static void __init intel_idle_init_cstates_icpu()

in intel_idle.c [1542:1602]

• 48 lines of code
• 19 McCabe index (conditional complexity)

static void __init intel_idle_init_cstates_icpu(struct cpuidle_driver *drv)
{
	int cstate;

	switch (boot_cpu_data.x86_model) {
	case INTEL_FAM6_IVYBRIDGE_X:
		ivt_idle_state_table_update();
		break;
	case INTEL_FAM6_ATOM_GOLDMONT:
	case INTEL_FAM6_ATOM_GOLDMONT_PLUS:
		bxt_idle_state_table_update();
		break;
	case INTEL_FAM6_SKYLAKE:
		sklh_idle_state_table_update();
		break;
	case INTEL_FAM6_SKYLAKE_X:
		skx_idle_state_table_update();
		break;
	}

	for (cstate = 0; cstate < CPUIDLE_STATE_MAX; ++cstate) {
		unsigned int mwait_hint;

		if (intel_idle_max_cstate_reached(cstate))
			break;

		if (!cpuidle_state_table[cstate].enter &&
		    !cpuidle_state_table[cstate].enter_s2idle)
			break;

		/* If marked as unusable, skip this state. */
		if (cpuidle_state_table[cstate].flags & CPUIDLE_FLAG_UNUSABLE) {
			pr_debug("state %s is disabled\n",
				 cpuidle_state_table[cstate].name);
			continue;
		}

		mwait_hint = flg2MWAIT(cpuidle_state_table[cstate].flags);
		if (!intel_idle_verify_cstate(mwait_hint))
			continue;

		/* Structure copy. */
		drv->states[drv->state_count] = cpuidle_state_table[cstate];

		if ((disabled_states_mask & BIT(drv->state_count)) ||
		    ((icpu->use_acpi || force_use_acpi) &&
		     intel_idle_off_by_default(mwait_hint) &&
		     !(cpuidle_state_table[cstate].flags & CPUIDLE_FLAG_ALWAYS_ENABLE)))
			drv->states[drv->state_count].flags |= CPUIDLE_FLAG_OFF;

		if (intel_idle_state_needs_timer_stop(&drv->states[drv->state_count]))
			drv->states[drv->state_count].flags |= CPUIDLE_FLAG_TIMER_STOP;

		drv->state_count++;
	}

	if (icpu->byt_auto_demotion_disable_flag) {
		wrmsrl(MSR_CC6_DEMOTION_POLICY_CONFIG, 0);
		wrmsrl(MSR_MC6_DEMOTION_POLICY_CONFIG, 0);
	}
}