Duckstation/src/core/pad.h
Connor McLaughlin 845cd37835 DMA: Determine slice size based on whether pad is transmitting
Plenty of games seem to suffer from this issue where they have
a linked list DMA going while polling the controller. Using a
too-large slice size will result in the serial timing being off,
and the game thinking the controller is disconnected. So we
don't hurt performance too much for the general case, we reduce
this to equal CPU and DMA time when the controller is
transferring, but otherwise leave it at the higher size.
2021-01-06 00:15:42 +10:00

130 lines
3.3 KiB
C++

#pragma once
#include "common/bitfield.h"
#include "common/fifo_queue.h"
#include "types.h"
#include <array>
#include <memory>
class StateWrapper;
class TimingEvent;
class Controller;
class MemoryCard;
class Pad final
{
public:
Pad();
~Pad();
void Initialize();
void Shutdown();
void Reset();
bool DoState(StateWrapper& sw);
Controller* GetController(u32 slot) const { return m_controllers[slot].get(); }
void SetController(u32 slot, std::unique_ptr<Controller> dev);
MemoryCard* GetMemoryCard(u32 slot) { return m_memory_cards[slot].get(); }
void SetMemoryCard(u32 slot, std::unique_ptr<MemoryCard> dev);
u32 ReadRegister(u32 offset);
void WriteRegister(u32 offset, u32 value);
ALWAYS_INLINE bool IsTransmitting() const { return m_state != State::Idle; }
private:
static constexpr u32 NUM_SLOTS = 2;
enum class State : u32
{
Idle,
Transmitting,
WaitingForACK
};
enum class ActiveDevice : u8
{
None,
Controller,
MemoryCard
};
union JOY_CTRL
{
u16 bits;
BitField<u16, bool, 0, 1> TXEN;
BitField<u16, bool, 1, 1> SELECT;
BitField<u16, bool, 2, 1> RXEN;
BitField<u16, bool, 4, 1> ACK;
BitField<u16, bool, 6, 1> RESET;
BitField<u16, u8, 8, 2> RXIMODE;
BitField<u16, bool, 10, 1> TXINTEN;
BitField<u16, bool, 11, 1> RXINTEN;
BitField<u16, bool, 12, 1> ACKINTEN;
BitField<u16, u8, 13, 1> SLOT;
};
union JOY_STAT
{
u32 bits;
BitField<u32, bool, 0, 1> TXRDY;
BitField<u32, bool, 1, 1> RXFIFONEMPTY;
BitField<u32, bool, 2, 1> TXDONE;
BitField<u32, bool, 7, 1> ACKINPUT;
BitField<u32, bool, 9, 1> INTR;
BitField<u32, u32, 11, 21> TMR;
};
union JOY_MODE
{
u16 bits;
BitField<u16, u8, 0, 2> reload_factor;
BitField<u16, u8, 2, 2> character_length;
BitField<u16, bool, 4, 1> parity_enable;
BitField<u16, u8, 5, 1> parity_type;
BitField<u16, u8, 8, 1> clk_polarity;
};
ALWAYS_INLINE bool CanTransfer() const { return m_transmit_buffer_full && m_JOY_CTRL.SELECT && m_JOY_CTRL.TXEN; }
ALWAYS_INLINE TickCount GetTransferTicks() const { return static_cast<TickCount>(ZeroExtend32(m_JOY_BAUD) * 8); }
// From @JaCzekanski
// ACK lasts ~96 ticks or approximately 2.84us at master clock (not implemented).
// ACK delay is between 6.8us-13.7us, or ~338 ticks at master clock for approximately 9.98us.
// Memory card responds faster, approximately 5us or ~170 ticks.
static constexpr TickCount GetACKTicks(bool memory_card) { return memory_card ? 170 : 450; }
void SoftReset();
void UpdateJoyStat();
void TransferEvent(TickCount ticks_late);
void BeginTransfer();
void DoTransfer(TickCount ticks_late);
void DoACK();
void EndTransfer();
void ResetDeviceTransferState();
std::array<std::unique_ptr<Controller>, NUM_SLOTS> m_controllers;
std::array<std::unique_ptr<MemoryCard>, NUM_SLOTS> m_memory_cards;
std::unique_ptr<TimingEvent> m_transfer_event;
State m_state = State::Idle;
JOY_CTRL m_JOY_CTRL = {};
JOY_STAT m_JOY_STAT = {};
JOY_MODE m_JOY_MODE = {};
u16 m_JOY_BAUD = 0;
ActiveDevice m_active_device = ActiveDevice::None;
u8 m_receive_buffer = 0;
u8 m_transmit_buffer = 0;
u8 m_transmit_value = 0;
bool m_receive_buffer_full = false;
bool m_transmit_buffer_full = false;
};
extern Pad g_pad;