crc.c File Reference

STM32G4 CRC public-layer implementation. More...

#include "common/phal_G4/crc/crc.h"
#include "common/phal_G4/crc/crc_priv.h"

Include dependency graph for crc.c:

Functions
void	PHAL_CRC_init (void)
	Initialize and configure the hardware CRC peripheral.
uint32_t	PHAL_CRC_calculate (const uint32_t *data, uint32_t words)
	Compute a CRC-32/MPEG-2 over a word buffer using the hardware unit.
static uint32_t	crc_step (uint32_t crc, uint32_t data)
	Fold one 32-bit word into the running CRC, four bits at a time, MSB-first.
uint32_t	PHAL_CRC_calculateSw (const uint32_t *data, uint32_t words)
	Software reference implementation of PHAL_CRC_calculate().

Variables
static const uint32_t	crc32_LUT [16]
	Lookup table for the CRC-32/MPEG-2 polynomial 0x04C11DB7.

Detailed Description

STM32G4 CRC public-layer implementation.

Author

Hannah Song (song8.nosp@m.92@p.nosp@m.urdue.nosp@m..edu)

Function Documentation

crc_step()

static uint32_t crc_step ( uint32_t crc, uint32_t data )

static

Fold one 32-bit word into the running CRC, four bits at a time, MSB-first.

Here is the caller graph for this function:

PHAL_CRC_calculate()

uint32_t PHAL_CRC_calculate	(	const uint32_t *	data,
		uint32_t	words )

Compute a CRC-32/MPEG-2 over a word buffer using the hardware unit.

Resets the CRC unit (reloading the initial value), feeds each 32-bit word into the peripheral in order, and returns the accumulated remainder. Input is consumed as 32-bit words fed most-significant-bit first; no reflection or final XOR is applied.

Assumes PHAL_CRC_init() has already been called. Uses the single shared CRC peripheral, so it is not reentrant and must not be called concurrently from another context.

Parameters

data	Pointer to the buffer of 32-bit words to process.
words	Number of 32-bit words in data.

Returns

The 32-bit CRC-32/MPEG-2 remainder over the input.

Here is the call graph for this function:

PHAL_CRC_calculateSw()

uint32_t PHAL_CRC_calculateSw	(	const uint32_t *	data,
		uint32_t	words )

Software reference implementation of PHAL_CRC_calculate().

Computes the same CRC-32/MPEG-2 remainder as PHAL_CRC_calculate() using a nibble lookup table, producing bit-identical results. Independent of the CRC peripheral: does not require PHAL_CRC_init() and touches no hardware registers. Intended as a cross-check against the hardware path, or as a fallback where the peripheral is unavailable.

Parameters

data	Pointer to the buffer of 32-bit words to process.
words	Number of 32-bit words in data.

Returns

The 32-bit CRC-32/MPEG-2 remainder over the input.

Here is the call graph for this function:

PHAL_CRC_init()

void PHAL_CRC_init

(

void

)

Initialize and configure the hardware CRC peripheral.

Enables the CRC peripheral clock on AHB1, then explicitly configures the unit for CRC-32/MPEG-2: 32-bit polynomial 0x04C11DB7, initial value 0xFFFFFFFF, no input or output bit reversal, and no final XOR. These parameters are written explicitly rather than relying on the peripheral's reset defaults.

Assumes the system and AHB clocks are already configured. Must be called once before any call to PHAL_CRC_calculate().

Here is the call graph for this function:

Variable Documentation

crc32_LUT

const uint32_t crc32_LUT[16]

static

Initial value:

= {
    0x00000000,
    0x04C11DB7,
    0x09823B6E,
    0x0D4326D9,
    0x130476DC,
    0x17C56B6B,
    0x1A864DB2,
    0x1E475005,
    0x2608EDB8,
    0x22C9F00F,
    0x2F8AD6D6,
    0x2B4BCB61,
    0x350C9B64,
    0x31CD86D3,
    0x3C8EA00A,
    0x384FBDBD,
}

Lookup table for the CRC-32/MPEG-2 polynomial 0x04C11DB7.