u-boot/arch/arm/cpu/armv7m/mpu.c

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/*
* Copyright (C) 2017, STMicroelectronics - All Rights Reserved
* Author(s): Vikas Manocha, <vikas.manocha@st.com> for STMicroelectronics.
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <linux/bitops.h>
#include <asm/armv7m.h>
#include <asm/armv7m_mpu.h>
#include <asm/io.h>
#define V7M_MPU_CTRL_ENABLE (1 << 0)
#define V7M_MPU_CTRL_DISABLE (0 << 0)
#define V7M_MPU_CTRL_HFNMIENA (1 << 1)
#define VALID_REGION (1 << 4)
#define ENABLE_REGION (1 << 0)
#define AP_SHIFT 24
#define XN_SHIFT 28
#define TEX_SHIFT 19
#define S_SHIFT 18
#define C_SHIFT 17
#define B_SHIFT 16
#define REGION_SIZE_SHIFT 1
#define CACHEABLE (1 << C_SHIFT)
#define BUFFERABLE (1 << B_SHIFT)
#define SHAREABLE (1 << S_SHIFT)
void disable_mpu(void)
{
writel(0, &V7M_MPU->ctrl);
}
void enable_mpu(void)
{
writel(V7M_MPU_CTRL_ENABLE | V7M_MPU_CTRL_HFNMIENA, &V7M_MPU->ctrl);
/* Make sure new mpu config is effective for next memory access */
dsb();
isb(); /* Make sure instruction stream sees it */
}
void mpu_config(struct mpu_region_config *reg_config)
{
uint32_t attr;
switch (reg_config->mr_attr) {
case STRONG_ORDER:
attr = SHAREABLE;
break;
case SHARED_WRITE_BUFFERED:
attr = BUFFERABLE;
break;
case O_I_WT_NO_WR_ALLOC:
attr = CACHEABLE;
break;
case O_I_WB_NO_WR_ALLOC:
attr = CACHEABLE | BUFFERABLE;
break;
case O_I_NON_CACHEABLE:
attr = 1 << TEX_SHIFT;
break;
case O_I_WB_RD_WR_ALLOC:
attr = (1 << TEX_SHIFT) | CACHEABLE | BUFFERABLE;
break;
case DEVICE_NON_SHARED:
attr = (2 << TEX_SHIFT) | BUFFERABLE;
break;
default:
attr = 0; /* strongly ordered */
break;
};
writel(reg_config->start_addr | VALID_REGION | reg_config->region_no,
&V7M_MPU->rbar);
writel(reg_config->xn << XN_SHIFT | reg_config->ap << AP_SHIFT | attr
| reg_config->reg_size << REGION_SIZE_SHIFT | ENABLE_REGION
, &V7M_MPU->rasr);
}