s3c2410_wdt.c

#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/platform_device.h>

#include<linux/interrupt.h>

#include <linux/clk.h>

#include <linux/uaccess.h>

#include <linux/io.h>

#include <mach/map.h>

#undef S3C_VA_WATCHDOG

#define S3C_VA_WATCHDOG (0)

#include<plat/regs-watchdog.h>

#define PFX "s3c2410-wdt: "

#define CONFIG_S3C2410_WATCHDOG_ATBOOT (1)

#define CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME (30)

static int nowayout = WATCHDOG_NOWAYOUT;

static int tmr_margin =CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME;

static int tmr_atboot = CONFIG_S3C2410_WATCHDOG_ATBOOT;

static int soft_noboot;

static int debug;

module_param(tmr_margin,  int, 0);

module_param(tmr_atboot,  int, 0);

module_param(nowayout,   int, 0);

module_param(soft_noboot, int, 0);

module_param(debug,  int, 0);

MODULE_PARM_DESC(tmr_margin, "Watchdog tmr_margin in seconds.default="

__MODULE_STRING(CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME)")");

MODULE_PARM_DESC(tmr_atboot,

"Watchdog is started at boot time if set to 1, default="

__MODULE_STRING(CONFIG_S3C2410_WATCHDOG_ATBOOT));

MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped oncestarted (default="

__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

MODULE_PARM_DESC(soft_noboot, "Watchdog action, set to 1 toignore reboots, 0 to reboot (default depends onONLY_TESTING)");

MODULE_PARM_DESC(debug, "Watchdog debug, set to>1 for debug, (default 0)");

typedef enum close_state {

CLOSE_STATE_NOT,

CLOSE_STATE_ALLOW = 0x4021

} close_state_t;

static unsigned long open_lock;

static struct device   *wdt_dev;

static struct resource *wdt_mem;

static struct resource *wdt_irq;

static struct clk *wdt_clock;

static void __iomem *wdt_base;

static unsigned int wdt_count;

static close_state_t allow_close;

static DEFINE_SPINLOCK(wdt_lock);

#define DBG(msg...) do { \

if (debug) \

printk(KERN_INFO msg); \

} while (0)

static void s3c2410wdt_keepalive(void)

{

spin_lock(&wdt_lock);

writel(wdt_count, wdt_base + S3C2410_WTCNT);

spin_unlock(&wdt_lock);

}

static void __s3c2410wdt_stop(void)

{

unsigned long wtcon;

wtcon = readl(wdt_base + S3C2410_WTCON);

wtcon &= ~(S3C2410_WTCON_ENABLE |S3C2410_WTCON_RSTEN);

writel(wtcon, wdt_base + S3C2410_WTCON);

}

static void s3c2410wdt_stop(void)

{

spin_lock(&wdt_lock);

__s3c2410wdt_stop();

spin_unlock(&wdt_lock);

}

static void s3c2410wdt_start(void)

{

unsigned long wtcon;

spin_lock(&wdt_lock);

__s3c2410wdt_stop();

wtcon = readl(wdt_base + S3C2410_WTCON);

wtcon |= S3C2410_WTCON_ENABLE | S3C2410_WTCON_DIV128;

if (soft_noboot) {

wtcon |= S3C2410_WTCON_INTEN;

wtcon &= ~S3C2410_WTCON_RSTEN;

} else {

wtcon &= ~S3C2410_WTCON_INTEN;

wtcon |= S3C2410_WTCON_RSTEN;

}

DBG("%s: wdt_count=0xx, wtcon=lx\n",

   __func__, wdt_count,wtcon);

writel(wdt_count, wdt_base + S3C2410_WTDAT);

writel(wdt_count, wdt_base + S3C2410_WTCNT);

writel(wtcon, wdt_base + S3C2410_WTCON);

spin_unlock(&wdt_lock);

}

static int s3c2410wdt_set_heartbeat(int timeout)

{

unsigned int freq = clk_get_rate(wdt_clock);

unsigned int count;

unsigned int divisor = 1;

unsigned long wtcon;

if (timeout < 1)

return -EINVAL;

freq /= 128;

count = timeout * freq;

DBG("%s: count=%d, timeout=%d, freq=%d\n",

   __func__, count, timeout,freq);

if (count >= 0x10000) {

for (divisor = 1; divisor <= 0x100; divisor++){

if ((count / divisor) < 0x10000)

break;

}

if ((count / divisor) >= 0x10000) {

dev_err(wdt_dev, "timeout %d too big\n", timeout);

return -EINVAL;

}

}

tmr_margin = timeout;

DBG("%s: timeout=%d, divisor=%d, count=%d (x)\n",

   __func__, timeout,divisor, count, count/divisor);

count /= divisor;

wdt_count = count;

wtcon = readl(wdt_base + S3C2410_WTCON);

wtcon &= ~S3C2410_WTCON_PRESCALE_MASK;

wtcon |= S3C2410_WTCON_PRESCALE(divisor-1);

writel(count, wdt_base + S3C2410_WTDAT);

writel(wtcon, wdt_base + S3C2410_WTCON);

return 0;

}

static int s3c2410wdt_open(struct inode *inode, struct file*file)

{

if (test_and_set_bit(0, &open_lock))

return -EBUSY;

if (nowayout)

__module_get(THIS_MODULE);

allow_close = CLOSE_STATE_NOT;

s3c2410wdt_start();

return nonseekable_open(inode, file);

}

static int s3c2410wdt_release(struct inode *inode, struct file*file)

{

if (allow_close == CLOSE_STATE_ALLOW)

s3c2410wdt_stop();

else {

dev_err(wdt_dev, "Unexpected close, not stoppingwatchdog\n");

s3c2410wdt_keepalive();

}

allow_close = CLOSE_STATE_NOT;

clear_bit(0, &open_lock);

return 0;

}

static ssize_t s3c2410wdt_write(struct file *file, const char__user *data,

size_t len, loff_t *ppos)

{

if (len) {

if (!nowayout) {

size_t i;

allow_close = CLOSE_STATE_NOT;

for (i = 0; i != len; i++) {

char c;

if (get_user(c, data + i))

return -EFAULT;

if (c == 'V')

allow_close = CLOSE_STATE_ALLOW;

}

}

s3c2410wdt_keepalive();

}

return len;

}

#define OPTIONS WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |WDIOF_MAGICCLOSE

static const struct watchdog_info s3c2410_wdt_ident = {

.options         =    OPTIONS,

.firmware_version = 0,

.identity        = "S3C2410 Watchdog",

};

static long s3c2410wdt_ioctl(struct file *file, unsigned intcmd,

unsigned long arg)

{

void __user *argp = (void __user *)arg;

int __user *p = argp;

int new_margin;

switch (cmd) {

case WDIOC_GETSUPPORT:

return copy_to_user(argp,&s3c2410_wdt_ident,

sizeof(s3c2410_wdt_ident)) ? -EFAULT : 0;

case WDIOC_GETSTATUS:

case WDIOC_GETBOOTSTATUS:

return put_user(0, p);

case WDIOC_KEEPALIVE:

s3c2410wdt_keepalive();

return 0;

case WDIOC_SETTIMEOUT:

if (get_user(new_margin, p))

return -EFAULT;

if (s3c2410wdt_set_heartbeat(new_margin))

return -EINVAL;

s3c2410wdt_keepalive();

return put_user(tmr_margin, p);

case WDIOC_GETTIMEOUT:

return put_user(tmr_margin, p);

default:

return -ENOTTY;

}

}

static const struct file_operations s3c2410wdt_fops = {

.owner = THIS_MODULE,

.llseek = no_llseek,

.write = s3c2410wdt_write,

.unlocked_ioctl = s3c2410wdt_ioctl,

.open = s3c2410wdt_open,

.release = s3c2410wdt_release,

};

static struct miscdevice s3c2410wdt_miscdev = {

.minor = WATCHDOG_MINOR,

.name = "watchdog",

.fops = &s3c2410wdt_fops,

};

static irqreturn_t s3c2410wdt_irq(int irqno, void*param)

{

dev_info(wdt_dev, "watchdog timer expired (irq)\n");

s3c2410wdt_keepalive();

return IRQ_HANDLED;

}

static int s3c2410wdt_probe(struct platform_device*pdev)

{

struct resource *res;

struct device *dev;

unsigned int wtcon;

int started = 0;

int ret;

int size;

DBG("%s: probe=%p\n", __func__, pdev);

dev = &pdev->dev;

wdt_dev = &pdev->dev;

res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

if (res == NULL) {

dev_err(dev, "no memory resource specified\n");

return -ENOENT;

}

size = (res->end - res->start) +1;

wdt_mem = request_mem_region(res->start, size,pdev->name);

if (wdt_mem == NULL) {

dev_err(dev, "failed to get memory region\n");

ret = -ENOENT;

goto err_req;

}

wdt_base = ioremap(res->start, size);

if (wdt_base == NULL) {

dev_err(dev, "failed to ioremap() region\n");

ret = -EINVAL;

goto err_req;

}

DBG("probe: mapped wdt_base=%p\n", wdt_base);

wdt_irq = platform_get_resource(pdev, IORESOURCE_IRQ,0);

if (wdt_irq == NULL) {

dev_err(dev, "no irq resource specified\n");

ret = -ENOENT;

goto err_map;

}

ret = request_irq(wdt_irq->start,s3c2410wdt_irq, 0, pdev->name, pdev);

if (ret != 0) {

dev_err(dev, "failed to install irq (%d)\n", ret);

goto err_map;

}

wdt_clock = clk_get(&pdev->dev,"watchdog");

if (IS_ERR(wdt_clock)) {

dev_err(dev, "failed to find watchdog clock source\n");

ret = PTR_ERR(wdt_clock);

goto err_irq;

}

clk_enable(wdt_clock);

if (s3c2410wdt_set_heartbeat(tmr_margin)) {

started = s3c2410wdt_set_heartbeat(

CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME);

if (started == 0)

dev_info(dev,

  "tmr_margin value out of range, default %dused\n",

     CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME);

else

dev_info(dev, "default timer value is out of range, cannotstart\n");

}

ret =misc_register(&s3c2410wdt_miscdev);

if (ret) {

dev_err(dev, "cannot register miscdev on minor=%d(%d)\n",

WATCHDOG_MINOR, ret);

goto err_clk;

}

if (tmr_atboot && started ==0) {

dev_info(dev, "starting watchdog timer\n");

s3c2410wdt_start();

} else if (!tmr_atboot) {

s3c2410wdt_stop();

}

wtcon = readl(wdt_base + S3C2410_WTCON);

dev_info(dev, "watchdog %sactive, reset %sabled, irq%sabled\n",

(wtcon & S3C2410_WTCON_ENABLE) ? "" : "in",

(wtcon & S3C2410_WTCON_RSTEN) ? "" :"dis",

(wtcon & S3C2410_WTCON_INTEN) ? "" :"en");

return 0;

 err_clk:

clk_disable(wdt_clock);

clk_put(wdt_clock);

 err_irq:

free_irq(wdt_irq->start, pdev);

 err_map:

iounmap(wdt_base);

 err_req:

release_resource(wdt_mem);

kfree(wdt_mem);

return ret;

}

static int s3c2410wdt_remove(struct platform_device*dev)

{

release_resource(wdt_mem);

kfree(wdt_mem);

wdt_mem = NULL;

free_irq(wdt_irq->start, dev);

wdt_irq = NULL;

clk_disable(wdt_clock);

clk_put(wdt_clock);

wdt_clock = NULL;

iounmap(wdt_base);

misc_deregister(&s3c2410wdt_miscdev);

return 0;

}

static void s3c2410wdt_shutdown(struct platform_device*dev)

{

s3c2410wdt_stop();

}

#ifdef CONFIG_PM

static unsigned long wtcon_save;

static unsigned long wtdat_save;

static int s3c2410wdt_suspend(struct platform_device *dev,pm_message_t state)

{

wtcon_save = readl(wdt_base + S3C2410_WTCON);

wtdat_save = readl(wdt_base + S3C2410_WTDAT);

s3c2410wdt_stop();

return 0;

}

static int s3c2410wdt_resume(struct platform_device*dev)

{

writel(wtdat_save, wdt_base + S3C2410_WTDAT);

writel(wtdat_save, wdt_base + S3C2410_WTCNT);

writel(wtcon_save, wdt_base + S3C2410_WTCON);

printk(KERN_INFO PFX "watchdog %sabled\n",

     (wtcon_save & S3C2410_WTCON_ENABLE) ? "en" :"dis");

return 0;

}

#else

#define s3c2410wdt_suspend NULL

#define s3c2410wdt_resume  NULL

#endif

static struct platform_driver s3c2410wdt_driver = {

.probe = s3c2410wdt_probe,

.remove = s3c2410wdt_remove,

.shutdown = s3c2410wdt_shutdown,

.suspend = s3c2410wdt_suspend,

.resume = s3c2410wdt_resume,

.driver = {

.owner = THIS_MODULE,

.name = "s3c2410-wdt",

},

};

static char banner[] __initdata =

KERN_INFO "S3C2410 Watchdog Timer, (c) 2004 SimtecElectronics\n";

static int __init watchdog_init(void)

{

printk(banner);

returnplatform_driver_register(&s3c2410wdt_driver);

}

static void __exit watchdog_exit(void)

{

platform_driver_unregister(&s3c2410wdt_driver);

}

module_init(watchdog_init);

module_exit(watchdog_exit);

MODULE_AUTHOR("Ben Dooks<[e-mail]>, "

    "Dimitry Andric<[e-mail]>");

MODULE_DESCRIPTION("S3C2410 Watchdog Device Driver");

MODULE_LICENSE("GPL");

MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);

MODULE_ALIAS("platform:s3c2410-wdt");