ARM Cortex-M common

Common implementations and headers for Cortex-M family based micro-controllers. More...

Detailed Description

Common implementations and headers for Cortex-M family based micro-controllers.

Files
file	architecture_arch.h
	Architecture details.
file	atomic_utils_arch.h
	Implementation of fast atomic utility functions.
file	cpu.h
	Basic definitions for the Cortex-M common module.
file	cpu_conf_common.h
	Common CPU definitione for Cortex-M family based MCUs.
file	irq_arch.h
	Implementation of the kernels irq interface.
file	mpu.h
	Cortex-M Memory Protection Unit (MPU) Driver Header File.
file	thread_arch.h
	Implementation of the kernels thread interface.
file	vectors_cortexm.h
	Default interrupt vectors shared by Cortex-M based CPUs.

Macros
#define	STACK_CANARY_WORD   (0xE7FEE7FEu)
	Interrupt stack canary value.
#define	PROVIDES_PM_SET_LOWEST
	All Cortex-m-based CPUs provide pm_set_lowest.
#define	CORTEXM_SCB_CPACR_FPU_ACCESS_FULL   (0x00f00000)
	Pattern to write into the co-processor Access Control Register to allow full FPU access.

Functions
void	cortexm_init (void)
	Initialize Cortex-M specific core parts of the CPU.
static void	cortexm_init_fpu (void)
	Initialize Cortex-M FPU.
void	cortexm_init_isr_priorities (void)
	Initialize Cortex-M interrupt priorities.
void	cortexm_init_misc (void)
	Initialize Cortex-M misc functions.
static uintptr_t	cpu_get_caller_pc (void)
	Returns the current content of the link register (lr)
static void	cortexm_sleep_until_event (void)
	Put the CPU into the 'wait for event' sleep mode.
static void	cortexm_sleep (int deep)
	Put the CPU into (deep) sleep mode, using the WFI instruction.
static void	cortexm_isr_end (void)
	Trigger a conditional context scheduler run / context switch.
static void	cpu_jump_to_image (uint32_t image_address)
	Jumps to another image in flash.
bool	cpu_check_address (volatile const char *address)
	Checks is memory address valid or not.

Macro Definition Documentation

CORTEXM_SCB_CPACR_FPU_ACCESS_FULL

#define CORTEXM_SCB_CPACR_FPU_ACCESS_FULL   (0x00f00000)

Pattern to write into the co-processor Access Control Register to allow full FPU access.

Used in the cortexm_init_fpu inline function below.

Definition at line 65 of file cpu.h.

PROVIDES_PM_SET_LOWEST

#define PROVIDES_PM_SET_LOWEST

All Cortex-m-based CPUs provide pm_set_lowest.

The pm_set_lowest is provided either by the pm_layered module if used, or alternatively as fallback by the cortexm's own implementation.

Definition at line 57 of file cpu.h.

STACK_CANARY_WORD

#define STACK_CANARY_WORD   (0xE7FEE7FEu)

Interrupt stack canary value.

Note

0xe7fe is the ARM Thumb machine code equivalent of asm("bl #-2\n") or 'while (1);', i.e. an infinite loop.

Definition at line 49 of file cpu.h.

Function Documentation

cortexm_init()

void cortexm_init

(

void

)

Initialize Cortex-M specific core parts of the CPU.

cortexm_init calls, in a default order, cortexm_init_fpu, cortexm_init_isr_priorities, and cortexm_init_misc. Also performs other default initialisations, including ones which you may or may not want.

Unless you have special requirements (like nRF52 with SD has), it is sufficient to call just cortexm_init and the cortexm_init_* functions do not need to (and should not) be called separately. If you have conflicting requirements, you may want to have a look cpu/nrft/cpu.c for an example of a non-default approach.

cortexm_init_fpu()

static void cortexm_init_fpu ( void  )

inlinestatic

Initialize Cortex-M FPU.

Called from cpu/nrf52/cpu.c, since it cannot use the whole cortexm_init due to conflicting requirements.

Defined here as a static inline function to allow all callers to optimise this away if the FPU is not used.

Definition at line 92 of file cpu.h.

cortexm_init_isr_priorities()

void cortexm_init_isr_priorities

(

void

)

Initialize Cortex-M interrupt priorities.

Called from cpu/nrf52/cpu.c, since it cannot use the whole cortexm_init due to conflicting requirements.

Define CPU_CORTEXM_INIT_SUBFUNCTIONS to make this function publicly available.

cortexm_init_misc()

void cortexm_init_misc

(

void

)

Initialize Cortex-M misc functions.

Called from cpu/nrf52/cpu.c, since it cannot use the whole cortexm_init due to conflicting requirements.

Define CPU_CORTEXM_INIT_SUBFUNCTIONS to make this function publicly available.

cortexm_isr_end()

static void cortexm_isr_end ( void  )

inlinestatic

Trigger a conditional context scheduler run / context switch.

This function is supposed to be called in the end of each ISR.

Definition at line 180 of file cpu.h.

cortexm_sleep()

static void cortexm_sleep ( int  deep )

inlinestatic

Put the CPU into (deep) sleep mode, using the WFI instruction.

Parameters

[in]

deep

!=0 for deep sleep, 0 for light sleep

Definition at line 155 of file cpu.h.

cortexm_sleep_until_event()

static void cortexm_sleep_until_event ( void  )

inlinestatic

Put the CPU into the 'wait for event' sleep mode.

This function is meant to be used for short periods of time, where it is not feasible to switch to the idle thread and back.

Definition at line 145 of file cpu.h.

cpu_check_address()

bool cpu_check_address

(

volatile const char *

address

)

Checks is memory address valid or not.

This function can be used to check for memory size, peripherals availability, etc.

Parameters

[in]

address

Address to check

Returns

true if address is valid

cpu_get_caller_pc()

static uintptr_t cpu_get_caller_pc ( void  )

inlinestatic

Returns the current content of the link register (lr)

Returns

content of the link register (lr)

Definition at line 132 of file cpu.h.

cpu_jump_to_image()

static void cpu_jump_to_image ( uint32_t  image_address )

inlinestatic

Jumps to another image in flash.

This function is supposed to be called by a bootloader application.

Parameters

[in]

image_address

address in flash of other image

Definition at line 194 of file cpu.h.