quack/main/adb.c

/*
 *  adb.c
 *  quack
 *
 *  Created by Michel DEPEIGE on 7/01/2020.
 *  Copyright (c) 2020 Michel DEPEIGE.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program (see the file COPYING); if not, write to the
 * Free Software Foundation, Inc.,
 * 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA
 *
 */

#include <stdio.h>
#include "driver/gpio.h"
#include "sdkconfig.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_log.h"
#include "esp_system.h"
#include "esp_spi_flash.h"
#include "driver/rmt.h"

#include "adb.h"
#include "led.h"
#include "gpio.h"

/* globals */
rmt_config_t adb_rmt_rx = RMT_DEFAULT_CONFIG_RX(GPIO_ADB, RMT_RX_CHANNEL);
extern TaskHandle_t t_green, t_blue, t_yellow, t_red;
extern TaskHandle_t t_click, t_qx, t_qy;

/* static defines */
static void	adb_handle_button(bool action);
static bool	adb_rx_isone(rmt_item32_t cell);
static bool	adb_rx_isstop(rmt_item32_t cell);
static bool	adb_rx_iszero(rmt_item32_t cell);
static uint16_t	IRAM_ATTR adb_rx_mouse();
static void	adb_rx_setup(void);
static bool	adb_rx_tlt(void);
static void	adb_tx_as(void);
static void	adb_tx_one(void);
static void	adb_tx_setup(void);
static void	adb_tx_zero(void);

/* functions */
static void	adb_handle_button(bool action) {
	static bool	status = ADB_B_UP;	// Keep state. Click is active low

	if (status == ADB_B_UP && action == ADB_B_UP)
		return ;
	if (status == ADB_B_DOWN && action == ADB_B_DOWN)
		return ;

	/* release button */
	if (status == ADB_B_DOWN && action == ADB_B_UP) {
		xTaskNotify(t_click, 0, eSetValueWithOverwrite);
		status = ADB_B_UP;
		ESP_LOGD("ADB", "button released");
		return ;
	}

	/* press button */
	if (status == ADB_B_UP && action == ADB_B_DOWN) {
		xTaskNotify(t_click, 1, eSetValueWithOverwrite);
		status = ADB_B_DOWN;
		ESP_LOGD("ADB", "button pressed");
		return ;
	}
}

void	adb_init(void) {
	/* initialise */
	gpio_set_level(GPIO_ADB, 1);
	adb_tx_reset();

	/* avoir console flood when installing/uninstalling RMT driver */
	esp_log_level_set("intr_alloc", ESP_LOG_INFO);

	/* init RMT RX driver with default values for ADB  */
	adb_rmt_rx.rx_config.filter_en = true;
	adb_rmt_rx.rx_config.filter_ticks_thresh = 10;
	adb_rmt_rx.rx_config.idle_threshold = 100;
	rmt_config(&adb_rmt_rx);

	/* If jumper is set, switch to ADB host mode */
	if (gpio_get_level(GPIO_ADBSRC) == 0)
		xTaskCreatePinnedToCore(adb_task_host, "ADB_HOST", 6 * 1024, NULL, tskADB_PRIORITY, NULL, 1);
	else
		xTaskCreatePinnedToCore(adb_task_mouse, "ADB_MOUSE", 6 * 1024, NULL, tskADB_PRIORITY, NULL, 1);
}

void	adb_task_host(void *pvParameters) {
	/* Classic Apple Mouse Protocol is 16 bits long */
	uint16_t	data;
	int8_t		move = 0;

	/* put green led to steady if BT is disabled. Otherwise BT init will do it */
	if (gpio_get_level(GPIO_BTOFF) == 0)
		xTaskNotify(t_green, LED_ON, eSetValueWithOverwrite);
	ESP_LOGI("ADB", "host started");

	/* poll the mouse like a maniac. It will answer only if there is user input */
	ESP_ERROR_CHECK(rmt_driver_install(RMT_RX_CHANNEL, 200, 0));

	while (true) {
		/* Should give us a polling rate between 80-90 Hz */
		vTaskDelay(7 / portTICK_PERIOD_MS);
		adb_tx_cmd(ADB_MOUSE|ADB_TALK|ADB_REG0);
		data = adb_rx_mouse();

		if (data) {
			/* click is active low */
			if (! (data & ADB_CMP_B1) || (! (data & ADB_CMP_B2)))
				adb_handle_button(ADB_B_DOWN);
			else
				adb_handle_button(ADB_B_UP);

			/* cast negative signed 7 bits to signed 8 bits */
			move = (data & ADB_CMD_MX) >> 0;
			if (move & 0x40) {
				move &= ~0x40;
				move |= 0x80;
				move += 64;
			}

			if (move)
				xTaskNotify(t_qx, move, eSetValueWithOverwrite);

			move = (data & ADB_CMD_MY) >> 8;
			if (move & 0x40) {
				move &= ~0x40;
				move |= 0x80;
				move += 64;
			}

			if (move)
				xTaskNotify(t_qy, move, eSetValueWithOverwrite);
		}
	}
}

void	adb_task_mouse(void *pvParameters) {
	ESP_LOGI("ADB", "ADB mouse started");
	vTaskSuspend(NULL);
}

/*
 * some ADB mouses are using cells as short as 24µs+49µs, try to get that...
 * spec allow ±30% variance
 *
 * units are in µs
 */

static bool adb_rx_isone(rmt_item32_t cell) {
	if (cell.level0 == 0 && (cell.duration0 >= 22 && cell.duration0 <= 44) &&
		cell.level1 == 1 && (cell.duration1 >= 46 && cell.duration1 <= 86))
		return true;
	return false;
}

static bool adb_rx_isstop(rmt_item32_t cell) {
	/* high part of the well is lengh 0 because of RMT timeout (100µs+) */
	if (cell.level0 == 0 && (cell.duration0 >= 46 && cell.duration0 <= 86) &&
		cell.level1 == 1 && cell.duration1 == 0)
		return true;
	return false;
}

static bool adb_rx_iszero(rmt_item32_t cell) {
	if (cell.level0 == 0 && (cell.duration0 >= 46 && cell.duration0 <= 86) &&
		cell.level1 == 1 && (cell.duration1 >= 22 && cell.duration1 <= 44))
		return true;
	return false;
}

static uint16_t	IRAM_ATTR adb_rx_mouse() {
	uint16_t data = 0;
	RingbufHandle_t rb = NULL;
	rmt_item32_t* items = NULL;
	size_t rx_size = 0;
	size_t i;

	rmt_get_ringbuf_handle(RMT_RX_CHANNEL, &rb);
	assert(rb != NULL);
	rmt_rx_start(RMT_RX_CHANNEL, true);
	items = (rmt_item32_t*)xRingbufferReceive(rb, &rx_size, pdMS_TO_TICKS(8));
	rmt_rx_stop(RMT_RX_CHANNEL);

	if (items == NULL)
		return 0;

	/*
 	 * Mouse response size in bits is events / sizeof(rmt_item32_t) (4)
	 * start bit + 16 data bits + stop bit = 72 bytes in RMT buffer (18 bits received)
	 *
	 * Check start / stop bits and size.
	 * On real Macintoshes, ADB Manager does something similar
	 */

	switch (rx_size) {
		case 0:
			return 0;
		case 72:
			xTaskNotify(t_yellow, LED_ONCE, eSetValueWithOverwrite);
			break;
		default:
			ESP_LOGD("ADB", "wrong size of %i bit(s)", rx_size / sizeof(rmt_item32_t));
			xTaskNotify(t_red, LED_ONCE, eSetValueWithOverwrite);
	}

	/* check start and stop bits */
	if (! adb_rx_isone(*(items+0)) && (! adb_rx_isstop(*(items+(rx_size / sizeof(rmt_item32_t) - 1))))) {
		xTaskNotify(t_red, LED_ONCE, eSetValueWithOverwrite);
		return 0;
	}

	/* rebuild our data with RMT buffer */
	for (i = 1; i < ((rx_size / sizeof(rmt_item32_t)) - 1); i++) {
		data <<= 1;

		/* check that every data is either one or zero */
		if ((! adb_rx_isone(*(items+i))) && (! adb_rx_iszero(*(items+i)))) {
			xTaskNotify(t_red, LED_ONCE, eSetValueWithOverwrite);
			return 0;
		}

		if (adb_rx_isone(*(items+i)))
			data |= 1;
		//printf("%d:%dus %d:%dus ", (items+i)->level0, (items+i)->duration0, (items+i)->level1, (items+i)->duration1);
	}
	//printf("\n");
	vRingbufferReturnItem(rb, (void*) items);

	return data;
}

static inline void	adb_rx_setup() {
	gpio_set_level(GPIO_DIR, 0);
	gpio_set_direction(GPIO_ADB, GPIO_MODE_INPUT);
	gpio_pullup_dis(GPIO_ADB);
	gpio_pulldown_dis(GPIO_ADB);
}

static inline void	adb_tx_as() {
	/* send attention (800 µs low) + sync (70 µs high) */
	gpio_set_level(GPIO_ADB, 0);
	ets_delay_us(800-1);
	gpio_set_level(GPIO_ADB, 1);
	ets_delay_us(80-1);
}

void	adb_tx_cmd(unsigned char cmd) {
	adb_tx_setup();
	adb_tx_as();

	/* send actual byte (unrolled loop) */
	cmd & 0x80 ? adb_tx_one() : adb_tx_zero();
	cmd & 0x40 ? adb_tx_one() : adb_tx_zero();
	cmd & 0x20 ? adb_tx_one() : adb_tx_zero();
	cmd & 0x10 ? adb_tx_one() : adb_tx_zero();
	cmd & 0x08 ? adb_tx_one() : adb_tx_zero();
	cmd & 0x04 ? adb_tx_one() : adb_tx_zero();
	cmd & 0x02 ? adb_tx_one() : adb_tx_zero();
	cmd & 0x01 ? adb_tx_one() : adb_tx_zero();

	/* stop bit */
	adb_tx_zero();
	adb_rx_setup();
}

static inline void	adb_tx_one() {
	/* values from AN591 Datasheet minus the estimated call to ets_delay_us */
	gpio_set_level(GPIO_ADB, 0);
	ets_delay_us(ADB_1_LOW - 1);
	gpio_set_level(GPIO_ADB, 1);
	ets_delay_us(ADB_1_HIGH - 1);
}

void	adb_tx_reset() {
	/*
	 * ADB spec says reset signal low for 3ms ±30%
	 * Note that the ADB Desktop Bus Mouse G5431 uses 4ms when plugged
	 * ADB mouse init in <70ms, but lets wait 500ms to be sure
	 */

	gpio_set_level(GPIO_ADB, 0);
	ets_delay_us(ADB_RESET);
	gpio_set_level(GPIO_ADB, 1);
	ets_delay_us(500);
}

static inline void	adb_tx_setup() {
	gpio_set_direction(GPIO_ADB, GPIO_MODE_OUTPUT);
	gpio_set_level(GPIO_DIR, 1);
}

static inline void	adb_tx_zero() {
	/* values from AN591 Datasheet minus the estimated call to ets_delay_us */
	gpio_set_level(GPIO_ADB, 0);
	ets_delay_us(ADB_0_LOW - 1);
	gpio_set_level(GPIO_ADB, 1);
	ets_delay_us(ADB_0_HIGH - 1);
}