Power button state machine handles keyboard-controlled reset

On Power+ESC -> ignore the power button being down until it's
released; system stays powered down.

On Power+ESC+Refresh -> send a power button pulse to the PCH.  Ignore
the power button until after both the pulse has finished and the power
button is released.

Signed-off-by: Randall Spangler <rspangler@chromium.org>

BUG=chrome-os-partner:8723
TEST=manual

Reboot system.
Press power.
System powers on normally.

Hold down ESC, tap power very quickly.
System resets and stays off.

Hold down ESC and power for several seconds.
System resets and stays off.

Hold down ESC and refresh and tap power very quickly.
System powers on; EC console indicates it's in RO.

Hold down ESC and refresh and press power for ~100ms
System powers on; EC console indicates it's in RO.

Hold down ESC and refresh and press power for several seconds.
System powers on; EC console indicates it's in RO.

Hold down ESC and refresh and press power for at least 10 seconds.
System powers on; EC console indicates it's in RO.

Change-Id: Idf9619da54ab299b0c65e6d68abb5e35e2ce9c79

1 files changed, 61 insertions, 10 deletions

diff --git a/chip/lm4/power_button.c b/chip/lm4/power_button.c
index eb92c0284b..6ad2561a20 100644
--- a/chip/lm4/power_button.c
+++ b/chip/lm4/power_button.c
@@ -13,6 +13,7 @@
 #include "lpc.h"
 #include "lpc_commands.h"
 #include "power_button.h"
+#include "system.h"
 #include "task.h"
 #include "timer.h"
 #include "uart.h"
@@ -35,6 +36,9 @@
 #define PWRBTN_DEBOUNCE_US 30000  /* Debounce time for power button */
 #define PWRBTN_DELAY_T0    32000  /* 32ms (PCH requires >16ms) */
 #define PWRBTN_DELAY_T1    (4000000 - PWRBTN_DELAY_T0)  /* 4 secs - t0 */
+#define PWRBTN_RECOVERY_US 200000 /* Length of time to simulate power button
+				   * press when booting into
+				   * keyboard-controlled recovery mode */
 
 #define LID_DEBOUNCE_US    30000  /* Debounce time for lid switch */
 #define LID_PWRBTN_US      PWRBTN_DELAY_T0 /* Length of time to simulate power
@@ -47,6 +51,8 @@ enum power_button_state {
 	PWRBTN_STATE_T1,
 	PWRBTN_STATE_HELD_DOWN,
 	PWRBTN_STATE_STOPPING,
+	PWRBTN_STATE_BOOT_RESET,
+	PWRBTN_STATE_BOOT_RECOVERY,
 };
 static enum power_button_state pwrbtn_state = PWRBTN_STATE_STOPPED;
 
@@ -89,6 +95,13 @@ static void set_pwrbtn_to_pch(int high)
 }
 
 
+/* Return 1 if power button is pressed, 0 if not pressed. */
+static int get_power_button_pressed(void)
+{
+	return gpio_get_level(GPIO_POWER_BUTTONn) ? 0 : 1;
+}
+
+
 /* Power button state machine.  Passed current time from usec counter. */
 static void state_machine(uint64_t tnow)
 {
@@ -118,8 +131,13 @@ static void state_machine(uint64_t tnow)
 		set_pwrbtn_to_pch(1);
 		pwrbtn_state = PWRBTN_STATE_STOPPED;
 		break;
+	case PWRBTN_STATE_BOOT_RECOVERY:
+		set_pwrbtn_to_pch(1);
+		pwrbtn_state = PWRBTN_STATE_BOOT_RESET;
+		break;
 	case PWRBTN_STATE_STOPPED:
 	case PWRBTN_STATE_HELD_DOWN:
+	case PWRBTN_STATE_BOOT_RESET:
 		/* Do nothing */
 		break;
 	}
@@ -129,20 +147,33 @@ static void state_machine(uint64_t tnow)
 /* Handle debounced power button changing state */
 static void power_button_changed(uint64_t tnow)
 {
-	if (!gpio_get_level(GPIO_POWER_BUTTONn)) {
-		/* pressed */
+	if (pwrbtn_state == PWRBTN_STATE_BOOT_RECOVERY) {
+		/* Ignore all power button changes during the recovery pulse */
+		uart_printf("[%T PB changed during recovery pulse]\n");
+	} else if (get_power_button_pressed()) {
+		/* Power button pressed */
+		uart_printf("[%T PB pressed]\n");
 		pwrbtn_state = PWRBTN_STATE_START;
+		tnext_state = tnow;
 		*memmap_switches |= EC_LPC_SWITCH_POWER_BUTTON_PRESSED;
 		keyboard_set_power_button(1);
 		lpc_set_host_events(
 			EC_LPC_HOST_EVENT_MASK(EC_LPC_HOST_EVENT_POWER_BUTTON));
+	} else if (pwrbtn_state == PWRBTN_STATE_BOOT_RESET) {
+		/* Ignore the first power button release after a
+		 * keyboard-controlled reset, since we already told the PCH the
+		 * power button was released. */
+		uart_printf("[%T PB released after keyboard reset]\n");
+		pwrbtn_state = PWRBTN_STATE_STOPPED;
 	} else {
-		/* released */
+		/* Power button released normally (outside of a
+		 * keyboard-controlled reset) */
+		uart_printf("[%T PB released]\n");
 		pwrbtn_state = PWRBTN_STATE_STOPPING;
+		tnext_state = tnow;
 		*memmap_switches &= ~EC_LPC_SWITCH_POWER_BUTTON_PRESSED;
 		keyboard_set_power_button(0);
 	}
-	tnext_state = tnow;  /* Trigger next state transition now */
 }
 
 
@@ -203,14 +234,33 @@ int power_button_init(void)
 	/* Set up memory-mapped switch positions */
 	memmap_switches = lpc_get_memmap_range() + EC_LPC_MEMMAP_SWITCHES;
 	*memmap_switches = 0;
-	if (gpio_get_level(GPIO_POWER_BUTTONn) == 0)
-		*memmap_switches |= EC_LPC_SWITCH_POWER_BUTTON_PRESSED;
 	if (gpio_get_level(GPIO_LID_SWITCHn) != 0)
 		*memmap_switches |= EC_LPC_SWITCH_LID_OPEN;
 	update_other_switches();
 
-	/* Copy initial power button state to PCH */
-	gpio_set_level(GPIO_PCH_PWRBTNn, gpio_get_level(GPIO_POWER_BUTTONn));
+	if (system_get_reset_cause() == SYSTEM_RESET_RESET_PIN) {
+		/* Reset triggered by keyboard-controlled reset, so override
+		 * the power button signal to the PCH. */
+		if (keyboard_scan_recovery_pressed()) {
+			/* In recovery mode, so send a power button pulse to
+			 * the PCH so it powers on. */
+			set_pwrbtn_to_pch(0);
+			pwrbtn_state = PWRBTN_STATE_BOOT_RECOVERY;
+			tnext_state = get_time().val + PWRBTN_RECOVERY_US;
+		} else {
+			/* Keyboard-controlled reset, so don't let the PCH see
+			 * that the power button was pressed.  Otherwise, it
+			 * might power on. */
+			set_pwrbtn_to_pch(1);
+			pwrbtn_state = PWRBTN_STATE_BOOT_RESET;
+		}
+	} else {
+		/* Copy initial power button state to PCH and memory-mapped
+		 * switch positions. */
+		set_pwrbtn_to_pch(get_power_button_pressed() ? 0 : 1);
+		if (get_power_button_pressed())
+			*memmap_switches |= EC_LPC_SWITCH_POWER_BUTTON_PRESSED;
+	}
 
 	/* Enable interrupts, now that we've initialized */
 	gpio_enable_interrupt(GPIO_POWER_BUTTONn);
@@ -262,14 +312,15 @@ void power_button_task(void)
 			 * that can't happen - and even if it did, we'd just go
 			 * back to sleep after deciding that we woke up too
 			 * early.) */
-			uart_printf("[%T PB task wait %d]\n", d);
+			uart_printf("[%T PB task %d wait %d]\n",
+				    pwrbtn_state, d);
 			task_wait_msg(d);
 		}
 	}
 }
 
 /*****************************************************************************/
-/* Console commnands */
+/* Console commands */
 
 static int command_powerbtn(int argc, char **argv)
 {