mb/google/poppy/variant/nocturne: update PL2 based on CPU sku

This patch adds a function to overwrite PL2 setting based on CPU
sku. From doc #594883, PL2 is 18W for AML-Y.

BUG=b:110890675
BRANCH=None
TEST=emerge-nocturne coreboot chromeos-bootimage & test with AML-Y
     and KBL-Y skus.

Change-Id: Idfdc0c2434fdef56a7c25df05e640837a5096973
Signed-off-by: Nick Vaccaro <nvaccaro@google.com>
Reviewed-on: https://review.coreboot.org/27997
Reviewed-by: Caveh Jalali <caveh@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

2 files changed, 47 insertions, 0 deletions

diff --git a/src/mainboard/google/poppy/variants/nocturne/Makefile.inc b/src/mainboard/google/poppy/variants/nocturne/Makefile.inc
index b78b7a3c0e..c17a49c08b 100644
--- a/src/mainboard/google/poppy/variants/nocturne/Makefile.inc
+++ b/src/mainboard/google/poppy/variants/nocturne/Makefile.inc
@@ -19,3 +19,4 @@ romstage-y += memory.c
 
 ramstage-y += gpio.c
 ramstage-y += nhlt.c
+ramstage-y += mainboard.c
diff --git a/src/mainboard/google/poppy/variants/nocturne/mainboard.c b/src/mainboard/google/poppy/variants/nocturne/mainboard.c
new file mode 100644
index 0000000000..28d3d1b24d
--- /dev/null
+++ b/src/mainboard/google/poppy/variants/nocturne/mainboard.c
@@ -0,0 +1,46 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2018 Google Inc.
+ * Copyright (C) 2018 Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <baseboard/variants.h>
+#include <chip.h>
+#include <device/device.h>
+#include <device/pci_ids.h>
+#include <device/pci_ops.h>
+
+/* PL2 limit in watts for AML and KBL */
+#define PL2_AML	18
+#define PL2_KBL	15
+
+static uint32_t get_pl2(void)
+{
+	uint16_t id;
+	id = pci_read_config16(SA_DEV_IGD, PCI_DEVICE_ID);
+	/* Assume we only have KLB-Y and AML-Y SKUs */
+	if (id == PCI_DEVICE_ID_INTEL_KBL_GT2_SULXM)
+		return PL2_KBL;
+
+	return PL2_AML;
+}
+
+/* Override dev tree settings per board */
+void variant_devtree_update(void)
+{
+	struct device *root = SA_DEV_ROOT;
+	config_t *cfg = root->chip_info;
+
+	/* Update PL2 based on CPU */
+	cfg->tdp_pl2_override = get_pl2();
+}