text: /*******************************************************************************
   * Copyright (C) 2016 Maxim Integrated Products, Inc., All Rights Reserved.
   *
   * 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 MAXIM INTEGRATED 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.
   *
   * Except as contained in this notice, the name of Maxim Integrated
   * Products, Inc. shall not be used except as stated in the Maxim Integrated
   * Products, Inc. Branding Policy.
   *
   * The mere transfer of this software does not imply any licenses
   * of trade secrets, proprietary technology, copyrights, patents,
   * trademarks, maskwork rights, or any other form of intellectual
   * property whatsoever. Maxim Integrated Products, Inc. retains all
   * ownership rights.
   *******************************************************************************
   */
  
  #include "sleep_api.h"
  #include "pwrman_regs.h"
  #include "pwrseq_regs.h"
  #include "clkman_regs.h"
  #include "ioman_regs.h"
  #include "rtc_regs.h"
  #include "usb_regs.h"
  
  #define REVISION_A3 2
  #define REVISION_A4 3
  
  // USB state to be restored upon wakeup
  typedef struct {
      uint32_t dev_cn;
      uint32_t dev_inten;
      uint32_t ep_base;
      uint32_t ep[MXC_USB_NUM_EP];
  } usb_state_t;
  
  static mxc_uart_regs_t *stdio_uart = (mxc_uart_regs_t*)STDIO_UART;
  static int restore_usb;
  static usb_state_t usb_state;
  
  void hal_sleep(void)
  {
      // Normal sleep mode for ARM core
      SCB->SCR = 0;
  
      __DSB();
      __WFI();
  }
  
  static void usb_sleep(void)
  {
      int i;
  
      if (MXC_USB->cn & MXC_F_USB_CN_USB_EN) {
          // The USB module will not survive Deep Sleep.
  
          // Save the USB state to restore it upon wakeup
          usb_state.dev_cn = MXC_USB->dev_cn;
          usb_state.dev_inten = MXC_USB->dev_inten;
          usb_state.ep_base = MXC_USB->ep_base;
          for (i = 0; i < MXC_USB_NUM_EP; i++) {
              usb_state.ep[i] = MXC_USB->ep[i] & (MXC_F_USB_EP_DIR | MXC_F_USB_EP_BUF2 | MXC_F_USB_EP_INT_EN | MXC_F_USB_EP_NAK_EN);
          }
          restore_usb = 1;
  
          // Shut down the USB module.
          MXC_USB->dev_inten = 0;
          MXC_USB->dev_cn = 0;
          MXC_USB->cn = 0;
          restore_usb = 1;   // USB should be restored upon wakeup
      } else {
          restore_usb = 0;
      }
  }
  
  // Restore the USB module state.
  static void usb_wakeup(void)
  {
      int i;
  
      if (restore_usb) {
          MXC_USB->cn = MXC_F_USB_CN_USB_EN;
          MXC_USB->dev_cn = MXC_F_USB_DEV_CN_URST;
          MXC_USB->dev_cn = 0;
          for (i = 0; i < MXC_USB_NUM_EP; i++) {
              MXC_USB->ep[i] = usb_state.ep[i];
          }
          MXC_USB->ep_base = usb_state.ep_base;
          MXC_USB->dev_cn = usb_state.dev_cn;
          MXC_USB->dev_inten = usb_state.dev_inten;
          restore_usb = 0;
      }
  }
  
  // Low-power stop mode
  void hal_deepsleep(void)
  {
      unsigned int part_rev = MXC_PWRMAN->mask_id0 & MXC_F_PWRMAN_MASK_ID0_REVISION_ID;
  
      // Deep Sleep is not working properly on Revisions A3 and earlier
      if (part_rev <= REVISION_A3) {
          hal_sleep();
          return;
      }
  
      // Wait for all STDIO characters to be sent. The UART clock will stop.
      while ((stdio_uart->tx_fifo_ctrl & MXC_F_UART_TX_FIFO_CTRL_FIFO_ENTRY) ||
              !(stdio_uart->intfl & MXC_F_UART_INTFL_TX_DONE));
  
      __disable_irq();
  
      // Do not enter Deep Sleep if connected to VBUS
      if (MXC_USB->dev_intfl & MXC_F_USB_DEV_INTFL_VBUS_ST) {
          __enable_irq();
          hal_sleep();
          return;
      }
  
      // The USB module will not survive Deep Sleep. Shut it down.
      usb_sleep();
  
      // Make sure RTC is not pending before sleeping, if its still synchronizing
      // we might not wake up.
      while (MXC_RTCTMR->ctrl & MXC_F_RTC_CTRL_PENDING);
  
      // Clear any active GPIO Wake Up Events
      if (MXC_PWRSEQ->flags & MXC_F_PWRSEQ_FLAGS_PWR_IOWAKEUP) {
          // NOTE: These must be cleared before clearing IOWAKEUP
          MXC_PWRSEQ->reg1 |= MXC_F_PWRSEQ_REG1_PWR_CLR_IO_EVENT_LATCH;
          MXC_PWRSEQ->reg1 &= ~MXC_F_PWRSEQ_REG1_PWR_CLR_IO_EVENT_LATCH;
  
          MXC_PWRSEQ->flags |= MXC_F_PWRSEQ_FLAGS_PWR_IOWAKEUP;
      }
  
      // Set the LP1 select bit so CPU goes to LP1 during SLEEPDEEP
      if (part_rev == REVISION_A4) {
          MXC_PWRSEQ->reg0 &= ~MXC_F_PWRSEQ_REG0_PWR_LP1; // A4 requires part to go to pseudo LP0
      } else {
          MXC_PWRSEQ->reg0 |= MXC_F_PWRSEQ_REG0_PWR_LP1;
      }
  
      // The SLEEPDEEP bit will cause a WFE() to trigger LP0/LP1 (depending on ..._REG0_PWR_LP1 state)
      SCB->SCR |= SCB_SCR_SLEEPDEEP_Msk;
  
      if (part_rev == REVISION_A4) {
          // WORKAROUND: Toggle SVM bits, which send extra clocks to the power sequencer to fix retention controller
          MXC_PWRSEQ->msk_flags |= MXC_F_PWRSEQ_MSK_FLAGS_PWR_TVDD12_RST_BAD;
          MXC_PWRSEQ->reg0 &= ~(MXC_F_PWRSEQ_REG0_PWR_SVMTVDD12EN_RUN);
          MXC_PWRSEQ->reg0 |= MXC_F_PWRSEQ_REG0_PWR_SVMTVDD12EN_RUN;
          MXC_PWRSEQ->msk_flags &= ~MXC_F_PWRSEQ_MSK_FLAGS_PWR_TVDD12_RST_BAD;
      }
  
      // Enable Retention controller
      MXC_PWRSEQ->retn_ctrl0 |= MXC_F_PWRSEQ_RETN_CTRL0_RETN_CTRL_EN;
  
      // Clear the firstboot bit, which is generated by a POR event and locks out LPx modes
      MXC_PWRSEQ->reg0 &= ~MXC_F_PWRSEQ_REG0_PWR_FIRST_BOOT;
  
      // Freeze GPIO using MBUS so that it doesn't flail while digital core is asleep
      MXC_PWRSEQ->reg1 |= MXC_F_PWRSEQ_REG1_PWR_MBUS_GATE;
  
      // Dummy read to make sure SSB writes are complete
      MXC_PWRSEQ->reg0 = MXC_PWRSEQ->reg0;
  
      if (part_rev == REVISION_A4) {
          // Note: ARM deep-sleep requires a specific sequence to clear event latches,
          // otherwise the CPU will not enter sleep.
          __SEV();
          __WFE();
          __WFI();
      } else {
          // Note: ARM deep-sleep requires a specific sequence to clear event latches,
          //  otherwise the CPU will not enter sleep.
          __SEV();
          __WFE();
          __WFE();
      }
  
      // We'll wakeup here ...
  
      // Unfreeze the GPIO by clearing MBUS_GATE
      MXC_PWRSEQ->reg1 &= ~MXC_F_PWRSEQ_REG1_PWR_MBUS_GATE;
  
      usb_wakeup();
  
      // Clear power sequencer event flags (write-1-to-clear)
      // RTC and GPIO flags are cleared in their interrupts handlers
      // NOTE: We are ignoring all of these potential wake up types
      MXC_PWRSEQ->flags = (MXC_F_PWRSEQ_FLAGS_PWR_POWER_FAIL |
                           MXC_F_PWRSEQ_FLAGS_PWR_BOOT_FAIL |
                           MXC_F_PWRSEQ_FLAGS_PWR_FLASH_DISCHARGE |
                           MXC_F_PWRSEQ_FLAGS_PWR_VDD12_RST_BAD |
                           MXC_F_PWRSEQ_FLAGS_PWR_VDD18_RST_BAD |
                           MXC_F_PWRSEQ_FLAGS_PWR_VRTC_RST_BAD |
                           MXC_F_PWRSEQ_FLAGS_PWR_VDDB_RST_BAD |
                           MXC_F_PWRSEQ_FLAGS_PWR_TVDD12_RST_BAD |
                           MXC_F_PWRSEQ_FLAGS_PWR_POR18Z_FAIL_LATCH |
                           MXC_F_PWRSEQ_FLAGS_PWR_USB_PLUG_WAKEUP |
                           MXC_F_PWRSEQ_FLAGS_PWR_USB_REMOVE_WAKEUP |
                           MXC_F_PWRSEQ_FLAGS_PWR_TVDD12_BAD);
  
      __enable_irq();
  }
  