From 03db42adfeeabe856dbb6894dd3aaff55838330a Mon Sep 17 00:00:00 2001 From: Bjorn Helgaas Date: Wed, 4 Nov 2009 10:39:18 -0700 Subject: x86/PCI: fix bogus host bridge window start/end alignment from _CRS PCI device BARs are guaranteed to start and end on at least a four-byte (I/O) or a sixteen-byte (MMIO) boundary because they're aligned on their size and the low BAR bits are reserved. PCI-to-PCI bridge apertures have even larger alignment restrictions. However, some BIOSes (e.g., HP DL360 BIOS P31) report host bridge windows like "[io 0x0000-0x2cfe]". This is wrong because it excludes the last port at 0x2cff: it's impossible for a downstream device to claim 0x2cfe without also claiming 0x2cff. In fact, this BIOS configures a device behind the bridge to "[io 0x2c00-0x2cff]", so we know the window actually does include 0x2cff. This patch rounds the start and end of apertures to the appropriate boundary. I experimentally determined that Windows contains a similar workaround; details here: http://bugzilla.kernel.org/show_bug.cgi?id=14337 Signed-off-by: Bjorn Helgaas Signed-off-by: Jesse Barnes --- arch/x86/pci/acpi.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) (limited to 'arch') diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c index 54db5a04b5e..8ddf4f4c725 100644 --- a/arch/x86/pci/acpi.c +++ b/arch/x86/pci/acpi.c @@ -59,6 +59,30 @@ bus_has_transparent_bridge(struct pci_bus *bus) return false; } +static void +align_resource(struct acpi_device *bridge, struct resource *res) +{ + int align = (res->flags & IORESOURCE_MEM) ? 16 : 4; + + /* + * Host bridge windows are not BARs, but the decoders on the PCI side + * that claim this address space have starting alignment and length + * constraints, so fix any obvious BIOS goofs. + */ + if (res->start & (align - 1)) { + dev_printk(KERN_DEBUG, &bridge->dev, + "host bridge window %pR invalid; " + "aligning start to %d-byte boundary\n", res, align); + res->start &= ~(align - 1); + } + if ((res->end + 1) & (align - 1)) { + dev_printk(KERN_DEBUG, &bridge->dev, + "host bridge window %pR invalid; " + "aligning end to %d-byte boundary\n", res, align); + res->end = roundup(res->end, align) - 1; + } +} + static acpi_status setup_resource(struct acpi_resource *acpi_res, void *data) { @@ -107,6 +131,7 @@ setup_resource(struct acpi_resource *acpi_res, void *data) res->start = start; res->end = end; res->child = NULL; + align_resource(info->bridge, res); if (!(pci_probe & PCI_USE__CRS)) { dev_printk(KERN_DEBUG, &info->bridge->dev, -- cgit v1.2.3-70-g09d2