lastwords.h File Reference

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

Data Structures
struct	kfsw_lastwords

Enumerations
enum	kfsw_lastwords_reason {   KFSW_LASTWORDS_NONE = 0 , KFSW_LASTWORDS_COMMANDED = 1 , KFSW_LASTWORDS_BROWNOUT = 2 , KFSW_LASTWORDS_FATAL = 3 ,   KFSW_LASTWORDS_STARVED = 4 , KFSW_LASTWORDS_UNKNOWN = 5 }

Functions
void	kfsw_lastwords_write (enum kfsw_lastwords_reason reason, uint32_t detail, uint32_t uptime_ms, uint32_t boot_count)
bool	kfsw_lastwords_take (struct kfsw_lastwords *record)
bool	kfsw_lastwords_withdraw (enum kfsw_lastwords_reason reason)
const char *	kfsw_lastwords_reason_name (enum kfsw_lastwords_reason reason)
int	kfsw_lastwords_watch_supply (void)

Description

A note written before a restart, kept in RAM that start-up does not clear.

It survives a reset but not a power loss, and a magic number and a CRC validate it.

Enumeration Documentation

kfsw_lastwords_reason

enum kfsw_lastwords_reason

Reset reason.

Enumerator
KFSW_LASTWORDS_NONE	No valid reset note.
KFSW_LASTWORDS_COMMANDED	An operator or the ground asked for a restart.
KFSW_LASTWORDS_BROWNOUT	The supply fell far enough for the detector to fire.
KFSW_LASTWORDS_FATAL	A fatal error handler ran.
KFSW_LASTWORDS_STARVED	Health stopped feeding the watchdog.
KFSW_LASTWORDS_UNKNOWN	Restart without a more specific reason.

Function Documentation

kfsw_lastwords_reason_name()

const char * kfsw_lastwords_reason_name

(

enum kfsw_lastwords_reason

reason

)

Human-readable name for a reason, for the shell and the log.

kfsw_lastwords_take()

bool kfsw_lastwords_take

(

struct kfsw_lastwords *

record

)

Read the note and clear it.

Returns true when a valid note was found. Returns false without clearing the note if another operation owns it.

kfsw_lastwords_watch_supply()

int kfsw_lastwords_watch_supply

(

void

)

Start the supply voltage detector.

Returns 0 when a detector is armed, or -ENOTSUP when the SoC has none.

kfsw_lastwords_withdraw()

bool kfsw_lastwords_withdraw

(

enum kfsw_lastwords_reason

reason

)

Clear the note if its reason matches.

Returns true when it was cleared. Returns false if another operation owns the record.

kfsw_lastwords_write()

void kfsw_lastwords_write	(	enum kfsw_lastwords_reason	reason,
		uint32_t	detail,
		uint32_t	uptime_ms,
		uint32_t	boot_count
	)

Write a note without waiting, including from an interrupt.

A concurrent or nested operation is ignored while another owns the record. Sequential writes replace the previous note; there is no severity arbitration.