mpu.h File Reference

Cortex-M Memory Protection Unit (MPU) Driver Header File. More...

Detailed Description

Cortex-M Memory Protection Unit (MPU) Driver Header File.

Author

Ian Martin ian@l.nosp@m.ocic.nosp@m.ontro.nosp@m.ls.c.nosp@m.om

Definition in file mpu.h.

#include <stdbool.h>
#include <stdint.h>

Include dependency graph for mpu.h:

Go to the source code of this file.

Macros
#define	MPU_NUM_REGIONS   ( (MPU->TYPE & MPU_TYPE_DREGION_Msk) >> MPU_TYPE_DREGION_Pos )
	Number of MPU regions available (will vary depending on the Cortex-M version)
#define	MPU_SIZE_TO_BYTES(size)   ( (uintptr_t)1 << ((size) + 1) )
	convert a region size code to a size in bytes

Enumerations
enum	{   AP_NO_NO = 0 , AP_RW_NO = 1 , AP_RW_RO = 2 , AP_RW_RW = 3 ,   AP_RO_NO = 5 , AP_RO_RO = 6 }
	Access Permission words. More...
enum	{   MPU_SIZE_32B = 4 , MPU_SIZE_64B = 5 , MPU_SIZE_128B = 6 , MPU_SIZE_256B = 7 ,   MPU_SIZE_512B = 8 , MPU_SIZE_1K = 9 , MPU_SIZE_2K = 10 , MPU_SIZE_4K = 11 ,   MPU_SIZE_8K = 12 , MPU_SIZE_16K = 13 , MPU_SIZE_32K = 14 , MPU_SIZE_64K = 15 ,   MPU_SIZE_128K = 16 , MPU_SIZE_256K = 17 , MPU_SIZE_512K = 18 , MPU_SIZE_1M = 19 ,   MPU_SIZE_2M = 20 , MPU_SIZE_4M = 21 , MPU_SIZE_8M = 22 , MPU_SIZE_16M = 23 ,   MPU_SIZE_32M = 24 , MPU_SIZE_64M = 25 , MPU_SIZE_128M = 26 , MPU_SIZE_256M = 27 ,   MPU_SIZE_512M = 28 , MPU_SIZE_1G = 29 , MPU_SIZE_2G = 30 , MPU_SIZE_4G = 31 }
	MPU region sizes. More...

Functions
static uint32_t	MPU_ATTR (uint32_t xn, uint32_t ap, uint32_t tex, uint32_t c, uint32_t b, uint32_t s, uint32_t size)
	generate an MPU attribute word suitable for writing to the RASR register
int	mpu_disable (void)
	disable the MPU
int	mpu_enable (void)
	enable the MPU
bool	mpu_enabled (void)
	test if the MPU is enabled
int	mpu_configure (uint_fast8_t region, uintptr_t base, uint_fast32_t attr)
	configure the base address and attributes for an MPU region

Macro Definition Documentation

MPU_NUM_REGIONS

#define MPU_NUM_REGIONS   ( (MPU->TYPE & MPU_TYPE_DREGION_Msk) >> MPU_TYPE_DREGION_Pos )

Number of MPU regions available (will vary depending on the Cortex-M version)

Definition at line 34 of file mpu.h.

MPU_SIZE_TO_BYTES

#define MPU_SIZE_TO_BYTES

(

size

)

( (uintptr_t)1 << ((size) + 1) )

convert a region size code to a size in bytes

Parameters

[in]

size

region size code, e.g. MPU_SIZE_32B

Returns

region size in bytes

Definition at line 89 of file mpu.h.

Enumeration Type Documentation

anonymous enum

anonymous enum

Access Permission words.

Enumerator
AP_NO_NO	no access for all levels
AP_RW_NO	read/write for privileged level, no access from user level
AP_RW_RO	read/write for privileged level, read-only for user level
AP_RW_RW	read/write for all levels
AP_RO_NO	read-only for privileged level, no access from user level
AP_RO_RO	read-only for all levels

Definition at line 39 of file mpu.h.

anonymous enum

anonymous enum

MPU region sizes.

Enumerator
MPU_SIZE_32B	32 bytes
MPU_SIZE_64B	64 bytes
MPU_SIZE_128B	128 bytes
MPU_SIZE_256B	256 bytes
MPU_SIZE_512B	512 bytes
MPU_SIZE_1K	1 kilobytes
MPU_SIZE_2K	2 kilobytes
MPU_SIZE_4K	4 kilobytes
MPU_SIZE_8K	8 kilobytes
MPU_SIZE_16K	16 kilobytes
MPU_SIZE_32K	32 kilobytes
MPU_SIZE_64K	64 kilobytes
MPU_SIZE_128K	128 kilobytes
MPU_SIZE_256K	256 kilobytes
MPU_SIZE_512K	512 kilobytes
MPU_SIZE_1M	1 megabytes
MPU_SIZE_2M	2 megabytes
MPU_SIZE_4M	4 megabytes
MPU_SIZE_8M	8 megabytes
MPU_SIZE_16M	16 megabytes
MPU_SIZE_32M	32 megabytes
MPU_SIZE_64M	64 megabytes
MPU_SIZE_128M	128 megabytes
MPU_SIZE_256M	256 megabytes
MPU_SIZE_512M	512 megabytes
MPU_SIZE_1G	1 gigabytes
MPU_SIZE_2G	2 gigabytes
MPU_SIZE_4G	4 gigabytes

Definition at line 51 of file mpu.h.

Function Documentation

MPU_ATTR()

static uint32_t MPU_ATTR ( uint32_t  xn, uint32_t  ap, uint32_t  tex, uint32_t  c, uint32_t  b, uint32_t  s, uint32_t  size  )

inlinestatic

generate an MPU attribute word suitable for writing to the RASR register

Parameters

[in]	xn	eXecute Never flag (forbids instruction fetches)
[in]	ap	Access Permission word, e.g. AP_RO_RO
[in]	tex	Type Extension Field
[in]	c	Cacheable bit
[in]	b	Bufferable bit
[in]	s	Sub-Region Disable (SRD) field
[in]	size	region size code, e.g. MPU_SIZE_32B

Returns

combined region attribute word

Definition at line 104 of file mpu.h.

mpu_configure()

int mpu_configure	(	uint_fast8_t	region,
		uintptr_t	base,
		uint_fast32_t	attr
	)

configure the base address and attributes for an MPU region

Parameters

[in]	region	MPU region to configure (0 <= region < MPU_NUM_REGIONS)
[in]	base	base address in RAM (aligned to the size specified within attr)
[in]	attr	attribute word generated by MPU_ATTR()

Returns

0 on success

<0 on failure or no MPU present

mpu_disable()

int mpu_disable

(

void

)

disable the MPU

Returns

0 on success

<0 on failure or no MPU present

mpu_enable()

int mpu_enable

(

void

)

enable the MPU

Returns

0 on success

<0 on failure or no MPU present

mpu_enabled()

bool mpu_enabled

(

void

)

test if the MPU is enabled

Returns

true if enabled

false if disabled