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sc1200 watchdog driver: Fix locking, sems and coding style

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Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Alan Cox
2008-08-04 17:56:28 +01:00
committed by Linus Torvalds
parent 81830061bb
commit 103a1d5c57
1 changed files with 113 additions and 92 deletions
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119
drivers/watchdog/sc1200wdt.c
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@@ -15,14 +15,18 @@
* *
* Changelog: * Changelog:
* 20020220 Zwane Mwaikambo Code based on datasheet, no hardware. * 20020220 Zwane Mwaikambo Code based on datasheet, no hardware.
* 20020221 Zwane Mwaikambo Cleanups as suggested by Jeff Garzik and Alan Cox. * 20020221 Zwane Mwaikambo Cleanups as suggested by Jeff Garzik
* and Alan Cox.
* 20020222 Zwane Mwaikambo Added probing. * 20020222 Zwane Mwaikambo Added probing.
* 20020225 Zwane Mwaikambo Added ISAPNP support. * 20020225 Zwane Mwaikambo Added ISAPNP support.
* 20020412 Rob Radez Broke out start/stop functions * 20020412 Rob Radez Broke out start/stop functions
* <rob@osinvestor.com> Return proper status instead of temperature warning * <rob@osinvestor.com> Return proper status instead of
* Add WDIOC_GETBOOTSTATUS and WDIOC_SETOPTIONS ioctls * temperature warning
* Add WDIOC_GETBOOTSTATUS and
* WDIOC_SETOPTIONS ioctls
* Fix CONFIG_WATCHDOG_NOWAYOUT * Fix CONFIG_WATCHDOG_NOWAYOUT
* 20020530 Joel Becker Add Matt Domsch's nowayout module option * 20020530 Joel Becker Add Matt Domsch's nowayout module
* option
* 20030116 Adam Belay Updated to the latest pnp code * 20030116 Adam Belay Updated to the latest pnp code
* *
*/ */
@@ -39,9 +43,8 @@
#include <linux/pnp.h> #include <linux/pnp.h>
#include <linux/fs.h> #include <linux/fs.h>
#include <linux/semaphore.h> #include <linux/semaphore.h>
#include <linux/io.h>
#include <asm/io.h> #include <linux/uaccess.h>
#include <asm/uaccess.h>
#define SC1200_MODULE_VER "build 20020303" #define SC1200_MODULE_VER "build 20020303"
#define SC1200_MODULE_NAME "sc1200wdt" #define SC1200_MODULE_NAME "sc1200wdt"
@@ -72,7 +75,7 @@ static char banner[] __initdata = KERN_INFO PFX SC1200_MODULE_VER;
static int timeout = 1; static int timeout = 1;
static int io = -1; static int io = -1;
static int io_len = 2; /* for non plug and play */ static int io_len = 2; /* for non plug and play */
static struct semaphore open_sem; static unsigned long open_flag;
static char expect_close; static char expect_close;
static DEFINE_SPINLOCK(sc1200wdt_lock); /* io port access serialisation */ static DEFINE_SPINLOCK(sc1200wdt_lock); /* io port access serialisation */
@@ -81,7 +84,8 @@ static int isapnp = 1;
static struct pnp_dev *wdt_dev; static struct pnp_dev *wdt_dev;
module_param(isapnp, int, 0); module_param(isapnp, int, 0);
MODULE_PARM_DESC(isapnp, "When set to 0 driver ISA PnP support will be disabled"); MODULE_PARM_DESC(isapnp,
"When set to 0 driver ISA PnP support will be disabled");
#endif #endif
module_param(io, int, 0); module_param(io, int, 0);
@@ -91,26 +95,40 @@ MODULE_PARM_DESC(timeout, "range is 0-255 minutes, default is 1");
static int nowayout = WATCHDOG_NOWAYOUT; static int nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, int, 0); module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); MODULE_PARM_DESC(nowayout,
"Watchdog cannot be stopped once started (default="
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
/* Read from Data Register */ /* Read from Data Register */
static inline void sc1200wdt_read_data(unsigned char index, unsigned char *data) static inline void __sc1200wdt_read_data(unsigned char index,
unsigned char *data)
{ {
spin_lock(&sc1200wdt_lock);
outb_p(index, PMIR); outb_p(index, PMIR);
*data = inb(PMDR); *data = inb(PMDR);
}
static void sc1200wdt_read_data(unsigned char index, unsigned char *data)
{
spin_lock(&sc1200wdt_lock);
__sc1200wdt_read_data(index, data);
spin_unlock(&sc1200wdt_lock); spin_unlock(&sc1200wdt_lock);
} }
/* Write to Data Register */ /* Write to Data Register */
static inline void sc1200wdt_write_data(unsigned char index, unsigned char data) static inline void __sc1200wdt_write_data(unsigned char index,
unsigned char data)
{ {
spin_lock(&sc1200wdt_lock);
outb_p(index, PMIR); outb_p(index, PMIR);
outb(data, PMDR); outb(data, PMDR);
}
static inline void sc1200wdt_write_data(unsigned char index,
unsigned char data)
{
spin_lock(&sc1200wdt_lock);
__sc1200wdt_write_data(index, data);
spin_unlock(&sc1200wdt_lock); spin_unlock(&sc1200wdt_lock);
} }
@@ -118,22 +136,23 @@ static inline void sc1200wdt_write_data(unsigned char index, unsigned char data)
static void sc1200wdt_start(void) static void sc1200wdt_start(void)
{ {
unsigned char reg; unsigned char reg;
spin_lock(&sc1200wdt_lock);
sc1200wdt_read_data(WDCF, &reg); __sc1200wdt_read_data(WDCF, &reg);
/* assert WDO when any of the following interrupts are triggered too */ /* assert WDO when any of the following interrupts are triggered too */
reg |= (KBC_IRQ | MSE_IRQ | UART1_IRQ | UART2_IRQ); reg |= (KBC_IRQ | MSE_IRQ | UART1_IRQ | UART2_IRQ);
sc1200wdt_write_data(WDCF, reg); __sc1200wdt_write_data(WDCF, reg);
/* set the timeout and get the ball rolling */ /* set the timeout and get the ball rolling */
sc1200wdt_write_data(WDTO, timeout); __sc1200wdt_write_data(WDTO, timeout);
}
spin_unlock(&sc1200wdt_lock);
}
static void sc1200wdt_stop(void) static void sc1200wdt_stop(void)
{ {
sc1200wdt_write_data(WDTO, 0); sc1200wdt_write_data(WDTO, 0);
} }
/* This returns the status of the WDO signal, inactive high. */ /* This returns the status of the WDO signal, inactive high. */
static inline int sc1200wdt_status(void) static inline int sc1200wdt_status(void)
{ {
@@ -144,14 +163,13 @@ static inline int sc1200wdt_status(void)
* KEEPALIVEPING which is a bit of a kludge because there's nothing * KEEPALIVEPING which is a bit of a kludge because there's nothing
* else for enabled/disabled status * else for enabled/disabled status
*/ */
return (ret & 0x01) ? 0 : WDIOF_KEEPALIVEPING; /* bits 1 - 7 are undefined */ return (ret & 0x01) ? 0 : WDIOF_KEEPALIVEPING;
} }
static int sc1200wdt_open(struct inode *inode, struct file *file) static int sc1200wdt_open(struct inode *inode, struct file *file)
{ {
/* allow one at a time */ /* allow one at a time */
if (down_trylock(&open_sem)) if (test_and_set_bit(0, &open_flag))
return -EBUSY; return -EBUSY;
if (timeout > MAX_TIMEOUT) if (timeout > MAX_TIMEOUT)
@@ -164,20 +182,20 @@ static int sc1200wdt_open(struct inode *inode, struct file *file)
} }
static int sc1200wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg) static long sc1200wdt_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{ {
int new_timeout; int new_timeout;
void __user *argp = (void __user *)arg; void __user *argp = (void __user *)arg;
int __user *p = argp; int __user *p = argp;
static struct watchdog_info ident = { static const struct watchdog_info ident = {
.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE, .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
WDIOF_MAGICCLOSE,
.firmware_version = 0, .firmware_version = 0,
.identity = "PC87307/PC97307", .identity = "PC87307/PC97307",
}; };
switch (cmd) { switch (cmd) {
default:
return -ENOTTY;
case WDIOC_GETSUPPORT: case WDIOC_GETSUPPORT:
if (copy_to_user(argp, &ident, sizeof ident)) if (copy_to_user(argp, &ident, sizeof ident))
@@ -197,12 +215,10 @@ static int sc1200wdt_ioctl(struct inode *inode, struct file *file, unsigned int
case WDIOC_SETTIMEOUT: case WDIOC_SETTIMEOUT:
if (get_user(new_timeout, p)) if (get_user(new_timeout, p))
return -EFAULT; return -EFAULT;
/* the API states this is given in secs */ /* the API states this is given in secs */
new_timeout /= 60; new_timeout /= 60;
if (new_timeout < 0 || new_timeout > MAX_TIMEOUT) if (new_timeout < 0 || new_timeout > MAX_TIMEOUT)
return -EINVAL; return -EINVAL;
timeout = new_timeout; timeout = new_timeout;
sc1200wdt_write_data(WDTO, timeout); sc1200wdt_write_data(WDTO, timeout);
/* fall through and return the new timeout */ /* fall through and return the new timeout */
@@ -229,6 +245,8 @@ static int sc1200wdt_ioctl(struct inode *inode, struct file *file, unsigned int
return retval; return retval;
} }
default:
return -ENOTTY;
} }
} }
@@ -240,16 +258,18 @@ static int sc1200wdt_release(struct inode *inode, struct file *file)
printk(KERN_INFO PFX "Watchdog disabled\n"); printk(KERN_INFO PFX "Watchdog disabled\n");
} else { } else {
sc1200wdt_write_data(WDTO, timeout); sc1200wdt_write_data(WDTO, timeout);
printk(KERN_CRIT PFX "Unexpected close!, timeout = %d min(s)\n", timeout); printk(KERN_CRIT PFX
"Unexpected close!, timeout = %d min(s)\n", timeout);
} }
up(&open_sem); clear_bit(0, &open_flag);
expect_close = 0; expect_close = 0;
return 0; return 0;
} }
static ssize_t sc1200wdt_write(struct file *file, const char __user *data, size_t len, loff_t *ppos) static ssize_t sc1200wdt_write(struct file *file, const char __user *data,
size_t len, loff_t *ppos)
{ {
if (len) { if (len) {
if (!nowayout) { if (!nowayout) {
@@ -275,7 +295,8 @@ static ssize_t sc1200wdt_write(struct file *file, const char __user *data, size_
} }
static int sc1200wdt_notify_sys(struct notifier_block *this, unsigned long code, void *unused) static int sc1200wdt_notify_sys(struct notifier_block *this,
unsigned long code, void *unused)
{ {
if (code == SYS_DOWN || code == SYS_HALT) if (code == SYS_DOWN || code == SYS_HALT)
sc1200wdt_stop(); sc1200wdt_stop();
@@ -284,23 +305,20 @@ static int sc1200wdt_notify_sys(struct notifier_block *this, unsigned long code,
} }
static struct notifier_block sc1200wdt_notifier = static struct notifier_block sc1200wdt_notifier = {
{
.notifier_call = sc1200wdt_notify_sys, .notifier_call = sc1200wdt_notify_sys,
}; };
static const struct file_operations sc1200wdt_fops = static const struct file_operations sc1200wdt_fops = {
{
.owner = THIS_MODULE, .owner = THIS_MODULE,
.llseek = no_llseek, .llseek = no_llseek,
.write = sc1200wdt_write, .write = sc1200wdt_write,
.ioctl = sc1200wdt_ioctl, .unlocked_ioctl = sc1200wdt_ioctl,
.open = sc1200wdt_open, .open = sc1200wdt_open,
.release = sc1200wdt_release, .release = sc1200wdt_release,
}; };
static struct miscdevice sc1200wdt_miscdev = static struct miscdevice sc1200wdt_miscdev = {
{
.minor = WATCHDOG_MINOR, .minor = WATCHDOG_MINOR,
.name = "watchdog", .name = "watchdog",
.fops = &sc1200wdt_fops, .fops = &sc1200wdt_fops,
@@ -312,8 +330,8 @@ static int __init sc1200wdt_probe(void)
/* The probe works by reading the PMC3 register's default value of 0x0e /* The probe works by reading the PMC3 register's default value of 0x0e
* there is one caveat, if the device disables the parallel port or any * there is one caveat, if the device disables the parallel port or any
* of the UARTs we won't be able to detect it. * of the UARTs we won't be able to detect it.
* Nb. This could be done with accuracy by reading the SID registers, but * NB. This could be done with accuracy by reading the SID registers,
* we don't have access to those io regions. * but we don't have access to those io regions.
*/ */
unsigned char reg; unsigned char reg;
@@ -332,7 +350,8 @@ static struct pnp_device_id scl200wdt_pnp_devices[] = {
{.id = ""}, {.id = ""},
}; };
static int scl200wdt_pnp_probe(struct pnp_dev * dev, const struct pnp_device_id *dev_id) static int scl200wdt_pnp_probe(struct pnp_dev *dev,
const struct pnp_device_id *dev_id)
{ {
/* this driver only supports one card at a time */ /* this driver only supports one card at a time */
if (wdt_dev || !isapnp) if (wdt_dev || !isapnp)
@@ -347,7 +366,8 @@ static int scl200wdt_pnp_probe(struct pnp_dev * dev, const struct pnp_device_id
return -EBUSY; return -EBUSY;
} }
printk(KERN_INFO "scl200wdt: PnP device found at io port %#x/%d\n", io, io_len); printk(KERN_INFO "scl200wdt: PnP device found at io port %#x/%d\n",
io, io_len);
return 0; return 0;
} }
@@ -375,8 +395,6 @@ static int __init sc1200wdt_init(void)
printk("%s\n", banner); printk("%s\n", banner);
sema_init(&open_sem, 1);
#if defined CONFIG_PNP #if defined CONFIG_PNP
if (isapnp) { if (isapnp) {
ret = pnp_register_driver(&scl200wdt_pnp_driver); ret = pnp_register_driver(&scl200wdt_pnp_driver);
@@ -410,13 +428,16 @@ static int __init sc1200wdt_init(void)
ret = register_reboot_notifier(&sc1200wdt_notifier); ret = register_reboot_notifier(&sc1200wdt_notifier);
if (ret) { if (ret) {
printk(KERN_ERR PFX "Unable to register reboot notifier err = %d\n", ret); printk(KERN_ERR PFX
"Unable to register reboot notifier err = %d\n", ret);
goto out_io; goto out_io;
} }
ret = misc_register(&sc1200wdt_miscdev); ret = misc_register(&sc1200wdt_miscdev);
if (ret) { if (ret) {
printk(KERN_ERR PFX "Unable to register miscdev on minor %d\n", WATCHDOG_MINOR); printk(KERN_ERR PFX
"Unable to register miscdev on minor %d\n",
WATCHDOG_MINOR);
goto out_rbt; goto out_rbt;
} }