linux-stable/drivers/watchdog/it8712f_wdt.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

454 lines
10 KiB
C

/*
* IT8712F "Smart Guardian" Watchdog support
*
* Copyright (c) 2006-2007 Jorge Boncompte - DTI2 <jorge@dti2.net>
*
* Based on info and code taken from:
*
* drivers/char/watchdog/scx200_wdt.c
* drivers/hwmon/it87.c
* IT8712F EC-LPC I/O Preliminary Specification 0.8.2
* IT8712F EC-LPC I/O Preliminary Specification 0.9.3
*
* 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.
*
* The author(s) of this software shall not be held liable for damages
* of any nature resulting due to the use of this software. This
* software is provided AS-IS with no warranties.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/init.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/fs.h>
#include <linux/spinlock.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/ioport.h>
#define DEBUG
#define NAME "it8712f_wdt"
MODULE_AUTHOR("Jorge Boncompte - DTI2 <jorge@dti2.net>");
MODULE_DESCRIPTION("IT8712F Watchdog Driver");
MODULE_LICENSE("GPL");
static int max_units = 255;
static int margin = 60; /* in seconds */
module_param(margin, int, 0);
MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
static unsigned long wdt_open;
static unsigned expect_close;
static unsigned char revision;
/* Dog Food address - We use the game port address */
static unsigned short address;
#define REG 0x2e /* The register to read/write */
#define VAL 0x2f /* The value to read/write */
#define LDN 0x07 /* Register: Logical device select */
#define DEVID 0x20 /* Register: Device ID */
#define DEVREV 0x22 /* Register: Device Revision */
#define ACT_REG 0x30 /* LDN Register: Activation */
#define BASE_REG 0x60 /* LDN Register: Base address */
#define IT8712F_DEVID 0x8712
#define LDN_GPIO 0x07 /* GPIO and Watch Dog Timer */
#define LDN_GAME 0x09 /* Game Port */
#define WDT_CONTROL 0x71 /* WDT Register: Control */
#define WDT_CONFIG 0x72 /* WDT Register: Configuration */
#define WDT_TIMEOUT 0x73 /* WDT Register: Timeout Value */
#define WDT_RESET_GAME 0x10 /* Reset timer on read or write to game port */
#define WDT_RESET_KBD 0x20 /* Reset timer on keyboard interrupt */
#define WDT_RESET_MOUSE 0x40 /* Reset timer on mouse interrupt */
#define WDT_RESET_CIR 0x80 /* Reset timer on consumer IR interrupt */
#define WDT_UNIT_SEC 0x80 /* If 0 in MINUTES */
#define WDT_OUT_PWROK 0x10 /* Pulse PWROK on timeout */
#define WDT_OUT_KRST 0x40 /* Pulse reset on timeout */
static int wdt_control_reg = WDT_RESET_GAME;
module_param(wdt_control_reg, int, 0);
MODULE_PARM_DESC(wdt_control_reg, "Value to write to watchdog control "
"register. The default WDT_RESET_GAME resets the timer on "
"game port reads that this driver generates. You can also "
"use KBD, MOUSE or CIR if you have some external way to "
"generate those interrupts.");
static int superio_inb(int reg)
{
outb(reg, REG);
return inb(VAL);
}
static void superio_outb(int val, int reg)
{
outb(reg, REG);
outb(val, VAL);
}
static int superio_inw(int reg)
{
int val;
outb(reg++, REG);
val = inb(VAL) << 8;
outb(reg, REG);
val |= inb(VAL);
return val;
}
static inline void superio_select(int ldn)
{
outb(LDN, REG);
outb(ldn, VAL);
}
static inline int superio_enter(void)
{
/*
* Try to reserve REG and REG + 1 for exclusive access.
*/
if (!request_muxed_region(REG, 2, NAME))
return -EBUSY;
outb(0x87, REG);
outb(0x01, REG);
outb(0x55, REG);
outb(0x55, REG);
return 0;
}
static inline void superio_exit(void)
{
outb(0x02, REG);
outb(0x02, VAL);
release_region(REG, 2);
}
static inline void it8712f_wdt_ping(void)
{
if (wdt_control_reg & WDT_RESET_GAME)
inb(address);
}
static void it8712f_wdt_update_margin(void)
{
int config = WDT_OUT_KRST | WDT_OUT_PWROK;
int units = margin;
/* Switch to minutes precision if the configured margin
* value does not fit within the register width.
*/
if (units <= max_units) {
config |= WDT_UNIT_SEC; /* else UNIT is MINUTES */
pr_info("timer margin %d seconds\n", units);
} else {
units /= 60;
pr_info("timer margin %d minutes\n", units);
}
superio_outb(config, WDT_CONFIG);
if (revision >= 0x08)
superio_outb(units >> 8, WDT_TIMEOUT + 1);
superio_outb(units, WDT_TIMEOUT);
}
static int it8712f_wdt_get_status(void)
{
if (superio_inb(WDT_CONTROL) & 0x01)
return WDIOF_CARDRESET;
else
return 0;
}
static int it8712f_wdt_enable(void)
{
int ret = superio_enter();
if (ret)
return ret;
pr_debug("enabling watchdog timer\n");
superio_select(LDN_GPIO);
superio_outb(wdt_control_reg, WDT_CONTROL);
it8712f_wdt_update_margin();
superio_exit();
it8712f_wdt_ping();
return 0;
}
static int it8712f_wdt_disable(void)
{
int ret = superio_enter();
if (ret)
return ret;
pr_debug("disabling watchdog timer\n");
superio_select(LDN_GPIO);
superio_outb(0, WDT_CONFIG);
superio_outb(0, WDT_CONTROL);
if (revision >= 0x08)
superio_outb(0, WDT_TIMEOUT + 1);
superio_outb(0, WDT_TIMEOUT);
superio_exit();
return 0;
}
static int it8712f_wdt_notify(struct notifier_block *this,
unsigned long code, void *unused)
{
if (code == SYS_HALT || code == SYS_POWER_OFF)
if (!nowayout)
it8712f_wdt_disable();
return NOTIFY_DONE;
}
static struct notifier_block it8712f_wdt_notifier = {
.notifier_call = it8712f_wdt_notify,
};
static ssize_t it8712f_wdt_write(struct file *file, const char __user *data,
size_t len, loff_t *ppos)
{
/* check for a magic close character */
if (len) {
size_t i;
it8712f_wdt_ping();
expect_close = 0;
for (i = 0; i < len; ++i) {
char c;
if (get_user(c, data + i))
return -EFAULT;
if (c == 'V')
expect_close = 42;
}
}
return len;
}
static long it8712f_wdt_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
void __user *argp = (void __user *)arg;
int __user *p = argp;
static const struct watchdog_info ident = {
.identity = "IT8712F Watchdog",
.firmware_version = 1,
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
WDIOF_MAGICCLOSE,
};
int value;
int ret;
switch (cmd) {
case WDIOC_GETSUPPORT:
if (copy_to_user(argp, &ident, sizeof(ident)))
return -EFAULT;
return 0;
case WDIOC_GETSTATUS:
ret = superio_enter();
if (ret)
return ret;
superio_select(LDN_GPIO);
value = it8712f_wdt_get_status();
superio_exit();
return put_user(value, p);
case WDIOC_GETBOOTSTATUS:
return put_user(0, p);
case WDIOC_KEEPALIVE:
it8712f_wdt_ping();
return 0;
case WDIOC_SETTIMEOUT:
if (get_user(value, p))
return -EFAULT;
if (value < 1)
return -EINVAL;
if (value > (max_units * 60))
return -EINVAL;
margin = value;
ret = superio_enter();
if (ret)
return ret;
superio_select(LDN_GPIO);
it8712f_wdt_update_margin();
superio_exit();
it8712f_wdt_ping();
/* Fall through */
case WDIOC_GETTIMEOUT:
if (put_user(margin, p))
return -EFAULT;
return 0;
default:
return -ENOTTY;
}
}
static int it8712f_wdt_open(struct inode *inode, struct file *file)
{
int ret;
/* only allow one at a time */
if (test_and_set_bit(0, &wdt_open))
return -EBUSY;
ret = it8712f_wdt_enable();
if (ret)
return ret;
return nonseekable_open(inode, file);
}
static int it8712f_wdt_release(struct inode *inode, struct file *file)
{
if (expect_close != 42) {
pr_warn("watchdog device closed unexpectedly, will not disable the watchdog timer\n");
} else if (!nowayout) {
if (it8712f_wdt_disable())
pr_warn("Watchdog disable failed\n");
}
expect_close = 0;
clear_bit(0, &wdt_open);
return 0;
}
static const struct file_operations it8712f_wdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = it8712f_wdt_write,
.unlocked_ioctl = it8712f_wdt_ioctl,
.open = it8712f_wdt_open,
.release = it8712f_wdt_release,
};
static struct miscdevice it8712f_wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &it8712f_wdt_fops,
};
static int __init it8712f_wdt_find(unsigned short *address)
{
int err = -ENODEV;
int chip_type;
int ret = superio_enter();
if (ret)
return ret;
chip_type = superio_inw(DEVID);
if (chip_type != IT8712F_DEVID)
goto exit;
superio_select(LDN_GAME);
superio_outb(1, ACT_REG);
if (!(superio_inb(ACT_REG) & 0x01)) {
pr_err("Device not activated, skipping\n");
goto exit;
}
*address = superio_inw(BASE_REG);
if (*address == 0) {
pr_err("Base address not set, skipping\n");
goto exit;
}
err = 0;
revision = superio_inb(DEVREV) & 0x0f;
/* Later revisions have 16-bit values per datasheet 0.9.1 */
if (revision >= 0x08)
max_units = 65535;
if (margin > (max_units * 60))
margin = (max_units * 60);
pr_info("Found IT%04xF chip revision %d - using DogFood address 0x%x\n",
chip_type, revision, *address);
exit:
superio_exit();
return err;
}
static int __init it8712f_wdt_init(void)
{
int err = 0;
if (it8712f_wdt_find(&address))
return -ENODEV;
if (!request_region(address, 1, "IT8712F Watchdog")) {
pr_warn("watchdog I/O region busy\n");
return -EBUSY;
}
err = it8712f_wdt_disable();
if (err) {
pr_err("unable to disable watchdog timer\n");
goto out;
}
err = register_reboot_notifier(&it8712f_wdt_notifier);
if (err) {
pr_err("unable to register reboot notifier\n");
goto out;
}
err = misc_register(&it8712f_wdt_miscdev);
if (err) {
pr_err("cannot register miscdev on minor=%d (err=%d)\n",
WATCHDOG_MINOR, err);
goto reboot_out;
}
return 0;
reboot_out:
unregister_reboot_notifier(&it8712f_wdt_notifier);
out:
release_region(address, 1);
return err;
}
static void __exit it8712f_wdt_exit(void)
{
misc_deregister(&it8712f_wdt_miscdev);
unregister_reboot_notifier(&it8712f_wdt_notifier);
release_region(address, 1);
}
module_init(it8712f_wdt_init);
module_exit(it8712f_wdt_exit);