mb/google/brya: Add GPS _DSM subfunction support for Nvidia GPU

The _DSM subfunction for the Nvidia GN20 supports 1 additional
subfunction, known as GPS, which is required to support GPU Boost. This
implementation is minimal, essentially letting the GPU manage its own
temperature.

BUG=b:214581372
TEST=abuild

Signed-off-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Change-Id: I21331bd811a13212f3825bda44be44d1b5ae7c74
Reviewed-on: https://review.coreboot.org/c/coreboot/+/64995
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Eric Lai <eric_lai@quanta.corp-partner.google.com>

3 files changed, 104 insertions, 0 deletions

diff --git a/src/mainboard/google/brya/acpi/gps.asl b/src/mainboard/google/brya/acpi/gps.asl
new file mode 100644
index 0000000000..2e07a678cb
--- /dev/null
+++ b/src/mainboard/google/brya/acpi/gps.asl
@@ -0,0 +1,94 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#define GPS_FUNC_SUPPORT	0
+#define GPS_FUNC_GETCALLBACKS	0x13
+#define GPS_FUNC_PSHARESTATUS	0x20
+#define GPS_FUNC_PSHAREPARAMS	0x2a
+
+#define QUERY_GET_STATUS		0
+#define QUERY_GET_SUPPORTED_FIELDS	1
+#define QUERY_GET_CURRENT_LIMITS	2
+
+/* GPS return Package */
+Name (GPSP, Buffer (0x28) {0x0})
+CreateDWordField (GPSP, 0, RETN)
+CreateDWordField (GPSP, 4, VRV1)
+CreateDWordField (GPSP, 8, TGPU)
+
+/* GETCALLBACKS return value
+   [0]: Callback for post-mode set
+   [1]: Callback for pre-mode set
+   [2]: Callback for post power state transition */
+Name (GPSR, Buffer (4) { 0x4, 0x0, 0x0, 0x0 })
+
+Method (GPS, 2, Serialized)
+{
+	Switch (ToInteger (Arg0))
+	{
+		Case (GPS_FUNC_SUPPORT)
+		{
+			Return (ITOB(
+				(1 << GPS_FUNC_SUPPORT) |
+				(1 << GPS_FUNC_GETCALLBACKS) |
+				(1 << GPS_FUNC_PSHARESTATUS) |
+				(1 << GPS_FUNC_PSHAREPARAMS)))
+		}
+		Case (GPS_FUNC_GETCALLBACKS)
+		{
+			CreateDWordField (Arg1, 0, QURY)
+
+			/* Driver querying for which callbacks the ACPI code
+			   wants callbacks for. */
+			If (QURY == 0)
+			{
+				Return (GPSR)
+			}
+
+			If (QURY & 0x4)
+			{
+				Printf("GPS: Kernel driver callback post power state transition")
+				Return (GPSR)
+			}
+		}
+		Case (GPS_FUNC_PSHARESTATUS)
+		{
+			Return (ITOB(
+				(0 << 0) |	/* GPS_FUNC_PSHAREPARAMS should not be called
+				                   again after initialization, i.e., its return
+						   value is not dynamically updated. */
+				(1 << 0) |	/* System uses both a GPIO and ACPI notification
+						   codes to set multiple GPU power limits. */
+				(0 << 21)))	/* EDPpeak limit is default */
+		}
+		Case (GPS_FUNC_PSHAREPARAMS)
+		{
+			CreateField (Arg1, 0, 4, QUTY)	 /* Query type */
+
+			/* Version of return value */
+			VRV1 = 0x10000
+			Switch (ToInteger (QUTY))
+			{
+				Case (QUERY_GET_STATUS)
+				{
+					Return (GPSP)
+				}
+				Case (QUERY_GET_SUPPORTED_FIELDS)
+				{
+					/* Only GPU temperature is supported */
+					RETN = 0x100 | ToInteger (QUTY)
+					Return (GPSP)
+				}
+				Case (QUERY_GET_CURRENT_LIMITS)
+				{
+					/* Request a limit of '0' for the GPU temperature,
+					   meaning there is no limit. */
+					RETN = 0x102
+					TGPU = 0
+					Return (GPSP)
+				}
+			}
+		}
+	}
+
+	Return (NV_ERROR_UNSUPPORTED)
+}
diff --git a/src/mainboard/google/brya/acpi/gpu_defines.h b/src/mainboard/google/brya/acpi/gpu_defines.h
index ec79f81b7d..ec17a1c452 100644
--- a/src/mainboard/google/brya/acpi/gpu_defines.h
+++ b/src/mainboard/google/brya/acpi/gpu_defines.h
@@ -39,8 +39,10 @@
 #define UUID_NVJT		"cbeca351-067b-4924-9cbd-b46b00b86f34"
 #define UUID_NBCI		"d4a50b75-65c7-46f7-bfb7-41514cea0244"
 #define UUID_NVPCF		"36b49710-2483-11e7-9598-0800200c9a66"
+#define UUID_GPS		"a3132d01-8cda-49ba-a52e-bc9d46df6b81"
 
 #define REVISION_MIN_NVOP	0x100
 #define REVISION_MIN_NVJT	0x100
 #define REVISION_MIN_NBCI	0x102
 #define REVISION_MIN_NVPCF	0x200
+#define REVISION_MIN_GPS	0x200
diff --git a/src/mainboard/google/brya/acpi/gpu_top.asl b/src/mainboard/google/brya/acpi/gpu_top.asl
index 6b492231e3..f3b348aba8 100644
--- a/src/mainboard/google/brya/acpi/gpu_top.asl
+++ b/src/mainboard/google/brya/acpi/gpu_top.asl
@@ -24,6 +24,7 @@ Scope (\_SB.PCI0.PEG0)
 		#include "nvjt.asl"
 		#include "nbci.asl"
 		#include "nvpcf.asl"
+		#include "gps.asl"
 
 		Method (_DSM, 4, Serialized)
 		{
@@ -55,6 +56,13 @@ Scope (\_SB.PCI0.PEG0)
 					Return (NPCF (Arg2, Arg3))
 				}
 			}
+			ElseIf (Arg0 == ToUUID (UUID_GPS))
+			{
+				If (ToInteger (Arg1) != REVISION_MIN_GPS)
+				{
+					Return (GPS (Arg2, Arg3))
+				}
+			}
 
 			Return (NV_ERROR_UNSUPPORTED)
 		}