一个典型的字符设备驱动,带平台设备与驱动注册

长平狐 发布于 2012/06/12 15:32
阅读 247
收藏 0
/*
 * Advantech Single Board Computer WDT driver
 *
 * (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
 *
 * Based on acquirewdt.c which is based on wdt.c.
 * Original copyright messages:
 *
 * (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
 * All Rights Reserved.
 *
 * 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.
 *
 * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
 * warranty for any of this software. This material is provided
 * "AS-IS" and at no charge.
 *
 * (c) Copyright 1995    Alan Cox <alan@lxorguk.ukuu.org.uk>
 *
 * 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
 *    Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
 *
 * 16-Oct-2002 Rob Radez <rob@osinvestor.com>
 *    Clean up ioctls, clean up init + exit, add expect close support,
 *    add wdt_start and wdt_stop as parameters.
 */


#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/fs.h>
#include <linux/ioport.h>
#include <linux/platform_device.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/uaccess.h>


#include <asm/system.h>


#define DRV_NAME "advantechwdt"
#define PFX DRV_NAME ": "
#define WATCHDOG_NAME "Advantech WDT"
#define WATCHDOG_TIMEOUT 60 /* 60 sec default timeout */


/* the watchdog platform device */
static struct platform_device *advwdt_platform_device;
static unsigned long advwdt_is_open;
static char adv_expect_close;


/*
 * You must set these - there is no sane way to probe for this board.
 *
 * To enable or restart, write the timeout value in seconds (1 to 63)
 * to I/O port wdt_start.  To disable, read I/O port wdt_stop.
 * Both are 0x443 for most boards (tested on a PCA-6276VE-00B1), but
 * check your manual (at least the PCA-6159 seems to be different -
 * the manual says wdt_stop is 0x43, not 0x443).
 * (0x43 is also a write-only control register for the 8254 timer!)
 */


static int wdt_stop = 0x443;
module_param(wdt_stop, int, 0);
MODULE_PARM_DESC(wdt_stop, "Advantech WDT 'stop' io port (default 0x443)");


static int wdt_start = 0x443;
module_param(wdt_start, int, 0);
MODULE_PARM_DESC(wdt_start, "Advantech WDT 'start' io port (default 0x443)");


static int timeout = WATCHDOG_TIMEOUT; /* in seconds */
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout,
"Watchdog timeout in seconds. 1<= timeout <=63, default="
__MODULE_STRING(WATCHDOG_TIMEOUT) ".");


static int nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout,
"Watchdog cannot be stopped once started (default="
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");


/*
 * Watchdog Operations
 */


static void advwdt_ping(void)
{
/* Write a watchdog value */
outb_p(timeout, wdt_start);
}


static void advwdt_disable(void)
{
inb_p(wdt_stop);
}


static int advwdt_set_heartbeat(int t)
{
if (t < 1 || t > 63)
return -EINVAL;
timeout = t;
return 0;
}


/*
 * /dev/watchdog handling
 */


static ssize_t advwdt_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
if (count) {
if (!nowayout) {
size_t i;


adv_expect_close = 0;


for (i = 0; i != count; i++) {
char c;
if (get_user(c, buf + i))
return -EFAULT;
if (c == 'V')
adv_expect_close = 42;
}
}
advwdt_ping();
}
return count;
}


static long advwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
int new_timeout;
void __user *argp = (void __user *)arg;
int __user *p = argp;
static struct watchdog_info ident = {
.options = WDIOF_KEEPALIVEPING |
  WDIOF_SETTIMEOUT |
  WDIOF_MAGICCLOSE,
.firmware_version = 1,
.identity = WATCHDOG_NAME,
};


switch (cmd) {
case WDIOC_GETSUPPORT:
if (copy_to_user(argp, &ident, sizeof(ident)))
return -EFAULT;
break;


case WDIOC_GETSTATUS:
case WDIOC_GETBOOTSTATUS:
return put_user(0, p);


case WDIOC_SETOPTIONS:
{
int options, retval = -EINVAL;


if (get_user(options, p))
return -EFAULT;
if (options & WDIOS_DISABLECARD) {
advwdt_disable();
retval = 0;
}
if (options & WDIOS_ENABLECARD) {
advwdt_ping();
retval = 0;
}
return retval;
}
case WDIOC_KEEPALIVE:
advwdt_ping();
break;


case WDIOC_SETTIMEOUT:
if (get_user(new_timeout, p))
return -EFAULT;
if (advwdt_set_heartbeat(new_timeout))
return -EINVAL;
advwdt_ping();
/* Fall */
case WDIOC_GETTIMEOUT:
return put_user(timeout, p);
default:
return -ENOTTY;
}
return 0;
}


static int advwdt_open(struct inode *inode, struct file *file)
{
if (test_and_set_bit(0, &advwdt_is_open))
return -EBUSY;
/*
* Activate
*/


advwdt_ping();
return nonseekable_open(inode, file);
}


static int advwdt_close(struct inode *inode, struct file *file)
{
if (adv_expect_close == 42) {
advwdt_disable();
} else {
printk(KERN_CRIT PFX
"Unexpected close, not stopping watchdog!\n");
advwdt_ping();
}
clear_bit(0, &advwdt_is_open);
adv_expect_close = 0;
return 0;
}


/*
 * Kernel Interfaces
 */


static const struct file_operations advwdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = advwdt_write,
.unlocked_ioctl = advwdt_ioctl,
.open = advwdt_open,
.release = advwdt_close,
};


static struct miscdevice advwdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &advwdt_fops,
};


/*
 * Init & exit routines
 */


static int __devinit advwdt_probe(struct platform_device *dev)
{
int ret;


if (wdt_stop != wdt_start) {
if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) {
printk(KERN_ERR PFX
"I/O address 0x%04x already in use\n",
wdt_stop);
ret = -EIO;
goto out;
}
}


if (!request_region(wdt_start, 1, WATCHDOG_NAME)) {
printk(KERN_ERR PFX
"I/O address 0x%04x already in use\n",
wdt_start);
ret = -EIO;
goto unreg_stop;
}


/* Check that the heartbeat value is within it's range ;
* if not reset to the default */
if (advwdt_set_heartbeat(timeout)) {
advwdt_set_heartbeat(WATCHDOG_TIMEOUT);
printk(KERN_INFO PFX
"timeout value must be 1<=x<=63, using %d\n", timeout);
}


ret = misc_register(&advwdt_miscdev);
if (ret != 0) {
printk(KERN_ERR PFX
"cannot register miscdev on minor=%d (err=%d)\n",
WATCHDOG_MINOR, ret);
goto unreg_regions;
}
printk(KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n",
timeout, nowayout);
out:
return ret;
unreg_regions:
release_region(wdt_start, 1);
unreg_stop:
if (wdt_stop != wdt_start)
release_region(wdt_stop, 1);
goto out;
}


static int __devexit advwdt_remove(struct platform_device *dev)
{
misc_deregister(&advwdt_miscdev);
release_region(wdt_start, 1);
if (wdt_stop != wdt_start)
release_region(wdt_stop, 1);


return 0;
}


static void advwdt_shutdown(struct platform_device *dev)
{
/* Turn the WDT off if we have a soft shutdown */
advwdt_disable();
}


static struct platform_driver advwdt_driver = {
.probe = advwdt_probe,
.remove = __devexit_p(advwdt_remove),
.shutdown = advwdt_shutdown,
.driver = {
.owner = THIS_MODULE,
.name = DRV_NAME,
},
};


static int __init advwdt_init(void)
{
int err;


printk(KERN_INFO
    "WDT driver for Advantech single board computer initialising.\n");


err = platform_driver_register(&advwdt_driver);
if (err)
return err;


advwdt_platform_device = platform_device_register_simple(DRV_NAME,
-1, NULL, 0);
if (IS_ERR(advwdt_platform_device)) {
err = PTR_ERR(advwdt_platform_device);
goto unreg_platform_driver;
}


return 0;


unreg_platform_driver:
platform_driver_unregister(&advwdt_driver);
return err;
}


static void __exit advwdt_exit(void)
{
platform_device_unregister(advwdt_platform_device);
platform_driver_unregister(&advwdt_driver);
printk(KERN_INFO PFX "Watchdog Module Unloaded.\n");
}


module_init(advwdt_init);
module_exit(advwdt_exit);


MODULE_LICENSE("GPL");
MODULE_AUTHOR("Marek Michalkiewicz <marekm@linux.org.pl>");
MODULE_DESCRIPTION("Advantech Single Board Computer WDT driver");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
原文链接:http://blog.csdn.net/lanmanck/article/details/6612707
加载中
返回顶部
顶部