/* * This file is part of the MicroPython project, http://micropython.org/ * * The MIT License (MIT) * * Copyright (c) 2021 Mike Teachman * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ #include #include #include #include #include #include "py/obj.h" #include "py/runtime.h" #include "py/misc.h" #include "py/stream.h" #include "py/objstr.h" #include "modmachine.h" #include "mphalport.h" #if MICROPY_PY_MACHINE_I2S #include "driver/i2s.h" #include "soc/i2s_reg.h" #include "freertos/FreeRTOS.h" #include "freertos/task.h" #include "freertos/queue.h" #include "esp_task.h" // The I2S module has 3 modes of operation: // // Mode1: Blocking // - readinto() and write() methods block until the supplied buffer is filled (read) or emptied (write) // - this is the default mode of operation // // Mode2: Non-Blocking // - readinto() and write() methods return immediately. // - buffer filling and emptying happens asynchronously to the main MicroPython task // - a callback function is called when the supplied buffer has been filled (read) or emptied (write) // - non-blocking mode is enabled when a callback is set with the irq() method // - a FreeRTOS task is created to implement the asynchronous background operations // - a FreeRTOS queue is used to transfer the supplied buffer to the background task // // Mode3: Uasyncio // - implements the stream protocol // - uasyncio mode is enabled when the ioctl() function is called // - the I2S event queue is used to detect that I2S samples can be read or written from/to DMA memory // // The samples contained in the app buffer supplied for the readinto() and write() methods have the following convention: // Mono: little endian format // Stereo: little endian format, left channel first // // I2S terms: // "frame": consists of two audio samples (Left audio sample + Right audio sample) // // Misc: // - for Mono configuration: // - readinto method: samples are gathered from the L channel only // - write method: every sample is output to both the L and R channels // - for readinto method the I2S hardware is read using 8-byte frames // (this is standard for almost all I2S hardware, such as MEMS microphones) // - all sample data transfers use DMA #define I2S_TASK_PRIORITY (ESP_TASK_PRIO_MIN + 1) #define I2S_TASK_STACK_SIZE (2048) #define DMA_BUF_LEN_IN_I2S_FRAMES (256) // The transform buffer is used with the readinto() method to bridge the opaque DMA memory on the ESP devices // with the app buffer. It facilitates audio sample transformations. e.g. 32-bits samples to 16-bit samples. // The size of 240 bytes is an engineering optimum that balances transfer performance with an acceptable use of heap space #define SIZEOF_TRANSFORM_BUFFER_IN_BYTES (240) #define NUM_I2S_USER_FORMATS (4) #define I2S_RX_FRAME_SIZE_IN_BYTES (8) typedef enum { MONO, STEREO } format_t; typedef enum { BLOCKING, NON_BLOCKING, UASYNCIO } io_mode_t; typedef enum { I2S_TX_TRANSFER, I2S_RX_TRANSFER, } direction_t; typedef struct _non_blocking_descriptor_t { mp_buffer_info_t appbuf; mp_obj_t callback; direction_t direction; } non_blocking_descriptor_t; typedef struct _machine_i2s_obj_t { mp_obj_base_t base; i2s_port_t port; mp_hal_pin_obj_t sck; mp_hal_pin_obj_t ws; mp_hal_pin_obj_t sd; int8_t mode; i2s_bits_per_sample_t bits; format_t format; int32_t rate; int32_t ibuf; mp_obj_t callback_for_non_blocking; io_mode_t io_mode; uint8_t transform_buffer[SIZEOF_TRANSFORM_BUFFER_IN_BYTES]; QueueHandle_t i2s_event_queue; QueueHandle_t non_blocking_mode_queue; TaskHandle_t non_blocking_mode_task; } machine_i2s_obj_t; STATIC mp_obj_t machine_i2s_deinit(mp_obj_t self_in); // The frame map is used with the readinto() method to transform the audio sample data coming // from DMA memory (32-bit stereo, with the L and R channels reversed) to the format specified // in the I2S constructor. e.g. 16-bit mono STATIC const int8_t i2s_frame_map[NUM_I2S_USER_FORMATS][I2S_RX_FRAME_SIZE_IN_BYTES] = { { 6, 7, -1, -1, -1, -1, -1, -1 }, // Mono, 16-bits { 4, 5, 6, 7, -1, -1, -1, -1 }, // Mono, 32-bits { 6, 7, 2, 3, -1, -1, -1, -1 }, // Stereo, 16-bits { 4, 5, 6, 7, 0, 1, 2, 3 }, // Stereo, 32-bits }; STATIC machine_i2s_obj_t *machine_i2s_obj[I2S_NUM_MAX]; void machine_i2s_init0() { for (i2s_port_t p = 0; p < I2S_NUM_MAX; p++) { machine_i2s_obj[p] = NULL; } } // The following function takes a sample buffer and swaps L/R channels // // Background: For 32-bit stereo, the ESP-IDF API has a L/R channel orientation that breaks // convention with other ESP32 channel formats // // appbuf[] = [L_0-7, L_8-15, L_16-23, L_24-31, R_0-7, R_8-15, R_16-23, R_24-31] = [Left channel, Right channel] // dma[] = [R_0-7, R_8-15, R_16-23, R_24-31, L_0-7, L_8-15, L_16-23, L_24-31] = [Right channel, Left channel] // // where: // L_0-7 is the least significant byte of the 32 bit sample in the Left channel // L_24-31 is the most significant byte of the 32 bit sample in the Left channel // // Example: // // appbuf[] = [0x99, 0xBB, 0x11, 0x22, 0x44, 0x55, 0xAB, 0x77] = [Left channel, Right channel] // dma[] = [0x44, 0x55, 0xAB, 0x77, 0x99, 0xBB, 0x11, 0x22] = [Right channel, Left channel] // where: // LEFT Channel = 0x99, 0xBB, 0x11, 0x22 // RIGHT Channel = 0x44, 0x55, 0xAB, 0x77 // // samples in appbuf are in little endian format: // 0x77 is the most significant byte of the 32-bit sample // 0x44 is the least significant byte of the 32-bit sample STATIC void swap_32_bit_stereo_channels(mp_buffer_info_t *bufinfo) { int32_t swap_sample; int32_t *sample = bufinfo->buf; uint32_t num_samples = bufinfo->len / 4; for (uint32_t i = 0; i < num_samples; i += 2) { swap_sample = sample[i + 1]; sample[i + 1] = sample[i]; sample[i] = swap_sample; } } STATIC int8_t get_frame_mapping_index(i2s_bits_per_sample_t bits, format_t format) { if (format == MONO) { if (bits == I2S_BITS_PER_SAMPLE_16BIT) { return 0; } else { // 32 bits return 1; } } else { // STEREO if (bits == I2S_BITS_PER_SAMPLE_16BIT) { return 2; } else { // 32 bits return 3; } } } STATIC i2s_bits_per_sample_t get_dma_bits(uint8_t mode, i2s_bits_per_sample_t bits) { if (mode == (I2S_MODE_MASTER | I2S_MODE_TX)) { return bits; } else { // Master Rx // read 32 bit samples for I2S hardware. e.g. MEMS microphones return I2S_BITS_PER_SAMPLE_32BIT; } } STATIC i2s_channel_fmt_t get_dma_format(uint8_t mode, format_t format) { if (mode == (I2S_MODE_MASTER | I2S_MODE_TX)) { if (format == MONO) { return I2S_CHANNEL_FMT_ONLY_LEFT; } else { // STEREO return I2S_CHANNEL_FMT_RIGHT_LEFT; } } else { // Master Rx // read stereo frames for all I2S hardware return I2S_CHANNEL_FMT_RIGHT_LEFT; } } STATIC uint32_t get_dma_buf_count(uint8_t mode, i2s_bits_per_sample_t bits, format_t format, int32_t ibuf) { // calculate how many DMA buffers need to be allocated uint32_t dma_frame_size_in_bytes = (get_dma_bits(mode, bits) / 8) * (get_dma_format(mode, format) == I2S_CHANNEL_FMT_RIGHT_LEFT ? 2: 1); uint32_t dma_buf_count = ibuf / (DMA_BUF_LEN_IN_I2S_FRAMES * dma_frame_size_in_bytes); return dma_buf_count; } STATIC uint32_t fill_appbuf_from_dma(machine_i2s_obj_t *self, mp_buffer_info_t *appbuf) { // copy audio samples from DMA memory to the app buffer // audio samples are read from DMA memory in chunks // loop, reading and copying chunks until the app buffer is filled // For uasyncio mode, the loop will make an early exit if DMA memory becomes empty // Example: // a MicroPython I2S object is configured for 16-bit mono (2 bytes per audio sample). // For every frame coming from DMA (8 bytes), 2 bytes are "cherry picked" and // copied to the supplied app buffer. // Thus, for every 1 byte copied to the app buffer, 4 bytes are read from DMA memory. // If a 8kB app buffer is supplied, 32kB of audio samples is read from DMA memory. uint32_t a_index = 0; uint8_t *app_p = appbuf->buf; uint8_t appbuf_sample_size_in_bytes = (self->bits / 8) * (self->format == STEREO ? 2: 1); uint32_t num_bytes_needed_from_dma = appbuf->len * (I2S_RX_FRAME_SIZE_IN_BYTES / appbuf_sample_size_in_bytes); while (num_bytes_needed_from_dma) { uint32_t num_bytes_requested_from_dma = MIN(sizeof(self->transform_buffer), num_bytes_needed_from_dma); uint32_t num_bytes_received_from_dma = 0; TickType_t delay; if (self->io_mode == UASYNCIO) { delay = 0; // stop i2s_read() operation if DMA memory becomes empty } else { delay = portMAX_DELAY; // block until supplied buffer is filled } // read a chunk of audio samples from DMA memory check_esp_err(i2s_read( self->port, self->transform_buffer, num_bytes_requested_from_dma, &num_bytes_received_from_dma, delay)); // process the transform buffer one frame at a time. // copy selected bytes from the transform buffer into the user supplied appbuf. // Example: // a MicroPython I2S object is configured for 16-bit mono. This configuration associates to // a frame map index of 0 = { 6, 7, -1, -1, -1, -1, -1, -1 } in the i2s_frame_map array // This mapping indicates: // appbuf[x+0] = frame[6] // appbuf[x+1] = frame[7] // frame bytes 0-5 are not used uint32_t t_index = 0; uint8_t f_index = get_frame_mapping_index(self->bits, self->format); while (t_index < num_bytes_received_from_dma) { uint8_t *transform_p = self->transform_buffer + t_index; for (uint8_t i = 0; i < I2S_RX_FRAME_SIZE_IN_BYTES; i++) { int8_t t_to_a_mapping = i2s_frame_map[f_index][i]; if (t_to_a_mapping != -1) { *app_p++ = transform_p[t_to_a_mapping]; a_index++; } t_index++; } } num_bytes_needed_from_dma -= num_bytes_received_from_dma; if ((self->io_mode == UASYNCIO) && (num_bytes_received_from_dma < num_bytes_requested_from_dma)) { // Unable to fill the entire app buffer from DMA memory. This indicates all DMA RX buffers are empty. // Clear the I2S event queue so ioctl() indicates that the I2S object cannot currently // supply more audio samples xQueueReset(self->i2s_event_queue); break; } } return a_index; } STATIC uint32_t copy_appbuf_to_dma(machine_i2s_obj_t *self, mp_buffer_info_t *appbuf) { if ((self->bits == I2S_BITS_PER_SAMPLE_32BIT) && (self->format == STEREO)) { swap_32_bit_stereo_channels(appbuf); } uint32_t num_bytes_written = 0; TickType_t delay; if (self->io_mode == UASYNCIO) { delay = 0; // stop i2s_write() operation if DMA memory becomes full } else { delay = portMAX_DELAY; // block until supplied buffer is emptied } check_esp_err(i2s_write(self->port, appbuf->buf, appbuf->len, &num_bytes_written, delay)); if ((self->io_mode == UASYNCIO) && (num_bytes_written < appbuf->len)) { // Unable to empty the entire app buffer into DMA memory. This indicates all DMA TX buffers are full. // Clear the I2S event queue so ioctl() indicates that the I2S object cannot currently // accept more audio samples xQueueReset(self->i2s_event_queue); // Undo the swap transformation as the buffer has not been completely emptied. // The uasyncio stream writer will use the same buffer in a future write call. if ((self->bits == I2S_BITS_PER_SAMPLE_32BIT) && (self->format == STEREO)) { swap_32_bit_stereo_channels(appbuf); } } return num_bytes_written; } // FreeRTOS task used for non-blocking mode STATIC void task_for_non_blocking_mode(void *self_in) { machine_i2s_obj_t *self = (machine_i2s_obj_t *)self_in; non_blocking_descriptor_t descriptor; for (;;) { if (xQueueReceive(self->non_blocking_mode_queue, &descriptor, portMAX_DELAY)) { if (descriptor.direction == I2S_TX_TRANSFER) { copy_appbuf_to_dma(self, &descriptor.appbuf); } else { // RX fill_appbuf_from_dma(self, &descriptor.appbuf); } mp_sched_schedule(descriptor.callback, MP_OBJ_FROM_PTR(self)); } } } STATIC void machine_i2s_init_helper(machine_i2s_obj_t *self, size_t n_pos_args, const mp_obj_t *pos_args, mp_map_t *kw_args) { enum { ARG_sck, ARG_ws, ARG_sd, ARG_mode, ARG_bits, ARG_format, ARG_rate, ARG_ibuf, }; static const mp_arg_t allowed_args[] = { { MP_QSTR_sck, MP_ARG_KW_ONLY | MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} }, { MP_QSTR_ws, MP_ARG_KW_ONLY | MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} }, { MP_QSTR_sd, MP_ARG_KW_ONLY | MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} }, { MP_QSTR_mode, MP_ARG_KW_ONLY | MP_ARG_REQUIRED | MP_ARG_INT, {.u_int = -1} }, { MP_QSTR_bits, MP_ARG_KW_ONLY | MP_ARG_REQUIRED | MP_ARG_INT, {.u_int = -1} }, { MP_QSTR_format, MP_ARG_KW_ONLY | MP_ARG_REQUIRED | MP_ARG_INT, {.u_int = -1} }, { MP_QSTR_rate, MP_ARG_KW_ONLY | MP_ARG_REQUIRED | MP_ARG_INT, {.u_int = -1} }, { MP_QSTR_ibuf, MP_ARG_KW_ONLY | MP_ARG_REQUIRED | MP_ARG_INT, {.u_int = -1} }, }; mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)]; mp_arg_parse_all(n_pos_args, pos_args, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args); // // ---- Check validity of arguments ---- // // are Pins valid? int8_t sck = args[ARG_sck].u_obj == MP_OBJ_NULL ? -1 : mp_hal_get_pin_obj(args[ARG_sck].u_obj); int8_t ws = args[ARG_ws].u_obj == MP_OBJ_NULL ? -1 : mp_hal_get_pin_obj(args[ARG_ws].u_obj); int8_t sd = args[ARG_sd].u_obj == MP_OBJ_NULL ? -1 : mp_hal_get_pin_obj(args[ARG_sd].u_obj); // is Mode valid? i2s_mode_t mode = args[ARG_mode].u_int; if ((mode != (I2S_MODE_MASTER | I2S_MODE_RX)) && (mode != (I2S_MODE_MASTER | I2S_MODE_TX))) { mp_raise_ValueError(MP_ERROR_TEXT("invalid mode")); } // is Bits valid? i2s_bits_per_sample_t bits = args[ARG_bits].u_int; if ((bits != I2S_BITS_PER_SAMPLE_16BIT) && (bits != I2S_BITS_PER_SAMPLE_32BIT)) { mp_raise_ValueError(MP_ERROR_TEXT("invalid bits")); } // is Format valid? format_t format = args[ARG_format].u_int; if ((format != STEREO) && (format != MONO)) { mp_raise_ValueError(MP_ERROR_TEXT("invalid format")); } // is Rate valid? // Not checked: ESP-IDF I2S API does not indicate a valid range for sample rate // is Ibuf valid? // Not checked: ESP-IDF I2S API will return error if requested buffer size exceeds available memory self->sck = sck; self->ws = ws; self->sd = sd; self->mode = mode; self->bits = bits; self->format = format; self->rate = args[ARG_rate].u_int; self->ibuf = args[ARG_ibuf].u_int; self->callback_for_non_blocking = MP_OBJ_NULL; self->i2s_event_queue = NULL; self->non_blocking_mode_queue = NULL; self->non_blocking_mode_task = NULL; self->io_mode = BLOCKING; i2s_config_t i2s_config; i2s_config.communication_format = I2S_COMM_FORMAT_I2S; i2s_config.mode = mode; i2s_config.bits_per_sample = get_dma_bits(mode, bits); i2s_config.channel_format = get_dma_format(mode, format); i2s_config.sample_rate = self->rate; i2s_config.intr_alloc_flags = ESP_INTR_FLAG_LOWMED; i2s_config.dma_buf_count = get_dma_buf_count(mode, bits, format, self->ibuf); i2s_config.dma_buf_len = DMA_BUF_LEN_IN_I2S_FRAMES; i2s_config.use_apll = false; // I2S queue size equals the number of DMA buffers check_esp_err(i2s_driver_install(self->port, &i2s_config, i2s_config.dma_buf_count, &self->i2s_event_queue)); // apply low-level workaround for bug in some ESP-IDF versions that swap // the left and right channels // https://github.com/espressif/esp-idf/issues/6625 REG_SET_BIT(I2S_CONF_REG(self->port), I2S_TX_MSB_RIGHT); REG_SET_BIT(I2S_CONF_REG(self->port), I2S_RX_MSB_RIGHT); i2s_pin_config_t pin_config; pin_config.bck_io_num = self->sck; pin_config.ws_io_num = self->ws; if (mode == (I2S_MODE_MASTER | I2S_MODE_RX)) { pin_config.data_in_num = self->sd; pin_config.data_out_num = -1; } else { // TX pin_config.data_in_num = -1; pin_config.data_out_num = self->sd; } check_esp_err(i2s_set_pin(self->port, &pin_config)); } STATIC void machine_i2s_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) { machine_i2s_obj_t *self = MP_OBJ_TO_PTR(self_in); mp_printf(print, "I2S(id=%u,\n" "sck="MP_HAL_PIN_FMT ",\n" "ws="MP_HAL_PIN_FMT ",\n" "sd="MP_HAL_PIN_FMT ",\n" "mode=%u,\n" "bits=%u, format=%u,\n" "rate=%d, ibuf=%d)", self->port, mp_hal_pin_name(self->sck), mp_hal_pin_name(self->ws), mp_hal_pin_name(self->sd), self->mode, self->bits, self->format, self->rate, self->ibuf ); } STATIC mp_obj_t machine_i2s_make_new(const mp_obj_type_t *type, size_t n_pos_args, size_t n_kw_args, const mp_obj_t *args) { mp_arg_check_num(n_pos_args, n_kw_args, 1, MP_OBJ_FUN_ARGS_MAX, true); i2s_port_t port = mp_obj_get_int(args[0]); if (port < 0 || port >= I2S_NUM_MAX) { mp_raise_ValueError(MP_ERROR_TEXT("invalid id")); } machine_i2s_obj_t *self; if (machine_i2s_obj[port] == NULL) { self = m_new_obj(machine_i2s_obj_t); machine_i2s_obj[port] = self; self->base.type = &machine_i2s_type; self->port = port; } else { self = machine_i2s_obj[port]; machine_i2s_deinit(self); } mp_map_t kw_args; mp_map_init_fixed_table(&kw_args, n_kw_args, args + n_pos_args); machine_i2s_init_helper(self, n_pos_args - 1, args + 1, &kw_args); return MP_OBJ_FROM_PTR(self); } STATIC mp_obj_t machine_i2s_obj_init(mp_uint_t n_pos_args, const mp_obj_t *pos_args, mp_map_t *kw_args) { machine_i2s_obj_t *self = pos_args[0]; machine_i2s_deinit(self); machine_i2s_init_helper(self, n_pos_args - 1, pos_args + 1, kw_args); return mp_const_none; } STATIC MP_DEFINE_CONST_FUN_OBJ_KW(machine_i2s_init_obj, 1, machine_i2s_obj_init); STATIC mp_obj_t machine_i2s_deinit(mp_obj_t self_in) { machine_i2s_obj_t *self = MP_OBJ_TO_PTR(self_in); i2s_driver_uninstall(self->port); if (self->non_blocking_mode_task != NULL) { vTaskDelete(self->non_blocking_mode_task); self->non_blocking_mode_task = NULL; } if (self->non_blocking_mode_queue != NULL) { vQueueDelete(self->non_blocking_mode_queue); self->non_blocking_mode_queue = NULL; } self->i2s_event_queue = NULL; return mp_const_none; } STATIC MP_DEFINE_CONST_FUN_OBJ_1(machine_i2s_deinit_obj, machine_i2s_deinit); STATIC mp_obj_t machine_i2s_irq(mp_obj_t self_in, mp_obj_t handler) { machine_i2s_obj_t *self = MP_OBJ_TO_PTR(self_in); if (handler != mp_const_none && !mp_obj_is_callable(handler)) { mp_raise_ValueError(MP_ERROR_TEXT("invalid callback")); } if (handler != mp_const_none) { self->io_mode = NON_BLOCKING; // create a queue linking the MicroPython task to a FreeRTOS task // that manages the non blocking mode of operation self->non_blocking_mode_queue = xQueueCreate(1, sizeof(non_blocking_descriptor_t)); // non-blocking mode requires a background FreeRTOS task if (xTaskCreatePinnedToCore( task_for_non_blocking_mode, "i2s_non_blocking", I2S_TASK_STACK_SIZE, self, I2S_TASK_PRIORITY, (TaskHandle_t *)&self->non_blocking_mode_task, MP_TASK_COREID) != pdPASS) { mp_raise_msg(&mp_type_RuntimeError, MP_ERROR_TEXT("failed to create I2S task")); } } else { if (self->non_blocking_mode_task != NULL) { vTaskDelete(self->non_blocking_mode_task); self->non_blocking_mode_task = NULL; } if (self->non_blocking_mode_queue != NULL) { vQueueDelete(self->non_blocking_mode_queue); self->non_blocking_mode_queue = NULL; } self->io_mode = BLOCKING; } self->callback_for_non_blocking = handler; return mp_const_none; } STATIC MP_DEFINE_CONST_FUN_OBJ_2(machine_i2s_irq_obj, machine_i2s_irq); // Shift() is typically used as a volume control. // shift=1 increases volume by 6dB, shift=-1 decreases volume by 6dB STATIC mp_obj_t machine_i2s_shift(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) { enum { ARG_buf, ARG_bits, ARG_shift}; static const mp_arg_t allowed_args[] = { { MP_QSTR_buf, MP_ARG_REQUIRED | MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = mp_const_none} }, { MP_QSTR_bits, MP_ARG_REQUIRED | MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} }, { MP_QSTR_shift, MP_ARG_REQUIRED | MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} }, }; // parse args mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)]; mp_arg_parse_all(n_args, pos_args, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args); mp_buffer_info_t bufinfo; mp_get_buffer_raise(args[ARG_buf].u_obj, &bufinfo, MP_BUFFER_RW); int16_t *buf_16 = bufinfo.buf; int32_t *buf_32 = bufinfo.buf; uint8_t bits = args[ARG_bits].u_int; int8_t shift = args[ARG_shift].u_int; uint32_t num_audio_samples; switch (bits) { case 16: num_audio_samples = bufinfo.len / 2; break; case 32: num_audio_samples = bufinfo.len / 4; break; default: mp_raise_ValueError(MP_ERROR_TEXT("invalid bits")); break; } for (uint32_t i = 0; i < num_audio_samples; i++) { switch (bits) { case 16: if (shift >= 0) { buf_16[i] = buf_16[i] << shift; } else { buf_16[i] = buf_16[i] >> abs(shift); } break; case 32: if (shift >= 0) { buf_32[i] = buf_32[i] << shift; } else { buf_32[i] = buf_32[i] >> abs(shift); } break; } } return mp_const_none; } STATIC MP_DEFINE_CONST_FUN_OBJ_KW(machine_i2s_shift_fun_obj, 0, machine_i2s_shift); STATIC MP_DEFINE_CONST_STATICMETHOD_OBJ(machine_i2s_shift_obj, MP_ROM_PTR(&machine_i2s_shift_fun_obj)); STATIC const mp_rom_map_elem_t machine_i2s_locals_dict_table[] = { // Methods { MP_ROM_QSTR(MP_QSTR_init), MP_ROM_PTR(&machine_i2s_init_obj) }, { MP_ROM_QSTR(MP_QSTR_readinto), MP_ROM_PTR(&mp_stream_readinto_obj) }, { MP_ROM_QSTR(MP_QSTR_write), MP_ROM_PTR(&mp_stream_write_obj) }, { MP_ROM_QSTR(MP_QSTR_deinit), MP_ROM_PTR(&machine_i2s_deinit_obj) }, { MP_ROM_QSTR(MP_QSTR_irq), MP_ROM_PTR(&machine_i2s_irq_obj) }, // Static method { MP_ROM_QSTR(MP_QSTR_shift), MP_ROM_PTR(&machine_i2s_shift_obj) }, // Constants { MP_ROM_QSTR(MP_QSTR_RX), MP_ROM_INT(I2S_MODE_MASTER | I2S_MODE_RX) }, { MP_ROM_QSTR(MP_QSTR_TX), MP_ROM_INT(I2S_MODE_MASTER | I2S_MODE_TX) }, { MP_ROM_QSTR(MP_QSTR_STEREO), MP_ROM_INT(STEREO) }, { MP_ROM_QSTR(MP_QSTR_MONO), MP_ROM_INT(MONO) }, }; MP_DEFINE_CONST_DICT(machine_i2s_locals_dict, machine_i2s_locals_dict_table); STATIC mp_uint_t machine_i2s_stream_read(mp_obj_t self_in, void *buf_in, mp_uint_t size, int *errcode) { machine_i2s_obj_t *self = MP_OBJ_TO_PTR(self_in); if (self->mode != (I2S_MODE_MASTER | I2S_MODE_RX)) { *errcode = MP_EPERM; return MP_STREAM_ERROR; } uint8_t appbuf_sample_size_in_bytes = (self->bits / 8) * (self->format == STEREO ? 2: 1); if (size % appbuf_sample_size_in_bytes != 0) { *errcode = MP_EINVAL; return MP_STREAM_ERROR; } if (size == 0) { return 0; } if (self->io_mode == NON_BLOCKING) { non_blocking_descriptor_t descriptor; descriptor.appbuf.buf = (void *)buf_in; descriptor.appbuf.len = size; descriptor.callback = self->callback_for_non_blocking; descriptor.direction = I2S_RX_TRANSFER; // send the descriptor to the task that handles non-blocking mode xQueueSend(self->non_blocking_mode_queue, &descriptor, 0); return size; } else { // blocking or uasyncio mode mp_buffer_info_t appbuf; appbuf.buf = (void *)buf_in; appbuf.len = size; uint32_t num_bytes_read = fill_appbuf_from_dma(self, &appbuf); return num_bytes_read; } } STATIC mp_uint_t machine_i2s_stream_write(mp_obj_t self_in, const void *buf_in, mp_uint_t size, int *errcode) { machine_i2s_obj_t *self = MP_OBJ_TO_PTR(self_in); if (self->mode != (I2S_MODE_MASTER | I2S_MODE_TX)) { *errcode = MP_EPERM; return MP_STREAM_ERROR; } if (size == 0) { return 0; } if (self->io_mode == NON_BLOCKING) { non_blocking_descriptor_t descriptor; descriptor.appbuf.buf = (void *)buf_in; descriptor.appbuf.len = size; descriptor.callback = self->callback_for_non_blocking; descriptor.direction = I2S_TX_TRANSFER; // send the descriptor to the task that handles non-blocking mode xQueueSend(self->non_blocking_mode_queue, &descriptor, 0); return size; } else { // blocking or uasyncio mode mp_buffer_info_t appbuf; appbuf.buf = (void *)buf_in; appbuf.len = size; uint32_t num_bytes_written = copy_appbuf_to_dma(self, &appbuf); return num_bytes_written; } } STATIC mp_uint_t machine_i2s_ioctl(mp_obj_t self_in, mp_uint_t request, mp_uint_t arg, int *errcode) { machine_i2s_obj_t *self = MP_OBJ_TO_PTR(self_in); mp_uint_t ret; mp_uint_t flags = arg; self->io_mode = UASYNCIO; // a call to ioctl() is an indication that uasyncio is being used if (request == MP_STREAM_POLL) { ret = 0; if (flags & MP_STREAM_POLL_RD) { if (self->mode != (I2S_MODE_MASTER | I2S_MODE_RX)) { *errcode = MP_EPERM; return MP_STREAM_ERROR; } i2s_event_t i2s_event; // check event queue to determine if a DMA buffer has been filled // (which is an indication that at least one DMA buffer is available to be read) // note: timeout = 0 so the call is non-blocking if (xQueueReceive(self->i2s_event_queue, &i2s_event, 0)) { if (i2s_event.type == I2S_EVENT_RX_DONE) { // getting here means that at least one DMA buffer is now full // indicating that audio samples can be read from the I2S object ret |= MP_STREAM_POLL_RD; } } } if (flags & MP_STREAM_POLL_WR) { if (self->mode != (I2S_MODE_MASTER | I2S_MODE_TX)) { *errcode = MP_EPERM; return MP_STREAM_ERROR; } i2s_event_t i2s_event; // check event queue to determine if a DMA buffer has been emptied // (which is an indication that at least one DMA buffer is available to be written) // note: timeout = 0 so the call is non-blocking if (xQueueReceive(self->i2s_event_queue, &i2s_event, 0)) { if (i2s_event.type == I2S_EVENT_TX_DONE) { // getting here means that at least one DMA buffer is now empty // indicating that audio samples can be written to the I2S object ret |= MP_STREAM_POLL_WR; } } } } else { *errcode = MP_EINVAL; ret = MP_STREAM_ERROR; } return ret; } STATIC const mp_stream_p_t i2s_stream_p = { .read = machine_i2s_stream_read, .write = machine_i2s_stream_write, .ioctl = machine_i2s_ioctl, .is_text = false, }; const mp_obj_type_t machine_i2s_type = { { &mp_type_type }, .name = MP_QSTR_I2S, .print = machine_i2s_print, .getiter = mp_identity_getiter, .iternext = mp_stream_unbuffered_iter, .protocol = &i2s_stream_p, .make_new = machine_i2s_make_new, .locals_dict = (mp_obj_dict_t *)&machine_i2s_locals_dict, }; #endif // MICROPY_PY_MACHINE_I2S