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authorKeith Busch <keith.busch@intel.com>2016-07-21 21:40:28 -0600
committerBjorn Helgaas <bhelgaas@google.com>2016-07-25 12:52:47 -0500
commite16b46605960bd071a3e26f316e0bb600ae91e37 (patch)
treecbddd9ca52a24d2a414c48e375d89f8c36596087 /drivers/pci
parentaf8c34ce6ae32addda3788d54a7e340cad22516b (diff)
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>
Diffstat (limited to 'drivers/pci')
-rw-r--r--drivers/pci/pci.c8
-rw-r--r--drivers/pci/probe.c9
2 files changed, 17 insertions, 0 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index c8b4dbdd1bdd..f18ea90cf91a 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -81,6 +81,9 @@ unsigned long pci_cardbus_mem_size = DEFAULT_CARDBUS_MEM_SIZE;
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 @@ static int __init pci_setup(char *str)
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)) {
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 8e3ef720997d..f680099c110d 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2077,6 +2077,15 @@ unsigned int pci_scan_child_bus(struct pci_bus *bus)
}
/*
+ * Make sure a hotplug bridge has at least the minimum requested
+ * number of buses.
+ */
+ if (bus->self && bus->self->is_hotplug_bridge && pci_hotplug_bus_size) {
+ if (max - bus->busn_res.start < pci_hotplug_bus_size - 1)
+ max = bus->busn_res.start + pci_hotplug_bus_size - 1;
+ }
+
+ /*
* We've scanned the bus and so we know all about what's on
* the other side of any bridges that may be on this bus plus
* any devices.