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linux/drivers/watchdog/sbc8360.c
Jean Delvare 487722cf2d watchdog: Get rid of MODULE_ALIAS_MISCDEV statements 
I just can't find any value in MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR)
and MODULE_ALIAS_MISCDEV(TEMP_MINOR) statements.

Either the device is enumerated and the driver already has a module
alias (e.g. PCI, USB etc.) that will get the right driver loaded
automatically.

Or the device is not enumerated and loading its driver will lead to
more or less intrusive hardware poking. Such hardware poking should be
limited to a bare minimum, so the user should really decide which
drivers should be tried and in what order. Trying them all in
arbitrary order can't do any good.

On top of that, loading that many drivers at once bloats the kernel
log. Also many drivers will stay loaded afterward, bloating the output
of "lsmod" and wasting memory. Some modules (cs5535_mfgpt which gets
loaded as a dependency) can't even be unloaded!

If defining char-major-10-130 is needed then it should happen in
user-space.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Mike Frysinger <vapier.adi@gmail.com>
Cc: Wan ZongShun <mcuos.com@gmail.com>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Kukjin Kim <kgene.kim@samsung.com>
Cc: Zwane Mwaikambo <zwane@arm.linux.org.uk>
Cc: Jim Cromie <jim.cromie@gmail.com>
2013-11-17 19:38:13 +01:00

409 lines
9.8 KiB
C
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/*
* SBC8360 Watchdog driver
*
* (c) Copyright 2005 Webcon, Inc.
*
* Based on ib700wdt.c, which is based on advantechwdt.c which is based
* on acquirewdt.c which is based on wdt.c.
*
* (c) Copyright 2001 Charles Howes <chowes@vsol.net>
*
* Based on advantechwdt.c which is based on acquirewdt.c which
* is based on wdt.c.
*
* (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
* Added timeout module option to override default
*
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/types.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/ioport.h>
#include <linux/delay.h>
#include <linux/notifier.h>
#include <linux/fs.h>
#include <linux/reboot.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/moduleparam.h>
#include <linux/io.h>
#include <linux/uaccess.h>
static unsigned long sbc8360_is_open;
static char expect_close;
/*
*
* Watchdog Timer Configuration
*
* The function of the watchdog timer is to reset the system automatically
* and is defined at I/O port 0120H and 0121H. To enable the watchdog timer
* and allow the system to reset, write appropriate values from the table
* below to I/O port 0120H and 0121H. To disable the timer, write a zero
* value to I/O port 0121H for the system to stop the watchdog function.
*
* The following describes how the timer should be programmed (according to
* the vendor documentation)
*
* Enabling Watchdog:
* MOV AX,000AH (enable, phase I)
* MOV DX,0120H
* OUT DX,AX
* MOV AX,000BH (enable, phase II)
* MOV DX,0120H
* OUT DX,AX
* MOV AX,000nH (set multiplier n, from 1-4)
* MOV DX,0120H
* OUT DX,AX
* MOV AX,000mH (set base timer m, from 0-F)
* MOV DX,0121H
* OUT DX,AX
*
* Reset timer:
* MOV AX,000mH (same as set base timer, above)
* MOV DX,0121H
* OUT DX,AX
*
* Disabling Watchdog:
* MOV AX,0000H (a zero value)
* MOV DX,0120H
* OUT DX,AX
*
* Watchdog timeout configuration values:
* N
* M | 1 2 3 4
* --|----------------------------------
* 0 | 0.5s 5s 50s 100s
* 1 | 1s 10s 100s 200s
* 2 | 1.5s 15s 150s 300s
* 3 | 2s 20s 200s 400s
* 4 | 2.5s 25s 250s 500s
* 5 | 3s 30s 300s 600s
* 6 | 3.5s 35s 350s 700s
* 7 | 4s 40s 400s 800s
* 8 | 4.5s 45s 450s 900s
* 9 | 5s 50s 500s 1000s
* A | 5.5s 55s 550s 1100s
* B | 6s 60s 600s 1200s
* C | 6.5s 65s 650s 1300s
* D | 7s 70s 700s 1400s
* E | 7.5s 75s 750s 1500s
* F | 8s 80s 800s 1600s
*
* Another way to say the same things is:
* For N=1, Timeout = (M+1) * 0.5s
* For N=2, Timeout = (M+1) * 5s
* For N=3, Timeout = (M+1) * 50s
* For N=4, Timeout = (M+1) * 100s
*
*/
static int wd_times[64][2] = {
{0, 1}, /* 0 = 0.5s */
{1, 1}, /* 1 = 1s */
{2, 1}, /* 2 = 1.5s */
{3, 1}, /* 3 = 2s */
{4, 1}, /* 4 = 2.5s */
{5, 1}, /* 5 = 3s */
{6, 1}, /* 6 = 3.5s */
{7, 1}, /* 7 = 4s */
{8, 1}, /* 8 = 4.5s */
{9, 1}, /* 9 = 5s */
{0xA, 1}, /* 10 = 5.5s */
{0xB, 1}, /* 11 = 6s */
{0xC, 1}, /* 12 = 6.5s */
{0xD, 1}, /* 13 = 7s */
{0xE, 1}, /* 14 = 7.5s */
{0xF, 1}, /* 15 = 8s */
{0, 2}, /* 16 = 5s */
{1, 2}, /* 17 = 10s */
{2, 2}, /* 18 = 15s */
{3, 2}, /* 19 = 20s */
{4, 2}, /* 20 = 25s */
{5, 2}, /* 21 = 30s */
{6, 2}, /* 22 = 35s */
{7, 2}, /* 23 = 40s */
{8, 2}, /* 24 = 45s */
{9, 2}, /* 25 = 50s */
{0xA, 2}, /* 26 = 55s */
{0xB, 2}, /* 27 = 60s */
{0xC, 2}, /* 28 = 65s */
{0xD, 2}, /* 29 = 70s */
{0xE, 2}, /* 30 = 75s */
{0xF, 2}, /* 31 = 80s */
{0, 3}, /* 32 = 50s */
{1, 3}, /* 33 = 100s */
{2, 3}, /* 34 = 150s */
{3, 3}, /* 35 = 200s */
{4, 3}, /* 36 = 250s */
{5, 3}, /* 37 = 300s */
{6, 3}, /* 38 = 350s */
{7, 3}, /* 39 = 400s */
{8, 3}, /* 40 = 450s */
{9, 3}, /* 41 = 500s */
{0xA, 3}, /* 42 = 550s */
{0xB, 3}, /* 43 = 600s */
{0xC, 3}, /* 44 = 650s */
{0xD, 3}, /* 45 = 700s */
{0xE, 3}, /* 46 = 750s */
{0xF, 3}, /* 47 = 800s */
{0, 4}, /* 48 = 100s */
{1, 4}, /* 49 = 200s */
{2, 4}, /* 50 = 300s */
{3, 4}, /* 51 = 400s */
{4, 4}, /* 52 = 500s */
{5, 4}, /* 53 = 600s */
{6, 4}, /* 54 = 700s */
{7, 4}, /* 55 = 800s */
{8, 4}, /* 56 = 900s */
{9, 4}, /* 57 = 1000s */
{0xA, 4}, /* 58 = 1100s */
{0xB, 4}, /* 59 = 1200s */
{0xC, 4}, /* 60 = 1300s */
{0xD, 4}, /* 61 = 1400s */
{0xE, 4}, /* 62 = 1500s */
{0xF, 4} /* 63 = 1600s */
};
#define SBC8360_ENABLE 0x120
#define SBC8360_BASETIME 0x121
static int timeout = 27;
static int wd_margin = 0xB;
static int wd_multiplier = 2;
static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout, "Index into timeout table (0-63) (default=27 (60s))");
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout,
"Watchdog cannot be stopped once started (default="
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
/*
* Kernel methods.
*/
/* Activate and pre-configure watchdog */
static void sbc8360_activate(void)
{
/* Enable the watchdog */
outb(0x0A, SBC8360_ENABLE);
msleep_interruptible(100);
outb(0x0B, SBC8360_ENABLE);
msleep_interruptible(100);
/* Set timeout multiplier */
outb(wd_multiplier, SBC8360_ENABLE);
msleep_interruptible(100);
/* Nothing happens until first sbc8360_ping() */
}
/* Kernel pings watchdog */
static void sbc8360_ping(void)
{
/* Write the base timer register */
outb(wd_margin, SBC8360_BASETIME);
}
/* stop watchdog */
static void sbc8360_stop(void)
{
/* De-activate the watchdog */
outb(0, SBC8360_ENABLE);
}
/* Userspace pings kernel driver, or requests clean close */
static ssize_t sbc8360_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
if (count) {
if (!nowayout) {
size_t i;
/* In case it was set long ago */
expect_close = 0;
for (i = 0; i != count; i++) {
char c;
if (get_user(c, buf + i))
return -EFAULT;
if (c == 'V')
expect_close = 42;
}
}
sbc8360_ping();
}
return count;
}
static int sbc8360_open(struct inode *inode, struct file *file)
{
if (test_and_set_bit(0, &sbc8360_is_open))
return -EBUSY;
if (nowayout)
__module_get(THIS_MODULE);
/* Activate and ping once to start the countdown */
sbc8360_activate();
sbc8360_ping();
return nonseekable_open(inode, file);
}
static int sbc8360_close(struct inode *inode, struct file *file)
{
if (expect_close == 42)
sbc8360_stop();
else
pr_crit("SBC8360 device closed unexpectedly. SBC8360 will not stop!\n");
clear_bit(0, &sbc8360_is_open);
expect_close = 0;
return 0;
}
/*
* Notifier for system down
*/
static int sbc8360_notify_sys(struct notifier_block *this, unsigned long code,
void *unused)
{
if (code == SYS_DOWN || code == SYS_HALT)
sbc8360_stop(); /* Disable the SBC8360 Watchdog */
return NOTIFY_DONE;
}
/*
* Kernel Interfaces
*/
static const struct file_operations sbc8360_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = sbc8360_write,
.open = sbc8360_open,
.release = sbc8360_close,
};
static struct miscdevice sbc8360_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &sbc8360_fops,
};
/*
* The SBC8360 needs to learn about soft shutdowns in order to
* turn the timebomb registers off.
*/
static struct notifier_block sbc8360_notifier = {
.notifier_call = sbc8360_notify_sys,
};
static int __init sbc8360_init(void)
{
int res;
unsigned long int mseconds = 60000;
if (timeout < 0 || timeout > 63) {
pr_err("Invalid timeout index (must be 0-63)\n");
res = -EINVAL;
goto out;
}
if (!request_region(SBC8360_ENABLE, 1, "SBC8360")) {
pr_err("ENABLE method I/O %X is not available\n",
SBC8360_ENABLE);
res = -EIO;
goto out;
}
if (!request_region(SBC8360_BASETIME, 1, "SBC8360")) {
pr_err("BASETIME method I/O %X is not available\n",
SBC8360_BASETIME);
res = -EIO;
goto out_nobasetimereg;
}
res = register_reboot_notifier(&sbc8360_notifier);
if (res) {
pr_err("Failed to register reboot notifier\n");
goto out_noreboot;
}
res = misc_register(&sbc8360_miscdev);
if (res) {
pr_err("failed to register misc device\n");
goto out_nomisc;
}
wd_margin = wd_times[timeout][0];
wd_multiplier = wd_times[timeout][1];
if (wd_multiplier == 1)
mseconds = (wd_margin + 1) * 500;
else if (wd_multiplier == 2)
mseconds = (wd_margin + 1) * 5000;
else if (wd_multiplier == 3)
mseconds = (wd_margin + 1) * 50000;
else if (wd_multiplier == 4)
mseconds = (wd_margin + 1) * 100000;
/* My kingdom for the ability to print "0.5 seconds" in the kernel! */
pr_info("Timeout set at %ld ms\n", mseconds);
return 0;
out_nomisc:
unregister_reboot_notifier(&sbc8360_notifier);
out_noreboot:
release_region(SBC8360_BASETIME, 1);
out_nobasetimereg:
release_region(SBC8360_ENABLE, 1);
out:
return res;
}
static void __exit sbc8360_exit(void)
{
misc_deregister(&sbc8360_miscdev);
unregister_reboot_notifier(&sbc8360_notifier);
release_region(SBC8360_ENABLE, 1);
release_region(SBC8360_BASETIME, 1);
}
module_init(sbc8360_init);
module_exit(sbc8360_exit);
MODULE_AUTHOR("Ian E. Morgan <imorgan@webcon.ca>");
MODULE_DESCRIPTION("SBC8360 watchdog driver");
MODULE_LICENSE("GPL");
MODULE_VERSION("1.01");
/* end of sbc8360.c */
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