comedi_fops.c - Android社区 - https://www.androidos.net.cn/

Kernel | 3.10

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/*
    comedi/comedi_fops.c
    comedi kernel module

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.

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.

#undef DEBUG

#include "comedi_compat32.h"

#include <linux/module.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/fcntl.h>
#include <linux/delay.h>
#include <linux/ioport.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/kmod.h>
#include <linux/poll.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/vmalloc.h>
#include <linux/fs.h>
#include "comedidev.h"
#include <linux/cdev.h>
#include <linux/stat.h>

#include <linux/io.h>
#include <linux/uaccess.h>

#include "comedi_internal.h"

#define COMEDI_NUM_MINORS 0x100
#define COMEDI_NUM_SUBDEVICE_MINORS	\
	(COMEDI_NUM_MINORS - COMEDI_NUM_BOARD_MINORS)

#ifdef CONFIG_COMEDI_DEBUG
int comedi_debug;
EXPORT_SYMBOL_GPL(comedi_debug);
module_param(comedi_debug, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(comedi_debug,
		 "enable comedi core and driver debugging if non-zero (default 0)"
		);
#endif

static int comedi_num_legacy_minors;
module_param(comedi_num_legacy_minors, int, S_IRUGO);
MODULE_PARM_DESC(comedi_num_legacy_minors,
		 "number of comedi minor devices to reserve for non-auto-configured devices (default 0)"
		);

unsigned int comedi_default_buf_size_kb = CONFIG_COMEDI_DEFAULT_BUF_SIZE_KB;
module_param(comedi_default_buf_size_kb, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(comedi_default_buf_size_kb,
		 "default asynchronous buffer size in KiB (default "
		 __MODULE_STRING(CONFIG_COMEDI_DEFAULT_BUF_SIZE_KB) ")");

unsigned int comedi_default_buf_maxsize_kb
	= CONFIG_COMEDI_DEFAULT_BUF_MAXSIZE_KB;
module_param(comedi_default_buf_maxsize_kb, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(comedi_default_buf_maxsize_kb,
		 "default maximum size of asynchronous buffer in KiB (default "
		 __MODULE_STRING(CONFIG_COMEDI_DEFAULT_BUF_MAXSIZE_KB) ")");

static DEFINE_MUTEX(comedi_board_minor_table_lock);
static struct comedi_device
*comedi_board_minor_table[COMEDI_NUM_BOARD_MINORS];

static DEFINE_MUTEX(comedi_subdevice_minor_table_lock);
/* Note: indexed by minor - COMEDI_NUM_BOARD_MINORS. */
static struct comedi_subdevice
*comedi_subdevice_minor_table[COMEDI_NUM_SUBDEVICE_MINORS];

static struct class *comedi_class;
static struct cdev comedi_cdev;

static void comedi_device_init(struct comedi_device *dev)
{
	spin_lock_init(&dev->spinlock);
	mutex_init(&dev->mutex);
	dev->minor = -1;
}

static void comedi_device_cleanup(struct comedi_device *dev)
{
	struct module *driver_module = NULL;

if (dev == NULL)
		return;
	mutex_lock(&dev->mutex);
	if (dev->attached)
		driver_module = dev->driver->module;
	comedi_device_detach(dev);
	while (dev->use_count > 0) {
		if (driver_module)
			module_put(driver_module);
		module_put(THIS_MODULE);
		dev->use_count--;
	}
	mutex_unlock(&dev->mutex);
	mutex_destroy(&dev->mutex);
}

static bool comedi_clear_board_dev(struct comedi_device *dev)
{
	unsigned int i = dev->minor;
	bool cleared = false;

mutex_lock(&comedi_board_minor_table_lock);
	if (dev == comedi_board_minor_table[i]) {
		comedi_board_minor_table[i] = NULL;
		cleared = true;
	}
	mutex_unlock(&comedi_board_minor_table_lock);
	return cleared;
}

static struct comedi_device *comedi_clear_board_minor(unsigned minor)
{
	struct comedi_device *dev;

mutex_lock(&comedi_board_minor_table_lock);
	dev = comedi_board_minor_table[minor];
	comedi_board_minor_table[minor] = NULL;
	mutex_unlock(&comedi_board_minor_table_lock);
	return dev;
}

static void comedi_free_board_dev(struct comedi_device *dev)
{
	if (dev) {
		if (dev->class_dev) {
			device_destroy(comedi_class,
				       MKDEV(COMEDI_MAJOR, dev->minor));
		}
		comedi_device_cleanup(dev);
		kfree(dev);
	}
}

static struct comedi_subdevice
*comedi_subdevice_from_minor(unsigned minor)
{
	struct comedi_subdevice *s;
	unsigned int i = minor - COMEDI_NUM_BOARD_MINORS;

BUG_ON(i >= COMEDI_NUM_SUBDEVICE_MINORS);
	mutex_lock(&comedi_subdevice_minor_table_lock);
	s = comedi_subdevice_minor_table[i];
	mutex_unlock(&comedi_subdevice_minor_table_lock);
	return s;
}

static struct comedi_device *comedi_dev_from_board_minor(unsigned minor)
{
	struct comedi_device *dev;

BUG_ON(minor >= COMEDI_NUM_BOARD_MINORS);
	mutex_lock(&comedi_board_minor_table_lock);
	dev = comedi_board_minor_table[minor];
	mutex_unlock(&comedi_board_minor_table_lock);
	return dev;
}

static struct comedi_device *comedi_dev_from_subdevice_minor(unsigned minor)
{
	struct comedi_subdevice *s;

s = comedi_subdevice_from_minor(minor);
	return s ? s->device : NULL;
}

struct comedi_device *comedi_dev_from_minor(unsigned minor)
{
	if (minor < COMEDI_NUM_BOARD_MINORS)
		return comedi_dev_from_board_minor(minor);
	else
		return comedi_dev_from_subdevice_minor(minor);
}
EXPORT_SYMBOL_GPL(comedi_dev_from_minor);

static struct comedi_subdevice *
comedi_read_subdevice(const struct comedi_device *dev, unsigned int minor)
{
	struct comedi_subdevice *s;

if (minor >= COMEDI_NUM_BOARD_MINORS) {
		s = comedi_subdevice_from_minor(minor);
		if (!s || s->device != dev)
			return NULL;
		if (s->subdev_flags & SDF_CMD_READ)
			return s;
	}
	return dev->read_subdev;
}

static struct comedi_subdevice *
comedi_write_subdevice(const struct comedi_device *dev, unsigned int minor)
{
	struct comedi_subdevice *s;

if (minor >= COMEDI_NUM_BOARD_MINORS) {
		s = comedi_subdevice_from_minor(minor);
		if (!s || s->device != dev)
			return NULL;
		if (s->subdev_flags & SDF_CMD_WRITE)
			return s;
	}
	return dev->write_subdev;
}

static int resize_async_buffer(struct comedi_device *dev,
			       struct comedi_subdevice *s,
			       struct comedi_async *async, unsigned new_size)
{
	int retval;

if (new_size > async->max_bufsize)
		return -EPERM;

if (s->busy) {
		DPRINTK("subdevice is busy, cannot resize buffer\n");
		return -EBUSY;
	}
	if (async->mmap_count) {
		DPRINTK("subdevice is mmapped, cannot resize buffer\n");
		return -EBUSY;
	}

/* make sure buffer is an integral number of pages
	 * (we round up) */
	new_size = (new_size + PAGE_SIZE - 1) & PAGE_MASK;

retval = comedi_buf_alloc(dev, s, new_size);
	if (retval < 0)
		return retval;

if (s->buf_change) {
		retval = s->buf_change(dev, s, new_size);
		if (retval < 0)
			return retval;
	}

DPRINTK("comedi%i subd %d buffer resized to %i bytes\n",
		dev->minor, s->index, async->prealloc_bufsz);
	return 0;
}

/* sysfs attribute files */

static ssize_t show_max_read_buffer_kb(struct device *csdev,
				       struct device_attribute *attr, char *buf)
{
	unsigned int minor = MINOR(csdev->devt);
	struct comedi_device *dev;
	struct comedi_subdevice *s;
	unsigned int size = 0;