479 lines
10 KiB
C
479 lines
10 KiB
C
/*
|
|
* Blackfin On-Chip Watchdog Driver
|
|
*
|
|
* Originally based on softdog.c
|
|
* Copyright 2006-2010 Analog Devices Inc.
|
|
* Copyright 2006-2007 Michele d'Amico
|
|
* Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>
|
|
*
|
|
* Enter bugs at http://blackfin.uclinux.org/
|
|
*
|
|
* Licensed under the GPL-2 or later.
|
|
*/
|
|
|
|
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
|
|
|
|
#include <linux/platform_device.h>
|
|
#include <linux/module.h>
|
|
#include <linux/moduleparam.h>
|
|
#include <linux/types.h>
|
|
#include <linux/timer.h>
|
|
#include <linux/miscdevice.h>
|
|
#include <linux/watchdog.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/init.h>
|
|
#include <linux/interrupt.h>
|
|
#include <linux/uaccess.h>
|
|
#include <asm/blackfin.h>
|
|
#include <asm/bfin_watchdog.h>
|
|
|
|
#define stamp(fmt, args...) \
|
|
pr_debug("%s:%i: " fmt "\n", __func__, __LINE__, ## args)
|
|
#define stampit() stamp("here i am")
|
|
|
|
#define WATCHDOG_NAME "bfin-wdt"
|
|
|
|
/* The BF561 has two watchdogs (one per core), but since Linux
|
|
* only runs on core A, we'll just work with that one.
|
|
*/
|
|
#ifdef BF561_FAMILY
|
|
# define bfin_read_WDOG_CTL() bfin_read_WDOGA_CTL()
|
|
# define bfin_read_WDOG_CNT() bfin_read_WDOGA_CNT()
|
|
# define bfin_read_WDOG_STAT() bfin_read_WDOGA_STAT()
|
|
# define bfin_write_WDOG_CTL(x) bfin_write_WDOGA_CTL(x)
|
|
# define bfin_write_WDOG_CNT(x) bfin_write_WDOGA_CNT(x)
|
|
# define bfin_write_WDOG_STAT(x) bfin_write_WDOGA_STAT(x)
|
|
#endif
|
|
|
|
/* some defaults */
|
|
#define WATCHDOG_TIMEOUT 20
|
|
|
|
static unsigned int timeout = WATCHDOG_TIMEOUT;
|
|
static bool nowayout = WATCHDOG_NOWAYOUT;
|
|
static const struct watchdog_info bfin_wdt_info;
|
|
static unsigned long open_check;
|
|
static char expect_close;
|
|
static DEFINE_SPINLOCK(bfin_wdt_spinlock);
|
|
|
|
/**
|
|
* bfin_wdt_keepalive - Keep the Userspace Watchdog Alive
|
|
*
|
|
* The Userspace watchdog got a KeepAlive: schedule the next timeout.
|
|
*/
|
|
static int bfin_wdt_keepalive(void)
|
|
{
|
|
stampit();
|
|
bfin_write_WDOG_STAT(0);
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* bfin_wdt_stop - Stop the Watchdog
|
|
*
|
|
* Stops the on-chip watchdog.
|
|
*/
|
|
static int bfin_wdt_stop(void)
|
|
{
|
|
stampit();
|
|
bfin_write_WDOG_CTL(WDEN_DISABLE);
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* bfin_wdt_start - Start the Watchdog
|
|
*
|
|
* Starts the on-chip watchdog. Automatically loads WDOG_CNT
|
|
* into WDOG_STAT for us.
|
|
*/
|
|
static int bfin_wdt_start(void)
|
|
{
|
|
stampit();
|
|
bfin_write_WDOG_CTL(WDEN_ENABLE | ICTL_RESET);
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* bfin_wdt_running - Check Watchdog status
|
|
*
|
|
* See if the watchdog is running.
|
|
*/
|
|
static int bfin_wdt_running(void)
|
|
{
|
|
stampit();
|
|
return ((bfin_read_WDOG_CTL() & WDEN_MASK) != WDEN_DISABLE);
|
|
}
|
|
|
|
/**
|
|
* bfin_wdt_set_timeout - Set the Userspace Watchdog timeout
|
|
* @t: new timeout value (in seconds)
|
|
*
|
|
* Translate the specified timeout in seconds into System Clock
|
|
* terms which is what the on-chip Watchdog requires.
|
|
*/
|
|
static int bfin_wdt_set_timeout(unsigned long t)
|
|
{
|
|
u32 cnt, max_t, sclk;
|
|
unsigned long flags;
|
|
|
|
sclk = get_sclk();
|
|
max_t = -1 / sclk;
|
|
cnt = t * sclk;
|
|
stamp("maxtimeout=%us newtimeout=%lus (cnt=%#x)", max_t, t, cnt);
|
|
|
|
if (t > max_t) {
|
|
pr_warn("timeout value is too large\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
spin_lock_irqsave(&bfin_wdt_spinlock, flags);
|
|
{
|
|
int run = bfin_wdt_running();
|
|
bfin_wdt_stop();
|
|
bfin_write_WDOG_CNT(cnt);
|
|
if (run)
|
|
bfin_wdt_start();
|
|
}
|
|
spin_unlock_irqrestore(&bfin_wdt_spinlock, flags);
|
|
|
|
timeout = t;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* bfin_wdt_open - Open the Device
|
|
* @inode: inode of device
|
|
* @file: file handle of device
|
|
*
|
|
* Watchdog device is opened and started.
|
|
*/
|
|
static int bfin_wdt_open(struct inode *inode, struct file *file)
|
|
{
|
|
stampit();
|
|
|
|
if (test_and_set_bit(0, &open_check))
|
|
return -EBUSY;
|
|
|
|
if (nowayout)
|
|
__module_get(THIS_MODULE);
|
|
|
|
bfin_wdt_keepalive();
|
|
bfin_wdt_start();
|
|
|
|
return nonseekable_open(inode, file);
|
|
}
|
|
|
|
/**
|
|
* bfin_wdt_close - Close the Device
|
|
* @inode: inode of device
|
|
* @file: file handle of device
|
|
*
|
|
* Watchdog device is closed and stopped.
|
|
*/
|
|
static int bfin_wdt_release(struct inode *inode, struct file *file)
|
|
{
|
|
stampit();
|
|
|
|
if (expect_close == 42)
|
|
bfin_wdt_stop();
|
|
else {
|
|
pr_crit("Unexpected close, not stopping watchdog!\n");
|
|
bfin_wdt_keepalive();
|
|
}
|
|
expect_close = 0;
|
|
clear_bit(0, &open_check);
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* bfin_wdt_write - Write to Device
|
|
* @file: file handle of device
|
|
* @buf: buffer to write
|
|
* @count: length of buffer
|
|
* @ppos: offset
|
|
*
|
|
* Pings the watchdog on write.
|
|
*/
|
|
static ssize_t bfin_wdt_write(struct file *file, const char __user *data,
|
|
size_t len, loff_t *ppos)
|
|
{
|
|
stampit();
|
|
|
|
if (len) {
|
|
if (!nowayout) {
|
|
size_t i;
|
|
|
|
/* In case it was set long ago */
|
|
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;
|
|
}
|
|
}
|
|
bfin_wdt_keepalive();
|
|
}
|
|
|
|
return len;
|
|
}
|
|
|
|
/**
|
|
* bfin_wdt_ioctl - Query Device
|
|
* @file: file handle of device
|
|
* @cmd: watchdog command
|
|
* @arg: argument
|
|
*
|
|
* Query basic information from the device or ping it, as outlined by the
|
|
* watchdog API.
|
|
*/
|
|
static long bfin_wdt_ioctl(struct file *file,
|
|
unsigned int cmd, unsigned long arg)
|
|
{
|
|
void __user *argp = (void __user *)arg;
|
|
int __user *p = argp;
|
|
|
|
stampit();
|
|
|
|
switch (cmd) {
|
|
case WDIOC_GETSUPPORT:
|
|
if (copy_to_user(argp, &bfin_wdt_info, sizeof(bfin_wdt_info)))
|
|
return -EFAULT;
|
|
else
|
|
return 0;
|
|
case WDIOC_GETSTATUS:
|
|
case WDIOC_GETBOOTSTATUS:
|
|
return put_user(!!(_bfin_swrst & SWRST_RESET_WDOG), p);
|
|
case WDIOC_SETOPTIONS: {
|
|
unsigned long flags;
|
|
int options, ret = -EINVAL;
|
|
|
|
if (get_user(options, p))
|
|
return -EFAULT;
|
|
|
|
spin_lock_irqsave(&bfin_wdt_spinlock, flags);
|
|
if (options & WDIOS_DISABLECARD) {
|
|
bfin_wdt_stop();
|
|
ret = 0;
|
|
}
|
|
if (options & WDIOS_ENABLECARD) {
|
|
bfin_wdt_start();
|
|
ret = 0;
|
|
}
|
|
spin_unlock_irqrestore(&bfin_wdt_spinlock, flags);
|
|
return ret;
|
|
}
|
|
case WDIOC_KEEPALIVE:
|
|
bfin_wdt_keepalive();
|
|
return 0;
|
|
case WDIOC_SETTIMEOUT: {
|
|
int new_timeout;
|
|
|
|
if (get_user(new_timeout, p))
|
|
return -EFAULT;
|
|
if (bfin_wdt_set_timeout(new_timeout))
|
|
return -EINVAL;
|
|
}
|
|
/* Fall */
|
|
case WDIOC_GETTIMEOUT:
|
|
return put_user(timeout, p);
|
|
default:
|
|
return -ENOTTY;
|
|
}
|
|
}
|
|
|
|
#ifdef CONFIG_PM
|
|
static int state_before_suspend;
|
|
|
|
/**
|
|
* bfin_wdt_suspend - suspend the watchdog
|
|
* @pdev: device being suspended
|
|
* @state: requested suspend state
|
|
*
|
|
* Remember if the watchdog was running and stop it.
|
|
* TODO: is this even right? Doesn't seem to be any
|
|
* standard in the watchdog world ...
|
|
*/
|
|
static int bfin_wdt_suspend(struct platform_device *pdev, pm_message_t state)
|
|
{
|
|
stampit();
|
|
|
|
state_before_suspend = bfin_wdt_running();
|
|
bfin_wdt_stop();
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* bfin_wdt_resume - resume the watchdog
|
|
* @pdev: device being resumed
|
|
*
|
|
* If the watchdog was running, turn it back on.
|
|
*/
|
|
static int bfin_wdt_resume(struct platform_device *pdev)
|
|
{
|
|
stampit();
|
|
|
|
if (state_before_suspend) {
|
|
bfin_wdt_set_timeout(timeout);
|
|
bfin_wdt_start();
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
#else
|
|
# define bfin_wdt_suspend NULL
|
|
# define bfin_wdt_resume NULL
|
|
#endif
|
|
|
|
static const struct file_operations bfin_wdt_fops = {
|
|
.owner = THIS_MODULE,
|
|
.llseek = no_llseek,
|
|
.write = bfin_wdt_write,
|
|
.unlocked_ioctl = bfin_wdt_ioctl,
|
|
.open = bfin_wdt_open,
|
|
.release = bfin_wdt_release,
|
|
};
|
|
|
|
static struct miscdevice bfin_wdt_miscdev = {
|
|
.minor = WATCHDOG_MINOR,
|
|
.name = "watchdog",
|
|
.fops = &bfin_wdt_fops,
|
|
};
|
|
|
|
static const struct watchdog_info bfin_wdt_info = {
|
|
.identity = "Blackfin Watchdog",
|
|
.options = WDIOF_SETTIMEOUT |
|
|
WDIOF_KEEPALIVEPING |
|
|
WDIOF_MAGICCLOSE,
|
|
};
|
|
|
|
/**
|
|
* bfin_wdt_probe - Initialize module
|
|
*
|
|
* Registers the misc device. Actual device
|
|
* initialization is handled by bfin_wdt_open().
|
|
*/
|
|
static int __devinit bfin_wdt_probe(struct platform_device *pdev)
|
|
{
|
|
int ret;
|
|
|
|
ret = misc_register(&bfin_wdt_miscdev);
|
|
if (ret) {
|
|
pr_err("cannot register miscdev on minor=%d (err=%d)\n",
|
|
WATCHDOG_MINOR, ret);
|
|
return ret;
|
|
}
|
|
|
|
pr_info("initialized: timeout=%d sec (nowayout=%d)\n",
|
|
timeout, nowayout);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* bfin_wdt_remove - Initialize module
|
|
*
|
|
* Unregisters the misc device. Actual device
|
|
* deinitialization is handled by bfin_wdt_close().
|
|
*/
|
|
static int __devexit bfin_wdt_remove(struct platform_device *pdev)
|
|
{
|
|
misc_deregister(&bfin_wdt_miscdev);
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* bfin_wdt_shutdown - Soft Shutdown Handler
|
|
*
|
|
* Handles the soft shutdown event.
|
|
*/
|
|
static void bfin_wdt_shutdown(struct platform_device *pdev)
|
|
{
|
|
stampit();
|
|
|
|
bfin_wdt_stop();
|
|
}
|
|
|
|
static struct platform_device *bfin_wdt_device;
|
|
|
|
static struct platform_driver bfin_wdt_driver = {
|
|
.probe = bfin_wdt_probe,
|
|
.remove = bfin_wdt_remove,
|
|
.shutdown = bfin_wdt_shutdown,
|
|
.suspend = bfin_wdt_suspend,
|
|
.resume = bfin_wdt_resume,
|
|
.driver = {
|
|
.name = WATCHDOG_NAME,
|
|
.owner = THIS_MODULE,
|
|
},
|
|
};
|
|
|
|
/**
|
|
* bfin_wdt_init - Initialize module
|
|
*
|
|
* Checks the module params and registers the platform device & driver.
|
|
* Real work is in the platform probe function.
|
|
*/
|
|
static int __init bfin_wdt_init(void)
|
|
{
|
|
int ret;
|
|
|
|
stampit();
|
|
|
|
/* Check that the timeout value is within range */
|
|
if (bfin_wdt_set_timeout(timeout))
|
|
return -EINVAL;
|
|
|
|
/* Since this is an on-chip device and needs no board-specific
|
|
* resources, we'll handle all the platform device stuff here.
|
|
*/
|
|
ret = platform_driver_register(&bfin_wdt_driver);
|
|
if (ret) {
|
|
pr_err("unable to register driver\n");
|
|
return ret;
|
|
}
|
|
|
|
bfin_wdt_device = platform_device_register_simple(WATCHDOG_NAME,
|
|
-1, NULL, 0);
|
|
if (IS_ERR(bfin_wdt_device)) {
|
|
pr_err("unable to register device\n");
|
|
platform_driver_unregister(&bfin_wdt_driver);
|
|
return PTR_ERR(bfin_wdt_device);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* bfin_wdt_exit - Deinitialize module
|
|
*
|
|
* Back out the platform device & driver steps. Real work is in the
|
|
* platform remove function.
|
|
*/
|
|
static void __exit bfin_wdt_exit(void)
|
|
{
|
|
platform_device_unregister(bfin_wdt_device);
|
|
platform_driver_unregister(&bfin_wdt_driver);
|
|
}
|
|
|
|
module_init(bfin_wdt_init);
|
|
module_exit(bfin_wdt_exit);
|
|
|
|
MODULE_AUTHOR("Michele d'Amico, Mike Frysinger <vapier@gentoo.org>");
|
|
MODULE_DESCRIPTION("Blackfin Watchdog Device Driver");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
|
|
|
|
module_param(timeout, uint, 0);
|
|
MODULE_PARM_DESC(timeout,
|
|
"Watchdog timeout in seconds. (1<=timeout<=((2^32)/SCLK), default="
|
|
__MODULE_STRING(WATCHDOG_TIMEOUT) ")");
|
|
|
|
module_param(nowayout, bool, 0);
|
|
MODULE_PARM_DESC(nowayout,
|
|
"Watchdog cannot be stopped once started (default="
|
|
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
|