esp-idf/components/driver/rmt/rmt_encoder.c

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/*
* SPDX-FileCopyrightText: 2022-2024 Espressif Systems (Shanghai) CO LTD
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <stdlib.h>
#include <string.h>
#include <sys/cdefs.h>
#include <sys/param.h>
#include "sdkconfig.h"
#if CONFIG_RMT_ENABLE_DEBUG_LOG
// The local log level must be defined before including esp_log.h
// Set the maximum log level for this source file
#define LOG_LOCAL_LEVEL ESP_LOG_DEBUG
#endif
#include "esp_log.h"
#include "esp_check.h"
#include "driver/rmt_encoder.h"
#include "rmt_private.h"
static const char *TAG = "rmt";
typedef struct rmt_bytes_encoder_t {
rmt_encoder_t base; // encoder base class
size_t last_bit_index; // index of the encoding bit position in the encoding byte
size_t last_byte_index; // index of the encoding byte in the primary stream
rmt_symbol_word_t bit0; // bit zero representing
rmt_symbol_word_t bit1; // bit one representing
struct {
uint32_t msb_first: 1; // encode MSB firstly
} flags;
} rmt_bytes_encoder_t;
typedef struct rmt_copy_encoder_t {
rmt_encoder_t base; // encoder base class
size_t last_symbol_index; // index of symbol position in the primary stream
} rmt_copy_encoder_t;
static esp_err_t rmt_bytes_encoder_reset(rmt_encoder_t *encoder)
{
rmt_bytes_encoder_t *bytes_encoder = __containerof(encoder, rmt_bytes_encoder_t, base);
// reset index to zero
bytes_encoder->last_bit_index = 0;
bytes_encoder->last_byte_index = 0;
return ESP_OK;
}
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__attribute__((always_inline))
static inline uint8_t _bitwise_reverse(uint8_t n)
{
n = ((n & 0xf0) >> 4) | ((n & 0x0f) << 4);
n = ((n & 0xcc) >> 2) | ((n & 0x33) << 2);
n = ((n & 0xaa) >> 1) | ((n & 0x55) << 1);
return n;
}
static size_t IRAM_ATTR rmt_encode_bytes(rmt_encoder_t *encoder, rmt_channel_handle_t channel,
const void *primary_data, size_t data_size, rmt_encode_state_t *ret_state)
{
rmt_bytes_encoder_t *bytes_encoder = __containerof(encoder, rmt_bytes_encoder_t, base);
rmt_tx_channel_t *tx_chan = __containerof(channel, rmt_tx_channel_t, base);
const uint8_t *nd = (const uint8_t *)primary_data;
rmt_encode_state_t state = RMT_ENCODING_RESET;
dma_descriptor_t *desc0 = NULL;
dma_descriptor_t *desc1 = NULL;
size_t byte_index = bytes_encoder->last_byte_index;
size_t bit_index = bytes_encoder->last_bit_index;
// how many symbols will be generated by the encoder
size_t mem_want = (data_size - byte_index - 1) * 8 + (8 - bit_index);
// how many symbols we can save for this round
size_t mem_have = tx_chan->mem_end - tx_chan->mem_off;
// where to put the encoded symbols? DMA buffer or RMT HW memory
rmt_symbol_word_t *mem_to = channel->dma_chan ? channel->dma_mem_base : channel->hw_mem_base;
// how many symbols will be encoded in this round
size_t encode_len = MIN(mem_want, mem_have);
bool encoding_truncated = mem_have < mem_want;
bool encoding_space_free = mem_have > mem_want;
if (channel->dma_chan) {
// mark the start descriptor
if (tx_chan->mem_off < tx_chan->ping_pong_symbols) {
desc0 = &tx_chan->dma_nodes[0];
} else {
desc0 = &tx_chan->dma_nodes[1];
}
}
size_t len = encode_len;
while (len > 0) {
// start from last time truncated encoding
uint8_t cur_byte = nd[byte_index];
// bit-wise reverse
if (bytes_encoder->flags.msb_first) {
cur_byte = _bitwise_reverse(cur_byte);
}
while ((len > 0) && (bit_index < 8)) {
if (cur_byte & (1 << bit_index)) {
mem_to[tx_chan->mem_off++] = bytes_encoder->bit1;
} else {
mem_to[tx_chan->mem_off++] = bytes_encoder->bit0;
}
len--;
bit_index++;
}
if (bit_index >= 8) {
byte_index++;
bit_index = 0;
}
}
if (channel->dma_chan) {
// mark the end descriptor
if (tx_chan->mem_off < tx_chan->ping_pong_symbols) {
desc1 = &tx_chan->dma_nodes[0];
} else {
desc1 = &tx_chan->dma_nodes[1];
}
// cross line, means desc0 has prepared with sufficient data buffer
if (desc0 != desc1) {
desc0->dw0.length = tx_chan->ping_pong_symbols * sizeof(rmt_symbol_word_t);
desc0->dw0.owner = DMA_DESCRIPTOR_BUFFER_OWNER_DMA;
}
}
if (encoding_truncated) {
// this encoding has not finished yet, save the truncated position
bytes_encoder->last_bit_index = bit_index;
bytes_encoder->last_byte_index = byte_index;
} else {
// reset internal index if encoding session has finished
bytes_encoder->last_bit_index = 0;
bytes_encoder->last_byte_index = 0;
state |= RMT_ENCODING_COMPLETE;
}
if (!encoding_space_free) {
// no more free memory, the caller should yield
state |= RMT_ENCODING_MEM_FULL;
}
// reset offset pointer when exceeds maximum range
if (tx_chan->mem_off >= tx_chan->ping_pong_symbols * 2) {
if (channel->dma_chan) {
desc1->dw0.length = tx_chan->ping_pong_symbols * sizeof(rmt_symbol_word_t);
desc1->dw0.owner = DMA_DESCRIPTOR_BUFFER_OWNER_DMA;
}
tx_chan->mem_off = 0;
}
*ret_state = state;
return encode_len;
}
static esp_err_t rmt_copy_encoder_reset(rmt_encoder_t *encoder)
{
rmt_copy_encoder_t *copy_encoder = __containerof(encoder, rmt_copy_encoder_t, base);
copy_encoder->last_symbol_index = 0;
return ESP_OK;
}
static size_t IRAM_ATTR rmt_encode_copy(rmt_encoder_t *encoder, rmt_channel_handle_t channel,
const void *primary_data, size_t data_size, rmt_encode_state_t *ret_state)
{
rmt_copy_encoder_t *copy_encoder = __containerof(encoder, rmt_copy_encoder_t, base);
rmt_tx_channel_t *tx_chan = __containerof(channel, rmt_tx_channel_t, base);
rmt_symbol_word_t *symbols = (rmt_symbol_word_t *)primary_data;
rmt_encode_state_t state = RMT_ENCODING_RESET;
dma_descriptor_t *desc0 = NULL;
dma_descriptor_t *desc1 = NULL;
size_t symbol_index = copy_encoder->last_symbol_index;
// how many symbols will be copied by the encoder
size_t mem_want = (data_size / 4 - symbol_index);
// how many symbols we can save for this round
size_t mem_have = tx_chan->mem_end - tx_chan->mem_off;
// where to put the encoded symbols? DMA buffer or RMT HW memory
rmt_symbol_word_t *mem_to = channel->dma_chan ? channel->dma_mem_base : channel->hw_mem_base;
// how many symbols will be encoded in this round
size_t encode_len = MIN(mem_want, mem_have);
bool encoding_truncated = mem_have < mem_want;
bool encoding_space_free = mem_have > mem_want;
if (channel->dma_chan) {
// mark the start descriptor
if (tx_chan->mem_off < tx_chan->ping_pong_symbols) {
desc0 = &tx_chan->dma_nodes[0];
} else {
desc0 = &tx_chan->dma_nodes[1];
}
}
size_t len = encode_len;
while (len > 0) {
mem_to[tx_chan->mem_off++] = symbols[symbol_index++];
len--;
}
if (channel->dma_chan) {
// mark the end descriptor
if (tx_chan->mem_off < tx_chan->ping_pong_symbols) {
desc1 = &tx_chan->dma_nodes[0];
} else {
desc1 = &tx_chan->dma_nodes[1];
}
// cross line, means desc0 has prepared with sufficient data buffer
if (desc0 != desc1) {
desc0->dw0.length = tx_chan->ping_pong_symbols * sizeof(rmt_symbol_word_t);
desc0->dw0.owner = DMA_DESCRIPTOR_BUFFER_OWNER_DMA;
}
}
if (encoding_truncated) {
// this encoding has not finished yet, save the truncated position
copy_encoder->last_symbol_index = symbol_index;
} else {
// reset internal index if encoding session has finished
copy_encoder->last_symbol_index = 0;
state |= RMT_ENCODING_COMPLETE;
}
if (!encoding_space_free) {
// no more free memory, the caller should yield
state |= RMT_ENCODING_MEM_FULL;
}
// reset offset pointer when exceeds maximum range
if (tx_chan->mem_off >= tx_chan->ping_pong_symbols * 2) {
if (channel->dma_chan) {
desc1->dw0.length = tx_chan->ping_pong_symbols * sizeof(rmt_symbol_word_t);
desc1->dw0.owner = DMA_DESCRIPTOR_BUFFER_OWNER_DMA;
}
tx_chan->mem_off = 0;
}
*ret_state = state;
return encode_len;
}
static esp_err_t rmt_del_bytes_encoder(rmt_encoder_t *encoder)
{
rmt_bytes_encoder_t *bytes_encoder = __containerof(encoder, rmt_bytes_encoder_t, base);
free(bytes_encoder);
return ESP_OK;
}
static esp_err_t rmt_del_copy_encoder(rmt_encoder_t *encoder)
{
rmt_copy_encoder_t *copy_encoder = __containerof(encoder, rmt_copy_encoder_t, base);
free(copy_encoder);
return ESP_OK;
}
esp_err_t rmt_new_bytes_encoder(const rmt_bytes_encoder_config_t *config, rmt_encoder_handle_t *ret_encoder)
{
esp_err_t ret = ESP_OK;
ESP_GOTO_ON_FALSE(config && ret_encoder, ESP_ERR_INVALID_ARG, err, TAG, "invalid argument");
rmt_bytes_encoder_t *encoder = rmt_alloc_encoder_mem(sizeof(rmt_bytes_encoder_t));
ESP_GOTO_ON_FALSE(encoder, ESP_ERR_NO_MEM, err, TAG, "no mem for bytes encoder");
encoder->base.encode = rmt_encode_bytes;
encoder->base.del = rmt_del_bytes_encoder;
encoder->base.reset = rmt_bytes_encoder_reset;
encoder->bit0 = config->bit0;
encoder->bit1 = config->bit1;
encoder->flags.msb_first = config->flags.msb_first;
// return general encoder handle
*ret_encoder = &encoder->base;
ESP_LOGD(TAG, "new bytes encoder @%p", encoder);
err:
return ret;
}
esp_err_t rmt_bytes_encoder_update_config(rmt_encoder_handle_t bytes_encoder, const rmt_bytes_encoder_config_t *config)
{
ESP_RETURN_ON_FALSE(bytes_encoder && config, ESP_ERR_INVALID_ARG, TAG, "invalid argument");
rmt_bytes_encoder_t *encoder = __containerof(bytes_encoder, rmt_bytes_encoder_t, base);
encoder->bit0 = config->bit0;
encoder->bit1 = config->bit1;
encoder->flags.msb_first = config->flags.msb_first;
return ESP_OK;
}
esp_err_t rmt_new_copy_encoder(const rmt_copy_encoder_config_t *config, rmt_encoder_handle_t *ret_encoder)
{
esp_err_t ret = ESP_OK;
ESP_GOTO_ON_FALSE(config && ret_encoder, ESP_ERR_INVALID_ARG, err, TAG, "invalid argument");
rmt_copy_encoder_t *encoder = rmt_alloc_encoder_mem(sizeof(rmt_copy_encoder_t));
ESP_GOTO_ON_FALSE(encoder, ESP_ERR_NO_MEM, err, TAG, "no mem for copy encoder");
encoder->base.encode = rmt_encode_copy;
encoder->base.del = rmt_del_copy_encoder;
encoder->base.reset = rmt_copy_encoder_reset;
// return general encoder handle
*ret_encoder = &encoder->base;
ESP_LOGD(TAG, "new copy encoder @%p", encoder);
err:
return ret;
}
esp_err_t rmt_del_encoder(rmt_encoder_handle_t encoder)
{
ESP_RETURN_ON_FALSE(encoder, ESP_ERR_INVALID_ARG, TAG, "invalid argument");
return encoder->del(encoder);
}
esp_err_t rmt_encoder_reset(rmt_encoder_handle_t encoder)
{
ESP_RETURN_ON_FALSE(encoder, ESP_ERR_INVALID_ARG, TAG, "invalid argument");
return encoder->reset(encoder);
}
void* rmt_alloc_encoder_mem(size_t size)
{
return heap_caps_calloc(1, size, RMT_MEM_ALLOC_CAPS);
}