soc/intel/apollolake: Disable Monitor and Mwait feature

Monitor/Mwait is broken on APL. So, it needs to be disabled.

BUG=chrome-os-partner:56922
BRANCH=None

Change-Id: I12cd4280de62e0a639b43538171660ee4c0a0265
Signed-off-by: Venkateswarlu Vinjamuri <venkateswarlu.v.vinjamuri@intel.com>
Reviewed-on: https://review.coreboot.org/17200
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins)

src/include/cpu/intel/turbo.h

@@ -21,6 +21,9 @@
 #define PM_CAP_TURBO_MODE	(1 << 1)
 
 #define MSR_IA32_MISC_ENABLES	0x1a0
+/* Disable the Monitor Mwait FSM feature */
+#define MONITOR_MWAIT_DIS_MASK	0x40000
+
 #define H_MISC_DISABLE_TURBO	(1 << 6)
 
 enum {

src/soc/intel/apollolake/cpu.c

@@ -29,6 +29,7 @@
 #include <soc/cpu.h>
 #include <soc/iomap.h>
 #include <soc/smm.h>
+#include <cpu/intel/turbo.h>
 
 static const struct reg_script core_msr_script[] = {
 	/* Enable C-state and IO/MWAIT redirect */
@@ -40,6 +41,8 @@ static const struct reg_script core_msr_script[] = {
 		(ACPI_PMIO_CST_REG | (PMG_IO_BASE_CST_RNG_BLK_SIZE << 16))),
 	/* Disable C1E */
 	REG_MSR_RMW(MSR_POWER_CTL, ~0x2, 0),
+	/* Disable support for MONITOR and MWAIT instructions */
+	REG_MSR_RMW(MSR_IA32_MISC_ENABLES, ~MONITOR_MWAIT_DIS_MASK, 0),
 	REG_SCRIPT_END
 };