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micropython/ports/mimxrt/machine_i2s.c

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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2022 Mike Teachman
* Copyright (c) 2022 Robert Hammelrath
*
* 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 <stdio.h>
#include <stdint.h>
#include <string.h>
#include <stdlib.h>
#include <stdbool.h>
#include "py/obj.h"
#include "py/runtime.h"
#include "py/mphal.h"
#include "py/misc.h"
#include "py/stream.h"
#include "py/objstr.h"
#include "modmachine.h"
#include "dma_manager.h"
#include CLOCK_CONFIG_H
#include "fsl_iomuxc.h"
#include "fsl_dmamux.h"
#include "fsl_edma.h"
#include "fsl_sai.h"
#if MICROPY_PY_MACHINE_I2S
// 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
// - the DMA callback is used to implement the asynchronous background operations
//
// Mode3: Uasyncio
// - implements the stream protocol
// - uasyncio mode is enabled when the ioctl() function is called
// - the state of the internal ring buffer is used to detect that I2S samples can be read or written
//
// 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 3 Modes of operation are implemented using the peripheral drivers in the NXP MCUXpresso SDK
// - all sample data transfers use DMA
// - the DMA ping-pong buffer needs to be aligned to a cache line size of 32 bytes. 32 byte
// alignment is needed to use the routines that clean and invalidate D-Cache which work on a
// 32 byte address boundary.
// - master clock frequency is sampling frequency * 256
// DMA ping-pong buffer size was empirically determined. It is a tradeoff between:
// 1. memory use (smaller buffer size desirable to reduce memory footprint)
// 2. interrupt frequency (larger buffer size desirable to reduce interrupt frequency)
// The sizeof 1/2 of the DMA buffer must be evenly divisible by the cache line size of 32 bytes.
#define SIZEOF_DMA_BUFFER_IN_BYTES (256)
#define SIZEOF_HALF_DMA_BUFFER_IN_BYTES (SIZEOF_DMA_BUFFER_IN_BYTES / 2)
// For non-blocking mode, to avoid underflow/overflow, sample data is written/read to/from the ring buffer at a rate faster
// than the DMA transfer rate
#define NON_BLOCKING_RATE_MULTIPLIER (4)
#define SIZEOF_NON_BLOCKING_COPY_IN_BYTES (SIZEOF_HALF_DMA_BUFFER_IN_BYTES * NON_BLOCKING_RATE_MULTIPLIER)
#define NUM_I2S_USER_FORMATS (4)
#define I2S_RX_FRAME_SIZE_IN_BYTES (8)
#define AUDIO_PLL_CLOCK (2U)
#define SAI_CHANNEL_0 (0)
#define SAI_NUM_AUDIO_CHANNELS (2U)
typedef enum {
SCK,
WS,
SD,
MCK
} i2s_pin_function_t;
typedef enum {
RX,
TX,
} i2s_mode_t;
typedef enum {
MONO,
STEREO
} format_t;
typedef enum {
BLOCKING,
NON_BLOCKING,
UASYNCIO
} io_mode_t;
typedef enum {
TOP_HALF,
BOTTOM_HALF
} ping_pong_t;
typedef struct _ring_buf_t {
uint8_t *buffer;
size_t head;
size_t tail;
size_t size;
} ring_buf_t;
typedef struct _non_blocking_descriptor_t {
mp_buffer_info_t appbuf;
uint32_t index;
bool copy_in_progress;
} non_blocking_descriptor_t;
typedef struct _machine_i2s_obj_t {
mp_obj_base_t base;
uint8_t i2s_id;
mp_hal_pin_obj_t sck;
mp_hal_pin_obj_t ws;
mp_hal_pin_obj_t sd;
mp_hal_pin_obj_t mck;
i2s_mode_t mode;
int8_t bits;
format_t format;
int32_t rate;
int32_t ibuf;
mp_obj_t callback_for_non_blocking;
uint8_t dma_buffer[SIZEOF_DMA_BUFFER_IN_BYTES + 0x1f]; // 0x1f related to D-Cache alignment
uint8_t *dma_buffer_dcache_aligned;
ring_buf_t ring_buffer;
uint8_t *ring_buffer_storage;
non_blocking_descriptor_t non_blocking_descriptor;
io_mode_t io_mode;
I2S_Type *i2s_inst;
int dma_channel;
edma_handle_t edmaHandle;
edma_tcd_t *edmaTcd;
} machine_i2s_obj_t;
typedef struct _iomux_table_t {
uint32_t muxRegister;
uint32_t muxMode;
uint32_t inputRegister;
uint32_t inputDaisy;
uint32_t configRegister;
} iomux_table_t;
typedef struct _gpio_map_t {
uint8_t hw_id;
i2s_pin_function_t fn;
i2s_mode_t mode;
qstr name;
iomux_table_t iomux;
} gpio_map_t;
typedef struct _i2s_clock_config_t {
sai_sample_rate_t rate;
const clock_audio_pll_config_t *pll_config;
uint32_t clock_pre_divider;
uint32_t clock_divider;
} i2s_clock_config_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) 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] = {
{-1, -1, 0, 1, -1, -1, -1, -1 }, // Mono, 16-bits
{ 0, 1, 2, 3, -1, -1, -1, -1 }, // Mono, 32-bits
{-1, -1, 0, 1, -1, -1, 2, 3 }, // Stereo, 16-bits
{ 0, 1, 2, 3, 4, 5, 6, 7 }, // Stereo, 32-bits
};
// 2 PLL configurations
// PLL output frequency = 24MHz * (.loopDivider + .numerator/.denominator)
// Configuration 1: for sampling frequencies [Hz]: 8000, 12000, 16000, 24000, 32000, 48000
// Clock frequency = 786,432,480 Hz
STATIC const clock_audio_pll_config_t audioPllConfig_8000_48000 = {
.loopDivider = 32, // PLL loop divider. Valid range for DIV_SELECT divider value: 27~54
.postDivider = 1, // Divider after the PLL, should only be 1, 2, 4, 8, 16
.numerator = 76802, // 30 bit numerator of fractional loop divider
.denominator = 100000, // 30 bit denominator of fractional loop divider
.src = kCLOCK_PllClkSrc24M // Pll clock source
};
// Configuration 2: for sampling frequencies [Hz]: 11025, 22050, 44100
// Clock frequency = 722,534,880
STATIC const clock_audio_pll_config_t audioPllConfig_11025_44100 = {
.loopDivider = 30, // PLL loop divider. Valid range for DIV_SELECT divider value: 27~54
.postDivider = 1, // Divider after the PLL, should only be 1, 2, 4, 8, 16
.numerator = 10562, // 30 bit numerator of fractional loop divider
.denominator = 100000, // 30 bit denominator of fractional loop divider
.src = kCLOCK_PllClkSrc24M // Pll clock source
};
STATIC const i2s_clock_config_t clock_config_map[] = {
{kSAI_SampleRate8KHz, &audioPllConfig_8000_48000, 5, 63},
{kSAI_SampleRate11025Hz, &audioPllConfig_11025_44100, 3, 63},
{kSAI_SampleRate12KHz, &audioPllConfig_8000_48000, 3, 63},
{kSAI_SampleRate16KHz, &audioPllConfig_8000_48000, 2, 63},
{kSAI_SampleRate22050Hz, &audioPllConfig_11025_44100, 1, 63},
{kSAI_SampleRate24KHz, &audioPllConfig_8000_48000, 1, 63},
{kSAI_SampleRate32KHz, &audioPllConfig_8000_48000, 1, 47},
{kSAI_SampleRate44100Hz, &audioPllConfig_11025_44100, 0, 63},
{kSAI_SampleRate48KHz, &audioPllConfig_8000_48000, 0, 63}
};
STATIC const I2S_Type *i2s_base_ptr[] = I2S_BASE_PTRS;
STATIC const clock_mux_t i2s_clock_mux[] = I2S_CLOCK_MUX;
STATIC const clock_div_t i2s_clock_pre_div[] = I2S_CLOCK_PRE_DIV;
STATIC const clock_div_t i2s_clock_div[] = I2S_CLOCK_DIV;
STATIC const iomuxc_gpr_mode_t i2s_iomuxc_gpr_mode[] = I2S_IOMUXC_GPR_MODE;
STATIC const dma_request_source_t i2s_dma_req_src_tx[] = I2S_DMA_REQ_SRC_TX;
STATIC const dma_request_source_t i2s_dma_req_src_rx[] = I2S_DMA_REQ_SRC_RX;
STATIC const gpio_map_t i2s_gpio_map[] = I2S_GPIO_MAP;
AT_NONCACHEABLE_SECTION_ALIGN(STATIC edma_tcd_t edmaTcd[MICROPY_HW_I2S_NUM], 32);
// called on processor reset
void machine_i2s_init0() {
for (uint8_t i = 0; i < MICROPY_HW_I2S_NUM; i++) {
MP_STATE_PORT(machine_i2s_obj)[i] = NULL;
}
}
// called on soft reboot
void machine_i2s_deinit_all(void) {
for (uint8_t i = 0; i < MICROPY_HW_I2S_NUM; i++) {
machine_i2s_obj_t *i2s_obj = MP_STATE_PORT(machine_i2s_obj)[i];
if (i2s_obj != NULL) {
machine_i2s_deinit(i2s_obj);
MP_STATE_PORT(machine_i2s_obj)[i] = NULL;
}
}
}
// Ring Buffer
// Thread safe when used with these constraints:
// - Single Producer, Single Consumer
// - Sequential atomic operations
// One byte of capacity is used to detect buffer empty/full
STATIC void ringbuf_init(ring_buf_t *rbuf, uint8_t *buffer, size_t size) {
rbuf->buffer = buffer;
rbuf->size = size;
rbuf->head = 0;
rbuf->tail = 0;
}
STATIC bool ringbuf_push(ring_buf_t *rbuf, uint8_t data) {
size_t next_tail = (rbuf->tail + 1) % rbuf->size;
if (next_tail != rbuf->head) {
rbuf->buffer[rbuf->tail] = data;
rbuf->tail = next_tail;
return true;
}
// full
return false;
}
STATIC bool ringbuf_pop(ring_buf_t *rbuf, uint8_t *data) {
if (rbuf->head == rbuf->tail) {
// empty
return false;
}
*data = rbuf->buffer[rbuf->head];
rbuf->head = (rbuf->head + 1) % rbuf->size;
return true;
}
STATIC bool ringbuf_is_empty(ring_buf_t *rbuf) {
return rbuf->head == rbuf->tail;
}
STATIC bool ringbuf_is_full(ring_buf_t *rbuf) {
return ((rbuf->tail + 1) % rbuf->size) == rbuf->head;
}
STATIC size_t ringbuf_available_data(ring_buf_t *rbuf) {
return (rbuf->tail - rbuf->head + rbuf->size) % rbuf->size;
}
STATIC size_t ringbuf_available_space(ring_buf_t *rbuf) {
return rbuf->size - ringbuf_available_data(rbuf) - 1;
}
STATIC int8_t get_frame_mapping_index(int8_t bits, format_t format) {
if (format == MONO) {
if (bits == 16) {
return 0;
} else { // 32 bits
return 1;
}
} else { // STEREO
if (bits == 16) {
return 2;
} else { // 32 bits
return 3;
}
}
}
STATIC int8_t get_dma_bits(uint16_t mode, int8_t bits) {
if (mode == TX) {
if (bits == 16) {
return 16;
} else {
return 32;
}
return bits;
} else { // RX
// always read 32 bit words for I2S e.g. I2S MEMS microphones
return 32;
}
}
STATIC bool lookup_gpio(const machine_pin_obj_t *pin, i2s_pin_function_t fn, uint8_t hw_id, uint16_t *index) {
for (uint16_t i = 0; i < ARRAY_SIZE(i2s_gpio_map); i++) {
if ((pin->name == i2s_gpio_map[i].name) &&
(i2s_gpio_map[i].fn == fn) &&
(i2s_gpio_map[i].hw_id == hw_id)) {
*index = i;
return true;
}
}
return false;
}
STATIC bool set_iomux(const machine_pin_obj_t *pin, i2s_pin_function_t fn, uint8_t hw_id) {
uint16_t mapping_index;
if (lookup_gpio(pin, fn, hw_id, &mapping_index)) {
iomux_table_t iom = i2s_gpio_map[mapping_index].iomux;
IOMUXC_SetPinMux(iom.muxRegister, iom.muxMode, iom.inputRegister, iom.inputDaisy, iom.configRegister, 1U);
IOMUXC_SetPinConfig(iom.muxRegister, iom.muxMode, iom.inputRegister, iom.inputDaisy, iom.configRegister,
pin_generate_config(PIN_PULL_DISABLED, PIN_MODE_OUT, 2, iom.configRegister));
return true;
} else {
return false;
}
}
STATIC bool is_rate_supported(int32_t rate) {
for (uint16_t i = 0; i < ARRAY_SIZE(clock_config_map); i++) {
if (clock_config_map[i].rate == rate) {
return true;
}
}
return false;
}
STATIC const clock_audio_pll_config_t *get_pll_config(int32_t rate) {
for (uint16_t i = 0; i < ARRAY_SIZE(clock_config_map); i++) {
if (clock_config_map[i].rate == rate) {
return clock_config_map[i].pll_config;
}
}
return 0;
}
STATIC const uint32_t get_clock_pre_divider(int32_t rate) {
for (uint16_t i = 0; i < ARRAY_SIZE(clock_config_map); i++) {
if (clock_config_map[i].rate == rate) {
return clock_config_map[i].clock_pre_divider;
}
}
return 0;
}
STATIC const uint32_t get_clock_divider(int32_t rate) {
for (uint16_t i = 0; i < ARRAY_SIZE(clock_config_map); i++) {
if (clock_config_map[i].rate == rate) {
return clock_config_map[i].clock_divider;
}
}
return 0;
}
STATIC uint32_t fill_appbuf_from_ringbuf(machine_i2s_obj_t *self, mp_buffer_info_t *appbuf) {
// copy audio samples from the ring buffer to the app buffer
// loop, copying samples until the app buffer is filled
// For uasyncio mode, the loop will make an early exit if the ring buffer becomes empty
// Example:
// a MicroPython I2S object is configured for 16-bit mono (2 bytes per audio sample).
// For every frame coming from the ring buffer (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 the ring buffer.
// If a 8kB app buffer is supplied, 32kB of audio samples is read from the ring buffer.
uint32_t num_bytes_copied_to_appbuf = 0;
uint8_t *app_p = (uint8_t *)appbuf->buf;
uint8_t appbuf_sample_size_in_bytes = (self->bits == 16? 2 : 4) * (self->format == STEREO ? 2: 1);
uint32_t num_bytes_needed_from_ringbuf = appbuf->len * (I2S_RX_FRAME_SIZE_IN_BYTES / appbuf_sample_size_in_bytes);
uint8_t discard_byte;
while (num_bytes_needed_from_ringbuf) {
uint8_t f_index = get_frame_mapping_index(self->bits, self->format);
for (uint8_t i = 0; i < I2S_RX_FRAME_SIZE_IN_BYTES; i++) {
int8_t r_to_a_mapping = i2s_frame_map[f_index][i];
if (r_to_a_mapping != -1) {
if (self->io_mode == BLOCKING) {
// poll the ringbuf until a sample becomes available, copy into appbuf using the mapping transform
while (ringbuf_pop(&self->ring_buffer, app_p + r_to_a_mapping) == false) {
;
}
num_bytes_copied_to_appbuf++;
} else if (self->io_mode == UASYNCIO) {
if (ringbuf_pop(&self->ring_buffer, app_p + r_to_a_mapping) == false) {
// ring buffer is empty, exit
goto exit;
} else {
num_bytes_copied_to_appbuf++;
}
} else {
return 0; // should never get here (non-blocking mode does not use this function)
}
} else { // r_a_mapping == -1
// discard unused byte from ring buffer
if (self->io_mode == BLOCKING) {
// poll the ringbuf until a sample becomes available
while (ringbuf_pop(&self->ring_buffer, &discard_byte) == false) {
;
}
} else if (self->io_mode == UASYNCIO) {
if (ringbuf_pop(&self->ring_buffer, &discard_byte) == false) {
// ring buffer is empty, exit
goto exit;
}
} else {
return 0; // should never get here (non-blocking mode does not use this function)
}
}
num_bytes_needed_from_ringbuf--;
}
app_p += appbuf_sample_size_in_bytes;
}
exit:
return num_bytes_copied_to_appbuf;
}
// function is used in IRQ context
STATIC void fill_appbuf_from_ringbuf_non_blocking(machine_i2s_obj_t *self) {
// attempt to copy a block of audio samples from the ring buffer to the supplied app buffer.
// audio samples will be formatted as part of the copy operation
uint32_t num_bytes_copied_to_appbuf = 0;
uint8_t *app_p = &(((uint8_t *)self->non_blocking_descriptor.appbuf.buf)[self->non_blocking_descriptor.index]);
uint8_t appbuf_sample_size_in_bytes = (self->bits == 16? 2 : 4) * (self->format == STEREO ? 2: 1);
uint32_t num_bytes_remaining_to_copy_to_appbuf = self->non_blocking_descriptor.appbuf.len - self->non_blocking_descriptor.index;
uint32_t num_bytes_remaining_to_copy_from_ring_buffer = num_bytes_remaining_to_copy_to_appbuf *
(I2S_RX_FRAME_SIZE_IN_BYTES / appbuf_sample_size_in_bytes);
uint32_t num_bytes_needed_from_ringbuf = MIN(SIZEOF_NON_BLOCKING_COPY_IN_BYTES, num_bytes_remaining_to_copy_from_ring_buffer);
uint8_t discard_byte;
if (ringbuf_available_data(&self->ring_buffer) >= num_bytes_needed_from_ringbuf) {
while (num_bytes_needed_from_ringbuf) {
uint8_t f_index = get_frame_mapping_index(self->bits, self->format);
for (uint8_t i = 0; i < I2S_RX_FRAME_SIZE_IN_BYTES; i++) {
int8_t r_to_a_mapping = i2s_frame_map[f_index][i];
if (r_to_a_mapping != -1) {
ringbuf_pop(&self->ring_buffer, app_p + r_to_a_mapping);
num_bytes_copied_to_appbuf++;
} else { // r_a_mapping == -1
// discard unused byte from ring buffer
ringbuf_pop(&self->ring_buffer, &discard_byte);
}
num_bytes_needed_from_ringbuf--;
}
app_p += appbuf_sample_size_in_bytes;
}
self->non_blocking_descriptor.index += num_bytes_copied_to_appbuf;
if (self->non_blocking_descriptor.index >= self->non_blocking_descriptor.appbuf.len) {
self->non_blocking_descriptor.copy_in_progress = false;
mp_sched_schedule(self->callback_for_non_blocking, MP_OBJ_FROM_PTR(self));
}
}
}
STATIC uint32_t copy_appbuf_to_ringbuf(machine_i2s_obj_t *self, mp_buffer_info_t *appbuf) {
// copy audio samples from the app buffer to the ring buffer
// loop, reading samples until the app buffer is emptied
// for uasyncio mode, the loop will make an early exit if the ring buffer becomes full
uint32_t a_index = 0;
while (a_index < appbuf->len) {
if (self->io_mode == BLOCKING) {
// copy a byte to the ringbuf when space becomes available
while (ringbuf_push(&self->ring_buffer, ((uint8_t *)appbuf->buf)[a_index]) == false) {
;
}
a_index++;
} else if (self->io_mode == UASYNCIO) {
if (ringbuf_push(&self->ring_buffer, ((uint8_t *)appbuf->buf)[a_index]) == false) {
// ring buffer is full, exit
break;
} else {
a_index++;
}
} else {
return 0; // should never get here (non-blocking mode does not use this function)
}
}
return a_index;
}
// function is used in IRQ context
STATIC void copy_appbuf_to_ringbuf_non_blocking(machine_i2s_obj_t *self) {
// copy audio samples from app buffer into ring buffer
uint32_t num_bytes_remaining_to_copy = self->non_blocking_descriptor.appbuf.len - self->non_blocking_descriptor.index;
uint32_t num_bytes_to_copy = MIN(SIZEOF_NON_BLOCKING_COPY_IN_BYTES, num_bytes_remaining_to_copy);
if (ringbuf_available_space(&self->ring_buffer) >= num_bytes_to_copy) {
for (uint32_t i = 0; i < num_bytes_to_copy; i++) {
ringbuf_push(&self->ring_buffer,
((uint8_t *)self->non_blocking_descriptor.appbuf.buf)[self->non_blocking_descriptor.index + i]);
}
self->non_blocking_descriptor.index += num_bytes_to_copy;
if (self->non_blocking_descriptor.index >= self->non_blocking_descriptor.appbuf.len) {
self->non_blocking_descriptor.copy_in_progress = false;
mp_sched_schedule(self->callback_for_non_blocking, MP_OBJ_FROM_PTR(self));
}
}
}
// function is used in IRQ context
STATIC void empty_dma(machine_i2s_obj_t *self, ping_pong_t dma_ping_pong) {
uint16_t dma_buffer_offset = 0;
if (dma_ping_pong == TOP_HALF) {
dma_buffer_offset = 0;
} else { // BOTTOM_HALF
dma_buffer_offset = SIZEOF_HALF_DMA_BUFFER_IN_BYTES;
}
uint8_t *dma_buffer_p = &self->dma_buffer_dcache_aligned[dma_buffer_offset];
// flush and invalidate cache so the CPU reads data placed into RAM by DMA
MP_HAL_CLEANINVALIDATE_DCACHE(dma_buffer_p, SIZEOF_HALF_DMA_BUFFER_IN_BYTES);
// when space exists, copy samples into ring buffer
if (ringbuf_available_space(&self->ring_buffer) >= SIZEOF_HALF_DMA_BUFFER_IN_BYTES) {
for (uint32_t i = 0; i < SIZEOF_HALF_DMA_BUFFER_IN_BYTES; i++) {
ringbuf_push(&self->ring_buffer, dma_buffer_p[i]);
}
}
}
// function is used in IRQ context
STATIC void feed_dma(machine_i2s_obj_t *self, ping_pong_t dma_ping_pong) {
uint16_t dma_buffer_offset = 0;
if (dma_ping_pong == TOP_HALF) {
dma_buffer_offset = 0;
} else { // BOTTOM_HALF
dma_buffer_offset = SIZEOF_HALF_DMA_BUFFER_IN_BYTES;
}
uint8_t *dma_buffer_p = &self->dma_buffer_dcache_aligned[dma_buffer_offset];
// when data exists, copy samples from ring buffer
if (ringbuf_available_data(&self->ring_buffer) >= SIZEOF_HALF_DMA_BUFFER_IN_BYTES) {
// copy a block of samples from the ring buffer to the dma buffer.
// mono format is implemented by duplicating each sample into both L and R channels.
if ((self->format == MONO) && (self->bits == 16)) {
for (uint32_t i = 0; i < SIZEOF_HALF_DMA_BUFFER_IN_BYTES / 4; i++) {
for (uint8_t b = 0; b < sizeof(uint16_t); b++) {
ringbuf_pop(&self->ring_buffer, &dma_buffer_p[i * 4 + b]);
dma_buffer_p[i * 4 + b + 2] = dma_buffer_p[i * 4 + b]; // duplicated mono sample
}
}
} else if ((self->format == MONO) && (self->bits == 32)) {
for (uint32_t i = 0; i < SIZEOF_HALF_DMA_BUFFER_IN_BYTES / 8; i++) {
for (uint8_t b = 0; b < sizeof(uint32_t); b++) {
ringbuf_pop(&self->ring_buffer, &dma_buffer_p[i * 8 + b]);
dma_buffer_p[i * 8 + b + 4] = dma_buffer_p[i * 8 + b]; // duplicated mono sample
}
}
} else { // STEREO, both 16-bit and 32-bit
for (uint32_t i = 0; i < SIZEOF_HALF_DMA_BUFFER_IN_BYTES; i++) {
ringbuf_pop(&self->ring_buffer, &dma_buffer_p[i]);
}
}
} else {
// underflow. clear buffer to transmit "silence" on the I2S bus
memset(dma_buffer_p, 0, SIZEOF_HALF_DMA_BUFFER_IN_BYTES);
}
// flush cache to RAM so DMA can read the sample data
MP_HAL_CLEAN_DCACHE(dma_buffer_p, SIZEOF_HALF_DMA_BUFFER_IN_BYTES);
}
STATIC void edma_i2s_callback(edma_handle_t *handle, void *userData, bool transferDone, uint32_t tcds) {
machine_i2s_obj_t *self = userData;
if (self->mode == TX) {
// for non-blocking mode, sample copying (appbuf->ibuf) is initiated in this callback routine
if ((self->io_mode == NON_BLOCKING) && (self->non_blocking_descriptor.copy_in_progress)) {
copy_appbuf_to_ringbuf_non_blocking(self);
}
if (transferDone) {
// bottom half of buffer now emptied,
// safe to fill the bottom half while the top half of buffer is being emptied
feed_dma(self, BOTTOM_HALF);
} else {
// top half of buffer now emptied,
// safe to fill the top half while the bottom half of buffer is being emptied
feed_dma(self, TOP_HALF);
}
} else { // RX
if (transferDone) {
// bottom half of buffer now filled,
// safe to empty the bottom half while the top half of buffer is being filled
empty_dma(self, BOTTOM_HALF);
} else {
// top half of buffer now filled,
// safe to empty the top half while the bottom half of buffer is being filled
empty_dma(self, TOP_HALF);
}
// for non-blocking mode, sample copying (ibuf->appbuf) is initiated in this callback routine
if ((self->io_mode == NON_BLOCKING) && (self->non_blocking_descriptor.copy_in_progress)) {
fill_appbuf_from_ringbuf_non_blocking(self);
}
}
}
STATIC bool i2s_init(machine_i2s_obj_t *self) {
CLOCK_InitAudioPll(get_pll_config(self->rate));
CLOCK_SetMux(i2s_clock_mux[self->i2s_id], AUDIO_PLL_CLOCK);
CLOCK_SetDiv(i2s_clock_pre_div[self->i2s_id], get_clock_pre_divider(self->rate));
CLOCK_SetDiv(i2s_clock_div[self->i2s_id], get_clock_divider(self->rate));
if (!set_iomux(self->sck, SCK, self->i2s_id)) {
return false;
}
if (!set_iomux(self->ws, WS, self->i2s_id)) {
return false;
}
if (!set_iomux(self->sd, SD, self->i2s_id)) {
return false;
}
if (self->mck) {
if (!set_iomux(self->mck, MCK, self->i2s_id)) {
return false;
}
IOMUXC_EnableMode(IOMUXC_GPR, i2s_iomuxc_gpr_mode[self->i2s_id], true);
}
self->dma_channel = allocate_dma_channel();
DMAMUX_Init(DMAMUX);
if (self->mode == TX) {
DMAMUX_SetSource(DMAMUX, self->dma_channel, i2s_dma_req_src_tx[self->i2s_id]);
} else { // RX
DMAMUX_SetSource(DMAMUX, self->dma_channel, i2s_dma_req_src_rx[self->i2s_id]);
}
DMAMUX_EnableChannel(DMAMUX, self->dma_channel);
dma_init();
EDMA_CreateHandle(&self->edmaHandle, DMA0, self->dma_channel);
EDMA_SetCallback(&self->edmaHandle, edma_i2s_callback, self);
EDMA_ResetChannel(DMA0, self->dma_channel);
SAI_Init(self->i2s_inst);
sai_transceiver_t saiConfig;
SAI_GetClassicI2SConfig(&saiConfig, get_dma_bits(self->mode, self->bits), kSAI_Stereo, kSAI_Channel0Mask);
saiConfig.masterSlave = kSAI_Master;
uint16_t sck_index;
lookup_gpio(self->sck, SCK, self->i2s_id, &sck_index);
if ((self->mode == TX) && (i2s_gpio_map[sck_index].mode == TX)) {
saiConfig.syncMode = kSAI_ModeAsync;
SAI_TxSetConfig(self->i2s_inst, &saiConfig);
} else if ((self->mode == RX) && (i2s_gpio_map[sck_index].mode == RX)) {
saiConfig.syncMode = kSAI_ModeAsync;
SAI_RxSetConfig(self->i2s_inst, &saiConfig);
} else if ((self->mode == TX) && (i2s_gpio_map[sck_index].mode == RX)) {
saiConfig.syncMode = kSAI_ModeAsync;
SAI_RxSetConfig(self->i2s_inst, &saiConfig);
saiConfig.bitClock.bclkSrcSwap = true;
saiConfig.syncMode = kSAI_ModeSync;
SAI_TxSetConfig(self->i2s_inst, &saiConfig);
} else if ((self->mode == RX) && (i2s_gpio_map[sck_index].mode == TX)) {
saiConfig.syncMode = kSAI_ModeAsync;
SAI_TxSetConfig(self->i2s_inst, &saiConfig);
saiConfig.syncMode = kSAI_ModeSync;
SAI_RxSetConfig(self->i2s_inst, &saiConfig);
} else {
return false; // should never happen
}
uint32_t clock_freq =
(CLOCK_GetFreq(kCLOCK_AudioPllClk) / (get_clock_divider(self->rate) + 1U) /
(get_clock_pre_divider(self->rate) + 1U));
SAI_TxSetBitClockRate(self->i2s_inst, clock_freq, self->rate, get_dma_bits(self->mode, self->bits),
SAI_NUM_AUDIO_CHANNELS);
SAI_RxSetBitClockRate(self->i2s_inst, clock_freq, self->rate, get_dma_bits(self->mode, self->bits),
SAI_NUM_AUDIO_CHANNELS);
edma_transfer_config_t transferConfig;
uint8_t bytes_per_sample = get_dma_bits(self->mode, self->bits) / 8;
if (self->mode == TX) {
uint32_t destAddr = SAI_TxGetDataRegisterAddress(self->i2s_inst, SAI_CHANNEL_0);
EDMA_PrepareTransfer(&transferConfig,
self->dma_buffer_dcache_aligned, bytes_per_sample,
(void *)destAddr, bytes_per_sample,
(FSL_FEATURE_SAI_FIFO_COUNT - saiConfig.fifo.fifoWatermark) * bytes_per_sample,
SIZEOF_DMA_BUFFER_IN_BYTES, kEDMA_MemoryToPeripheral);
} else { // RX
uint32_t srcAddr = SAI_RxGetDataRegisterAddress(self->i2s_inst, SAI_CHANNEL_0);
EDMA_PrepareTransfer(&transferConfig,
(void *)srcAddr, bytes_per_sample,
self->dma_buffer_dcache_aligned, bytes_per_sample,
(FSL_FEATURE_SAI_FIFO_COUNT - saiConfig.fifo.fifoWatermark) * bytes_per_sample,
SIZEOF_DMA_BUFFER_IN_BYTES, kEDMA_PeripheralToMemory);
}
memset(self->edmaTcd, 0, sizeof(edma_tcd_t));
// continuous DMA operation is acheived using the scatter/gather feature, with one TCD linked back to itself
EDMA_TcdSetTransferConfig(self->edmaTcd, &transferConfig, self->edmaTcd);
EDMA_TcdEnableInterrupts(self->edmaTcd, kEDMA_MajorInterruptEnable | kEDMA_HalfInterruptEnable);
EDMA_InstallTCD(DMA0, self->dma_channel, self->edmaTcd);
EDMA_StartTransfer(&self->edmaHandle);
if (self->mode == TX) {
SAI_TxEnableDMA(self->i2s_inst, kSAI_FIFORequestDMAEnable, true);
SAI_TxEnable(self->i2s_inst, true);
SAI_TxSetChannelFIFOMask(self->i2s_inst, kSAI_Channel0Mask);
} else { // RX
SAI_RxEnableDMA(self->i2s_inst, kSAI_FIFORequestDMAEnable, true);
SAI_RxEnable(self->i2s_inst, true);
SAI_RxSetChannelFIFOMask(self->i2s_inst, kSAI_Channel0Mask);
}
return true;
}
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_mck,
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_mck, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = mp_const_none} },
{ 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 ----
//
// is Mode valid?
uint16_t i2s_mode = args[ARG_mode].u_int;
if ((i2s_mode != (RX)) &&
(i2s_mode != (TX))) {
mp_raise_ValueError(MP_ERROR_TEXT("invalid mode"));
}
// are I2S pin assignments valid?
uint16_t not_used;
// is SCK valid?
const machine_pin_obj_t *pin_sck = pin_find(args[ARG_sck].u_obj);
if (!lookup_gpio(pin_sck, SCK, self->i2s_id, &not_used)) {
mp_raise_ValueError(MP_ERROR_TEXT("invalid SCK pin"));
}
// is WS valid?
const machine_pin_obj_t *pin_ws = pin_find(args[ARG_ws].u_obj);
if (!lookup_gpio(pin_ws, WS, self->i2s_id, &not_used)) {
mp_raise_ValueError(MP_ERROR_TEXT("invalid WS pin"));
}
// is SD valid?
const machine_pin_obj_t *pin_sd = pin_find(args[ARG_sd].u_obj);
uint16_t mapping_index;
bool invalid_sd = true;
if (lookup_gpio(pin_sd, SD, self->i2s_id, &mapping_index)) {
if (i2s_mode == i2s_gpio_map[mapping_index].mode) {
invalid_sd = false;
}
}
if (invalid_sd) {
mp_raise_ValueError(MP_ERROR_TEXT("invalid SD pin"));
}
// is MCK defined and valid?
const machine_pin_obj_t *pin_mck = NULL;
if (args[ARG_mck].u_obj != mp_const_none) {
pin_mck = pin_find(args[ARG_mck].u_obj);
if (!lookup_gpio(pin_mck, MCK, self->i2s_id, &not_used)) {
mp_raise_ValueError(MP_ERROR_TEXT("invalid MCK pin"));
}
}
// is Bits valid?
int8_t i2s_bits = args[ARG_bits].u_int;
if ((i2s_bits != 16) &&
(i2s_bits != 32)) {
mp_raise_ValueError(MP_ERROR_TEXT("invalid bits"));
}
// is Format valid?
format_t i2s_format = args[ARG_format].u_int;
if ((i2s_format != MONO) &&
(i2s_format != STEREO)) {
mp_raise_ValueError(MP_ERROR_TEXT("invalid format"));
}
// is Rate valid?
int32_t i2s_rate = args[ARG_rate].u_int;
if (!is_rate_supported(i2s_rate)) {
mp_raise_ValueError(MP_ERROR_TEXT("invalid rate"));
}
// is Ibuf valid?
int32_t ring_buffer_len = args[ARG_ibuf].u_int;
if (ring_buffer_len > 0) {
uint8_t *buffer = m_new(uint8_t, ring_buffer_len);
self->ring_buffer_storage = buffer;
ringbuf_init(&self->ring_buffer, buffer, ring_buffer_len);
} else {
mp_raise_ValueError(MP_ERROR_TEXT("invalid ibuf"));
}
self->sck = pin_sck;
self->ws = pin_ws;
self->sd = pin_sd;
self->mck = pin_mck;
self->mode = i2s_mode;
self->bits = i2s_bits;
self->format = i2s_format;
self->rate = i2s_rate;
self->ibuf = ring_buffer_len;
self->callback_for_non_blocking = MP_OBJ_NULL;
self->non_blocking_descriptor.copy_in_progress = false;
self->io_mode = BLOCKING;
self->i2s_inst = (I2S_Type *)i2s_base_ptr[self->i2s_id];
// init the I2S bus
if (!i2s_init(self)) {
mp_raise_msg_varg(&mp_type_OSError, MP_ERROR_TEXT("I2S init failed"));
}
}
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"
"mck="MP_HAL_PIN_FMT ",\n"
"mode=%u,\n"
"bits=%u, format=%u,\n"
"rate=%d, ibuf=%d)",
self->i2s_id,
mp_hal_pin_name(self->sck),
mp_hal_pin_name(self->ws),
mp_hal_pin_name(self->sd),
mp_hal_pin_name(self->mck),
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);
uint8_t i2s_id = mp_obj_get_int(args[0]);
if (i2s_id < 1 || i2s_id > MICROPY_HW_I2S_NUM) {
mp_raise_msg_varg(&mp_type_ValueError, MP_ERROR_TEXT("I2S(%d) does not exist"), i2s_id);
}
uint8_t i2s_id_zero_base = i2s_id - 1;
machine_i2s_obj_t *self;
if (MP_STATE_PORT(machine_i2s_obj)[i2s_id_zero_base] == NULL) {
self = mp_obj_malloc(machine_i2s_obj_t, &machine_i2s_type);
MP_STATE_PORT(machine_i2s_obj)[i2s_id_zero_base] = self;
self->i2s_id = i2s_id;
self->edmaTcd = &edmaTcd[i2s_id_zero_base];
} else {
self = MP_STATE_PORT(machine_i2s_obj)[i2s_id_zero_base];
machine_i2s_deinit(MP_OBJ_FROM_PTR(self));
}
// align DMA buffer to the cache line size (32 bytes)
self->dma_buffer_dcache_aligned = (uint8_t *)((uint32_t)(self->dma_buffer + 0x1f) & ~0x1f);
// fill the DMA buffer with NULLs
memset(self->dma_buffer_dcache_aligned, 0, SIZEOF_DMA_BUFFER_IN_BYTES);
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_init(size_t n_pos_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
machine_i2s_obj_t *self = MP_OBJ_TO_PTR(pos_args[0]);
machine_i2s_deinit(MP_OBJ_FROM_PTR(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_init);
STATIC mp_obj_t machine_i2s_deinit(mp_obj_t self_in) {
machine_i2s_obj_t *self = MP_OBJ_TO_PTR(self_in);
// use self->i2s_inst as in indication that I2S object has already been de-initialized
if (self->i2s_inst != NULL) {
EDMA_AbortTransfer(&self->edmaHandle);
if (self->mode == TX) {
SAI_TxSetChannelFIFOMask(self->i2s_inst, 0);
SAI_TxEnableDMA(self->i2s_inst, kSAI_FIFORequestDMAEnable, false);
SAI_TxEnable(self->i2s_inst, false);
SAI_TxReset(self->i2s_inst);
} else { // RX
SAI_RxSetChannelFIFOMask(self->i2s_inst, 0);
SAI_RxEnableDMA(self->i2s_inst, kSAI_FIFORequestDMAEnable, false);
SAI_RxEnable(self->i2s_inst, false);
SAI_RxReset(self->i2s_inst);
}
SAI_Deinit(self->i2s_inst);
free_dma_channel(self->dma_channel);
m_free(self->ring_buffer_storage);
self->i2s_inst = NULL; // flag object as de-initialized
}
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;
} else {
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_OBJ_NULL} },
{ 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 / sizeof(uint16_t);
break;
case 32:
num_audio_samples = bufinfo.len / sizeof(uint32_t);
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(RX) },
{ MP_ROM_QSTR(MP_QSTR_TX), MP_ROM_INT(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 != 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) {
self->non_blocking_descriptor.appbuf.buf = (void *)buf_in;
self->non_blocking_descriptor.appbuf.len = size;
self->non_blocking_descriptor.index = 0;
self->non_blocking_descriptor.copy_in_progress = true;
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_ringbuf(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 != TX) {
*errcode = MP_EPERM;
return MP_STREAM_ERROR;
}
if (size == 0) {
return 0;
}
if (self->io_mode == NON_BLOCKING) {
self->non_blocking_descriptor.appbuf.buf = (void *)buf_in;
self->non_blocking_descriptor.appbuf.len = size;
self->non_blocking_descriptor.index = 0;
self->non_blocking_descriptor.copy_in_progress = true;
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_ringbuf(self, &appbuf);
return num_bytes_written;
}
}
STATIC mp_uint_t machine_i2s_ioctl(mp_obj_t self_in, mp_uint_t request, uintptr_t arg, int *errcode) {
machine_i2s_obj_t *self = MP_OBJ_TO_PTR(self_in);
mp_uint_t ret;
uintptr_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 != RX) {
*errcode = MP_EPERM;
return MP_STREAM_ERROR;
}
if (!ringbuf_is_empty(&self->ring_buffer)) {
ret |= MP_STREAM_POLL_RD;
}
}
if (flags & MP_STREAM_POLL_WR) {
if (self->mode != TX) {
*errcode = MP_EPERM;
return MP_STREAM_ERROR;
}
if (!ringbuf_is_full(&self->ring_buffer)) {
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,
};
MP_DEFINE_CONST_OBJ_TYPE(
machine_i2s_type,
MP_QSTR_I2S,
MP_TYPE_FLAG_ITER_IS_STREAM,
make_new, machine_i2s_make_new,
print, machine_i2s_print,
protocol, &i2s_stream_p,
locals_dict, &machine_i2s_locals_dict
);
MP_REGISTER_ROOT_POINTER(struct _machine_i2s_obj_t *machine_i2s_obj[MICROPY_HW_I2S_NUM]);
#endif // MICROPY_PY_MACHINE_I2S
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