mbed official
mbed library sources. Supersedes mbed-src.
Dependents: Nucleo_Hello_Encoder BLE_iBeaconScan AM1805_DEMO DISCO-F429ZI_ExportTemplate1 ... more
Diff: cmsis/BUILD/mbed/drivers/MbedCRC.h
- Revision:
- 189:f392fc9709a3
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/cmsis/BUILD/mbed/drivers/MbedCRC.h Wed Feb 20 22:31:08 2019 +0000
@@ -0,0 +1,563 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2018 ARM Limited
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * 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 {
+#if 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) {
+#if 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);
+
+#if 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);
+
+#if 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;
+ }
+
+#if !defined(DOXYGEN_ONLY)
+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()
+ {
+#if DEVICE_CRC
+ if (_mode == HARDWARE) {
+ mbed_crc_mutex->lock();
+ }
+#endif
+ }
+
+ /** Release exclusive access to CRC hardware/software.
+ */
+ virtual void unlock()
+ {
+#if 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 constructor common code should be in this function.
+ */
+ void mbed_crc_ctor(void)
+ {
+ MBED_STATIC_ASSERT(width <= 32, "Max 32-bit CRC supported");
+
+#if 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;
+ }
+#endif
+};
+
+#if defined ( __CC_ARM )
+#elif defined ( __GNUC__ )
+#pragma GCC diagnostic pop
+#elif defined (__ICCARM__)
+#endif
+
+/** @}*/
+} // namespace mbed
+
+#endif
