cheza: Enable AP_RST_REQ as a request from AP to reset itself

This makes the EC listen to the AP_RST_REQ GPIO from AP. The rising
edge interrupts to trigger a hook to call chipset_reset().

As the hook task will be preempted by the chipset task, it adds a
flag bypass_power_lost_trigger to avoid triggering to S5 as the
chipset state machines sees power lost during the reset.

So far the chipset_reset() implementation is to do a cold reset;
will be revised to a warm reset after the PMIC registers are
reprogrammed.

BRANCH=none
BUG=b:74395451
TEST=make buildall -j
TEST=Ran 'reboot' on AP console which toggles the GPIO.

Change-Id: I946cb029541ce018a8ed1ce25681d38998a7f4b6
Signed-off-by: Wai-Hong Tam <waihong@google.com>
Reviewed-on: https://chromium-review.googlesource.com/1023986
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>

4 files changed, 37 insertions, 2 deletions

diff --git a/board/cheza/board.c b/board/cheza/board.c
index c22c7c6d3e..e7862b9064 100644
--- a/board/cheza/board.c
+++ b/board/cheza/board.c
@@ -7,6 +7,7 @@
 
 #include "adc_chip.h"
 #include "button.h"
+#include "chipset.h"
 #include "extpower.h"
 #include "gpio.h"
 #include "hooks.h"
diff --git a/board/cheza/gpio.inc b/board/cheza/gpio.inc
index 8c89555bbc..85ea7a4a5f 100644
--- a/board/cheza/gpio.inc
+++ b/board/cheza/gpio.inc
@@ -13,6 +13,7 @@ GPIO_INT(VOLUME_DOWN_L,     PIN(7, 0), GPIO_INT_BOTH | GPIO_PULL_UP, button_inte
 GPIO_INT(VOLUME_UP_L,       PIN(1, 1), GPIO_INT_BOTH | GPIO_PULL_UP, button_interrupt)  /* EC_VOLUP_BTN_ODL */
 GPIO_INT(WP_L,              PIN(A, 1), GPIO_INT_BOTH, switch_interrupt)  /* EC_WP_ODL */
 GPIO_INT(LID_OPEN,          PIN(D, 2), GPIO_INT_BOTH, lid_interrupt)  /* LID_OPEN_EC */
+GPIO_INT(AP_RST_REQ,        PIN(C, 2), GPIO_INT_RISING | GPIO_PULL_DOWN, chipset_reset_request_interrupt)  /* Reset request from AP */
 /* AP_RST_L is used for PMIC and AP negotiation. Don't change its state. */
 GPIO_INT(AP_RST_L,          PIN(C, 1), GPIO_INT_BOTH, power_signal_interrupt)
 
@@ -30,7 +31,6 @@ GPIO(CCD_MODE_ODL,          PIN(E, 3), GPIO_INPUT)     /* Case Closed Debug Mode
 GPIO(BATT_PRES_ODL,         PIN(E, 5), GPIO_INPUT | GPIO_PULL_UP)  /* EC_BATT_PRES_ODL: Battery Present */
 GPIO(PMIC_FAULT_L,          PIN(7, 6), GPIO_INPUT)     /* Any PMIC fault? */
 GPIO(PMIC_KPD_PWR_ODL,      PIN(D, 6), GPIO_OUT_HIGH)  /* TP10, rework jumps to PMIC power button */
-GPIO(AP_RST_REQ,            PIN(C, 2), GPIO_INPUT)     /* Reset request from AP */
 GPIO(AP_EC_INT_L,           PIN(A, 2), GPIO_INPUT)     /* Interrupt line between AP and EC */
 
 /* Power enables */
diff --git a/include/chipset.h b/include/chipset.h
index ba78c45397..85d33425f8 100644
--- a/include/chipset.h
+++ b/include/chipset.h
@@ -121,4 +121,12 @@ int chipset_pltrst_is_valid(void) __attribute__((weak));
  * Execute chipset-specific reboot.
  */
 void chipset_handle_reboot(void);
+
+/**
+ * GPIO interrupt handler of reset request from AP.
+ *
+ * It is used in SDM845 chipset power sequence.
+ */
+void chipset_reset_request_interrupt(enum gpio_signal signal);
+
 #endif  /* __CROS_EC_CHIPSET_H */
diff --git a/power/sdm845.c b/power/sdm845.c
index fb3eb40efc..ded32ee64b 100644
--- a/power/sdm845.c
+++ b/power/sdm845.c
@@ -73,6 +73,14 @@ static char power_button_was_pressed;
 /* 1 if lid-open event has been detected */
 static char lid_opened;
 
+/*
+ * 1 if power state is controlled by special functions, like a console command
+ * or an interrupt handler, for bypassing POWER_GOOD lost trigger. It is
+ * because these functions control the PMIC and AP power signals directly and
+ * don't want to get preempted by the chipset state machine.
+ */
+static uint8_t bypass_power_lost_trigger;
+
 /* Time where we will power off, if power button still held down */
 static timestamp_t power_off_deadline;
 
@@ -116,6 +124,19 @@ enum power_on_event_t {
 	POWER_ON_EVENT_COUNT,
 };
 
+/* AP-requested reset GPIO interrupt handlers */
+static void chipset_reset_request_handler(void)
+{
+	CPRINTS("AP wants reset");
+	chipset_reset();
+}
+DECLARE_DEFERRED(chipset_reset_request_handler);
+
+void chipset_reset_request_interrupt(enum gpio_signal signal)
+{
+	hook_call_deferred(&chipset_reset_request_handler_data, 0);
+}
+
 static void sdm845_lid_event(void)
 {
 	/* Power task only cares about lid-open events */
@@ -257,6 +278,9 @@ enum power_state power_chipset_init(void)
 	int init_power_state;
 	uint32_t reset_flags = system_get_reset_flags();
 
+	/* Enable reboot control input from AP */
+	gpio_enable_interrupt(GPIO_AP_RST_REQ);
+
 	/*
 	 * Force the AP shutdown unless we are doing SYSJUMP. Otherwise,
 	 * the AP could stay in strange state.
@@ -444,7 +468,7 @@ static int check_for_power_off_event(void)
 	power_button_was_pressed = pressed;
 
 	/* POWER_GOOD released by AP : shutdown immediately */
-	if (!power_has_signals(IN_POWER_GOOD)) {
+	if (!power_has_signals(IN_POWER_GOOD) && !bypass_power_lost_trigger) {
 		if (power_button_was_pressed)
 			timer_cancel(TASK_ID_CHIPSET);
 
@@ -474,7 +498,9 @@ void chipset_reset(void)
 	 * reset pin and zero-latency. We do cold reset instead.
 	 */
 	CPRINTS("EC triggered cold reboot");
+	bypass_power_lost_trigger = 1;
 	power_off();
+	bypass_power_lost_trigger = 0;
 
 	/* Issue a request to initiate a power-on sequence */
 	power_request = POWER_REQ_ON;