On 4/14/21 12:28 AM, Wang Qing wrote:
> Use the bark interrupt as the pretimeout notifier if available.
>
> By default, the pretimeout notification shall occur one second earlier
> than the timeout.
>
> V2:
> - panic() by default if WATCHDOG_PRETIMEOUT_GOV is not enabled
>
> Signed-off-by: Wang Qing <wangqing@xxxxxxxx>
> ---
> drivers/watchdog/mtk_wdt.c | 57 ++++++++++++++++++++++++++++++++++++++++++----
> 1 file changed, 52 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/watchdog/mtk_wdt.c b/drivers/watchdog/mtk_wdt.c
> index 97ca993..b0ec933
> --- 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
> @@ -234,18 +235,41 @@ static int mtk_wdt_start(struct watchdog_device *wdt_dev)
> void __iomem *wdt_base = mtk_wdt->wdt_base;
> int ret;
>
> - ret = mtk_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
> + ret = mtk_wdt_set_timeout(wdt_dev, wdt_dev->timeout - wdt_dev->pretimeout);
> if (ret < 0)
> return ret;
>
> reg = ioread32(wdt_base + WDT_MODE);
> - reg &= ~(WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN);
> + reg &= ~WDT_MODE_IRQ_EN;
> + if (wdt_dev->pretimeout)
> + reg |= WDT_MODE_IRQ_EN;
> + else
> + reg &= ~WDT_MODE_IRQ_EN;
> reg |= (WDT_MODE_EN | WDT_MODE_KEY);
> iowrite32(reg, wdt_base + WDT_MODE);
>
You said previously that the pretimeout would prevent the real timeout / reset
from happening, and the driver has no provision to set the real timeout.
That makes this a no-go.
> return 0;
> }
>
> +static int mtk_wdt_set_pretimeout(struct watchdog_device *wdd,
> + unsigned int timeout)
> +{
> + wdd->pretimeout = timeout;
> + return mtk_wdt_start(wdd);
> +}
> +
> +static irqreturn_t mtk_wdt_isr(int irq, void *arg)
> +{
> + struct watchdog_device *wdd = arg;
> +if (IS_ENABLED(CONFIG_WATCHDOG_PRETIMEOUT_GOV))
> + watchdog_notify_pretimeout(wdd);
> +else
> + //panic by decault instead of WDT_SWRST;
> + panic("MTk Watchdog bark!\n");
> +
The idea behind the pretimeout governor is that it can be disabled
by setting it to "none", and if pretimeout governors are disabled
it is supposed to be a no-op. The above bypasses this mechanism
and is not acceptable.
This suggests that the real timeout indeed doesn't happen when
WDT_MODE_IRQ_EN is set. Again, this is unacceptable.
On a side note, formatting is way off here.
Guenter
> + return IRQ_HANDLED;
> +}
> +
> static const struct watchdog_info mtk_wdt_info = {
> .identity = DRV_NAME,
> .options = WDIOF_SETTIMEOUT |
> @@ -253,12 +277,21 @@ 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 +300,7 @@ 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 +312,22 @@ 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 = 1;
> + } 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;
> @@ -360,7 +408,6 @@ static struct platform_driver mtk_wdt_driver = {
> };
>
> module_platform_driver(mtk_wdt_driver);
> -
> module_param(timeout, uint, 0);
> MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds");
>
>
