ESP32-PaxCounter/src/spislave.cpp

/*

//////////////////////// ESP32-Paxcounter \\\\\\\\\\\\\\\\\\\\\\\\\\

Copyright  2018 Christian Ambach <christian.ambach@deutschebahn.com>

   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.

NOTICE:
Parts of the source files in this repository are made available under different
licenses. Refer to LICENSE.txt file in repository for more details.

*/

#include "spislave.h"

#include <driver/spi_slave.h>
#include <sys/param.h>
#include <rom/crc.h>

static const char TAG[] = __FILE__;

#define HEADER_SIZE 4
// SPI transaction size needs to be at least 8 bytes and dividable by 4, see
// https://docs.espressif.com/projects/esp-idf/en/latest/api-reference/peripherals/spi_slave.html
#define BUFFER_SIZE                                                            \
  (MAX(8, HEADER_SIZE + PAYLOAD_BUFFER_SIZE) +                                 \
   (4 - MAX(8, HEADER_SIZE + PAYLOAD_BUFFER_SIZE) % 4))
DMA_ATTR uint8_t txbuf[BUFFER_SIZE];
DMA_ATTR uint8_t rxbuf[BUFFER_SIZE];

QueueHandle_t SPISendQueue;

TaskHandle_t spiTask;

void spi_slave_task(void *param) {
  while (1) {
    MessageBuffer_t msg;
    size_t transaction_size;

    // clear rx + tx buffers
    memset(txbuf, 0, sizeof(txbuf));
    memset(rxbuf, 0, sizeof(rxbuf));

    // wait until data to send arrivey
    if (xQueueReceive(SPISendQueue, &msg, portMAX_DELAY) != pdTRUE) {
      ESP_LOGE(TAG, "Premature return from xQueueReceive() with no data!");
      continue;
    }

    // fill tx buffer with data to send from queue and calculate crc16 cheksum
    uint8_t *messageType = txbuf + 2;
    *messageType = msg.MessagePort;
    uint8_t *messageSize = txbuf + 3;
    *messageSize = msg.MessageSize;
    memcpy(txbuf + HEADER_SIZE, &msg.Message, msg.MessageSize);
    // calculate crc16 checksum, not used yet
    // uint16_t *crc = (uint16_t *)txbuf;
    //*crc = crc16_be(0, messageType, msg.MessageSize + HEADER_SIZE - 2);

    // set length for spi slave driver
    transaction_size = HEADER_SIZE + msg.MessageSize;
    transaction_size += (4 - transaction_size % 4);

    // prepare spi transaction
    spi_slave_transaction_t spi_transaction = {0};
    spi_transaction.length = transaction_size * 8;
    spi_transaction.tx_buffer = txbuf;
    spi_transaction.rx_buffer = rxbuf;

    // wait until spi master clocks out the data, and read results in rx buffer
    ESP_LOGI(TAG, "Prepared SPI transaction for %zu bytes", transaction_size);
    ESP_LOG_BUFFER_HEXDUMP(TAG, txbuf, transaction_size, ESP_LOG_DEBUG);
    esp_err_t ret =
        spi_slave_transmit(HSPI_HOST, &spi_transaction, portMAX_DELAY);
    ESP_LOG_BUFFER_HEXDUMP(TAG, rxbuf, transaction_size, ESP_LOG_DEBUG);
    ESP_LOGI(TAG, "Transaction finished with size %zu bits",
             spi_transaction.trans_len);

    // check if command was received, then call interpreter with command payload
    if ((spi_transaction.trans_len) && ((rxbuf[2]) == RCMDPORT)) {
      rcommand(rxbuf + HEADER_SIZE, spi_transaction.trans_len - HEADER_SIZE);
    };
  }
}

esp_err_t spi_init() {
#ifndef HAS_SPI
  return ESP_OK;
#else

  SPISendQueue = xQueueCreate(SEND_QUEUE_SIZE, sizeof(MessageBuffer_t));
  if (SPISendQueue == 0) {
    ESP_LOGE(TAG, "Could not create SPI send queue. Aborting.");
    return ESP_FAIL;
  }
  ESP_LOGI(TAG, "SPI send queue created, size %d Bytes",
           SEND_QUEUE_SIZE * PAYLOAD_BUFFER_SIZE);

  spi_bus_config_t spi_bus_cfg = {.mosi_io_num = SPI_MOSI,
                                  .miso_io_num = SPI_MISO,
                                  .sclk_io_num = SPI_SCLK,
                                  .quadwp_io_num = -1,
                                  .quadhd_io_num = -1,
                                  .max_transfer_sz = 0,
                                  .flags = 0};

  spi_slave_interface_config_t spi_slv_cfg = {.spics_io_num = SPI_CS,
                                              .flags = 0,
                                              .queue_size = 1,
                                              .mode = 0,
                                              .post_setup_cb = NULL,
                                              .post_trans_cb = NULL};

  // Enable pull-ups on SPI lines so we don't detect rogue pulses when no master
  // is connected
  gpio_set_pull_mode(SPI_MOSI, GPIO_PULLUP_ONLY);
  gpio_set_pull_mode(SPI_SCLK, GPIO_PULLUP_ONLY);
  gpio_set_pull_mode(SPI_CS, GPIO_PULLUP_ONLY);

  esp_err_t ret =
      spi_slave_initialize(HSPI_HOST, &spi_bus_cfg, &spi_slv_cfg, 1);

  if (ret == ESP_OK) {
    ESP_LOGI(TAG, "Starting SPIloop...");
    xTaskCreate(spi_slave_task, "spiloop", 4096, (void *)NULL, 2, &spiTask);
  } else {
    ESP_LOGE(TAG, "SPI interface initialization failed");
  }

  return ret;

#endif
}

void spi_enqueuedata(uint8_t messageType, MessageBuffer_t *message) {
  // enqueue message in SPI send queue
#ifdef HAS_SPI
  BaseType_t ret =
      xQueueSendToBack(SPISendQueue, (void *)message, (TickType_t)0);
  if (ret == pdTRUE) {
    ESP_LOGI(TAG, "%d bytes enqueued for SPI interface", message->MessageSize);
  } else {
    ESP_LOGW(TAG, "SPI sendqueue is full");
  }
#endif
}

void spi_queuereset(void) {
#ifdef HAS_SPI
  xQueueReset(SPISendQueue);
#endif
}

void spi_housekeeping(void) {
#ifdef HAS_SPI
  ESP_LOGD(TAG, "spiloop %d bytes left", uxTaskGetStackHighWaterMark(spiTask));
#endif
}