[PATCH V7 1/2] watchdog: mtk: support pre-timeout when the bark irq is available
Guenter Roeck
linux at roeck-us.net
Fri Apr 23 15:10:48 BST 2021
On Fri, Apr 23, 2021 at 03:12:24PM +0800, 王擎 wrote:
>
> >On 4/22/21 8:48 PM, 王擎 wrote:
> >>
> >>> On 4/22/21 7:53 PM, Wang Qing wrote:
> >>>> Use the bark interrupt as the pretimeout notifier if available.
> >>>>
> >>>> When the watchdog timer expires in dual mode, an interrupt will be
> >>>> triggered first, then the timing restarts. The reset signal will be
> >>>> initiated when the timer expires again.
> >>>>
> >>>> The pretimeout notification shall occur at timeout-sec/2.
> >>>>
> >>>> V2:
> >>>> - panic() by default if WATCHDOG_PRETIMEOUT_GOV is not enabled.
> >>>>
> >>>> V3:
> >>>> - Modify the pretimeout behavior, manually reset after the pretimeout
> >>>> - is processed and wait until timeout.
> >>>>
> >>>> V4:
> >>>> - Remove pretimeout related processing.
> >>>> - Add dual mode control separately.
> >>>>
> >>>> V5:
> >>>> - Fix some formatting and printing problems.
> >>>>
> >>>> V6:
> >>>> - Realize pretimeout processing through dualmode.
> >>>>
> >>>> V7:
> >>>> - Add set_pretimeout().
> >>>>
> >>>> Signed-off-by: Wang Qing <wangqing at vivo.com>
> >>>> ---
> >>>> drivers/watchdog/mtk_wdt.c | 76 +++++++++++++++++++++++++++++++++++++++++++---
> >>>> 1 file changed, 71 insertions(+), 5 deletions(-)
> >>>>
> >>>> diff --git a/drivers/watchdog/mtk_wdt.c b/drivers/watchdog/mtk_wdt.c
> >>>> index 97ca993..ab3ac5d
> >>>> --- a/drivers/watchdog/mtk_wdt.c
> >>>> +++ b/drivers/watchdog/mtk_wdt.c
> >>>> @@ -25,6 +25,7 @@
> >>>> #include <linux/reset-controller.h>
> >>>> #include <linux/types.h>
> >>>> #include <linux/watchdog.h>
> >>>> +#include <linux/interrupt.h>
> >>>>
> >>>> #define WDT_MAX_TIMEOUT 31
> >>>> #define WDT_MIN_TIMEOUT 1
> >>>> @@ -184,15 +185,23 @@ static int mtk_wdt_set_timeout(struct watchdog_device *wdt_dev,
> >>>> {
> >>>> struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
> >>>> void __iomem *wdt_base = mtk_wdt->wdt_base;
> >>>> + unsigned int timeout_interval = timeout;
> >>>> u32 reg;
> >>>>
> >>>> wdt_dev->timeout = timeout;
> >>>> -
> >>>> + /*
> >>>> + * In dual mode, irq will be triggered at timeout / 2
> >>>> + * the real timeout occurs at timeout
> >>>> + */
> >>>> + if (wdt_dev->pretimeout) {
> >>>> + wdt_dev->pretimeout = timeout / 2;
> >>>
> >>> min_timeout is set to 1. I don't this works well if timeout == 1.
> >>> You'll either need to set min_timeout to 2, or handle that case.
> >>
> >> It is appropriate to change min_timeout to 2.
> >>
> >>>
> >>>> + timeout_interval = wdt_dev->pretimeout;
> >>>
> >>> timeout_interval is unnecessary. Just update timeout accordingly.
> >>> It needs to take the situation of timeout == 1 into account, though.
>
> I plan to remove timeout_interval and directly use (timeout-pretimeout)
> update timeout.
>
> >>
> >> timeout represents the reset time. When the user calls timeout_show,
> >> He hopes to get the configured timeout, not the value changed
> >> by pre-timeout.
> >> I modify it like this more in line with the original intention.
> >>
> >>>
> >>>> + }
> >>>> /*
> >>>> * One bit is the value of 512 ticks
> >>>> * The clock has 32 KHz
> >>>> */
> >>>> - reg = WDT_LENGTH_TIMEOUT(timeout << 6) | WDT_LENGTH_KEY;
> >>>> + reg = WDT_LENGTH_TIMEOUT(timeout_interval << 6) | WDT_LENGTH_KEY;
> >>>> iowrite32(reg, wdt_base + WDT_LENGTH);
> >>>>
> >>>> mtk_wdt_ping(wdt_dev);
> >>>> @@ -239,13 +248,46 @@ static int mtk_wdt_start(struct watchdog_device *wdt_dev)
> >>>> return ret;
> >>>>
> >>>> reg = ioread32(wdt_base + WDT_MODE);
> >>>> - reg &= ~(WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN);
> >>>> + if (wdt_dev->pretimeout)
> >>>> + reg |= (WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN);
> >>>> + else
> >>>> + reg &= ~(WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN);
> >>>> reg |= (WDT_MODE_EN | WDT_MODE_KEY);
> >>>> iowrite32(reg, wdt_base + WDT_MODE);
> >>>>
> >>>> return 0;
> >>>> }
> >>>>
> >>>> +static int mtk_wdt_set_pretimeout(struct watchdog_device *wdd,
> >>>> + unsigned int timeout)
> >>>> +{
> >>>> + struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdd);
> >>>> + void __iomem *wdt_base = mtk_wdt->wdt_base;
> >>>> + u32 reg = ioread32(wdt_base + WDT_MODE);
> >>>> +
> >>>> + if (timeout && !wdd->pretimeout) {
> >>>> + wdd->pretimeout = wdd->timeout / 2;
> >>>> + reg |= (WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN);
> >>>> + } else if (!timeout && wdd->pretimeout) {
> >>>> + wdd->pretimeout = 0;
> >>>> + reg &= ~(WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN);
> >>>> + } else
> >>>> + return 0;
Please run your patch through checkpatch; the above results
in a note about a missing { }.
> >>>> +
> >>>> + iowrite32(reg, wdt_base + WDT_MODE);
> >>>
> >>> What is the point of setting the mode here ? It will
> >>> be set again in mtk_wdt_set_timeout(). Seems to me all
> >>> you need to do here is to set wdd->pretimeout,
> >>> then call mtk_wdt_set_timeout().
> >>
> >> mtk_wdt_set_timeout() only set timeout and ping().
> >> Here also need to config to the dualmode or not.
> >>
> >Ah, you are correct. Sorry, I confused this with the start function.
> >That makes me wonder if it would be better to extract a separate
> >function, mtk_wdt_set_mode(), for that purpose. Thoughts ?
>
> I have done this, but I found there is no good abstract method,
> because wdt mode is used in combination, for example：
> WDT_MODE_EN is included in start(), and here is not.
> And the judgment of pretimeout here is also different.
>
Ok, makes sense. Another minor comment above, though.
Thanks,
Guenter
> Thanks,
> Qing
>
> >
> >Thanks,
> >Guenter
> >
> >> Thanks,
> >> Qing
> >>>
> >>> Guenter
> >>>
> >>>> +
> >>>> + return mtk_wdt_set_timeout(wdd, wdd->timeout);
> >>>> +}
> >>>> +
> >>>> +static irqreturn_t mtk_wdt_isr(int irq, void *arg)
> >>>> +{
> >>>> + struct watchdog_device *wdd = arg;
> >>>> +
> >>>> + watchdog_notify_pretimeout(wdd);
> >>>> +
> >>>> + return IRQ_HANDLED;
> >>>> +}
> >>>> +
> >>>> static const struct watchdog_info mtk_wdt_info = {
> >>>> .identity = DRV_NAME,
> >>>> .options = WDIOF_SETTIMEOUT |
> >>>> @@ -253,12 +295,21 @@ static const struct watchdog_info mtk_wdt_info = {
> >>>> WDIOF_MAGICCLOSE,
> >>>> };
> >>>>
> >>>> +static const struct watchdog_info mtk_wdt_pt_info = {
> >>>> + .identity = DRV_NAME,
> >>>> + .options = WDIOF_SETTIMEOUT |
> >>>> + WDIOF_PRETIMEOUT |
> >>>> + WDIOF_KEEPALIVEPING |
> >>>> + WDIOF_MAGICCLOSE,
> >>>> +};
> >>>> +
> >>>> static const struct watchdog_ops mtk_wdt_ops = {
> >>>> .owner = THIS_MODULE,
> >>>> .start = mtk_wdt_start,
> >>>> .stop = mtk_wdt_stop,
> >>>> .ping = mtk_wdt_ping,
> >>>> .set_timeout = mtk_wdt_set_timeout,
> >>>> + .set_pretimeout = mtk_wdt_set_pretimeout,
> >>>> .restart = mtk_wdt_restart,
> >>>> };
> >>>>
> >>>> @@ -267,7 +318,7 @@ static int mtk_wdt_probe(struct platform_device *pdev)
> >>>> struct device *dev = &pdev->dev;
> >>>> struct mtk_wdt_dev *mtk_wdt;
> >>>> const struct mtk_wdt_data *wdt_data;
> >>>> - int err;
> >>>> + int err, irq;
> >>>>
> >>>> mtk_wdt = devm_kzalloc(dev, sizeof(*mtk_wdt), GFP_KERNEL);
> >>>> if (!mtk_wdt)
> >>>> @@ -279,7 +330,22 @@ static int mtk_wdt_probe(struct platform_device *pdev)
> >>>> if (IS_ERR(mtk_wdt->wdt_base))
> >>>> return PTR_ERR(mtk_wdt->wdt_base);
> >>>>
> >>>> - mtk_wdt->wdt_dev.info = &mtk_wdt_info;
> >>>> + irq = platform_get_irq(pdev, 0);
> >>>> + if (irq > 0) {
> >>>> + err = devm_request_irq(&pdev->dev, irq, mtk_wdt_isr, 0, "wdt_bark",
> >>>> + &mtk_wdt->wdt_dev);
> >>>> + if (err)
> >>>> + return err;
> >>>> +
> >>>> + mtk_wdt->wdt_dev.info = &mtk_wdt_pt_info;
> >>>> + mtk_wdt->wdt_dev.pretimeout = WDT_MAX_TIMEOUT / 2;
> >>>> + } else {
> >>>> + if (irq == -EPROBE_DEFER)
> >>>> + return -EPROBE_DEFER;
> >>>> +
> >>>> + mtk_wdt->wdt_dev.info = &mtk_wdt_info;
> >>>> + }
> >>>> +
> >>>> mtk_wdt->wdt_dev.ops = &mtk_wdt_ops;
> >>>> mtk_wdt->wdt_dev.timeout = WDT_MAX_TIMEOUT;
> >>>> mtk_wdt->wdt_dev.max_hw_heartbeat_ms = WDT_MAX_TIMEOUT * 1000;
> >>>>
> >>>
> >>
> >>
> >
>
>
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