comedi_test.c

rtlinux-3.2-pre3.tar.bz2 rtlinux3.2-pre3的源代码

/*
    comedi_test.c driver

    Generates fake waveform signals that can be read through
    the command interface.  It does _not_ read from any board;
    it just generates deterministic waveforms.
    Useful for various testing purposes.

    Copyright (C) 2002 Joachim Wuttke <[e-mail]>
    Copyright (C) 2002 Frank Mori Hess <[e-mail]>

    COMEDI - Linux Control and Measurement Device Interface
    Copyright (C) 2000 David A. Schleef <[e-mail]>

    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.

************************************************************************/
/*
Driver: comedi_test.o
Description: generates fake waveforms
Author: Joachim Wuttke <[e-mail]>, Frank Mori Hess
  <[e-mail]>, ds
Devices:
Status: works
Updated: Sat, 16 Mar 2002 17:34:48 -0800

This driver is mainly for testing purposes, but can also be used to
generate sample waveforms on systems that don't have data acquisition
hardware.

Configuration options:
  [0] - Amplitude in microvolts for fake waveforms (default 1 volt)
  [1] - Period in microseconds for fake waveforms (default 0.1 sec)

Generates a sawtooth wave on channel 0, square wave on channel 1, additional
waveforms could be added to other channels (currently they return flatline
zero volts).

*/

#include <linux/comedidev.h>

#include <asm/div64.h>

#include "comedi_fc.h"


/* Board descriptions */
typedef struct waveform_board_struct{
	char *name;
	int ai_chans;
	int ai_bits;
	int have_dio;
} waveform_board;

#define N_CHANS 8

static waveform_board waveform_boards[] = {
	{
	name:           "comedi_test",
	ai_chans:       N_CHANS,
	ai_bits:        16,
	have_dio:       0,
	},
};
#define thisboard ((waveform_board *)dev->board_ptr)

/* Data unique to this driver */
typedef struct{
	struct timer_list timer;
	struct timeval last; // time at which last timer interrupt occured
	unsigned int uvolt_amplitude;	// waveform amplitude in microvolts
	unsigned long usec_period;	// waveform period in microseconds
	volatile unsigned long usec_current;	// current time (modulo waveform period)
	volatile unsigned long usec_remainder;	// usec since last scan;
	volatile unsigned long ai_count;	// number of conversions remaining
	unsigned int scan_period;	// scan period in usec
	unsigned int convert_period;	// conversion period in usec
	volatile unsigned timer_running : 1;
	volatile lsampl_t ao_loopbacks[N_CHANS];
} waveform_private;
#define devpriv ((waveform_private *)dev->private)

static int waveform_attach(comedi_device *dev,comedi_devconfig *it);
static int waveform_detach(comedi_device *dev);
static comedi_driver driver_waveform={
	driver_name:    "comedi_test",
	module:         THIS_MODULE,
	attach:         waveform_attach,
	detach:         waveform_detach,
	board_name:     waveform_boards,
	offset:         sizeof(waveform_board),
	num_names:      sizeof(waveform_boards) / sizeof(waveform_board),
};
COMEDI_INITCLEANUP(driver_waveform);

static int waveform_ai_cmdtest(comedi_device *dev,comedi_subdevice *s,
	comedi_cmd *cmd);
static int waveform_ai_cmd(comedi_device *dev, comedi_subdevice *s);
static int waveform_ai_cancel(comedi_device *dev, comedi_subdevice *s);
static int waveform_ai_insn_read(comedi_device *dev, comedi_subdevice *s, comedi_insn *insn, lsampl_t *data);
static int waveform_ao_insn_write(comedi_device *dev, comedi_subdevice *s, comedi_insn *insn, lsampl_t *data);
static sampl_t fake_sawtooth(comedi_device *dev, unsigned int range, unsigned long current_time);
static sampl_t fake_squarewave(comedi_device *dev, unsigned int range, unsigned long current_time);
static sampl_t fake_flatline(comedi_device *dev, unsigned int range, unsigned long current_time);
static sampl_t fake_waveform(comedi_device *dev, unsigned int channel,
	unsigned int range, unsigned long current_time);

static const int nano_per_micro = 1000;	// 1000 nanosec in a microsec

// fake analog input ranges
static comedi_lrange waveform_ai_ranges =
{
	2,
	{
		BIP_RANGE(10),
		BIP_RANGE(5),
	}
};

/*
   This is the background routine used to generate arbitrary data.
   It should run in the background; therefore it is scheduled by
   a timer mechanism.
*/
static void waveform_ai_interrupt(unsigned long arg)
{
	comedi_device *dev = (comedi_device*) arg;
	comedi_async *async = dev->read_subdev->async;
	comedi_cmd *cmd = &async->cmd;
	unsigned int i, j;
	// all times in microsec
	unsigned long elapsed_time;
	unsigned int num_scans;
	struct timeval now;

	do_gettimeofday(&now);

	elapsed_time = 1000000 * (now.tv_sec - devpriv->last.tv_sec) + now.tv_usec - devpriv->last.tv_usec;
	devpriv->last = now;
	num_scans = (devpriv->usec_remainder + elapsed_time) / devpriv->scan_period;
	devpriv->usec_remainder = (devpriv->usec_remainder + elapsed_time) % devpriv->scan_period;
	async->events = 0;

	for(i = 0; i < num_scans; i++)
	{
		for( j = 0; j < cmd->chanlist_len; j++)
		{
			cfc_write_to_buffer( dev->read_subdev,
				fake_waveform(dev, CR_CHAN(cmd->chanlist[j]), CR_RANGE(cmd->chanlist[j]),
					devpriv->usec_current + i * devpriv->scan_period + j * devpriv->convert_period));
		}
		devpriv->ai_count++;
		if(cmd->stop_src == TRIG_COUNT && devpriv->ai_count >= cmd->stop_arg)
		{
			async->events |= COMEDI_CB_EOA;
			break;
		}
	}

	devpriv->usec_current += elapsed_time;
	devpriv->usec_current %= devpriv->usec_period;

	if((async->events & COMEDI_CB_EOA) == 0 && devpriv->timer_running)
		mod_timer(&devpriv->timer, jiffies + 1);
	else
		del_timer(&devpriv->timer);

	comedi_event(dev, dev->read_subdev, async->events);
}

static int waveform_attach(comedi_device *dev,comedi_devconfig *it)
{
	comedi_subdevice *s;
	int amplitude = it->options[0];
	int period = it->options[1];

	printk("comedi%d: comedi_test: ", dev->minor);

	dev->board_name = thisboard->name;

	if(alloc_private(dev, sizeof(waveform_private)) < 0)
		return -ENOMEM;

	// set default amplitude and period
	if(amplitude <=0)
		amplitude = 1000000;	// 1 volt
	if(period <= 0)
		period = 100000;	// 0.1 sec

	devpriv->uvolt_amplitude = amplitude;
	devpriv->usec_period = period;

	printk("%i microvolt, %li microsecond waveform ", devpriv->uvolt_amplitude, devpriv->usec_period);
	dev->n_subdevices = 2;
	if(alloc_subdevices(dev, dev->n_subdevices) < 0) return -ENOMEM;

	s = dev->subdevices + 0;
	dev->read_subdev = s;
	/* analog input subdevice */
	s->type = COMEDI_SUBD_AI;
	s->subdev_flags = SDF_READABLE | SDF_GROUND;
	s->n_chan = thisboard->ai_chans;
	s->maxdata = (1 << thisboard->ai_bits) - 1;
	s->range_table = &waveform_ai_ranges;
	s->len_chanlist = s->n_chan * 2;
	s->insn_read = waveform_ai_insn_read; // apparently, we do not need waveform_ai_rinsn;
	s->do_cmd = waveform_ai_cmd;
	s->do_cmdtest = waveform_ai_cmdtest;
	s->cancel = waveform_ai_cancel;

	s = dev->subdevices + 1;
	dev->read_subdev = s;
	/* analog output subdevice (loopback) */
	s->type = COMEDI_SUBD_AO;
	s->subdev_flags = SDF_WRITEABLE | SDF_GROUND;
	s->n_chan = thisboard->ai_chans;
	s->maxdata = (1 << thisboard->ai_bits) - 1;
	s->range_table = &waveform_ai_ranges;
	s->len_chanlist = s->n_chan * 2;
	s->insn_write = waveform_ao_insn_write; 
	s->do_cmd = 0;
	s->do_cmdtest = 0;
	s->cancel = 0;
	{
		/* Our default loopback value is just a 0V flatline */
		int i;
		for (i = 0; i < s->n_chan; i++) 
			devpriv->ao_loopbacks[i] = s->maxdata / 2;
	}

	init_timer(&(devpriv->timer));
	devpriv->timer.function = waveform_ai_interrupt;
	devpriv->timer.data = (unsigned long) dev;

	printk("attached\n");

	return 1;
}

static int waveform_detach(comedi_device *dev)
{
	printk("comedi%d: comedi_test: remove\n",dev->minor);

	if(dev->private)
	{
		waveform_ai_cancel(dev, dev->read_subdev);
	}

	return 0;
}

static int waveform_ai_cmdtest(comedi_device *dev,comedi_subdevice *s,
	comedi_cmd *cmd)
{
	int err = 0;
	int tmp;

	/* step 1: make sure trigger sources are trivially valid */

	tmp = cmd->start_src;
	cmd->start_src &= TRIG_NOW;
	if(!cmd->start_src || tmp != cmd->start_src) err++;

	tmp = cmd->scan_begin_src;
	cmd->scan_begin_src &= TRIG_TIMER;
	if(!cmd->scan_begin_src || tmp != cmd->scan_begin_src) err++;

	tmp = cmd->convert_src;
	cmd->convert_src &= TRIG_NOW | TRIG_TIMER;
	if(!cmd->convert_src || tmp != cmd->convert_src) err++;

	tmp = cmd->scan_end_src;
	cmd->scan_end_src &= TRIG_COUNT;
	if(!cmd->scan_end_src || tmp != cmd->scan_end_src) err++;

	tmp=cmd->stop_src;
	cmd->stop_src &= TRIG_COUNT | TRIG_NONE;
	if(!cmd->stop_src || tmp!=cmd->stop_src) err++;

	if(err) return 1;

	/* step 2: make sure trigger sources are unique and mutually compatible */

	if(cmd->convert_src != TRIG_NOW &&
		cmd->convert_src != TRIG_TIMER) err++;
	if(cmd->stop_src != TRIG_COUNT &&
		cmd->stop_src != TRIG_NONE) err++;

	if(err)return 2;

	/* step 3: make sure arguments are trivially compatible */

	if(cmd->start_arg != 0)
	{
		cmd->start_arg = 0;
		err++;
	}
	if(cmd->convert_src == TRIG_NOW)
	{
		if(cmd->convert_arg != 0)
		{
			cmd->convert_arg = 0;
			err++;
		}
	}
	if(cmd->scan_begin_src == TRIG_TIMER)
	{
		if(cmd->scan_begin_arg < nano_per_micro)
		{
			cmd->scan_begin_arg = nano_per_micro;
			err++;
		}
		if(cmd->convert_src == TRIG_TIMER &&
			cmd->scan_begin_arg < cmd->convert_arg * cmd->chanlist_len)
		{
			cmd->scan_begin_arg = cmd->convert_arg * cmd->chanlist_len;
			err++;
		}
	}


	// XXX these checks are generic and should go in core if not there already
	if(!cmd->chanlist_len)
	{
		cmd->chanlist_len = 1;
		err++;
	}
	if(cmd->scan_end_arg != cmd->chanlist_len)
	{
		cmd->scan_end_arg = cmd->chanlist_len;
		err++;
	}

	if(cmd->stop_src == TRIG_COUNT)
	{
		if(!cmd->stop_arg)
		{
			cmd->stop_arg = 1;
			err++;
		}
	} else
	{ /* TRIG_NONE */
		if(cmd->stop_arg != 0)
		{
			cmd->stop_arg = 0;
			err++;
		}
	}

	if(err)return 3;

	/* step 4: fix up any arguments */

	if(cmd->scan_begin_src == TRIG_TIMER)
	{
		tmp = cmd->scan_begin_arg;
		// round to nearest microsec
		cmd->scan_begin_arg = nano_per_micro * ((tmp + (nano_per_micro / 2)) / nano_per_micro);
		if(tmp != cmd->scan_begin_arg) err++;
	}
	if(cmd->convert_src == TRIG_TIMER)
	{
		tmp = cmd->convert_arg;
		// round to nearest microsec
		cmd->convert_arg = nano_per_micro * ((tmp + (nano_per_micro / 2)) / nano_per_micro);
		if(tmp != cmd->convert_arg) err++;
	}

	if(err) return 4;

	return 0;
}

static int waveform_ai_cmd(comedi_device *dev, comedi_subdevice *s)
{
	comedi_cmd *cmd = &s->async->cmd;

	if( cmd->flags & TRIG_RT )
	{
		comedi_error( dev, "commands at RT priority not supported in this driver" );
		return -1;
	}

	devpriv->timer_running = 1;
	devpriv->ai_count = 0;
	devpriv->scan_period = cmd->scan_begin_arg / nano_per_micro;

	if(cmd->convert_src == TRIG_NOW)
		devpriv->convert_period = 0;
	else if( cmd->convert_src == TRIG_TIMER)
		devpriv->convert_period = cmd->convert_arg / nano_per_micro;
	else
	{
		comedi_error(dev, "bug setting conversion period");
		return -1;
	}

	do_gettimeofday(&devpriv->last);
	devpriv->usec_current = devpriv->last.tv_usec % devpriv->usec_period;
	devpriv->usec_remainder = 0;

	devpriv->timer.expires = jiffies + 1;
	add_timer(&devpriv->timer);
	return 0;
}

static int waveform_ai_cancel(comedi_device *dev, comedi_subdevice *s)
{
	devpriv->timer_running = 0;
	del_timer(&devpriv->timer);
	return 0;
}

static sampl_t fake_sawtooth(comedi_device *dev, unsigned int range_index, unsigned long current_time)
{
	comedi_subdevice *s = dev->read_subdev;
	unsigned int offset = s->maxdata / 2;
	u64 value;
	comedi_krange *krange = &s->range_table->range[range_index];
	u64 binary_amplitude;

	binary_amplitude = s->maxdata;
	binary_amplitude *= devpriv->uvolt_amplitude;
	do_div(binary_amplitude, krange->max - krange->min);

	current_time %= devpriv->usec_period;
	value = current_time;
	value *= binary_amplitude * 2;
	do_div(value, devpriv->usec_period);
	value -= binary_amplitude;	// get rid of sawtooth's dc offset

	return offset + value;
}
static sampl_t fake_squarewave(comedi_device *dev, unsigned int range_index, unsigned long current_time)
{
	comedi_subdevice *s = dev->read_subdev;
	unsigned int offset = s->maxdata / 2;
	u64 value;
	comedi_krange *krange = &s->range_table->range[range_index];
	current_time %= devpriv->usec_period;

	value = s->maxdata;
	value *= devpriv->uvolt_amplitude;
	do_div(value, krange->max - krange->min);

	if(current_time < devpriv->usec_period / 2)
		value *= -1;

	return offset + value;
}

static sampl_t fake_flatline(comedi_device *dev, unsigned int range_index, unsigned long current_time)
{
	return dev->read_subdev->maxdata / 2;
}

// generates a different waveform depending on what channel is read
static sampl_t fake_waveform(comedi_device *dev, unsigned int channel,
	unsigned int range, unsigned long current_time)
{
	enum
	{
		SAWTOOTH_CHAN,
		SQUARE_CHAN,
	};
	switch(channel)
	{
		case SAWTOOTH_CHAN:
			return fake_sawtooth(dev, range, current_time);
			break;
		case SQUARE_CHAN:
			return fake_squarewave(dev, range, current_time);
			break;
		default:
			break;
	}

	return fake_flatline(dev, range, current_time);
}

static int waveform_ai_insn_read(comedi_device *dev, comedi_subdevice *s, comedi_insn *insn, lsampl_t *data)
{
	int i, chan = CR_CHAN(insn->chanspec);

	for(i = 0; i < insn->n; i++)
		data[i] = devpriv->ao_loopbacks[chan];

	return insn->n;
}

static int waveform_ao_insn_write(comedi_device *dev, comedi_subdevice *s, comedi_insn *insn, lsampl_t *data)
{
	int i, chan = CR_CHAN(insn->chanspec);
	
	for(i = 0; i < insn->n; i++)
		devpriv->ao_loopbacks[chan] = data[i];

	return insn->n;
}