comedi_fc.c

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/*
    comedi/drivers/comedi_fc.c

    This is a place for code driver writers wish to share between
    two or more drivers.  fc is short
    for frank-common.

    Author:  Frank Mori Hess <[email protected]>
    Copyright (C) 2002 Frank Mori Hess

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program 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 General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

************************************************************************/

#include "../comedidev.h"

#include "comedi_fc.h"

static void increment_scan_progress(struct comedi_subdevice *subd,
                    unsigned int num_bytes)
{
    struct comedi_async *async = subd->async;
    unsigned int scan_length = cfc_bytes_per_scan(subd);

    async->scan_progress += num_bytes;
    if (async->scan_progress >= scan_length) {
        async->scan_progress %= scan_length;
        async->events |= COMEDI_CB_EOS;
    }
}

/* Writes an array of data points to comedi's buffer */
unsigned int cfc_write_array_to_buffer(struct comedi_subdevice *subd,
                       void *data, unsigned int num_bytes)
{
    struct comedi_async *async = subd->async;
    unsigned int retval;

    if (num_bytes == 0)
        return 0;

    retval = comedi_buf_write_alloc(async, num_bytes);
    if (retval != num_bytes) {
        printk(KERN_WARNING "comedi: buffer overrun\n");
        async->events |= COMEDI_CB_OVERFLOW;
        return 0;
    }

    comedi_buf_memcpy_to(async, 0, data, num_bytes);
    comedi_buf_write_free(async, num_bytes);
    increment_scan_progress(subd, num_bytes);
    async->events |= COMEDI_CB_BLOCK;

    return num_bytes;
}
EXPORT_SYMBOL(cfc_write_array_to_buffer);

unsigned int cfc_read_array_from_buffer(struct comedi_subdevice *subd,
                    void *data, unsigned int num_bytes)
{
    struct comedi_async *async = subd->async;

    if (num_bytes == 0)
        return 0;

    num_bytes = comedi_buf_read_alloc(async, num_bytes);
    comedi_buf_memcpy_from(async, 0, data, num_bytes);
    comedi_buf_read_free(async, num_bytes);
    increment_scan_progress(subd, num_bytes);
    async->events |= COMEDI_CB_BLOCK;

    return num_bytes;
}
EXPORT_SYMBOL(cfc_read_array_from_buffer);

unsigned int cfc_handle_events(struct comedi_device *dev,
                   struct comedi_subdevice *subd)
{
    unsigned int events = subd->async->events;

    if (events == 0)
        return events;

    if (events & (COMEDI_CB_EOA | COMEDI_CB_ERROR | COMEDI_CB_OVERFLOW))
        subd->cancel(dev, subd);

    comedi_event(dev, subd);

    return events;
}
EXPORT_SYMBOL(cfc_handle_events);

MODULE_AUTHOR("Frank Mori Hess <[email protected]>");
MODULE_DESCRIPTION("Shared functions for Comedi low-level drivers");
MODULE_LICENSE("GPL");

static int __init comedi_fc_init_module(void)
{
    return 0;
}

static void __exit comedi_fc_cleanup_module(void)
{
}

module_init(comedi_fc_init_module);
module_exit(comedi_fc_cleanup_module);