uart/hardware0.hpp

#ifndef UART_HARDWARE_0_HPP
#define UART_HARDWARE_0_HPP

#include <stdint.h>

#include <avr/interrupt.h>
#include <avr/io.h>
#include <avr/sfr_defs.h>

#include "config.hpp"
#include "hardware.hpp"

#define FORCE_INLINE __attribute__((always_inline))

namespace uart {

namespace detail {

#if defined(__AVR_ATmega1284P__) || defined(__AVR_ATmega328P__)

/*
The following works in avr-gcc 5.4.0, but is not legal C++, because ptr's are not legal constexpr's:
  constexpr auto *foo = ptr;

Workaround is to store the the address of the ptr in a uintptr_t and reinterpret_cast it at call site.
The _SFR_ADDR macro in sfr_defs.h would give the address, but it does that by taking the address of the dereferenced
pointer and casts it to uint16_t, which is still not a legal constexpr.
The workaround therefore is to disable the pointer cast and dereference macro _MMIO_BYTE temporarily.
*/

#pragma push_macro("_MMIO_BYTE")
#undef _MMIO_BYTE
#define _MMIO_BYTE

struct Registers0 {
	static constexpr uintptr_t IO_REG_ADDR = UDR0;
	static constexpr uintptr_t CTRL_STAT_REG_A_ADDR = UCSR0A;
	static constexpr uintptr_t CTRL_STAT_REG_B_ADDR = UCSR0B;
	static constexpr uintptr_t CTRL_STAT_REG_C_ADDR = UCSR0C;
	static constexpr uintptr_t BAUD_REG_L_ADDR = UBRR0L;
	static constexpr uintptr_t BAUD_REG_H_ADDR = UBRR0H;
};

#pragma pop_macro("_MMIO_BYTE")

enum class ControlFlagsA0 {
	MULTI_PROC_COMM_MODE = MPCM0,
	SPEED_2X = U2X0,
	PARITY_ERROR = UPE0,
	DATA_OVER_RUN = DOR0,
	FRAME_ERROR = FE0,
	DATA_REG_EMPTY = UDRE0,
	TRANSMIT_COMPLETE = TXC0,
	RECEIVE_COMPLETE = RXC0,
};

enum class ControlFlagsB0 {
	TX_DATA_BIT_8 = TXB80,
	RX_DATA_BIT_8 = RXB80,
	CHAR_SIZE_2 = UCSZ02,
	TX_ENABLE = TXEN0,
	RX_ENABLE = RXEN0,
	DATA_REG_EMPTY_INT_ENABLE = UDRIE0,
	TX_INT_ENABLE = TXCIE0,
	RX_INT_ENABLE = RXCIE0,
};

enum class ControlFlagsC0 {
	CLK_POLARITY = UCPOL0,
	CHAR_SIZE_0 = UCSZ00,
	CHAR_SIZE_1 = UCSZ01,
	STOP_BIT_SEL = USBS0,
	PARITY_MODE_0 = UPM00,
	PARITY_MODE_1 = UPM01,
	MODE_SEL_0 = UMSEL00,
	MODE_SEL_1 = UMSEL01,
};

// clang-format off
constexpr int operator<<(const int &lhs, const ControlFlagsA0 &rhs) { return lhs << static_cast<int>(rhs); }
constexpr int operator<<(const int &lhs, const ControlFlagsB0 &rhs) { return lhs << static_cast<int>(rhs); }
constexpr int operator<<(const int &lhs, const ControlFlagsC0 &rhs) { return lhs << static_cast<int>(rhs); }
// clang-format on

extern void (*fnRx0IntHandler)();
extern void (*fnDataReg0EmptyIntHandler)();

#else
#error "This chip is not supported"
#endif

} // namespace detail

template <class cfg = Config<>, Driven driven = Driven::INTERRUPT, Mode mode = Mode::ASYNCHRONOUS>
class Hardware0 : public detail::BlockingHardware<detail::Registers0, detail::ControlFlagsA0, detail::ControlFlagsB0,
                                                  detail::ControlFlagsC0, cfg, mode> {
};

template <class cfg, Mode mode>
class Hardware0<cfg, Driven::INTERRUPT, mode>
    : public detail::InterruptHardware<detail::Registers0, detail::ControlFlagsA0, detail::ControlFlagsB0,
                                       detail::ControlFlagsC0, cfg, mode> {
	using detail::InterruptHardware<detail::Registers0, detail::ControlFlagsA0, detail::ControlFlagsB0,
	                                detail::ControlFlagsC0, cfg, mode>::rxIntHandler;

	using detail::InterruptHardware<detail::Registers0, detail::ControlFlagsA0, detail::ControlFlagsB0,
	                                detail::ControlFlagsC0, cfg, mode>::dataRegEmptyIntHandler;

	using HardwareImpl = detail::Hardware<detail::Registers0, detail::ControlFlagsA0, detail::ControlFlagsB0,
	                                      detail::ControlFlagsC0, cfg, Driven::INTERRUPT, mode>;

  public:
	static void init() FORCE_INLINE
	{
		detail::fnRx0IntHandler = rxIntHandler;
		detail::fnDataReg0EmptyIntHandler = dataRegEmptyIntHandler;

		HardwareImpl::init();
		sei();
	}
};

} // namespace uart

#undef FORCE_INLINE

#endif

//////////////////////////////////////////////////////////////////////////

#ifdef UART0_INT_VECTORS

#include <avr/interrupt.h>

namespace uart {
namespace detail {

#if defined(__AVR_ATmega1284P__) || defined(__AVR_ATmega328P__)

#if defined(__AVR_ATmega328P__)
#define USART0_RX_vect USART_RX_vect
#define USART0_UDRE_vect USART_UDRE_vect
#endif

void (*fnRx0IntHandler)() = nullptr;
void (*fnDataReg0EmptyIntHandler)() = nullptr;

ISR(USART0_RX_vect)
{
	if (fnRx0IntHandler)
		fnRx0IntHandler();
}

ISR(USART0_UDRE_vect)
{
	if (fnDataReg0EmptyIntHandler)
		fnDataReg0EmptyIntHandler();
}

#else
#error "This chip is not supported"
#endif

} // namespace detail
} // namespace uart

#undef UART0_INT_VECTORS

#endif