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linux/drivers/watchdog/it87_wdt.c
Nat Gurumoorthy a134b82560 watchdog: Use "request_muxed_region" in it87 watchdog drivers 
Changes the it87 watchdog drivers to use "request_muxed_region".
Serialize access to the hardware by using "request_muxed_region" macro defined
by Alan Cox. Call to this macro will hold off the requestor if the resource is
currently busy. 

The use of the above macro makes it possible to get rid of
spinlocks in it8712f_wdt.c and it87_wdt.c watchdog drivers.
This also greatly simplifies the implementation of it87_wdt.c driver.

 "superio_enter" will return an error if call to "request_muxed_region" fails. 
Rest of the code change is to ripple an error return from superio_enter to
the top level.

Signed-off-by: Nat Gurumoorthy <natg@google.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2011-07-22 08:55:23 +00:00

781 lines
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/*
* Watchdog Timer Driver
* for ITE IT87xx Environment Control - Low Pin Count Input / Output
*
* (c) Copyright 2007 Oliver Schuster <olivers137@aol.com>
*
* Based on softdog.c by Alan Cox,
* 83977f_wdt.c by Jose Goncalves,
* it87.c by Chris Gauthron, Jean Delvare
*
* Data-sheets: Publicly available at the ITE website
* http://www.ite.com.tw/
*
* Support of the watchdog timers, which are available on
* IT8702, IT8712, IT8716, IT8718, IT8720, IT8721 and IT8726.
*
* 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.
*/
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/watchdog.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <asm/system.h>
#define WATCHDOG_VERSION "1.14"
#define WATCHDOG_NAME "IT87 WDT"
#define PFX WATCHDOG_NAME ": "
#define DRIVER_VERSION WATCHDOG_NAME " driver, v" WATCHDOG_VERSION "\n"
#define WD_MAGIC 'V'
/* Defaults for Module Parameter */
#define DEFAULT_NOGAMEPORT 0
#define DEFAULT_EXCLUSIVE 1
#define DEFAULT_TIMEOUT 60
#define DEFAULT_TESTMODE 0
#define DEFAULT_NOWAYOUT WATCHDOG_NOWAYOUT
/* IO Ports */
#define REG 0x2e
#define VAL 0x2f
/* Logical device Numbers LDN */
#define GPIO 0x07
#define GAMEPORT 0x09
#define CIR 0x0a
/* Configuration Registers and Functions */
#define LDNREG 0x07
#define CHIPID 0x20
#define CHIPREV 0x22
#define ACTREG 0x30
#define BASEREG 0x60
/* Chip Id numbers */
#define NO_DEV_ID 0xffff
#define IT8702_ID 0x8702
#define IT8705_ID 0x8705
#define IT8712_ID 0x8712
#define IT8716_ID 0x8716
#define IT8718_ID 0x8718
#define IT8720_ID 0x8720
#define IT8721_ID 0x8721
#define IT8726_ID 0x8726 /* the data sheet suggest wrongly 0x8716 */
/* GPIO Configuration Registers LDN=0x07 */
#define WDTCTRL 0x71
#define WDTCFG 0x72
#define WDTVALLSB 0x73
#define WDTVALMSB 0x74
/* GPIO Bits WDTCTRL */
#define WDT_CIRINT 0x80
#define WDT_MOUSEINT 0x40
#define WDT_KYBINT 0x20
#define WDT_GAMEPORT 0x10 /* not in it8718, it8720, it8721 */
#define WDT_FORCE 0x02
#define WDT_ZERO 0x01
/* GPIO Bits WDTCFG */
#define WDT_TOV1 0x80
#define WDT_KRST 0x40
#define WDT_TOVE 0x20
#define WDT_PWROK 0x10 /* not in it8721 */
#define WDT_INT_MASK 0x0f
/* CIR Configuration Register LDN=0x0a */
#define CIR_ILS 0x70
/* The default Base address is not always available, we use this */
#define CIR_BASE 0x0208
/* CIR Controller */
#define CIR_DR(b) (b)
#define CIR_IER(b) (b + 1)
#define CIR_RCR(b) (b + 2)
#define CIR_TCR1(b) (b + 3)
#define CIR_TCR2(b) (b + 4)
#define CIR_TSR(b) (b + 5)
#define CIR_RSR(b) (b + 6)
#define CIR_BDLR(b) (b + 5)
#define CIR_BDHR(b) (b + 6)
#define CIR_IIR(b) (b + 7)
/* Default Base address of Game port */
#define GP_BASE_DEFAULT 0x0201
/* wdt_status */
#define WDTS_TIMER_RUN 0
#define WDTS_DEV_OPEN 1
#define WDTS_KEEPALIVE 2
#define WDTS_LOCKED 3
#define WDTS_USE_GP 4
#define WDTS_EXPECTED 5
static unsigned int base, gpact, ciract, max_units, chip_type;
static unsigned long wdt_status;
static int nogameport = DEFAULT_NOGAMEPORT;
static int exclusive = DEFAULT_EXCLUSIVE;
static int timeout = DEFAULT_TIMEOUT;
static int testmode = DEFAULT_TESTMODE;
static int nowayout = DEFAULT_NOWAYOUT;
module_param(nogameport, int, 0);
MODULE_PARM_DESC(nogameport, "Forbid the activation of game port, default="
__MODULE_STRING(DEFAULT_NOGAMEPORT));
module_param(exclusive, int, 0);
MODULE_PARM_DESC(exclusive, "Watchdog exclusive device open, default="
__MODULE_STRING(DEFAULT_EXCLUSIVE));
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds, default="
__MODULE_STRING(DEFAULT_TIMEOUT));
module_param(testmode, int, 0);
MODULE_PARM_DESC(testmode, "Watchdog test mode (1 = no reboot), default="
__MODULE_STRING(DEFAULT_TESTMODE));
module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started, default="
__MODULE_STRING(WATCHDOG_NOWAYOUT));
/* Superio Chip */
static inline int superio_enter(void)
{
/*
* Try to reserve REG and REG + 1 for exclusive access.
*/
if (!request_muxed_region(REG, 2, WATCHDOG_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 superio_select(int ldn)
{
outb(LDNREG, REG);
outb(ldn, VAL);
}
static inline int superio_inb(int reg)
{
outb(reg, REG);
return inb(VAL);
}
static inline void superio_outb(int val, int reg)
{
outb(reg, REG);
outb(val, VAL);
}
static inline 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_outw(int val, int reg)
{
outb(reg++, REG);
outb(val >> 8, VAL);
outb(reg, REG);
outb(val, VAL);
}
/* Internal function, should be called after superio_select(GPIO) */
static void wdt_update_timeout(void)
{
unsigned char cfg = WDT_KRST;
int tm = timeout;
if (testmode)
cfg = 0;
if (tm <= max_units)
cfg |= WDT_TOV1;
else
tm /= 60;
if (chip_type != IT8721_ID)
cfg |= WDT_PWROK;
superio_outb(cfg, WDTCFG);
superio_outb(tm, WDTVALLSB);
if (max_units > 255)
superio_outb(tm>>8, WDTVALMSB);
}
static int wdt_round_time(int t)
{
t += 59;
t -= t % 60;
return t;
}
/* watchdog timer handling */
static void wdt_keepalive(void)
{
if (test_bit(WDTS_USE_GP, &wdt_status))
inb(base);
else
/* The timer reloads with around 5 msec delay */
outb(0x55, CIR_DR(base));
set_bit(WDTS_KEEPALIVE, &wdt_status);
}
static int wdt_start(void)
{
int ret = superio_enter();
if (ret)
return ret;
superio_select(GPIO);
if (test_bit(WDTS_USE_GP, &wdt_status))
superio_outb(WDT_GAMEPORT, WDTCTRL);
else
superio_outb(WDT_CIRINT, WDTCTRL);
wdt_update_timeout();
superio_exit();
return 0;
}
static int wdt_stop(void)
{
int ret = superio_enter();
if (ret)
return ret;
superio_select(GPIO);
superio_outb(0x00, WDTCTRL);
superio_outb(WDT_TOV1, WDTCFG);
superio_outb(0x00, WDTVALLSB);
if (max_units > 255)
superio_outb(0x00, WDTVALMSB);
superio_exit();
return 0;
}
/**
* wdt_set_timeout - set a new timeout value with watchdog ioctl
* @t: timeout value in seconds
*
* The hardware device has a 8 or 16 bit watchdog timer (depends on
* chip version) that can be configured to count seconds or minutes.
*
* Used within WDIOC_SETTIMEOUT watchdog device ioctl.
*/
static int wdt_set_timeout(int t)
{
if (t < 1 || t > max_units * 60)
return -EINVAL;
if (t > max_units)
timeout = wdt_round_time(t);
else
timeout = t;
if (test_bit(WDTS_TIMER_RUN, &wdt_status)) {
int ret = superio_enter();
if (ret)
return ret;
superio_select(GPIO);
wdt_update_timeout();
superio_exit();
}
return 0;
}
/**
* wdt_get_status - determines the status supported by watchdog ioctl
* @status: status returned to user space
*
* The status bit of the device does not allow to distinguish
* between a regular system reset and a watchdog forced reset.
* But, in test mode it is useful, so it is supported through
* WDIOC_GETSTATUS watchdog ioctl. Additionally the driver
* reports the keepalive signal and the acception of the magic.
*
* Used within WDIOC_GETSTATUS watchdog device ioctl.
*/
static int wdt_get_status(int *status)
{
*status = 0;
if (testmode) {
int ret = superio_enter();
if (ret)
return ret;
superio_select(GPIO);
if (superio_inb(WDTCTRL) & WDT_ZERO) {
superio_outb(0x00, WDTCTRL);
clear_bit(WDTS_TIMER_RUN, &wdt_status);
*status |= WDIOF_CARDRESET;
}
superio_exit();
}
if (test_and_clear_bit(WDTS_KEEPALIVE, &wdt_status))
*status |= WDIOF_KEEPALIVEPING;
if (test_bit(WDTS_EXPECTED, &wdt_status))
*status |= WDIOF_MAGICCLOSE;
return 0;
}
/* /dev/watchdog handling */
/**
* wdt_open - watchdog file_operations .open
* @inode: inode of the device
* @file: file handle to the device
*
* The watchdog timer starts by opening the device.
*
* Used within the file operation of the watchdog device.
*/
static int wdt_open(struct inode *inode, struct file *file)
{
if (exclusive && test_and_set_bit(WDTS_DEV_OPEN, &wdt_status))
return -EBUSY;
if (!test_and_set_bit(WDTS_TIMER_RUN, &wdt_status)) {
int ret;
if (nowayout && !test_and_set_bit(WDTS_LOCKED, &wdt_status))
__module_get(THIS_MODULE);
ret = wdt_start();
if (ret) {
clear_bit(WDTS_LOCKED, &wdt_status);
clear_bit(WDTS_TIMER_RUN, &wdt_status);
clear_bit(WDTS_DEV_OPEN, &wdt_status);
return ret;
}
}
return nonseekable_open(inode, file);
}
/**
* wdt_release - watchdog file_operations .release
* @inode: inode of the device
* @file: file handle to the device
*
* Closing the watchdog device either stops the watchdog timer
* or in the case, that nowayout is set or the magic character
* wasn't written, a critical warning about an running watchdog
* timer is given.
*
* Used within the file operation of the watchdog device.
*/
static int wdt_release(struct inode *inode, struct file *file)
{
if (test_bit(WDTS_TIMER_RUN, &wdt_status)) {
if (test_and_clear_bit(WDTS_EXPECTED, &wdt_status)) {
int ret = wdt_stop();
if (ret) {
/*
* Stop failed. Just keep the watchdog alive
* and hope nothing bad happens.
*/
set_bit(WDTS_EXPECTED, &wdt_status);
wdt_keepalive();
return ret;
}
clear_bit(WDTS_TIMER_RUN, &wdt_status);
} else {
wdt_keepalive();
printk(KERN_CRIT PFX
"unexpected close, not stopping watchdog!\n");
}
}
clear_bit(WDTS_DEV_OPEN, &wdt_status);
return 0;
}
/**
* wdt_write - watchdog file_operations .write
* @file: file handle to the watchdog
* @buf: buffer to write
* @count: count of bytes
* @ppos: pointer to the position to write. No seeks allowed
*
* A write to a watchdog device is defined as a keepalive signal. Any
* write of data will do, as we don't define content meaning.
*
* Used within the file operation of the watchdog device.
*/
static ssize_t wdt_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
if (count) {
clear_bit(WDTS_EXPECTED, &wdt_status);
wdt_keepalive();
}
if (!nowayout) {
size_t ofs;
/* note: just in case someone wrote the magic character long ago */
for (ofs = 0; ofs != count; ofs++) {
char c;
if (get_user(c, buf + ofs))
return -EFAULT;
if (c == WD_MAGIC)
set_bit(WDTS_EXPECTED, &wdt_status);
}
}
return count;
}
static const struct watchdog_info ident = {
.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
.firmware_version = 1,
.identity = WATCHDOG_NAME,
};
/**
* wdt_ioctl - watchdog file_operations .unlocked_ioctl
* @file: file handle to the device
* @cmd: watchdog command
* @arg: argument pointer
*
* The watchdog API defines a common set of functions for all watchdogs
* according to their available features.
*
* Used within the file operation of the watchdog device.
*/
static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
int rc = 0, status, new_options, new_timeout;
union {
struct watchdog_info __user *ident;
int __user *i;
} uarg;
uarg.i = (int __user *)arg;
switch (cmd) {
case WDIOC_GETSUPPORT:
return copy_to_user(uarg.ident,
&ident, sizeof(ident)) ? -EFAULT : 0;
case WDIOC_GETSTATUS:
rc = wdt_get_status(&status);
if (rc)
return rc;
return put_user(status, uarg.i);
case WDIOC_GETBOOTSTATUS:
return put_user(0, uarg.i);
case WDIOC_KEEPALIVE:
wdt_keepalive();
return 0;
case WDIOC_SETOPTIONS:
if (get_user(new_options, uarg.i))
return -EFAULT;
switch (new_options) {
case WDIOS_DISABLECARD:
if (test_bit(WDTS_TIMER_RUN, &wdt_status)) {
rc = wdt_stop();
if (rc)
return rc;
}
clear_bit(WDTS_TIMER_RUN, &wdt_status);
return 0;
case WDIOS_ENABLECARD:
if (!test_and_set_bit(WDTS_TIMER_RUN, &wdt_status)) {
rc = wdt_start();
if (rc) {
clear_bit(WDTS_TIMER_RUN, &wdt_status);
return rc;
}
}
return 0;
default:
return -EFAULT;
}
case WDIOC_SETTIMEOUT:
if (get_user(new_timeout, uarg.i))
return -EFAULT;
rc = wdt_set_timeout(new_timeout);
case WDIOC_GETTIMEOUT:
if (put_user(timeout, uarg.i))
return -EFAULT;
return rc;
default:
return -ENOTTY;
}
}
static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
void *unused)
{
if (code == SYS_DOWN || code == SYS_HALT)
wdt_stop();
return NOTIFY_DONE;
}
static const struct file_operations wdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = wdt_write,
.unlocked_ioctl = wdt_ioctl,
.open = wdt_open,
.release = wdt_release,
};
static struct miscdevice wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &wdt_fops,
};
static struct notifier_block wdt_notifier = {
.notifier_call = wdt_notify_sys,
};
static int __init it87_wdt_init(void)
{
int rc = 0;
int try_gameport = !nogameport;
u8 chip_rev;
int gp_rreq_fail = 0;
wdt_status = 0;
rc = superio_enter();
if (rc)
return rc;
chip_type = superio_inw(CHIPID);
chip_rev = superio_inb(CHIPREV) & 0x0f;
superio_exit();
switch (chip_type) {
case IT8702_ID:
max_units = 255;
break;
case IT8712_ID:
max_units = (chip_rev < 8) ? 255 : 65535;
break;
case IT8716_ID:
case IT8726_ID:
max_units = 65535;
break;
case IT8718_ID:
case IT8720_ID:
case IT8721_ID:
max_units = 65535;
try_gameport = 0;
break;
case IT8705_ID:
printk(KERN_ERR PFX
"Unsupported Chip found, Chip %04x Revision %02x\n",
chip_type, chip_rev);
return -ENODEV;
case NO_DEV_ID:
printk(KERN_ERR PFX "no device\n");
return -ENODEV;
default:
printk(KERN_ERR PFX
"Unknown Chip found, Chip %04x Revision %04x\n",
chip_type, chip_rev);
return -ENODEV;
}
rc = superio_enter();
if (rc)
return rc;
superio_select(GPIO);
superio_outb(WDT_TOV1, WDTCFG);
superio_outb(0x00, WDTCTRL);
/* First try to get Gameport support */
if (try_gameport) {
superio_select(GAMEPORT);
base = superio_inw(BASEREG);
if (!base) {
base = GP_BASE_DEFAULT;
superio_outw(base, BASEREG);
}
gpact = superio_inb(ACTREG);
superio_outb(0x01, ACTREG);
if (request_region(base, 1, WATCHDOG_NAME))
set_bit(WDTS_USE_GP, &wdt_status);
else
gp_rreq_fail = 1;
}
/* If we haven't Gameport support, try to get CIR support */
if (!test_bit(WDTS_USE_GP, &wdt_status)) {
if (!request_region(CIR_BASE, 8, WATCHDOG_NAME)) {
if (gp_rreq_fail)
printk(KERN_ERR PFX
"I/O Address 0x%04x and 0x%04x"
" already in use\n", base, CIR_BASE);
else
printk(KERN_ERR PFX
"I/O Address 0x%04x already in use\n",
CIR_BASE);
rc = -EIO;
goto err_out;
}
base = CIR_BASE;
superio_select(CIR);
superio_outw(base, BASEREG);
superio_outb(0x00, CIR_ILS);
ciract = superio_inb(ACTREG);
superio_outb(0x01, ACTREG);
if (gp_rreq_fail) {
superio_select(GAMEPORT);
superio_outb(gpact, ACTREG);
}
}
if (timeout < 1 || timeout > max_units * 60) {
timeout = DEFAULT_TIMEOUT;
printk(KERN_WARNING PFX
"Timeout value out of range, use default %d sec\n",
DEFAULT_TIMEOUT);
}
if (timeout > max_units)
timeout = wdt_round_time(timeout);
rc = register_reboot_notifier(&wdt_notifier);
if (rc) {
printk(KERN_ERR PFX
"Cannot register reboot notifier (err=%d)\n", rc);
goto err_out_region;
}
rc = misc_register(&wdt_miscdev);
if (rc) {
printk(KERN_ERR PFX
"Cannot register miscdev on minor=%d (err=%d)\n",
wdt_miscdev.minor, rc);
goto err_out_reboot;
}
/* Initialize CIR to use it as keepalive source */
if (!test_bit(WDTS_USE_GP, &wdt_status)) {
outb(0x00, CIR_RCR(base));
outb(0xc0, CIR_TCR1(base));
outb(0x5c, CIR_TCR2(base));
outb(0x10, CIR_IER(base));
outb(0x00, CIR_BDHR(base));
outb(0x01, CIR_BDLR(base));
outb(0x09, CIR_IER(base));
}
printk(KERN_INFO PFX "Chip IT%04x revision %d initialized. "
"timeout=%d sec (nowayout=%d testmode=%d exclusive=%d "
"nogameport=%d)\n", chip_type, chip_rev, timeout,
nowayout, testmode, exclusive, nogameport);
superio_exit();
return 0;
err_out_reboot:
unregister_reboot_notifier(&wdt_notifier);
err_out_region:
release_region(base, test_bit(WDTS_USE_GP, &wdt_status) ? 1 : 8);
if (!test_bit(WDTS_USE_GP, &wdt_status)) {
superio_select(CIR);
superio_outb(ciract, ACTREG);
}
err_out:
if (try_gameport) {
superio_select(GAMEPORT);
superio_outb(gpact, ACTREG);
}
superio_exit();
return rc;
}
static void __exit it87_wdt_exit(void)
{
if (superio_enter() == 0) {
superio_select(GPIO);
superio_outb(0x00, WDTCTRL);
superio_outb(0x00, WDTCFG);
superio_outb(0x00, WDTVALLSB);
if (max_units > 255)
superio_outb(0x00, WDTVALMSB);
if (test_bit(WDTS_USE_GP, &wdt_status)) {
superio_select(GAMEPORT);
superio_outb(gpact, ACTREG);
} else {
superio_select(CIR);
superio_outb(ciract, ACTREG);
}
superio_exit();
}
misc_deregister(&wdt_miscdev);
unregister_reboot_notifier(&wdt_notifier);
release_region(base, test_bit(WDTS_USE_GP, &wdt_status) ? 1 : 8);
}
module_init(it87_wdt_init);
module_exit(it87_wdt_exit);
MODULE_AUTHOR("Oliver Schuster");
MODULE_DESCRIPTION("Hardware Watchdog Device Driver for IT87xx EC-LPC I/O");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
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