serial.hpp

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// SPDX-License-Identifier: GPL-3.0-or-later
 
#pragma once
 
#include <mos/types.hpp>
 
typedef enum : u16
{
    OFFSET_INTERRUPT_ENABLE = 1,  // Interrupt Enable Register
    OFFSET_INTERRUPT_ID_FIFO = 2, // Interrupt ID Register and FIFO Control Register
    OFFSET_LINE_CONTROL = 3,      // Line Control Register
    OFFSET_MODEM_CONTROL = 4,     // Modem Control Register
    OFFSET_LINE_STATUS = 5,       // Line Status Register
    OFFSET_MODEM_STATUS = 6,      // Modem Status Register
    OFFSET_SCRATCH = 7,           // Scratch Register
 
    OFFSET_DLAB_DIVISOR_LSB = 0, // With DLAB set to 1, this is the least significant byte of the divisor value for setting the baud rate.
    OFFSET_DLAB_DIVISOR_MSB = 1, // With DLAB set to 1, this is the most significant byte of the divisor value.
} serial_register_t;
 
typedef enum
{
    CHAR_LENGTH_5 = 0x0,
    CHAR_LENGTH_6 = 0x1,
    CHAR_LENGTH_7 = 0x2,
    CHAR_LENGTH_8 = 0x3,
} serial_charlength_t;
 
typedef enum
{
    STOP_BITS_1,       // 1 stop bit
    STOP_BITS_15_OR_2, // 1.5 or 2 stop bits
} serial_stopbits_t;
 
typedef enum
{
    PARITY_NONE = 0,  // No parity
    PARITY_ODD = 1,   // Odd parity
    PARITY_EVEN = 2,  // Even parity
    PARITY_MARK = 3,  // Parity bit always 1
    PARITY_SPACE = 4, // Parity bit always 0
} serial_parity_t;
 
typedef enum
{
    INTERRUPT_DATA_AVAILABLE = 1 << 0,    // Data ready interrupt
    INTERRUPT_TRANSMITTER_EMPTY = 1 << 1, // Transmitter empty interrupt
    INTERRUPT_BREAK_ERROR = 1 << 2,       // Break error interrupt
    INTERRUPT_STATUS_CHANGE = 1 << 3,     // Status change interrupt
    INTERRUPT_NONE = 0,                   // No interrupts
    INTERRUPT_ALL = INTERRUPT_DATA_AVAILABLE | INTERRUPT_TRANSMITTER_EMPTY | INTERRUPT_BREAK_ERROR | INTERRUPT_STATUS_CHANGE,
} serial_interrupt_t;
 
typedef enum
{
    BAUD_RATE_115200 = 1,
    BAUD_RATE_57600 = 2,
    BAUD_RATE_38400 = 3,
    BAUD_RATE_19200 = 4,
    BAUD_RATE_9600 = 5,
    BAUD_RATE_4800 = 6,
    BAUD_RATE_2400 = 7,
    BAUD_RATE_1200 = 8,
    BAUD_RATE_600 = 9,
    BAUD_RATE_300 = 10,
    BAUD_RATE_110 = 11,
} serial_baudrate_t;
 
class ISerialDevice;
 
class ISerialDevice
{
  public:
    virtual ~ISerialDevice() = default;
 
    virtual u8 read_byte() = 0;
    virtual int write_byte(u8 byte) = 0;
    virtual bool get_data_ready() = 0;
    virtual u8 read_register(serial_register_t offset) = 0;
    virtual void write_register(serial_register_t offset, u8 value) = 0;
 
  public:
    bool setup();
    int read_data(char *data, size_t length);
    int write_data(const char *data, size_t length);
 
  protected:
    serial_baudrate_t baudrate_divisor;
    serial_charlength_t char_length;
    serial_stopbits_t stop_bits;
    serial_parity_t parity;
 
  private:
    typedef enum
    {
        MODEM_DCTS = 1 << 0, // Clear To Send input has changed since last read.
        MODEM_DDSR = 1 << 1, // Data Set Ready input has changed since last read.
        MODEM_TERI = 1 << 2, // Ring Indicator input has changed since last read.
        MODEM_DDCD = 1 << 3, // Data Carrier Detect input has changed since last read.
        MODEM_CLEAR_TO_SEND = 1 << 4,
        MODEM_DATA_SET_READY = 1 << 5,
        MODEM_RING_INDICATOR = 1 << 6,
        MODEM_DATA_CARRIER_DETECT = 1 << 7,
    } serial_modem_status_t;
 
    typedef enum
    {
        MODEM_DTR = 1 << 0,         // Data Terminal Ready
        MODEM_RTS = 1 << 1,         // Request To Send
        MODEM_UNUSED_PIN1 = 1 << 2, // Unused
        MODEM_IRQ = 1 << 3,         // Interrupt Request
        MODEM_LOOP = 1 << 4,        // Loopback
    } serial_modem_control_t;
 
    typedef enum
    {
        LINE_DATA_READY = 1 << 0,          // Data ready to be read.
        LINE_ERR_OVERRUN = 1 << 1,         // There has been data lost.
        LINE_ERR_PARITY = 1 << 2,          // Parity error.
        LINE_ERR_FRAMING = 1 << 3,         // Stop bit is missing.
        LINE_ERR_BREAK = 1 << 4,           // Break detected.
        LINE_TRANSMITR_BUF_EMPTY = 1 << 5, // (transmitter buffer is empty) Data can be sent.
        LINE_TRANSMITR_EMPTY = 1 << 6,     // Transmitter is not doing anything.
        LINE_ERR_IMPENDING = 1 << 7,       // There is an error with a word in the input buffer
    } serial_line_status_t;
 
    void SetBaudrateDivisor();
    void SetDataBits();
    void SetStopBits();
    void SetParity();
    void SetInterrupts(int interrupts);
    void SetModemOptions(serial_modem_control_t control, bool enable);
 
    char GetLineStatus();
    __maybe_unused char GetModelStatus();
    bool GetDataReady();
 
    void WaitReadyToRead();
    void WaitReadyToWrite();
};