Modbus-rtu/Modbus/Src/modbus_data_store.c

#include "modbus_data_store.h"
#include <stddef.h>

#if defined(PLSR_HOST_TEST)
#define MODBUS_DATA_BARRIER() __sync_synchronize()
#else
#include "stm32f4xx.h"
#define MODBUS_DATA_BARRIER() __DMB()
#endif

#define MODBUS_DATA_SRAM_WORD_COUNT  (20000UL)
#define MODBUS_DATA_CCM_WORD_COUNT   (29999UL)
#define MODBUS_DATA_HD_SRAM_OFFSET   (10000UL)
#define MODBUS_DATA_LINEAR_CCM_BASE  (40000UL)

static uint16_t ModbusDataSram[MODBUS_DATA_SRAM_WORD_COUNT];

#if !defined(PLSR_HOST_TEST)
#pragma location = ".ccmram"
#pragma data_alignment = 4
__root
#endif
static uint16_t ModbusDataCcm[MODBUS_DATA_CCM_WORD_COUNT];

static volatile uint32_t ModbusDataWriteSequence;
static volatile uint32_t ModbusDataWriteFirstAddress;
static volatile uint32_t ModbusDataWriteWordCount;
static volatile MODBUS_DATA_DEVICE ModbusDataWriteDevice;

static uint32_t ModbusDataEnterShortCritical(void)
{
#if defined(PLSR_HOST_TEST)
    return 0UL;
#else
    uint32_t interruptState;

    interruptState = __get_PRIMASK();
    __disable_irq();
    return interruptState;
#endif
}

static void ModbusDataExitShortCritical(uint32_t interruptState)
{
#if defined(PLSR_HOST_TEST)
    (void)interruptState;
#else
    if (interruptState == 0UL)
    {
        __enable_irq();
    }
#endif
}

static uint8_t ModbusDataResolve(MODBUS_DATA_DEVICE device,
                                 uint32_t address,
                                 uint16_t **word)
{
    if (word == NULL)
    {
        return 0U;
    }
    switch (device)
    {
        case MODBUS_DATA_DEVICE_D:
            if (address >= MODBUS_DATA_D_WORD_COUNT)
            {
                return 0U;
            }
            *word = &ModbusDataSram[address];
            return 1U;

        case MODBUS_DATA_DEVICE_HD:
            if (address >= MODBUS_DATA_HD_WORD_COUNT)
            {
                return 0U;
            }
            *word = &ModbusDataSram[MODBUS_DATA_HD_SRAM_OFFSET + address];
            return 1U;

        case MODBUS_DATA_DEVICE_FD:
            if (address >= MODBUS_DATA_FD_WORD_COUNT)
            {
                return 0U;
            }
            *word = &ModbusDataCcm[address];
            return 1U;

        default:
            return 0U;
    }
}

static uint32_t ModbusDataCapacity(MODBUS_DATA_DEVICE device)
{
    switch (device)
    {
        case MODBUS_DATA_DEVICE_D:
            return MODBUS_DATA_D_WORD_COUNT;

        case MODBUS_DATA_DEVICE_HD:
            return MODBUS_DATA_HD_WORD_COUNT;

        case MODBUS_DATA_DEVICE_FD:
            return MODBUS_DATA_FD_WORD_COUNT;

        default:
            return 0UL;
    }
}

static uint8_t ModbusDataWriteOverlaps(MODBUS_DATA_DEVICE device,
                                       uint32_t firstAddress,
                                       uint32_t wordCount)
{
    uint32_t activeFirst;
    uint32_t activeCount;

    if (device != ModbusDataWriteDevice)
    {
        return 0U;
    }
    activeFirst = ModbusDataWriteFirstAddress;
    activeCount = ModbusDataWriteWordCount;
    if ((activeCount == 0UL) || (wordCount == 0UL))
    {
        return 0U;
    }
    return ((firstAddress < (activeFirst + activeCount))
            && (activeFirst < (firstAddress + wordCount)))
               ? 1U
               : 0U;
}

static void ModbusDataWriteBegin(MODBUS_DATA_DEVICE device,
                                 uint32_t firstAddress,
                                 uint32_t wordCount)
{
    ModbusDataWriteDevice = device;
    ModbusDataWriteFirstAddress = firstAddress;
    ModbusDataWriteWordCount = wordCount;
    MODBUS_DATA_BARRIER();
    ModbusDataWriteSequence++;
    MODBUS_DATA_BARRIER();
}

static void ModbusDataWriteEnd(void)
{
    MODBUS_DATA_BARRIER();
    ModbusDataWriteSequence++;
}

uint8_t ModbusDataValidateWords(MODBUS_DATA_DEVICE device,
                                uint32_t firstAddress,
                                uint32_t wordCount)
{
    uint32_t capacity;

    capacity = ModbusDataCapacity(device);
    if ((capacity == 0UL) || (wordCount == 0UL)
        || (firstAddress >= capacity))
    {
        return 0U;
    }
    return (wordCount <= (capacity - firstAddress)) ? 1U : 0U;
}

uint8_t ModbusDataReadWord(MODBUS_DATA_DEVICE device,
                           uint32_t address,
                           uint16_t *value)
{
    uint16_t *word;
    uint32_t before;
    uint32_t after;
    uint16_t snapshot;

    if ((value == NULL) || (ModbusDataResolve(device, address, &word) == 0U))
    {
        return 0U;
    }
    before = ModbusDataWriteSequence;
    if (((before & 1UL) != 0UL)
        && (ModbusDataWriteOverlaps(device, address, 1UL) != 0U))
    {
        return 0U;
    }
    MODBUS_DATA_BARRIER();
    snapshot = *word;
    MODBUS_DATA_BARRIER();
    after = ModbusDataWriteSequence;
    if ((before != after)
        && (ModbusDataWriteOverlaps(device, address, 1UL) != 0U))
    {
        return 0U;
    }
    if (((after & 1UL) != 0UL)
        && (ModbusDataWriteOverlaps(device, address, 1UL) != 0U))
    {
        return 0U;
    }
    *value = snapshot;
    return 1U;
}

uint8_t ModbusDataReadDword(MODBUS_DATA_DEVICE device,
                            uint32_t lowAddress,
                            int32_t *value)
{
    uint16_t *lowWord;
    uint16_t *highWord;
    uint16_t lowSnapshot;
    uint16_t highSnapshot;
    uint32_t before;
    uint32_t after;

    if ((value == NULL)
        || (ModbusDataValidateWords(device, lowAddress, 2UL) == 0U)
        || (ModbusDataResolve(device, lowAddress, &lowWord) == 0U)
        || (ModbusDataResolve(device, lowAddress + 1UL, &highWord) == 0U))
    {
        return 0U;
    }
    before = ModbusDataWriteSequence;
    if (((before & 1UL) != 0UL)
        && (ModbusDataWriteOverlaps(device, lowAddress, 2UL) != 0U))
    {
        return 0U;
    }
    MODBUS_DATA_BARRIER();
    lowSnapshot = *lowWord;
    highSnapshot = *highWord;
    MODBUS_DATA_BARRIER();
    after = ModbusDataWriteSequence;
    if ((before != after)
        && (ModbusDataWriteOverlaps(device, lowAddress, 2UL) != 0U))
    {
        return 0U;
    }
    if (((after & 1UL) != 0UL)
        && (ModbusDataWriteOverlaps(device, lowAddress, 2UL) != 0U))
    {
        return 0U;
    }
    *value = (int32_t)(((uint32_t)highSnapshot << 16U) | lowSnapshot);
    return 1U;
}

uint8_t ModbusDataWriteWord(MODBUS_DATA_DEVICE device,
                            uint32_t address,
                            uint16_t value)
{
    uint16_t *word;
    uint32_t interruptState;

    if (ModbusDataResolve(device, address, &word) == 0U)
    {
        return 0U;
    }
    interruptState = ModbusDataEnterShortCritical();
    ModbusDataWriteBegin(device, address, 1UL);
    *word = value;
    ModbusDataWriteEnd();
    ModbusDataExitShortCritical(interruptState);
    return 1U;
}

uint8_t ModbusDataWriteWords(MODBUS_DATA_DEVICE device,
                             uint32_t firstAddress,
                             const uint16_t *values,
                             uint32_t wordCount)
{
    uint16_t *firstWord;
    uint32_t index;
    uint32_t interruptState = 1UL;

    if ((values == NULL)
        || (ModbusDataValidateWords(device, firstAddress, wordCount) == 0U)
        || (ModbusDataResolve(device, firstAddress, &firstWord) == 0U))
    {
        return 0U;
    }
    /* A live INT32 update is only two words.  Keep that very short commit
     * indivisible to the 100us ISR, so it sees either the old or new value.
     * Larger block writes use the non-blocking sequence protocol instead of
     * delaying pulse-related interrupts for an unbounded block copy. */
    if (wordCount <= 2UL)
    {
        interruptState = ModbusDataEnterShortCritical();
    }
    ModbusDataWriteBegin(device, firstAddress, wordCount);
    for (index = 0UL; index < wordCount; index++)
    {
        firstWord[index] = values[index];
    }
    ModbusDataWriteEnd();
    if (wordCount <= 2UL)
    {
        ModbusDataExitShortCritical(interruptState);
    }
    return 1U;
}

uint8_t ModbusDataReadLinear(uint32_t address, uint16_t *value)
{
    if (address < MODBUS_DATA_SRAM_WORD_COUNT)
    {
        return ModbusDataReadWord((address < MODBUS_DATA_D_WORD_COUNT)
                                      ? MODBUS_DATA_DEVICE_D
                                      : MODBUS_DATA_DEVICE_HD,
                                  (address < MODBUS_DATA_D_WORD_COUNT)
                                      ? address
                                      : address - MODBUS_DATA_HD_SRAM_OFFSET,
                                  value);
    }
    if ((address >= MODBUS_DATA_LINEAR_CCM_BASE)
        && ((address - MODBUS_DATA_LINEAR_CCM_BASE)
            < MODBUS_DATA_CCM_WORD_COUNT))
    {
        uint32_t before;
        uint32_t after;
        uint16_t snapshot;

        if (value == NULL)
        {
            return 0U;
        }
        before = ModbusDataWriteSequence;
        if ((before & 1UL) != 0UL)
        {
            return 0U;
        }
        MODBUS_DATA_BARRIER();
        snapshot = ModbusDataCcm[address - MODBUS_DATA_LINEAR_CCM_BASE];
        MODBUS_DATA_BARRIER();
        after = ModbusDataWriteSequence;
        if ((before != after) || ((after & 1UL) != 0UL))
        {
            return 0U;
        }
        *value = snapshot;
        return 1U;
    }
    return 0U;
}

uint32_t ModbusDataGetWriteSequence(void)
{
    return ModbusDataWriteSequence;
}