/*
 * kcomedilib/kcomedilib.c
 * a comedlib interface for kernel modules
 *
 * COMEDI - Linux Control and Measurement Device Interface
 * Copyright (C) 1997-2000 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.
 */

#include <linux/module.h>

#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/io.h>

#include "../comedi.h"
#include "../comedilib.h"
#include "../comedidev.h"

MODULE_AUTHOR("David Schleef <ds@schleef.org>");
MODULE_DESCRIPTION("Comedi kernel library");
MODULE_LICENSE("GPL");

struct comedi_device *comedi_open(const char *filename)
{
        struct comedi_device *dev, *retval = NULL;
        unsigned int minor;

        if (strncmp(filename, "/dev/comedi", 11) != 0)
                return NULL;

        if (kstrtouint(filename + 11, 0, &minor))
                return NULL;

        if (minor >= COMEDI_NUM_BOARD_MINORS)
                return NULL;

        dev = comedi_dev_get_from_minor(minor);
        if (!dev)
                return NULL;

        down_read(&dev->attach_lock);
        if (dev->attached)
                retval = dev;
        else
                retval = NULL;
        up_read(&dev->attach_lock);

        if (!retval)
                comedi_dev_put(dev);

        return retval;
}
EXPORT_SYMBOL_GPL(comedi_open);

int comedi_close(struct comedi_device *dev)
{
        comedi_dev_put(dev);
        return 0;
}
EXPORT_SYMBOL_GPL(comedi_close);

static int comedi_do_insn(struct comedi_device *dev,
                          struct comedi_insn *insn,
                          unsigned int *data)
{
        struct comedi_subdevice *s;
        int ret;

        mutex_lock(&dev->mutex);

        if (!dev->attached) {
                ret = -EINVAL;
                goto error;
        }

        /* a subdevice instruction */
        if (insn->subdev >= dev->n_subdevices) {
                ret = -EINVAL;
                goto error;
        }
        s = &dev->subdevices[insn->subdev];

        if (s->type == COMEDI_SUBD_UNUSED) {
                dev_err(dev->class_dev,
                        "%d not usable subdevice\n", insn->subdev);
                ret = -EIO;
                goto error;
        }

        /* XXX check lock */

        ret = comedi_check_chanlist(s, 1, &insn->chanspec);
        if (ret < 0) {
                dev_err(dev->class_dev, "bad chanspec\n");
                ret = -EINVAL;
                goto error;
        }

        if (s->busy) {
                ret = -EBUSY;
                goto error;
        }
        s->busy = dev;

        switch (insn->insn) {
        case INSN_BITS:
                ret = s->insn_bits(dev, s, insn, data);
                break;
        case INSN_CONFIG:
                /* XXX should check instruction length */
                ret = s->insn_config(dev, s, insn, data);
                break;
        default:
                ret = -EINVAL;
                break;
        }

        s->busy = NULL;
error:

        mutex_unlock(&dev->mutex);
        return ret;
}

int comedi_dio_get_config(struct comedi_device *dev, unsigned int subdev,
                          unsigned int chan, unsigned int *io)
{
        struct comedi_insn insn;
        unsigned int data[2];
        int ret;

        memset(&insn, 0, sizeof(insn));
        insn.insn = INSN_CONFIG;
        insn.n = 2;
        insn.subdev = subdev;
        insn.chanspec = CR_PACK(chan, 0, 0);
        data[0] = INSN_CONFIG_DIO_QUERY;
        data[1] = 0;
        ret = comedi_do_insn(dev, &insn, data);
        if (ret >= 0)
                *io = data[1];
        return ret;
}
EXPORT_SYMBOL_GPL(comedi_dio_get_config);

int comedi_dio_config(struct comedi_device *dev, unsigned int subdev,
                      unsigned int chan, unsigned int io)
{
        struct comedi_insn insn;

        memset(&insn, 0, sizeof(insn));
        insn.insn = INSN_CONFIG;
        insn.n = 1;
        insn.subdev = subdev;
        insn.chanspec = CR_PACK(chan, 0, 0);

        return comedi_do_insn(dev, &insn, &io);
}
EXPORT_SYMBOL_GPL(comedi_dio_config);

int comedi_dio_bitfield2(struct comedi_device *dev, unsigned int subdev,
                         unsigned int mask, unsigned int *bits,
                         unsigned int base_channel)
{
        struct comedi_insn insn;
        unsigned int data[2];
        unsigned int n_chan;
        unsigned int shift;
        int ret;

        base_channel = CR_CHAN(base_channel);
        n_chan = comedi_get_n_channels(dev, subdev);
        if (base_channel >= n_chan)
                return -EINVAL;

        memset(&insn, 0, sizeof(insn));
        insn.insn = INSN_BITS;
        insn.chanspec = base_channel;
        insn.n = 2;
        insn.subdev = subdev;

        data[0] = mask;
        data[1] = *bits;

        /*
         * Most drivers ignore the base channel in insn->chanspec.
         * Fix this here if the subdevice has <= 32 channels.
         */
        if (n_chan <= 32) {
                shift = base_channel;
                if (shift) {
                        insn.chanspec = 0;
                        data[0] <<= shift;
                        data[1] <<= shift;
                }
        } else {
                shift = 0;
        }

        ret = comedi_do_insn(dev, &insn, data);
        *bits = data[1] >> shift;
        return ret;
}
EXPORT_SYMBOL_GPL(comedi_dio_bitfield2);

int comedi_find_subdevice_by_type(struct comedi_device *dev, int type,
                                  unsigned int subd)
{
        struct comedi_subdevice *s;
        int ret = -ENODEV;

        down_read(&dev->attach_lock);
        if (dev->attached)
                for (; subd < dev->n_subdevices; subd++) {
                        s = &dev->subdevices[subd];
                        if (s->type == type) {
                                ret = subd;
                                break;
                        }
                }
        up_read(&dev->attach_lock);
        return ret;
}
EXPORT_SYMBOL_GPL(comedi_find_subdevice_by_type);

int comedi_get_n_channels(struct comedi_device *dev, unsigned int subdevice)
{
        int n;

        down_read(&dev->attach_lock);
        if (!dev->attached || subdevice >= dev->n_subdevices)
                n = 0;
        else
                n = dev->subdevices[subdevice].n_chan;
        up_read(&dev->attach_lock);

        return n;
}
EXPORT_SYMBOL_GPL(comedi_get_n_channels);