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A CXL 2.0 component is any entity in the CXL topology. All components have a analogous function in PCIe. Except for the CXL host bridge, all have a PCIe config space that is accessible via the common PCIe mechanisms. CXL components are enumerated via DVSEC fields in the extended PCIe header space. CXL components will minimally implement some subset of CXL.mem and CXL.cache registers defined in 8.2.5 of the CXL 2.0 specification. Two headers and a utility library are introduced to support the minimum functionality needed to enumerate components. The cxl_pci header manages bits associated with PCI, specifically the DVSEC and related fields. The cxl_component.h variant has data structures and APIs that are useful for drivers implementing any of the CXL 2.0 components. The library takes care of making use of the DVSEC bits and the CXL.[mem|cache] registers. Per spec, the registers are little endian. None of the mechanisms required to enumerate a CXL capable hostbridge are introduced at this point. Note that the CXL.mem and CXL.cache registers used are always 4B wide. It's possible in the future that this constraint will not hold. Signed-off-by: Ben Widawsky <ben.widawsky@intel.com> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Adam Manzanares <a.manzanares@samsung.com> Message-Id: <20220429144110.25167-3-Jonathan.Cameron@huawei.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> |
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| .. | ||
| cxl-component-utils.c | ||
| Kconfig | ||
| meson.build | ||