teensy-cores/teensy3/usb_rawhid.c

/* Teensyduino Core Library
 * http://www.pjrc.com/teensy/
 * Copyright (c) 2017 PJRC.COM, LLC.
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * 1. The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * 2. If the Software is incorporated into a build system that allows
 * selection among a list of target devices, then similar target
 * devices manufactured by PJRC.COM must be included in the list of
 * target devices and selectable in the same manner.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include "usb_dev.h"
#include "usb_rawhid.h"
#include "core_pins.h" // for yield(), millis()
#include <string.h>    // for memcpy()
//#include "HardwareSerial.h"

#ifdef RAWHID_INTERFACE // defined by usb_dev.h -> usb_desc.h
#if F_CPU >= 20000000

int usb_rawhid_recv(void *buffer, uint32_t timeout)
{
	usb_packet_t *rx_packet;
	uint32_t begin = millis();

	while (1) {
		if (!usb_configuration) return -1;
		rx_packet = usb_rx(RAWHID_RX_ENDPOINT);
		if (rx_packet) break;
		if (millis() - begin > timeout || !timeout) return 0;
		yield();
	}
	memcpy(buffer, rx_packet->buf, RAWHID_RX_SIZE);
	usb_free(rx_packet);
	return RAWHID_RX_SIZE;
}

int usb_rawhid_available(void)
{
	uint32_t count;

	if (!usb_configuration) return 0;
	count = usb_rx_byte_count(RAWHID_RX_ENDPOINT);
	return count;
}

// Maximum number of transmit packets to queue so we don't starve other endpoints for memory
#define TX_PACKET_LIMIT 4

int usb_rawhid_send(const void *buffer, uint32_t timeout)
{
	usb_packet_t *tx_packet;
	uint32_t begin = millis();

	while (1) {
		if (!usb_configuration) return -1;
		if (usb_tx_packet_count(RAWHID_TX_ENDPOINT) < TX_PACKET_LIMIT) {
			tx_packet = usb_malloc();
			if (tx_packet) break;
		}
		if (millis() - begin > timeout) return 0;
		yield();
	}
	memcpy(tx_packet->buf, buffer, RAWHID_TX_SIZE);
	tx_packet->len = RAWHID_TX_SIZE;
	usb_tx(RAWHID_TX_ENDPOINT, tx_packet);
	return RAWHID_TX_SIZE;
}

#endif // F_CPU
#endif // RAWHID_INTERFACE