arch/arm/cpu/armv7m/mpu.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright (C) 2017, STMicroelectronics - All Rights Reserved
   4  * Author(s): Vikas Manocha, <vikas.manocha@st.com> for STMicroelectronics.
   5  */
   6
   7 #include <linux/bitops.h>
   8 #include <asm/armv7m.h>
   9 #include <asm/armv7_mpu.h>
  10 #include <asm/io.h>
  11
  12 #define V7M_MPU_CTRL_ENABLE             BIT(0)
  13 #define V7M_MPU_CTRL_DISABLE            (0 << 0)
  14 #define V7M_MPU_CTRL_HFNMIENA           BIT(1)
  15 #define V7M_MPU_CTRL_PRIVDEFENA         BIT(2)
  16 #define VALID_REGION                    BIT(4)
  17
  18 void disable_mpu(void)
  19 {
  20         writel(0, &V7M_MPU->ctrl);
  21 }
  22
  23 void enable_mpu(void)
  24 {
  25         writel(V7M_MPU_CTRL_ENABLE | V7M_MPU_CTRL_PRIVDEFENA, &V7M_MPU->ctrl);
  26
  27         /* Make sure new mpu config is effective for next memory access */
  28         dsb();
  29         isb();  /* Make sure instruction stream sees it */
  30 }
  31
  32 void mpu_config(struct mpu_region_config *reg_config)
  33 {
  34         uint32_t attr;
  35
  36         attr = get_attr_encoding(reg_config->mr_attr);
  37
  38         writel(reg_config->start_addr | VALID_REGION | reg_config->region_no,
  39                &V7M_MPU->rbar);
  40
  41         writel(reg_config->xn << XN_SHIFT | reg_config->ap << AP_SHIFT | attr
  42                 | reg_config->reg_size << REGION_SIZE_SHIFT | ENABLE_REGION
  43                , &V7M_MPU->rasr);
  44 }