soc/intel/skylake: Add option to enable/disable EIST
Set MSR 0x1A0 bit[16] based on EIST config option.
Default Hardware Managed P-state (HWP) also known as Intel Speed Shift
is enabled on SKL hence disable EIST and ACPI P-state table.
Change-Id: I2b7374a8a04b596edcc88165b64980b7aa09e2a7
Signed-off-by: Subrata Banik <subrata.banik@intel.com>
Reviewed-on: https://review.coreboot.org/19676
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
diff --git a/src/soc/intel/skylake/acpi.c b/src/soc/intel/skylake/acpi.c
index e8d0c16..64438bd 100644
--- a/src/soc/intel/skylake/acpi.c
+++ b/src/soc/intel/skylake/acpi.c
@@ -523,9 +523,10 @@
generate_c_state_entries(is_s0ix_enable,
max_c_state);
- /* Generate P-state tables */
- generate_p_state_entries(core_id,
- cores_per_package);
+ if (config->eist_enable)
+ /* Generate P-state tables */
+ generate_p_state_entries(core_id,
+ cores_per_package);
acpigen_pop_len();
}
diff --git a/src/soc/intel/skylake/chip.h b/src/soc/intel/skylake/chip.h
index b474ca2..43c921e 100644
--- a/src/soc/intel/skylake/chip.h
+++ b/src/soc/intel/skylake/chip.h
@@ -459,6 +459,12 @@
/* Enable SGX feature */
u8 sgx_enable;
+
+ /* Enable/Disable EIST
+ * 1b - Enabled
+ * 0b - Disabled
+ */
+ u8 eist_enable;
};
typedef struct soc_intel_skylake_config config_t;
diff --git a/src/soc/intel/skylake/chip_fsp20.c b/src/soc/intel/skylake/chip_fsp20.c
index 2d9b864..8a7cb21 100644
--- a/src/soc/intel/skylake/chip_fsp20.c
+++ b/src/soc/intel/skylake/chip_fsp20.c
@@ -261,6 +261,9 @@
/* Enable PMC XRAM read */
tconfig->PchPmPmcReadDisable = config->PchPmPmcReadDisable;
+ /* Enable/Disable EIST */
+ tconfig->Eist = config->eist_enable;
+
soc_irq_settings(params);
}
diff --git a/src/soc/intel/skylake/cpu.c b/src/soc/intel/skylake/cpu.c
index c472617..0572413 100644
--- a/src/soc/intel/skylake/cpu.c
+++ b/src/soc/intel/skylake/cpu.c
@@ -245,12 +245,17 @@
static void configure_misc(void)
{
+ device_t dev = SA_DEV_ROOT;
+ config_t *conf = dev->chip_info;
msr_t msr;
msr = rdmsr(IA32_MISC_ENABLE);
msr.lo |= (1 << 0); /* Fast String enable */
msr.lo |= (1 << 3); /* TM1/TM2/EMTTM enable */
- msr.lo |= (1 << 16); /* Enhanced SpeedStep Enable */
+ if (conf->eist_enable)
+ msr.lo |= (1 << 16); /* Enhanced SpeedStep Enable */
+ else
+ msr.lo &= ~(1 << 16); /* Enhanced SpeedStep Disable */
wrmsr(IA32_MISC_ENABLE, msr);
/* Disable Thermal interrupts */