![Bryan Wu](/assets/img/avatar_default.png)
This patch implements the driver necessary use the Analog Devices Blackfin processor's on-chip watchdog controller, supports BF53[123]/BF53[467]/BF54[2489]/BF561. Signed-off-by: Mike Frysinger <michael.frysinger@analog.com> Signed-off-by: Bryan Wu <bryan.wu@analog.com> Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
491 lines
11 KiB
C
491 lines
11 KiB
C
/*
|
|
* Blackfin On-Chip Watchdog Driver
|
|
* Supports BF53[123]/BF53[467]/BF54[2489]/BF561
|
|
*
|
|
* Originally based on softdog.c
|
|
* Copyright 2006-2007 Analog Devices Inc.
|
|
* Copyright 2006-2007 Michele d'Amico
|
|
* Copyright 1996 Alan Cox <alan@redhat.com>
|
|
*
|
|
* Enter bugs at http://blackfin.uclinux.org/
|
|
*
|
|
* Licensed under the GPL-2 or later.
|
|
*/
|
|
|
|
#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/notifier.h>
|
|
#include <linux/reboot.h>
|
|
#include <linux/init.h>
|
|
#include <linux/interrupt.h>
|
|
#include <asm/blackfin.h>
|
|
#include <asm/uaccess.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"
|
|
#define PFX WATCHDOG_NAME ": "
|
|
|
|
/* 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
|
|
|
|
/* Bit in SWRST that indicates boot caused by watchdog */
|
|
#define SWRST_RESET_WDOG 0x4000
|
|
|
|
/* Bit in WDOG_CTL that indicates watchdog has expired (WDR0) */
|
|
#define WDOG_EXPIRED 0x8000
|
|
|
|
/* Masks for WDEV field in WDOG_CTL register */
|
|
#define ICTL_RESET 0x0
|
|
#define ICTL_NMI 0x2
|
|
#define ICTL_GPI 0x4
|
|
#define ICTL_NONE 0x6
|
|
#define ICTL_MASK 0x6
|
|
|
|
/* Masks for WDEN field in WDOG_CTL register */
|
|
#define WDEN_MASK 0x0FF0
|
|
#define WDEN_ENABLE 0x0000
|
|
#define WDEN_DISABLE 0x0AD0
|
|
|
|
/* some defaults */
|
|
#define WATCHDOG_TIMEOUT 20
|
|
|
|
static unsigned int timeout = WATCHDOG_TIMEOUT;
|
|
static int nowayout = WATCHDOG_NOWAYOUT;
|
|
static struct watchdog_info bfin_wdt_info;
|
|
static unsigned long open_check;
|
|
static char expect_close;
|
|
static spinlock_t bfin_wdt_spinlock = SPIN_LOCK_UNLOCKED;
|
|
|
|
/**
|
|
* 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;
|
|
unsigned long flags;
|
|
|
|
stampit();
|
|
|
|
cnt = t * get_sclk();
|
|
if (cnt < get_sclk()) {
|
|
printk(KERN_WARNING PFX "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 {
|
|
printk(KERN_CRIT PFX "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
|
|
* @inode: inode of 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 int bfin_wdt_ioctl(struct inode *inode, struct file *file,
|
|
unsigned int cmd, unsigned long arg)
|
|
{
|
|
void __user *argp = (void __user *)arg;
|
|
int __user *p = argp;
|
|
|
|
stampit();
|
|
|
|
switch (cmd) {
|
|
default:
|
|
return -ENOTTY;
|
|
|
|
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_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);
|
|
|
|
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;
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* bfin_wdt_notify_sys - Notifier Handler
|
|
* @this: notifier block
|
|
* @code: notifier event
|
|
* @unused: unused
|
|
*
|
|
* Handles specific events, such as turning off the watchdog during a
|
|
* shutdown event.
|
|
*/
|
|
static int bfin_wdt_notify_sys(struct notifier_block *this, unsigned long code,
|
|
void *unused)
|
|
{
|
|
stampit();
|
|
|
|
if (code == SYS_DOWN || code == SYS_HALT)
|
|
bfin_wdt_stop();
|
|
|
|
return NOTIFY_DONE;
|
|
}
|
|
|
|
#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 struct platform_device bfin_wdt_device = {
|
|
.name = WATCHDOG_NAME,
|
|
.id = -1,
|
|
};
|
|
|
|
static struct platform_driver bfin_wdt_driver = {
|
|
.driver = {
|
|
.name = WATCHDOG_NAME,
|
|
.owner = THIS_MODULE,
|
|
},
|
|
.suspend = bfin_wdt_suspend,
|
|
.resume = bfin_wdt_resume,
|
|
};
|
|
|
|
static struct file_operations bfin_wdt_fops = {
|
|
.owner = THIS_MODULE,
|
|
.llseek = no_llseek,
|
|
.write = bfin_wdt_write,
|
|
.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 struct watchdog_info bfin_wdt_info = {
|
|
.identity = "Blackfin Watchdog",
|
|
.options = WDIOF_SETTIMEOUT |
|
|
WDIOF_KEEPALIVEPING |
|
|
WDIOF_MAGICCLOSE,
|
|
};
|
|
|
|
static struct notifier_block bfin_wdt_notifier = {
|
|
.notifier_call = bfin_wdt_notify_sys,
|
|
};
|
|
|
|
/**
|
|
* bfin_wdt_init - Initialize module
|
|
*
|
|
* Registers the device and notifier handler. Actual device
|
|
* initialization is handled by bfin_wdt_open().
|
|
*/
|
|
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_device_register(&bfin_wdt_device);
|
|
if (ret)
|
|
return ret;
|
|
|
|
ret = platform_driver_probe(&bfin_wdt_driver, NULL);
|
|
if (ret)
|
|
return ret;
|
|
|
|
ret = register_reboot_notifier(&bfin_wdt_notifier);
|
|
if (ret) {
|
|
printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n", ret);
|
|
return ret;
|
|
}
|
|
|
|
ret = misc_register(&bfin_wdt_miscdev);
|
|
if (ret) {
|
|
printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
|
|
WATCHDOG_MINOR, ret);
|
|
unregister_reboot_notifier(&bfin_wdt_notifier);
|
|
return ret;
|
|
}
|
|
|
|
printk(KERN_INFO PFX "initialized: timeout=%d sec (nowayout=%d)\n",
|
|
timeout, nowayout);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* bfin_wdt_exit - Deinitialize module
|
|
*
|
|
* Unregisters the device and notifier handler. Actual device
|
|
* deinitialization is handled by bfin_wdt_close().
|
|
*/
|
|
static void __exit bfin_wdt_exit(void)
|
|
{
|
|
misc_deregister(&bfin_wdt_miscdev);
|
|
unregister_reboot_notifier(&bfin_wdt_notifier);
|
|
}
|
|
|
|
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, int, 0);
|
|
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
|