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Ben Widawsky authored
An HDM decoder is defined in the CXL 2.0 specification as a mechanism that allow devices and upstream ports to claim memory address ranges and participate in interleave sets. HDM decoder registers are within the component register block defined in CXL 2.0 8.2.3 CXL 2.0 Component Registers as part of the CXL.cache and CXL.mem subregion. The Component Register Block is found via the Register Locator DVSEC in a similar fashion to how the CXL Device Register Block is found. The primary difference is the capability id size of the Component Register Block is a single DWORD instead of 4 DWORDS. It's now possible to configure a CXL type 3 device's HDM decoder. Such programming is expected for CXL devices with persistent memory, and hot plugged CXL devices that participate in CXL.mem with volatile memory. Add probe and mapping functions for the component register blocks. Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Co-developed-by: Ira Weiny <ira.weiny@intel.com> Signed-off-by: Ira Weiny <ira.weiny@intel.com> Co-developed-by: Vishal Verma <vishal.l.verma@intel.com> Signed-off-by: Vishal Verma <vishal.l.verma@intel.com> Signed-off-by: Ben Widawsky <ben.widawsky@intel.com> Link: https://lore.kernel.org/r/20210528004922.3980613-6-ira.weiny@intel.comSigned-off-by: Dan Williams <dan.j.williams@intel.com>
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