From ef92c9ee2cf4745637635ec1895399e4f013914c Mon Sep 17 00:00:00 2001 From: Stefan Kerkmann Date: Fri, 18 Jun 2021 01:09:43 +0200 Subject: Add CRC8 calculation subsystem to quantum (#12641) * Intended usage is data validation in split transport code. * Default space efficient algorithm. * Opt-in fast table based algorithmn with #define CRC8_USE_TABLE switch. * Define switches for size and speed optimized versions, the default is size optimized by using uint_least8_t as datatype for calculations. * #define CRC8_OPTIMIZE_SPEED uses uint_fast8_t as datatype for calculations, this only affects 32-bit Archs like ARM and RISC-V. * Placeholder crc_init() function for hardware backed crc calculation, not implemented yet. --- quantum/crc.h | 44 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+) create mode 100644 quantum/crc.h (limited to 'quantum/crc.h') diff --git a/quantum/crc.h b/quantum/crc.h new file mode 100644 index 0000000000..c17f5888e2 --- /dev/null +++ b/quantum/crc.h @@ -0,0 +1,44 @@ +/* Copyright 2021 QMK + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + */ + +#pragma once + +#include "quantum.h" + +/** + * The type of the CRC values. + * + * This type must be big enough to contain at least 8 bits. + */ +#if defined(CRC8_OPTIMIZE_SPEED) +typedef uint_fast8_t crc_t; +#else +typedef uint_least8_t crc_t; +#endif + +/** + * Initialize crc subsystem. + */ +__attribute__((weak)) void crc_init(void); + +/** + * Generate CRC8 value from given data. + * + * \param[in] data Pointer to a buffer of \a data_len bytes. + * \param[in] data_len Number of bytes in the \a data buffer. + * \return The calculated crc value. + */ +__attribute__((weak)) uint8_t crc8(const void *data, size_t data_len); \ No newline at end of file -- cgit v1.2.1