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Message-ID: <AOUAdwCCDk8v*1Yj0s9Qo4qH.3.1619149686926.Hmail.wangqing@vivo.com>
Date: Fri, 23 Apr 2021 11:48:06 +0800 (GMT+08:00)
From: 王擎 <wangqing@...o.com>
To: Guenter Roeck <linux@...ck-us.net>
Cc: Wim Van Sebroeck <wim@...ux-watchdog.org>,
Rob Herring <robh+dt@...nel.org>,
Matthias Brugger <matthias.bgg@...il.com>,
linux-watchdog@...r.kernel.org, devicetree@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org,
linux-mediatek@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re:Re: [PATCH V7 1/2] watchdog: mtk: support pre-timeout when the bark irq is available
>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@...o.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.
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;
>> +
>> + 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.
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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