Event Source

Kernel-space event source declarations.

Event sources are used to wake up user-space tasks when a specific event (such as a hardware interrupt from a specific peripheral device) occurs.

This part of the API is only applicable to kernel-space code.

Note that the comments in this file regarding Linux UIO and Xenomai UDD implementations are based on linux-cip-4.19.94-cip18 and xenomai-3.1, but other versions are probably very similar.

enum cuddlk_eventsrc_flags: Event source flags for kernel space.

Constants

CUDDLK_EVENTSRCF_SHARED: Indicates that the associated event source may be claimed by more than one user-space application simultaneously.

Description

Flags that describe the properties of an event source. These may be used in the flags member of the cuddlk_eventsrc struct.

struct cuddlk_eventsrc_kernel: Kernel-managed event source data members.

Definition

struct cuddlk_eventsrc_kernel {
  int ref_count;
};

Members

ref_count: Number of user-space applications that have claimed this event source. This should be either 0 or 1 unless the event source has the CUDDLK_EVENTSRCF_SHARED flag set.

Description

Kernel-managed cuddlk_eventsrc data members that are available for use by Cuddl drivers.

struct cuddlk_eventsrc: Event source information (kernel-space).

Definition

struct cuddlk_eventsrc {
  char *name;
  int flags;
  struct cuddlk_interrupt intr;
  struct cuddlk_eventsrc_kernel kernel;
  struct cuddlki_eventsrc_priv priv;
};

Members

name: Name used to identify the event source.
flags: Flags that describe the properties of the event source. This field may be a set of cuddlk_eventsrc_flags ORed together.
intr: Data structure for managing the interrupt handler and enable/disable functions.
kernel: Kernel-managed memory region data that is available for use by Cuddl drivers.
priv: Private memory region data reserved for internal use by the Cuddl implementation.

Description

Represents an event source (usually triggered by an interrupt) that may be monitored by user-space applications.

Unused members of this data structure must be set to zero. This is typically done by allocating this structure via kzalloc() or using memset() to zeroize the structure after allocation.

void cuddlk_eventsrc_notify(struct cuddlk_eventsrc *eventsrc): Programmatically trigger a user-space event.

Parameters

struct cuddlk_eventsrc *eventsrc: Event source to notify.

Description

Trigger a user-space interrupt event for the specified device. This routine is typically not called directly unless the event source’s intr.irq field is set to CUDDLK_IRQ_CUSTOM. If the event source is directly associated with a hardware interrupt (i.e. int.irq > 0), then user-space events are triggered automatically without calling this function.

Linux UIO equivalent in linux/uio_driver.h:

void uio_event_notify(struct uio_info *info);

Xenomai UDD equivalent in rtdm/udd.h:

void udd_notify_event(struct udd_device *udd)