text: /*
   * This file is part of the MicroPython project, http://micropython.org/
   *
   * The MIT License (MIT)
   *
   * Copyright (c) 2021 Lucian Copeland for Adafruit Industries
   *
   * Permission is hereby granted, free of charge, to any person obtaining a copy
   * of this software and associated documentation files (the "Software"), to deal
   * in the Software without restriction, including without limitation the rights
   * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   * copies of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in
   * all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
   * THE SOFTWARE.
   */
  
  #include "py/gc.h"
  #include "py/obj.h"
  #include "py/objtuple.h"
  #include "py/runtime.h"
  
  #include "shared-bindings/alarm/__init__.h"
  #include "shared-bindings/alarm/SleepMemory.h"
  #include "shared-bindings/alarm/pin/PinAlarm.h"
  #include "shared-bindings/alarm/time/TimeAlarm.h"
  #include "shared-bindings/microcontroller/__init__.h"
  #include "shared/runtime/interrupt_char.h"
  #include "samd/external_interrupts.h"
  #include "supervisor/port.h"
  #include "supervisor/workflow.h"
  
  // Singleton instance of SleepMemory.
  const alarm_sleep_memory_obj_t alarm_sleep_memory_obj = {
      .base = {
          .type = &alarm_sleep_memory_type,
      },
  };
  // TODO: make a custom enum to avoid weird values like PM_SLEEPCFG_SLEEPMODE_BACKUP_Val?
  STATIC volatile uint32_t _target;
  STATIC bool fake_sleep;
  STATIC bool pin_wake;
  
  void alarm_reset(void) {
      // Reset the alarm flag
      SAMD_ALARM_FLAG = 0x00;
      alarm_pin_pinalarm_reset();
      alarm_time_timealarm_reset();
  }
  
  samd_sleep_source_t alarm_get_wakeup_cause(void) {
      // If in light/fake sleep, check modules
      if (alarm_pin_pinalarm_woke_this_cycle()) {
          return SAMD_WAKEUP_GPIO;
      }
      if (alarm_time_timealarm_woke_this_cycle()) {
          return SAMD_WAKEUP_RTC;
      }
      if (!fake_sleep && RSTC->RCAUSE.bit.BACKUP) {
          // This is checked during rtc_init to cache TAMPID if necessary
          if (pin_wake || RTC->MODE0.TAMPID.reg) {
              pin_wake = true;
              return SAMD_WAKEUP_GPIO;
          }
          return SAMD_WAKEUP_RTC;
      }
      return SAMD_WAKEUP_UNDEF;
  }
  
  bool common_hal_alarm_woken_from_sleep(void) {
      return alarm_get_wakeup_cause() != SAMD_WAKEUP_UNDEF;
  }
  
  mp_obj_t common_hal_alarm_create_wake_alarm(void) {
      // If woken from deep sleep, create a copy alarm similar to what would have
      // been passed in originally. Otherwise, just return none
      samd_sleep_source_t cause = alarm_get_wakeup_cause();
      switch (cause) {
          case SAMD_WAKEUP_RTC: {
              return alarm_time_timealarm_create_wakeup_alarm();
          }
          case SAMD_WAKEUP_GPIO: {
              return alarm_pin_pinalarm_create_wakeup_alarm();
          }
          case SAMD_WAKEUP_UNDEF:
          default:
              // Not a deep sleep reset.
              break;
      }
      return mp_const_none;
  }
  
  // Set up light sleep or deep sleep alarms.
  STATIC void _setup_sleep_alarms(bool deep_sleep, size_t n_alarms, const mp_obj_t *alarms) {
      alarm_pin_pinalarm_set_alarms(deep_sleep, n_alarms, alarms);
      alarm_time_timealarm_set_alarms(deep_sleep, n_alarms, alarms);
      fake_sleep = false;
  }
  
  mp_obj_t common_hal_alarm_light_sleep_until_alarms(size_t n_alarms, const mp_obj_t *alarms) {
      _setup_sleep_alarms(false, n_alarms, alarms);
      mp_obj_t wake_alarm = mp_const_none;
  
      while (!mp_hal_is_interrupted()) {
          RUN_BACKGROUND_TASKS;
          // Detect if interrupt was alarm or ctrl-C interrupt.
          if (common_hal_alarm_woken_from_sleep()) {
              samd_sleep_source_t cause = alarm_get_wakeup_cause();
              switch (cause) {
                  case SAMD_WAKEUP_RTC: {
                      wake_alarm = alarm_time_timealarm_find_triggered_alarm(n_alarms,alarms);
                      break;
                  }
                  case SAMD_WAKEUP_GPIO: {
                      wake_alarm = alarm_pin_pinalarm_find_triggered_alarm(n_alarms,alarms);
                      break;
                  }
                  default:
                      // Should not reach this, if all light sleep types are covered correctly
                      break;
              }
              shared_alarm_save_wake_alarm(wake_alarm);
              break;
          }
          // ATTEMPT ------------------------------
          // This works but achieves same power consumption as time.sleep()
  
          // Clear the FPU interrupt because it can prevent us from sleeping.
          if (__get_FPSCR() & ~(0x9f)) {
              __set_FPSCR(__get_FPSCR() & ~(0x9f));
              (void)__get_FPSCR();
          }
  
          // Disable RTC interrupts
          NVIC_DisableIRQ(RTC_IRQn);
          // Set standby power domain stuff
          PM->STDBYCFG.reg = PM_STDBYCFG_RAMCFG_OFF;
          // Set-up Sleep Mode
          PM->SLEEPCFG.reg = PM_SLEEPCFG_SLEEPMODE_STANDBY;
          while (PM->SLEEPCFG.bit.SLEEPMODE != PM_SLEEPCFG_SLEEPMODE_STANDBY_Val) {
              ;
          }
  
          __DSB(); // Data Synchronization Barrier
          __WFI(); // Wait For Interrupt
          // Enable RTC interrupts
          NVIC_EnableIRQ(RTC_IRQn);
          // END ATTEMPT ------------------------------
      }
      if (mp_hal_is_interrupted()) {
          return mp_const_none; // Shouldn't be given to python code because exception handling should kick in.
      }
  
      alarm_reset();
      return wake_alarm;
  }
  
  void common_hal_alarm_set_deep_sleep_alarms(size_t n_alarms, const mp_obj_t *alarms) {
      _setup_sleep_alarms(true, n_alarms, alarms);
  }
  
  void NORETURN common_hal_alarm_enter_deep_sleep(void) {
      alarm_pin_pinalarm_prepare_for_deep_sleep();
      alarm_time_timealarm_prepare_for_deep_sleep();
      _target = RTC->MODE0.COMP[1].reg;
      port_disable_tick(); // TODO: Required for SAMD?
  
      // cache alarm flag since backup registers about to be reset
      uint32_t _SAMD_ALARM_FLAG = SAMD_ALARM_FLAG;
  
      // Clear the FPU interrupt because it can prevent us from sleeping.
      if (__get_FPSCR() & ~(0x9f)) {
          __set_FPSCR(__get_FPSCR() & ~(0x9f));
          (void)__get_FPSCR();
      }
  
      NVIC_DisableIRQ(RTC_IRQn);
      // Must disable the RTC before writing to EVCTRL and TMPCTRL
      RTC->MODE0.CTRLA.bit.ENABLE = 0;                     // Disable the RTC
      while (RTC->MODE0.SYNCBUSY.bit.ENABLE) {             // Wait for synchronization
          ;
      }
      RTC->MODE0.CTRLA.bit.SWRST = 1;                      // Software reset the RTC
      while (RTC->MODE0.SYNCBUSY.bit.SWRST) {              // Wait for synchronization
          ;
      }
      RTC->MODE0.CTRLA.reg = RTC_MODE0_CTRLA_PRESCALER_DIV1024 |   // Set prescaler to 1024
          RTC_MODE0_CTRLA_MODE_COUNT32;                            // Set RTC to mode 0, 32-bit timer
  
      // Check if we're setting TimeAlarm
      if (_SAMD_ALARM_FLAG & SAMD_ALARM_FLAG_TIME) {
          RTC->MODE0.COMP[1].reg = (_target / 1024) * 32;
          while (RTC->MODE0.SYNCBUSY.reg) {
              ;
          }
      }
      // Check if we're setting PinAlarm
      if (_SAMD_ALARM_FLAG & SAMD_ALARM_FLAG_PIN) {
          RTC->MODE0.TAMPCTRL.bit.DEBNC2 = 1;  // Edge triggered when INn is stable for 4 CLK_RTC_DEB periods
          RTC->MODE0.TAMPCTRL.bit.TAMLVL2 = 1; // rising edge
          // PA02 = IN2
          RTC->MODE0.TAMPCTRL.bit.IN2ACT = 1;  // WAKE on IN2 (doesn't save timestamp)
      }
      // Enable interrupts
      NVIC_SetPriority(RTC_IRQn, 0);
      NVIC_EnableIRQ(RTC_IRQn);
      if (_SAMD_ALARM_FLAG & SAMD_ALARM_FLAG_TIME) {
          // Set interrupts for COMPARE1
          RTC->MODE0.INTENSET.reg = RTC_MODE0_INTENSET_CMP1;
      }
      if (_SAMD_ALARM_FLAG & SAMD_ALARM_FLAG_PIN) {
          // Set interrupts for TAMPER pins
          RTC->MODE0.INTENSET.reg = RTC_MODE0_INTENSET_TAMPER;
      }
  
      // Set-up Deep Sleep Mode & RAM retention
      PM->BKUPCFG.reg = PM_BKUPCFG_BRAMCFG(0x2);       // No RAM retention 0x2 partial:0x1
      while (PM->BKUPCFG.bit.BRAMCFG != 0x2) {         // Wait for synchronization
          ;
      }
      PM->SLEEPCFG.reg = PM_SLEEPCFG_SLEEPMODE_BACKUP;
      while (PM->SLEEPCFG.bit.SLEEPMODE != PM_SLEEPCFG_SLEEPMODE_BACKUP_Val) {
          ;
      }
      RTC->MODE0.CTRLA.bit.ENABLE = 1;                      // Enable the RTC
      while (RTC->MODE0.SYNCBUSY.bit.ENABLE) {              // Wait for synchronization
          ;
      }
  
      __DSB(); // Data Synchronization Barrier
      __WFI(); // Wait For Interrupt
  
      // The above shuts down RAM and triggers a reset, so we should never hit this
      while (1) {
          ;
      }
  }
  
  void common_hal_alarm_pretending_deep_sleep(void) {
      // TODO:
      //      If tamper detect interrupts cannot be used to wake from the Idle tier of sleep,
      //      This section will need to re-initialize the pins to allow the PORT peripheral
      //      to generate external interrupts again. See STM32 for reference.
  
      if (!fake_sleep) {
          fake_sleep = true;
      }
  }
  
  void common_hal_alarm_gc_collect(void) {
      gc_collect_ptr(shared_alarm_get_wake_alarm());
  }
  