sta-core/src/devices/stm32/bus/spi.cpp

#include <sta/devices/stm32/bus/spi.hpp>
#ifdef STA_STM32_SPI_ENABLED

#include <sta/debug/assert.hpp>
#include <sta/endian.hpp>
#include <sta/lang.hpp>


#ifdef STA_MCU_LITTLE_ENDIAN
#  define STA_STM32_SPI_REVERSE_BIT_ORDER   SPIBitOrder::MSB
#elif STA_MCU_BIG_ENDIAN
#  define STA_STM32_SPI_REVERSE_BIT_ORDER   SPIBitOrder::LSB
#endif


namespace sta
{
    static SPISettings getSPISettings(SPI_HandleTypeDef * handle, uint32_t pclkFreq)
    {
        SPISettings settings;

        settings.mode        = getSPIMode(
            (handle->Init.CLKPolarity == SPI_POLARITY_LOW) ? SPIClkPolarity::LOW : SPIClkPolarity::HIGH,
            (handle->Init.CLKPhase == SPI_PHASE_1EDGE) ? SPIClkPhase::EDGE_1 : SPIClkPhase::EDGE_2
        );
        settings.dataSize    = (handle->Init.DataSize == SPI_DATASIZE_8BIT) ? SPIDataSize::SIZE_8 : SPIDataSize::SIZE_16;
        settings.bitOrder    = (handle->Init.FirstBit == SPI_FIRSTBIT_MSB) ? SPIBitOrder::MSB : SPIBitOrder::LSB;

        uint32_t prescaler = 1;
        switch (handle->Init.BaudRatePrescaler)
        {
        case SPI_BAUDRATEPRESCALER_2:
            prescaler = 2;
            break;
        case SPI_BAUDRATEPRESCALER_4:
            prescaler = 4;
            break;
        case SPI_BAUDRATEPRESCALER_8:
            prescaler = 8;
            break;
        case SPI_BAUDRATEPRESCALER_16:
            prescaler = 16;
            break;
        case SPI_BAUDRATEPRESCALER_32:
            prescaler = 32;
            break;
        case SPI_BAUDRATEPRESCALER_64:
            prescaler = 64;
            break;
        case SPI_BAUDRATEPRESCALER_128:
            prescaler = 128;
            break;
        case SPI_BAUDRATEPRESCALER_256:
            prescaler = 256;
            break;
        default:
            // Unreachable case
            STA_ASSERT_MSG(false, "Case for SPI_BAUDRATEPRESCALER not handled");
            STA_UNREACHABLE();
        }

        // SPI clock speed is based of PCLK
        settings.clkSpeed = pclkFreq / prescaler;

        return settings;
    }


    STM32SPI::STM32SPI(SPI_HandleTypeDef * handle, uint32_t pclkFreq, Mutex * mutex)
        : SPI(getSPISettings(handle, pclkFreq), mutex), handle_{handle}
    {
        STA_ASSERT(handle != nullptr);
    }

    STM32SPI::STM32SPI(const Info & info, Mutex * mutex /* = nullptr */)
        : STM32SPI(info.handle, info.pclkFreq, mutex)
    {}


    bool STM32SPI::transfer(uint8_t value, uint32_t timeout /* = STA_MAX_TIMEOUT */)
    {
        if (settings().dataSize == SPIDataSize::SIZE_8)
        {
            return HAL_SPI_Transmit(handle_, &value, 1, timeout) == HAL_OK;
        }
        else
        {
            // Required since tx buffer is cast to uint16_t * internally
            uint16_t dummy = value;
            return HAL_SPI_Transmit(handle_, reinterpret_cast<uint8_t *>(&dummy), 1, timeout) == HAL_OK;
        }
    }

    bool STM32SPI::transfer16(uint16_t value, uint32_t timeout /* = STA_MAX_TIMEOUT */)
    {
        uint16_t size = 1;

        // Send as two bytes if data size is 8-bit
        if (settings().dataSize == SPIDataSize::SIZE_8)
        {
            size = 2;

            if (settings().bitOrder == STA_STM32_SPI_REVERSE_BIT_ORDER)
            {
                // Reverse byte order from internal representation
                value = STA_UINT16_SWAP_BYTE_ORDER(value);
            }
        }

        return HAL_SPI_Transmit(handle_, reinterpret_cast<uint8_t *>(&value), size, timeout) == HAL_OK;
    }

    bool STM32SPI::transfer(const uint8_t * buffer, size_t size, uint32_t timeout /* = STA_MAX_TIMEOUT */)
    {
        STA_ASSERT(buffer != nullptr);
        STA_ASSERT(size != 0);

        return HAL_SPI_Transmit(handle_, const_cast<uint8_t *>(buffer), size, timeout) == HAL_OK;
    }

    bool STM32SPI::transfer(const uint8_t * txBuffer, uint8_t * rxBuffer, size_t size, uint32_t timeout /* = STA_MAX_TIMEOUT */)
    {
        STA_ASSERT(txBuffer != nullptr);
        STA_ASSERT(rxBuffer != nullptr);
        STA_ASSERT(size != 0);

        return HAL_SPI_TransmitReceive(handle_, const_cast<uint8_t *>(txBuffer), rxBuffer, size, timeout) == HAL_OK;
    }

    bool STM32SPI::receive(uint8_t * buffer, size_t size, uint32_t timeout /* = STA_MAX_TIMEOUT */)
    {
        STA_ASSERT(buffer != nullptr);

        return HAL_SPI_Receive(handle_, buffer, size, timeout) == HAL_OK;
    }

    bool STM32SPI::fill(uint8_t value, size_t count, uint32_t timeout /* = STA_MAX_TIMEOUT */)
    {
        STA_ASSERT(count != 0);

        if (settings().dataSize == SPIDataSize::SIZE_8)
        {
            for (size_t i = 0; i < count; ++i)
            {
                return HAL_SPI_Transmit(handle_, &value, 1, timeout) == HAL_OK;
            }
        }
        else
        {
            // Required since tx buffer is cast to uint16_t * internally
            uint16_t dummy = value;
            for (size_t i = 0; i < count; ++i)
            {
                return HAL_SPI_Transmit(handle_, reinterpret_cast<uint8_t *>(&dummy), 1, timeout) == HAL_OK;
            }
        }
    }

    STM32SPIDevice::STM32SPIDevice(STM32SPI * intf, STM32GpioPin * csPin)
        : SPIDevice(intf, csPin)
    {}
} // namespace sta


#endif // STA_STM32_SPI_ENABLED