spmc.h File Reference

Custom SPMC designed for high throughput handling of CAN message streams. More...

#include <stddef.h>
#include <stdint.h>
#include <string.h>

Go to the source code of this file.

Classes
struct	timestamped_frame_t
struct	SPMC_t

Macros
#define	SPMC_BUS_ID_Pos   (31U)
#define	SPMC_IS_EXTID_Pos   (30U)

Enumerations
enum	SPMC_status_t : int { SPMC_OK = 0 , SPMC_FULL = -1 , SPMC_EMPTY = -2 }

Functions
void	SPMC_init (SPMC_t *spmc)
	Initializes the SPMC instance and configures CAN RX interrupts.
SPMC_status_t	SPMC_enqueue_from_ISR (SPMC_t *spmc, timestamped_frame_t *incoming_frame)
	Enqueues a received CAN message into the SPMC buffer from an ISR context. ! the two producer ISRs must have the same priority to prevent preemption in the middle of a write.
size_t	SPMC_master_peek_all (SPMC_t *spmc, timestamped_frame_t **first_item, size_t *total_unread)
	Peeks at the next batch of frames available for processing by the master (SD logging) without committing the tail. Intended to be used with a DMA operation.
void	SPMC_master_commit_tail (SPMC_t *spmc, size_t num_consumed)
	Commits the specified number of consumed frames by advancing the master tail pointer.
SPMC_status_t	SPMC_follower_pop (SPMC_t *spmc, timestamped_frame_t **out, uint32_t *consecutive_items)
	Pops a single frame for the follower (Ethernet transmission) and advances the follower tail pointer. todo: this function is incomplete todo: optimize for DMA batch transfers, similar to the master's function.

Detailed Description

Custom SPMC designed for high throughput handling of CAN message streams.

Author

Irving Wang (irvin.nosp@m.gw@p.nosp@m.urdue.nosp@m..edu)

Shriya Balu (balu@.nosp@m.purd.nosp@m.ue.ed.nosp@m.u)

Function Documentation

SPMC_enqueue_from_ISR()

SPMC_status_t SPMC_enqueue_from_ISR	(	SPMC_t *	spmc,
		timestamped_frame_t *	incoming_frame )

Enqueues a received CAN message into the SPMC buffer from an ISR context. ! the two producer ISRs must have the same priority to prevent preemption in the middle of a write.

Parameters

spmc	Pointer to the SPMC instance.
incoming_frame	Pointer to the timestamped_frame_t containing the received CAN message.

Returns

SPMC_OK if the frame was enqueued successfully, or SPMC_FULL if the buffer is full and the frame was dropped.

SPMC_follower_pop()

SPMC_status_t SPMC_follower_pop	(	SPMC_t *	spmc,
		timestamped_frame_t **	out,
		uint32_t *	consecutive_items )

Pops a single frame for the follower (Ethernet transmission) and advances the follower tail pointer. todo: this function is incomplete todo: optimize for DMA batch transfers, similar to the master's function.

Parameters

spmc	Pointer to the SPMC instance.
out	Output pointer to the popped frame.
consecutive_items	Output pointer to the number of consecutive frames available.

Returns

SPMC_OK if a frame was successfully popped, or SPMC_EMPTY if the buffer is empty.

SPMC_init()

void SPMC_init

(

SPMC_t *

spmc

)

Initializes the SPMC instance and configures CAN RX interrupts.

Parameters

spmc	Pointer to the SPMC instance to initialize.

SPMC_master_commit_tail()

void SPMC_master_commit_tail	(	SPMC_t *	spmc,
		size_t	num_consumed )

Commits the specified number of consumed frames by advancing the master tail pointer.

Parameters

spmc	Pointer to the SPMC instance.
num_consumed	The number of frames to commit.

SPMC_master_peek_all()

size_t SPMC_master_peek_all	(	SPMC_t *	spmc,
		timestamped_frame_t **	first_item,
		size_t *	total_unread )

Peeks at the next batch of frames available for processing by the master (SD logging) without committing the tail. Intended to be used with a DMA operation.

Parameters

spmc	Pointer to the SPMC instance.
first_item	Output pointer that will point to the first item in the batch if available, or NULL if no items are available.
total_unread	Output pointer that will be set to the total number of unread frames available in the buffer.

Returns

The number of contiguous items available in the batch.