usb.c

/*
 * libiio - Library for interfacing industrial I/O (IIO) devices
 *
 * Copyright (C) 2015 Analog Devices, Inc.
 * Author: Paul Cercueil <paul.cercueil@analog.com>
 *
 * This library 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 2.1 of the License, or (at your option) any later version.
 *
 * This library 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.
 *
 * */

#include "debug.h"
#include "iio-lock.h"
#include "iio-private.h"
#include "iiod-client.h"

#include <errno.h>
#include <libusb-1.0/libusb.h>
#include <stdbool.h>
#include <string.h>

#define DEFAULT_TIMEOUT_MS 5000

/* Endpoint for non-streaming operations */
#define EP_OPS		1

struct iio_context_pdata {
	libusb_context *ctx;
	libusb_device_handle *hdl;

	struct iiod_client *iiod_client;

	/* Lock for non-streaming operations */
	struct iio_mutex *lock;
};

static const unsigned int libusb_to_errno_codes[] = {
	[- LIBUSB_ERROR_INVALID_PARAM]	= EINVAL,
	[- LIBUSB_ERROR_ACCESS]		= EACCES,
	[- LIBUSB_ERROR_NO_DEVICE]	= ENODEV,
	[- LIBUSB_ERROR_NOT_FOUND]	= ENXIO,
	[- LIBUSB_ERROR_BUSY]		= EBUSY,
	[- LIBUSB_ERROR_TIMEOUT]	= ETIMEDOUT,
	[- LIBUSB_ERROR_OVERFLOW]	= EIO,
	[- LIBUSB_ERROR_PIPE]		= EPIPE,
	[- LIBUSB_ERROR_INTERRUPTED]	= EINTR,
	[- LIBUSB_ERROR_NO_MEM]		= ENOMEM,
	[- LIBUSB_ERROR_NOT_SUPPORTED]	= ENOSYS,
};

static unsigned int libusb_to_errno(int error)
{
	switch ((enum libusb_error) error) {
	case LIBUSB_ERROR_INVALID_PARAM:
	case LIBUSB_ERROR_ACCESS:
	case LIBUSB_ERROR_NO_DEVICE:
	case LIBUSB_ERROR_NOT_FOUND:
	case LIBUSB_ERROR_BUSY:
	case LIBUSB_ERROR_TIMEOUT:
	case LIBUSB_ERROR_PIPE:
	case LIBUSB_ERROR_INTERRUPTED:
	case LIBUSB_ERROR_NO_MEM:
	case LIBUSB_ERROR_NOT_SUPPORTED:
		return libusb_to_errno_codes[- (int) error];
	case LIBUSB_ERROR_IO:
	case LIBUSB_ERROR_OTHER:
	case LIBUSB_ERROR_OVERFLOW:
	default:
		return EIO;
	}
}

static int usb_get_version(const struct iio_context *ctx,
		unsigned int *major, unsigned int *minor, char git_tag[8])
{
	return iiod_client_get_version(ctx->pdata->iiod_client,
			EP_OPS, major, minor, git_tag);
}

static void usb_shutdown(struct iio_context *ctx)
{
	iio_mutex_destroy(ctx->pdata->lock);

	iiod_client_destroy(ctx->pdata->iiod_client);

	libusb_close(ctx->pdata->hdl);
	libusb_exit(ctx->pdata->ctx);
}

static const struct iio_backend_ops usb_ops = {
	.get_version = usb_get_version,
	.shutdown = usb_shutdown,
};

static ssize_t write_data_sync(struct iio_context_pdata *pdata,
		int ep, const char *data, size_t len)
{
	int transferred, ret;

	ret = libusb_bulk_transfer(pdata->hdl, ep | LIBUSB_ENDPOINT_OUT,
			(char *) data, len, &transferred, DEFAULT_TIMEOUT_MS);
	if (ret)
		return -libusb_to_errno(ret);
	else
		return transferred != len ? -EIO : len;
}

static ssize_t read_data_sync(struct iio_context_pdata *pdata,
		int ep, char *buf, size_t len)
{
	int transferred, ret;

	ret = libusb_bulk_transfer(pdata->hdl, ep | LIBUSB_ENDPOINT_IN,
			buf, len, &transferred, DEFAULT_TIMEOUT_MS);
	if (ret)
		return -libusb_to_errno(ret);
	else
		return transferred;
}

static struct iiod_client_ops usb_iiod_client_ops = {
	.write = write_data_sync,
	.read = read_data_sync,
	.read_line = read_data_sync,
};

struct iio_context * usb_create_context(unsigned short vid, unsigned short pid)
{
	libusb_context *usb_ctx;
	libusb_device_handle *hdl;
	struct iio_context *ctx;
	struct iio_context_pdata *pdata;
	unsigned int i;
	int ret;

	pdata = calloc(1, sizeof(*pdata));
	if (!pdata) {
		ERROR("Unable to allocate pdata\n");
		ret = -ENOMEM;
		goto err_set_errno;
	}

	pdata->lock = iio_mutex_create();
	if (!pdata->lock) {
		ERROR("Unable to create mutex\n");
		ret = -ENOMEM;
		goto err_free_pdata;
	}

	pdata->iiod_client = iiod_client_new(pdata, pdata->lock,
			&usb_iiod_client_ops);
	if (!pdata->iiod_client) {
		ERROR("Unable to create IIOD client\n");
		ret = -errno;
		goto err_destroy_mutex;
	}

	ret = libusb_init(&usb_ctx);
	if (ret) {
		ret = -libusb_to_errno(ret);
		ERROR("Unable to init libusb: %i\n", ret);
		goto err_free_pdata;
	}

	hdl = libusb_open_device_with_vid_pid(usb_ctx, vid, pid);
	if (!hdl) {
		ERROR("Unable to find device 0x%04hx:0x%04hx\n", vid, pid);
		ret = -ENODEV;
		goto err_libusb_exit;
	}

	libusb_set_auto_detach_kernel_driver(hdl, true);

	ret = libusb_claim_interface(hdl, 0);
	if (ret) {
		ret = -libusb_to_errno(ret);
		ERROR("Unable to claim interface 0: %i\n", ret);
		goto err_libusb_close;
	}

	pdata->ctx = usb_ctx;
	pdata->hdl = hdl;

	ctx = iiod_client_create_context(pdata->iiod_client, EP_OPS);
	if (!ctx)
		goto err_libusb_close;

	ctx->name = "usb";
	ctx->ops = &usb_ops;
	ctx->pdata = pdata;

	DEBUG("Initializing context...\n");
	ret = iio_context_init(ctx);
	if (ret < 0)
		goto err_context_destroy;

	return ctx;

err_context_destroy:
	iio_context_destroy(ctx);
	errno = -ret;
	return NULL;

err_libusb_close:
	libusb_close(hdl);
err_libusb_exit:
	libusb_exit(usb_ctx);
err_destroy_iiod_client:
	iiod_client_destroy(pdata->iiod_client);
err_destroy_mutex:
	iio_mutex_destroy(pdata->lock);
err_free_pdata:
	free(pdata);
err_set_errno:
	errno = -ret;
	return NULL;
}