trezor-firmware/embed/bootloader/mpu.c

#include STM32_HAL_H
#include "stm32f4xx_ll_cortex.h"

// http://infocenter.arm.com/help/topic/com.arm.doc.dui0552a/BABDJJGF.html
#define MPU_RASR_ATTR_FLASH  (MPU_RASR_C_Msk)
#define MPU_RASR_ATTR_SRAM   (MPU_RASR_C_Msk | MPU_RASR_S_Msk)
#define MPU_RASR_ATTR_PERIPH (MPU_RASR_B_Msk | MPU_RASR_S_Msk)

#define MPU_SUBREGION_DISABLE(X) ((X) << MPU_RASR_SRD_Pos)

void mpu_config(void)
{
    // Disable MPU
    HAL_MPU_Disable();

/*
    // Boardloader (0x08000000 - 0x0800FFFF, 64 KiB, read-only, execute never)
    MPU->RBAR = FLASH_BASE | MPU_RBAR_VALID_Msk | MPU_REGION_NUMBER0;
    MPU->RASR = MPU_RASR_ENABLE_Msk | MPU_RASR_ATTR_FLASH | LL_MPU_REGION_SIZE_64KB | LL_MPU_REGION_PRIV_RO_URO | MPU_RASR_XN_Msk;
*/

    // Bootloader (0x08020000 - 0x0803FFFF, 64 KiB, read-only)
    MPU->RBAR = FLASH_BASE | 0x20000 | MPU_RBAR_VALID_Msk | MPU_REGION_NUMBER0;
    MPU->RASR = MPU_RASR_ENABLE_Msk | MPU_RASR_ATTR_FLASH | LL_MPU_REGION_SIZE_64KB | LL_MPU_REGION_PRIV_RO_URO;

    // Storage#1 (0x08010000 - 0x0801FFFF, 64 KiB, read-write, execute never)
    MPU->RBAR = FLASH_BASE | 0x10000 | MPU_RBAR_VALID_Msk | MPU_REGION_NUMBER1;
    MPU->RASR = MPU_RASR_ENABLE_Msk | MPU_RASR_ATTR_FLASH | LL_MPU_REGION_SIZE_64KB | LL_MPU_REGION_FULL_ACCESS | MPU_RASR_XN_Msk;
    // Storage#2 (0x08110000 - 0x0811FFFF, 64 KiB, read-write, execute never)
    MPU->RBAR = FLASH_BASE | 0x110000 | MPU_RBAR_VALID_Msk | MPU_REGION_NUMBER2;
    MPU->RASR = MPU_RASR_ENABLE_Msk | MPU_RASR_ATTR_FLASH | LL_MPU_REGION_SIZE_64KB | LL_MPU_REGION_FULL_ACCESS | MPU_RASR_XN_Msk;

    // Firmware (0x08040000 - 0x080FFFFF, 6 * 128 KiB = 1024 KiB except 2/8 at start = 768 KiB, read-only)
    MPU->RBAR = FLASH_BASE | MPU_RBAR_VALID_Msk | MPU_REGION_NUMBER3;
    MPU->RASR = MPU_RASR_ENABLE_Msk | MPU_RASR_ATTR_FLASH | LL_MPU_REGION_SIZE_1MB | LL_MPU_REGION_PRIV_RO_URO | MPU_SUBREGION_DISABLE(0x03);

    // Firmware extra (0x08120000 - 0x081FFFFF, 7 * 128 KiB = 1024 KiB except 1/8 at start = 896 KiB, read-only)
    MPU->RBAR = FLASH_BASE | 0x100000 | MPU_RBAR_VALID_Msk | MPU_REGION_NUMBER4;
    MPU->RASR = MPU_RASR_ENABLE_Msk | MPU_RASR_ATTR_FLASH | LL_MPU_REGION_SIZE_1MB | LL_MPU_REGION_PRIV_RO_URO | MPU_SUBREGION_DISABLE(0x01);

    // CCMRAM (0x10000000 - 0x1000FFFF, read-write, execute never)
    MPU->RBAR = CCMDATARAM_BASE | MPU_RBAR_VALID_Msk | MPU_REGION_NUMBER5;
    MPU->RASR = MPU_RASR_ENABLE_Msk | MPU_RASR_ATTR_SRAM | LL_MPU_REGION_SIZE_64KB | LL_MPU_REGION_FULL_ACCESS | MPU_RASR_XN_Msk;

    // SRAM (0x20000000 - 0x2002FFFF, read-write, execute never)
    MPU->RBAR = SRAM_BASE | MPU_RBAR_VALID_Msk | MPU_REGION_NUMBER6;
    MPU->RASR = MPU_RASR_ENABLE_Msk | MPU_RASR_ATTR_SRAM | LL_MPU_REGION_SIZE_256KB | LL_MPU_REGION_FULL_ACCESS | MPU_RASR_XN_Msk | MPU_SUBREGION_DISABLE(0xC0);

    // Peripherals (0x40000000 - 0x5FFFFFFF, read-write, execute never)
    // External RAM (0x60000000 - 0x7FFFFFFF, read-write, execute never)
    MPU->RBAR = PERIPH_BASE | MPU_RBAR_VALID_Msk | MPU_REGION_NUMBER7;
    MPU->RASR = MPU_RASR_ENABLE_Msk | MPU_RASR_ATTR_PERIPH | LL_MPU_REGION_SIZE_1GB | LL_MPU_REGION_FULL_ACCESS | MPU_RASR_XN_Msk;

    // Enable MPU
    HAL_MPU_Enable(0);
}