From 2c62e8492ed7358bbe7da51666c7e0f6da9474ee Mon Sep 17 00:00:00 2001 From: Jiang Liu Date: Thu, 30 Apr 2015 12:41:28 +0800 Subject: x86/PCI/ACPI: Make all resources except [io 0xcf8-0xcff] available on PCI bus An IO port or MMIO resource assigned to a PCI host bridge may be consumed by the host bridge itself or available to its child bus/devices. The ACPI specification defines a bit (Producer/Consumer) to tell whether the resource is consumed by the host bridge itself, but firmware hasn't used that bit consistently, so we can't rely on it. Before commit 593669c2ac0f ("x86/PCI/ACPI: Use common ACPI resource interfaces to simplify implementation"), arch/x86/pci/acpi.c ignored all IO port resources defined by acpi_resource_io and acpi_resource_fixed_io to filter out IO ports consumed by the host bridge itself. Commit 593669c2ac0f ("x86/PCI/ACPI: Use common ACPI resource interfaces to simplify implementation") started accepting all IO port and MMIO resources, which caused a regression that IO port resources consumed by the host bridge itself became available to its child devices. Then commit 63f1789ec716 ("x86/PCI/ACPI: Ignore resources consumed by host bridge itself") ignored resources consumed by the host bridge itself by checking the IORESOURCE_WINDOW flag, which accidently removed MMIO resources defined by acpi_resource_memory24, acpi_resource_memory32 and acpi_resource_fixed_memory32. On x86 and IA64 platforms, all IO port and MMIO resources are assumed to be available to child bus/devices except one special case: IO port [0xCF8-0xCFF] is consumed by the host bridge itself to access PCI configuration space. So explicitly filter out PCI CFG IO ports[0xCF8-0xCFF]. This solution will also ease the way to consolidate ACPI PCI host bridge common code from x86, ia64 and ARM64. Related ACPI table are archived at: https://bugzilla.kernel.org/show_bug.cgi?id=94221 Related discussions at: http://patchwork.ozlabs.org/patch/461633/ https://lkml.org/lkml/2015/3/29/304 Fixes: 63f1789ec716 (Ignore resources consumed by host bridge itself) Reported-by: Bernhard Thaler Signed-off-by: Jiang Liu Cc: 4.0+ # 4.0+ Reviewed-by: Bjorn Helgaas Signed-off-by: Rafael J. Wysocki --- arch/x86/pci/acpi.c | 24 ++++++++++++++++++++++-- 1 file changed, 22 insertions(+), 2 deletions(-) (limited to 'arch/x86/pci/acpi.c') diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c index e4695985f9de..d93963340c3c 100644 --- a/arch/x86/pci/acpi.c +++ b/arch/x86/pci/acpi.c @@ -325,6 +325,26 @@ static void release_pci_root_info(struct pci_host_bridge *bridge) kfree(info); } +/* + * An IO port or MMIO resource assigned to a PCI host bridge may be + * consumed by the host bridge itself or available to its child + * bus/devices. The ACPI specification defines a bit (Producer/Consumer) + * to tell whether the resource is consumed by the host bridge itself, + * but firmware hasn't used that bit consistently, so we can't rely on it. + * + * On x86 and IA64 platforms, all IO port and MMIO resources are assumed + * to be available to child bus/devices except one special case: + * IO port [0xCF8-0xCFF] is consumed by the host bridge itself + * to access PCI configuration space. + * + * So explicitly filter out PCI CFG IO ports[0xCF8-0xCFF]. + */ +static bool resource_is_pcicfg_ioport(struct resource *res) +{ + return (res->flags & IORESOURCE_IO) && + res->start == 0xCF8 && res->end == 0xCFF; +} + static void probe_pci_root_info(struct pci_root_info *info, struct acpi_device *device, int busnum, int domain, @@ -346,8 +366,8 @@ static void probe_pci_root_info(struct pci_root_info *info, "no IO and memory resources present in _CRS\n"); else resource_list_for_each_entry_safe(entry, tmp, list) { - if ((entry->res->flags & IORESOURCE_WINDOW) == 0 || - (entry->res->flags & IORESOURCE_DISABLED)) + if ((entry->res->flags & IORESOURCE_DISABLED) || + resource_is_pcicfg_ioport(entry->res)) resource_list_destroy_entry(entry); else entry->res->name = info->name; -- cgit v1.2.3