/*
 * upstream_spi.c
 *
 *  Created on: 21/06/2015
 *      Author: Robert Fisk
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/.
 */

#include "upstream_interface_def.h"
#include "upstream_spi.h"
#include "stm32f4xx_hal.h"
#include "board_config.h"
#include "interrupts.h"



SPI_HandleTypeDef           Hspi1;
UpstreamPacketTypeDef       UpstreamPacket0;
UpstreamPacketTypeDef       UpstreamPacket1;
UpstreamPacketTypeDef*      CurrentWorkingPacket;
UpstreamPacketTypeDef*      NextTxPacket        = NULL;         //Indicates we have a pending TX packet

InterfaceStateTypeDef               UpstreamInterfaceState      = UPSTREAM_INTERFACE_IDLE;
FreePacketCallbackTypeDef           PendingFreePacketCallback   = NULL; //Indicates someone is waiting for a packet buffer to become available
SpiPacketReceivedCallbackTypeDef    ReceivePacketCallback       = NULL; //Indicates someone is waiting for a received packet

uint32_t                    TemporaryIncomingPacketLength;      //We don't actually care about what Downstream sends us when we are transmitting. We just need somewhere to put it so that our own packet length is not overwritten.
uint8_t                     TxOkInterruptReceived = 0;
uint8_t                     SentCommandClass;
uint8_t                     SentCommand;


void Upstream_BeginTransmitPacketSize(void);
void Upstream_BeginTransmitPacketBody(void);
HAL_StatusTypeDef Upstream_CheckBeginPacketReception(void);
void Upstream_BeginReceivePacketSize(UpstreamPacketTypeDef* freePacket);
void Upstream_BeginReceivePacketBody(void);



void Upstream_InitSPI(void)
{
    UpstreamPacket0.Busy = NOT_BUSY;
    UpstreamPacket1.Busy = NOT_BUSY;

    Hspi1.Instance = SPI1;
    Hspi1.State = HAL_SPI_STATE_RESET;
    Hspi1.Init.Mode = SPI_MODE_MASTER;
    Hspi1.Init.Direction = SPI_DIRECTION_2LINES;
    Hspi1.Init.DataSize = SPI_DATASIZE_16BIT;
    Hspi1.Init.CLKPolarity = SPI_POLARITY_LOW;
    Hspi1.Init.CLKPhase = SPI_PHASE_1EDGE;
    Hspi1.Init.NSS = SPI_NSS_SOFT;
    Hspi1.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_4; //42MHz APB2 / 4 = 10.5Mbaud
    Hspi1.Init.FirstBit = SPI_FIRSTBIT_MSB;
    Hspi1.Init.TIMode = SPI_TIMODE_DISABLED;
    Hspi1.Init.CRCCalculation = SPI_CRCCALCULATION_ENABLED;
    Hspi1.Init.CRCPolynomial = SPI_CRC_DEFAULTPOLYNOMIAL;
    HAL_SPI_Init(&Hspi1);

    if (DOWNSTREAM_TX_OK_ACTIVE)
    {
        TxOkInterruptReceived = 1;
    }
}



//Used by USB interface classes, and by our internal RX code.
HAL_StatusTypeDef Upstream_GetFreePacket(FreePacketCallbackTypeDef callback)
{
    if (UpstreamInterfaceState >= UPSTREAM_INTERFACE_ERROR)
    {
        return HAL_ERROR;
    }

    //Do we already have a queued callback?
    if (PendingFreePacketCallback != NULL)
    {
        UPSTREAM_SPI_FREAKOUT;
        return HAL_ERROR;
    }

    //Check if there is a free buffer now
    if (UpstreamPacket0.Busy == NOT_BUSY)
    {
        UpstreamPacket0.Busy = BUSY;
        callback(&UpstreamPacket0);
        return HAL_OK;
    }
    if (UpstreamPacket1.Busy == NOT_BUSY)
    {
        UpstreamPacket1.Busy = BUSY;
        callback(&UpstreamPacket1);
        return HAL_OK;
    }

    //Otherwise save requested address for when a buffer becomes free in the future
    PendingFreePacketCallback = callback;
    return HAL_OK;
}


UpstreamPacketTypeDef* Upstream_GetFreePacketImmediately(void)
{
    if (UpstreamInterfaceState >= UPSTREAM_INTERFACE_ERROR)
    {
        return NULL;
    }

    //We are expecting a free buffer now
    if (UpstreamPacket0.Busy == NOT_BUSY)
    {
        UpstreamPacket0.Busy = BUSY;
        return &UpstreamPacket0;
    }
    if (UpstreamPacket1.Busy == NOT_BUSY)
    {
        UpstreamPacket1.Busy = BUSY;
        return &UpstreamPacket1;
    }

    //Should not happen:
    UPSTREAM_SPI_FREAKOUT;
    return NULL;
}


//Used by USB interface classes, and by our internal RX code.
void Upstream_ReleasePacket(UpstreamPacketTypeDef* packetToRelease)
{
    FreePacketCallbackTypeDef tempCallback;
    
    if (UpstreamInterfaceState >= UPSTREAM_INTERFACE_ERROR)
    {
        return;
    }

    if ((packetToRelease != &UpstreamPacket0) &&
        (packetToRelease != &UpstreamPacket1))
    {
        UPSTREAM_SPI_FREAKOUT;
        return;
    }

    if (packetToRelease->Busy != BUSY)
    {
        UPSTREAM_SPI_FREAKOUT;
        return;
    }

    if (PendingFreePacketCallback != NULL)
    {
        tempCallback = PendingFreePacketCallback;   //In extreme situations, running this callback can trigger another request for a free packet,
        PendingFreePacketCallback = NULL;           //thereby causing GetFreePacket to freak out. So we need to clear the callback indicator first.
        tempCallback(packetToRelease);
    }
    else
    {
        packetToRelease->Busy = NOT_BUSY;
    }
}


//Used by USB interface classes only.
//OK to call when still transmitting another packet.
//Not OK to call when receiving or waiting for downstream reply,
//as we can't let the size/packet sequence get out of sync.
HAL_StatusTypeDef Upstream_TransmitPacket(UpstreamPacketTypeDef* packetToWrite)
{
    if (UpstreamInterfaceState >= UPSTREAM_INTERFACE_ERROR)
    {
        return HAL_ERROR;
    }
    
    //Sanity checks
    if ((packetToWrite != &UpstreamPacket0) &&
        (packetToWrite != &UpstreamPacket1))
    {
        UPSTREAM_SPI_FREAKOUT;
        return HAL_ERROR;
    }
    if ((packetToWrite->Busy != BUSY) ||
        (packetToWrite->Length16 < UPSTREAM_PACKET_LEN_MIN_16) ||
        (packetToWrite->Length16 > UPSTREAM_PACKET_LEN_16))
    {
        UPSTREAM_SPI_FREAKOUT;
        return HAL_ERROR;
    }
    if (NextTxPacket != NULL)
    {
        UPSTREAM_SPI_FREAKOUT;
        return HAL_ERROR;
    }

    switch (UpstreamInterfaceState)
    {
    case UPSTREAM_INTERFACE_TX_SIZE_WAIT:
    case UPSTREAM_INTERFACE_TX_SIZE:
    case UPSTREAM_INTERFACE_TX_PACKET_WAIT:
    case UPSTREAM_INTERFACE_TX_PACKET:
        NextTxPacket = packetToWrite;
        break;

    case UPSTREAM_INTERFACE_IDLE:
        UpstreamInterfaceState = UPSTREAM_INTERFACE_TX_SIZE_WAIT;
        CurrentWorkingPacket = packetToWrite;
        SentCommandClass = CurrentWorkingPacket->CommandClass;
        SentCommand = CurrentWorkingPacket->Command;

        //Downstream may have set TxOk pin before we wanted to transmit.
        //In this case we can go ahead and transmit now.
        if (TxOkInterruptReceived)
        {
            TxOkInterruptReceived = 0;
            Upstream_BeginTransmitPacketSize();
        }
        break;

    default:
        UPSTREAM_SPI_FREAKOUT;
        return HAL_ERROR;
    }
    return HAL_OK;
}



//Called at the end of the SPI TxRx transfer,
//at SPI1 interrupt priority. Assume *hspi points to our hspi1.
//We TxRx our outgoing packet because the SPI hardware freaks out if we only Tx it :-/
void HAL_SPI_TxRxCpltCallback(SPI_HandleTypeDef *hspi)
{
    UNUSED(hspi);
    SpiPacketReceivedCallbackTypeDef tempPacketCallback;
    UpstreamPacketTypeDef* tempPacketToFree;

    SPI1_NSS_DEASSERT;

    if (UpstreamInterfaceState >= UPSTREAM_INTERFACE_ERROR)
    {
        return;
    }

    //Finished transmitting packet size
    if (UpstreamInterfaceState == UPSTREAM_INTERFACE_TX_SIZE)
    {
        UpstreamInterfaceState = UPSTREAM_INTERFACE_TX_PACKET_WAIT;
        if (TxOkInterruptReceived)
        {
            TxOkInterruptReceived = 0;
            Upstream_BeginTransmitPacketBody();
        }
        return;
    }

    //Finished transmitting packet body
    if (UpstreamInterfaceState == UPSTREAM_INTERFACE_TX_PACKET)
    {
        if ((PendingFreePacketCallback != NULL) && (NextTxPacket == NULL))
        {
            UPSTREAM_SPI_FREAKOUT;
            return;
        }

        tempPacketToFree = CurrentWorkingPacket;

        if (NextTxPacket != NULL)
        {
            //NextTxPacket has already passed the checks in Upstream_TransmitPacket.
            //So we just need to pass it to HAL_SPI_Transmit_DMA.
            UpstreamInterfaceState = UPSTREAM_INTERFACE_TX_SIZE_WAIT;
            CurrentWorkingPacket = NextTxPacket;
            NextTxPacket = NULL;
            SentCommandClass = CurrentWorkingPacket->CommandClass;
            SentCommand = CurrentWorkingPacket->Command;
            if (TxOkInterruptReceived)
            {
                TxOkInterruptReceived = 0;
                Upstream_BeginTransmitPacketSize();
            }
        }
        else
        {
            //No packet queued for transmission:
            UpstreamInterfaceState = UPSTREAM_INTERFACE_IDLE;
            if (ReceivePacketCallback != NULL)
            {
                Upstream_CheckBeginPacketReception();
            }
        }

        //Release old packet after moving Next to Current
        Upstream_ReleasePacket(tempPacketToFree);
        return;
    }
    


    if (UpstreamInterfaceState == UPSTREAM_INTERFACE_RX_SIZE)
    {
        if ((CurrentWorkingPacket->Length16 < UPSTREAM_PACKET_LEN_MIN_16) ||
            (CurrentWorkingPacket->Length16 > UPSTREAM_PACKET_LEN_16))
        {
            UPSTREAM_SPI_FREAKOUT;
            return;
        }
        UpstreamInterfaceState = UPSTREAM_INTERFACE_RX_PACKET_WAIT;
        if (TxOkInterruptReceived)
        {
            TxOkInterruptReceived = 0;
            Upstream_BeginReceivePacketBody();
        }
        return;
    }

    if (UpstreamInterfaceState == UPSTREAM_INTERFACE_RX_PACKET)
    {
        UpstreamInterfaceState = UPSTREAM_INTERFACE_IDLE;
        if (ReceivePacketCallback == NULL)
        {
            UPSTREAM_SPI_FREAKOUT;
            return;
        }

        if ((CurrentWorkingPacket->CommandClass == COMMAND_CLASS_ERROR) &&
            (CurrentWorkingPacket->Command == COMMAND_ERROR_DEVICE_DISCONNECTED))
        {
            Upstream_ReleasePacket(CurrentWorkingPacket);
            ReceivePacketCallback = NULL;
            Upstream_StateMachine_DeviceDisconnected();
            return;
        }

        if (((CurrentWorkingPacket->CommandClass & COMMAND_CLASS_MASK) != (SentCommandClass & COMMAND_CLASS_MASK)) ||
            (CurrentWorkingPacket->Command != SentCommand))
        {
            UPSTREAM_SPI_FREAKOUT;
            Upstream_ReleasePacket(CurrentWorkingPacket);
            CurrentWorkingPacket = NULL;        //Call back with a NULL packet to indicate error
        }

        //USB interface may want to receive another packet immediately,
        //so clear ReceivePacketCallback before the call.
        //It is the callback's responsibility to release the packet buffer we are passing to it!
        tempPacketCallback = ReceivePacketCallback;
        ReceivePacketCallback = NULL;
        tempPacketCallback(CurrentWorkingPacket);
        return;
    }


    //case default:
    UPSTREAM_SPI_FREAKOUT;
}


//Used by USB interface classes.
//Ok to call when idle or transmitting.
//Not OK to call when receiving or waiting for downstream reply.
HAL_StatusTypeDef Upstream_ReceivePacket(SpiPacketReceivedCallbackTypeDef callback)
{
    if (UpstreamInterfaceState >= UPSTREAM_INTERFACE_ERROR)
    {
        return HAL_ERROR;
    }
    
    if (ReceivePacketCallback != NULL)
    {
        UPSTREAM_SPI_FREAKOUT;
        return HAL_ERROR;
    }

    ReceivePacketCallback = callback;
    return Upstream_CheckBeginPacketReception();
}


//Internal use only.
HAL_StatusTypeDef Upstream_CheckBeginPacketReception(void)
{
    if (UpstreamInterfaceState >= UPSTREAM_INTERFACE_ERROR)
    {
        return HAL_ERROR;
    }
    
    if (UpstreamInterfaceState >= UPSTREAM_INTERFACE_RX_SIZE_WAIT)
    {
        UPSTREAM_SPI_FREAKOUT;
        return HAL_ERROR;
    }

    if (UpstreamInterfaceState == UPSTREAM_INTERFACE_IDLE)
    {
        UpstreamInterfaceState = UPSTREAM_INTERFACE_RX_SIZE_WAIT;
        if (TxOkInterruptReceived)
        {
            TxOkInterruptReceived = 0;
            Upstream_GetFreePacket(Upstream_BeginReceivePacketSize);
        }
    }
    return HAL_OK;
}


//This is called by EXTI3 falling edge interrupt,
//indicating that downstream is ready for the next transaction.
void Upstream_TxOkInterrupt(void)
{
    if (UpstreamInterfaceState >= UPSTREAM_INTERFACE_ERROR)
    {
        return;
    }
    
    switch (UpstreamInterfaceState)
    {
    case UPSTREAM_INTERFACE_IDLE:
        TxOkInterruptReceived = 1;
        break;

    case UPSTREAM_INTERFACE_TX_SIZE_WAIT:
        Upstream_BeginTransmitPacketSize();
        break;

    case UPSTREAM_INTERFACE_TX_PACKET_WAIT:
        Upstream_BeginTransmitPacketBody();
        break;

    case UPSTREAM_INTERFACE_RX_SIZE_WAIT:
        Upstream_GetFreePacket(Upstream_BeginReceivePacketSize);
        break;

    case UPSTREAM_INTERFACE_RX_PACKET_WAIT:
        Upstream_BeginReceivePacketBody();
        break;

    default:
        UPSTREAM_SPI_FREAKOUT;
    }
}


void Upstream_BeginTransmitPacketSize(void)
{
    UpstreamInterfaceState = UPSTREAM_INTERFACE_TX_SIZE;
    SPI1_NSS_ASSERT;
    if (HAL_SPI_TransmitReceive(&Hspi1,
                                    (uint8_t*)&CurrentWorkingPacket->Length16,
                                    (uint8_t*)&TemporaryIncomingPacketLength,
                                    2,                                  //We only need to write one word, but the peripheral library freaks out...
                                    SPI_TIMEOUT_VALUE) != HAL_OK)
    {
        UPSTREAM_SPI_FREAKOUT;
    }

    HAL_SPI_TxRxCpltCallback(&Hspi1);
}


void Upstream_BeginTransmitPacketBody(void)
{
    UpstreamInterfaceState = UPSTREAM_INTERFACE_TX_PACKET;
    SPI1_NSS_ASSERT;

    if (HAL_SPI_TransmitReceive_DMA(&Hspi1,
                                    &CurrentWorkingPacket->CommandClass,
                                    &CurrentWorkingPacket->CommandClass,
                                    ((CurrentWorkingPacket->Length16 < 2) ? 2 : CurrentWorkingPacket->Length16)) != HAL_OK)
    {
        UPSTREAM_SPI_FREAKOUT;
    }
}


//Internal use only.
//Called when we want to receive downstream packet, and a packet buffer has become free.
void Upstream_BeginReceivePacketSize(UpstreamPacketTypeDef* freePacket)
{
    if (UpstreamInterfaceState >= UPSTREAM_INTERFACE_ERROR)
    {
        return;
    }
    
    if (UpstreamInterfaceState != UPSTREAM_INTERFACE_RX_SIZE_WAIT)
    {
        UPSTREAM_SPI_FREAKOUT;
        return;
    }
    UpstreamInterfaceState = UPSTREAM_INTERFACE_RX_SIZE;
    CurrentWorkingPacket = freePacket;
    CurrentWorkingPacket->Length16 = 0;     //Our RX buffer is used by HAL_SPI_TransmitReceive_DMA as dummy TX data, we set Length to 0 so downstream will know this is a dummy packet.
    SPI1_NSS_ASSERT;
    if (HAL_SPI_TransmitReceive(&Hspi1,
                                    (uint8_t*)&CurrentWorkingPacket->Length16,
                                    (uint8_t*)&CurrentWorkingPacket->Length16,
                                    2,                                     //We only need to write one word, but the peripheral library freaks out...
                                    SPI_TIMEOUT_VALUE) != HAL_OK)
    {
        UPSTREAM_SPI_FREAKOUT;
    }

    HAL_SPI_TxRxCpltCallback(&Hspi1);
}


void Upstream_BeginReceivePacketBody(void)
{
    UpstreamInterfaceState = UPSTREAM_INTERFACE_RX_PACKET;
    SPI1_NSS_ASSERT;
    if (HAL_SPI_TransmitReceive_DMA(&Hspi1,
                                    &CurrentWorkingPacket->CommandClass,
                                    &CurrentWorkingPacket->CommandClass,
                                    ((CurrentWorkingPacket->Length16 < 2) ? 2 : CurrentWorkingPacket->Length16)) != HAL_OK)
    {
        UPSTREAM_SPI_FREAKOUT;
    }
}


//Something bad happened! Possibly CRC error...
void HAL_SPI_ErrorCallback(SPI_HandleTypeDef *hspi)
{
    UNUSED(hspi);
    SpiPacketReceivedCallbackTypeDef tempPacketCallback;

    if (UpstreamInterfaceState >= UPSTREAM_INTERFACE_ERROR)
    {
        return;
    }
    
    UPSTREAM_SPI_FREAKOUT;

    if (ReceivePacketCallback != NULL)
    {
        tempPacketCallback = ReceivePacketCallback;
        ReceivePacketCallback = NULL;
        tempPacketCallback(NULL);           //Call back with a NULL packet to indicate error
    }
}