LibrePilot/flight/pios/stm32f10x/pios_adc.c

/**
 ******************************************************************************
 * @addtogroup PIOS PIOS Core hardware abstraction layer
 * @{
 * @addtogroup   PIOS_ADC ADC Functions
 * @brief STM32 ADC PIOS interface
 * @{
 *
 * @file       pios_adc.c
 * @author     The OpenPilot Team, http://www.openpilot.org Copyright (C) 2012.
 * @brief      Analog to Digital converstion routines
 * @see        The GNU Public License (GPL) Version 3
 *****************************************************************************/
/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
 * for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include "pios.h"

#ifdef PIOS_INCLUDE_ADC

#include <pios_adc_priv.h>
// Private types

enum pios_adc_dev_magic {
    PIOS_ADC_DEV_MAGIC = 0x58375124,
};

struct pios_adc_dev {
    const struct pios_adc_cfg *cfg;
    ADCCallback      callback_function;
#if defined(PIOS_INCLUDE_FREERTOS)
    xQueueHandle     data_queue;
#endif
    volatile int16_t *valid_data_buffer;
    volatile uint8_t adc_oversample;
    volatile uint8_t adc_oversample_block_size;
    uint8_t  dma_block_size;
    uint16_t dma_half_buffer_size;
#if defined(PIOS_INCLUDE_ADC)
    int16_t  fir_coeffs[PIOS_ADC_MAX_SAMPLES + 1]  __attribute__((aligned(4)));
    volatile int16_t raw_data_buffer[PIOS_ADC_MAX_SAMPLES]  __attribute__((aligned(4))); // Double buffer that DMA just used
    float    downsampled_buffer[PIOS_ADC_NUM_CHANNELS]  __attribute__((aligned(4)));
    uint8_t  downsampleStep; // allows to reduce the downsampling buffer by operating in two steps
#endif
    enum pios_adc_dev_magic magic;
};

float PIOS_ADC_PinGetVolt(uint32_t pin)
{
    return ((float)PIOS_ADC_PinGet(pin)) * PIOS_ADC_VOLTAGE_SCALE;
}

#if defined(PIOS_INCLUDE_FREERTOS)
struct pios_adc_dev *pios_adc_dev;
#endif

// Private functions
void PIOS_ADC_downsample_data();
static struct pios_adc_dev *PIOS_ADC_Allocate();
static bool PIOS_ADC_validate(struct pios_adc_dev *);

/* Local Variables */
static GPIO_TypeDef *ADC_GPIO_PORT[PIOS_ADC_NUM_PINS] = PIOS_ADC_PORTS;
static const uint32_t ADC_GPIO_PIN[PIOS_ADC_NUM_PINS] = PIOS_ADC_PINS;
static const uint32_t ADC_CHANNEL[PIOS_ADC_NUM_PINS]  = PIOS_ADC_CHANNELS;

static ADC_TypeDef *ADC_MAPPING[PIOS_ADC_NUM_PINS]    = PIOS_ADC_MAPPING;
static const uint32_t ADC_CHANNEL_MAPPING[PIOS_ADC_NUM_PINS] = PIOS_ADC_CHANNEL_MAPPING;

static bool PIOS_ADC_validate(struct pios_adc_dev *dev)
{
    if (dev == NULL) {
        return false;
    }

    return dev->magic == PIOS_ADC_DEV_MAGIC;
}

#if defined(PIOS_INCLUDE_FREERTOS)
static struct pios_adc_dev *PIOS_ADC_Allocate()
{
    struct pios_adc_dev *adc_dev;

    adc_dev = (struct pios_adc_dev *)pios_malloc(sizeof(*adc_dev));
    if (!adc_dev) {
        return NULL;
    }

    adc_dev->magic = PIOS_ADC_DEV_MAGIC;
    return adc_dev;
}
#else
#error Not implemented
#endif

/**
 * @brief Initialise the ADC Peripheral, configure to run at the max oversampling
 */
int32_t PIOS_ADC_Init(const struct pios_adc_cfg *cfg)
{
    pios_adc_dev = PIOS_ADC_Allocate();
    if (pios_adc_dev == NULL) {
        return -1;
    }

    pios_adc_dev->cfg = cfg;
    pios_adc_dev->callback_function = NULL;

#if defined(PIOS_INCLUDE_FREERTOS)
    pios_adc_dev->data_queue = NULL;
#endif

    /* Setup analog pins */
    GPIO_InitTypeDef GPIO_InitStructure;
    GPIO_StructInit(&GPIO_InitStructure);
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_2MHz;
    GPIO_InitStructure.GPIO_Mode  = GPIO_Mode_AIN;

    /* Enable each ADC pin in the array */
    for (int32_t i = 0; i < PIOS_ADC_NUM_PINS; i++) {
        GPIO_InitStructure.GPIO_Pin = ADC_GPIO_PIN[i];
        GPIO_Init(ADC_GPIO_PORT[i], &GPIO_InitStructure);
    }

    PIOS_ADC_Config(PIOS_ADC_MAX_OVERSAMPLING);
    return 0;
}

/**
 * @brief Configure the ADC to run at a fixed oversampling
 * @param[in] oversampling the amount of oversampling to run at
 */
void PIOS_ADC_Config(uint32_t oversampling)
{
    // Ensure oversample is an even number
    PIOS_Assert(!(oversampling & 0x1));
    pios_adc_dev->adc_oversample = (oversampling > PIOS_ADC_MAX_OVERSAMPLING) ? PIOS_ADC_MAX_OVERSAMPLING : oversampling;
    pios_adc_dev->adc_oversample_block_size = pios_adc_dev->adc_oversample / 2;
    ADC_DeInit(ADC1);
    ADC_DeInit(ADC2);

    /* Disable interrupts */
    DMA_ITConfig(pios_adc_dev->cfg->dma.rx.channel, pios_adc_dev->cfg->dma.irq.flags, DISABLE);

    /* Enable ADC clocks */
    PIOS_ADC_CLOCK_FUNCTION;

    /* Map channels to conversion slots depending on the channel selection mask */
    for (int32_t i = 0; i < PIOS_ADC_NUM_PINS; i++) {
        ADC_RegularChannelConfig(ADC_MAPPING[i], ADC_CHANNEL[i],
                                 ADC_CHANNEL_MAPPING[i],
                                 PIOS_ADC_SAMPLE_TIME);
    }

#if (PIOS_ADC_USE_TEMP_SENSOR)
    ADC_TempSensorVrefintCmd(ENABLE);
    ADC_RegularChannelConfig(PIOS_ADC_TEMP_SENSOR_ADC, ADC_Channel_16,
                             PIOS_ADC_TEMP_SENSOR_ADC_CHANNEL,
                             PIOS_ADC_SAMPLE_TIME);
#endif
    // return
    /* Configure ADCs */
    ADC_InitTypeDef ADC_InitStructure;
    ADC_StructInit(&ADC_InitStructure);
    ADC_InitStructure.ADC_Mode = ADC_Mode_RegSimult;
    ADC_InitStructure.ADC_ScanConvMode       = ENABLE;
    ADC_InitStructure.ADC_ContinuousConvMode = ENABLE;
    ADC_InitStructure.ADC_ExternalTrigConv   = ADC_ExternalTrigConv_None;
    ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
    ADC_InitStructure.ADC_NbrOfChannel       = ((PIOS_ADC_NUM_CHANNELS + 1) >> 1);
    ADC_Init(ADC1, &ADC_InitStructure);

#if (PIOS_ADC_USE_ADC2)
    ADC_Init(ADC2, &ADC_InitStructure);

    /* Enable ADC2 external trigger conversion (to synch with ADC1) */
    ADC_ExternalTrigConvCmd(ADC2, ENABLE);
#endif

    RCC_ADCCLKConfig(PIOS_ADC_ADCCLK);

    /* Enable ADC1->DMA request */
    ADC_DMACmd(ADC1, ENABLE);

    /* ADC1 calibration */
    ADC_Cmd(ADC1, ENABLE);
    ADC_ResetCalibration(ADC1);
    while (ADC_GetResetCalibrationStatus(ADC1)) {
        ;
    }
    ADC_StartCalibration(ADC1);
    while (ADC_GetCalibrationStatus(ADC1)) {
        ;
    }

#if (PIOS_ADC_USE_ADC2)
    /* ADC2 calibration */
    ADC_Cmd(ADC2, ENABLE);
    ADC_ResetCalibration(ADC2);
    while (ADC_GetResetCalibrationStatus(ADC2)) {
        ;
    }
    ADC_StartCalibration(ADC2);
    while (ADC_GetCalibrationStatus(ADC2)) {
        ;
    }
#endif

    /* This makes sure we have an even number of transfers if using ADC2 */
    pios_adc_dev->dma_block_size = ((PIOS_ADC_NUM_CHANNELS + PIOS_ADC_USE_ADC2) >> PIOS_ADC_USE_ADC2) << PIOS_ADC_USE_ADC2;
    pios_adc_dev->dma_half_buffer_size = pios_adc_dev->dma_block_size * pios_adc_dev->adc_oversample_block_size;

    /* Configure DMA channel */
    DMA_InitTypeDef dma_init = pios_adc_dev->cfg->dma.rx.init;
    dma_init.DMA_MemoryBaseAddr = (uint32_t)&pios_adc_dev->raw_data_buffer[0];
    dma_init.DMA_MemoryInc = DMA_MemoryInc_Enable;
    dma_init.DMA_BufferSize     = pios_adc_dev->dma_half_buffer_size; /* x2 for double buffer /2 for 32-bit xfr */
    DMA_Init(pios_adc_dev->cfg->dma.rx.channel, &dma_init);
    DMA_Cmd(pios_adc_dev->cfg->dma.rx.channel, ENABLE);

    /* Trigger interrupt when for half conversions too to indicate double buffer */
    DMA_ITConfig(pios_adc_dev->cfg->dma.rx.channel, DMA_IT_TC, ENABLE);
    DMA_ITConfig(pios_adc_dev->cfg->dma.rx.channel, DMA_IT_HT, ENABLE);

    /* Configure DMA interrupt */
    NVIC_Init(&pios_adc_dev->cfg->dma.irq.init);

    /* Finally start initial conversion */
    ADC_SoftwareStartConvCmd(ADC1, ENABLE);

    /* Use simple averaging filter for now */
    for (int32_t i = 0; i < pios_adc_dev->adc_oversample; i++) {
        pios_adc_dev->fir_coeffs[i] = 1;
    }
    pios_adc_dev->fir_coeffs[pios_adc_dev->adc_oversample] = pios_adc_dev->adc_oversample;

    /* Enable DMA1 clock */
    RCC_AHBPeriphClockCmd(pios_adc_dev->cfg->dma.ahb_clk, ENABLE);
}

/**
 * Returns value of an ADC Pin
 * \param[in] pin number
 * \return ADC pin value - resolution depends on the selected oversampling rate
 * \return -1 if pin doesn't exist
 */
int32_t PIOS_ADC_PinGet(uint32_t pin)
{
    /* Check if pin exists */
    if (pin >= PIOS_ADC_NUM_CHANNELS) {
        return -1;
    }

    /* Return last conversion result */
    return pios_adc_dev->downsampled_buffer[pin];
}

/**
 * @brief Set a callback function that is executed whenever
 * the ADC double buffer swaps
 */
void PIOS_ADC_SetCallback(ADCCallback new_function)
{
    pios_adc_dev->callback_function = new_function;
}

#if defined(PIOS_INCLUDE_FREERTOS)
/**
 * @brief Register a queue to add data to when downsampled
 */
void PIOS_ADC_SetQueue(xQueueHandle data_queue)
{
    pios_adc_dev->data_queue = data_queue;
}
#endif

/**
 * @brief Return the address of the downsampled data buffer
 */
float *PIOS_ADC_GetBuffer(void)
{
    return pios_adc_dev->downsampled_buffer;
}

/**
 * @brief Return the address of the raw data data buffer
 */
int16_t *PIOS_ADC_GetRawBuffer(void)
{
    return (int16_t *)pios_adc_dev->valid_data_buffer;
}

/**
 * @brief Return the amount of over sampling
 */
uint8_t PIOS_ADC_GetOverSampling(void)
{
    return pios_adc_dev->adc_oversample;
}

/**
 * @brief Set the fir coefficients.  Takes as many samples as the
 * current filter order plus one (normalization)
 *
 * @param new_filter Array of adc_oversampling floats plus one for the
 * filter coefficients
 */
void PIOS_ADC_SetFIRCoefficients(float *new_filter)
{
    // Less than or equal to get normalization constant
    for (int i = 0; i <= pios_adc_dev->adc_oversample; i++) {
        pios_adc_dev->fir_coeffs[i] = new_filter[i];
    }
}


/**
 * @brief Downsample the data for each of the channels then call
 * callback function if installed
 */
__attribute__((optimize("O3")))
void PIOS_ADC_downsample_data()
{
    uint16_t chan;
    uint16_t sample;
    float *downsampled_buffer = &pios_adc_dev->downsampled_buffer[0];
    static int32_t sum[PIOS_ADC_NUM_CHANNELS] = { 0 };

    if (pios_adc_dev->downsampleStep == 0) {
        for (uint8_t i = 0; i < PIOS_ADC_NUM_CHANNELS; i++) {
            sum[i] = 0;
        }
    }

    for (sample = 0; sample < pios_adc_dev->adc_oversample_block_size; sample++) {
        const uint16_t *buffer  = (const uint16_t *)&pios_adc_dev->valid_data_buffer[sample * pios_adc_dev->dma_block_size];
        const uint16_t firCoeff = pios_adc_dev->fir_coeffs[sample + PIOS_ADC_NUM_CHANNELS * pios_adc_dev->downsampleStep];
#if (PIOS_ADC_USE_TEMP_SENSOR)
        for (chan = 1; chan < PIOS_ADC_NUM_CHANNELS; chan++) {
#else
        for (chan = 0; chan < PIOS_ADC_NUM_CHANNELS; chan++) {
#endif
            sum[chan] += buffer[chan] * firCoeff;
        }
    }
    // Full downsampling + fir filter is a little bit overwhelming for temp sensor.
    if (pios_adc_dev->downsampleStep == 0) {
        // first part of downsampling done. wait until the second block of samples is acquired
        pios_adc_dev->downsampleStep = 1;
        return;
    }
    pios_adc_dev->downsampleStep = 0;
#if (PIOS_ADC_USE_TEMP_SENSOR)
    for (chan = 1; chan < PIOS_ADC_NUM_CHANNELS; chan++) {
    #else
    for (chan = 0; chan < PIOS_ADC_NUM_CHANNELS; chan++) {
    #endif
        downsampled_buffer[chan] = (float)sum[chan] / (pios_adc_dev->fir_coeffs[pios_adc_dev->adc_oversample]);
    }

    #if (PIOS_ADC_USE_TEMP_SENSOR)
    downsampled_buffer[0] = pios_adc_dev->valid_data_buffer[0];
    #endif

#if defined(PIOS_INCLUDE_FREERTOS)
    if (pios_adc_dev->data_queue) {
        static portBASE_TYPE xHigherPriorityTaskWoken;
        xQueueSendFromISR(pios_adc_dev->data_queue, pios_adc_dev->downsampled_buffer, &xHigherPriorityTaskWoken);
        portEND_SWITCHING_ISR(xHigherPriorityTaskWoken);
    }
#endif
    if (pios_adc_dev->callback_function) {
        pios_adc_dev->callback_function(pios_adc_dev->downsampled_buffer);
    }
}

/**
 * @brief Interrupt for half and full buffer transfer
 *
 * This interrupt handler swaps between the two halfs of the double buffer to make
 * sure the ahrs uses the most recent data.  Only swaps data when AHRS is idle, but
 * really this is a pretense of a sanity check since the DMA engine is consantly
 * running in the background.  Keep an eye on the ekf_too_slow variable to make sure
 * it's keeping up.
 */
void PIOS_ADC_DMA_Handler(void)
{
    if (!PIOS_ADC_validate(pios_adc_dev)) {
        return;
    }

    if (DMA_GetFlagStatus(pios_adc_dev->cfg->full_flag /*DMA1_IT_TC1*/)) { // whole double buffer filled
        pios_adc_dev->valid_data_buffer = &pios_adc_dev->raw_data_buffer[pios_adc_dev->dma_half_buffer_size];
        DMA_ClearFlag(pios_adc_dev->cfg->full_flag);
        PIOS_ADC_downsample_data();
    } else if (DMA_GetFlagStatus(pios_adc_dev->cfg->half_flag /*DMA1_IT_HT1*/)) {
        pios_adc_dev->valid_data_buffer = &pios_adc_dev->raw_data_buffer[0];
        DMA_ClearFlag(pios_adc_dev->cfg->half_flag);
        PIOS_ADC_downsample_data();
    } else {
        // This should not happen, probably due to transfer errors
        DMA_ClearFlag(pios_adc_dev->cfg->dma.irq.flags /*DMA1_FLAG_GL1*/);
    }
}

#endif /* PIOS_INCLUDE_ADC */

/**
 * @}
 * @}
 */