This patch enhances PCI probe logic to support PCI bus lock mechanism.
Signed-off-by: Jiang Liu <liuj97@xxxxxxxxx>
---
drivers/pci/probe.c | 65 +++++++++++++++++++++++++++++++++++++++------------
1 file changed, 50 insertions(+), 15 deletions(-)
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 1f64e8d..e6b40d0 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -460,6 +460,8 @@ static struct pci_bus * pci_alloc_bus(void)
b->max_bus_speed = PCI_SPEED_UNKNOWN;
b->cur_bus_speed = PCI_SPEED_UNKNOWN;
device_initialize(&b->dev);
+ atomic_set(&b->state,
+ PCI_BUS_STATE_INITIALIZED | PCI_BUS_STATE_LOCK);
}
return b;
}
@@ -753,14 +755,21 @@ int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max,
* However, we continue to descend down the hierarchy and
* scan remaining child buses.
*/
- child = pci_find_bus(pci_domain_nr(bus), secondary);
- if (!child) {
+ child = __pci_get_and_lock_bus(pci_domain_nr(bus), secondary,
+ PCI_BUS_STATE_MASK);
+ if (child) {
+ if (pci_bus_get_state(child) > PCI_BUS_STATE_WORKING) {
+ pci_unlock_and_put_bus(child);
+ goto out;
+ }
+ } else {
child = pci_add_new_bus(bus, dev, secondary);
if (!child)
goto out;
child->primary = primary;
pci_bus_insert_busn_res(child, secondary, subordinate);
child->bridge_ctl = bctl;
+ pci_bus_get(child);
}
cmax = pci_scan_child_bus(child);
@@ -792,12 +801,19 @@ int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max,
/* 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_get_and_lock_bus(pci_domain_nr(bus), secondary,
+ PCI_BUS_STATE_MASK);
+ if (child) {
+ if (pci_bus_get_state(child) > PCI_BUS_STATE_WORKING) {
+ pci_unlock_and_put_bus(child);
+ goto out;
+ }
+ } else {
child = pci_add_new_bus(bus, dev, ++max);
if (!child)
goto out;
pci_bus_insert_busn_res(child, max, 0xff);
+ pci_bus_get(child);
}
buses = (buses & 0xff000000)
| ((unsigned int)(child->primary) << 0)
@@ -896,6 +912,8 @@ int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max,
bus = bus->parent;
}
+ pci_unlock_and_put_bus(child);
+
out:
pci_write_config_word(dev, PCI_BRIDGE_CONTROL, bctl);
@@ -1605,11 +1623,14 @@ unsigned int __devinit pci_scan_child_bus(struct pci_bus *bus)
* After performing arch-dependent fixup of the bus, look behind
* all PCI-to-PCI bridges on this bus.
*/
- if (!bus->is_added) {
+ if (pci_bus_get_state(bus) < PCI_BUS_STATE_WORKING) {
dev_dbg(&bus->dev, "fixups for bus\n");
pcibios_fixup_bus(bus);
- if (pci_is_root_bus(bus))
+ if (pci_is_root_bus(bus)) {
+ pci_bus_change_state(bus, PCI_BUS_STATE_REGISTERED,
+ PCI_BUS_STATE_WORKING, false);
bus->is_added = 1;
+ }
}
for (pass=0; pass < 2; pass++)
@@ -1630,6 +1651,11 @@ unsigned int __devinit pci_scan_child_bus(struct pci_bus *bus)
return max;
}
+/*
+ * Create a PCI root bus and return with the new root bus locked.
+ * Caller needs to call pci_bus_unlock() to unlock the new root bus after
+ * scanning and configuring children under the new root bus.
+ */
struct pci_bus *pci_create_root_bus(struct device *parent, int bus,
struct pci_ops *ops, void *sysdata, struct list_head *resources)
{
@@ -1716,6 +1742,9 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus,
list_add_tail(&b->node, &pci_root_buses);
up_write(&pci_bus_sem);
+ pci_bus_change_state(b, PCI_BUS_STATE_INITIALIZED,
+ PCI_BUS_STATE_REGISTERED, false);
+
return b;
class_dev_reg_err:
@@ -1724,7 +1753,7 @@ class_dev_reg_err:
bridge_dev_reg_err:
kfree(bridge);
err_out:
- kfree(b);
+ pci_unlock_and_put_bus(b);
return NULL;
}
@@ -1827,6 +1856,8 @@ struct pci_bus * __devinit pci_scan_root_bus(struct device *parent, int bus,
pci_bus_update_busn_res_end(b, max);
pci_bus_add_devices(b);
+ pci_bus_unlock(b);
+
return b;
}
EXPORT_SYMBOL(pci_scan_root_bus);
@@ -1842,10 +1873,12 @@ struct pci_bus * __devinit pci_scan_bus_parented(struct device *parent,
pci_add_resource(&resources, &iomem_resource);
pci_add_resource(&resources, &busn_resource);
b = pci_create_root_bus(parent, bus, ops, sysdata, &resources);
- if (b)
+ if (b) {
pci_scan_child_bus(b);
- else
+ pci_bus_unlock(b);
+ } else {
pci_free_resource_list(&resources);
+ }
return b;
}
EXPORT_SYMBOL(pci_scan_bus_parented);
@@ -1863,6 +1896,7 @@ struct pci_bus * __devinit pci_scan_bus(int bus, struct pci_ops *ops,
if (b) {
pci_scan_child_bus(b);
pci_bus_add_devices(b);
+ pci_bus_unlock(b);
} else {
pci_free_resource_list(&resources);
}
@@ -1884,14 +1918,15 @@ EXPORT_SYMBOL(pci_scan_bus);
*/
unsigned int __ref pci_rescan_bus_bridge_resize(struct pci_dev *bridge)
{
- unsigned int max;
+ unsigned int max = -1;
struct pci_bus *bus = bridge->subordinate;
- max = pci_scan_child_bus(bus);
-
- pci_assign_unassigned_bridge_resources(bridge);
-
- pci_bus_add_devices(bus);
+ if (pci_bus_lock_states(bus, PCI_BUS_STATE_WORKING) > 0) {
+ max = pci_scan_child_bus(bus);
+ pci_assign_unassigned_bridge_resources(bridge);
+ pci_bus_add_devices(bus);
+ pci_bus_unlock(bus);
+ }
return max;
}
--
1.7.9.5
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