examples/platform/openiotsdk/tf-m/targets/an552/device/source/system_core_init.c

/*
 * Copyright (c) 2009-2022 Arm Limited. All rights reserved.
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * 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
 *
 * 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.
 */

/*
 * This file is derivative of CMSIS V5.9.0 system_ARMCM55.c
 * Git SHA: 2b7495b8535bdcb306dac29b9ded4cfb679d7e5c
 */

#include "cmsis.h"

/*----------------------------------------------------------------------------
  Define clocks
 *----------------------------------------------------------------------------*/
#define XTAL (32000000UL)
#define SYSTEM_CLOCK (XTAL)
#define PERIPHERAL_CLOCK (25000000UL)

/*----------------------------------------------------------------------------
  Exception / Interrupt Vector table
 *----------------------------------------------------------------------------*/
extern const VECTOR_TABLE_Type __VECTOR_TABLE[496];

/*----------------------------------------------------------------------------
  System Core Clock Variable
 *----------------------------------------------------------------------------*/
uint32_t SystemCoreClock = SYSTEM_CLOCK;
uint32_t PeripheralClock = PERIPHERAL_CLOCK;

/*----------------------------------------------------------------------------
  System Core Clock update function
 *----------------------------------------------------------------------------*/
void SystemCoreClockUpdate(void)
{
    SystemCoreClock = SYSTEM_CLOCK;
    PeripheralClock = PERIPHERAL_CLOCK;
}

/*----------------------------------------------------------------------------
  System initialization function
 *----------------------------------------------------------------------------*/
void SystemInit(void)
{
#if defined(__VTOR_PRESENT) && (__VTOR_PRESENT == 1U)
    SCB->VTOR = (uint32_t)(&__VECTOR_TABLE[0]);
#endif

#if (defined(__FPU_USED) && (__FPU_USED == 1U)) || (defined(__ARM_FEATURE_MVE) && (__ARM_FEATURE_MVE > 0U))
    SCB->CPACR |= ((3U << 10U * 2U) | /* enable CP10 Full Access */
                   (3U << 11U * 2U)); /* enable CP11 Full Access */

    /* Set low-power state for PDEPU                */
    /*  0b00  | ON, PDEPU is not in low-power state */
    /*  0b01  | ON, but the clock is off            */
    /*  0b10  | RET(ention)                         */
    /*  0b11  | OFF                                 */

    /* Clear ELPSTATE, value is 0b11 on Cold reset */
    PWRMODCTL->CPDLPSTATE &= ~(PWRMODCTL_CPDLPSTATE_ELPSTATE_Msk);

    /* Favor best FP/MVE performance by default, avoid EPU switch-ON delays */
    /* PDEPU ON, Clock OFF */
    PWRMODCTL->CPDLPSTATE |= 0x1 << PWRMODCTL_CPDLPSTATE_ELPSTATE_Pos;
#endif

#ifdef UNALIGNED_SUPPORT_DISABLE
    SCB->CCR |= SCB_CCR_UNALIGN_TRP_Msk;
#endif

    /* Enable Loop and branch info cache */
    SCB->CCR |= SCB_CCR_LOB_Msk;
    __DSB();
    __ISB();

    SystemCoreClock = SYSTEM_CLOCK;
    PeripheralClock = PERIPHERAL_CLOCK;
}