/*
 * Copyright 2021, Haiku, Inc. All rights reserved.
 * Distributed under the terms of the MIT License.
 */


#include <arch/riscv64/arch_uart_sifive.h>
#include <new>


ArchUARTSifive::ArchUARTSifive(addr_t base, int64 clock)
        :
        DebugUART(base, clock)
{
}


ArchUARTSifive::~ArchUARTSifive()
{
}


void
ArchUARTSifive::InitEarly()
{
        //Regs()->ie = 0;
        //Enable();
}


void
ArchUARTSifive::Init()
{
}


void
ArchUARTSifive::InitPort(uint32 baud)
{
        int64 clock = Clock();

        // if we get an invalid clock for some reason, just accept the currently set baud.
        if (clock < 0)
                return;

        uint64 quotient = (clock + baud - 1) / baud;

        if (quotient == 0)
                Regs()->div = 0;
        else
                Regs()->div = (uint32)(quotient - 1);
}


void
ArchUARTSifive::Enable()
{
        //Regs()->txctrl.enable = 1;
        //Regs()->rxctrl.enable = 1;
        DebugUART::Enable();
}


void
ArchUARTSifive::Disable()
{
        //Regs()->txctrl.enable = 0;
        //Regs()->rxctrl.enable = 0;
        DebugUART::Disable();
}


int
ArchUARTSifive::PutChar(char ch)
{
        // TODO: Needs to be more atomic?
        // Character drop will happen if there is one space left
        // in the FIFO and two harts race. atomic_fetch_or of
        // register, retrying if isFull.
        while (Regs()->txdata.isFull) {}
        Regs()->txdata.val = ch;
        return 0;
}


int
ArchUARTSifive::GetChar(bool wait)
{
        UARTSifiveRegs::Rxdata data;
        do {
                data.val = Regs()->rxdata.val;
        } while (!wait || data.isEmpty);

        return data.isEmpty ? -1 : data.data;
}


void
ArchUARTSifive::FlushTx()
{
}


void
ArchUARTSifive::FlushRx()
{
}


void
ArchUARTSifive::Barrier()
{
        asm volatile ("" : : : "memory");
}


ArchUARTSifive*
arch_get_uart_sifive(addr_t base, int64 clock)
{
        static char buffer[sizeof(ArchUARTSifive)];
        ArchUARTSifive* uart = new(buffer) ArchUARTSifive(base, clock);
        return uart;
}