Volteer: add monitoring for PROCHOT input

Add monotoring of the PROCHOT input to the EC.

BUG=b:152340521
BRANCH=none
TEST=makebuild all
TEST=Assert PROCHOT output from the EC and confirm EC console logging or
PROCHOT input.

Signed-off-by: Keith Short <keithshort@chromium.org>
Change-Id: Ib28537a227ea40ac947f7b999a85354b1ae4c111
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2120067
Reviewed-by: Abe Levkoy <alevkoy@chromium.org>
Commit-Queue: Abe Levkoy <alevkoy@chromium.org>

baseboard/volteer/baseboard.c

@@ -661,6 +661,9 @@ static void baseboard_init(void)
 	 */
 	pwm_enable(PWM_CH_LED4_SIDESEL, 1);
 	pwm_set_duty(PWM_CH_LED4_SIDESEL, 50);
+
+	/* Enable monitoring of the PROCHOT input to the EC */
+	gpio_enable_interrupt(GPIO_EC_PROCHOT_IN_L);
 }
 DECLARE_HOOK(HOOK_INIT, baseboard_init, HOOK_PRIO_DEFAULT);
 

baseboard/volteer/baseboard.h

@@ -96,6 +96,7 @@
 #define CONFIG_THERMISTOR
 #define CONFIG_STEINHART_HART_3V3_30K9_47K_4050B
 #define CONFIG_THROTTLE_AP
+#define CONFIG_CHIPSET_CAN_THROTTLE
 
 /* Common charger defines */
 #define CONFIG_CHARGE_MANAGER

board/halvor/gpio.inc

@@ -94,6 +94,7 @@ GPIO(EC_PCH_RTCRST,            PIN(7, 6), GPIO_OUT_LOW)
 GPIO(EC_PCH_WAKE_ODL,          PIN(7, 4), GPIO_ODR_HIGH)
 GPIO(EC_ENTERING_RW,           PIN(E, 3), GPIO_OUT_LOW)
 GPIO(EC_PROCHOT_ODL,           PIN(6, 3), GPIO_ODR_HIGH)
+UNIMPLEMENTED(EC_PROCHOT_IN_L)
 GPIO(SYS_RST_ODL,              PIN(C, 5), GPIO_ODR_HIGH)
 
 GPIO(EC_PCH_INT_ODL,           PIN(B, 0), GPIO_ODR_HIGH)

board/malefor/gpio.inc

@@ -94,6 +94,7 @@ GPIO(EC_PCH_RTCRST,            PIN(7, 6), GPIO_OUT_LOW)
 GPIO(EC_PCH_WAKE_ODL,          PIN(7, 4), GPIO_ODR_HIGH)
 GPIO(EC_ENTERING_RW,           PIN(E, 3), GPIO_OUT_LOW)
 GPIO(EC_PROCHOT_ODL,           PIN(6, 3), GPIO_ODR_HIGH)
+UNIMPLEMENTED(EC_PROCHOT_IN_L)
 GPIO(SYS_RST_ODL,              PIN(C, 5), GPIO_ODR_HIGH)
 
 GPIO(EC_PCH_INT_ODL,           PIN(B, 0), GPIO_ODR_HIGH)

board/volteer/board.c

@@ -21,6 +21,7 @@
 #include "system.h"
 #include "task.h"
 #include "tablet_mode.h"
+#include "throttle_ap.h"
 #include "uart.h"
 #include "usb_pd_tbt.h"
 #include "util.h"

board/volteer/gpio.inc

@@ -94,6 +94,7 @@ GPIO(EC_PCH_RTCRST,            PIN(7, 6), GPIO_OUT_LOW)
 GPIO(EC_PCH_WAKE_ODL,          PIN(7, 4), GPIO_ODR_HIGH)
 GPIO(EC_ENTERING_RW,           PIN(E, 3), GPIO_OUT_LOW)
 GPIO(EC_PROCHOT_ODL,           PIN(6, 3), GPIO_ODR_HIGH)
+GPIO_INT(EC_PROCHOT_IN_L,      PIN(F, 0), GPIO_INT_BOTH, throttle_ap_prochot_input_interrupt)
 GPIO(SYS_RST_ODL,              PIN(C, 5), GPIO_ODR_HIGH)
 
 GPIO(EC_PCH_INT_ODL,           PIN(B, 0), GPIO_ODR_HIGH)

common/throttle_ap.c

@@ -8,19 +8,25 @@
 #include "chipset.h"
 #include "common.h"
 #include "console.h"
+#include "hooks.h"
 #include "host_command.h"
 #include "task.h"
 #include "throttle_ap.h"
+#include "timer.h"
 #include "util.h"
 
 /* Console output macros */
 #define CPUTS(outstr) cputs(CC_THERMAL, outstr)
 #define CPRINTS(format, args...) cprints(CC_THERMAL, format, ## args)
 
+#define PROCHOT_IN_DEBOUNCE_US		(100 * MSEC)
+
 /*****************************************************************************/
 /* This enforces the virtual OR of all throttling sources. */
 static struct mutex throttle_mutex;
 static uint32_t throttle_request[NUM_THROTTLE_TYPES];
+static int debounced_prochot_in;
+static enum gpio_signal gpio_prochot_in = GPIO_COUNT;
 
 void throttle_ap(enum throttle_level level,
 		 enum throttle_type type,
@@ -70,6 +76,50 @@ void throttle_ap(enum throttle_level level,
 
 }
 
+static void prochot_input_deferred(void)
+{
+	int prochot_in;
+
+	/*
+	 * Shouldn't be possible, but better to protect against buffer
+	 * overflow
+	 */
+	ASSERT(signal_is_gpio(gpio_prochot_in));
+
+	prochot_in = gpio_get_level(gpio_prochot_in);
+
+	if (IS_ENABLED(CONFIG_CPU_PROCHOT_ACTIVE_LOW))
+		prochot_in = !prochot_in;
+
+	if (prochot_in == debounced_prochot_in)
+		return;
+
+	debounced_prochot_in = prochot_in;
+
+	if (debounced_prochot_in)
+		CPRINTS("External PROCHOT assertion detected");
+	else
+		CPRINTS("External PROCHOT condition cleared");
+}
+DECLARE_DEFERRED(prochot_input_deferred);
+
+void throttle_ap_prochot_input_interrupt(enum gpio_signal signal)
+{
+	/*
+	 * Save the PROCHOT signal that generated the interrupt so we don't
+	 * rely on a specific pin name.
+	 */
+	if (gpio_prochot_in == GPIO_COUNT)
+		gpio_prochot_in = signal;
+
+	/*
+	 * Trigger deferred notification of PROCHOT change so we can ignore
+	 * any pulses that are too short.
+	 */
+	hook_call_deferred(&prochot_input_deferred_data,
+		PROCHOT_IN_DEBOUNCE_US);
+}
+
 /*****************************************************************************/
 /* Console commands */
 #ifdef CONFIG_CMD_APTHROTTLE

include/config.h

@@ -2948,6 +2948,8 @@
 
 /*
  * On x86 systems, define this option if the CPU_PROCHOT signal is active low.
+ * This setting also applies to monitoring the PROCHOT input if provided by
+ * the board.
  */
 #undef CONFIG_CPU_PROCHOT_ACTIVE_LOW
 

include/throttle_ap.h

@@ -52,6 +52,19 @@ void throttle_ap(enum throttle_level level,
 		 enum throttle_type type,
 		 enum throttle_sources source);
 
+/**
+ * Interrupt handler to monitor PROCHOT input to the EC. The PROCHOT signal
+ * can be asserted by the AP or by other devices on the board, such as chargers
+ * and voltage regulators.
+ *
+ * The board initialization is responsible for enabling the interrupt.
+ *
+ * @param signal    GPIO signal connected to PROCHOT input. The polarity of this
+ *                  signal is active high unless CONFIG_CPU_PROCHOT_ACTIVE_LOW
+ *                  is defined.
+ */
+void throttle_ap_prochot_input_interrupt(enum gpio_signal signal);
+
 #else
 static inline void throttle_ap(enum throttle_level level,
 			       enum throttle_type type,