charger: Change unlocked battery level ignore conditions

x86 systems will auto-power-on when power is applied to the EC. When
the battery level is critically low, power-on is prevented, except when
the system is unlocked. So, when unlocked, some systems will
auto-power-on regardless of battery level, overcurrent the charger /
battery, and then repeat forever.

Prevent this reboot loop by ignoring auto-power-up when the battery is
critically low, regardless of system unlocked status.

BUG=chrome-os-partner:48339
TEST=Verify power-up is prevented on no-battery chell w/ donette. Then,
run 'powerbtn' on EC console and verify system powers on (and
overcurrents).
BRANCH=None

Change-Id: Ia631b5a8c45b42ec805e4a0c3f827929a0efd236
Signed-off-by: Shawn Nematbakhsh <shawnn@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/319187
Commit-Ready: Shawn N <shawnn@chromium.org>
Tested-by: Shawn N <shawnn@chromium.org>
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>

8 files changed, 31 insertions, 26 deletions

diff --git a/board/samus/power_sequence.c b/board/samus/power_sequence.c
index a3e40338f4..cac9647a44 100644
--- a/board/samus/power_sequence.c
+++ b/board/samus/power_sequence.c
@@ -228,7 +228,7 @@ enum power_state power_handle_state(enum power_state state)
 	case POWER_G3S5:
 		/* Return to G3 if battery level is too low */
 		if (charge_want_shutdown() ||
-		    charge_prevent_power_on()) {
+		    charge_prevent_power_on(0)) {
 			CPRINTS("power-up inhibited");
 			chipset_force_g3();
 			return POWER_G3;
diff --git a/common/charge_state_v1.c b/common/charge_state_v1.c
index 4002901f76..b38bdc3e0d 100644
--- a/common/charge_state_v1.c
+++ b/common/charge_state_v1.c
@@ -682,7 +682,7 @@ int charge_want_shutdown(void)
 		charge_get_percent() < BATTERY_LEVEL_SHUTDOWN;
 }
 
-int charge_prevent_power_on(void)
+int charge_prevent_power_on(int power_button_pressed)
 {
 	int prevent_power_on = 0;
 #ifdef CONFIG_CHARGER_MIN_BAT_PCT_FOR_POWER_ON
diff --git a/common/charge_state_v2.c b/common/charge_state_v2.c
index c49fc639eb..4401aa54bb 100644
--- a/common/charge_state_v2.c
+++ b/common/charge_state_v2.c
@@ -644,8 +644,6 @@ void charger_task(void)
 			charger_set_input_current(curr.desired_input_current);
 		}
 
-		curr.chg.flags |= CHG_FLAG_INITIALIZED;
-
 		/*
 		 * TODO(crosbug.com/p/27527). Sometimes the battery thinks its
 		 * temperature is 6280C, which seems a bit high. Let's ignore
@@ -916,14 +914,20 @@ int charge_want_shutdown(void)
 		(curr.batt.state_of_charge < BATTERY_LEVEL_SHUTDOWN);
 }
 
-int charge_prevent_power_on(void)
+int charge_prevent_power_on(int power_button_pressed)
 {
 	int prevent_power_on = 0;
 #ifdef CONFIG_CHARGER_MIN_BAT_PCT_FOR_POWER_ON
 	struct batt_params params;
 	struct batt_params *current_batt_params = &curr.batt;
-	int charger_is_uninitialized =
-		!(curr.chg.flags & CHG_FLAG_INITIALIZED);
+	static int automatic_power_on = 1;
+
+	/*
+	 * Remember that a power button was pressed, and assume subsequent
+	 * power-ups are user-requested and non-automatic.
+	 */
+	if (power_button_pressed)
+		automatic_power_on = 0;
 
 	/* If battery params seem uninitialized then retrieve them */
 	if (current_batt_params->is_present == BP_NOT_SURE) {
@@ -951,9 +955,9 @@ int charge_prevent_power_on(void)
 
 	/*
 	 * Factory override: Always allow power on if WP is disabled,
-	 * except when EC is starting up, due to brown out potential.
+	 * except when auto-power-on at EC startup.
 	 */
-	prevent_power_on &= (system_is_locked() || charger_is_uninitialized);
+	prevent_power_on &= (system_is_locked() || automatic_power_on);
 #endif
 
 	return prevent_power_on;
diff --git a/common/lightbar.c b/common/lightbar.c
index 2355067016..822cb77caf 100644
--- a/common/lightbar.c
+++ b/common/lightbar.c
@@ -268,7 +268,7 @@ static int get_battery_level(void)
 #ifdef HAS_TASK_CHARGER
 	st.battery_percent = pct = charge_get_percent();
 	st.battery_is_charging = (PWR_STATE_DISCHARGE != charge_get_state());
-	st.battery_is_power_on_prevented = charge_prevent_power_on();
+	st.battery_is_power_on_prevented = charge_prevent_power_on(0);
 #endif
 
 	/* Find the new battery level */
diff --git a/common/power_button_x86.c b/common/power_button_x86.c
index 9ae2be1ff5..ce7bba990e 100644
--- a/common/power_button_x86.c
+++ b/common/power_button_x86.c
@@ -112,7 +112,7 @@ static const char * const state_names[] = {
  */
 static uint64_t tnext_state;
 
-static void set_pwrbtn_to_pch(int high)
+static void set_pwrbtn_to_pch(int high, int init)
 {
 	/*
 	 * If the battery is discharging and low enough we'd shut down the
@@ -122,7 +122,7 @@ static void set_pwrbtn_to_pch(int high)
 	 */
 #ifdef CONFIG_CHARGER
 	if (chipset_in_state(CHIPSET_STATE_ANY_OFF) && !high &&
-	   (charge_want_shutdown() || charge_prevent_power_on())) {
+	   (charge_want_shutdown() || charge_prevent_power_on(!init))) {
 		CPRINTS("PB PCH pwrbtn ignored due to battery level");
 		high = 1;
 	}
@@ -137,7 +137,7 @@ void power_button_pch_press(void)
 
 	/* Assert power button signal to PCH */
 	if (!power_button_is_pressed())
-		set_pwrbtn_to_pch(0);
+		set_pwrbtn_to_pch(0, 0);
 }
 
 void power_button_pch_release(void)
@@ -145,7 +145,7 @@ void power_button_pch_release(void)
 	CPRINTS("PB PCH force release");
 
 	/* Deassert power button signal to PCH */
-	set_pwrbtn_to_pch(1);
+	set_pwrbtn_to_pch(1, 0);
 
 	/*
 	 * If power button is actually pressed, eat the next release so we
@@ -162,7 +162,7 @@ void power_button_pch_pulse(void)
 	CPRINTS("PB PCH pulse");
 
 	chipset_exit_hard_off();
-	set_pwrbtn_to_pch(0);
+	set_pwrbtn_to_pch(0, 0);
 	pwrbtn_state = PWRBTN_STATE_LID_OPEN;
 	tnext_state = get_time().val + PWRBTN_INITIAL_US;
 	task_wake(TASK_ID_POWERBTN);
@@ -203,7 +203,7 @@ static void set_initial_pwrbtn_state(void)
 		 */
 		if (power_button_is_pressed()) {
 			CPRINTS("PB init-jumped-held");
-			set_pwrbtn_to_pch(0);
+			set_pwrbtn_to_pch(0, 0);
 		} else {
 			CPRINTS("PB init-jumped");
 		}
@@ -270,12 +270,12 @@ static void state_machine(uint64_t tnow)
 			tnext_state = tnow + PWRBTN_DELAY_T0;
 			pwrbtn_state = PWRBTN_STATE_T0;
 		}
-		set_pwrbtn_to_pch(0);
+		set_pwrbtn_to_pch(0, 0);
 		break;
 	case PWRBTN_STATE_T0:
 		tnext_state = tnow + PWRBTN_DELAY_T1;
 		pwrbtn_state = PWRBTN_STATE_T1;
-		set_pwrbtn_to_pch(1);
+		set_pwrbtn_to_pch(1, 0);
 		break;
 	case PWRBTN_STATE_T1:
 		/*
@@ -286,12 +286,12 @@ static void state_machine(uint64_t tnow)
 		if (chipset_in_state(CHIPSET_STATE_ANY_OFF))
 			CPRINTS("PB chipset already off");
 		else
-			set_pwrbtn_to_pch(0);
+			set_pwrbtn_to_pch(0, 0);
 		pwrbtn_state = PWRBTN_STATE_HELD;
 		break;
 	case PWRBTN_STATE_RELEASED:
 	case PWRBTN_STATE_LID_OPEN:
-		set_pwrbtn_to_pch(1);
+		set_pwrbtn_to_pch(1, 0);
 		pwrbtn_state = PWRBTN_STATE_IDLE;
 		break;
 	case PWRBTN_STATE_INIT_ON:
@@ -310,7 +310,7 @@ static void state_machine(uint64_t tnow)
 		 * battery is handled inside set_pwrbtn_to_pch().
 		 */
 		chipset_exit_hard_off();
-		set_pwrbtn_to_pch(0);
+		set_pwrbtn_to_pch(0, 1);
 		tnext_state = get_time().val + PWRBTN_INITIAL_US;
 
 		if (power_button_is_pressed()) {
@@ -329,7 +329,7 @@ static void state_machine(uint64_t tnow)
 		 * button until it's released, so that holding down the
 		 * recovery combination doesn't cause the chipset to shut back
 		 * down. */
-		set_pwrbtn_to_pch(1);
+		set_pwrbtn_to_pch(1, 0);
 		if (power_button_is_pressed())
 			pwrbtn_state = PWRBTN_STATE_EAT_RELEASE;
 		else
diff --git a/include/charge_state.h b/include/charge_state.h
index 97c6ca404e..3a86bf4baf 100644
--- a/include/charge_state.h
+++ b/include/charge_state.h
@@ -96,8 +96,11 @@ int charge_want_shutdown(void);
 /**
  * Return non-zero if the battery level is too low to allow power on, even if
  * a charger is attached.
+ *
+ * @param power_button_pressed	True if the power-up attempt is caused by a
+ *				power button press.
  */
-int charge_prevent_power_on(void);
+int charge_prevent_power_on(int power_button_pressed);
 
 /**
  * Get the last polled battery/charger temperature.
diff --git a/include/charger.h b/include/charger.h
index 70d0ff7543..3141c89bab 100644
--- a/include/charger.h
+++ b/include/charger.h
@@ -49,8 +49,6 @@ void charger_get_params(struct charger_params *chg);
 #define CHG_FLAG_BAD_INPUT_CURRENT	0x00000004
 #define CHG_FLAG_BAD_STATUS		0x00000008
 #define CHG_FLAG_BAD_OPTION		0x00000010
-/* Bit to indicate that the charger data has been initialized */
-#define CHG_FLAG_INITIALIZED		0x00000020
 /* All of the above CHG_FLAG_BAD_* bits */
 #define CHG_FLAG_BAD_ANY                0x0000001f
 
diff --git a/power/skylake.c b/power/skylake.c
index 8c28b6d42e..c15c26d1f7 100644
--- a/power/skylake.c
+++ b/power/skylake.c
@@ -198,7 +198,7 @@ static enum power_state _power_handle_state(enum power_state state)
 		 * Allow up to 1s for charger to be initialized, in case
 		 * we're trying to boot the AP with no battery.
 		 */
-		while (charge_prevent_power_on() &&
+		while (charge_prevent_power_on(0) &&
 		       tries++ < CHARGER_INITIALIZED_TRIES) {
 			msleep(CHARGER_INITIALIZED_DELAY_MS);
 		}