idle, x86: Allow off-lined CPU to enter deeper C states

[mirror_ubuntu-bionic-kernel.git] / drivers / acpi / processor_idle.c

diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 0e8e2de2ed3e3a6b18ab07d07713a529295f31aa..6b1d32a161aefb4c5f3e39b9d386a8361a91718d 100644 (file)
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -770,6 +770,35 @@ static int acpi_idle_enter_c1(struct cpuidle_device *dev,
        return index;
 }
 
+
+/**
+ * acpi_idle_play_dead - enters an ACPI state for long-term idle (i.e. off-lining)
+ * @dev: the target CPU
+ * @index: the index of suggested state
+ */
+static int acpi_idle_play_dead(struct cpuidle_device *dev, int index)
+{
+       struct cpuidle_state_usage *state_usage = &dev->states_usage[index];
+       struct acpi_processor_cx *cx = cpuidle_get_statedata(state_usage);
+
+       ACPI_FLUSH_CPU_CACHE();
+
+       while (1) {
+
+               if (cx->entry_method == ACPI_CSTATE_HALT)
+                       halt();
+               else if (cx->entry_method == ACPI_CSTATE_SYSTEMIO) {
+                       inb(cx->address);
+                       /* See comment in acpi_idle_do_entry() */
+                       inl(acpi_gbl_FADT.xpm_timer_block.address);
+               } else
+                       return -ENODEV;
+       }
+
+       /* Never reached */
+       return 0;
+}
+
 /**
  * acpi_idle_enter_simple - enters an ACPI state without BM handling
  * @dev: the target CPU
@@ -1077,12 +1106,14 @@ static int acpi_processor_setup_cpuidle_states(struct acpi_processor *pr)
                                state->flags |= CPUIDLE_FLAG_TIME_VALID;
 
                        state->enter = acpi_idle_enter_c1;
+                       state->enter_dead = acpi_idle_play_dead;
                        drv->safe_state_index = count;
                        break;
 
                        case ACPI_STATE_C2:
                        state->flags |= CPUIDLE_FLAG_TIME_VALID;
                        state->enter = acpi_idle_enter_simple;
+                       state->enter_dead = acpi_idle_play_dead;
                        drv->safe_state_index = count;
                        break;