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, in 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 Thunderbolt with native PCI enumeration, enabling external graphics cards and other devices with bridge alignment higher than 1MB. This fixes the use case where the user hot-adds Thunderbolt devices containing PCI devices with BAR alignment >1M and having the resources fail to assign. Link: https://bugzilla.kernel.org/show_bug.cgi?id=199581 Reported-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> Signed-off-by: Nicholas Johnson <nicholas.johnson-opensource@xxxxxxxxxxxxxx> --- drivers/pci/setup-bus.c | 77 ++++++++++++++++++++++++----------------- 1 file changed, 46 insertions(+), 31 deletions(-) diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c index 269082261..8b39b9ebb 100644 --- a/drivers/pci/setup-bus.c +++ b/drivers/pci/setup-bus.c @@ -1863,9 +1863,7 @@ static void pci_bus_distribute_available_resources(struct pci_bus *bus, struct resource mmio, struct resource mmio_pref) { - resource_size_t remaining_io, remaining_mmio, remaining_mmio_pref; - resource_size_t io_per_hp, mmio_per_hp, mmio_pref_per_hp; - resource_size_t avail_io, avail_mmio, avail_mmio_pref; + resource_size_t io_per_hp, mmio_per_hp, mmio_pref_per_hp, align; unsigned int normal_bridges = 0, hotplug_bridges = 0; struct resource *io_res, *mmio_res, *mmio_pref_res; struct pci_dev *dev, *bridge = bus->self; @@ -1874,6 +1872,23 @@ static void pci_bus_distribute_available_resources(struct pci_bus *bus, 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 @@ -1919,12 +1934,9 @@ 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 = avail_io = resource_size(&io); - remaining_mmio = avail_mmio = resource_size(&mmio); - remaining_mmio_pref = avail_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; @@ -1934,24 +1946,39 @@ 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 && avail_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 && avail_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 && avail_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; @@ -1963,28 +1990,16 @@ 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(avail_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(avail_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(avail_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; } } -- 2.24.1
