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d5b1a27143
A downstream port must be connected to a component register block. For restricted hosts the base address is determined from the RCRB. The RCRB is provided by the host's CEDT CHBS entry. Rework CEDT parser to get the RCRB and add code to extract the component register block from it. RCRB's BAR[0..1] point to the component block containing CXL subsystem component registers. MEMBAR extraction follows the PCI base spec here, esp. 64 bit extraction and memory range alignment (6.0, 7.5.1.2.1). The RCRB base address is cached in the cxl_dport per-host bridge so that the upstream port component registers can be retrieved later by an RCD (RCIEP) associated with the host bridge. Note: Right now the component register block is used for HDM decoder capability only which is optional for RCDs. If unsupported by the RCD, the HDM init will fail. It is future work to bypass it in this case. Co-developed-by: Terry Bowman <terry.bowman@amd.com> Signed-off-by: Terry Bowman <terry.bowman@amd.com> Signed-off-by: Robert Richter <rrichter@amd.com> Link: https://lore.kernel.org/r/Y4dsGZ24aJlxSfI1@rric.localdomain [djbw: introduce devm_cxl_add_rch_dport()] Link: https://lore.kernel.org/r/166993044524.1882361.2539922887413208807.stgit@dwillia2-xfh.jf.intel.com Reviewed-by: Dave Jiang <dave.jiang@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.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.