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Wan ZongShun
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Wim Van Sebroeck
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Sep 18, 2009
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refs/heads/master: 3a5f90002e9d08e5a6406fc650bfd838bf23bc1b | ||
refs/heads/master: 0400e3134b03336617138f9ebf2cd0f117ceef20 |
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/* | ||
* Copyright (c) 2009 Nuvoton technology corporation. | ||
* | ||
* Wan ZongShun <mcuos.com@gmail.com> | ||
* | ||
* This program is free software; you can redistribute it and/or modify | ||
* it under the terms of the GNU General Public License as published by | ||
* the Free Software Foundation;version 2 of the License. | ||
* | ||
*/ | ||
|
||
#include <linux/bitops.h> | ||
#include <linux/errno.h> | ||
#include <linux/fs.h> | ||
#include <linux/init.h> | ||
#include <linux/io.h> | ||
#include <linux/clk.h> | ||
#include <linux/kernel.h> | ||
#include <linux/miscdevice.h> | ||
#include <linux/module.h> | ||
#include <linux/moduleparam.h> | ||
#include <linux/platform_device.h> | ||
#include <linux/interrupt.h> | ||
#include <linux/types.h> | ||
#include <linux/watchdog.h> | ||
#include <linux/uaccess.h> | ||
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#define REG_WTCR 0x1c | ||
#define WTCLK (0x01 << 10) | ||
#define WTE (0x01 << 7) /*wdt enable*/ | ||
#define WTIS (0x03 << 4) | ||
#define WTIF (0x01 << 3) | ||
#define WTRF (0x01 << 2) | ||
#define WTRE (0x01 << 1) | ||
#define WTR (0x01 << 0) | ||
/* | ||
* The watchdog time interval can be calculated via following formula: | ||
* WTIS real time interval (formula) | ||
* 0x00 ((2^ 14 ) * ((external crystal freq) / 256))seconds | ||
* 0x01 ((2^ 16 ) * ((external crystal freq) / 256))seconds | ||
* 0x02 ((2^ 18 ) * ((external crystal freq) / 256))seconds | ||
* 0x03 ((2^ 20 ) * ((external crystal freq) / 256))seconds | ||
* | ||
* The external crystal freq is 15Mhz in the nuc900 evaluation board. | ||
* So 0x00 = +-0.28 seconds, 0x01 = +-1.12 seconds, 0x02 = +-4.48 seconds, | ||
* 0x03 = +- 16.92 seconds.. | ||
*/ | ||
#define WDT_HW_TIMEOUT 0x02 | ||
#define WDT_TIMEOUT (HZ/2) | ||
#define WDT_HEARTBEAT 15 | ||
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static int heartbeat = WDT_HEARTBEAT; | ||
module_param(heartbeat, int, 0); | ||
MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds. " | ||
"(default = " __MODULE_STRING(WDT_HEARTBEAT) ")"); | ||
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static int nowayout = WATCHDOG_NOWAYOUT; | ||
module_param(nowayout, int, 0); | ||
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started " | ||
"(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | ||
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struct nuc900_wdt { | ||
struct resource *res; | ||
struct clk *wdt_clock; | ||
struct platform_device *pdev; | ||
void __iomem *wdt_base; | ||
char expect_close; | ||
struct timer_list timer; | ||
spinlock_t wdt_lock; | ||
unsigned long next_heartbeat; | ||
}; | ||
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static unsigned long nuc900wdt_busy; | ||
struct nuc900_wdt *nuc900_wdt; | ||
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static inline void nuc900_wdt_keepalive(void) | ||
{ | ||
unsigned int val; | ||
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spin_lock(&nuc900_wdt->wdt_lock); | ||
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val = __raw_readl(nuc900_wdt->wdt_base + REG_WTCR); | ||
val |= (WTR | WTIF); | ||
__raw_writel(val, nuc900_wdt->wdt_base + REG_WTCR); | ||
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spin_unlock(&nuc900_wdt->wdt_lock); | ||
} | ||
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static inline void nuc900_wdt_start(void) | ||
{ | ||
unsigned int val; | ||
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spin_lock(&nuc900_wdt->wdt_lock); | ||
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val = __raw_readl(nuc900_wdt->wdt_base + REG_WTCR); | ||
val |= (WTRE | WTE | WTR | WTCLK | WTIF); | ||
val &= ~WTIS; | ||
val |= (WDT_HW_TIMEOUT << 0x04); | ||
__raw_writel(val, nuc900_wdt->wdt_base + REG_WTCR); | ||
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spin_unlock(&nuc900_wdt->wdt_lock); | ||
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nuc900_wdt->next_heartbeat = jiffies + heartbeat * HZ; | ||
mod_timer(&nuc900_wdt->timer, jiffies + WDT_TIMEOUT); | ||
} | ||
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static inline void nuc900_wdt_stop(void) | ||
{ | ||
unsigned int val; | ||
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del_timer(&nuc900_wdt->timer); | ||
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spin_lock(&nuc900_wdt->wdt_lock); | ||
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val = __raw_readl(nuc900_wdt->wdt_base + REG_WTCR); | ||
val &= ~WTE; | ||
__raw_writel(val, nuc900_wdt->wdt_base + REG_WTCR); | ||
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spin_unlock(&nuc900_wdt->wdt_lock); | ||
} | ||
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static inline void nuc900_wdt_ping(void) | ||
{ | ||
nuc900_wdt->next_heartbeat = jiffies + heartbeat * HZ; | ||
} | ||
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static int nuc900_wdt_open(struct inode *inode, struct file *file) | ||
{ | ||
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if (test_and_set_bit(0, &nuc900wdt_busy)) | ||
return -EBUSY; | ||
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nuc900_wdt_start(); | ||
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return nonseekable_open(inode, file); | ||
} | ||
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static int nuc900_wdt_close(struct inode *inode, struct file *file) | ||
{ | ||
if (nuc900_wdt->expect_close == 42) | ||
nuc900_wdt_stop(); | ||
else { | ||
dev_crit(&nuc900_wdt->pdev->dev, | ||
"Unexpected close, not stopping watchdog!\n"); | ||
nuc900_wdt_ping(); | ||
} | ||
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nuc900_wdt->expect_close = 0; | ||
clear_bit(0, &nuc900wdt_busy); | ||
return 0; | ||
} | ||
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static const struct watchdog_info nuc900_wdt_info = { | ||
.identity = "nuc900 watchdog", | ||
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | | ||
WDIOF_MAGICCLOSE, | ||
}; | ||
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static long nuc900_wdt_ioctl(struct file *file, | ||
unsigned int cmd, unsigned long arg) | ||
{ | ||
void __user *argp = (void __user *)arg; | ||
int __user *p = argp; | ||
int new_value; | ||
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switch (cmd) { | ||
case WDIOC_GETSUPPORT: | ||
return copy_to_user(argp, &nuc900_wdt_info, | ||
sizeof(nuc900_wdt_info)) ? -EFAULT : 0; | ||
case WDIOC_GETSTATUS: | ||
case WDIOC_GETBOOTSTATUS: | ||
return put_user(0, p); | ||
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case WDIOC_KEEPALIVE: | ||
nuc900_wdt_ping(); | ||
return 0; | ||
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case WDIOC_SETTIMEOUT: | ||
if (get_user(new_value, p)) | ||
return -EFAULT; | ||
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heartbeat = new_value; | ||
nuc900_wdt_ping(); | ||
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return put_user(new_value, p); | ||
case WDIOC_GETTIMEOUT: | ||
return put_user(heartbeat, p); | ||
default: | ||
return -ENOTTY; | ||
} | ||
} | ||
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static ssize_t nuc900_wdt_write(struct file *file, const char __user *data, | ||
size_t len, loff_t *ppos) | ||
{ | ||
if (!len) | ||
return 0; | ||
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/* Scan for magic character */ | ||
if (!nowayout) { | ||
size_t i; | ||
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nuc900_wdt->expect_close = 0; | ||
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for (i = 0; i < len; i++) { | ||
char c; | ||
if (get_user(c, data + i)) | ||
return -EFAULT; | ||
if (c == 'V') { | ||
nuc900_wdt->expect_close = 42; | ||
break; | ||
} | ||
} | ||
} | ||
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nuc900_wdt_ping(); | ||
return len; | ||
} | ||
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static void nuc900_wdt_timer_ping(unsigned long data) | ||
{ | ||
if (time_before(jiffies, nuc900_wdt->next_heartbeat)) { | ||
nuc900_wdt_keepalive(); | ||
mod_timer(&nuc900_wdt->timer, jiffies + WDT_TIMEOUT); | ||
} else | ||
dev_warn(&nuc900_wdt->pdev->dev, "Will reset the machine !\n"); | ||
} | ||
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static const struct file_operations nuc900wdt_fops = { | ||
.owner = THIS_MODULE, | ||
.llseek = no_llseek, | ||
.unlocked_ioctl = nuc900_wdt_ioctl, | ||
.open = nuc900_wdt_open, | ||
.release = nuc900_wdt_close, | ||
.write = nuc900_wdt_write, | ||
}; | ||
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static struct miscdevice nuc900wdt_miscdev = { | ||
.minor = WATCHDOG_MINOR, | ||
.name = "watchdog", | ||
.fops = &nuc900wdt_fops, | ||
}; | ||
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static int __devinit nuc900wdt_probe(struct platform_device *pdev) | ||
{ | ||
int ret = 0; | ||
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nuc900_wdt = kzalloc(sizeof(struct nuc900_wdt), GFP_KERNEL); | ||
if (!nuc900_wdt) | ||
return -ENOMEM; | ||
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nuc900_wdt->pdev = pdev; | ||
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spin_lock_init(&nuc900_wdt->wdt_lock); | ||
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nuc900_wdt->res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | ||
if (nuc900_wdt->res == NULL) { | ||
dev_err(&pdev->dev, "no memory resource specified\n"); | ||
ret = -ENOENT; | ||
goto err_get; | ||
} | ||
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if (!request_mem_region(nuc900_wdt->res->start, | ||
resource_size(nuc900_wdt->res), pdev->name)) { | ||
dev_err(&pdev->dev, "failed to get memory region\n"); | ||
ret = -ENOENT; | ||
goto err_get; | ||
} | ||
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nuc900_wdt->wdt_base = ioremap(nuc900_wdt->res->start, | ||
resource_size(nuc900_wdt->res)); | ||
if (nuc900_wdt->wdt_base == NULL) { | ||
dev_err(&pdev->dev, "failed to ioremap() region\n"); | ||
ret = -EINVAL; | ||
goto err_req; | ||
} | ||
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nuc900_wdt->wdt_clock = clk_get(&pdev->dev, NULL); | ||
if (IS_ERR(nuc900_wdt->wdt_clock)) { | ||
dev_err(&pdev->dev, "failed to find watchdog clock source\n"); | ||
ret = PTR_ERR(nuc900_wdt->wdt_clock); | ||
goto err_map; | ||
} | ||
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clk_enable(nuc900_wdt->wdt_clock); | ||
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setup_timer(&nuc900_wdt->timer, nuc900_wdt_timer_ping, 0); | ||
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if (misc_register(&nuc900wdt_miscdev)) { | ||
dev_err(&pdev->dev, "err register miscdev on minor=%d (%d)\n", | ||
WATCHDOG_MINOR, ret); | ||
goto err_clk; | ||
} | ||
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return 0; | ||
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err_clk: | ||
clk_disable(nuc900_wdt->wdt_clock); | ||
clk_put(nuc900_wdt->wdt_clock); | ||
err_map: | ||
iounmap(nuc900_wdt->wdt_base); | ||
err_req: | ||
release_mem_region(nuc900_wdt->res->start, | ||
resource_size(nuc900_wdt->res)); | ||
err_get: | ||
kfree(nuc900_wdt); | ||
return ret; | ||
} | ||
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static int __devexit nuc900wdt_remove(struct platform_device *pdev) | ||
{ | ||
misc_deregister(&nuc900wdt_miscdev); | ||
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clk_disable(nuc900_wdt->wdt_clock); | ||
clk_put(nuc900_wdt->wdt_clock); | ||
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iounmap(nuc900_wdt->wdt_base); | ||
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release_mem_region(nuc900_wdt->res->start, | ||
resource_size(nuc900_wdt->res)); | ||
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kfree(nuc900_wdt); | ||
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return 0; | ||
} | ||
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static struct platform_driver nuc900wdt_driver = { | ||
.probe = nuc900wdt_probe, | ||
.remove = __devexit_p(nuc900wdt_remove), | ||
.driver = { | ||
.name = "nuc900-wdt", | ||
.owner = THIS_MODULE, | ||
}, | ||
}; | ||
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static int __init nuc900_wdt_init(void) | ||
{ | ||
return platform_driver_register(&nuc900wdt_driver); | ||
} | ||
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static void __exit nuc900_wdt_exit(void) | ||
{ | ||
platform_driver_unregister(&nuc900wdt_driver); | ||
} | ||
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module_init(nuc900_wdt_init); | ||
module_exit(nuc900_wdt_exit); | ||
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MODULE_AUTHOR("Wan ZongShun <mcuos.com@gmail.com>"); | ||
MODULE_DESCRIPTION("Watchdog driver for NUC900"); | ||
MODULE_LICENSE("GPL"); | ||
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); | ||
MODULE_ALIAS("platform:nuc900-wdt"); |