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| author | Keith Busch <keith.busch@intel.com> | 2016-07-21 21:40:28 -0600 |
|---|---|---|
| committer | Bjorn Helgaas <bhelgaas@google.com> | 2016-07-25 12:52:47 -0500 |
| commit | e16b46605960bd071a3e26f316e0bb600ae91e37 (patch) | |
| tree | cbddd9ca52a24d2a414c48e375d89f8c36596087 /drivers/pci | |
| parent | af8c34ce6ae32addda3788d54a7e340cad22516b (diff) | |
| download | lwn-e16b46605960bd071a3e26f316e0bb600ae91e37.tar.gz lwn-e16b46605960bd071a3e26f316e0bb600ae91e37.zip | |
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.c | 8 | ||||
| -rw-r--r-- | drivers/pci/probe.c | 9 |
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. |