/*
* Watchdog driver for Atmel AT32AP700X devices
*
* Copyright (C) 2005-2006 Atmel Corporation
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/miscdevice.h>
#include <linux/fs.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#define TIMEOUT_MIN 1
#define TIMEOUT_DEFAULT CONFIG_AT32AP700X_WDT_TIMEOUT
#define TIMEOUT_MAX 2
/* Watchdog registers and write/read macro */
#define WDT_CTRL 0x00
#define WDT_CTRL_EN 0
#define WDT_CTRL_PSEL 8
#define WDT_CTRL_KEY 24
#define WDT_CLR 0x04
#define WDT_BIT(name) (1 << WDT_##name)
#define WDT_BF(name,value) ((value) << WDT_##name)
#define wdt_readl(dev,reg) \
__raw_readl((dev)->regs + WDT_##reg)
#define wdt_writel(dev,reg,value) \
__raw_writel((value), (dev)->regs + WDT_##reg)
struct wdt_at32ap700x {
void __iomem *regs;
int timeout;
int users;
struct miscdevice miscdev;
};
static struct wdt_at32ap700x *wdt;
/*
* Disable the watchdog.
*/
static void inline at32_wdt_stop(void)
{
unsigned long psel = wdt_readl(wdt, CTRL) & WDT_BF(CTRL_PSEL, 0x0f);
wdt_writel(wdt, CTRL, psel | WDT_BF(CTRL_KEY, 0x55));
wdt_writel(wdt, CTRL, psel | WDT_BF(CTRL_KEY, 0xaa));
}
/*
* Enable and reset the watchdog.
*/
static void inline at32_wdt_start(void)
{
/* 0xf is 2^16 divider = 2 sec, 0xe is 2^15 divider = 1 sec */
unsigned long psel = (wdt->timeout > 1) ? 0xf : 0xe;
wdt_writel(wdt, CTRL, WDT_BIT(CTRL_EN)
| WDT_BF(CTRL_PSEL, psel)
| WDT_BF(CTRL_KEY, 0x55));
wdt_writel(wdt, CTRL, WDT_BIT(CTRL_EN)
| WDT_BF(CTRL_PSEL, psel)
| WDT_BF(CTRL_KEY, 0xaa));
}
/*
* Pat the watchdog timer.
*/
static void inline at32_wdt_pat(void)
{
wdt_writel(wdt, CLR, 0x42);
}
/*
* Watchdog device is opened, and watchdog starts running.
*/
static int at32_wdt_open(struct inode *inode, struct file *file)
{
if (test_and_set_bit(1, &wdt->users))
return -EBUSY;
at32_wdt_start();
return nonseekable_open(inode, file);
}
/*
* Close the watchdog device. If CONFIG_WATCHDOG_NOWAYOUT is _not_ defined then
* the watchdog is also disabled.
*/
static int at32_wdt_close(struct inode *inode, struct file *file)
{
#ifndef CONFIG_WATCHDOG_NOWAYOUT
at32_wdt_stop();
#endif
clear_bit(1, &wdt->users);
return 0;
}
/*
* Change the watchdog time interval.
*/
static int at32_wdt_settimeout(int time)
{
/*
* All counting occurs at 1 / SLOW_CLOCK (32 kHz) and max prescaler is
* 2 ^ 16 allowing up to 2 seconds timeout.
*/
if ((time < TIMEOUT_MIN) || (time > TIMEOUT_MAX))
return -EINVAL;
/*
* Set new watchdog time. It will be used when at32_wdt_start() is
* called.
*/
wdt->timeout = time;
return 0;
}
static struct watchdog_info at32_wdt_info = {
.identity = "at32ap700x watchdog",
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
};
/*
* Handle commands from user-space.
*/
static int at32_wdt_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg)
{
int ret = -ENOTTY;
int time;
void __user *argp = (void __user *)arg;
int __user *p = argp;
switch (cmd) {
case WDIOC_KEEPALIVE:
at32_wdt_pat();
ret = 0;
break;
case WDIOC_GETSUPPORT:
ret = copy_to_user(argp, &at32_wdt_info,
sizeof(at32_wdt_info)) ? -EFAULT : 0;
break;
case WDIOC_SETTIMEOUT:
ret = get_user(time, p);
if (ret)
break;
ret = at32_wdt_settimeout(time);
if (ret)
break;
/* Enable new time value */
at32_wdt_start();
/* fall through */
case WDIOC_GETTIMEOUT:
ret = put_user(wdt->timeout, p);
break;
case WDIOC_GETSTATUS: /* fall through */
case WDIOC_GETBOOTSTATUS:
ret = put_user(0, p);
break;
case WDIOC_SETOPTIONS:
ret = get_user(time, p);
if (ret)
break;
if (time & WDIOS_DISABLECARD)
at32_wdt_stop();
if (time & WDIOS_ENABLECARD)
at32_wdt_start();
ret = 0;
break;
}
return ret;
}
static ssize_t at32_wdt_write(struct file *file, const char *data, size_t len,
loff_t *ppos)
{
at32_wdt_pat();
return len;
}
static const struct file_operations at32_wdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.ioctl = at32_wdt_ioctl,
.open = at32_wdt_open,
.release = at32_wdt_close,
.write = at32_wdt_write,
};
static int __init at32_wdt_probe(struct platform_device *pdev)
{
struct resource *regs;
int ret;
if (wdt) {
dev_dbg(&pdev->dev, "only 1 wdt instance supported.\n");
return -EBUSY;
}
regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!regs) {
dev_dbg(&pdev->dev, "missing mmio resource\n");
return -ENXIO;
}
wdt = kzalloc(sizeof(struct wdt_at32ap700x), GFP_KERNEL);
if (!wdt) {
dev_dbg(&pdev->dev, "no memory for wdt structure\n");
return -ENOMEM;
}
wdt->regs = ioremap(regs->start, regs->end - regs->start + 1);
if (!wdt->regs) {
ret = -ENOMEM;
dev_dbg(&pdev->dev, "could not map I/O memory\n");
goto err_free;
}
wdt->users = 0;
wdt->miscdev.minor = WATCHDOG_MINOR;
wdt->miscdev.name = "watchdog";
wdt->miscdev.fops = &at32_wdt_fops;
if (at32_wdt_settimeout(TIMEOUT_DEFAULT)) {
at32_wdt_settimeout(TIMEOUT_MAX);
dev_dbg(&pdev->dev,
"default timeout invalid, set to %d sec.\n",
TIMEOUT_MAX);
}
ret = misc_register(&wdt->miscdev);
if (ret) {
dev_dbg(&pdev->dev, "failed to register wdt miscdev\n");
goto err_iounmap;
}
platform_set_drvdata(pdev, wdt);
wdt->miscdev.parent = &pdev->dev;
dev_info(&pdev->dev, "AT32AP700X WDT at 0x%p\n", wdt->regs);
return 0;
err_iounmap:
iounmap(wdt->regs);
err_free:
kfree(wdt);
wdt = NULL;
return ret;
}
static int __exit at32_wdt_remove(struct platform_device *pdev)
{
if (wdt && platform_get_drvdata(pdev) == wdt) {
misc_deregister(&wdt->miscdev);
iounmap(wdt->regs);
kfree(wdt);
wdt = NULL;
platform_set_drvdata(pdev, NULL);
}
return 0;
}
static void at32_wdt_shutdown(struct platform_device *pdev)
{
at32_wdt_stop();
}
#ifdef CONFIG_PM
static int at32_wdt_suspend(struct platform_device *pdev, pm_message_t message)
{
at32_wdt_stop();
return 0;
}
static int at32_wdt_resume(struct platform_device *pdev)
{
if (wdt->users)
at32_wdt_start();
return 0;
}
#else
#define at32_wdt_suspend NULL
#define at32_wdt_resume NULL
#endif
static struct platform_driver at32_wdt_driver = {
.remove = __exit_p(at32_wdt_remove),
.suspend = at32_wdt_suspend,
.resume = at32_wdt_resume,
.driver = {
.name = "at32_wdt",
.owner = THIS_MODULE,
},
.shutdown = at32_wdt_shutdown,
};
static int __init at32_wdt_init(void)
{
return platform_driver_probe(&at32_wdt_driver, at32_wdt_probe);
}
module_init(at32_wdt_init);
static void __exit at32_wdt_exit(void)
{
platform_driver_unregister(&at32_wdt_driver);
}
module_exit(at32_wdt_exit);
MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>");
MODULE_DESCRIPTION("Watchdog driver for Atmel AT32AP700X");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
