feat(driver): BitScrambler support

This adds an assembler for the BitScrambler assembly language,
plus unit tests for it. It also adds the loopback driver,
which can do BitScrambler operations on memory-to-memory
transfers. Documentation is also included.

components/esp_driver_bitscrambler/include/driver/bitscrambler_loopback.h

@@ -0,0 +1,58 @@
+/*
+ * SPDX-FileCopyrightText: 2024 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+#pragma once
+
+#include "driver/bitscrambler.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief Create handle for BitScrambler in loopback mode
+ *
+ * @note Use bitscrambler_free to free created handle.
+ *
+ * @param[out] handle BitScrambler handle
+ * @param attach_to Peripheral to attach to. One of SOC_BITSCRAMBLER_ATTACH_. The BitScrambler
+ *        must be attached to some peripheral, even in loopback mode. This peripheral does not
+ *        need to be initialized for the BitScrambler to work. However, it can be initialized
+ *        and will work as normal, with the exception that DMA functionality for this peripheral
+ *        cannot be used.
+ * @param max_transfer_sz_bytes Maximum transfer size, in bytes, of either the incoming or outgoing data
+ *        fed to bitscrambler_loopback_run.
+ *
+ * @returns
+ *        - ESP_OK
+ *        - ESP_ERR_NO_MEM: No memory available
+ *        - ESP_ERR_NOT_FOUND: No free hardware channel available
+ *        - ESP_ERR_INVALID_ARG: Invalid argument passed to function
+ *        - ESP_FAIL: Bitscrambler object creation failed because of some other error
+ */
+esp_err_t bitscrambler_loopback_create(bitscrambler_handle_t *handle, int attach_to, size_t max_transfer_sz_bytes);
+
+/**
+ * @brief Run Bitscrambler program on a data buffer
+ *
+ * @param bs BitScrambler handle. This BitScrambler should have a program loaded using
+ *           bitscrambler_load_program()
+ * @param buffer_in Data to feed into the BitScrambler
+ * @param length_bytes_in Size of the data in buffer_in, in bytes
+ * @param buffer_out Buffer for BitScrambler to write processed data to
+ * @param length_bytes_out Size of output buffer
+ * @param[out] bytes_written Pointer to variable to store the size of actual data written
+ *                           to output buffer. Can be NULL if not needed.
+ *
+ * @returns
+ *        - ESP_OK
+ *        - ESP_ERR_INVALID_SIZE if a buffer size exceeds max_transfer_sz_bytes
+ *        - ESP_ERR_TIMEOUT if BitScrambler program does not complete
+ */
+esp_err_t bitscrambler_loopback_run(bitscrambler_handle_t bs, void *buffer_in, size_t length_bytes_in, void *buffer_out, size_t length_bytes_out, size_t *bytes_written);
+
+#ifdef __cplusplus
+}
+#endif