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Message-ID: <20120905072313.GA18848@curry>
Date: 5 Sep 2012 07:23:13 +0000
From: "Oskar Schirmer" <oskar@...ra.com>
To: "Wim Van Sebroeck" <wim@...ana.be>
Cc: linux-kernel@...r.kernel.org,
"Wolfram Sang" <w.sang@...gutronix.de>,
" Andrew Morton" <akpm@...ux-foundation.org>
Subject: Re: [PATCH] watchdog/imx2+: add support for pretimeout interrupt
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@...ra.com>
> Cc: Wim Van Sebroeck <wim@...ana.be>
> Cc: Wolfram Sang <w.sang@...gutronix.de>
> Cc: Andrew Morton <akpm@...ux-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@...ra.com, http://scara.com/~schirmer/o
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