critical_section

Critical Section API for short-lived mutual exclusion safe for IRQ and multi-core. More...

Data Structures
struct	critical_section
	Critical section instance. More...

Typedefs
typedef struct __packed_aligned critical_section	critical_section_t
	Critical section instance.

Functions
void	critical_section_init (critical_section_t *crit_sec)
	Initialise a critical_section structure allowing the system to assign a spin lock number.
void	critical_section_init_with_lock_num (critical_section_t *crit_sec, uint lock_num)
	Initialise a critical_section structure assigning a specific spin lock number.
static __force_inline void	critical_section_enter_blocking (critical_section_t *crit_sec)
	Enter a critical_section.
static __force_inline void	critical_section_exit (critical_section_t *crit_sec)
	Release a critical_section.
void	critical_section_deinit (critical_section_t *crit_sec)
	De-Initialise a critical_section created by the critical_section_init method.
static bool	critical_section_is_initialized (critical_section_t *crit_sec)
	Test whether a critical_section has been initialized.

Detailed Description

Critical Section API for short-lived mutual exclusion safe for IRQ and multi-core.

A critical section is non-reentrant, and provides mutual exclusion using a spin-lock to prevent access from the other core, and from (higher priority) interrupts on the same core. It does the former using a spin lock and the latter by disabling interrupts on the calling core.

Because interrupts are disabled when a critical_section is owned, uses of the critical_section should be as short as possible.

Typedef Documentation

critical_section_t

typedef struct __packed_aligned critical_section critical_section_t

Critical section instance.

Structure holding the state for a single critical section, including the associated spin lock and the saved interrupt state.

Function Documentation

critical_section_deinit()

void critical_section_deinit

(

critical_section_t *

crit_sec

)

De-Initialise a critical_section created by the critical_section_init method.

This method is only used to free the associated spin lock allocated via the critical_section_init method (it should not be used to de-initialize a spin lock created via critical_section_init_with_lock_num). After this call, the critical section is invalid

Parameters

crit_sec

Pointer to critical_section structure

critical_section_enter_blocking()

static __force_inline void critical_section_enter_blocking ( critical_section_t *  crit_sec )

static

Enter a critical_section.

If the spin lock associated with this critical section is in use, then this method will block until it is released.

Parameters

crit_sec

Pointer to critical_section structure

critical_section_exit()

static __force_inline void critical_section_exit ( critical_section_t *  crit_sec )

static

Release a critical_section.

Parameters

crit_sec

Pointer to critical_section structure

critical_section_init()

void critical_section_init

(

critical_section_t *

crit_sec

)

Initialise a critical_section structure allowing the system to assign a spin lock number.

The critical section is initialized ready for use, and will use a (possibly shared) spin lock number assigned by the system. Note that in general it is unlikely that you would be nesting critical sections, however if you do so you must use critical_section_init_with_lock_num to ensure that the spin locks used are different.

Parameters

crit_sec

Pointer to critical_section structure

critical_section_init_with_lock_num()

void critical_section_init_with_lock_num	(	critical_section_t *	crit_sec,
		uint	lock_num
	)

Initialise a critical_section structure assigning a specific spin lock number.

Parameters

crit_sec	Pointer to critical_section structure
lock_num	the specific spin lock number to use

critical_section_is_initialized()

static bool critical_section_is_initialized ( critical_section_t *  crit_sec )

inlinestatic

Test whether a critical_section has been initialized.

Parameters

crit_sec

Pointer to critical_section structure

Returns

true if the critical section is initialized, false otherwise