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authorDan Williams <dan.j.williams@intel.com>2022-04-13 01:36:17 -0600
committerDan Williams <dan.j.williams@intel.com>2022-04-28 14:01:54 -0700
commit241d26bc26add2e2867c546f7474902406d37c60 (patch)
treef30db393acfd7adf289c5b2d22abfc277276c232 /include/acpi
parentcc10eee95204579fcd66fd5965073fdcbf629676 (diff)
PCI/ACPI: Prefer CXL _OSC instead of PCIe _OSC for CXL host bridges
OB In preparation for negotiating OS control of CXL _OSC features, do the minimal enabling to use CXL _OSC to handle the base PCIe feature negotiation. Recall that CXL _OSC is a super-set of PCIe _OSC and the CXL 2.0 specification mandates: "If a CXL Host Bridge device exposes CXL _OSC, CXL aware OSPM shall evaluate CXL _OSC and not evaluate PCIe _OSC." Rather than pass a boolean flag alongside @root to all the helper functions that need to consider PCIe specifics, add is_pcie() and is_cxl() helper functions to check the flavor of @root. This also allows for dynamic fallback to PCIe _OSC in cases where an attempt to use CXL _OXC fails. This can happen on CXL 1.1 platforms that publish ACPI0016 devices to indicate CXL host bridges, but do not publish the optional CXL _OSC method. CXL _OSC is mandatory for CXL 2.0 hosts. Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Robert Moore <robert.moore@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Davidlohr Bueso <dave@stgolabs.net> Signed-off-by: Vishal Verma <vishal.l.verma@intel.com> Link: https://lore.kernel.org/r/20220413073618.291335-3-vishal.l.verma@intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'include/acpi')
-rw-r--r--include/acpi/acpi_bus.h6
1 files changed, 6 insertions, 0 deletions
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index c4b78c21d793..305ebf2a3fa7 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -582,10 +582,16 @@ int unregister_acpi_bus_type(struct acpi_bus_type *);
int acpi_bind_one(struct device *dev, struct acpi_device *adev);
int acpi_unbind_one(struct device *dev);
+enum acpi_bridge_type {
+ ACPI_BRIDGE_TYPE_PCIE = 1,
+ ACPI_BRIDGE_TYPE_CXL,
+};
+
struct acpi_pci_root {
struct acpi_device * device;
struct pci_bus *bus;
u16 segment;
+ int bridge_type;
struct resource secondary; /* downstream bus range */
u32 osc_support_set; /* _OSC state of support bits */