kernel/pci-common.c
+++ b/arch/powerpc/kernel/pci-common.c
@@ -1732,6 +1732,8 @@ void __devinit pcibios_scan_phb(struct pci_controller *hose)
 	bus->secondary = hose->first_busno;
 	hose->bus = bus;
 
+	pci_bus_insert_busn_res(bus, hose->first_busno, hose->last_busno);
+
 	/* Get probe mode and perform scan */
 	mode = PCI_PROBE_NORMAL;
 	if (node && ppc_md.pci_probe_mode)
@@ -1742,8 +1744,11 @@ void __devinit pcibios_scan_phb(struct pci_controller *hose)
 		of_scan_bus(node, bus);
 	}
 
-	if (mode == PCI_PROBE_NORMAL)
+	if (mode == PCI_PROBE_NORMAL) {
+		pci_bus_update_busn_res_end(bus, 255);
 		hose->last_busno = bus->subordinate = pci_scan_child_bus(bus);
+		pci_bus_update_busn_res_end(bus, bus->subordinate);
+	}
 
 	/* Platform gets a chance to do some global fixups before
 	 * we proceed to resource allocation
diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h
index b9676ae..ad4060e 100644
--- a/arch/x86/include/asm/topology.h
+++ b/arch/x86/include/asm/topology.h
@@ -172,7 +172,8 @@ static inline void arch_fix_phys_package_id(int num, u32 slot)
 }
 
 struct pci_bus;
-void x86_pci_root_bus_resources(int bus, struct list_head *resources);
+void x86_pci_root_bus_resources(int bus, int *bus_max,
+				struct list_head *resources);
 
 #ifdef CONFIG_SMP
 #define mc_capable()	((boot_cpu_data.x86_max_cores > 1) && \
diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c
index a312e76..9d10fd8 100644
--- a/arch/x86/pci/acpi.c
+++ b/arch/x86/pci/acpi.c
@@ -348,6 +348,7 @@ struct pci_bus * __devinit pci_acpi_scan_root(struct acpi_pci_root *root)
 	struct acpi_device *device = root->device;
 	int domain = root->segment;
 	int busnum = root->secondary.start;
+	int busmax = root->secondary.end;
 	LIST_HEAD(resources);
 	struct pci_bus *bus;
 	struct pci_sysdata *sd;
@@ -405,12 +406,13 @@ struct pci_bus * __devinit pci_acpi_scan_root(struct acpi_pci_root *root)
 	} else {
 		get_current_resources(device, busnum, domain, &resources);
 		if (list_empty(&resources))
-			x86_pci_root_bus_resources(busnum, &resources);
+			x86_pci_root_bus_resources(busnum, &busmax, &resources);
 		bus = pci_create_root_bus(NULL, busnum, &pci_root_ops, sd,
 					  &resources);
-		if (bus)
+		if (bus) {
+			pci_bus_insert_busn_res(bus, busnum, busmax);
 			bus->subordinate = pci_scan_child_bus(bus);
-		else
+		} else
 			pci_free_resource_list(&resources);
 	}
 
diff --git a/arch/x86/pci/bus_numa.c b/arch/x86/pci/bus_numa.c
index fd3f655..5213cd8 100644
--- a/arch/x86/pci/bus_numa.c
+++ b/arch/x86/pci/bus_numa.c
@@ -7,7 +7,8 @@
 int pci_root_num;
 struct pci_root_info pci_root_info[PCI_ROOT_NR];
 
-void x86_pci_root_bus_resources(int bus, struct list_head *resources)
+void x86_pci_root_bus_resources(int bus, int *bus_max,
+				struct list_head *resources)
 {
 	int i;
 	int j;
@@ -28,6 +29,7 @@ void x86_pci_root_bus_resources(int bus, struct list_head *resources)
 	       bus);
 
 	info = &pci_root_info[i];
+	*bus_max = info->bus_max;
 	for (j = 0; j < info->res_num; j++) {
 		struct resource *res;
 		struct resource *root;
@@ -51,6 +53,10 @@ default_resources:
 	printk(KERN_DEBUG "PCI: root bus %02x: using default resources\n", bus);
 	pci_add_resource(resources, &ioport_resource);
 	pci_add_resource(resources, &iomem_resource);
+	if (!bus)
+		*bus_max = 0xff;
+	else if (!*bus_max)
+		*bus_max = bus;
 }
 
 void __devinit update_res(struct pci_root_info *info, resource_size_t start,
diff --git a/arch/x86/pci/common.c b/arch/x86/pci/common.c
index 323481e..ce0aefc 100644
--- a/arch/x86/pci/common.c
+++ b/arch/x86/pci/common.c
@@ -433,6 +433,7 @@ struct pci_bus * __devinit pcibios_scan_root(int busnum)
 	LIST_HEAD(resources);
 	struct pci_bus *bus = NULL;
 	struct pci_sysdata *sd;
+	int bus_max;
 
 	while ((bus = pci_find_next_bus(bus)) != NULL) {
 		if (bus->number == busnum) {
@@ -454,8 +455,9 @@ struct pci_bus * __devinit pcibios_scan_root(int busnum)
 	sd->node = get_mp_bus_to_node(busnum);
 
 	printk(KERN_DEBUG "PCI: Probing PCI hardware (bus %02x)\n", busnum);
-	x86_pci_root_bus_resources(busnum, &resources);
-	bus = pci_scan_root_bus(NULL, busnum, &pci_root_ops, sd, &resources);
+	x86_pci_root_bus_resources(busnum, &bus_max, &resources);
+	bus = pci_scan_root_bus_max(NULL, busnum, bus_max, &pci_root_ops, sd,
+				&resources);
 	if (!bus) {
 		pci_free_resource_list(&resources);
 		kfree(sd);
@@ -643,6 +645,7 @@ struct pci_bus * __devinit pci_scan_bus_on_node(int busno, struct pci_ops *ops,
 	LIST_HEAD(resources);
 	struct pci_bus *bus = NULL;
 	struct pci_sysdata *sd;
+	int bus_max;
 
 	/*
 	 * Allocate per-root-bus (not per bus) arch-specific data.
@@ -655,8 +658,8 @@ struct pci_bus * __devinit pci_scan_bus_on_node(int busno, struct pci_ops *ops,
 		return NULL;
 	}
 	sd->node = node;
-	x86_pci_root_bus_resources(busno, &resources);
-	bus = pci_scan_root_bus(NULL, busno, ops, sd, &resources);
+	x86_pci_root_bus_resources(busno, &bus_max, &resources);
+	bus = pci_scan_root_bus_max(NULL, busno, bus_max, ops, sd, &resources);
 	if (!bus) {
 		pci_free_resource_list(&resources);
 		kfree(sd);
diff --git a/drivers/parisc/dino.c b/drivers/parisc/dino.c
index 7ff10c1..3f2e203 100644
--- a/drivers/parisc/dino.c
+++ b/drivers/parisc/dino.c
@@ -1014,7 +1014,9 @@ static int __init dino_probe(struct parisc_device *dev)
 		return 0;
 	}
 
+	pci_bus_insert_busn_res(bus, dino_current_bus, 255);
 	bus->subordinate = pci_scan_child_bus(bus);
+	pci_bus_update_busn_res_end(bus, bus->subordinate);
 
 	/* This code *depends* on scanning being single threaded
 	 * if it isn't, this global bus number count will fail
diff --git a/drivers/parisc/lba_pci.c b/drivers/parisc/lba_pci.c
index d5f3d75..b58bf8b 100644
--- a/drivers/parisc/lba_pci.c
+++ b/drivers/parisc/lba_pci.c
@@ -1531,6 +1531,9 @@ lba_driver_probe(struct parisc_device *dev)
 		return 0;
 	}
 
+	pci_bus_insert_busn_res(lba_bus, lba_dev->hba.bus_num.start,
+				lba_dev->hba.bus_num.end);
+
 	lba_bus->subordinate = pci_scan_child_bus(lba_bus);
 
 	/* This is in lieu of calling pci_assign_unassigned_resources() */
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 7cc9e2f..f327c04 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1608,8 +1608,53 @@ err_out:
 	return NULL;
 }
 
-struct pci_bus * __devinit pci_scan_root_bus(struct device *parent, int bus,
-		struct pci_ops *ops, void *sysdata, struct list_head *resources)
+void pci_bus_insert_busn_res(struct pci_bus *b, int bus, int bus_max)
+{
+	struct resource *res = &b->busn_res;
+	struct resource *parent_res = &iobusn_resource;
+	int ret;
+
+	res->start = (pci_domain_nr(b) << 8) | bus;
+	res->end = (pci_domain_nr(b) << 8) | bus_max;
+	res->flags = IORESOURCE_BUS;
+
+	if (!pci_is_root_bus(b))
+		parent_res = &b->parent->busn_res;
+
+	ret = insert_resource(parent_res, res);
+
+	dev_printk(KERN_DEBUG, &b->dev,
+	 "busn_res: %06llx-%06llx %s inserted under %06llx-%06llx\n",
+			(unsigned long long)res->start,
+			(unsigned long long)res->end,
+			 ret ? "can not be" : "is",
+			(unsigned long long)parent_res->start,
+			(unsigned long long)parent_res->end);
+}
+
+void pci_bus_update_busn_res_end(struct pci_bus *b, int bus_max)
+{
+	struct resource *res = &b->busn_res;
+	unsigned long long old_end = res->end;
+
+	res->end &= ~0xff;
+	res->end |= bus_max;
+	dev_printk(KERN_DEBUG, &b->dev,
+		 "busn_res: %06llx-%06llx end updated to %06llx-%06llx\n",
+			(unsigned long long)res->start,
+			old_end,
+			(unsigned long long)res->start,
+			(unsigned long long)res->end);
+}
+
+void pci_bus_release_busn_res(struct pci_bus *b)
+{
+	release_resource(&b->busn_res);
+}
+
+struct pci_bus * __devinit pci_scan_root_bus_max(struct device *parent, int bus,
+		int bus_max, struct pci_ops *ops, void *sysdata,
+		struct list_head *resources)
 {
 	struct pci_bus *b;
 
@@ -1617,10 +1662,26 @@ struct pci_bus * __devinit pci_scan_root_bus(struct device *parent, int bus,
 	if (!b)
 		return NULL;
 
+	pci_bus_insert_busn_res(b, bus, bus_max);
 	b->subordinate = pci_scan_child_bus(b);
 	pci_bus_add_devices(b);
 	return b;
 }
+EXPORT_SYMBOL(pci_scan_root_bus_max);
+
+struct pci_bus * __devinit pci_scan_root_bus(struct device *parent, int bus,
+		struct pci_ops *ops, void *sysdata,
+		struct list_head *resources)
+{
+	struct pci_bus *b;
+
+	b = pci_scan_root_bus_max(parent, bus, 255, ops, sysdata, resources);
+
+	if (b)
+		pci_bus_update_busn_res_end(b, b->subordinate);
+
+	return b;
+}
 EXPORT_SYMBOL(pci_scan_root_bus);
 
 /* Deprecated; use pci_scan_root_bus() instead */
@@ -1633,9 +1694,11 @@ struct pci_bus * __devinit pci_scan_bus_parented(struct device *parent,
 	pci_add_resource(&resources, &ioport_resource);
 	pci_add_resource(&resources, &iomem_resource);
 	b = pci_create_root_bus(parent, bus, ops, sysdata, &resources);
-	if (b)
+	if (b) {
+		pci_bus_insert_busn_res(b, bus, 255);
 		b->subordinate = pci_scan_child_bus(b);
-	else
+		pci_bus_update_busn_res_end(b, b->subordinate);
+	} else
 		pci_free_resource_list(&resources);
 	return b;
 }
@@ -1651,7 +1714,10 @@ struct pci_bus * __devinit pci_scan_bus(int bus, struct pci_ops *ops,
 	pci_add_resource(&resources, &iomem_resource);
 	b = pci_create_root_bus(NULL, bus, ops, sysdata, &resources);
 	if (b) {
+		pci_bus_insert_busn_res(b, bus, 255);
 		b->subordinate = pci_scan_child_bus(b);
+		pci_bus_update_busn_res_end(b, b->subordinate);
+
 		pci_bus_add_devices(b);
 	} else {
 		pci_free_resource_list(&resources);
diff --git a/drivers/pci/remove.c b/drivers/pci/remove.c
index 6def362..391e276 100644
--- a/drivers/pci/remove.c
+++ b/drivers/pci/remove.c
@@ -68,6 +68,7 @@ void pci_remove_bus(struct pci_bus *pci_bus)
 
 	down_write(&pci_bus_sem);
 	list_del(&pci_bus->node);
+	pci_bus_release_busn_res(pci_bus);
 	up_write(&pci_bus_sem);
 	if (!pci_bus->is_added)
 		return;
diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index 9d57a71..c96781c 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -142,6 +142,7 @@ struct resource_list {
 /* PC/ISA/whatever - the normal PC address spaces: IO and memory */
 extern struct resource ioport_resource;
 extern struct resource iomem_resource;
+extern struct resource iobusn_resource;
 
 extern struct resource *request_resource_conflict(struct resource *root, struct resource *new);
 extern int request_resource(struct resource *root, struct resource *new);
diff --git a/include/linux/pci.h b/include/linux/pci.h
index a16b1df..06507cc 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -420,6 +420,7 @@ struct pci_bus {
 	struct list_head slots;		/* list of slots on this bus */
 	struct resource *resource[PCI_BRIDGE_RESOURCE_NUM];
 	struct list_head resources;	/* address space routed to this bus */
+	struct resource busn_res;	/* track registered bus num range */
 
 	struct pci_ops	*ops;		/* configuration access functions */
 	void		*sysdata;	/* hook for sys-specific extension */
@@ -665,6 +666,13 @@ struct pci_bus *pci_scan_bus(int bus, struct pci_ops *ops, void *sysdata);
 struct pci_bus *pci_create_root_bus(struct device *parent, int bus,
 				    struct pci_ops *ops, void *sysdata,
 				    struct list_head *resources);
+void pci_bus_insert_busn_res(struct pci_bus *b, int bus, int busmax);
+void pci_bus_update_busn_res_end(struct pci_bus *b, int busmax);
+void pci_bus_release_busn_res(struct pci_bus *b);
+struct pci_bus * __devinit pci_scan_root_bus_max(struct device *parent, int bus,
+					     int busmax, struct pci_ops *ops,
+					     void *sysdata,
+					     struct list_head *resources);
 struct pci_bus * __devinit pci_scan_root_bus(struct device *parent, int bus,
 					     struct pci_ops *ops, void *sysdata,
 					     struct list_head *resources);
diff --git a/kernel/resource.c b/kernel/resource.c
index 7640b3a..53b42f0 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -38,6 +38,14 @@ struct resource iomem_resource = {
 };
 EXPORT_SYMBOL(iomem_resource);
 
+struct resource iobusn_resource = {
+	.name	= "PCI busn",
+	.start	= 0,
+	.end	= 0xffffff,
+	.flags	= IORESOURCE_BUS,
+};
+EXPORT_SYMBOL(iobusn_resource);
+
 /* constraints to be met while allocating resources */
 struct resource_constraint {
 	resource_size_t min, max, align;
-- 
1.7.7

[PATCH 2/4] PCI: Allocate bus range instead of use max blindly

[Yinghai Lu]

every bus have extra busn_res, and linked them toghter to iobusn_resource.

when need to find usabled bus number range, try allocate from
iobusn_resource tree.

-v3: support extend buses top.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
---
 drivers/pci/probe.c |  276 ++++++++++++++++++++++++++++++++++++++++++++-------
 1 files changed, 239 insertions(+), 37 deletions(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index f327c04..f58164d 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -624,6 +624,200 @@ static void pci_fixup_parent_subordinate_busnr(struct pci_bus *child, int max)
 	}
 }
 
+static void __devinit pci_bus_extend_top(struct pci_bus *parent,
+		 resource_size_t size, struct resource *parent_res)
+{
+	struct resource *res;
+
+	if (!size)
+		return;
+
+	while (parent) {
+		res = &parent->busn_res;
+		if (res == parent_res)
+			break;
+		res->end += size;
+		parent->subordinate += size;
+		pci_write_config_byte(parent->self, PCI_SUBORDINATE_BUS,
+					 parent->subordinate);
+		dev_printk(KERN_DEBUG, &parent->dev,
+				"busn_res: extended %02llx to %06llx-%06llx\n",
+				(unsigned long long)size,
+				(unsigned long long)res->start,
+				(unsigned long long)res->end);
+		parent = parent->parent;
+	}
+}
+
+static void __devinit pci_bus_shrink_top(struct pci_bus *parent,
+		 resource_size_t size, struct resource *parent_res)
+{
+	struct resource *res;
+
+	if (!size)
+		return;
+
+	while (parent) {
+		res = &parent->busn_res;
+		if (res == parent_res)
+			break;
+		res->end -= size;
+		parent->subordinate -= size;
+		pci_write_config_byte(parent->self, PCI_SUBORDINATE_BUS,
+					 parent->subordinate);
+		dev_printk(KERN_DEBUG, &parent->dev,
+				"busn_res: shrunk %02llx to %06llx-%06llx\n",
+				(unsigned long long)size,
+				(unsigned long long)res->start,
+				(unsigned long long)res->end);
+		parent = parent->parent;
+	}
+}
+
+static resource_size_t __devinit find_res_top_free_size(struct resource *res)
+{
+	int ret = -ENOMEM;
+	resource_size_t n_size;
+	struct resource tmp_res;
+
+	/*
+	 *   find out number below res->end, that we can use at first
+	 *	res->start can not be used.
+	 */
+	n_size = resource_size(res) - 1;
+	memset(&tmp_res, 0, sizeof(struct resource));
+	while (n_size > 0) {
+		ret = allocate_resource(res, &tmp_res, n_size,
+			res->end - n_size + 1, res->end,
+			1, NULL, NULL);
+		if (ret == 0) {
+			/* release busn_res */
+			release_resource(&tmp_res);
+			break;
+		}
+		n_size--;
+	}
+
+	return n_size;
+}
+
+static int __devinit pci_bridge_probe_busn_res(struct pci_bus *bus,
+			 struct pci_dev *dev, struct resource *busn_res,
+			 resource_size_t needed_size, struct resource **p)
+{
+	int ret = -ENOMEM;
+	resource_size_t n_size;
+	struct pci_bus *parent;
+	struct resource *parent_res;
+	resource_size_t tmp = bus->busn_res.end + 1;
+	int free_sz = -1;
+
+	parent_res = NULL;
+
+again:
+	/*
+	 * find bigest range in bus->busn_res that we can use in the middle
+	 *  and we can not use bus->busn_res.start.
+	 */
+	n_size = resource_size(&bus->busn_res) - 1;
+	memset(busn_res, 0, sizeof(struct resource));
+	dev_printk(KERN_DEBUG, &dev->dev,
+			"find free busn in busn_res: %06llx-%06llx\n",
+			(unsigned long long)bus->busn_res.start,
+			(unsigned long long)bus->busn_res.end);
+	while (n_size >= needed_size) {
+		ret = allocate_resource(&bus->busn_res, busn_res, n_size,
+				bus->busn_res.start + 1, bus->busn_res.end,
+				1, NULL, NULL);
+		if (ret == 0) {
+			/* release res */
+			release_resource(busn_res);
+
+			return ret;
+		}
+		n_size--;
+	}
+
+	/* try extend the top of parent buss */
+	if (free_sz < 0) {
+		free_sz = find_res_top_free_size(&bus->busn_res);
+		dev_printk(KERN_DEBUG, &dev->dev,
+			"found free busn %d in busn_res: %06llx-%06llx top\n",
+				free_sz,
+				(unsigned long long)bus->busn_res.start,
+				(unsigned long long)bus->busn_res.end);
+	}
+	n_size = free_sz;
+
+	/* check if extend could cross domain boundary */
+	if ((bus->busn_res.end & 0xff) == 0xff)
+		goto reduce_needed_size;
+	if ((0x100 - (tmp & 0xff)) < (needed_size - n_size))
+		goto reduce_needed_size;
+
+	/* find exteded range */
+	memset(busn_res, 0, sizeof(struct resource));
+	parent = bus->parent;
+	while (parent) {
+		ret = allocate_resource(&parent->busn_res, busn_res,
+			 needed_size - n_size,
+			 tmp, tmp + needed_size - n_size - 1,
+			 1, NULL, NULL);
+		if (ret == 0)
+			break;
+		parent = parent->parent;
+	}
+
+reduce_needed_size:
+	if (ret != 0) {
+		needed_size--;
+		if (!needed_size)
+			return ret;
+
+		goto again;
+	}
+
+	/* save parent_res, we need it as stopper later */
+	parent_res = busn_res->parent;
+	/* release busn_res */
+	release_resource(busn_res);
+	busn_res->start -= n_size;
+
+	/* extend parent bus top*/
+	pci_bus_extend_top(bus, needed_size - n_size, parent_res);
+
+	*p = parent_res;
+
+	return ret;
+}
+
+static int __devinit pci_bridge_check_busn_res(struct pci_bus *bus,
+				struct pci_dev *dev,
+				int secondary, int subordinate)
+{
+	int broken = 0;
+
+	struct resource busn_res;
+	int ret;
+
+	memset(&busn_res, 0, sizeof(struct resource));
+	dev_printk(KERN_DEBUG, &dev->dev,
+		 "check if busn %02x-%02x is in busn_res: %06llx-%06llx\n",
+		 secondary, subordinate,
+		 (unsigned long long)bus->busn_res.start,
+		 (unsigned long long)bus->busn_res.end);
+	ret = allocate_resource(&bus->busn_res, &busn_res,
+			 (subordinate - secondary + 1),
+			 (pci_domain_nr(bus)<<8) | secondary,
+			 (pci_domain_nr(bus)<<8) | subordinate,
+			 1, NULL, NULL);
+	if (ret)
+		broken = 1;
+	else
+		release_resource(&busn_res);
+
+	return broken;
+}
 /*
  * If it's a bridge, configure it and scan the bus behind it.
  * For CardBus bridges, we don't scan behind as the devices will
@@ -638,10 +832,11 @@ int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max,
 {
 	struct pci_bus *child;
 	int is_cardbus = (dev->hdr_type == PCI_HEADER_TYPE_CARDBUS);
-	u32 buses, i, j = 0;
+	u32 buses;
 	u16 bctl;
 	u8 primary, secondary, subordinate;
 	int broken = 0;
+	struct resource *parent_res = NULL;
 
 	pci_read_config_dword(dev, PCI_PRIMARY_BUS, &buses);
 	primary = buses & 0xFF;
@@ -653,10 +848,16 @@ int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max,
 
 	/* Check if setup is sensible at all */
 	if (!pass &&
-	    (primary != bus->number || secondary <= bus->number)) {
-		dev_dbg(&dev->dev, "bus configuration invalid, reconfiguring\n");
+	    (primary != bus->number || secondary <= bus->number))
 		broken = 1;
-	}
+
+	/* more strict checking */
+	if (!pass && !broken)
+		broken = pci_bridge_check_busn_res(bus, dev,
+						   secondary, subordinate);
+
+	if (broken)
+		dev_dbg(&dev->dev, "bus configuration invalid, reconfiguring\n");
 
 	/* Disable MasterAbortMode during probing to avoid reporting
 	   of bus errors (in some architectures) */ 
@@ -689,6 +890,8 @@ int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max,
 			child->primary = primary;
 			child->subordinate = subordinate;
 			child->bridge_ctl = bctl;
+
+			pci_bus_insert_busn_res(child, secondary, subordinate);
 		}
 
 		cmax = pci_scan_child_bus(child);
@@ -701,6 +904,11 @@ int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max,
 		 * We need to assign a number to this bus which we always
 		 * do in the second pass.
 		 */
+		resource_size_t shrink_size;
+		struct resource busn_res;
+		int ret = -ENOMEM;
+		int old_max = max;
+
 		if (!pass) {
 			if (pcibios_assign_all_busses() || broken)
 				/* Temporarily disable forwarding of the
@@ -717,20 +925,28 @@ int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max,
 		/* Clear errors */
 		pci_write_config_word(dev, PCI_STATUS, 0xffff);
 
-		/* Prevent assigning a bus number that already exists.
-		 * This can happen when a bridge is hot-plugged, so in
-		 * this case we only re-scan this bus. */
-		child = pci_find_bus(pci_domain_nr(bus), max+1);
-		if (!child) {
-			child = pci_add_new_bus(bus, dev, ++max);
-			if (!child)
-				goto out;
-		}
+		ret = pci_bridge_probe_busn_res(bus, dev, &busn_res,
+				is_cardbus ? (CARDBUS_RESERVE_BUSNR + 1) : 8,
+				&parent_res);
+
+		if (ret != 0)
+			goto out;
+
+		child = pci_add_new_bus(bus, dev, busn_res.start & 0xff);
+		if (!child)
+			goto out;
+
+		child->subordinate = busn_res.end & 0xff;
+		pci_bus_insert_busn_res(child, busn_res.start & 0xff,
+					busn_res.end & 0xff);
+
 		buses = (buses & 0xff000000)
 		      | ((unsigned int)(child->primary)     <<  0)
 		      | ((unsigned int)(child->secondary)   <<  8)
 		      | ((unsigned int)(child->subordinate) << 16);
 
+		max = child->subordinate;
+
 		/*
 		 * yenta.c forces a secondary latency timer of 176.
 		 * Copy that behaviour here.
@@ -761,43 +977,29 @@ int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max,
 			 * the real value of max.
 			 */
 			pci_fixup_parent_subordinate_busnr(child, max);
+
 		} else {
 			/*
 			 * For CardBus bridges, we leave 4 bus numbers
 			 * as cards with a PCI-to-PCI bridge can be
 			 * inserted later.
 			 */
-			for (i=0; i<CARDBUS_RESERVE_BUSNR; i++) {
-				struct pci_bus *parent = bus;
-				if (pci_find_bus(pci_domain_nr(bus),
-							max+i+1))
-					break;
-				while (parent->parent) {
-					if ((!pcibios_assign_all_busses()) &&
-					    (parent->subordinate > max) &&
-					    (parent->subordinate <= max+i)) {
-						j = 1;
-					}
-					parent = parent->parent;
-				}
-				if (j) {
-					/*
-					 * Often, there are two cardbus bridges
-					 * -- try to leave one valid bus number
-					 * for each one.
-					 */
-					i /= 2;
-					break;
-				}
-			}
-			max += i;
 			pci_fixup_parent_subordinate_busnr(child, max);
 		}
 		/*
 		 * Set the subordinate bus number to its real value.
 		 */
+		shrink_size = child->subordinate - max;
 		child->subordinate = max;
 		pci_write_config_byte(dev, PCI_SUBORDINATE_BUS, max);
+		pci_bus_update_busn_res_end(child, max);
+
+		/* shrink some back, if we extend top before */
+		if (!is_cardbus &&  (shrink_size > 0) && parent_res)
+			pci_bus_shrink_top(bus, shrink_size, parent_res);
+
+		if (old_max > max)
+			max = old_max;
 	}
 
 	sprintf(child->name,
-- 
1.7.7

[PATCH 3/4] PCI: kill pci_fixup_parent_subordinate_busnr()

[Yinghai Lu]

Now we can safely extend parent top and shrink them according iobusn_resource tree.

Don't need that any more.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
---
 drivers/pci/probe.c |   45 +++++++++------------------------------------
 1 files changed, 9 insertions(+), 36 deletions(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index f58164d..d078a58 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -608,22 +608,6 @@ struct pci_bus *__ref pci_add_new_bus(struct pci_bus *parent, struct pci_dev *de
 	return child;
 }
 
-static void pci_fixup_parent_subordinate_busnr(struct pci_bus *child, int max)
-{
-	struct pci_bus *parent = child->parent;
-
-	/* Attempts to fix that up are really dangerous unless
-	   we're going to re-assign all bus numbers. */
-	if (!pcibios_assign_all_busses())
-		return;
-
-	while (parent->parent && parent->subordinate < max) {
-		parent->subordinate = max;
-		pci_write_config_byte(parent->self, PCI_SUBORDINATE_BUS, max);
-		parent = parent->parent;
-	}
-}
-
 static void __devinit pci_bus_extend_top(struct pci_bus *parent,
 		 resource_size_t size, struct resource *parent_res)
 {
@@ -925,6 +909,13 @@ int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max,
 		/* Clear errors */
 		pci_write_config_word(dev, PCI_STATUS, 0xffff);
 
+		/*
+		 * For CardBus bridges, we leave 4 bus numbers
+		 * as cards with a PCI-to-PCI bridge can be
+		 * inserted later.
+		 * other just allocate 8 bus to avoid we fall into
+		 *  small hole in the middle.
+		 */
 		ret = pci_bridge_probe_busn_res(bus, dev, &busn_res,
 				is_cardbus ? (CARDBUS_RESERVE_BUSNR + 1) : 8,
 				&parent_res);
@@ -963,29 +954,11 @@ int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max,
 
 		if (!is_cardbus) {
 			child->bridge_ctl = bctl;
-			/*
-			 * Adjust subordinate busnr in parent buses.
-			 * We do this before scanning for children because
-			 * some devices may not be detected if the bios
-			 * was lazy.
-			 */
-			pci_fixup_parent_subordinate_busnr(child, max);
+
 			/* Now we can scan all subordinate buses... */
 			max = pci_scan_child_bus(child);
-			/*
-			 * now fix it up again since we have found
-			 * the real value of max.
-			 */
-			pci_fixup_parent_subordinate_busnr(child, max);
-
-		} else {
-			/*
-			 * For CardBus bridges, we leave 4 bus numbers
-			 * as cards with a PCI-to-PCI bridge can be
-			 * inserted later.
-			 */
-			pci_fixup_parent_subordinate_busnr(child, max);
 		}
+
 		/*
 		 * Set the subordinate bus number to its real value.
 		 */
-- 
1.7.7

[PATCH 4/4] PCI: Seperate child bus scanning to two passes overall

[Yinghai Lu]

In extreme case: Two bridges are properly setup.
       bridge A
               bridge AA
               bridge AB
       bridge B
	       bridge BA
	       bridge BB
   but AA, AB are not setup properly.
   bridge A has small range, and bridge AB could need more, when do the
       first pass0 for bridge A, it will do pass0 and pass1 for AA and AB,
	during that process, it will extend range of A for AB blindly.
	because bridge B is not registered yet.
       that could overlap range that is used by bridge B.

Right way should be:
       do pass0 for all good bridges at first.
So we could do pass0 for bridge B before pass1 for bridge AB.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
---
 drivers/pci/probe.c |   50 ++++++++++++++++++++++++++++++++++----------------
 1 files changed, 34 insertions(+), 16 deletions(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index d078a58..91406cd 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -802,6 +802,9 @@ static int __devinit pci_bridge_check_busn_res(struct pci_bus *bus,
 
 	return broken;
 }
+
+static unsigned int __devinit __pci_scan_child_bus(struct pci_bus *bus,
+						 int pass);
 /*
  * If it's a bridge, configure it and scan the bus behind it.
  * For CardBus bridges, we don't scan behind as the devices will
@@ -853,11 +856,10 @@ int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max,
 	    !is_cardbus && !broken) {
 		unsigned int cmax;
 		/*
-		 * Bus already configured by firmware, process it in the first
-		 * pass and just note the configuration.
+		 * Bus already configured by firmware, still process it in two
+		 * passes in extreme case like two adjaced bridges have children
+		 * bridges that are not setup properly.
 		 */
-		if (pass)
-			goto out;
 
 		/*
 		 * If we already got to this bus through a different bridge,
@@ -878,7 +880,7 @@ int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max,
 			pci_bus_insert_busn_res(child, secondary, subordinate);
 		}
 
-		cmax = pci_scan_child_bus(child);
+		cmax = __pci_scan_child_bus(child, pass);
 		if (cmax > max)
 			max = cmax;
 		if (child->subordinate > max)
@@ -1654,12 +1656,13 @@ void pcie_bus_configure_settings(struct pci_bus *bus, u8 mpss)
 }
 EXPORT_SYMBOL_GPL(pcie_bus_configure_settings);
 
-unsigned int __devinit pci_scan_child_bus(struct pci_bus *bus)
+static unsigned int __devinit __pci_scan_child_bus(struct pci_bus *bus,
+						 int pass)
 {
-	unsigned int devfn, pass, max = bus->secondary;
+	unsigned int devfn, max = bus->secondary;
 	struct pci_dev *dev;
 
-	dev_dbg(&bus->dev, "scanning bus\n");
+	dev_dbg(&bus->dev, "scanning bus pass %d\n", pass);
 
 	/* Go find them, Rover! */
 	for (devfn = 0; devfn < 0x100; devfn += 8)
@@ -1673,18 +1676,16 @@ unsigned int __devinit pci_scan_child_bus(struct pci_bus *bus)
 	 * all PCI-to-PCI bridges on this bus.
 	 */
 	if (!bus->is_added) {
-		dev_dbg(&bus->dev, "fixups for bus\n");
+		dev_dbg(&bus->dev, "fixups for bus pass %d\n", pass);
 		pcibios_fixup_bus(bus);
 		if (pci_is_root_bus(bus))
 			bus->is_added = 1;
 	}
 
-	for (pass=0; pass < 2; pass++)
-		list_for_each_entry(dev, &bus->devices, bus_list) {
-			if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE ||
-			    dev->hdr_type == PCI_HEADER_TYPE_CARDBUS)
-				max = pci_scan_bridge(bus, dev, max, pass);
-		}
+	list_for_each_entry(dev, &bus->devices, bus_list)
+		if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE ||
+		    dev->hdr_type == PCI_HEADER_TYPE_CARDBUS)
+			max = pci_scan_bridge(bus, dev, max, pass);
 
 	/*
 	 * We've scanned the bus and so we know all about what's on
@@ -1693,7 +1694,24 @@ unsigned int __devinit pci_scan_child_bus(struct pci_bus *bus)
 	 *
 	 * Return how far we've got finding sub-buses.
 	 */
-	dev_dbg(&bus->dev, "bus scan returning with max=%02x\n", max);
+	dev_dbg(&bus->dev, "bus scan returning with max=%02x pass %d\n",
+			max, pass);
+
+	return max;
+}
+
+unsigned int __devinit pci_scan_child_bus(struct pci_bus *bus)
+{
+	int pass;
+	unsigned int max = 0, tmp;
+
+	for (pass = 0; pass < 2;  pass++) {
+		tmp = __pci_scan_child_bus(bus, pass);
+
+		if (tmp > max)
+			max = tmp;
+	}
+
 	return max;
 }
 
-- 
1.7.7

Re: [PATCH 1/4] PCI: Add iobusn_resource and insert root bus range to that tree.

[Jesse Barnes]

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On Mon, 23 Jan 2012 15:06:55 -0800
Yinghai Lu <yinghai@kernel.org> wrote:

> now only root bus number range is in that tree.
> 
> later every bus will have extra busn_res, and linked them toghter to iobusn_resource.
> 
> Signed-off-by: Yinghai Lu <yinghai@kernel.org>
> ---

This needs to be split into at least a few patches:
  - one to add the bus resource tracking infrastructure to the core
  - one to add tracking to the core
  - one patch per arch

and acks and tested-bys from the arch folks.

Thanks,
-- 
Jesse Barnes, Intel Open Source Technology Center

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