source: rtems/bsps/arm/stm32h7/boards/stm/stm32h7b3i-dk/system_stm32h7xx.c @ d8017f20

/**
  ******************************************************************************
  * @file    system_stm32h7xx.c
  * @author  MCD Application Team
  * @brief   CMSIS Cortex-Mx Device Peripheral Access Layer System Source File.
  *
  *   This file provides two functions and one global variable to be called from
  *   user application:
  *      - SystemInit(): This function is called at startup just after reset and
  *                      before branch to main program. This call is made inside
  *                      the "startup_stm32h7xx.s" file.
  *
  *      - SystemCoreClock variable: Contains the core clock (HCLK), it can be used
  *                                  by the user application to setup the SysTick
  *                                  timer or configure other parameters.
  *
  *      - SystemCoreClockUpdate(): Updates the variable SystemCoreClock and must
  *                                 be called whenever the core clock is changed
  *                                 during program execution.
  *
  *
  ******************************************************************************
  * @attention
  *
  * Copyright (c) 2018 STMicroelectronics.
  * All rights reserved.
  *
  * This software is licensed under terms that can be found in the LICENSE file
  * in the root directory of this software component.
  * If no LICENSE file comes with this software, it is provided AS-IS.
  *
  ******************************************************************************
  */

/** @addtogroup CMSIS
  * @{
  */

/** @addtogroup stm32h7xx_system
  * @{
  */

/** @addtogroup STM32H7xx_System_Private_Includes
  * @{
  */

#include "stm32h7xx.h"
#include <math.h>
#ifdef __rtems__
#include <bsp/linker-symbols.h>
#endif /* __rtems__ */
#if !defined  (HSE_VALUE)
#define HSE_VALUE    ((uint32_t)24000000) /*!< Value of the External oscillator in Hz */
#endif /* HSE_VALUE */

#if !defined  (CSI_VALUE)
  #define CSI_VALUE    ((uint32_t)4000000) /*!< Value of the Internal oscillator in Hz*/
#endif /* CSI_VALUE */

#if !defined  (HSI_VALUE)
  #define HSI_VALUE    ((uint32_t)64000000) /*!< Value of the Internal oscillator in Hz*/
#endif /* HSI_VALUE */


/**
  * @}
  */

/** @addtogroup STM32H7xx_System_Private_TypesDefinitions
  * @{
  */

/**
  * @}
  */

/** @addtogroup STM32H7xx_System_Private_Defines
  * @{
  */

/************************* Miscellaneous Configuration ************************/
/*!< Uncomment the following line if you need to use initialized data in CD domain AHB SRAM */
/* #define DATA_IN_CD_AHB_SRAM */

/*!< Uncomment the following line if you need to relocate your vector Table in
     Internal SRAM. */
/* #define VECT_TAB_SRAM */
#define VECT_TAB_OFFSET  0x00000000UL /*!< Vector Table base offset field.
                                      This value must be a multiple of 0x200. */
/******************************************************************************/

/**
  * @}
  */

/** @addtogroup STM32H7xx_System_Private_Macros
  * @{
  */

/**
  * @}
  */

/** @addtogroup STM32H7xx_System_Private_Variables
  * @{
  */
  /* This variable is updated in three ways:
      1) by calling CMSIS function SystemCoreClockUpdate()
      2) by calling HAL API function HAL_RCC_GetHCLKFreq()
      3) each time HAL_RCC_ClockConfig() is called to configure the system clock frequency
         Note: If you use this function to configure the system clock; then there
               is no need to call the 2 first functions listed above, since SystemCoreClock
               variable is updated automatically.
  */
#ifndef __rtems__
  uint32_t SystemCoreClock = 64000000;
  uint32_t SystemD2Clock = 64000000;  /* AXI and AHBs Clock frequency */
#else /* __rtems__ */
  RTEMS_SECTION(".rtemsstack") uint32_t SystemCoreClock;
  RTEMS_SECTION(".rtemsstack") uint32_t SystemD2Clock;
#endif /* __rtems__ */
  const  uint8_t D1CorePrescTable[16] = {0, 0, 0, 0, 1, 2, 3, 4, 1, 2, 3, 4, 6, 7, 8, 9}; /* CPU Domain Core Prescaler Table */

/**
  * @}
  */

/** @addtogroup STM32H7xx_System_Private_FunctionPrototypes
  * @{
  */

/**
  * @}
  */

/** @addtogroup STM32H7xx_System_Private_Functions
  * @{
  */

/**
  * @brief  Setup the microcontroller system
  *         Initialize the FPU setting and  vector table location
  *         configuration.
  * @param  None
  * @retval None
  */
void SystemInit (void)
{
#ifdef DATA_IN_CD_AHB_SRAM
 __IO uint32_t tmpreg;
#endif /* DATA_IN_CD_AHB_SRAM */

  /* FPU settings ------------------------------------------------------------*/
  #if (__FPU_PRESENT == 1) && (__FPU_USED == 1)
    SCB->CPACR |= ((3UL << (10*2))|(3UL << (11*2)));  /* set CP10 and CP11 Full Access */
  #endif
  /* Reset the RCC clock configuration to the default reset state ------------*/
  /* Set HSION bit */
  RCC->CR |= RCC_CR_HSION;

  /* Reset CFGR register */
  RCC->CFGR = 0x00000000;

  /* Reset HSEON, CSSON , CSION,RC48ON, CSIKERON PLL1ON, PLL2ON and PLL3ON bits */
  RCC->CR &= 0xEAF6ED7FU;

  /* Reset CDCFGR1 register */
  RCC->CDCFGR1 = 0x00000000;

  /* Reset CDCFGR2 register */
  RCC->CDCFGR2 = 0x00000000;

  /* Reset SRDCFGR register */
  RCC->SRDCFGR = 0x00000000;

  /* Reset PLLCKSELR register */
  RCC->PLLCKSELR = 0x02020200;

  /* Reset PLLCFGR register */
  RCC->PLLCFGR = 0x01FF0000;
  /* Reset PLL1DIVR register */
  RCC->PLL1DIVR = 0x01010280;
  /* Reset PLL1FRACR register */
  RCC->PLL1FRACR = 0x00000000;

  /* Reset PLL2DIVR register */
  RCC->PLL2DIVR = 0x01010280;

  /* Reset PLL2FRACR register */

  RCC->PLL2FRACR = 0x00000000;
  /* Reset PLL3DIVR register */
  RCC->PLL3DIVR = 0x01010280;

  /* Reset PLL3FRACR register */
  RCC->PLL3FRACR = 0x00000000;

  /* Reset HSEBYP bit */
  RCC->CR &= 0xFFFBFFFFU;

  /* Disable all interrupts */
  RCC->CIER = 0x00000000;

#ifdef DATA_IN_CD_AHB_SRAM
  /* in case of initialized data in CD AHB SRAM, enable the CD AHB SRAM clock */
  RCC->AHB2ENR |= (RCC_AHB2ENR_AHBSRAM1EN | RCC_AHB2ENR_AHBSRAM2EN);
#ifndef __rtems__
  tmpreg = RCC->AHB2ENR;
  (void) tmpreg;
#else /* __rtems__ */
  RCC->AHB2ENR;
#endif /* __rtems__ */
#endif /* DATA_IN_CD_AHB_SRAM */

/*
   * Disable the FMC bank1 (enabled after reset).
   * This, prevents CPU speculation access on this bank which blocks the use of FMC during
   * 24us. During this time the others FMC master (such as LTDC) cannot use it!
   */
  FMC_Bank1_R->BTCR[0] = 0x000030D2;

#ifndef __rtems__
  /* Configure the Vector Table location add offset address for cortex-M7 ------------------*/
#ifdef VECT_TAB_SRAM
  SCB->VTOR = CD_AXISRAM1_BASE  | VECT_TAB_OFFSET; /* Vector Table Relocation in Internal CD AXI-RAM */
#else
  SCB->VTOR = FLASH_BANK1_BASE | VECT_TAB_OFFSET; /* Vector Table Relocation in Internal FLASH */
#endif
#else /* __rtems__ */
  SCB->VTOR = (uint32_t) bsp_start_vector_table_begin;
#endif /* __rtems__ */

}

/**
   * @brief  Update SystemCoreClock variable according to Clock Register Values.
  *         The SystemCoreClock variable contains the core clock , it can
  *         be used by the user application to setup the SysTick timer or configure
  *         other parameters.
  *
  * @note   Each time the core clock changes, this function must be called
  *         to update SystemCoreClock variable value. Otherwise, any configuration
  *         based on this variable will be incorrect.
  *
  * @note   - The system frequency computed by this function is not the real
  *           frequency in the chip. It is calculated based on the predefined
  *           constant and the selected clock source:
  *
  *           - If SYSCLK source is CSI, SystemCoreClock will contain the CSI_VALUE(*)
  *           - If SYSCLK source is HSI, SystemCoreClock will contain the HSI_VALUE(**)
  *           - If SYSCLK source is HSE, SystemCoreClock will contain the HSE_VALUE(***)
  *           - If SYSCLK source is PLL, SystemCoreClock will contain the CSI_VALUE(*),
  *             HSI_VALUE(**) or HSE_VALUE(***) multiplied/divided by the PLL factors.
  *
  *         (*) CSI_VALUE is a constant defined in stm32h7xx_hal.h file (default value
  *             4 MHz) but the real value may vary depending on the variations
  *             in voltage and temperature.
  *         (**) HSI_VALUE is a constant defined in stm32h7xx_hal.h file (default value
  *             64 MHz) but the real value may vary depending on the variations
  *             in voltage and temperature.
  *
  *         (***)HSE_VALUE is a constant defined in stm32h7xx_hal.h file (default value
  *              25 MHz), user has to ensure that HSE_VALUE is same as the real
  *              frequency of the crystal used. Otherwise, this function may
  *              have wrong result.
  *
  *         - The result of this function could be not correct when using fractional
  *           value for HSE crystal.
  * @param  None
  * @retval None
  */
void SystemCoreClockUpdate (void)
{
  uint32_t pllp, pllsource, pllm, pllfracen, hsivalue, tmp;
  float_t fracn1, pllvco;

  /* Get SYSCLK source -------------------------------------------------------*/

  switch (RCC->CFGR & RCC_CFGR_SWS)
  {
  case RCC_CFGR_SWS_HSI:  /* HSI used as system clock source */
    SystemCoreClock = (uint32_t) (HSI_VALUE >> ((RCC->CR & RCC_CR_HSIDIV)>> 3));
    break;

  case RCC_CFGR_SWS_CSI:  /* CSI used as system clock  source */
    SystemCoreClock = CSI_VALUE;
    break;

  case RCC_CFGR_SWS_HSE:  /* HSE used as system clock  source */
    SystemCoreClock = HSE_VALUE;
    break;

  case RCC_CFGR_SWS_PLL1:  /* PLL1 used as system clock  source */

    /* PLL_VCO = (HSE_VALUE or HSI_VALUE or CSI_VALUE/ PLLM) * PLLN
    SYSCLK = PLL_VCO / PLLR
    */
    pllsource = (RCC->PLLCKSELR & RCC_PLLCKSELR_PLLSRC);
    pllm = ((RCC->PLLCKSELR & RCC_PLLCKSELR_DIVM1)>> 4)  ;
    pllfracen = ((RCC->PLLCFGR & RCC_PLLCFGR_PLL1FRACEN)>>RCC_PLLCFGR_PLL1FRACEN_Pos);
    fracn1 = (float_t)(uint32_t)(pllfracen* ((RCC->PLL1FRACR & RCC_PLL1FRACR_FRACN1)>> 3));

    if (pllm != 0U)
    {
      switch (pllsource)
      {
        case RCC_PLLCKSELR_PLLSRC_HSI:  /* HSI used as PLL clock source */

        hsivalue = (HSI_VALUE >> ((RCC->CR & RCC_CR_HSIDIV)>> 3)) ;
        pllvco = ( (float_t)hsivalue / (float_t)pllm) * ((float_t)(uint32_t)(RCC->PLL1DIVR & RCC_PLL1DIVR_N1) + (fracn1/(float_t)0x2000) +(float_t)1 );

        break;

        case RCC_PLLCKSELR_PLLSRC_CSI:  /* CSI used as PLL clock source */
          pllvco = ((float_t)CSI_VALUE / (float_t)pllm) * ((float_t)(uint32_t)(RCC->PLL1DIVR & RCC_PLL1DIVR_N1) + (fracn1/(float_t)0x2000) +(float_t)1 );
        break;

        case RCC_PLLCKSELR_PLLSRC_HSE:  /* HSE used as PLL clock source */
          pllvco = ((float_t)HSE_VALUE / (float_t)pllm) * ((float_t)(uint32_t)(RCC->PLL1DIVR & RCC_PLL1DIVR_N1) + (fracn1/(float_t)0x2000) +(float_t)1 );
        break;

      default:
          pllvco = ((float_t)CSI_VALUE / (float_t)pllm) * ((float_t)(uint32_t)(RCC->PLL1DIVR & RCC_PLL1DIVR_N1) + (fracn1/(float_t)0x2000) +(float_t)1 );
        break;
      }
      pllp = (((RCC->PLL1DIVR & RCC_PLL1DIVR_P1) >>9) + 1U ) ;
      SystemCoreClock =  (uint32_t)(float_t)(pllvco/(float_t)pllp);
    }
    else
    {
      SystemCoreClock = 0U;
    }
    break;

  default:
    SystemCoreClock = CSI_VALUE;
    break;
  }

  /* Compute SystemClock frequency --------------------------------------------------*/

  tmp = D1CorePrescTable[(RCC->CDCFGR1 & RCC_CDCFGR1_CDCPRE)>> RCC_CDCFGR1_CDCPRE_Pos];

  /* SystemCoreClock frequency : CM7 CPU frequency  */
  SystemCoreClock >>= tmp;

  /* SystemD2Clock frequency : AXI and AHBs Clock frequency  */
  SystemD2Clock = (SystemCoreClock >> ((D1CorePrescTable[(RCC->CDCFGR1 & RCC_CDCFGR1_HPRE)>> RCC_CDCFGR1_HPRE_Pos]) & 0x1FU));

}


/**
  * @}
  */

/**
  * @}
  */

/**
  * @}
  */