Re: [PATCH] watchdog/imx2+: add support for pretimeout interrupt

["Oskar Schirmer" <oskar@scara.com>]

Hi Wim,

On Tue, Jul 03, 2012 at 09:10:08 +0000, Oskar Schirmer wrote:
> This watchdog device provides pretimeout facilities:
> Set some timeout value and get informed about imminent
> watchdog activity thru interrupt.

sent this patch a while ago, as yet unprocessed.
Could You give it an ack?
If not so, please let me know reasons for it, so I can rework it.

thanks a lot,
  Oskar

> Allow user to wait for this interrupt thru poll(2),
> and to clear it thru read(2).
> 
> Signed-off-by: Oskar Schirmer <oskar@scara.com>
> Cc: Wim Van Sebroeck <wim@iguana.be>
> Cc: Wolfram Sang <w.sang@pengutronix.de>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> ---
> Resubmitted as it probably got lost on first attempt (2012/05/31)
> 
>  drivers/watchdog/imx2_wdt.c |  129 ++++++++++++++++++++++++++++++++++++++++++-
>  1 files changed, 128 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/watchdog/imx2_wdt.c b/drivers/watchdog/imx2_wdt.c
> index bcfab2b..09172c8 100644
> --- a/drivers/watchdog/imx2_wdt.c
> +++ b/drivers/watchdog/imx2_wdt.c
> @@ -21,11 +21,16 @@
>   */
>  
>  #include <linux/init.h>
> +#include <linux/interrupt.h>
>  #include <linux/kernel.h>
>  #include <linux/miscdevice.h>
>  #include <linux/module.h>
>  #include <linux/moduleparam.h>
>  #include <linux/platform_device.h>
> +#include <linux/poll.h>
> +#include <linux/sched.h>
> +#include <linux/spinlock.h>
> +#include <linux/wait.h>
>  #include <linux/watchdog.h>
>  #include <linux/clk.h>
>  #include <linux/fs.h>
> @@ -49,6 +54,11 @@
>  #define IMX2_WDT_WRSR		0x04		/* Reset Status Register */
>  #define IMX2_WDT_WRSR_TOUT	(1 << 1)	/* -> Reset due to Timeout */
>  
> +#define IMX2_WDT_WICT		0x06		/* Interrupt Control Reg */
> +#define IMX2_WDT_WICT_WIE	(1 << 15)	/* -> Interrupt Enable */
> +#define IMX2_WDT_WICT_WTIS	(1 << 14)	/* -> Timer Interrupt Status */
> +#define IMX2_WDT_WICT_WICT	(0xFF << 0)	/* -> Interrupt Count Timeout */
> +
>  #define IMX2_WDT_MAX_TIME	128
>  #define IMX2_WDT_DEFAULT_TIME	60		/* in seconds */
>  
> @@ -64,6 +74,11 @@ static struct {
>  	unsigned timeout;
>  	unsigned long status;
>  	struct timer_list timer;	/* Pings the watchdog when closed */
> +	int irq;
> +	spinlock_t read_lock;
> +	wait_queue_head_t read_q;
> +	unsigned char pretimer_once;
> +	unsigned char pretimer_data;
>  } imx2_wdt;
>  
>  static struct miscdevice imx2_wdt_miscdev;
> @@ -81,7 +96,8 @@ MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default="
>  
>  static const struct watchdog_info imx2_wdt_info = {
>  	.identity = "imx2+ watchdog",
> -	.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
> +	.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE |
> +		WDIOF_PRETIMEOUT,
>  };
>  
>  static inline void imx2_wdt_setup(void)
> @@ -148,6 +164,28 @@ static void imx2_wdt_set_timeout(int new_timeout)
>  	__raw_writew(val, imx2_wdt.base + IMX2_WDT_WCR);
>  }
>  
> +static void imx2_wdt_set_pretimeout(int new_pretimeout)
> +{
> +	u16 val = new_pretimeout;
> +
> +	if (val > 0)
> +		val = (val << 1) | IMX2_WDT_WICT_WIE;
> +	__raw_writew(val, imx2_wdt.base + IMX2_WDT_WICT);
> +}
> +
> +static void imx2_wdt_interrupt(int irq, void *dev_id)
> +{
> +	u16 val;
> +	spin_lock(&imx2_wdt.read_lock);
> +	val = __raw_readw(imx2_wdt.base + IMX2_WDT_WICT);
> +	if (val & IMX2_WDT_WICT_WTIS) {
> +		__raw_writew(val, imx2_wdt.base + IMX2_WDT_WICT);
> +		imx2_wdt.pretimer_data = 1;
> +	}
> +	wake_up_interruptible(&imx2_wdt.read_q);
> +	spin_unlock(&imx2_wdt.read_lock);
> +}
> +
>  static int imx2_wdt_open(struct inode *inode, struct file *file)
>  {
>  	if (test_and_set_bit(IMX2_WDT_STATUS_OPEN, &imx2_wdt.status))
> @@ -210,6 +248,26 @@ static long imx2_wdt_ioctl(struct file *file, unsigned int cmd,
>  	case WDIOC_GETTIMEOUT:
>  		return put_user(imx2_wdt.timeout, p);
>  
> +	case WDIOC_SETPRETIMEOUT:
> +		if (get_user(new_value, p))
> +			return -EFAULT;
> +		if ((new_value < 0) || (new_value >= IMX2_WDT_MAX_TIME))
> +			return -EINVAL;
> +		if (imx2_wdt.irq < 0)
> +			return -EINVAL;
> +		if (imx2_wdt.pretimer_once)
> +			return -EPERM;
> +		imx2_wdt.pretimer_once = 1;
> +		imx2_wdt_set_pretimeout(new_value);
> +
> +	case WDIOC_GETPRETIMEOUT:
> +		val = __raw_readw(imx2_wdt.base + IMX2_WDT_WICT);
> +		if (val & IMX2_WDT_WICT_WIE)
> +			val = (val & IMX2_WDT_WICT_WICT) >> 1;
> +		else
> +			val = 0;
> +		return put_user(val, p);
> +
>  	default:
>  		return -ENOTTY;
>  	}
> @@ -237,6 +295,59 @@ static ssize_t imx2_wdt_write(struct file *file, const char __user *data,
>  	return len;
>  }
>  
> +static ssize_t imx2_wdt_read(struct file *file, char __user *data,
> +				size_t count, loff_t *ppos)
> +{
> +	wait_queue_t wait;
> +	unsigned long flags;
> +
> +	if (count <= 0)
> +		return 0;
> +
> +	spin_lock_irqsave(&imx2_wdt.read_lock, flags);
> +	while (!imx2_wdt.pretimer_data) {
> +		if (file->f_flags & O_NONBLOCK) {
> +			spin_unlock_irqrestore(&imx2_wdt.read_lock, flags);
> +			return -EAGAIN;
> +		}
> +
> +		init_waitqueue_entry(&wait, current);
> +		add_wait_queue(&imx2_wdt.read_q, &wait);
> +		set_current_state(TASK_INTERRUPTIBLE);
> +		spin_unlock_irqrestore(&imx2_wdt.read_lock, flags);
> +		schedule();
> +		spin_lock_irqsave(&imx2_wdt.read_lock, flags);
> +		remove_wait_queue(&imx2_wdt.read_q, &wait);
> +
> +		if (signal_pending(current)) {
> +			spin_unlock_irqrestore(&imx2_wdt.read_lock, flags);
> +			return -ERESTARTSYS;
> +		}
> +	}
> +
> +	imx2_wdt.pretimer_data = 0;
> +	spin_unlock_irqrestore(&imx2_wdt.read_lock, flags);
> +	if (copy_to_user(data, &imx2_wdt.pretimer_data, 1))
> +		return -EFAULT;
> +
> +	return 1;
> +}
> +
> +static unsigned int imx2_wdt_poll(struct file *file, poll_table *wait)
> +{
> +	unsigned int mask = 0;
> +	unsigned long flags;
> +
> +	poll_wait(file, &imx2_wdt.read_q, wait);
> +
> +	spin_lock_irqsave(&imx2_wdt.read_lock, flags);
> +	if (imx2_wdt.pretimer_data)
> +		mask |= POLLIN | POLLRDNORM;
> +	spin_unlock_irqrestore(&imx2_wdt.read_lock, flags);
> +
> +	return mask;
> +}
> +
>  static const struct file_operations imx2_wdt_fops = {
>  	.owner = THIS_MODULE,
>  	.llseek = no_llseek,
> @@ -244,6 +355,8 @@ static const struct file_operations imx2_wdt_fops = {
>  	.open = imx2_wdt_open,
>  	.release = imx2_wdt_close,
>  	.write = imx2_wdt_write,
> +	.read = imx2_wdt_read,
> +	.poll = imx2_wdt_poll,
>  };
>  
>  static struct miscdevice imx2_wdt_miscdev = {
> @@ -282,6 +395,16 @@ static int __init imx2_wdt_probe(struct platform_device *pdev)
>  
>  	setup_timer(&imx2_wdt.timer, imx2_wdt_timer_ping, 0);
>  
> +	init_waitqueue_head(&imx2_wdt.read_q);
> +	spin_lock_init(&imx2_wdt.read_lock);
> +	imx2_wdt.irq = platform_get_irq(pdev, 0);
> +	if (imx2_wdt.irq >= 0) {
> +		ret = request_irq(imx2_wdt.irq, imx2_wdt_interrupt,
> +					0, "watchdog", pdev);
> +		if (ret)
> +			goto fail;
> +	}
> +
>  	imx2_wdt_miscdev.parent = &pdev->dev;
>  	ret = misc_register(&imx2_wdt_miscdev);
>  	if (ret)
> @@ -294,6 +417,8 @@ static int __init imx2_wdt_probe(struct platform_device *pdev)
>  
>  fail:
>  	imx2_wdt_miscdev.parent = NULL;
> +	if (imx2_wdt.irq >= 0)
> +		free_irq(imx2_wdt.irq, pdev);
>  	clk_put(imx2_wdt.clk);
>  	return ret;
>  }
> @@ -301,6 +426,8 @@ fail:
>  static int __exit imx2_wdt_remove(struct platform_device *pdev)
>  {
>  	misc_deregister(&imx2_wdt_miscdev);
> +	if (imx2_wdt.irq >= 0)
> +		free_irq(imx2_wdt.irq, pdev);
>  
>  	if (test_bit(IMX2_WDT_STATUS_STARTED, &imx2_wdt.status)) {
>  		del_timer_sync(&imx2_wdt.timer);
> -- 
> 1.7.5.4
> 
> 
> 

-- 
oskar schirmer
calsowstr 22 / 37085 göttingen / germany
tel +49 551 5315924
fax +49 551 5315925
mailto:oskar@scara.com, http://scara.com/~schirmer/o