teensy-cores/teensy4/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"

#include "debug/printf.h"

#ifdef RAWHID_INTERFACE // defined by usb_dev.h -> usb_desc.h

#define TX_NUM   4
static transfer_t tx_transfer[TX_NUM] __attribute__ ((used, aligned(32)));
static uint8_t txbuffer[RAWHID_TX_SIZE * TX_NUM];
static uint8_t tx_head=0;

static transfer_t rx_transfer[1] __attribute__ ((used, aligned(32)));
static uint8_t rx_buffer[RAWHID_RX_SIZE];

extern volatile uint8_t usb_configuration;


static void rx_event(transfer_t *t)
{
	//printf("rx\n");
}

void usb_rawhid_configure(void)
{
	printf("usb_rawhid_configure\n");
	memset(tx_transfer, 0, sizeof(tx_transfer));
	memset(rx_transfer, 0, sizeof(rx_transfer));
	tx_head = 0;
	usb_config_tx(RAWHID_TX_ENDPOINT, RAWHID_TX_SIZE, 0, NULL);
	usb_config_rx(RAWHID_RX_ENDPOINT, RAWHID_RX_SIZE, 0, rx_event);
	//usb_config_rx(RAWHID_RX_ENDPOINT, RAWHID_RX_SIZE, 0, NULL); // why does this not work?
	usb_prepare_transfer(rx_transfer + 0, rx_buffer, RAWHID_RX_SIZE, 0);
	usb_receive(RAWHID_RX_ENDPOINT, rx_transfer + 0);
}

int usb_rawhid_recv(void *buffer, uint32_t timeout)
{
	uint32_t wait_begin_at = systick_millis_count;
	while (1) {
		if (!usb_configuration) return -1; // usb not enumerated by host
		uint32_t status = usb_transfer_status(rx_transfer);
		if (!(status & 0x80)) break; // transfer descriptor ready
		if (systick_millis_count - wait_begin_at > timeout) return 0;
		yield();
	}
	memcpy(buffer, rx_buffer, RAWHID_RX_SIZE);
	memset(rx_transfer, 0, sizeof(rx_transfer));
	usb_prepare_transfer(rx_transfer + 0, rx_buffer, RAWHID_RX_SIZE, 0);
	usb_receive(RAWHID_RX_ENDPOINT, rx_transfer + 0);
	return RAWHID_RX_SIZE;
}

int usb_rawhid_send(const void *buffer, uint32_t timeout)
{
	transfer_t *xfer = tx_transfer + tx_head;
	uint32_t wait_begin_at = systick_millis_count;

	while (1) {
		if (!usb_configuration) return -1; // usb not enumerated by host
		uint32_t status = usb_transfer_status(xfer);
		if (!(status & 0x80)) break; // transfer descriptor ready
		if (systick_millis_count - wait_begin_at > timeout) return 0;
		yield();
	}
	uint8_t *txdata = txbuffer + (tx_head * RAWHID_TX_SIZE);
	memcpy(txdata, buffer, RAWHID_TX_SIZE);
	usb_prepare_transfer(xfer, txdata, RAWHID_TX_SIZE, 0);
	usb_transmit(RAWHID_TX_ENDPOINT, xfer);
	if (++tx_head >= TX_NUM) tx_head = 0;
	return RAWHID_TX_SIZE;
}

int usb_rawhid_available(void)
{
	if (!usb_configuration) return 0;
	if (!(usb_transfer_status(rx_transfer) & 0x80)) return RAWHID_RX_SIZE;
	return 0;
}

#endif // RAWHID_INTERFACE