serial.h

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/*
 * This file is part of Ninjaflight.
 *
 * Ninjaflight is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Ninjaflight is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Ninjaflight.  If not, see <http://www.gnu.org/licenses/>.
 */

/* 
 * Generic serial port interface abstraction layer
 */

#pragma once

typedef enum portMode_t {
    MODE_RX = 1 << 0,
    MODE_TX = 1 << 1,
    MODE_RXTX = MODE_RX | MODE_TX
} portMode_t;

typedef enum portOptions_t {
    SERIAL_NOT_INVERTED  = 0 << 0,
    SERIAL_INVERTED      = 1 << 0,
    SERIAL_STOPBITS_1    = 0 << 1,
    SERIAL_STOPBITS_2    = 1 << 1,
    SERIAL_PARITY_NO     = 0 << 2,
    SERIAL_PARITY_EVEN   = 1 << 2,
    SERIAL_UNIDIR        = 0 << 3,
    SERIAL_BIDIR         = 1 << 3
} portOptions_t;

typedef void (*serialReceiveCallbackPtr)(uint16_t data);   // used by serial drivers to return frames to app

typedef struct serialPort_s {
    const struct serial_port_ops *vTable;

    uint8_t identifier;
    portMode_t mode;
    portOptions_t options;

    uint32_t baudRate;

    uint32_t rxBufferSize;
    uint32_t txBufferSize;
    volatile uint8_t *rxBuffer;
    volatile uint8_t *txBuffer;
    uint32_t rxBufferHead;
    uint32_t rxBufferTail;
    uint32_t txBufferHead;
    uint32_t txBufferTail;

    // FIXME rename member to rxCallback
    serialReceiveCallbackPtr callback;
} serialPort_t;

struct serial_port_ops {
    void (*put)(serialPort_t *instance, uint8_t ch);

    uint8_t (*serialTotalRxWaiting)(serialPort_t *instance);
    uint8_t (*serialTotalTxFree)(serialPort_t *instance);

    uint8_t (*serialRead)(serialPort_t *instance);

    // Specified baud rate may not be allowed by an implementation, use serialGetBaudRate to determine actual baud rate in use.
    void (*serialSetBaudRate)(serialPort_t *instance, uint32_t baudRate);

    bool (*isSerialTransmitBufferEmpty)(serialPort_t *instance);

    void (*setMode)(serialPort_t *instance, portMode_t mode);

    void (*writeBuf)(serialPort_t *instance, void *data, int count);
    // Optional functions used to buffer large writes.
    void (*beginWrite)(serialPort_t *instance);
    void (*endWrite)(serialPort_t *instance);
};

void serialWrite(serialPort_t *instance, uint8_t ch);
uint8_t serialRxBytesWaiting(serialPort_t *instance);
uint8_t serialTxBytesFree(serialPort_t *instance);
void serialWriteBuf(serialPort_t *instance, uint8_t *data, int count);
uint8_t serialRead(serialPort_t *instance);
void serialSetBaudRate(serialPort_t *instance, uint32_t baudRate);
void serialSetMode(serialPort_t *instance, portMode_t mode);
bool isSerialTransmitBufferEmpty(serialPort_t *instance);
void serialPrint(serialPort_t *instance, const char *str);
uint32_t serialGetBaudRate(serialPort_t *instance);

// A shim that adapts the bufWriter API to the serialWriteBuf() API.
void serialWriteBufShim(void *instance, uint8_t *data, int count);
void serialBeginWrite(serialPort_t *instance);
void serialEndWrite(serialPort_t *instance);