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/* Copyright 2013 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
/* MPU module for Cortex-M3 */
#ifndef __CROS_EC_MPU_H
#define __CROS_EC_MPU_H
#include "common.h"
#include "config.h" /* chips might override MPU attribute settings */
/*
* ARMv7-M SRAM region
*/
#define CORTEX_M_SRAM_BASE 0x20000000
/*
* Region assignment. 7 as the highest, a higher index has a higher priority.
* For example, using 7 for .iram.text allows us to mark entire RAM XN except
* .iram.text, which is used for hibernation.
* Region assignment is currently wasteful and can be changed if more
* regions are needed in the future. For example, a second region may not
* be necessary for all types, and REGION_CODE_RAM / REGION_STORAGE can be
* made mutually exclusive.
*/
enum mpu_region {
REGION_DATA_RAM = 0, /* For internal data RAM */
REGION_DATA_RAM2 = 1, /* Second region for unaligned size */
REGION_CODE_RAM = 2, /* For internal code RAM */
REGION_CODE_RAM2 = 3, /* Second region for unaligned size */
REGION_STORAGE = 4, /* For mapped internal storage */
REGION_STORAGE2 = 5, /* Second region for unaligned size */
REGION_DATA_RAM_TEXT = 6, /* Exempt region of data RAM */
REGION_CHIP_RESERVED = 7, /* Reserved for use in chip/ */
/* only for chips with MPU supporting 16 regions */
REGION_UNCACHED_RAM = 8, /* For uncached data RAM */
REGION_UNCACHED_RAM2 = 9, /* Second region for unaligned size */
REGION_ROLLBACK = 10, /* For rollback */
};
#define MPU_TYPE REG32(0xe000ed90)
#define MPU_CTRL REG32(0xe000ed94)
#define MPU_NUMBER REG32(0xe000ed98)
#define MPU_BASE REG32(0xe000ed9c)
#define MPU_SIZE REG16(0xe000eda0)
#define MPU_ATTR REG16(0xe000eda2)
/*
* See ARM v7-M Architecture Reference Manual
* Section B3.5.5 MPU Type Register, MPU_TYPE
*/
#define MPU_TYPE_UNIFIED_MASK 0x00FF0001
#define MPU_TYPE_REG_COUNT(t) (((t) >> 8) & 0xFF)
#define MPU_CTRL_PRIVDEFEN BIT(2)
#define MPU_CTRL_HFNMIENA BIT(1)
#define MPU_CTRL_ENABLE BIT(0)
/*
* Minimum region size is 32 bytes, 5 bits of address space
*/
#define MPU_SIZE_BITS_MIN 5
/*
* XN (execute never) bit. It's bit 12 if accessed by halfword.
* 0: XN off
* 1: XN on
*/
#define MPU_ATTR_XN BIT(12)
/* AP bit. See table 3-5 of Stellaris LM4F232H5QC datasheet for details */
#define MPU_ATTR_NO_NO (0 << 8) /* previleged no access, unprev no access */
#define MPU_ATTR_RW_NO (1 << 8) /* previleged ReadWrite, unprev no access */
#define MPU_ATTR_RW_RO (2 << 8) /* previleged ReadWrite, unprev Read-only */
#define MPU_ATTR_RW_RW (3 << 8) /* previleged ReadWrite, unprev ReadWrite */
#define MPU_ATTR_RO_NO (5 << 8) /* previleged Read-only, unprev no access */
/* Suggested value for TEX S/C/B bit. See table 3-6 of Stellaris LM4F232H5QC
* datasheet and table 38 of STM32F10xxx Cortex-M3 programming manual. */
#ifndef MPU_ATTR_INTERNAL_SRAM
#define MPU_ATTR_INTERNAL_SRAM 6 /* for Internal SRAM */
#endif
#ifndef MPU_ATTR_FLASH_MEMORY
#define MPU_ATTR_FLASH_MEMORY 2 /* for flash memory */
#endif
/* Represent RW with at most 2 MPU regions. */
#define MAX_RW_REGIONS 2
struct mpu_rw_regions {
int num_regions;
uint32_t addr[MAX_RW_REGIONS];
uint32_t size[MAX_RW_REGIONS];
};
/**
* Enable MPU
*/
void mpu_enable(void);
/**
* Returns the value of MPU type register
*
* Bit fields:
* [15:8] Number of the data regions implemented or 0 if MPU is not present.
* [1] 0: unified (no distinction between instruction and data)
* 1: separated
*/
uint32_t mpu_get_type(void);
/* Location of iram.text */
extern char __iram_text_start;
extern char __iram_text_end;
/**
* Protect RAM from code execution
*/
int mpu_protect_data_ram(void);
/**
* Protect code RAM from being overwritten
*/
int mpu_protect_code_ram(void);
/**
* Protect internal mapped flash memory from code execution
*/
int mpu_lock_ro_flash(void);
int mpu_lock_rw_flash(void);
/**
* Protect/unprotect rollback region readback.
*/
int mpu_lock_rollback(int lock);
/**
* Initialize MPU.
* It disables all regions if MPU is implemented. Otherwise, returns
* EC_ERROR_UNIMPLEMENTED.
*/
int mpu_pre_init(void);
#endif /* __CROS_EC_MPU_H */
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