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During a Host Bridge's downstream port enumeration the CHBS entries in the CEDT table are parsed, its Component Register base address extracted and then stored in struct cxl_dport. The CHBS may contain either the RCRB (RCH mode) or the Host Bridge's Component Registers (CHBCR, VH mode). The RCRB further contains the CXL downstream port register base address, while in VH mode the CXL Downstream Switch Ports are visible in the PCI hierarchy and the DP's component regs are disovered using the CXL DVSEC register locator capability. The Component Registers derived from the CHBS for both modes are different and thus also must be treated differently. That is, in RCH mode, the component regs base should be bound to the dport, but in VH mode to the CXL host bridge's port object. The current implementation stores the CHBCR in addition in struct cxl_dport and copies it later from there to struct cxl_port. As a result, the dport contains the wrong Component Registers base address and, e.g. the RAS capability of a CXL Root Port cannot be detected. To fix the CHBCR binding, attach it directly to the Host Bridge's @cxl_port structure. Do this during port creation of the Host Bridge in add_host_bridge_uport(). Factor out CHBS parsing code in add_host_bridge_dport() and use it in both functions. Co-developed-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Robert Richter <rrichter@amd.com> Signed-off-by: Terry Bowman <terry.bowman@amd.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/20230622205523.85375-10-terry.bowman@amd.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.