longfi.c

#include "board.h"
#include "longfiP.h"
#include <string.h>

uint16_t BufferSize = BUFFER_SIZE;
uint8_t  Buffer[BUFFER_SIZE];

int16_t RssiValue = 0;
int8_t  SnrValue  = 0;

static LongFiInternal_t internal;

LongFi_t
longfi_new_handle(BoardBindings_t *         bindings,
                  Radio_t *                 radio,
                  LongFiConfig_t            config,
                  union LongFiAuthCallbacks auth_cb_set)
{
    LongFi_t handle = {.radio    = radio,
                       .config   = config,
                       .bindings = bindings,
                       .auth_cb  = auth_cb_set,
                       .lfc      = {
                           .seq = 0,
                           .cfg =
                               {
                                   .cb_data = NULL,
                                   .oui     = config.oui,
                                   .did     = config.device_id,
                                   .key     = auth_cb_set.preshared_key,
                                   .key_len = 16,
                               },
                       }};
    return handle;
}

void
longfi_init(LongFi_t * handle)
{
    // store pointer to internal context for callback definitions
    bindings = handle->bindings;

    switch
        LORA_SPREADING_FACTOR
        {
        case 10:
            internal.spreading_factor = 3;
            break;
        case 9:
            internal.spreading_factor = 2;
            break;
        case 8:
            internal.spreading_factor = 1;
            break;
        case 7:
            internal.spreading_factor = 0;
            break;
        default:
            internal.spreading_factor = 2;
        }

    // configure sx1276 radio events with local helium functions
    internal.radio_events.TxDone    = OnTxDone;
    internal.radio_events.RxDone    = OnRxDone;
    internal.radio_events.TxTimeout = OnTxTimeout;
    internal.radio_events.RxTimeout = OnRxTimeout;
    internal.radio_events.RxError   = OnRxError;

    // this function calls TimerInits and handle->radio->IoIrqInit, which are
    // implemented here
    handle->radio->Init(&internal.radio_events);

    // sleep the radio and wait for a send or receive call
    handle->radio->Sleep();
}

void
longfi_set_buf(LongFi_t * handle, uint8_t * buffer, size_t buffer_len)
{
    internal.buffer     = buffer;
    internal.buffer_len = (buffer != NULL) ? buffer_len : 0;
}

void
longfi_rx(LongFi_t * handle)
{
    handle->radio->Rx(0);
}

#define MIN(x, y)                                                              \
    ({                                                                         \
        typeof(x) _x = (x);                                                    \
        typeof(y) _y = (y);                                                    \
        (void)(&_x == &_y);                                                    \
        _x < _y ? _x : _y;                                                     \
    })

// number of bytes in a fragment
size_t
payload_bytes_in_single_fragment_packet()
{
    return payload_per_fragment[internal.spreading_factor]
           - sizeof(packet_header_t);
}

// number of bytes in a fragment
size_t
payload_bytes_in_first_fragment_of_many()
{
    return payload_per_fragment[internal.spreading_factor]
           - sizeof(packet_header_multiple_fragments_t);
}

// number of bytes in a fragment
size_t
payload_bytes_in_subsequent_fragments()
{
    return payload_per_fragment[internal.spreading_factor]
           - sizeof(fragment_header_t);
}

void
longfi_rf_test(LongFi_t * handle)
{
    uint8_t dummy_data = 0xAB;
    handle->radio->SetTxConfig(MODEM_LORA,
                               TX_OUTPUT_POWER,
                               0,
                               LORA_BANDWIDTH,
                               LORA_SPREADING_FACTOR,
                               LORA_CODINGRATE,
                               LORA_PREAMBLE_LENGTH,
                               LORA_FIX_LENGTH_PAYLOAD_ON,
                               true,
                               0,
                               0,
                               LORA_IQ_INVERSION_ON,
                               3000);
    handle->radio->SetChannel(910000000);
    handle->radio->Send(&dummy_data, (uint8_t)sizeof(dummy_data));
}

uint32_t
longfi_get_random(LongFi_t * handle)
{
    return handle->radio->Random();
}

void
_send_random(LongFi_t * handle, uint8_t * data, size_t len)
{
    uint32_t frequency;
    // bool     free_to_transmit = false;
    // while (!free_to_transmit)
    // {
    uint32_t random = (*bindings->get_random_bits)(4);
    frequency       = uplink_channel_map[random % LONGFI_NUM_UPLINK_CHANNELS];
    // free_to_transmit =
    //     handle->radio->IsChannelFree(MODEM_LORA, frequency, -65, 0);
    // }
    handle->radio->SetTxConfig(MODEM_LORA,
                               TX_OUTPUT_POWER,
                               0,
                               LORA_BANDWIDTH,
                               LORA_SPREADING_FACTOR,
                               LORA_CODINGRATE,
                               LORA_PREAMBLE_LENGTH,
                               LORA_FIX_LENGTH_PAYLOAD_ON,
                               true,
                               0,
                               0,
                               LORA_IQ_INVERSION_ON,
                               3000);
    handle->radio->SetChannel(frequency);
    handle->radio->Send(data, len);
}

#include <stdio.h>

void
longfi_send(LongFi_t * handle, const uint8_t * data, size_t len)
{
    size_t output_length = BUFFER_SIZE;
    lfc_transmit(&handle->lfc, data, len, &Buffer[0], &output_length);
    internal.tx_len = output_length;
    internal.tx_cnt = output_length;
    _send_random(handle, Buffer, output_length);
}

RxPacket_t
longfi_get_rx(__attribute__((unused)) LongFi_t * handle)
{
    RxPacket_t rx = {
        .buf  = internal.buffer,
        .len  = internal.rx_len,
        .rssi = RssiValue,
        .snr  = SnrValue,
    };
    internal.buffer     = NULL;
    internal.buffer_len = 0;
    return rx;
}

ClientEvent_t
longfi_handle_event(LongFi_t * handle, RfEvent_t event)
{
    internal.cur_event = InternalEvent_None;

    switch (event)
    {
    case RFE_DIO0:
        (*(internal.dio_irq_handles[0]))();
        break;
    case RFE_DIO1:
        // SX126x library only has the one handle, so fire it even fore DIO1
        (*(internal.dio_irq_handles[0]))();
        break;
    case RFE_DIO2:
        (*internal.dio_irq_handles[2])();
        break;
    case RFE_DIO3:
        (*internal.dio_irq_handles[3])();
        break;
    case RFE_DIO4:
        (*internal.dio_irq_handles[4])();
        break;
    case RFE_DIO5:
        (*internal.dio_irq_handles[5])();
        break;
    case RFE_Timer1:
        // TODO: needs to dispatch the callback stashed from TimerInit
        break;
    case RFE_Timer2:
        // TODO: needs to dispatch the callback stashed from TimerInit
        break;
    case RFE_Timer3:
        // TODO: needs to dispatch the callback stashed from TimerInit
        break;
    default:
        break;
    }

    return _handle_internal_event(handle);
}

ClientEvent_t
_handle_internal_event(LongFi_t * handle)
{
    switch (internal.cur_event)
    {
    case InternalEvent_None:
        return ClientEvent_None;
        break;
    case InternalEvent_TxDone:
        // if all the tx data is sent, we're done!
        if (internal.tx_len == internal.tx_cnt)
        {
            // sleep when done transmitting
            handle->radio->Sleep();
            return ClientEvent_TxDone;
        }
        // else we are sending another fragment
        else
        {
            uint8_t len = MIN(payload_per_fragment[internal.spreading_factor],
                              internal.tx_len - internal.tx_cnt);
            _send_random(handle, &Buffer[internal.tx_cnt], len);
            internal.tx_cnt += len;
            return ClientEvent_None;
        }
        break;
    case InternalEvent_RxDone:
        // could trigger pending Tx'es here
        return ClientEvent_Rx;
        break;
    case InternalEvent_TxTimeout:
        // potential internal retry logic
        break;
    case InternalEvent_RxTimeout:
        // potential internal retry logic
        break;
    case InternalEvent_RxError:
        // potential internal retry logic
        break;
    default:
        break;
    }
    return ClientEvent_None;
}

// each sx12xx board definition must invoke this
void
IoIrqInit(IrqHandler * irq_handlers[NUM_IRQ_HANDLES])
{
    for (uint32_t i = 0; i < NUM_IRQ_HANDLES; i++)
    {
        internal.dio_irq_handles[i] = irq_handlers[i];
    }
}

void
OnTxDone(void)
{
    internal.cur_event = InternalEvent_TxDone;
}

void
OnRxDone(uint8_t * payload, uint16_t size, int16_t rssi, int8_t snr)
{
    internal.cur_event = InternalEvent_RxDone;
    uint8_t rx_len     = (uint8_t)MIN((size_t)size, internal.buffer_len);
    internal.rx_len    = rx_len;
    memmove(internal.buffer, payload, rx_len);
    RssiValue = rssi;
    SnrValue  = snr;
}

void
OnTxTimeout(void)
{
    internal.cur_event = InternalEvent_TxTimeout;
}

void
OnRxTimeout(void)
{
    internal.cur_event = InternalEvent_RxTimeout;
}

void
OnRxError(void)
{
    internal.cur_event = InternalEvent_RxTimeout;
}