- 根目录:
- drivers
- watchdog
- ts72xx_wdt.c
/*
* Watchdog driver for Technologic Systems TS-72xx based SBCs
* (TS-7200, TS-7250 and TS-7260). These boards have external
* glue logic CPLD chip, which includes programmable watchdog
* timer.
*
* Copyright (c) 2009 Mika Westerberg <mika.westerberg@iki.fi>
*
* This driver is based on ep93xx_wdt and wm831x_wdt drivers.
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
*/
#include <linux/fs.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/miscdevice.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/watchdog.h>
#include <linux/uaccess.h>
#define TS72XX_WDT_FEED_VAL 0x05
#define TS72XX_WDT_DEFAULT_TIMEOUT 8
static int timeout = TS72XX_WDT_DEFAULT_TIMEOUT;
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. "
"(1 <= timeout <= 8, default="
__MODULE_STRING(TS72XX_WDT_DEFAULT_TIMEOUT)
")");
static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
/**
* struct ts72xx_wdt - watchdog control structure
* @lock: lock that protects this structure
* @regval: watchdog timeout value suitable for control register
* @flags: flags controlling watchdog device state
* @control_reg: watchdog control register
* @feed_reg: watchdog feed register
* @pdev: back pointer to platform dev
*/
struct ts72xx_wdt {
struct mutex lock;
int regval;
#define TS72XX_WDT_BUSY_FLAG 1
#define TS72XX_WDT_EXPECT_CLOSE_FLAG 2
int flags;
void __iomem *control_reg;
void __iomem *feed_reg;
struct platform_device *pdev;
};
static struct platform_device *ts72xx_wdt_pdev;
/*
* TS-72xx Watchdog supports following timeouts (value written
* to control register):
* value description
* -------------------------
* 0x00 watchdog disabled
* 0x01 250ms
* 0x02 500ms
* 0x03 1s
* 0x04 reserved
* 0x05 2s
* 0x06 4s
* 0x07 8s
*
* Timeouts below 1s are not very usable so we don't
* allow them at all.
*
* We provide two functions that convert between these:
* timeout_to_regval() and regval_to_timeout().
*/
static const struct {
int timeout;
int regval;
} ts72xx_wdt_map[] = {
{ 1, 3 },
{ 2, 5 },
{ 4, 6 },
{ 8, 7 },
};
/**
* timeout_to_regval() - converts given timeout to control register value
* @new_timeout: timeout in seconds to be converted
*
* Function converts given @new_timeout into valid value that can
* be programmed into watchdog control register. When conversion is
* not possible, function returns %-EINVAL.
*/
static int timeout_to_regval(int new_timeout)
{
int i;
/* first limit it to 1 - 8 seconds */
new_timeout = clamp_val(new_timeout, 1, 8);
for (i = 0; i < ARRAY_SIZE(ts72xx_wdt_map); i++) {
if (ts72xx_wdt_map[i].timeout >= new_timeout)
return ts72xx_wdt_map[i].regval;
}
return -EINVAL;
}
/**
* regval_to_timeout() - converts control register value to timeout
* @regval: control register value to be converted
*
* Function converts given @regval to timeout in seconds (1, 2, 4 or 8).
* If @regval cannot be converted, function returns %-EINVAL.
*/
static int regval_to_timeout(int regval)
{
int i;
for (i = 0; i < ARRAY_SIZE(ts72xx_wdt_map); i++) {
if (ts72xx_wdt_map[i].regval == regval)
return ts72xx_wdt_map[i].timeout;
}
return -EINVAL;
}
/**
* ts72xx_wdt_kick() - kick the watchdog
* @wdt: watchdog to be kicked
*
* Called with @wdt->lock held.
*/
static inline void ts72xx_wdt_kick(struct ts72xx_wdt *wdt)
{
__raw_writeb(TS72XX_WDT_FEED_VAL, wdt->feed_reg);
}
/**
* ts72xx_wdt_start() - starts the watchdog timer
* @wdt: watchdog to be started
*
* This function programs timeout to watchdog timer
* and starts it.
*
* Called with @wdt->lock held.
*/
static void ts72xx_wdt_start(struct ts72xx_wdt *wdt)
{
/*
* To program the wdt, it first must be "fed" and
* only after that (within 30 usecs) the configuration
* can be changed.
*/
ts72xx_wdt_kick(wdt);
__raw_writeb((u8)wdt->regval, wdt->control_reg);
}
/**
* ts72xx_wdt_stop() - stops the watchdog timer
* @wdt: watchdog to be stopped
*
* Called with @wdt->lock held.
*/
static void ts72xx_wdt_stop(struct ts72xx_wdt *wdt)
{
ts72xx_wdt_kick(wdt);
__raw_writeb(0, wdt->control_reg);
}
static int ts72xx_wdt_open(struct inode *inode, struct file *file)
{
struct ts72xx_wdt *wdt = platform_get_drvdata(ts72xx_wdt_pdev);
int regval;
/*
* Try to convert default timeout to valid register
* value first.
*/
regval = timeout_to_regval(timeout);
if (regval < 0) {
dev_err(&wdt->pdev->dev,
"failed to convert timeout (%d) to register value\n",
timeout);
return regval;
}
if (mutex_lock_interruptible(&wdt->lock))
return -ERESTARTSYS;
if ((wdt->flags & TS72XX_WDT_BUSY_FLAG) != 0) {
mutex_unlock(&wdt->lock);
return -EBUSY;
}
wdt->flags = TS72XX_WDT_BUSY_FLAG;
wdt->regval = regval;
file->private_data = wdt;
ts72xx_wdt_start(wdt);
mutex_unlock(&wdt->lock);
return nonseekable_open(inode, file);
}
static int ts72xx_wdt_release(struct inode *inode, struct file *file)
{
struct ts72xx_wdt *wdt = file->private_data;
if (mutex_lock_interruptible(&wdt->lock))
return -ERESTARTSYS;
if ((wdt->flags & TS72XX_WDT_EXPECT_CLOSE_FLAG) != 0) {
ts72xx_wdt_stop(wdt);
} else {
dev_warn(&wdt->pdev->dev,
"TS-72XX WDT device closed unexpectly. "
"Watchdog timer will not stop!\n");
/*
* Kick it one more time, to give userland some time
* to recover (for example, respawning the kicker
* daemon).
*/
ts72xx_wdt_kick(wdt);
}
wdt->flags = 0;
mutex_unlock(&wdt->lock);
return 0;
}
static ssize_t ts72xx_wdt_write(struct file *file,
const char __user *data,
size_t len,
loff_t *ppos)
{
struct ts72xx_wdt *wdt = file->private_data;
if (!len)
return 0;
if (mutex_lock_interruptible(&wdt->lock))
return -ERESTARTSYS;
ts72xx_wdt_kick(wdt);
/*
* Support for magic character closing. User process
* writes 'V' into the device, just before it is closed.
* This means that we know that the wdt timer can be
* stopped after user closes the device.
*/
if (!nowayout) {
int i;
for (i = 0; i < len; i++) {
char c;
/* In case it was set long ago */
wdt->flags &= ~TS72XX_WDT_EXPECT_CLOSE_FLAG;
if (get_user(c, data + i)) {
mutex_unlock(&wdt->lock);
return -EFAULT;
}
if (c == 'V') {
wdt->flags |= TS72XX_WDT_EXPECT_CLOSE_FLAG;
break;
}
}
}
mutex_unlock(&wdt->lock);
return len;
}
static const struct watchdog_info winfo = {
.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
WDIOF_MAGICCLOSE,
.firmware_version = 1,
.identity = "TS-72XX WDT",
};
static long ts72xx_wdt_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
struct ts72xx_wdt *wdt = file->private_data;
void __user *argp = (void __user *)arg;
int __user *p = (int __user *)argp;
int error = 0;
if (mutex_lock_interruptible(&wdt->lock))
return -ERESTARTSYS;
switch (cmd) {
case WDIOC_GETSUPPORT:
if (copy_to_user(argp, &winfo, sizeof(winfo)))
error = -EFAULT;
break;
case WDIOC_GETSTATUS:
case WDIOC_GETBOOTSTATUS:
error = put_user(0, p);
break;
case WDIOC_KEEPALIVE:
ts72xx_wdt_kick(wdt);
break;
case WDIOC_SETOPTIONS: {
int options;
error = get_user(options, p);
if (error)
break;
error = -EINVAL;
if ((options & WDIOS_DISABLECARD) != 0) {
ts72xx_wdt_stop(wdt);
error = 0;
}
if ((options & WDIOS_ENABLECARD) != 0) {
ts72xx_wdt_start(wdt);
error = 0;
}
break;
}
case WDIOC_SETTIMEOUT: {
int new_timeout;
int regval;
error = get_user(new_timeout, p);
if (error)
break;
regval = timeout_to_regval(new_timeout);
if (regval < 0) {
error = regval;
break;
}
ts72xx_wdt_stop(wdt);
wdt->regval = regval;
ts72xx_wdt_start(wdt);
/*FALLTHROUGH*/
}
case WDIOC_GETTIMEOUT:
error = put_user(regval_to_timeout(wdt->regval), p);
break;
default:
error = -ENOTTY;
break;
}
mutex_unlock(&wdt->lock);
return error;
}
static const struct file_operations ts72xx_wdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.open = ts72xx_wdt_open,
.release = ts72xx_wdt_release,
.write = ts72xx_wdt_write,
.unlocked_ioctl = ts72xx_wdt_ioctl,
};
static struct miscdevice ts72xx_wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &ts72xx_wdt_fops,
};
static int ts72xx_wdt_probe(struct platform_device *pdev)
{
struct ts72xx_wdt *wdt;
struct resource *r1, *r2;
int error = 0;
wdt = devm_kzalloc(&pdev->dev, sizeof(struct ts72xx_wdt), GFP_KERNEL);
if (!wdt)
return -ENOMEM;
r1 = platform_get_resource(pdev, IORESOURCE_MEM, 0);
wdt->control_reg = devm_ioremap_resource(&pdev->dev, r1);
if (IS_ERR(wdt->control_reg))
return PTR_ERR(wdt->control_reg);
r2 = platform_get_resource(pdev, IORESOURCE_MEM, 1);
wdt->feed_reg = devm_ioremap_resource(&pdev->dev, r2);
if (IS_ERR(wdt->feed_reg))
return PTR_ERR(wdt->feed_reg);
platform_set_drvdata(pdev, wdt);
ts72xx_wdt_pdev = pdev;
wdt->pdev = pdev;
mutex_init(&wdt->lock);
/* make sure that the watchdog is disabled */
ts72xx_wdt_stop(wdt);
error = misc_register(&ts72xx_wdt_miscdev);
if (error) {
dev_err(&pdev->dev, "failed to register miscdev\n");
return error;
}
dev_info(&pdev->dev, "TS-72xx Watchdog driver\n");
return 0;
}
static int ts72xx_wdt_remove(struct platform_device *pdev)
{
misc_deregister(&ts72xx_wdt_miscdev);
return 0;
}
static struct platform_driver ts72xx_wdt_driver = {
.probe = ts72xx_wdt_probe,
.remove = ts72xx_wdt_remove,
.driver = {
.name = "ts72xx-wdt",
},
};
module_platform_driver(ts72xx_wdt_driver);
MODULE_AUTHOR("Mika Westerberg <mika.westerberg@iki.fi>");
MODULE_DESCRIPTION("TS-72xx SBC Watchdog");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:ts72xx-wdt");