soc/intel/cannonlake: Add devicetree setting to disable turbo

Introduce a new flag to disable turbo called 'cpu_turbo_disable'.
Keep the default and enable turbo on all platforms.

Change-Id: Ia23ce4d589b5ecc5515474eea52a40788ae3d3b5
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/50797
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by:  Felix Singer <felixsinger@posteo.net>

src/soc/intel/cannonlake/chip.h

@@ -439,6 +439,9 @@ struct soc_intel_cannonlake_config {
 	struct i915_gpu_panel_config panel_cfg;
 
 	struct i915_gpu_controller_info gfx;
+
+	/* Disable CPU Turbo in IA32_MISC_ENABLE */
+	bool cpu_turbo_disable;
 };
 
 typedef struct soc_intel_cannonlake_config config_t;

src/soc/intel/cannonlake/cpu.c

@@ -91,6 +91,8 @@ static void configure_c_states(void)
 /* All CPUs including BSP will run the following function. */
 void soc_core_init(struct device *cpu)
 {
+	config_t *cfg = config_of_soc();
+
 	/* Clear out pending MCEs */
 	/* TODO(adurbin): This should only be done on a cold boot. Also, some
 	 * of these banks are core vs package scope. For now every CPU clears
@@ -117,8 +119,10 @@ void soc_core_init(struct device *cpu)
 	/* Set energy policy */
 	set_energy_perf_bias(ENERGY_POLICY_NORMAL);
 
-	/* Enable Turbo */
-	enable_turbo();
+	if (cfg->cpu_turbo_disable)
+		disable_turbo();
+	else
+		enable_turbo();
 
 	/* Enable Vmx */
 	set_vmx_and_lock();