source: mainline/uspace/lib/usb/src/devpoll.c@ 4bf94df

/*
 * Copyright (c) 2011 Vojtech Horky
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup libusb
 * @{
 */
/** @file
 * USB device driver framework - automatic interrupt polling.
 */
#include <usb/devdrv.h>
#include <usb/request.h>
#include <usb/debug.h>
#include <errno.h>
#include <str_error.h>
#include <assert.h>

/** Maximum number of failed consecutive requests before announcing failure. */
#define MAX_FAILED_ATTEMPTS 3

/** Data needed for polling. */
typedef struct {
        usb_device_t *dev;
        size_t pipe_index;
        usb_polling_callback_t callback;
        usb_polling_terminted_callback_t terminated_callback;
        size_t request_size;
        uint8_t *buffer;
        void *custom_arg;
} polling_data_t;

/** Polling fibril.
 *
 * @param arg Pointer to polling_data_t.
 * @return Always EOK.
 */
static int polling_fibril(void *arg)
{
        polling_data_t *polling_data = (polling_data_t *) arg;
        assert(polling_data);

        usb_endpoint_pipe_t *pipe
            = polling_data->dev->pipes[polling_data->pipe_index].pipe;

        size_t failed_attempts = 0;
        while (failed_attempts < MAX_FAILED_ATTEMPTS) {
                int rc;

                rc = usb_endpoint_pipe_start_session(pipe);
                if (rc != EOK) {
                        failed_attempts++;
                        continue;
                }

                size_t actual_size;
                rc = usb_endpoint_pipe_read(pipe, polling_data->buffer,
                    polling_data->request_size, &actual_size);

                /* Quit the session regardless of errors. */
                usb_endpoint_pipe_end_session(pipe);

                if (rc != EOK) {
                        failed_attempts++;
                        continue;
                }

                /* We have the data, execute the callback now. */
                bool carry_on = polling_data->callback(polling_data->dev,
                    polling_data->buffer, actual_size,
                    polling_data->custom_arg);

                if (!carry_on) {
                        failed_attempts = 0;
                        break;
                }

                /* Reset as something might be only a temporary problem. */
                failed_attempts = 0;
        }

        if (failed_attempts > 0) {
                usb_log_error(
                    "Polling of device `%s' terminated: recurring failures.\n",
                    polling_data->dev->ddf_dev->name);
        }

        if (polling_data->terminated_callback != NULL) {
                polling_data->terminated_callback(polling_data->dev,
                    failed_attempts > 0, polling_data->custom_arg);
        }

        /* Free the allocated memory. */
        free(polling_data->buffer);
        free(polling_data);

        return EOK;
}

/** Start automatic device polling over interrupt in pipe.
 *
 * @warning It is up to the callback to produce delays between individual
 * requests.
 *
 * @warning There is no guarantee when the request to the device
 * will be sent for the first time (it is possible that this
 * first request would be executed prior to return from this function).
 *
 * @param dev Device to be periodically polled.
 * @param pipe_index Index of the endpoint pipe used for polling.
 * @param callback Callback when data are available.
 * @param request_size How many bytes to ask for in each request.
 * @param terminated_callback Callback when polling is terminated.
 * @param arg Custom argument (passed as is to the callbacks).
 * @return Error code.
 * @retval EOK New fibril polling the device was already started.
 */
int usb_device_auto_poll(usb_device_t *dev, size_t pipe_index,
    usb_polling_callback_t callback, size_t request_size,
    usb_polling_terminted_callback_t terminated_callback, void *arg)
{
        if ((dev == NULL) || (callback == NULL)) {
                return EBADMEM;
        }
        if (request_size == 0) {
                return EINVAL;
        }
        if ((dev->pipes[pipe_index].pipe->transfer_type != USB_TRANSFER_INTERRUPT)
            || (dev->pipes[pipe_index].pipe->direction != USB_DIRECTION_IN)) {
                return EINVAL;
        }

        polling_data_t *polling_data = malloc(sizeof(polling_data_t));
        if (polling_data == NULL) {
                return ENOMEM;
        }

        /* Allocate now to prevent immediate failure in the polling fibril. */
        polling_data->buffer = malloc(request_size);
        if (polling_data->buffer == NULL) {
                free(polling_data);
                return ENOMEM;
        }
        polling_data->dev = dev;
        polling_data->pipe_index = pipe_index;
        polling_data->callback = callback;
        polling_data->terminated_callback = terminated_callback;
        polling_data->request_size = request_size;
        polling_data->custom_arg = arg;

        fid_t fibril = fibril_create(polling_fibril, polling_data);
        if (fibril == 0) {
                free(polling_data->buffer);
                free(polling_data);
                /* FIXME: better error code. */
                return ENOMEM;
        }
        fibril_add_ready(fibril);

        /* The allocated buffer etc. will be freed by the fibril. */

        return EOK;
}

/**
 * @}
 */