gd32450i-eval/app/driver/STM32F4xx_HAL_Driver/system_stm32f4xx.c

/**
  ******************************************************************************
  * @file    system_stm32f4xx.c
  * @author  MCD Application Team
  * @brief   CMSIS Cortex-M4 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_stm32f4xx.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
  *
  * <h2><center>&copy; COPYRIGHT 2017 STMicroelectronics</center></h2>
  *
  * Redistribution and use in source and binary forms, with or without modification,
  * are permitted provided that the following conditions are met:
  *   1. Redistributions of source code must retain the above copyright notice,
  *      this list of conditions and the following disclaimer.
  *   2. Redistributions in binary form must reproduce the above copyright notice,
  *      this list of conditions and the following disclaimer in the documentation
  *      and/or other materials provided with the distribution.
  *   3. Neither the name of STMicroelectronics nor the names of its contributors
  *      may be used to endorse or promote products derived from this software
  *      without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  ******************************************************************************
  */

/** @addtogroup CMSIS
  * @{
  */

/** @addtogroup stm32f4xx_system
  * @{
  */  
  
/** @addtogroup STM32F4xx_System_Private_Includes
  * @{
  */


#include "stm32f4xx.h"
#include <linux/kernel.h>

#if !defined  (HSE_VALUE) 
  #define HSE_VALUE    ((uint32_t)25000000) /*!< Default value of the External oscillator in Hz */
#endif /* HSE_VALUE */

#if !defined  (HSI_VALUE)
  #define HSI_VALUE    ((uint32_t)16000000) /*!< Value of the Internal oscillator in Hz*/
#endif /* HSI_VALUE */


/*!< Uncomment the following line if you need to relocate your vector Table in
     Internal SRAM. */
/* #define VECT_TAB_SRAM */
#define VECT_TAB_OFFSET  0x00 /*!< Vector Table base offset field. 
                                   This value must be a multiple of 0x200. */
/******************************************************************************/

/**
  * @}
  */

/** @addtogroup STM32F4xx_System_Private_Macros
  * @{
  */

/**
  * @}
  */

/** @addtogroup STM32F4xx_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.
  */
uint32_t SystemCoreClock = 180000000;
const uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};
const uint8_t APBPrescTable[8]  = {0, 0, 0, 0, 1, 2, 3, 4};

/**
  * @brief  Setup the microcontroller system
  *         Initialize the FPU setting, vector table location and External memory 
  *         configuration.
  * @param  None
  * @retval None
  */
void SystemInit(void)
{
	/* u-boot/include/configs/stm32f429-discovery.h 
		HSE = 25000000;
		M	= 15
		N	= 216;
		P	= 2;
		Q	= don't care;
		SystemCoreClock = 180000000;
		u-boot/cpu/arm_cortexm3/stm32/clock.c
		APB1	= 45000000;
		APB2	= 90000000;
	   */
}

/**
   * @brief  Update SystemCoreClock variable according to Clock Register Values.
  *         The SystemCoreClock variable contains the core clock (HCLK), it can
  *         be used by the user application to setup the SysTick timer or configure
  *         other parameters.
  *           
  * @note   Each time the core clock (HCLK) 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 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 HSE_VALUE(**) 
  *             or HSI_VALUE(*) multiplied/divided by the PLL factors.
  *         
  *         (*) HSI_VALUE is a constant defined in stm32f4xx_hal_conf.h file (default value
  *             16 MHz) but the real value may vary depending on the variations
  *             in voltage and temperature.   
  *    
  *         (**) HSE_VALUE is a constant defined in stm32f4xx_hal_conf.h file (its value
  *              depends on the application requirements), 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 tmp = 0, pllvco = 0, pllp = 2, pllsource = 0, pllm = 2;
//  
//  /* Get SYSCLK source -------------------------------------------------------*/
//  tmp = RCC->CFGR & RCC_CFGR_SWS;
//  switch (tmp)
//  {
//    case 0x00:  /* HSI used as system clock source */
//      SystemCoreClock = HSI_VALUE;
//      break;
//    case 0x04:  /* HSE used as system clock source */
//      SystemCoreClock = HSE_VALUE;
//      break;
//    case 0x08:  /* PLL used as system clock source */
//
//      /* PLL_VCO = (HSE_VALUE or HSI_VALUE / PLL_M) * PLL_N
//         SYSCLK = PLL_VCO / PLL_P
//         */    
//      pllsource = (RCC->PLLCFGR & RCC_PLLCFGR_PLLSRC) >> 22;
//      pllm = RCC->PLLCFGR & RCC_PLLCFGR_PLLM;
//      
//      if (pllsource != 0)
//      {
//        /* HSE used as PLL clock source */
//        pllvco = (HSE_VALUE / pllm) * ((RCC->PLLCFGR & RCC_PLLCFGR_PLLN) >> 6);
//      }
//      else
//      {
//        /* HSI used as PLL clock source */
//        pllvco = (HSI_VALUE / pllm) * ((RCC->PLLCFGR & RCC_PLLCFGR_PLLN) >> 6);
//      }
//
//      pllp = (((RCC->PLLCFGR & RCC_PLLCFGR_PLLP) >>16) + 1 ) *2;
//      SystemCoreClock = pllvco/pllp;
//      break;
//    default:
//      SystemCoreClock = HSI_VALUE;
//      break;
//  }
//  /* Compute HCLK frequency --------------------------------------------------*/
//  /* Get HCLK prescaler */
//  tmp = AHBPrescTable[((RCC->CFGR & RCC_CFGR_HPRE) >> 4)];
//  /* HCLK frequency */
//  SystemCoreClock >>= tmp;
	SystemCoreClock = 180000000;
}

/**
  * @brief  Setup the external memory controller.
  *         Called in startup_stm32f4xx.s before jump to main.
  *         This function configures the external memories (SRAM/SDRAM)
  *         This SRAM/SDRAM will be used as program data memory (including heap and stack).
  * @param  None
  * @retval None
  */
void SystemInit_ExtMemCtl(void)
{
}
/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/