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authorNicholas Johnson <nicholas.johnson-opensource@outlook.com.au>2020-01-06 15:46:13 +0000
committerBjorn Helgaas <bhelgaas@google.com>2020-01-29 16:57:28 -0600
commitf924c26e4ee651493f602da2a3d7ff628824e636 (patch)
tree43bc56d49089376d51bea22014c0593cb59d30af
parent7779385484dad7c95b624f7c9ee1aa07ab8cf43b (diff)
PCI: Consider alignment of hot-added bridges when assigning resources
Change pci_bus_distribute_available_resources() to better handle bridges with different resource alignment requirements. The arguments io, mmio and mmio_pref represent the start and end addresses of resource, into which we must fit the current bridge window. The steps taken by pci_bus_distribute_available_resources(): - For io, mmio and mmio_pref, increase .start to align with the alignment of the current bridge window (otherwise the current bridge window may not fit within the available range). - For io, mmio and mmio_pref, adjust the current bridge window to the size after the above. - Count the number of hotplug bridges and normal bridges on this bus. - If the total number of bridges is one, give that bridge all of the resources and return. - If there are no hotplug bridges, return. - For io, mmio and mmio_pref, increase .start by the amount required for each bridge resource on the bus for non hotplug bridges, giving extra room to make up for alignment of those resources. - For io, mmio and mmio_pref, calculate the resource size per hotplug bridge which is available after the previous steps. - For io, mmio and mmio_pref, distribute the resources to each hotplug bridge, with the sizes calculated above. The motivation for fixing this is enabling devices that require greater than 1MB alignment. This fixes the case where the user hot-adds devices with BAR alignment >1MB and Linux fails to assign resources to it. Link: https://bugzilla.kernel.org/show_bug.cgi?id=199581 Link: https://lore.kernel.org/r/PSXP216MB0438C2BFD0FD3691ED9C83F4803C0@PSXP216MB0438.KORP216.PROD.OUTLOOK.COM Reported-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Nicholas Johnson <nicholas.johnson-opensource@outlook.com.au> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
-rw-r--r--drivers/pci/setup-bus.c78
1 files changed, 46 insertions, 32 deletions
diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index 336c96c1d2d5..d76674ec712c 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -1869,18 +1869,33 @@ static void pci_bus_distribute_available_resources(struct pci_bus *bus,
struct resource mmio,
struct resource mmio_pref)
{
- resource_size_t available_io, available_mmio, available_mmio_pref;
- resource_size_t remaining_io, remaining_mmio, remaining_mmio_pref;
unsigned int normal_bridges = 0, hotplug_bridges = 0;
struct resource *io_res, *mmio_res, *mmio_pref_res;
struct pci_dev *dev, *bridge = bus->self;
- resource_size_t io_per_hp, mmio_per_hp, mmio_pref_per_hp;
+ resource_size_t io_per_hp, mmio_per_hp, mmio_pref_per_hp, align;
io_res = &bridge->resource[PCI_BRIDGE_RESOURCES + 0];
mmio_res = &bridge->resource[PCI_BRIDGE_RESOURCES + 1];
mmio_pref_res = &bridge->resource[PCI_BRIDGE_RESOURCES + 2];
/*
+ * The alignment of this bridge is yet to be considered, hence it must
+ * be done now before extending its bridge window.
+ */
+ align = pci_resource_alignment(bridge, io_res);
+ if (!io_res->parent && align)
+ io.start = min(ALIGN(io.start, align), io.end + 1);
+
+ align = pci_resource_alignment(bridge, mmio_res);
+ if (!mmio_res->parent && align)
+ mmio.start = min(ALIGN(mmio.start, align), mmio.end + 1);
+
+ align = pci_resource_alignment(bridge, mmio_pref_res);
+ if (!mmio_pref_res->parent && align)
+ mmio_pref.start = min(ALIGN(mmio_pref.start, align),
+ mmio_pref.end + 1);
+
+ /*
* Update additional resource list (add_list) to fill all the
* extra resource space available for this port except the space
* calculated in __pci_bus_size_bridges() which covers all the
@@ -1925,12 +1940,9 @@ static void pci_bus_distribute_available_resources(struct pci_bus *bus,
* extra space reduced by the minimal required space for the
* non-hotplug bridges.
*/
- remaining_io = available_io = resource_size(&io);
- remaining_mmio = available_mmio = resource_size(&mmio);
- remaining_mmio_pref = available_mmio_pref = resource_size(&mmio_pref);
-
for_each_pci_bridge(dev, bus) {
- const struct resource *res;
+ resource_size_t used_size;
+ struct resource *res;
if (dev->is_hotplug_bridge)
continue;
@@ -1940,24 +1952,39 @@ static void pci_bus_distribute_available_resources(struct pci_bus *bus,
* bridge and devices below it occupy.
*/
res = &dev->resource[PCI_BRIDGE_RESOURCES + 0];
- if (!res->parent && available_io > resource_size(res))
- remaining_io -= resource_size(res);
+ align = pci_resource_alignment(dev, res);
+ align = align ? ALIGN(io.start, align) - io.start : 0;
+ used_size = align + resource_size(res);
+ if (!res->parent)
+ io.start = min(io.start + used_size, io.end + 1);
res = &dev->resource[PCI_BRIDGE_RESOURCES + 1];
- if (!res->parent && available_mmio > resource_size(res))
- remaining_mmio -= resource_size(res);
+ align = pci_resource_alignment(dev, res);
+ align = align ? ALIGN(mmio.start, align) - mmio.start : 0;
+ used_size = align + resource_size(res);
+ if (!res->parent)
+ mmio.start = min(mmio.start + used_size, mmio.end + 1);
res = &dev->resource[PCI_BRIDGE_RESOURCES + 2];
- if (!res->parent && available_mmio_pref > resource_size(res))
- remaining_mmio_pref -= resource_size(res);
+ align = pci_resource_alignment(dev, res);
+ align = align ? ALIGN(mmio_pref.start, align) -
+ mmio_pref.start : 0;
+ used_size = align + resource_size(res);
+ if (!res->parent)
+ mmio_pref.start = min(mmio_pref.start + used_size,
+ mmio_pref.end + 1);
}
+ io_per_hp = div64_ul(resource_size(&io), hotplug_bridges);
+ mmio_per_hp = div64_ul(resource_size(&mmio), hotplug_bridges);
+ mmio_pref_per_hp = div64_ul(resource_size(&mmio_pref),
+ hotplug_bridges);
+
/*
* Go over devices on this bus and distribute the remaining
* resource space between hotplug bridges.
*/
for_each_pci_bridge(dev, bus) {
- resource_size_t align;
struct pci_bus *b;
b = dev->subordinate;
@@ -1969,29 +1996,16 @@ static void pci_bus_distribute_available_resources(struct pci_bus *bus,
* hotplug-capable downstream ports taking alignment into
* account.
*/
- align = pci_resource_alignment(bridge, io_res);
- io_per_hp = div64_ul(available_io, hotplug_bridges);
- io_per_hp = min(ALIGN(io_per_hp, align), remaining_io);
- remaining_io -= io_per_hp;
-
- align = pci_resource_alignment(bridge, mmio_res);
- mmio_per_hp = div64_ul(available_mmio, hotplug_bridges);
- mmio_per_hp = min(ALIGN(mmio_per_hp, align), remaining_mmio);
- remaining_mmio -= mmio_per_hp;
-
- align = pci_resource_alignment(bridge, mmio_pref_res);
- mmio_pref_per_hp = div64_ul(available_mmio_pref,
- hotplug_bridges);
- mmio_pref_per_hp = min(ALIGN(mmio_pref_per_hp, align),
- remaining_mmio_pref);
- remaining_mmio_pref -= mmio_pref_per_hp;
-
io.end = io.start + io_per_hp - 1;
mmio.end = mmio.start + mmio_per_hp - 1;
mmio_pref.end = mmio_pref.start + mmio_pref_per_hp - 1;
pci_bus_distribute_available_resources(b, add_list, io, mmio,
mmio_pref);
+
+ io.start += io_per_hp;
+ mmio.start += mmio_per_hp;
+ mmio_pref.start += mmio_pref_per_hp;
}
}