taskwatch.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 195 行

/*
 * linux/arch/arm/mach-omap/dsp/taskwatch.c
 *
 * OMAP DSP task watch device driver
 *
 * Copyright (C) 2002-2004 Nokia Corporation
 *
 * Written by Toshihiro Kobayashi <[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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 * $Id: taskwatch.c
 * $Revision: 3.0.1
 * $Date: 2004/10/04
 *
 */

#include <linux/module.h>
#include <linux/major.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/poll.h>
#include <linux/interrupt.h>
#include <linux/sched.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include <asm/arch/dsp.h>
#include "dsp.h"

static wait_queue_head_t read_wait_q;
static struct semaphore ioctl_sem;
static unsigned char n_task_base;
static int cfgstat = CFGSTAT_ERR;
static unsigned int change_cnt;

void omap_dsp_twch_touch(void)
{
	change_cnt++;
	wake_up_interruptible(&read_wait_q);
}

/*
 * @count: represents the device counts of the user's interst
 */
static ssize_t omap_dsp_twch_read(struct file *file, char *buf,
				  size_t count, loff_t *ppos)
{
	char taskstat[TASKDEV_MAX];
	int i;

	if (cfgstat != CFGSTAT_DONE) {
		printk(KERN_ERR "omapdsp: dsp has not been configured.\n");
		return -EINVAL;
	}

	if (change_cnt == 0) {
		long current_state;
		DECLARE_WAITQUEUE(wait, current);

		add_wait_queue(&read_wait_q, &wait);
		current_state = current->state;
		set_current_state(TASK_INTERRUPTIBLE);
		if (change_cnt == 0)	/* last check */
			schedule();
		set_current_state(current_state);
		remove_wait_queue(&read_wait_q, &wait);

		/* unconfigured while waiting ;-( */
		if (cfgstat != CFGSTAT_DONE)
			return -EINVAL;
	}

	if (count > TASKDEV_MAX)
		count = TASKDEV_MAX;
	memset(taskstat, OMAP_DSP_OPENSTAT_CLOSE, count);

	change_cnt = 0;
	for (i = n_task_base; i < count; i++) {
		taskstat[i] = omap_dsp_taskdev_openstat(i);
	}

	if (copy_to_user(buf, taskstat, count))
		return -EFAULT;

	return count;
}

static unsigned int omap_dsp_twch_poll(struct file *file, poll_table *wait)
{
	unsigned int mask = 0;

	poll_wait(file, &read_wait_q, wait);
	if (change_cnt)
		mask |= POLLIN | POLLRDNORM;

	return mask;
}

static int omap_dsp_twch_ioctl(struct inode *inode, struct file *file,
			       unsigned int cmd, unsigned long arg)
{
	int sem_st, ret;

	if ((sem_st = down_interruptible(&ioctl_sem)) < 0)
		return sem_st;

	switch (cmd) {
	case OMAP_DSP_TWCH_IOCTL_MKDEV:
		{
			char name[OMAP_DSP_TNM_LEN];
			if (copy_from_user(name, (void *)arg, OMAP_DSP_TNM_LEN)) {
				ret = -EFAULT;
				goto finish;
			}
			ret = omap_dsp_mkdev(name);
			break;
		}

	case OMAP_DSP_TWCH_IOCTL_RMDEV:
		{
			char name[OMAP_DSP_TNM_LEN];
			if (copy_from_user(name, (void *)arg, OMAP_DSP_TNM_LEN)) {
				ret = -EFAULT;
				goto finish;
			}
			ret = omap_dsp_rmdev(name);
			break;
		}

	case OMAP_DSP_TWCH_IOCTL_TADD:
		{
			struct omap_dsp_taddinfo ti;
			if (copy_from_user(&ti, (void *)arg, sizeof(ti))) {
				ret = -EFAULT;
				goto finish;
			}
			ret = omap_dsp_tadd(ti.minor, ti.taskadr);
			break;
		}

	case OMAP_DSP_TWCH_IOCTL_TDEL:
		ret = omap_dsp_tdel(arg);
		break;

	default:
		ret = -ENOIOCTLCMD;
	}

finish:
	up(&ioctl_sem);
	return ret;
}

struct file_operations omap_dsp_twch_fops = {
	.owner = THIS_MODULE,
	.read  = omap_dsp_twch_read,
	.poll  = omap_dsp_twch_poll,
	.ioctl = omap_dsp_twch_ioctl,
};

void omap_dsp_twch_config(unsigned char n)
{
	n_task_base = n;
	cfgstat = CFGSTAT_DONE;
	change_cnt = 1;		/* first read will not wait */
}

void omap_dsp_twch_unconfig(void)
{
	wake_up_interruptible(&read_wait_q);
	cfgstat = CFGSTAT_ERR;
}

void __init omap_dsp_twch_init(void)
{
	init_MUTEX(&ioctl_sem);
	init_waitqueue_head(&read_wait_q);
}

void omap_dsp_twch_exit(void)
{
}