When the movable BARs feature is enabled and a rescan has been requested,
release all the bridge windows and recalculate them from scratch, taking
into account all kinds for BARs: immovable+fixed, movable, new.
Comparing to simply trying to expand bridge windows, this also employs the
PCI ability to shuffle BARs within a bridge, increasing the chances to find
a memory space to fit BARs for newly hotplugged devices, especially if no
(not enough) gaps were reserved by the BIOS/bootloader/firmware.
The last step of writing the recalculated windows to the bridges is done
by the new pci_setup_bridges() function.
Signed-off-by: Sergei Miroshnichenko <s.miroshnichenko@xxxxxxxxx>
---
drivers/pci/pci.h | 1 +
drivers/pci/probe.c | 22 ++++++++++++++++++++++
drivers/pci/setup-bus.c | 16 ++++++++++++++++
3 files changed, 39 insertions(+)
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index ce8c53ca7a1e..fe995993b481 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -283,6 +283,7 @@ void __pci_bus_assign_resources(const struct pci_bus *bus,
struct list_head *realloc_head,
struct list_head *fail_head);
bool pci_bus_clip_resource(struct pci_dev *dev, int idx);
+void pci_bus_release_root_bridge_resources(struct pci_bus *bus);
void pci_reassigndev_resource_alignment(struct pci_dev *dev);
void pci_disable_bridge_window(struct pci_dev *dev);
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 9b6d15587f5d..daaaebdfd4c4 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -3190,6 +3190,25 @@ static void pci_bus_rescan_done(struct pci_bus *bus)
pci_config_pm_runtime_put(bus->self);
}
+static void pci_setup_bridges(struct pci_bus *bus)
+{
+ struct pci_dev *dev;
+
+ list_for_each_entry(dev, &bus->devices, bus_list) {
+ struct pci_bus *child;
+
+ if (!pci_dev_is_added(dev))
+ continue;
+
+ child = dev->subordinate;
+ if (child)
+ pci_setup_bridges(child);
+ }
+
+ if (bus->self)
+ pci_setup_bridge(bus);
+}
+
/**
* pci_rescan_bus - Scan a PCI bus for devices
* @bus: PCI bus to scan
@@ -3211,8 +3230,11 @@ unsigned int pci_rescan_bus(struct pci_bus *bus)
pci_bus_rescan_prepare(root);
max = pci_scan_child_bus(root);
+
+ pci_bus_release_root_bridge_resources(root);
pci_assign_unassigned_root_bus_resources(root);
+ pci_setup_bridges(root);
pci_bus_rescan_done(root);
} else {
max = pci_scan_child_bus(bus);
diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index 2cf07003d5fc..7a9bf979908d 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -1654,6 +1654,22 @@ static void pci_bus_release_bridge_resources(struct pci_bus *bus,
pci_bridge_release_resources(bus, type);
}
+void pci_bus_release_root_bridge_resources(struct pci_bus *root_bus)
+{
+ int i;
+ struct resource *r;
+
+ pci_bus_release_bridge_resources(root_bus, IORESOURCE_IO, whole_subtree);
+ pci_bus_release_bridge_resources(root_bus, IORESOURCE_MEM, whole_subtree);
+ pci_bus_release_bridge_resources(root_bus,
+ IORESOURCE_MEM_64 | IORESOURCE_PREFETCH,
+ whole_subtree);
+
+ pci_bus_for_each_resource(root_bus, r, i) {
+ pci_release_child_resources(root_bus, r);
+ }
+}
+
static void pci_bus_dump_res(struct pci_bus *bus)
{
struct resource *res;
--
2.24.1
