libcasio/src/stream/builtin/libusb.c

/* ****************************************************************************
 * stream/builtin/libusb.c -- built-in libusb stream.
 * Copyright (C) 2016-2017 Thomas "Cakeisalie5" Touhey <thomas@touhey.fr>
 *
 * This file is part of libcasio.
 * libcasio is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 3.0 of the License,
 * or (at your option) any later version.
 *
 * libcasio 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with libcasio; if not, see <http://www.gnu.org/licenses/>.
 * ************************************************************************* */
#include "../../internals.h"
#ifndef LIBCASIO_DISABLED_LIBUSB
# include <libusb.h>

/* libusb cookie structure */
# define BUFSIZE 2048
typedef struct {
	libusb_context *_context;
	libusb_device_handle *_handle;

	/* timeouts */
	unsigned int tmread, tmwrite;

	/* buffer control */
	ssize_t _start, _end;
	unsigned char _buffer[BUFSIZE];
} libusb_cookie_t;
/* ************************************************************************* */
/*  Settings, close callbacks                                                */
/* ************************************************************************* */
/**
 *	casio_libusb_settm:
 *	Set timeouts.
 *
 *	@arg	vcookie		the cookie (uncasted).
 *	@arg	timeouts	the timeouts.
 *	@return				the error code (0 if ok).
 */

CASIO_LOCAL int casio_libusb_settm(void *vcookie, const casio_timeouts_t *timeouts)
{
	libusb_cookie_t *cookie = (void*)vcookie;

	/* set the timeouts */
	cookie->tmread =  timeouts->casio_timeouts_read;
	cookie->tmwrite = timeouts->casio_timeouts_write;

	/* no error! */
	return (0);
}

/**
 *	casio_libusb_close:
 *	Close libusb cookie.
 *
 *	@arg	vcookie		the cookie (uncasted).
 *	@return				the error code (0 if ok).
 */

CASIO_LOCAL int casio_libusb_close(void *vcookie)
{
	libusb_cookie_t *cookie = (libusb_cookie_t*)vcookie;

	if (cookie->_handle) libusb_close(cookie->_handle);
	if (cookie->_context) libusb_exit(cookie->_context);
	casio_free(vcookie);
	return (0);
}
/* ************************************************************************* */
/*  Character stream callbacks                                               */
/* ************************************************************************* */
/**
 *	casio_libusb_read:
 *	Read using libusb cookie.
 *
 *	@arg	vcookie		the cookie (voided)
 *	@arg	data		the data pointer.
 *	@arg	size		the data size.
 *	@return				the error code (0 if ok).
 */

# define ENDPOINT_IN (LIBUSB_ENDPOINT_IN | LIBUSB_TRANSFER_TYPE_BULK)
CASIO_LOCAL int casio_libusb_read(void *vcookie, unsigned char *dest, size_t size)
{
	int libusberr; libusb_cookie_t *cookie = (libusb_cookie_t*)vcookie;
	size_t tocopy;

	/* transmit what's already in the buffer */
	if (cookie->_start <= cookie->_end) {
		tocopy = cookie->_end - cookie->_start + 1;
		if (tocopy > size) tocopy = size;

		memcpy(dest, &cookie->_buffer[cookie->_start], tocopy);
		cookie->_start += tocopy;
		dest += tocopy;
		size -= tocopy;
	}

	/* main receiving loop */
	while (size) {
		int recv;

		/* make the transfer. */
		libusberr = libusb_bulk_transfer(cookie->_handle, ENDPOINT_IN,
			cookie->_buffer, BUFSIZE, &recv, cookie->tmread);
		switch (libusberr) {
			case 0: break;

			case LIBUSB_ERROR_PIPE:
			case LIBUSB_ERROR_NO_DEVICE:
			case LIBUSB_ERROR_IO:
				return (casio_error_nocalc);

			case LIBUSB_ERROR_TIMEOUT:
				return (casio_error_timeout);

			default:
				msg((ll_fatal, "libusb error was %d: %s", libusberr,
					libusb_strerror(libusberr)));
				return (casio_error_unknown);
		}

		/* get the current size to copy */
		tocopy = (size_t)recv;
		if (tocopy > size) tocopy = size;

		/* copy to destination */
		memcpy(dest, cookie->_buffer, tocopy);
		dest += tocopy;
		size -= tocopy;

		/* correct start and end points */
		cookie->_start = tocopy;
		cookie->_end = (size_t)recv - 1;
	}

	/* no error */
	return (0);
}

/**
 *	casio_libusb_write:
 *	Write using libusb cookie.
 *
 *	@arg	vcookie		the cookie (uncasted)
 *	@arg	data		the source.
 *	@arg	size		the source size.
 *	@return				the error code (0 if ok).
 */

# define ENDPOINT_OUT (LIBUSB_ENDPOINT_OUT | LIBUSB_TRANSFER_TYPE_ISOCHRONOUS)
CASIO_LOCAL int casio_libusb_write(void *vcookie,
	const unsigned char *data, size_t size)
{
	libusb_cookie_t *cookie = (libusb_cookie_t*)vcookie;
	int sent, libusberr;

	/* Make the transfer. */
	libusberr = libusb_bulk_transfer(cookie->_handle, ENDPOINT_OUT,
		(unsigned char*)data, size, &sent, cookie->tmwrite);
	switch (libusberr) {
		case 0: break;

		case LIBUSB_ERROR_PIPE:
		case LIBUSB_ERROR_NO_DEVICE:
			return (casio_error_nocalc);

		default:
			msg((ll_fatal, "libusb error was %d: %s", libusberr,
				libusb_strerror(libusberr)));
			return (casio_error_unknown);
	}

	/* no error! */
	return (0);
}
/* ************************************************************************* */
/*  Main libusb function                                                     */
/* ************************************************************************* */
# include <stdlib.h>
# include <string.h>

/* libusb callbacks. */
CASIO_LOCAL const casio_streamfuncs_t casio_libusb_callbacks = {
	casio_libusb_close,
	NULL, casio_libusb_settm,
	casio_libusb_read,
	casio_libusb_write,
	NULL, NULL
};

/**
 *	casio_openusb_libusb:
 *	Initialize a stream with USB device using libusb.
 *
 *	@arg	handle		the handle to create.
 *	@arg	flags		the flags.
 *	@return				the error code (0 if you're a knoop).
 */

int CASIO_EXPORT casio_openusb_libusb(casio_stream_t **stream)
{
	int err = 0, uerr, id, device_count;
	libusb_context *context = NULL;
	libusb_device *calc = NULL, **device_list = NULL;
	libusb_device_handle *dhandle = NULL;
	casio_streamtype_t type = casio_streamtype_usb;
	libusb_cookie_t *cookie = NULL;

	/* open up context */
	if (libusb_init(&context)) {
		msg((ll_fatal, "Couldn't create libusb context."));
		return (casio_error_nocalc);
	}

	/* get device list */
	device_count = libusb_get_device_list(context, &device_list);
	if (device_count < 0) {
		msg((ll_fatal, "couldn't get device list."));
		err = casio_error_nocalc;
		goto fail;
	}

	/* look for the calculator */
	for (id = 0; id < device_count; id++) {
		struct libusb_device_descriptor descriptor;

		/* get the device descriptor */
		if (libusb_get_device_descriptor(device_list[id], &descriptor))
			continue;

		/* check if is a CASIO Protocol 7.00 device */
		if (descriptor.idVendor  == 0x07cf
		 && descriptor.idProduct == 0x6101) {
			calc = device_list[id];
			break;
		}

		/* check if is a CASIO SCSI device */
		if (descriptor.idVendor  == 0x07cf
		 && descriptor.idProduct == 0x6102) {
			calc = device_list[id];
			type |= casio_streamtype_scsi;
			break;
		}
	}

	/* the calculator wasn't found */
	if (!calc) {
		libusb_free_device_list(device_list, 1);
		err = casio_error_nocalc;
		goto fail;
	}

	/* get calculator handle */
	msg((ll_info, "getting the device handle"));
	uerr = libusb_open(calc, &dhandle);
	libusb_free_device_list(device_list, 1);

	/* check if we have the handle */
	switch (uerr) {
	/* couldn't get access to the device */
	case LIBUSB_ERROR_ACCESS:
		err = casio_error_noaccess;
		goto fail;

	/* default cases */
	case 0: break;
	default:
		msg((ll_fatal, "libusb_open returned %d: %s",
			uerr, libusb_error_name(uerr)));
		err = casio_error_noaccess;
		goto fail;
	}

	/* disconnect any kernel driver */
	msg((ll_info, "Detaching kernel driver, if any."));
	uerr = libusb_detach_kernel_driver(dhandle, 0);
	switch(uerr) {
		/* cases where it's okay */
		case 0: case LIBUSB_ERROR_NOT_SUPPORTED:
		case LIBUSB_ERROR_NOT_FOUND: break;

		/* cases where it's not okay */
		case LIBUSB_ERROR_INVALID_PARAM:
			msg((ll_fatal, "Interface 0 doesn't exist...?"));
			err = casio_error_nocalc;
			goto fail;
		case LIBUSB_ERROR_NO_DEVICE:
			err = casio_error_nocalc;
			goto fail;
		default:
			msg((ll_fatal, "libusb returned %d: %s",
				uerr, libusb_error_name(uerr)));
			goto fail;
	}

	/* check if the interface is active */
	libusb_kernel_driver_active(dhandle, 0);

	/* claim the interface */
	msg((ll_info, "Claiming the interface."));
	uerr = libusb_claim_interface(dhandle, 0);
	switch(uerr) {
		/* cases where it's okay (not a lot) */
		case 0: break;

		/* cases where it's not okay */
		case LIBUSB_ERROR_NO_DEVICE:
		case LIBUSB_ERROR_NOT_FOUND:
			err = casio_error_nocalc;
			goto fail;
		case LIBUSB_ERROR_BUSY:
			msg((ll_info,
				"Another program/driver has claimed the interface..."));
			err = casio_error_noaccess;
			goto fail;
		default:
			msg((ll_info, "libusb returned %d: %s",
				uerr, libusb_error_name(uerr)));
			goto fail;
	}

	/* make the cookie */
	cookie = casio_alloc(1, sizeof(libusb_cookie_t));
	err = casio_error_alloc;
	if (!cookie) goto fail;
	cookie->_context = context;
	cookie->_handle = dhandle;
	cookie->_start = 0;
	cookie->_end = -1;

	/* final call. */
	return (casio_open(stream, CASIO_OPENMODE_READ | CASIO_OPENMODE_WRITE,
		casio_streamtype_usb, cookie, &casio_libusb_callbacks));
fail:
	if (cookie)  casio_free(cookie);
	if (dhandle) libusb_close(dhandle);
	if (context) libusb_exit(context);
	return (err);
}

#endif