The PCI subsystem always assumes that I/O is supported on root bus and tries to assign an I/O window to each child bus even if that is not the case.
The use cases is on Intel 8 socket system that have 8 root buses, last two root buses would not have io port resources from _CRS. Check if root bus supports I/O, and later during sizing and assigning, check that flags and skip those resources. Signed-off-by: Yinghai Lu <[email protected]> --- drivers/pci/probe.c | 6 ++++++ drivers/pci/setup-bus.c | 9 +++++++++ include/linux/pci.h | 1 + 3 files changed, 16 insertions(+) diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 52ddc45..6f0488c 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -345,6 +345,9 @@ static void pci_read_bridge_io(struct pci_bus *child) struct pci_bus_region region; struct resource *res; + if (!pci_find_host_bridge(child)->has_ioport) + return; + io_mask = PCI_IO_RANGE_MASK; io_granularity = 0x1000; if (dev->io_window_1k) { @@ -2231,6 +2234,9 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus, bus_addr[0] = '\0'; dev_info(&b->dev, "root bus resource %pR%s\n", res, bus_addr); + if (resource_type(res) == IORESOURCE_IO) + bridge->has_ioport = 1; + if (resource_type(res) == IORESOURCE_MEM) { if ((res->end - offset) > 0xffffffff) bridge->has_mem64 = 1; diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c index d07ba87..076b5db 100644 --- a/drivers/pci/setup-bus.c +++ b/drivers/pci/setup-bus.c @@ -225,6 +225,10 @@ static void pdev_assign_resources_prepare(struct pci_dev *dev, if (resource_disabled(r) || r->parent) continue; + if ((r->flags & IORESOURCE_IO) && + !pci_find_host_bridge(dev->bus)->has_ioport) + continue; + r_align = __pci_resource_alignment(dev, r, realloc_head); if (!r_align) { dev_warn(&dev->dev, "BAR %d: %pR has bogus alignment\n", @@ -1188,6 +1192,11 @@ static void pbus_size_io(struct pci_bus *bus, resource_size_t min_size, min_size = 0; } + if (!pci_find_host_bridge(bus)->has_ioport) { + b_res->flags |= IORESOURCE_UNSET | IORESOURCE_DISABLED; + return; + } + min_align = window_alignment(bus, IORESOURCE_IO); list_for_each_entry(dev, &bus->devices, bus_list) { int i; diff --git a/include/linux/pci.h b/include/linux/pci.h index 41d06ce..463094a 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -409,6 +409,7 @@ struct pci_host_bridge { void *release_data; unsigned int ignore_reset_delay:1; /* for entire hierarchy */ unsigned int has_mem64:1; + unsigned int has_ioport:1; /* Resource alignment requirements */ resource_size_t (*align_resource)(struct pci_dev *dev, const struct resource *res, -- 1.8.4.5
