intel_idle: Refactor intel_idle_cpuidle_driver_init()

Move the C-state verification and checks from
intel_idle_cpuidle_driver_init() to a separate function,
intel_idle_verify_cstate(), and make the former call it after
checking the CPUIDLE_FLAG_UNUSABLE state flag.

Also combine the drv->states[] updates with the incrementation of
drv->state_count.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c
index 75fd2a7..47255d3 100644 (file)
--- a/drivers/idle/intel_idle.c
+++ b/drivers/idle/intel_idle.c
@@ -944,6 +944,22 @@ static void intel_idle_s2idle(struct cpuidle_device *dev,
        mwait_idle_with_hints(eax, ecx);
 }
 
+static bool intel_idle_verify_cstate(unsigned int mwait_hint)
+{
+       unsigned int mwait_cstate = MWAIT_HINT2CSTATE(mwait_hint) + 1;
+       unsigned int num_substates = (mwait_substates >> mwait_cstate * 4) &
+                                       MWAIT_SUBSTATE_MASK;
+
+       /* Ignore the C-state if there are NO sub-states in CPUID for it. */
+       if (num_substates == 0)
+               return false;
+
+       if (mwait_cstate > 2 && !boot_cpu_has(X86_FEATURE_NONSTOP_TSC))
+               mark_tsc_unstable("TSC halts in idle states deeper than C2");
+
+       return true;
+}
+
 static void __setup_broadcast_timer(bool on)
 {
        if (on)
@@ -1332,10 +1348,10 @@ static void __init intel_idle_cpuidle_driver_init(void)
        drv->state_count = 1;
 
        for (cstate = 0; cstate < CPUIDLE_STATE_MAX; ++cstate) {
-               int num_substates, mwait_hint, mwait_cstate;
+               unsigned int mwait_hint;
 
-               if ((cpuidle_state_table[cstate].enter == NULL) &&
-                   (cpuidle_state_table[cstate].enter_s2idle == NULL))
+               if (!cpuidle_state_table[cstate].enter &&
+                   !cpuidle_state_table[cstate].enter_s2idle)
                        break;
 
                if (cstate + 1 > max_cstate) {
@@ -1343,34 +1359,19 @@ static void __init intel_idle_cpuidle_driver_init(void)
                        break;
                }
 
-               mwait_hint = flg2MWAIT(cpuidle_state_table[cstate].flags);
-               mwait_cstate = MWAIT_HINT2CSTATE(mwait_hint);
-
-               /* number of sub-states for this state in CPUID.MWAIT */
-               num_substates = (mwait_substates >> ((mwait_cstate + 1) * 4))
-                                       & MWAIT_SUBSTATE_MASK;
-
-               /* if NO sub-states for this state in CPUID, skip it */
-               if (num_substates == 0)
-                       continue;
-
-               /* if state marked as disabled, skip it */
+               /* 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;
 
-               if (((mwait_cstate + 1) > 2) &&
-                       !boot_cpu_has(X86_FEATURE_NONSTOP_TSC))
-                       mark_tsc_unstable("TSC halts in idle"
-                                       " states deeper than C2");
-
-               drv->states[drv->state_count] = /* structure copy */
-                       cpuidle_state_table[cstate];
-
-               drv->state_count += 1;
+               /* Structure copy. */
+               drv->states[drv->state_count++] = cpuidle_state_table[cstate];
        }
 
        if (icpu->byt_auto_demotion_disable_flag) {