[PATCH 3/4] cxl: docs/platform/acpi/srat Add generic target documentation

[Dave Jiang <dave.jiang@intel.com>]

Add description in the SRAT document to descript the Generic Port
Affinity sub-table.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
 .../driver-api/cxl/platform/acpi/srat.rst     | 21 +++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/Documentation/driver-api/cxl/platform/acpi/srat.rst b/Documentation/driver-api/cxl/platform/acpi/srat.rst
index cc7687645de7..500413b96e70 100644
--- a/Documentation/driver-api/cxl/platform/acpi/srat.rst
+++ b/Documentation/driver-api/cxl/platform/acpi/srat.rst
@@ -42,3 +42,24 @@ Example ::
                Enabled : 1
          Hot Pluggable : 1
           Non-Volatile : 0
+
+
+Generic Port Affinity
+=====================
+The Generic Port Affinity subtable provides an association between a proximity
+domain and a device handle representing a Generic Port such as a CXL host
+bridge. With the association, latency and bandwidth numbers can be retrieved
+from the SRAT for the path between CPU(s) (initiator) and the Generic Port.
+This helps with constructing the performance coordinates for CXL devices that
+are hot-plugged and not able to be enumerated by the platform firmware.
+
+Example ::
+
+         Subtable Type : 06 [Generic Port Affinity]
+                Length : 20               <- 32d, length of table
+              Reserved : 00
+    Device Handle Type : 00               <- 0 - ACPI, 1 - PCI
+      Proximity Domain : 00000001
+         Device Handle : ACPI0016:01
+                 Flags : 00000001         <- Bit 0 (Enabled)
+              Reserved : 00000000
-- 
2.49.0