PCI: Allow additional bus numbers for hotplug bridges
A user may hot add a switch requiring more than one bus to enumerate. This
previously required a system reboot if BIOS did not sufficiently pad the
bus resource, which they frequently don't do.
Add a kernel parameter so a user can specify the minimum number of bus
numbers to reserve for a hotplug bridge's subordinate buses so rebooting
won't be necessary.
The default is 1, which is equivalent to previous behavior.
Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index c8b4dbd..f18ea90 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -81,6 +81,9 @@
unsigned long pci_hotplug_io_size = DEFAULT_HOTPLUG_IO_SIZE;
unsigned long pci_hotplug_mem_size = DEFAULT_HOTPLUG_MEM_SIZE;
+#define DEFAULT_HOTPLUG_BUS_SIZE 1
+unsigned long pci_hotplug_bus_size = DEFAULT_HOTPLUG_BUS_SIZE;
+
enum pcie_bus_config_types pcie_bus_config = PCIE_BUS_DEFAULT;
/*
@@ -5021,6 +5024,11 @@
pci_hotplug_io_size = memparse(str + 9, &str);
} else if (!strncmp(str, "hpmemsize=", 10)) {
pci_hotplug_mem_size = memparse(str + 10, &str);
+ } else if (!strncmp(str, "hpbussize=", 10)) {
+ pci_hotplug_bus_size =
+ simple_strtoul(str + 10, &str, 0);
+ if (pci_hotplug_bus_size > 0xff)
+ pci_hotplug_bus_size = DEFAULT_HOTPLUG_BUS_SIZE;
} else if (!strncmp(str, "pcie_bus_tune_off", 17)) {
pcie_bus_config = PCIE_BUS_TUNE_OFF;
} else if (!strncmp(str, "pcie_bus_safe", 13)) {