soc/intel/cannonlake: Add back PM TIMER EMULATION

ACPI PM timer emulation will be added back as default FSP stops TCO count
for power saving, which will also stop ACPI PM timer within PCH. CPU PM TIMER
EMULATION will help UEFI payload pass, instead of endless loop wait for
ACPI PM timer counter to increase.

BUG=N/A
TEST=Build and boot up fine with whiskey lake rvp board into UEFI shell.

Change-Id: Ie069e815e6244c3f85fabf51e186311621d316fd
Signed-off-by: Lijian Zhao <lijian.zhao@intel.com>
Reviewed-on: https://review.coreboot.org/28937
Reviewed-by: Furquan Shaikh <furquan@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/intel/cannonlake/cpu.c

@@ -1,7 +1,7 @@
 /*
  * This file is part of the coreboot project.
  *
- * Copyright (C) 2017 Intel Corporation.
+ * Copyright (C) 2017-2018 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
@@ -166,6 +166,27 @@ static void configure_c_states(void)
 	wrmsr(MSR_C_STATE_LATENCY_CONTROL_5, msr);
 }
 
+/*
+ * The emulated ACPI timer allows replacing of the ACPI timer
+ * (PM1_TMR) to have no impart on the system.
+ */
+static void enable_pm_timer_emulation(void)
+{
+	/* ACPI PM timer emulation */
+	msr_t msr;
+	/*
+	 * The derived frequency is calculated as follows:
+	 *    (CTC_FREQ * msr[63:32]) >> 32 = target frequency.
+	 * Back solve the multiplier so the 3.579545MHz ACPI timer
+	 * frequency is used.
+	 */
+	msr.hi = (3579545ULL << 32) / CTC_FREQ;
+	/* Set PM1 timer IO port and enable*/
+	msr.lo = (EMULATE_DELAY_VALUE << EMULATE_DELAY_OFFSET_VALUE) |
+			EMULATE_PM_TMR_EN | (ACPI_BASE_ADDRESS + PM1_TMR);
+	wrmsr(MSR_EMULATE_PM_TMR, msr);
+}
+
 /* All CPUs including BSP will run the following function. */
 void soc_core_init(struct device *cpu)
 {
@@ -188,6 +209,9 @@ void soc_core_init(struct device *cpu)
 	/* Configure Intel Speed Shift */
 	configure_isst();
 
+	/* Enable ACPI Timer Emulation via MSR 0x121 */
+	enable_pm_timer_emulation();
+
 	/* Enable Direct Cache Access */
 	configure_dca_cap();
 

src/soc/intel/cannonlake/include/soc/cpu.h

@@ -37,6 +37,9 @@
 #define C9_POWER	0xc8
 #define C10_POWER	0xc8
 
+/* Common Timer Copy (CTC) frequency - 24MHz. */
+#define CTC_FREQ		24000000
+
 #define C_STATE_LATENCY_MICRO_SECONDS(limit, base) \
 	(((1 << ((base)*5)) * (limit)) / 1000)
 #define C_STATE_LATENCY_FROM_LAT_REG(reg) \

src/soc/intel/common/block/include/intelblocks/msr.h

@@ -36,6 +36,7 @@
 #define MSR_EMULATE_PM_TMR	0x121
 #define   EMULATE_DELAY_OFFSET_VALUE	20
 #define   EMULATE_PM_TMR_EN	(1 << 16)
+#define   EMULATE_DELAY_VALUE	0x13
 #define MSR_FEATURE_CONFIG	0x13c
 #define   FEATURE_CONFIG_RESERVED_MASK	0x3ULL
 #define   FEATURE_CONFIG_LOCK	(1 << 0)