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Hardware Information

Overview

The HW Info API provides access to hardware information such as device identifiers and reset cause flags.

Reset cause flags can be used to determine why the device was reset; for example due to a watchdog timeout or due to power cycling. Different devices support different subset of flags. Use hwinfo_get_supported_reset_cause() to retrieve the flags that are supported by that device.

Configuration Options

Related configuration options:

API Reference

group hwinfo_interface

Hardware Information Interface.

Reset cause flags

RESET_PIN

External pin.

RESET_SOFTWARE

Software reset.

RESET_BROWNOUT

Brownout (drop in voltage)

RESET_POR

Power-on reset (POR)

RESET_WATCHDOG

Watchdog timer expiration.

RESET_DEBUG

Debug event.

RESET_SECURITY

Security violation.

RESET_LOW_POWER_WAKE

Waking up from low power mode.

RESET_CPU_LOCKUP

CPU lock-up detected.

RESET_PARITY

Parity error.

RESET_PLL

PLL error.

RESET_CLOCK

Clock error.

RESET_HARDWARE

Hardware reset.

RESET_USER

User reset.

RESET_TEMPERATURE

Temperature reset.

Functions

ssize_t hwinfo_get_device_id(uint8_t *buffer, size_t length)

Copy the device id to a buffer.

This routine copies “length” number of bytes of the device ID to the buffer. If the device ID is smaller then length, the rest of the buffer is left unchanged. The ID depends on the hardware and is not guaranteed unique.

Drivers are responsible for ensuring that the ID data structure is a sequence of bytes. The returned ID value is not supposed to be interpreted based on vendor-specific assumptions of byte order. It should express the identifier as a raw byte sequence, doing any endian conversion necessary so that a hex representation of the bytes produces the intended serial number.

Parameters:
  • buffer – Buffer to write the ID to.

  • length – Max length of the buffer.

Return values:
  • size – of the device ID copied.

  • -ENOSYS – if there is no implementation for the particular device.

  • any – negative value on driver specific errors.

int hwinfo_get_reset_cause(uint32_t *cause)

Retrieve cause of device reset.

This routine retrieves the flags that indicate why the device was reset.

On some platforms the reset cause flags accumulate between successive resets and this routine may return multiple flags indicating all reset causes since the device was powered on. If you need to retrieve the cause only for the most recent reset call hwinfo_clear_reset_cause after calling this routine to clear the hardware flags before the next reset event.

Successive calls to this routine will return the same value, unless hwinfo_clear_reset_cause has been called.

Parameters:
Return values:
  • zero – if successful.

  • -ENOSYS – if there is no implementation for the particular device.

  • any – negative value on driver specific errors.

int hwinfo_clear_reset_cause(void)

Clear cause of device reset.

Clears reset cause flags.

Return values:
  • zero – if successful.

  • -ENOSYS – if there is no implementation for the particular device.

  • any – negative value on driver specific errors.

int hwinfo_get_supported_reset_cause(uint32_t *supported)

Get supported reset cause flags.

Retrieves all reset_cause flags that are supported by this device.

Parameters:
  • supported – OR’d reset cause flags that are supported

Return values:
  • zero – if successful.

  • -ENOSYS – if there is no implementation for the particular device.

  • any – negative value on driver specific errors.