mpu.c

Go to the documentation of this file.

/*
 * Support and FAQ: visit <a href="https://www.microchip.com/support/">Microchip Support</a>
 */

#include "mpu.h"

/*----------------------------------------------------------------------------
 *        Exported functions

 *----------------------------------------------------------------------------*/
void mpu_enable(uint32_t dw_mpu_enable)
{
        MPU->CTRL = dw_mpu_enable ;
}

void mpu_set_region_num(uint32_t dw_region_num)
{
        MPU->RNR = dw_region_num;
}

void mpu_disable_region(void)
{
        MPU->RASR &= 0xfffffffe;
}

void mpu_set_region(uint32_t dw_region_base_addr, uint32_t dw_region_attr)
{
        MPU->RBAR = dw_region_base_addr;
        MPU->RASR = dw_region_attr;
}


uint32_t mpu_cal_mpu_region_size(uint32_t dw_actual_size_in_bytes)
{
        uint32_t dwRegionSize = 32;
        uint32_t dwReturnValue = 4;

        while( dwReturnValue < 31 ) {
                if( dw_actual_size_in_bytes <= dwRegionSize ) {
                        break;
                } else {
                        dwReturnValue++;
                }
                dwRegionSize <<= 1;
        }

        return ( dwReturnValue << 1 );
}


void mpu_update_regions(uint32_t dw_region_num, uint32_t dw_region_base_addr, uint32_t dw_region_attr)
{
    volatile irqflags_t flags;

        /* Get and clear the global interrupt flags */
        flags = cpu_irq_save();

        /* Clean up data and instruction buffer */
        __DSB();
        __ISB();

        /* Set active region */
        mpu_set_region_num(dw_region_num);

        /* Disable region */
        mpu_disable_region();

        /* Update region attribute */
        mpu_set_region( dw_region_base_addr, dw_region_attr);

        /* Clean up data and instruction buffer to make the new region taking
           effect at once */
        __DSB();
        __ISB();

        /* Restore global interrupt flags */
        cpu_irq_restore(flags);
}