Upsilon/ion/src/device/shared/drivers/power.cpp

#include <ion/battery.h>
#include <ion/keyboard.h>
#include <ion/led.h>
#include <ion/usb.h>
#include <drivers/board.h>
#include <drivers/battery.h>
#include <drivers/external_flash.h>
#include <drivers/keyboard.h>
#include <drivers/led.h>
#include <drivers/power.h>
#include <drivers/usb.h>
#include <drivers/reset.h>
#include <drivers/wakeup.h>
#include <regs/regs.h>
#include <regs/config/pwr.h>
#include <regs/config/rcc.h>
#include "events_keyboard_platform.h"

namespace Ion {

namespace Power {

void suspend(bool checkIfOnOffKeyReleased) {
  bool isLEDActive = Ion::LED::getColor() != KDColorBlack;
  bool plugged = USB::isPlugged();

  if (checkIfOnOffKeyReleased) {
    Device::Power::waitUntilOnOffKeyReleased();
  }

  /* First, shutdown all peripherals except LED. Indeed, the charging pin state
   * might change when we shutdown peripherals that draw current. */
  Device::Board::shutdownPeripherals(true);

  while (1) {
    // Update LED color according to plug and charge state
    Device::Battery::initGPIO();
    Device::USB::initGPIO();
    Device::LED::init();
    isLEDActive = LED::updateColorWithPlugAndCharge() != KDColorBlack;

    // Configure low-power mode
    if (isLEDActive) {
      Device::Power::sleepConfiguration();
    } else {
      Device::Power::stopConfiguration();
    }

    // Shutdown all peripherals (except LED if active)
    Device::Board::shutdownPeripherals(isLEDActive);

    /* Wake up on:
     * - Power key
     * - Plug/Unplug USB
     * - Stop charging */
    Device::Power::configWakeUp();

    // Shutdown all clocks (except the ones used by LED if active)
    Device::Board::shutdownClocks(isLEDActive);

    Device::Power::enterLowPowerMode();

    /* A hardware event triggered a wake up, we determine if the device should
     * wake up. We wake up when:
     * - only the power key was down
     * - the unplugged device was plugged */
    Device::Board::initClocks();

    // Check power key
    Device::Keyboard::init();
    Keyboard::State scan = Keyboard::scan();
    Ion::Keyboard::State OnlyOnOffKeyDown = Keyboard::State(Keyboard::Key::OnOff);

    // Check plugging state
    Device::USB::initGPIO();
    if (scan == OnlyOnOffKeyDown || (!plugged && USB::isPlugged())) {
      // Wake up
      break;
    } else {
      /* The wake up event can be an unplug event or a battery charging event.
       * In both cases, we want to update static observed states like
       * sLastUSBPlugged or sLastBatteryCharging. */
      Events::getPlatformEvent();
    }
    plugged = USB::isPlugged();
  }

  // Reset normal frequency
  Device::Board::setStandardFrequency(Device::Board::Frequency::High);
  Device::Board::initClocks();
  Device::Board::initPeripherals(true);
  // Update LED according to plug and charge state
  LED::updateColorWithPlugAndCharge();
  /* If the USB has been unplugged while sleeping, the USB should have been
   * soft disabled but as part of the USB peripheral was asleep, this could
   * not be done before. */
  if (USB::isPlugged()) {
    USB::disable();
  }
}

}

}

namespace Ion {
namespace Device {
namespace Power {

// Public Power methods
using namespace Device::Regs;

void configWakeUp() {
  Device::WakeUp::onOnOffKeyDown();
  Device::WakeUp::onUSBPlugging();
  Device::WakeUp::onChargingEvent();
}

void stopConfiguration() {
  // This is done differently on the models
  PWR.CR()->setMRUDS(true); // Main regulator in Low Voltage and Flash memory in Deep Sleep mode when the device is in Stop mode
  PWR.CR()->setLPUDS(true); // Low-power regulator in under-drive mode if LPDS bit is set and Flash memory in power-down when the device is in Stop under-drive mode
  PWR.CR()->setLPDS(true); // Low-power Voltage regulator on. Takes longer to wake up.
  PWR.CR()->setFPDS(true); // Put the flash to sleep. Takes longer to wake up.
#if REGS_PWR_CONFIG_ADDITIONAL_FIELDS
  PWR.CR()->setUDEN(PWR::CR::UnderDrive::Enable);
#endif

  CORTEX.SCR()->setSLEEPDEEP(true);
}

void sleepConfiguration() {
  // Decrease HCLK frequency
  Device::Board::setStandardFrequency(Device::Board::Frequency::Low);
  Device::Board::setClockFrequency(Device::Board::standardFrequency());

#if REGS_PWR_CONFIG_ADDITIONAL_FIELDS
  // Disable over-drive
  PWR.CR()->setODSWEN(false);
  while(!PWR.CSR()->getODSWRDY()) {
  }
  PWR.CR()->setODEN(true);
#endif

  CORTEX.SCR()->setSLEEPDEEP(false);
}

void standbyConfiguration() {
  PWR.CR()->setPPDS(true); // Select standby when the CPU enters deepsleep
  PWR.CR()->setCSBF(true); // Clear Standby flag
  PWR.CSR()->setBRE(false); // Unable back up RAM (lower power consumption in standby)
  PWR.CSR()->setEIWUP(false); // Unable RTC (lower power consumption in standby)

  /* The pin A0 is about to be configured as a wakeup pin. However, the matrix
   * keyboard connects pin A0 (row B) with other pins (column 1, column 3...).
   * We thus shutdown this pins to avoid the potential pull-up on pin A0 due to
   * a keyboard event. For example, if the "Home" key is down, pin A0 is
   * pulled-up so enabling it as the wake up pin would trigger a wake up flag
   * instantly. */
  Device::Keyboard::shutdown();
#if REGS_PWR_CONFIG_ADDITIONAL_FIELDS
  PWR.CSR2()->setEWUP1(true); // Enable PA0 as wakeup pin
  PWR.CR2()->setWUPP1(false); // Define PA0 (wakeup) pin polarity (rising edge)
  PWR.CR2()->setCWUPF1(true); // Clear wakeup pin flag for PA0 (if device has already been in standby and woke up)
#endif

  CORTEX.SCR()->setSLEEPDEEP(true); // Allow Cortex-M7 deepsleep state
}

void waitUntilOnOffKeyReleased() {
  /* Wait until power is released to avoid restarting just after suspending */
  bool isPowerDown = true;
  while (isPowerDown) {
    Keyboard::State scan = Keyboard::scan();
    isPowerDown = scan.keyDown(Keyboard::Key::OnOff);
  }
  Timing::msleep(100);
}

void enterLowPowerMode() {
  /* To enter sleep, we need to issue a WFE instruction, which waits for the
   * event flag to be set and then clears it. However, the event flag might
   * already be on. So the safest way to make sure we actually wait for a new
   * event is to force the event flag to on (SEV instruction), use a first WFE
   * to clear it, and then a second WFE to wait for a _new_ event. */
  asm("sev");
  asm("wfe");
  asm("nop");
  asm("wfe");
}

}
}
}