cxl: docs/platform/example-configs documentation

Add example ACPI Table configurations for different sample platforms.

Signed-off-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Link: https://patch.msgid.link/20250512162134.3596150-7-gourry@gourry.net
Signed-off-by: Dave Jiang <dave.jiang@intel.com>

Documentation/driver-api/cxl/platform/example-configurations/multi-dev-per-hb.rst

@@ -0,0 +1,90 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+================================
+Multiple Devices per Host Bridge
+================================
+
+In this example system we will have a single socket and one CXL host bridge.
+There are two CXL memory expanders with 4GB attached to the host bridge.
+
+Things to note:
+
+* Intra-Bridge interleave is not described here.
+* The expanders are described by a single CEDT/CFMWS.
+* This CEDT/SRAT describes one node for both devices.
+* There is only one proximity domain the HMAT for both devices.
+
+CEDT ::
+
+            Subtable Type : 00 [CXL Host Bridge Structure]
+                 Reserved : 00
+                   Length : 0020
+   Associated host bridge : 00000007
+    Specification version : 00000001
+                 Reserved : 00000000
+            Register base : 0000010370400000
+          Register length : 0000000000010000
+
+            Subtable Type : 01 [CXL Fixed Memory Window Structure]
+                 Reserved : 00
+                   Length : 002C
+                 Reserved : 00000000
+      Window base address : 0000001000000000
+              Window size : 0000000200000000
+ Interleave Members (2^n) : 00
+    Interleave Arithmetic : 00
+                 Reserved : 0000
+              Granularity : 00000000
+             Restrictions : 0006
+                    QtgId : 0001
+             First Target : 00000007
+
+SRAT ::
+
+         Subtable Type : 01 [Memory Affinity]
+                Length : 28
+      Proximity Domain : 00000001
+             Reserved1 : 0000
+          Base Address : 0000001000000000
+        Address Length : 0000000200000000
+             Reserved2 : 00000000
+ Flags (decoded below) : 0000000B
+             Enabled : 1
+       Hot Pluggable : 1
+        Non-Volatile : 0
+
+HMAT ::
+
+               Structure Type : 0001 [SLLBI]
+                    Data Type : 00   [Latency]
+ Target Proximity Domain List : 00000000
+ Target Proximity Domain List : 00000001
+                        Entry : 0080
+                        Entry : 0100
+
+               Structure Type : 0001 [SLLBI]
+                    Data Type : 03   [Bandwidth]
+ Target Proximity Domain List : 00000000
+ Target Proximity Domain List : 00000001
+                        Entry : 1200
+                        Entry : 0200
+
+SLIT ::
+
+     Signature : "SLIT"    [System Locality Information Table]
+    Localities : 0000000000000003
+  Locality   0 : 10 20
+  Locality   1 : FF 0A
+
+DSDT ::
+
+  Scope (_SB)
+  {
+    Device (S0D0)
+    {
+        Name (_HID, "ACPI0016" /* Compute Express Link Host Bridge */)  // _HID: Hardware ID
+        ...
+        Name (_UID, 0x07)  // _UID: Unique ID
+    }
+    ...
+  }