Implement fake and true deep sleep alarm differentiation

Author: hierophect

ports/stm/common-hal/alarm/__init__.c

@@ -39,11 +39,7 @@
 #include "supervisor/port.h"
 #include "supervisor/shared/workflow.h"
 
-#define STM_WAKEUP_UNDEF    0
-#define STM_WAKEUP_GPIO     1
-#define STM_WAKEUP_RTC      2
-
-#define STM_ALARM_FLAG      RTC->BKP0R
+STATIC uint8_t true_deep_wake_reason;
 
 void alarm_reset(void) {
     // Reset the alarm flag
@@ -54,6 +50,12 @@ void alarm_reset(void) {
     // esp_sleep_disable_wakeup_source(ESP_SLEEP_WAKEUP_ALL);
 }
 
+// Kind of a hack, required as RTC is reset in port.c
+// TODO: in the future, don't reset it at all, just override critical flags
+void alarm_set_wakeup_reason(uint8_t reason) {
+    true_deep_wake_reason = reason;
+}
+
 STATIC uint8_t _get_wakeup_cause(void) {
     // If in light/fake sleep, check modules
     if (alarm_pin_pinalarm_woke_us_up()) {
@@ -62,14 +64,9 @@ STATIC uint8_t _get_wakeup_cause(void) {
     if (alarm_time_timealarm_woke_us_up()) {
         return STM_WAKEUP_RTC;
     }
-    if (RTC->BKP0R & 0x01) {
-        // We've woken from deep sleep. Was it the WKUP pin or the RTC?
-        if (RTC->ISR & RTC_FLAG_ALRBF) {
-            // Alarm B is the deep sleep alarm
-            return STM_WAKEUP_RTC;
-        } else {
-            return STM_WAKEUP_GPIO;
-        }
+    // Check to see if we woke from deep sleep (reason set in port_init)
+    if (true_deep_wake_reason) {
+        return true_deep_wake_reason;
     }
     return STM_WAKEUP_UNDEF;
 }
@@ -160,6 +157,19 @@ void NORETURN common_hal_alarm_enter_deep_sleep(void) {
     while(1);
 }
 
+void common_hal_alarm_pretending_deep_sleep(void) {
+    // Re-enable the WKUP pin (PA00) since VM cleanup resets it
+    // If there are no PinAlarms, EXTI won't be turned on, and this won't do anything
+    // TODO: replace with `prepare_for_fake_deep_sleep` if other WKUP are added.
+    GPIO_InitTypeDef GPIO_InitStruct = {0};
+    GPIO_InitStruct.Pin = pin_mask(0);
+    GPIO_InitStruct.Mode = GPIO_MODE_IT_RISING;
+    GPIO_InitStruct.Pull = GPIO_PULLDOWN;
+    HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
+
+    port_idle_until_interrupt();
+}
+
 void common_hal_alarm_gc_collect(void) {
     gc_collect_ptr(shared_alarm_get_wake_alarm());
 }

ports/stm/common-hal/alarm/__init__.h

@@ -31,6 +31,13 @@
 
 const alarm_sleep_memory_obj_t alarm_sleep_memory_obj;
 
+#define STM_WAKEUP_UNDEF    0
+#define STM_WAKEUP_GPIO     1
+#define STM_WAKEUP_RTC      2
+
+#define STM_ALARM_FLAG      RTC->BKP0R
+
+extern void alarm_set_wakeup_reason(uint8_t reason);
 extern void alarm_reset(void);
 
 #endif // MICROPY_INCLUDED_STM32_COMMON_HAL_ALARM__INIT__H

ports/stm/common-hal/alarm/pin/PinAlarm.c

@@ -36,6 +36,7 @@ STATIC bool woke_up;
 
 STATIC uint16_t alarm_pin_triggered;
 STATIC bool deep_wkup_enabled;
+STATIC bool reserved_alarms[STM32_GPIO_PORT_SIZE];
 
 STATIC void pin_alarm_callback(uint8_t num) {
     alarm_pin_triggered |= (1 << num);
@@ -50,7 +51,6 @@ void common_hal_alarm_pin_pinalarm_construct(alarm_pin_pinalarm_obj_t *self, con
     if (!stm_peripherals_exti_is_free(pin->number)) {
         mp_raise_RuntimeError(translate("Pin interrupt already in use"));
     }
-    stm_peripherals_exti_reserve(pin->number);
     GPIO_InitTypeDef GPIO_InitStruct = {0};
     GPIO_InitStruct.Pin = pin_mask(pin->number);
     GPIO_InitStruct.Mode = value ? GPIO_MODE_IT_RISING : GPIO_MODE_IT_FALLING;
@@ -63,8 +63,7 @@ void common_hal_alarm_pin_pinalarm_construct(alarm_pin_pinalarm_obj_t *self, con
     }
     HAL_GPIO_Init(pin_port(pin->port), &GPIO_InitStruct);
 
-    stm_peripherals_exti_set_callback(pin_alarm_callback,pin->number);
-
+    // EXTI is set up and enabled in set_alarm
     self->pin = pin;
     self->value = value;
     self->pull = pull;
@@ -101,10 +100,11 @@ mp_obj_t alarm_pin_pinalarm_get_wakeup_alarm(size_t n_alarms, const mp_obj_t *al
         }
     }
 
-    // Placeholder for deep sleep
+    // If the above isn't true, we woke from deep sleep, so create a new alarm
     alarm_pin_pinalarm_obj_t *alarm = m_new_obj(alarm_pin_pinalarm_obj_t);
     alarm->base.type = &alarm_pin_pinalarm_type;
-    alarm->pin = NULL;
+    // TODO: replace this if/when other WKUP pins are supported
+    alarm->pin = &pin_PA00;
     return alarm;
 }
 
@@ -113,6 +113,12 @@ void alarm_pin_pinalarm_reset(void) {
     alarm_pin_triggered = 0;
     woke_up = false;
     deep_wkup_enabled = false;
+    for (uint8_t i = 0; i < STM32_GPIO_PORT_SIZE; i++) {
+        if (reserved_alarms[i]) {
+            stm_peripherals_exti_reset_exti(i);
+            reserved_alarms[i] = false;
+        }
+    }
 }
 
 // Deep sleep alarms don't actually make use of EXTI, but we pretend they're the same.
@@ -124,14 +130,24 @@ void alarm_pin_pinalarm_set_alarms(bool deep_sleep, size_t n_alarms, const mp_ob
                 // Deep sleep only wakes on a rising edge from one pin, WKUP (PA00)
                 // All pin settings are handled automatically.
                 if (alarm->pin != &pin_PA00) {
-                    mp_raise_ValueError(translate("Only the WKUP pin can be used to wake from Deep Sleep"));
+                    mp_raise_ValueError(translate("Pin cannot wake from Deep Sleep"));
+                }
+                if (alarm->value == false || alarm->pull == false) {
+                    // Enabling WakeUp automatically sets this, but warn anyway to set expectations
+                    mp_raise_ValueError(translate("Deep sleep pins must use a rising edge with pulldown"));
                 }
                 // We can't actually turn WakeUp on here, since enabling it disables EXTI,
                 // so we put it off until right before sleeping.
                 deep_wkup_enabled = true;
+                // EXTI needs to persist past the VM cleanup for fake deep sleep
+                stm_peripherals_exti_never_reset(alarm->pin->number);
             }
-
+            if (!stm_peripherals_exti_reserve(alarm->pin->number)) {
+                mp_raise_RuntimeError(translate("Pin interrupt already in use"));
+            }
+            stm_peripherals_exti_set_callback(pin_alarm_callback,alarm->pin->number);
             stm_peripherals_exti_enable(alarm->pin->number);
+            reserved_alarms[alarm->pin->number] = true;
         }
     }
 }

ports/stm/peripherals/exti.c

@@ -33,16 +33,30 @@
 #include "peripherals/exti.h"
 
 STATIC bool stm_exti_reserved[STM32_GPIO_PORT_SIZE];
+STATIC bool stm_exti_never_reset[STM32_GPIO_PORT_SIZE];
 STATIC void (*stm_exti_callback[STM32_GPIO_PORT_SIZE])(uint8_t num);
 
 void exti_reset(void) {
     for (size_t i = 0;i < STM32_GPIO_PORT_SIZE; i++) {
-        stm_exti_reserved[i] = false;
-        stm_exti_callback[i] = NULL;
-        stm_peripherals_exti_disable(i);
+        if (!stm_exti_never_reset[i]) {
+            stm_exti_reserved[i] = false;
+            stm_exti_callback[i] = NULL;
+            stm_peripherals_exti_disable(i);
+        }
     }
 }
 
+void stm_peripherals_exti_never_reset(uint8_t num) {
+    stm_exti_never_reset[num] = true;
+}
+
+void stm_peripherals_exti_reset_exti(uint8_t num) {
+    stm_peripherals_exti_disable(num);
+    stm_exti_never_reset[num] = false;
+    stm_exti_reserved[num] = false;
+    stm_exti_callback[num] = NULL;
+}
+
 bool stm_peripherals_exti_is_free(uint8_t num) {
     return !stm_exti_reserved[num];
 }

ports/stm/peripherals/exti.h

@@ -32,6 +32,8 @@
 #define STM32_GPIO_PORT_SIZE 16
 
 void exti_reset(void);
+void stm_peripherals_exti_never_reset(uint8_t num);
+void stm_peripherals_exti_reset_exti(uint8_t num);
 bool stm_peripherals_exti_is_free(uint8_t num);
 bool stm_peripherals_exti_reserve(uint8_t num);
 void stm_peripherals_exti_enable(uint8_t num);

ports/stm/peripherals/rtc.c

@@ -154,7 +154,7 @@ void stm32_peripherals_rtc_disable_wakeup_timer(void) {
     HAL_RTCEx_DeactivateWakeUpTimer(&hrtc);
 }
 
-void stm32_peripherals_reset_alarms(void) {
+void stm32_peripherals_rtc_reset_alarms(void) {
     HAL_RTC_DeactivateAlarm(&hrtc, RTC_ALARM_A);
     HAL_RTC_DeactivateAlarm(&hrtc, RTC_ALARM_B);
 }

ports/stm/peripherals/rtc.h

@@ -43,7 +43,7 @@ void stm32_peripherals_rtc_set_wakeup_mode_tick(void);
 void stm32_peripherals_rtc_enable_wakeup_timer(void);
 void stm32_peripherals_rtc_disable_wakeup_timer(void);
 
-void stm32_peripherals_reset_alarms(void);
+void stm32_peripherals_rtc_reset_alarms(void);
 void stm32_peripherals_rtc_assign_alarm_callback(uint8_t alarm_idx, void(*callback)(void)) ;
 void stm32_peripherals_rtc_set_alarm(uint8_t alarm_idx, uint32_t ticks);
 bool stm32_peripherals_rtc_alarm_triggered(uint8_t alarm_idx);

ports/stm/supervisor/port.c

@@ -53,6 +53,9 @@
 #if CIRCUITPY_PULSEIO || CIRCUITPY_ALARM
 #include "peripherals/exti.h"
 #endif
+#if CIRCUITPY_ALARM
+#include "common-hal/alarm/__init__.h"
+#endif
 
 #include "peripherals/clocks.h"
 #include "peripherals/gpio.h"
@@ -170,8 +173,18 @@ safe_mode_t port_init(void) {
     __HAL_RCC_SYSCFG_CLK_ENABLE();
 
     __HAL_RCC_PWR_CLK_ENABLE();
-
     HAL_PWR_EnableBkUpAccess();
+
+    // TODO: don't reset RTC entirely and move this back to alarm
+    if (STM_ALARM_FLAG & 0x01) {
+        // We've woken from deep sleep. Was it the WKUP pin or the RTC?
+        if (RTC->ISR & RTC_FLAG_ALRBF) {
+            // Alarm B is the deep sleep alarm
+            alarm_set_wakeup_reason(STM_WAKEUP_RTC);
+        } else {
+            alarm_set_wakeup_reason(STM_WAKEUP_GPIO);
+        }
+    }
     __HAL_RCC_BACKUPRESET_FORCE();
     __HAL_RCC_BACKUPRESET_RELEASE();
 
@@ -180,7 +193,7 @@ safe_mode_t port_init(void) {
     stm32_peripherals_rtc_init();
 
     __HAL_PWR_CLEAR_FLAG(PWR_FLAG_WU);
-    stm32_peripherals_reset_alarms();
+    stm32_peripherals_rtc_reset_alarms();
 
     // Turn off SysTick
     SysTick->CTRL = 0;