Documentation: RAS: Add index and address translation section

There are a lot of RAS topic to document, and there are a lot of details
for each topic.

Prep for this by adding an index for the RAS directory. This will
provide a top-level document and table of contents. It also provides the
option to build the RAS directory individually using "make SPHINXDIRS=".

Start a section on address translation. This will be expanded with
details for future translation methods and how they're used in the
kernel.

Move the error decoding topic to its own section. Links to other error
decoding kernel docs will be added.

Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20240123041401.79812-4-yazen.ghannam@amd.com

5 files changed, 43 insertions, 9 deletions

diff --git a/Documentation/RAS/address-translation.rst b/Documentation/RAS/address-translation.rst
new file mode 100644
index 000000000000..f0ca17b43cd3
--- /dev/null
+++ b/Documentation/RAS/address-translation.rst
@@ -0,0 +1,24 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Address translation
+===================
+
+x86 AMD
+-------
+
+Zen-based AMD systems include a Data Fabric that manages the layout of
+physical memory. Devices attached to the Fabric, like memory controllers,
+I/O, etc., may not have a complete view of the system physical memory map.
+These devices may provide a "normalized", i.e. device physical, address
+when reporting memory errors. Normalized addresses must be translated to
+a system physical address for the kernel to action on the memory.
+
+AMD Address Translation Library (CONFIG_AMD_ATL) provides translation for
+this case.
+
+Glossary of acronyms used in address translation for Zen-based systems
+
+* CCM               = Cache Coherent Moderator
+* COD               = Cluster-on-Die
+* COH_ST            = Coherent Station
+* DF                = Data Fabric
diff --git a/Documentation/RAS/ras.rst b/Documentation/RAS/error-decoding.rst
index 2556b397cd27..26a72f3fe5de 100644
--- a/Documentation/RAS/ras.rst
+++ b/Documentation/RAS/error-decoding.rst
@@ -1,15 +1,10 @@
 .. SPDX-License-Identifier: GPL-2.0
 
-Reliability, Availability and Serviceability features
-=====================================================
-
-This documents different aspects of the RAS functionality present in the
-kernel.
-
 Error decoding
----------------
+==============
 
-* x86
+x86
+---
 
 Error decoding on AMD systems should be done using the rasdaemon tool:
 https://github.com/mchehab/rasdaemon/
diff --git a/Documentation/RAS/index.rst b/Documentation/RAS/index.rst
new file mode 100644
index 000000000000..2794c1816e90
--- /dev/null
+++ b/Documentation/RAS/index.rst
@@ -0,0 +1,14 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+===========================================================
+Reliability, Availability and Serviceability (RAS) features
+===========================================================
+
+This documents different aspects of the RAS functionality present in the
+kernel.
+
+.. toctree::
+   :maxdepth: 2
+
+   error-decoding
+   address-translation
diff --git a/Documentation/index.rst b/Documentation/index.rst
index 36e61783437c..07f2aa07f0fa 100644
--- a/Documentation/index.rst
+++ b/Documentation/index.rst
@@ -113,7 +113,7 @@ to ReStructured Text format, or are simply too old.
    :maxdepth: 1
 
    staging/index
-   RAS/ras
+   RAS/index
 
 
 Translations
diff --git a/MAINTAINERS b/MAINTAINERS
index 25537a37338e..5b945fd5a3b9 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -18359,6 +18359,7 @@ M:	Tony Luck <tony.luck@intel.com>
 M:	Borislav Petkov <bp@alien8.de>
 L:	linux-edac@vger.kernel.org
 S:	Maintained
+F:	Documentation/RAS/
 F:	Documentation/admin-guide/ras.rst
 F:	drivers/ras/
 F:	include/linux/ras.h