RTC auf true
Diff: drivers/MbedCRC.h
- Revision:
- 0:38ceb79fef03
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/drivers/MbedCRC.h Wed Nov 28 15:10:15 2018 +0000 @@ -0,0 +1,562 @@ +/* mbed Microcontroller Library + * Copyright (c) 2018 ARM Limited + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +#ifndef MBED_CRC_API_H +#define MBED_CRC_API_H + +#include "drivers/TableCRC.h" +#include "hal/crc_api.h" +#include "platform/mbed_assert.h" +#include "platform/SingletonPtr.h" +#include "platform/PlatformMutex.h" + +/* This is invalid warning from the compiler for below section of code +if ((width < 8) && (NULL == _crc_table)) { + p_crc = (uint32_t)(p_crc << (8 - width)); +} +Compiler warns of the shift operation with width as it is width=(std::uint8_t), +but we check for ( width < 8) before performing shift, so it should not be an issue. +*/ +#if defined ( __CC_ARM ) +#pragma diag_suppress 62 // Shift count is negative +#elif defined ( __GNUC__ ) +#pragma GCC diagnostic push +#pragma GCC diagnostic ignored "-Wshift-count-negative" +#elif defined (__ICCARM__) +#pragma diag_suppress=Pe062 // Shift count is negative +#endif + +namespace mbed { +/** \addtogroup drivers */ +/** @{*/ + +/** CRC object provides CRC generation through hardware/software + * + * ROM polynomial tables for supported polynomials (:: crc_polynomial_t) will be used for + * software CRC computation, if ROM tables are not available then CRC is computed runtime + * bit by bit for all data input. + * @note Synchronization level: Thread safe + * + * @tparam polynomial CRC polynomial value in hex + * @tparam width CRC polynomial width + * + * Example: Compute CRC data + * @code + * + * #include "mbed.h" + * + * int main() { + * MbedCRC<POLY_32BIT_ANSI, 32> ct; + * + * char test[] = "123456789"; + * uint32_t crc = 0; + * + * printf("\nPolynomial = 0x%lx Width = %d \n", ct.get_polynomial(), ct.get_width()); + * + * ct.compute((void *)test, strlen((const char*)test), &crc); + * + * printf("The CRC of data \"123456789\" is : 0x%lx\n", crc); + * return 0; + * } + * @endcode + * Example: Compute CRC with data available in parts + * @code + * + * #include "mbed.h" + * int main() { + * MbedCRC<POLY_32BIT_ANSI, 32> ct; + * + * char test[] = "123456789"; + * uint32_t crc = 0; + * + * printf("\nPolynomial = 0x%lx Width = %d \n", ct.get_polynomial(), ct.get_width()); + * ct.compute_partial_start(&crc); + * ct.compute_partial((void *)&test, 4, &crc); + * ct.compute_partial((void *)&test[4], 5, &crc); + * ct.compute_partial_stop(&crc); + * printf("The CRC of data \"123456789\" is : 0x%lx\n", crc); + * return 0; + * } + * @endcode + * @ingroup drivers + */ + +extern SingletonPtr<PlatformMutex> mbed_crc_mutex; + +template <uint32_t polynomial = POLY_32BIT_ANSI, uint8_t width = 32> +class MbedCRC { + +public: + enum CrcMode + { +#ifdef DEVICE_CRC + HARDWARE = 0, +#endif + TABLE = 1, + BITWISE + }; + + typedef uint64_t crc_data_size_t; + + /** Lifetime of CRC object + * + * @param initial_xor Inital value/seed to Xor + * @param final_xor Final Xor value + * @param reflect_data + * @param reflect_remainder + * @note Default constructor without any arguments is valid only for supported CRC polynomials. :: crc_polynomial_t + * MbedCRC <POLY_7BIT_SD, 7> ct; --- Valid POLY_7BIT_SD + * MbedCRC <0x1021, 16> ct; --- Valid POLY_16BIT_CCITT + * MbedCRC <POLY_16BIT_CCITT, 32> ct; --- Invalid, compilation error + * MbedCRC <POLY_16BIT_CCITT, 32> ct (i,f,rd,rr) Constructor can be used for not supported polynomials + * MbedCRC<POLY_16BIT_CCITT, 16> sd(0, 0, false, false); Constructor can also be used for supported + * polynomials with different intial/final/reflect values + * + */ + MbedCRC(uint32_t initial_xor, uint32_t final_xor, bool reflect_data, bool reflect_remainder) : + _initial_value(initial_xor), _final_xor(final_xor), _reflect_data(reflect_data), + _reflect_remainder(reflect_remainder) + { + mbed_crc_ctor(); + } + MbedCRC(); + virtual ~MbedCRC() + { + // Do nothing + } + + /** Compute CRC for the data input + * Compute CRC performs the initialization, computation and collection of + * final CRC. + * + * @param buffer Data bytes + * @param size Size of data + * @param crc CRC is the output value + * @return 0 on success, negative error code on failure + */ + int32_t compute(void *buffer, crc_data_size_t size, uint32_t *crc) + { + MBED_ASSERT(crc != NULL); + int32_t status = 0; + + status = compute_partial_start(crc); + if (0 != status) { + unlock(); + return status; + } + + status = compute_partial(buffer, size, crc); + if (0 != status) { + unlock(); + return status; + } + + status = compute_partial_stop(crc); + if (0 != status) { + *crc = 0; + } + + return status; + + } + + /** Compute partial CRC for the data input. + * + * CRC data if not available fully, CRC can be computed in parts with available data. + * + * In case of hardware, intermediate values and states are saved by hardware. Mutex + * locking is used to serialize access to hardware CRC. + * + * In case of software CRC, previous CRC output should be passed as argument to the + * current compute_partial call. Please note the intermediate CRC value is maintained by + * application and not the driver. + * + * @pre: Call `compute_partial_start` to start the partial CRC calculation. + * @post: Call `compute_partial_stop` to get the final CRC value. + * + * @param buffer Data bytes + * @param size Size of data + * @param crc CRC value is intermediate CRC value filled by API. + * @return 0 on success or a negative error code on failure + * @note: CRC as output in compute_partial is not final CRC value, call `compute_partial_stop` + * to get final correct CRC value. + */ + int32_t compute_partial(void *buffer, crc_data_size_t size, uint32_t *crc) + { + int32_t status = 0; + + switch (_mode) { +#ifdef DEVICE_CRC + case HARDWARE: + hal_crc_compute_partial((uint8_t *)buffer, size); + *crc = 0; + break; +#endif + case TABLE: + status = table_compute_partial(buffer, size, crc); + break; + case BITWISE: + status = bitwise_compute_partial(buffer, size, crc); + break; + default: + status = -1; + break; + } + + return status; + } + + /** Compute partial start, indicate start of partial computation. + * + * This API should be called before performing any partial computation + * with compute_partial API. + * + * @param crc Initial CRC value set by the API + * @return 0 on success or a negative in case of failure + * @note: CRC is an out parameter and must be reused with compute_partial + * and `compute_partial_stop` without any modifications in application. + */ + int32_t compute_partial_start(uint32_t *crc) + { + MBED_ASSERT(crc != NULL); + +#ifdef DEVICE_CRC + if (_mode == HARDWARE) { + lock(); + crc_mbed_config_t config; + config.polynomial = polynomial; + config.width = width; + config.initial_xor = _initial_value; + config.final_xor = _final_xor; + config.reflect_in = _reflect_data; + config.reflect_out = _reflect_remainder; + + hal_crc_compute_partial_start(&config); + } +#endif + + *crc = _initial_value; + return 0; + } + + /** Get the final CRC value of partial computation. + * + * CRC value available in partial computation is not correct CRC, as some + * algorithms require remainder to be reflected and final value to be XORed + * This API is used to perform final computation to get correct CRC value. + * + * @param crc CRC result + * @return 0 on success or a negative in case of failure. + */ + int32_t compute_partial_stop(uint32_t *crc) + { + MBED_ASSERT(crc != NULL); + +#ifdef DEVICE_CRC + if (_mode == HARDWARE) { + *crc = hal_crc_get_result(); + unlock(); + return 0; + } +#endif + uint32_t p_crc = *crc; + if ((width < 8) && (NULL == _crc_table)) { + p_crc = (uint32_t)(p_crc << (8 - width)); + } + // Optimized algorithm for 32BitANSI does not need additional reflect_remainder + if ((TABLE == _mode) && (POLY_32BIT_REV_ANSI == polynomial)) { + *crc = (p_crc ^ _final_xor) & get_crc_mask(); + } else { + *crc = (reflect_remainder(p_crc) ^ _final_xor) & get_crc_mask(); + } + unlock(); + return 0; + } + + /** Get the current CRC polynomial. + * + * @return Polynomial value + */ + uint32_t get_polynomial(void) const + { + return polynomial; + } + + /** Get the current CRC width + * + * @return CRC width + */ + uint8_t get_width(void) const + { + return width; + } + +private: + uint32_t _initial_value; + uint32_t _final_xor; + bool _reflect_data; + bool _reflect_remainder; + uint32_t *_crc_table; + CrcMode _mode; + + /** Acquire exclusive access to CRC hardware/software. + */ + void lock() + { +#ifdef DEVICE_CRC + if (_mode == HARDWARE) { + mbed_crc_mutex->lock(); + } +#endif + } + + /** Release exclusive access to CRC hardware/software. + */ + virtual void unlock() + { +#ifdef DEVICE_CRC + if (_mode == HARDWARE) { + mbed_crc_mutex->unlock(); + } +#endif + } + + /** Get the current CRC data size. + * + * @return CRC data size in bytes + */ + uint8_t get_data_size(void) const + { + return (width <= 8 ? 1 : (width <= 16 ? 2 : 4)); + } + + /** Get the top bit of current CRC. + * + * @return Top bit is set high for respective data width of current CRC + * Top bit for CRC width less then 8 bits will be set as 8th bit. + */ + uint32_t get_top_bit(void) const + { + return (width < 8 ? (1u << 7) : (uint32_t)(1ul << (width - 1))); + } + + /** Get the CRC data mask. + * + * @return CRC data mask is generated based on current CRC width + */ + uint32_t get_crc_mask(void) const + { + return (width < 8 ? ((1u << 8) - 1) : (uint32_t)((uint64_t)(1ull << width) - 1)); + } + + /** Final value of CRC is reflected. + * + * @param data final crc value, which should be reflected + * @return Reflected CRC value + */ + uint32_t reflect_remainder(uint32_t data) const + { + if (_reflect_remainder) { + uint32_t reflection = 0x0; + uint8_t const nBits = (width < 8 ? 8 : width); + + for (uint8_t bit = 0; bit < nBits; ++bit) { + if (data & 0x01) { + reflection |= (1 << ((nBits - 1) - bit)); + } + data = (data >> 1); + } + return (reflection); + } else { + return data; + } + } + + /** Data bytes are reflected. + * + * @param data value to be reflected + * @return Reflected data value + */ + uint32_t reflect_bytes(uint32_t data) const + { + if (_reflect_data) { + uint32_t reflection = 0x0; + + for (uint8_t bit = 0; bit < 8; ++bit) { + if (data & 0x01) { + reflection |= (1 << (7 - bit)); + } + data = (data >> 1); + } + return (reflection); + } else { + return data; + } + } + + /** Bitwise CRC computation. + * + * @param buffer data buffer + * @param size size of the data + * @param crc CRC value is filled in, but the value is not the final + * @return 0 on success or a negative error code on failure + */ + int32_t bitwise_compute_partial(const void *buffer, crc_data_size_t size, uint32_t *crc) const + { + MBED_ASSERT(crc != NULL); + + const uint8_t *data = static_cast<const uint8_t *>(buffer); + uint32_t p_crc = *crc; + + if (width < 8) { + uint8_t data_byte; + for (crc_data_size_t byte = 0; byte < size; byte++) { + data_byte = reflect_bytes(data[byte]); + for (uint8_t bit = 8; bit > 0; --bit) { + p_crc <<= 1; + if ((data_byte ^ p_crc) & get_top_bit()) { + p_crc ^= polynomial; + } + data_byte <<= 1; + } + } + } else { + for (crc_data_size_t byte = 0; byte < size; byte++) { + p_crc ^= (reflect_bytes(data[byte]) << (width - 8)); + + // Perform modulo-2 division, a bit at a time + for (uint8_t bit = 8; bit > 0; --bit) { + if (p_crc & get_top_bit()) { + p_crc = (p_crc << 1) ^ polynomial; + } else { + p_crc = (p_crc << 1); + } + } + } + } + *crc = p_crc & get_crc_mask(); + return 0; + } + + /** CRC computation using ROM tables. + * + * @param buffer data buffer + * @param size size of the data + * @param crc CRC value is filled in, but the value is not the final + * @return 0 on success or a negative error code on failure + */ + int32_t table_compute_partial(const void *buffer, crc_data_size_t size, uint32_t *crc) const + { + MBED_ASSERT(crc != NULL); + + const uint8_t *data = static_cast<const uint8_t *>(buffer); + uint32_t p_crc = *crc; + uint8_t data_byte = 0; + + if (width <= 8) { + uint8_t *crc_table = (uint8_t *)_crc_table; + for (crc_data_size_t byte = 0; byte < size; byte++) { + data_byte = reflect_bytes(data[byte]) ^ p_crc; + p_crc = crc_table[data_byte]; + } + } else if (width <= 16) { + uint16_t *crc_table = (uint16_t *)_crc_table; + for (crc_data_size_t byte = 0; byte < size; byte++) { + data_byte = reflect_bytes(data[byte]) ^ (p_crc >> (width - 8)); + p_crc = crc_table[data_byte] ^ (p_crc << 8); + } + } else { + uint32_t *crc_table = (uint32_t *)_crc_table; + if (POLY_32BIT_REV_ANSI == polynomial) { + for (crc_data_size_t i = 0; i < size; i++) { + p_crc = (p_crc >> 4) ^ crc_table[(p_crc ^ (data[i] >> 0)) & 0xf]; + p_crc = (p_crc >> 4) ^ crc_table[(p_crc ^ (data[i] >> 4)) & 0xf]; + } + } + else { + for (crc_data_size_t byte = 0; byte < size; byte++) { + data_byte = reflect_bytes(data[byte]) ^ (p_crc >> (width - 8)); + p_crc = crc_table[data_byte] ^ (p_crc << 8); + } + } + } + *crc = p_crc & get_crc_mask(); + return 0; + } + + /** Constructor init called from all specialized cases of constructor. + * Note: All construtor common code should be in this function. + */ + void mbed_crc_ctor(void) + { + MBED_STATIC_ASSERT(width <= 32, "Max 32-bit CRC supported"); + +#ifdef DEVICE_CRC + if (POLY_32BIT_REV_ANSI == polynomial) { + _crc_table = (uint32_t *)Table_CRC_32bit_Rev_ANSI; + _mode = TABLE; + return; + } + crc_mbed_config_t config; + config.polynomial = polynomial; + config.width = width; + config.initial_xor = _initial_value; + config.final_xor = _final_xor; + config.reflect_in = _reflect_data; + config.reflect_out = _reflect_remainder; + + if (hal_crc_is_supported(&config)) { + _mode = HARDWARE; + return; + } +#endif + + switch (polynomial) { + case POLY_32BIT_ANSI: + _crc_table = (uint32_t *)Table_CRC_32bit_ANSI; + break; + case POLY_32BIT_REV_ANSI: + _crc_table = (uint32_t *)Table_CRC_32bit_Rev_ANSI; + break; + case POLY_8BIT_CCITT: + _crc_table = (uint32_t *)Table_CRC_8bit_CCITT; + break; + case POLY_7BIT_SD: + _crc_table = (uint32_t *)Table_CRC_7Bit_SD; + break; + case POLY_16BIT_CCITT: + _crc_table = (uint32_t *)Table_CRC_16bit_CCITT; + break; + case POLY_16BIT_IBM: + _crc_table = (uint32_t *)Table_CRC_16bit_IBM; + break; + default: + _crc_table = NULL; + break; + } + _mode = (_crc_table != NULL) ? TABLE : BITWISE; + } +}; + +#if defined ( __CC_ARM ) +#elif defined ( __GNUC__ ) +#pragma GCC diagnostic pop +#elif defined (__ICCARM__) +#endif + +/** @}*/ +} // namespace mbed + +#endif