/**
* \copyright
* Copyright (c) 2018, Infineon Technologies AG
* All rights reserved.                                                         
*
* This software is provided with terms and conditions as specified in OPTIGA(TM) Trust X Evaluation Kit License Agreement.
* \endcopyright
*
* \author Infineon AG
*
* \file ifx_i2c_transport_layer.c
*
* \brief   This file implements the IFX I2C Transport Layer.
*
* \addtogroup  grIFXI2C
* @{
*/
/***********************************************************************************************************************
* HEADER FILES
**********************************************************************************************************************/
#include "ifx_i2c_transport_layer.h"
#include "ifx_i2c_data_link_layer.h" // include lower layer header

/// @cond hidden
/***********************************************************************************************************************
* MACROS
**********************************************************************************************************************/
// Transport Layer states
#define TL_STATE_UNINIT                     (0x00)
#define TL_STATE_IDLE                       (0x01)
#define TL_STATE_TX                         (0x02)
#define TL_STATE_RX                         (0x04)
#define TL_STATE_CHAINING                   (0x05)
#define TL_STATE_ERROR                      (0x06)
#define TL_STATE_CHAINING_ERROR             (0x07)
#define TL_STATE_RESEND                     (0x08)
// Transport Layer header size
#define TL_HEADER_SIZE                      1

// Transport Layer chaining values
#define TL_CHAINING_NO                      (0x00)
#define TL_CHAINING_FIRST                   (0x01)
#define TL_CHAINING_INTERMEDIATE            (0x02)
#define TL_CHAINING_LAST                    (0x04)
#define TL_CHAINING_ERROR                   (0x07)

#define TL_PCTR_CHANNEL_MASK                (0xF8)
#define TL_PCTR_CHAIN_MASK                  (0x07)
// Setup debug log statements
#if IFX_I2C_LOG_TL == 1
#define LOG_TL IFX_I2C_LOG
#else
#define LOG_TL(...)	//printf(__VA_ARGS__);
#endif
/***********************************************************************************************************************
* ENUMS
**********************************************************************************************************************/
/***********************************************************************************************************************
* DATA STRUCTURES
***********************************************************************************************************************/
static uint8_t pctr_states_table[5][2]={
                                            {TL_CHAINING_NO,TL_CHAINING_LAST},
                                            {TL_CHAINING_NO,TL_CHAINING_LAST},
                                            {TL_CHAINING_FIRST,TL_CHAINING_INTERMEDIATE},
                                            {0xFF,0xFF},
                                            {TL_CHAINING_FIRST,TL_CHAINING_INTERMEDIATE},
                                        };
/***********************************************************************************************************************
* GLOBAL
***********************************************************************************************************************/

/***********************************************************************************************************************
* LOCAL ROUTINES
***********************************************************************************************************************/
/// Sends available fragment
_STATIC_H host_lib_status_t ifx_i2c_tl_send_next_fragment(ifx_i2c_context_t *p_ctx);
/// Datalink Layer event handler
_STATIC_H void ifx_i2c_dl_event_handler(ifx_i2c_context_t* p_ctx,host_lib_status_t event, const uint8_t* p_data, uint16_t data_len);
/// Resends all the packets
_STATIC_H host_lib_status_t ifx_i2c_tl_resend_packets(ifx_i2c_context_t *p_ctx);
/// Sends chaining error to I2C slave
_STATIC_H host_lib_status_t ifx_i2c_tl_send_chaining_error(ifx_i2c_context_t *p_ctx);
/// Calculates the pctr value
_STATIC_H uint8_t ifx_i2c_tl_calculate_pctr(const ifx_i2c_context_t *p_ctx);
/// Checks if chaining error occured based on current and previous pctr
_STATIC_H host_lib_status_t ifx_i2c_tl_check_chaining_error(uint8_t current_chaning, uint8_t previous_chaining);
/// @endcond
/***********************************************************************************************************************
* API PROTOTYPES
**********************************************************************************************************************/
/// Transport Layer initialization function
host_lib_status_t ifx_i2c_tl_init(ifx_i2c_context_t *p_ctx,ifx_i2c_event_handler_t handler)
{
    LOG_TL("[IFX-TL]: Init\n");
	
    p_ctx->tl.state = TL_STATE_UNINIT;
    
    // Initialize Data Link layer (and register event handler)
    if (ifx_i2c_dl_init(p_ctx,ifx_i2c_dl_event_handler) != IFX_I2C_STACK_SUCCESS)
    {
        return IFX_I2C_STACK_ERROR;
    }

    p_ctx->tl.upper_layer_event_handler = handler;
    p_ctx->tl.state                     = TL_STATE_IDLE;
    p_ctx->tl.max_packet_length = p_ctx->frame_size - (DL_HEADER_SIZE + TL_HEADER_SIZE);

    return IFX_I2C_STACK_SUCCESS;
}


host_lib_status_t ifx_i2c_tl_transceive(ifx_i2c_context_t *p_ctx,uint8_t* p_packet, uint16_t packet_len,
                               uint8_t* p_recv_packet, uint16_t* recv_packet_len)
{
    host_lib_status_t status = IFX_I2C_STACK_ERROR;
    LOG_TL("[IFX-TL]: Transceive txlen %d\n", packet_len);

    do
    {
        // Check function arguments
        if (p_packet == NULL || packet_len == 0 )
        {
            break;
        }   
        // Transport Layer must be idle
        if (p_ctx->tl.state != TL_STATE_IDLE)
        {
            break;
        }    
        p_ctx->tl.state = TL_STATE_TX;
        p_ctx->tl.api_start_time = pal_os_timer_get_time_in_milliseconds();    
        p_ctx->tl.p_actual_packet = p_packet;
        p_ctx->tl.actual_packet_length = packet_len;
        p_ctx->tl.packet_offset = 0; 
        p_ctx->tl.p_recv_packet_buffer = p_recv_packet;
        p_ctx->tl.p_recv_packet_buffer_length = recv_packet_len;
        p_ctx->tl.total_recv_length = 0;
        p_ctx->tl.chaining_error_count = 0;
        p_ctx->tl.master_chaining_error_count = 0;
        p_ctx->tl.transmission_completed = 0;
		p_ctx->tl.error_event = IFX_I2C_STACK_ERROR;
        status = ifx_i2c_tl_send_next_fragment(p_ctx);
    }while(FALSE);
    return status;
}


_STATIC_H host_lib_status_t ifx_i2c_tl_resend_packets(ifx_i2c_context_t *p_ctx)
{
    // Transport Layer must be idle
    if (p_ctx->tl.state != TL_STATE_IDLE)
    {
        return IFX_I2C_STACK_ERROR;
    }

    p_ctx->tl.packet_offset = 0; 
    p_ctx->tl.total_recv_length = 0;
    p_ctx->tl.state = TL_STATE_TX;
    return ifx_i2c_tl_send_next_fragment(p_ctx);
}

_STATIC_H uint8_t ifx_i2c_tl_calculate_pctr(const ifx_i2c_context_t *p_ctx)
{
    uint8_t pctr;
    uint16_t fragment_size = p_ctx->tl.max_packet_length;
    uint16_t remaining_data = p_ctx->tl.actual_packet_length - p_ctx->tl.packet_offset;
    // No chain
    if((p_ctx->tl.packet_offset==0)&&(remaining_data<=fragment_size))
    {
        pctr = TL_CHAINING_NO;
    }
    // First chain
    else if((p_ctx->tl.packet_offset==0)&&(remaining_data>fragment_size))
    {
        pctr = TL_CHAINING_FIRST;
    }
    // Intermediate chain
    else if((p_ctx->tl.packet_offset!=0)&&(remaining_data>fragment_size))
    {
        pctr = TL_CHAINING_INTERMEDIATE;
    }
    // Last chain
    else
    {
        pctr = TL_CHAINING_LAST;
    }
          
    return pctr;
}
_STATIC_H host_lib_status_t ifx_i2c_tl_send_next_fragment(ifx_i2c_context_t *p_ctx)
{
    uint8_t pctr = 0;
    // Calculate size of fragment (last one might be shorter)
    uint16_t tl_fragment_size = p_ctx->tl.max_packet_length;
    pctr = ifx_i2c_tl_calculate_pctr(p_ctx);
    if ((p_ctx->tl.actual_packet_length - p_ctx->tl.packet_offset)  <  tl_fragment_size)
    {
        tl_fragment_size = p_ctx->tl.actual_packet_length - p_ctx->tl.packet_offset;
    }

    // Assign the pctr 
    p_ctx->tx_frame_buffer[IFX_I2C_TL_HEADER_OFFSET] = pctr;
    //copy the data
    memcpy(p_ctx->tx_frame_buffer+IFX_I2C_TL_HEADER_OFFSET+1,p_ctx->tl.p_actual_packet + p_ctx->tl.packet_offset,tl_fragment_size);
    p_ctx->tl.packet_offset += tl_fragment_size;
    //send the fragment to dl layer
    return ifx_i2c_dl_send_frame(p_ctx,tl_fragment_size+1);
}

_STATIC_H host_lib_status_t ifx_i2c_tl_send_chaining_error(ifx_i2c_context_t *p_ctx)
{
    uint16_t tl_fragment_size = 1;
    p_ctx->tx_frame_buffer[IFX_I2C_TL_HEADER_OFFSET] = 0x07;
    p_ctx->tl.total_recv_length = 0;
    //send the fragment to dl layer
    return ifx_i2c_dl_send_frame(p_ctx,tl_fragment_size);
}

_STATIC_H host_lib_status_t ifx_i2c_tl_check_chaining_error(uint8_t current_chaning, uint8_t previous_chaining)
{
    host_lib_status_t status = IFX_I2C_STACK_ERROR;
    if(((current_chaning == TL_CHAINING_ERROR) || (current_chaning == TL_CHAINING_NO) || (current_chaning == TL_CHAINING_LAST) 
        || (current_chaning == TL_CHAINING_INTERMEDIATE) || (current_chaning == TL_CHAINING_FIRST)))
    {
        if((pctr_states_table[current_chaning][0] == previous_chaining) || (pctr_states_table[current_chaning][1] == previous_chaining))
        {
            status =  IFX_I2C_STACK_SUCCESS;
        }
    }

    return status;
}

_STATIC_H void ifx_i2c_dl_event_handler(ifx_i2c_context_t* p_ctx,host_lib_status_t event, const uint8_t* p_data, uint16_t data_len)
{
    uint8_t pctr = 0;
    uint8_t chaining = 0;
    uint8_t exit_machine = TRUE;
    do
    {
        if(NULL != p_data)
        {
            pctr = p_data[0];
            chaining = pctr & TL_PCTR_CHAIN_MASK;
        }
        // Propagate errors to upper layer
        if ((event & IFX_I2C_DL_EVENT_ERROR)||(pctr & TL_PCTR_CHANNEL_MASK))
        {
            p_ctx->tl.state = TL_STATE_ERROR;
			p_ctx->tl.error_event = IFX_I2C_STACK_ERROR;
        }
        switch(p_ctx->tl.state)
        {
            case TL_STATE_IDLE:
            {
                exit_machine = FALSE;
                p_ctx->tl.upper_layer_event_handler(p_ctx,IFX_I2C_STACK_SUCCESS, 0, 0);
            }
            break;
            case TL_STATE_TX:
            {
                // Frame transmission in Data Link layer complete, start receiving frames
                if (event & IFX_I2C_DL_EVENT_TX_SUCCESS)
                {
                    if (p_ctx->tl.packet_offset < p_ctx->tl.actual_packet_length)
                    {
                        // Transmission of one fragment complete, send next fragment
                        LOG_TL("[IFX-TL]: Tx:Fragment sent,now send next\n");  
                        // Chaining error from slave 
                        if(TL_CHAINING_ERROR == chaining)
                        {
                            LOG_TL("[IFX-TL]: Tx:Chaining error received while Tx\n");  
                            p_ctx->tl.state = TL_STATE_RESEND;
                            break;
                        }
                        // Any fragment received before complete transmission is error
                        if(data_len)
                        {
                            LOG_TL("[IFX-TL]: Tx:Data received while Tx\n");
                            p_ctx->tl.state = TL_STATE_ERROR;
                            break;
                        }
                        exit_machine = FALSE;
                        //lint --e{534} suppress "Return value is not required to be checked"
                        ifx_i2c_tl_send_next_fragment(p_ctx);
                    }
                    else
                    {
                        // Transmission of all fragments complete, start receiving fragments
                        LOG_TL("[IFX-TL]: Tx:All fragment sent\n");
                        p_ctx->tl.state = TL_STATE_RX;
                        p_ctx->tl.total_recv_length = 0;
                        p_ctx->tl.previous_chaining = TL_CHAINING_NO;
                        p_ctx->tl.transmission_completed = 1;
                        // if data is received after sending last frame
                        if (!(event & IFX_I2C_DL_EVENT_RX_SUCCESS))
                        {
                            LOG_TL("[IFX-TL]: Tx:Data already received after Tx\n");
                            // Received CTRL frame, trigger reception in Data Link layer
                            if (ifx_i2c_dl_receive_frame(p_ctx))
                            {
                                LOG_TL("[IFX-TL]: Tx:RX Received CTRL frame fail -> Inform UL\n");
                                p_ctx->tl.state = TL_STATE_ERROR;
                            }
                            exit_machine = FALSE;
                        }
                    }
                }
				else
				{
					LOG_TL("[IFX-TL]: Tx:IFX_I2C_DL_EVENT_TX_SUCCESS is not satisfied Tx\n");
					p_ctx->tl.state = TL_STATE_ERROR;
					break;				
				}
            }
            break;
            case TL_STATE_RX:           
            {
                // Reception of frame from Data Link layer
                if (event & IFX_I2C_DL_EVENT_RX_SUCCESS)
                {
                    // Message must contain at least the transport layer header
                    if (data_len < TL_HEADER_SIZE)
                    {
                        LOG_TL("[IFX-TL]: Rx : Data received is more than header len\n");
                        p_ctx->tl.state = TL_STATE_ERROR;
						break;
                    }

                    if(p_ctx->tl.error_event == IFX_I2C_STACK_MEM_ERROR)
                    {
                        if ((chaining == TL_CHAINING_LAST) || (ifx_i2c_dl_receive_frame(p_ctx)))
                        {
                            p_ctx->tl.state = TL_STATE_ERROR;
                            break;
                        }
                        p_ctx->tl.state = TL_STATE_RX;
                        exit_machine = FALSE;
                        break;
                    }

                    // If chaining error detected
                    if(IFX_I2C_STACK_SUCCESS != ifx_i2c_tl_check_chaining_error(chaining,p_ctx->tl.previous_chaining))
                    {
                        LOG_TL("[IFX-TL]: Rx : Chaining state is not correct\n");
                        p_ctx->tl.state = TL_STATE_RESEND;
                        break;
                    }
                    
                    p_ctx->tl.previous_chaining = chaining;
                    if(NULL == p_data)
                    {
                        p_ctx->tl.state = TL_STATE_ERROR;
                        break;
                    }

                    // No chaining and Last
                    if ((chaining == TL_CHAINING_NO)||(chaining == TL_CHAINING_LAST))
                    {
                        LOG_TL("[IFX-TL]: Rx : No chain/Last chain received, Inform UL\n");

                        exit_machine = FALSE;
                        // Copy frame payload to transport layer receive buffer
                        memcpy(p_ctx->tl.p_recv_packet_buffer + p_ctx->tl.total_recv_length, p_data + 1, data_len - 1);
                        p_ctx->tl.total_recv_length += (data_len - 1);
                        // Inform upper layer that a packet has arrived
                        p_ctx->tl.state = TL_STATE_IDLE;
                        *p_ctx->tl.p_recv_packet_buffer_length = p_ctx->tl.total_recv_length;
                        p_ctx->tl.upper_layer_event_handler(p_ctx,IFX_I2C_STACK_SUCCESS, p_ctx->tl.p_recv_packet_buffer, *p_ctx->tl.p_recv_packet_buffer_length);
                    }
                    else
                    {
                        p_ctx->tl.state = TL_STATE_CHAINING;
                    }
                }
				else
				{
					LOG_TL("[IFX-TL]: Tx:IFX_I2C_DL_EVENT_TX_SUCCESS is not satisfied Tx\n");
					p_ctx->tl.state = TL_STATE_ERROR;
					break;				
				}
            }
			break;

			case TL_STATE_CHAINING: 
			{					
                LOG_TL("[IFX-TL]: Chain : Chaining mode entered\n");
                // When receiving a starting fragment, fragment length must be max frame size for intermediate and last frame 
                // the buffer should not be empty
                if (data_len != (p_ctx->tl.max_packet_length+1))
                {
                    LOG_TL("[IFX-TL]: Chain : Data len not equal to max frame size\n");
                    p_ctx->tl.state = TL_STATE_CHAINING_ERROR;
                    break;
                }
                // Check for possible receive buffer overflow
                if ((p_ctx->tl.total_recv_length + data_len - 1) > (*p_ctx->tl.p_recv_packet_buffer_length))
                {
                    LOG_TL("[IFX-TL]: Chain : Buffer overflow\n");
					p_ctx->tl.error_event = IFX_I2C_STACK_MEM_ERROR;
					p_ctx->tl.state = TL_STATE_RX;
					break;
                }
                if(NULL == p_data)
                {
                    p_ctx->tl.state = TL_STATE_ERROR;
                    break;
                }                
                // Copy frame payload to transport layer receive buffer
                memcpy(p_ctx->tl.p_recv_packet_buffer + p_ctx->tl.total_recv_length, p_data + 1, data_len - 1);
                p_ctx->tl.total_recv_length += (data_len - 1);

                p_ctx->tl.previous_chaining = pctr;
                LOG_TL("[IFX-TL]: Chain : Continue  in receive mode\n");
                p_ctx->tl.state = TL_STATE_RX;
                // Continue receiving frames until packet is complete
                if (ifx_i2c_dl_receive_frame(p_ctx))
                {
                    p_ctx->tl.state = TL_STATE_ERROR;
                }
                exit_machine = FALSE;
            }
			break;

            case TL_STATE_RESEND:
            {
                LOG_TL("[IFX-TL]: Resend Enter\n");
                // In received mode , for wrong pctr with data
                if((data_len > 1) && (p_ctx->tl.transmission_completed == 1))
                {
                    LOG_TL("[IFX-TL]: Resend : Send chaining error\n");
                    p_ctx->tl.state = TL_STATE_CHAINING_ERROR;
                    break;
                }
                // Master Resend the packets,Resend only once, otherwise exit with error
                if(0 == (p_ctx->tl.chaining_error_count++))
                {  
                    LOG_TL("[IFX-TL]: Resend : Resending\n");
                    p_ctx->tl.state = TL_STATE_IDLE;
                    if(ifx_i2c_tl_resend_packets(p_ctx))
                    {
                        p_ctx->tl.state = TL_STATE_ERROR;
                    }
                    else
                    {
                        exit_machine = FALSE;
                    }
                }
                else
                {
                    LOG_TL("[IFX-TL]: Resend : chaining_error_count exceeded\n");
                    p_ctx->tl.state = TL_STATE_ERROR;
                }	
            }
            break;

            case TL_STATE_CHAINING_ERROR:
            {		
                // Send chaining error to slave
                p_ctx->tl.state = TL_STATE_TX;
                if(0 == (p_ctx->tl.master_chaining_error_count++))
                {
                    LOG_TL("[IFX-TL]: Chain error : Sending chain error\n");
                    // Send chaining error only once
                    if(ifx_i2c_tl_send_chaining_error(p_ctx))
                    {
                        p_ctx->tl.state = TL_STATE_ERROR;
                    }
                    else
                    {
                        exit_machine = FALSE;
                    }
                }
                else
                {
                    LOG_TL("[IFX-TL]: Chain error : master_chaining_error_count exceeded\n");
                    p_ctx->tl.state = TL_STATE_ERROR;
                }
            }
            break;
			case TL_STATE_ERROR:
			{
                LOG_TL("[IFX-TL]: Error\n");
                exit_machine = FALSE;
                if ((event & IFX_I2C_DL_EVENT_ERROR) || (data_len))
                {
                    p_ctx->tl.state = TL_STATE_IDLE;
                }
                p_ctx->tl.upper_layer_event_handler(p_ctx,p_ctx->tl.error_event, 0u, 0u);               
			}
            break;
            default:
				LOG_TL("[IFX-TL]: Exit from default case\n");
				p_ctx->tl.state = TL_STATE_IDLE;
				exit_machine = FALSE;
				p_ctx->tl.upper_layer_event_handler(p_ctx,p_ctx->tl.error_event, 0u, 0u);
                break;
        }
    }while(exit_machine);
}