/*
    comedi/drivers/comedi_test.c

    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 <Joachim.Wuttke@icn.siemens.de>
    Copyright (C) 2002 Frank Mori Hess <fmhess@users.sourceforge.net>

    COMEDI - Linux Control and Measurement Device Interface
    Copyright (C) 2000 David A. Schleef <ds@schleef.org>

    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
Description: generates fake waveforms
Author: Joachim Wuttke <Joachim.Wuttke@icn.siemens.de>, Frank Mori Hess
  <fmhess@users.sourceforge.net>, 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 "../comedidev.h"

#include <asm/div64.h>

#include "comedi_fc.h"
#include <linux/timer.h>

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

#define N_CHANS 8

static const struct waveform_board waveform_boards[] = {
        {
         .name = "comedi_test",
         .ai_chans = N_CHANS,
         .ai_bits = 16,
         .have_dio = 0,
         },
};

#define thisboard ((const struct waveform_board *)dev->board_ptr)

/* Data unique to this driver */
struct waveform_private {
        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 */
        unsigned long usec_current;     /* current time (modulo waveform period) */
        unsigned long usec_remainder;   /* usec since last scan; */
        unsigned long ai_count; /* number of conversions remaining */
        unsigned int scan_period;       /* scan period in usec */
        unsigned int convert_period;    /* conversion period in usec */
        unsigned timer_running:1;
        unsigned int ao_loopbacks[N_CHANS];
};
#define devpriv ((struct waveform_private *)dev->private)

static int waveform_attach(struct comedi_device *dev,
                           struct comedi_devconfig *it);
static int waveform_detach(struct comedi_device *dev);
static struct comedi_driver driver_waveform = {
        .driver_name = "comedi_test",
        .module = THIS_MODULE,
        .attach = waveform_attach,
        .detach = waveform_detach,
        .board_name = &waveform_boards[0].name,
        .offset = sizeof(struct waveform_board),
        .num_names = ARRAY_SIZE(waveform_boards),
};

COMEDI_INITCLEANUP(driver_waveform);

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

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

/* fake analog input ranges */
static const struct 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)
{
        struct comedi_device *dev = (struct comedi_device *)arg;
        struct comedi_async *async = dev->read_subdev->async;
        struct 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);
}

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

        dev->board_name = thisboard->name;

        if (alloc_private(dev, sizeof(struct 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;

        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 | SDF_CMD_READ;
        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;
        s->do_cmd = waveform_ai_cmd;
        s->do_cmdtest = waveform_ai_cmdtest;
        s->cancel = waveform_ai_cancel;

        s = dev->subdevices + 1;
        dev->write_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 = NULL;
        s->do_cmdtest = NULL;
        s->cancel = NULL;

        /* Our default loopback value is just a 0V flatline */
        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(KERN_INFO "comedi%d: comedi_test: "
               "%i microvolt, %li microsecond waveform attached\n", dev->minor,
               devpriv->uvolt_amplitude, devpriv->usec_period);
        return 1;
}

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

static short fake_sawtooth(struct comedi_device *dev, unsigned int range_index,
                           unsigned long current_time)
{
        struct comedi_subdevice *s = dev->read_subdev;
        unsigned int offset = s->maxdata / 2;
        u64 value;
        const struct 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 short fake_squarewave(struct comedi_device *dev,
                             unsigned int range_index,
                             unsigned long current_time)
{
        struct comedi_subdevice *s = dev->read_subdev;
        unsigned int offset = s->maxdata / 2;
        u64 value;
        const struct 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 short fake_flatline(struct 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 short fake_waveform(struct 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(struct comedi_device *dev,
                                 struct comedi_subdevice *s,
                                 struct comedi_insn *insn, unsigned int *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(struct comedi_device *dev,
                                  struct comedi_subdevice *s,
                                  struct comedi_insn *insn, unsigned int *data)
{
        int i, chan = CR_CHAN(insn->chanspec);

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

        return insn->n;
}