LXR linux/drivers/staging/comedi/drivers/comedi

   1/*
   2    comedi/drivers/comedi_fc.c
   3
   4    This is a place for code driver writers wish to share between
   5    two or more drivers.  fc is short
   6    for frank-common.
   7
   8    Author:  Frank Mori Hess <fmhess@users.sourceforge.net>
   9    Copyright (C) 2002 Frank Mori Hess
  10
  11    This program is free software; you can redistribute it and/or modify
  12    it under the terms of the GNU General Public License as published by
  13    the Free Software Foundation; either version 2 of the License, or
  14    (at your option) any later version.
  15
  16    This program is distributed in the hope that it will be useful,
  17    but WITHOUT ANY WARRANTY; without even the implied warranty of
  18    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19    GNU General Public License for more details.
  20
  21    You should have received a copy of the GNU General Public License
  22    along with this program; if not, write to the Free Software
  23    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  24
  25************************************************************************/
  26
  27#include "../comedidev.h"
  28
  29#include "comedi_fc.h"
  30
  31static void increment_scan_progress(struct comedi_subdevice *subd,
  32                                    unsigned int num_bytes)
  33{
  34        struct comedi_async *async = subd->async;
  35        unsigned int scan_length = cfc_bytes_per_scan(subd);
  36
  37        async->scan_progress += num_bytes;
  38        if (async->scan_progress >= scan_length) {
  39                async->scan_progress %= scan_length;
  40                async->events |= COMEDI_CB_EOS;
  41        }
  42}
  43
  44/* Writes an array of data points to comedi's buffer */
  45unsigned int cfc_write_array_to_buffer(struct comedi_subdevice *subd,
  46                                       void *data, unsigned int num_bytes)
  47{
  48        struct comedi_async *async = subd->async;
  49        unsigned int retval;
  50
  51        if (num_bytes == 0)
  52                return 0;
  53
  54        retval = comedi_buf_write_alloc(async, num_bytes);
  55        if (retval != num_bytes) {
  56                printk(KERN_WARNING "comedi: buffer overrun\n");
  57                async->events |= COMEDI_CB_OVERFLOW;
  58                return 0;
  59        }
  60
  61        comedi_buf_memcpy_to(async, 0, data, num_bytes);
  62        comedi_buf_write_free(async, num_bytes);
  63        increment_scan_progress(subd, num_bytes);
  64        async->events |= COMEDI_CB_BLOCK;
  65
  66        return num_bytes;
  67}
  68EXPORT_SYMBOL(cfc_write_array_to_buffer);
  69
  70unsigned int cfc_read_array_from_buffer(struct comedi_subdevice *subd,
  71                                        void *data, unsigned int num_bytes)
  72{
  73        struct comedi_async *async = subd->async;
  74
  75        if (num_bytes == 0)
  76                return 0;
  77
  78        num_bytes = comedi_buf_read_alloc(async, num_bytes);
  79        comedi_buf_memcpy_from(async, 0, data, num_bytes);
  80        comedi_buf_read_free(async, num_bytes);
  81        increment_scan_progress(subd, num_bytes);
  82        async->events |= COMEDI_CB_BLOCK;
  83
  84        return num_bytes;
  85}
  86EXPORT_SYMBOL(cfc_read_array_from_buffer);
  87
  88unsigned int cfc_handle_events(struct comedi_device *dev,
  89                               struct comedi_subdevice *subd)
  90{
  91        unsigned int events = subd->async->events;
  92
  93        if (events == 0)
  94                return events;
  95
  96        if (events & (COMEDI_CB_EOA | COMEDI_CB_ERROR | COMEDI_CB_OVERFLOW))
  97                subd->cancel(dev, subd);
  98
  99        comedi_event(dev, subd);
 100
 101        return events;
 102}
 103EXPORT_SYMBOL(cfc_handle_events);
 104
 105MODULE_AUTHOR("Frank Mori Hess <fmhess@users.sourceforge.net>");
 106MODULE_DESCRIPTION("Shared functions for Comedi low-level drivers");
 107MODULE_LICENSE("GPL");
 108
 109static int __init comedi_fc_init_module(void)
 110{
 111        return 0;
 112}
 113
 114static void __exit comedi_fc_cleanup_module(void)
 115{
 116}
 117
 118module_init(comedi_fc_init_module);
 119module_exit(comedi_fc_cleanup_module);
 120