mb/google/poppy/variants/nautilus: Bump VCC_SA voltage offset 75mV

Nautilus-Wifi with m3 AP got a halt issue during CTS test.

Nautilus-Wifi was FCS with Celeron AP first and also its PCB/BOM was
validated only with Celeron. Since Celeron deos not support turbo
boost mode, its steady power demend and lower CPU frequency may not
reflect the potential noise hidden inside the board.

Bumping VCC_SA voltage offset 75mV confirmed works to mitigate the
potential noise coupling to VCC_GT/SA, and we verified this change
makes this issue go away on Nautilus-Wifi board.

Nautilus-LTE doesn't show this issue, since it has 10L PCB, will have
better grounding and less noise/ripple than 8L PCB.

BUG=b:111417632
BRANCH=poppy
TEST=Verified CTS test pass without an issue.

Change-Id: Id13fcc36a5b6ed42620c66f57a7303f30bff1a50
Signed-off-by: Seunghwan Kim <sh_.kim@samsung.com>
Reviewed-on: https://review.coreboot.org/28439
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>

src/mainboard/google/poppy/romstage.c

@@ -173,4 +173,7 @@ void mainboard_memory_init_params(FSPM_UPD *mupd)
 	mem_cfg->MemorySpdPtr00 = mainboard_get_spd_data(p.type, p.use_sec_spd);
 	mem_cfg->MemorySpdPtr10 = mem_cfg->MemorySpdPtr00;
 	mem_cfg->MemorySpdDataLen = spd_info[p.type].len;
+
+	mem_cfg->SaOcSupport = p.enable_sa_oc_support;
+	mem_cfg->SaVoltageOffset = p.sa_voltage_offset_val;
 }

src/mainboard/google/poppy/variants/baseboard/include/baseboard/variants.h

@@ -54,6 +54,12 @@ struct memory_params {
 	const void *rcomp_target;
 	size_t rcomp_target_size;
 	bool use_sec_spd;
+
+	/* Enable SA overclocking mailbox commands */
+	bool enable_sa_oc_support;
+
+	/* The voltage offset applied to the SA in mV. 1000(mV) = Maximum */
+	uint16_t sa_voltage_offset_val;
 };
 
 void variant_memory_params(struct memory_params *p);

src/mainboard/google/poppy/variants/nautilus/Makefile.inc

@@ -7,9 +7,11 @@ bootblock-y += gpio.c
 
 romstage-y += memory.c
 romstage-y += gpio.c
+romstage-y += sku.c
 
 ramstage-y += gpio.c
 ramstage-y += nhlt.c
 ramstage-y += mainboard.c
+ramstage-y += sku.c
 
 smm-$(CONFIG_HAVE_SMI_HANDLER) += smihandler.c

src/mainboard/google/poppy/variants/nautilus/mainboard.c

@@ -15,32 +15,16 @@
 
 #include <baseboard/variants.h>
 #include <chip.h>
-#include <gpio.h>
 #include <device/device.h>
+#include <device/pci.h>
 #include <smbios.h>
 #include <string.h>
 #include <variant/sku.h>
 
-uint32_t variant_board_sku(void)
-{
-	static uint32_t sku_id = SKU_UNKNOWN;
-
-	if (sku_id != SKU_UNKNOWN)
-		return sku_id;
-
-	/*
-	*  Nautilus uses GPP_B20 to determine SKU
-	*  0 - Wifi SKU
-	*  1 - LTE SKU
-	*/
-	gpio_input_pulldown(GPP_B20);
-	if (!gpio_get(GPP_B20))
-		sku_id = SKU_0_NAUTILUS;
-	else
-		sku_id = SKU_1_NAUTILUS_LTE;
-
-	return sku_id;
-}
+#define R_PCH_OC_WDT_CTL		0x54
+#define B_PCH_OC_WDT_CTL_FORCE_ALL	BIT15
+#define B_PCH_OC_WDT_CTL_EN		BIT14
+#define B_PCH_OC_WDT_CTL_UNXP_RESET_STS	BIT22
 
 const char *smbios_mainboard_sku(void)
 {
@@ -57,11 +41,22 @@ void variant_devtree_update(void)
 	uint32_t sku_id = variant_board_sku();
 	struct device *root = SA_DEV_ROOT;
 	config_t *cfg = root->chip_info;
+	uint16_t abase;
+	uint32_t val32;
 
 	switch (sku_id) {
 	case SKU_0_NAUTILUS:
 		/* Disable LTE module */
 		cfg->usb3_ports[3].enable = 0;
+
+		/* OC_WDT has been enabled in FSP-M by enabling SaOcSupport.
+		 * We should clear it to prevent turning the system off. */
+		abase = pci_read_config16(PCH_DEV_PMC, ABASE) & 0xfffc;
+		val32 = inl(abase + R_PCH_OC_WDT_CTL);
+		val32 &= ~(B_PCH_OC_WDT_CTL_EN |
+			B_PCH_OC_WDT_CTL_FORCE_ALL |
+			B_PCH_OC_WDT_CTL_UNXP_RESET_STS);
+		outl(val32, abase + R_PCH_OC_WDT_CTL);
 		break;
 
 	case SKU_1_NAUTILUS_LTE:

src/mainboard/google/poppy/variants/nautilus/memory.c

@@ -14,6 +14,7 @@
  */
 
 #include <baseboard/variants.h>
+#include <variant/sku.h>
 
 /* DQ byte map */
 static const u8 dq_map[][12] = {
@@ -46,4 +47,13 @@ void variant_memory_params(struct memory_params *p)
 	p->rcomp_resistor_size = sizeof(rcomp_resistor);
 	p->rcomp_target = rcomp_target;
 	p->rcomp_target_size = sizeof(rcomp_target);
+
+	switch (variant_board_sku()) {
+	case SKU_0_NAUTILUS:
+		/* Bumping VCC_SA voltage offset 75mV to allow a
+		 * tolerance to PLLGT on Nautilus-Wifi sku */
+		p->enable_sa_oc_support = 1;
+		p->sa_voltage_offset_val = 75;
+		break;
+	}
 }

src/mainboard/google/poppy/variants/nautilus/sku.c

@@ -0,0 +1,43 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2018 Google Inc.
+ *
+ * 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 <gpio.h>
+#include <variant/sku.h>
+
+uint32_t variant_board_sku(void)
+{
+#if ENV_ROMSTAGE
+	uint32_t sku_id = SKU_UNKNOWN;
+#else
+	static uint32_t sku_id = SKU_UNKNOWN;
+
+	if (sku_id != SKU_UNKNOWN)
+		return sku_id;
+#endif
+
+	/*
+	*  Nautilus uses GPP_B20 to determine SKU
+	*  0 - Wifi SKU
+	*  1 - LTE SKU
+	*/
+	gpio_input_pulldown(GPP_B20);
+	if (!gpio_get(GPP_B20))
+		sku_id = SKU_0_NAUTILUS;
+	else
+		sku_id = SKU_1_NAUTILUS_LTE;
+
+	return sku_id;
+}