1/* Copyright (c) 2013-2014 Jeffrey Pfau
  2 *
  3 * This Source Code Form is subject to the terms of the Mozilla Public
  4 * License, v. 2.0. If a copy of the MPL was not distributed with this
  5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
  6#include "gba-sio.h"
  7
  8#include "gba-io.h"
  9
 10const int GBASIOCyclesPerTransfer[4][MAX_GBAS] = {
 11	{ 31457, 62914, 94371, 125829 },
 12	{ 7864, 15728, 23592, 31457 },
 13	{ 5242, 10485, 15728, 20971 },
 14	{ 2621, 5242, 7864, 10485 }
 15};
 16
 17static struct GBASIODriver* _lookupDriver(struct GBASIO* sio, enum GBASIOMode mode) {
 18	switch (mode) {
 19	case SIO_NORMAL_8:
 20	case SIO_NORMAL_32:
 21		return sio->drivers.normal;
 22	case SIO_MULTI:
 23		return sio->drivers.multiplayer;
 24	case SIO_JOYBUS:
 25		return sio->drivers.joybus;
 26	default:
 27		return 0;
 28	}
 29}
 30
 31static void _switchMode(struct GBASIO* sio) {
 32	unsigned mode = ((sio->rcnt >> 14) & 0xC) | ((sio->siocnt >> 12) & 0x3);
 33	enum GBASIOMode oldMode = sio->mode;
 34	if (mode < 8) {
 35		sio->mode = (enum GBASIOMode) (mode & 0x3);
 36	} else {
 37		sio->mode = (enum GBASIOMode) (mode & 0xC);
 38	}
 39	if (oldMode != mode) {
 40		if (sio->activeDriver && sio->activeDriver->unload) {
 41			sio->activeDriver->unload(sio->activeDriver);
 42		}
 43		sio->activeDriver = _lookupDriver(sio, mode);
 44		if (sio->activeDriver && sio->activeDriver->load) {
 45			sio->activeDriver->load(sio->activeDriver);
 46		}
 47	}
 48}
 49
 50void GBASIOInit(struct GBASIO* sio) {
 51	sio->rcnt = RCNT_INITIAL;
 52	sio->siocnt = 0;
 53	sio->mode = -1;
 54	sio->activeDriver = 0;
 55	sio->drivers.normal = 0;
 56	sio->drivers.multiplayer = 0;
 57	sio->drivers.joybus = 0;
 58	_switchMode(sio);
 59}
 60
 61void GBASIODeinit(struct GBASIO* sio) {
 62	if (sio->drivers.multiplayer && sio->drivers.multiplayer->deinit) {
 63		sio->drivers.multiplayer->deinit(sio->drivers.multiplayer);
 64	}
 65	if (sio->drivers.joybus && sio->drivers.joybus->deinit) {
 66		sio->drivers.joybus->deinit(sio->drivers.joybus);
 67	}
 68}
 69
 70void GBASIOSetDriverSet(struct GBASIO* sio, struct GBASIODriverSet* drivers) {
 71	GBASIOSetDriver(sio, drivers->normal, SIO_NORMAL_8);
 72	GBASIOSetDriver(sio, drivers->multiplayer, SIO_MULTI);
 73	GBASIOSetDriver(sio, drivers->joybus, SIO_JOYBUS);
 74}
 75
 76void GBASIOSetDriver(struct GBASIO* sio, struct GBASIODriver* driver, enum GBASIOMode mode) {
 77	struct GBASIODriver** driverLoc;
 78	switch (mode) {
 79	case SIO_NORMAL_8:
 80	case SIO_NORMAL_32:
 81		driverLoc = &sio->drivers.normal;
 82		break;
 83	case SIO_MULTI:
 84		driverLoc = &sio->drivers.multiplayer;
 85		break;
 86	case SIO_JOYBUS:
 87		driverLoc = &sio->drivers.joybus;
 88		break;
 89	default:
 90		GBALog(sio->p, GBA_LOG_ERROR, "Setting an unsupported SIO driver: %x", mode);
 91		return;
 92	}
 93	if (*driverLoc) {
 94		if ((*driverLoc)->unload) {
 95			(*driverLoc)->unload(*driverLoc);
 96		}
 97		if ((*driverLoc)->deinit) {
 98			(*driverLoc)->deinit(*driverLoc);
 99		}
100	}
101	if (driver) {
102		driver->p = sio;
103
104		if (driver->init) {
105			if (!driver->init(driver)) {
106				driver->deinit(driver);
107				GBALog(sio->p, GBA_LOG_ERROR, "Could not initialize SIO driver");
108				return;
109			}
110		}
111		if (sio->mode == mode) {
112			sio->activeDriver = driver;
113			if (driver->load) {
114				driver->load(driver);
115			}
116		}
117	}
118	*driverLoc = driver;
119}
120
121void GBASIOWriteRCNT(struct GBASIO* sio, uint16_t value) {
122	sio->rcnt = value;
123	_switchMode(sio);
124	if (sio->activeDriver && sio->activeDriver->writeRegister) {
125		sio->activeDriver->writeRegister(sio->activeDriver, REG_RCNT, value);
126	}
127}
128
129void GBASIOWriteSIOCNT(struct GBASIO* sio, uint16_t value) {
130	if (sio->activeDriver && sio->activeDriver->writeRegister) {
131		value = sio->activeDriver->writeRegister(sio->activeDriver, REG_SIOCNT, value);
132	}
133	sio->siocnt = value;
134	_switchMode(sio);
135}
136
137void GBASIOWriteSIOMLT_SEND(struct GBASIO* sio, uint16_t value) {
138	if (sio->activeDriver && sio->activeDriver->writeRegister) {
139		sio->activeDriver->writeRegister(sio->activeDriver, REG_SIOMLT_SEND, value);
140	}
141}
142
143int32_t GBASIOProcessEvents(struct GBASIO* sio, int32_t cycles) {
144	if (sio->activeDriver && sio->activeDriver->processEvents) {
145		return sio->activeDriver->processEvents(sio->activeDriver, cycles);
146	}
147	return INT_MAX;
148}