Documentation/drivers/dptf: Add oem variables support

Add oem variables information with usage example.

BRANCH=None
BUG=b:187253038
TEST=Built and tested on dedede board

Change-Id: I45db17f6ee3328da28f985c6854d65a430c9c61b
Signed-off-by: Sumeet Pawnikar <sumeet.r.pawnikar@intel.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/55846
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>

1 files changed, 16 insertions, 0 deletions

diff --git a/Documentation/drivers/dptf.md b/Documentation/drivers/dptf.md
index 327d6865b21e..1e5674c9d9bf 100644
--- a/Documentation/drivers/dptf.md
+++ b/Documentation/drivers/dptf.md
@@ -311,3 +311,19 @@ table for a given temperature threshold.
 1) Hysteresis - The amount of hysteresis implemented in either circuitry or
    the firmware that reads the temperature sensor (in degrees C).
 2) Name - This name is applied to the _STR property of the sensor
+
+## OEM Variables
+Platform vendors can define an array of OEM-specific values as OEM variables
+to be used under DPTF policy. There are total six OEM variables available.
+These can be used in AP policy for more specific actions. These OEM variables
+can be defined as below mentioned example and can be used any variable between
+[0], [1],...,[5]. Platform vendors can enable and use this for specific platform
+by defining OEM variables macro under board variant.
+
+Example:
+```C
+register "oem_data.oem_variables" = "{
+   [1] = 0x6,
+   [3] = 0x1
+}"
+```