/*
    ChibiOS/HAL - Copyright (C) 2006-2014 Giovanni Di Sirio

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

        http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
*/

/**
 * @file    STM32F0xx/hal_lld.c
 * @brief   STM32F0xx HAL subsystem low level driver source.
 *
 * @addtogroup HAL
 * @{
 */

#include "hal.h"

/*===========================================================================*/
/* Driver local definitions.                                                 */
/*===========================================================================*/

/*===========================================================================*/
/* Driver exported variables.                                                */
/*===========================================================================*/

/*===========================================================================*/
/* Driver local variables and types.                                         */
/*===========================================================================*/

/*===========================================================================*/
/* Driver local functions.                                                   */
/*===========================================================================*/

/**
 * @brief   Initializes the backup domain.
 * @note    WARNING! Changing clock source impossible without resetting
 *          of the whole BKP domain.
 */
static void hal_lld_backup_domain_init(void) {

  /* Backup domain access enabled and left open.*/
  PWR->CR |= PWR_CR_DBP;

  /* Reset BKP domain if different clock source selected.*/
  if ((RCC->BDCR & STM32_RTCSEL_MASK) != STM32_RTCSEL){
    /* Backup domain reset.*/
    RCC->BDCR = RCC_BDCR_BDRST;
    RCC->BDCR = 0;
  }

  /* If enabled then the LSE is started.*/
#if STM32_LSE_ENABLED
#if defined(STM32_LSE_BYPASS)
  /* LSE Bypass.*/
  RCC->BDCR |= STM32_LSEDRV | RCC_BDCR_LSEON | RCC_BDCR_LSEBYP;
#else
  /* No LSE Bypass.*/
  RCC->BDCR |= STM32_LSEDRV | RCC_BDCR_LSEON;
#endif
  while ((RCC->BDCR & RCC_BDCR_LSERDY) == 0)
    ;                                     /* Waits until LSE is stable.   */
#endif

#if STM32_RTCSEL != STM32_RTCSEL_NOCLOCK
  /* If the backup domain hasn't been initialized yet then proceed with
     initialization.*/
  if ((RCC->BDCR & RCC_BDCR_RTCEN) == 0) {
    /* Selects clock source.*/
    RCC->BDCR |= STM32_RTCSEL;

    /* RTC clock enabled.*/
    RCC->BDCR |= RCC_BDCR_RTCEN;
  }
#endif /* STM32_RTCSEL != STM32_RTCSEL_NOCLOCK */
}

/*===========================================================================*/
/* Driver interrupt handlers.                                                */
/*===========================================================================*/

/*===========================================================================*/
/* Driver exported functions.                                                */
/*===========================================================================*/

/**
 * @brief   Low level HAL driver initialization.
 *
 * @notapi
 */
void hal_lld_init(void) {

  /* Reset of all peripherals.*/
  rccResetAPB1(0xFFFFFFFF);
  rccResetAPB2(~RCC_APB2RSTR_DBGMCURST);

  /* PWR clock enabled.*/
  rccEnablePWRInterface(FALSE);

  /* Initializes the backup domain.*/
  hal_lld_backup_domain_init();

#if defined(STM32_DMA_REQUIRED)
  dmaInit();
#endif

  /* Programmable voltage detector enable.*/
#if STM32_PVD_ENABLE
  PWR->CR |= PWR_CR_PVDE | (STM32_PLS & STM32_PLS_MASK);
#endif /* STM32_PVD_ENABLE */
}

/**
 * @brief   STM32 clocks and PLL initialization.
 * @note    All the involved constants come from the file @p board.h.
 * @note    This function should be invoked just after the system reset.
 *
 * @special
 */
void stm32_clock_init(void) {

#if !STM32_NO_INIT
  /* HSI setup, it enforces the reset situation in order to handle possible
     problems with JTAG probes and re-initializations.*/
  RCC->CR |= RCC_CR_HSION;                  /* Make sure HSI is ON.         */
  while (!(RCC->CR & RCC_CR_HSIRDY))
    ;                                       /* Wait until HSI is stable.    */
  RCC->CR &= RCC_CR_HSITRIM | RCC_CR_HSION; /* CR Reset value.              */
  RCC->CFGR = 0;                            /* CFGR reset value.            */
  while ((RCC->CFGR & RCC_CFGR_SWS) != RCC_CFGR_SWS_HSI)
    ;                                       /* Waits until HSI is selected. */

#if STM32_HSE_ENABLED
  /* HSE activation.*/
#if defined(STM32_HSE_BYPASS)
  /* HSE Bypass.*/
  RCC->CR |= RCC_CR_HSEON | RCC_CR_HSEBYP;
#else
  /* No HSE Bypass.*/
  RCC->CR |= RCC_CR_HSEON;
#endif
  while (!(RCC->CR & RCC_CR_HSERDY))
    ;                                       /* Waits until HSE is stable.   */
#endif

#if STM32_HSE14_ENABLED
  /* HSI14 activation.*/
  RCC->CR2 |= RCC_CR2_HSI14ON;
  while (!(RCC->CR2 & RCC_CR2_HSI14RDY))
    ;                                       /* Waits until HSI14 is stable. */
#endif

#if STM32_LSI_ENABLED
  /* LSI activation.*/
  RCC->CSR |= RCC_CSR_LSION;
  while ((RCC->CSR & RCC_CSR_LSIRDY) == 0)
    ;                                       /* Waits until LSI is stable.   */
#endif

  /* Clock settings.*/
  RCC->CFGR  = STM32_MCOSEL | STM32_PLLMUL | STM32_PLLSRC |
               STM32_ADCPRE | STM32_PPRE   | STM32_HPRE;
  RCC->CFGR2 = STM32_PREDIV;
  RCC->CFGR3 = STM32_ADCSW  | STM32_CECSW  | STM32_I2C1SW |
               STM32_USART1SW;

#if STM32_ACTIVATE_PLL
  /* PLL activation.*/
  RCC->CR   |= RCC_CR_PLLON;
  while (!(RCC->CR & RCC_CR_PLLRDY))
    ;                                       /* Waits until PLL is stable.   */
#endif

  /* Flash setup and final clock selection.   */
  FLASH->ACR = STM32_FLASHBITS;

  /* Switching to the configured clock source if it is different from HSI.*/
#if (STM32_SW != STM32_SW_HSI)
  /* Switches clock source.*/
  RCC->CFGR |= STM32_SW;
  while ((RCC->CFGR & RCC_CFGR_SWS) != (STM32_SW << 2))
    ;                                       /* Waits selection complete.    */
#endif

  /* SYSCFG clock enabled here because it is a multi-functional unit shared
     among multiple drivers.*/
  rccEnableAPB2(RCC_APB2ENR_SYSCFGEN, TRUE);
#endif /* !STM32_NO_INIT */
}

/** @} */
