release/src-rt-6.x.4708/linux/linux-2.6.36/drivers/staging/comedi/drivers/comedi_fc.c

   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
  31 static 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 */
  45 unsigned 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 }
  68 EXPORT_SYMBOL(cfc_write_array_to_buffer);
  69
  70 unsigned 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 }
  86 EXPORT_SYMBOL(cfc_read_array_from_buffer);
  87
  88 unsigned 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 }
 103 EXPORT_SYMBOL(cfc_handle_events);
 104
 105 MODULE_AUTHOR("Frank Mori Hess <fmhess@users.sourceforge.net>");
 106 MODULE_DESCRIPTION("Shared functions for Comedi low-level drivers");
 107 MODULE_LICENSE("GPL");
 108
 109 static int __init comedi_fc_init_module(void)
 110 {
 111         return 0;
 112 }
 113
 114 static void __exit comedi_fc_cleanup_module(void)
 115 {
 116 }
 117
 118 module_init(comedi_fc_init_module);
 119 module_exit(comedi_fc_cleanup_module);