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Message-ID: <20190905211913.GA31094@roeck-us.net>
Date: Thu, 5 Sep 2019 14:19:13 -0700
From: Guenter Roeck <linux@...ck-us.net>
To: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@...aro.org>
Cc: agross@...nel.org, wim@...ux-watchdog.org,
bjorn.andersson@...aro.org, linux-arm-msm@...r.kernel.org,
linux-watchdog@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4] watchdog: qcom: support pre-timeout when the bark irq
is available
On Thu, Sep 05, 2019 at 11:00:35PM +0200, Jorge Ramirez-Ortiz wrote:
> Use the bark interrupt as the pre-timeout notifier whenever this
> interrupt is available.
>
> By default, the pretimeout notification shall occur one second earlier
> than the timeout.
>
> Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@...aro.org>
> ---
> v4:
> address Guenter Roeck comments as follows:
> remove unnecessary include and private variable
> provide macro for WDT EN register values
> use pretimeout as per its API intent
> handle EPROBE_DEFER on get_irq
> also:
> handle the irq registration as done in pm8916_wdt.c
> v3:
> remove unnecesary variable added to private.
>
> v2:
> register the pre-timeout notifier instead.
>
> v1:
> drivers/watchdog/qcom-wdt.c | 64 ++++++++++++++++++++++++++++++++++---
> 1 file changed, 59 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/watchdog/qcom-wdt.c b/drivers/watchdog/qcom-wdt.c
> index 7be7f87be28f..0f1d29eeb81d 100644
> --- a/drivers/watchdog/qcom-wdt.c
> +++ b/drivers/watchdog/qcom-wdt.c
> @@ -10,6 +10,7 @@
> #include <linux/platform_device.h>
> #include <linux/watchdog.h>
> #include <linux/of_device.h>
> +#include <linux/interrupt.h>
>
> enum wdt_reg {
> WDT_RST,
> @@ -19,6 +20,9 @@ enum wdt_reg {
> WDT_BITE_TIME,
> };
>
> +#define QCOM_WDT_ENABLE BIT(0)
> +#define QCOM_WDT_ENABLE_IRQ BIT(1)
> +
Using BIT() requires "#include <linux/bits.h>".
> static const u32 reg_offset_data_apcs_tmr[] = {
> [WDT_RST] = 0x38,
> [WDT_EN] = 0x40,
> @@ -54,15 +58,38 @@ struct qcom_wdt *to_qcom_wdt(struct watchdog_device *wdd)
> return container_of(wdd, struct qcom_wdt, wdd);
> }
>
> +static inline int qcom_get_enable(struct watchdog_device *wdd)
> +{
> + int enable = QCOM_WDT_ENABLE;
> +
> + if (wdd->info->options & WDIOF_PRETIMEOUT)
> + enable |= QCOM_WDT_ENABLE_IRQ;
> +
Again, the condition needs to be that pretimeout != 0,
not that it is supported.
> + return enable;
> +}
> +
> +static irqreturn_t qcom_wdt_isr(int irq, void *arg)
> +{
> + struct watchdog_device *wdd = arg;
> +
> + watchdog_notify_pretimeout(wdd);
> +
> + return IRQ_HANDLED;
> +}
> +
> static int qcom_wdt_start(struct watchdog_device *wdd)
> {
> struct qcom_wdt *wdt = to_qcom_wdt(wdd);
> + unsigned int bark = wdd->timeout;
> +
> + if (wdd->pretimeout)
> + bark = bark - wdd->pretimeout;
The if() just adds code and doesn't otherwise do any good.
>
> writel(0, wdt_addr(wdt, WDT_EN));
> writel(1, wdt_addr(wdt, WDT_RST));
> - writel(wdd->timeout * wdt->rate, wdt_addr(wdt, WDT_BARK_TIME));
> + writel(bark * wdt->rate, wdt_addr(wdt, WDT_BARK_TIME));
> writel(wdd->timeout * wdt->rate, wdt_addr(wdt, WDT_BITE_TIME));
> - writel(1, wdt_addr(wdt, WDT_EN));
> + writel(qcom_get_enable(wdd), wdt_addr(wdt, WDT_EN));
> return 0;
> }
>
> @@ -89,6 +116,13 @@ static int qcom_wdt_set_timeout(struct watchdog_device *wdd,
> return qcom_wdt_start(wdd);
> }
>
> +static int qcom_wdt_set_pretimeout(struct watchdog_device *wdd,
> + unsigned int timeout)
> +{
> + wdd->pretimeout = timeout;
> + return qcom_wdt_start(wdd);
> +}
> +
> static int qcom_wdt_restart(struct watchdog_device *wdd, unsigned long action,
> void *data)
> {
> @@ -105,7 +139,7 @@ static int qcom_wdt_restart(struct watchdog_device *wdd, unsigned long action,
> writel(1, wdt_addr(wdt, WDT_RST));
> writel(timeout, wdt_addr(wdt, WDT_BARK_TIME));
> writel(timeout, wdt_addr(wdt, WDT_BITE_TIME));
> - writel(1, wdt_addr(wdt, WDT_EN));
> + writel(qcom_get_enable(wdd), wdt_addr(wdt, WDT_EN));
>
> /*
> * Actually make sure the above sequence hits hardware before sleeping.
> @@ -121,6 +155,7 @@ static const struct watchdog_ops qcom_wdt_ops = {
> .stop = qcom_wdt_stop,
> .ping = qcom_wdt_ping,
> .set_timeout = qcom_wdt_set_timeout,
> + .set_pretimeout = qcom_wdt_set_pretimeout,
> .restart = qcom_wdt_restart,
> .owner = THIS_MODULE,
> };
> @@ -133,6 +168,15 @@ static const struct watchdog_info qcom_wdt_info = {
> .identity = KBUILD_MODNAME,
> };
>
> +static const struct watchdog_info qcom_wdt_pt_info = {
> + .options = WDIOF_KEEPALIVEPING
> + | WDIOF_MAGICCLOSE
> + | WDIOF_SETTIMEOUT
> + | WDIOF_PRETIMEOUT
> + | WDIOF_CARDRESET,
> + .identity = KBUILD_MODNAME,
> +};
> +
> static void qcom_clk_disable_unprepare(void *data)
> {
> clk_disable_unprepare(data);
> @@ -146,7 +190,7 @@ static int qcom_wdt_probe(struct platform_device *pdev)
> struct device_node *np = dev->of_node;
> const u32 *regs;
> u32 percpu_offset;
> - int ret;
> + int irq, ret;
>
> regs = of_device_get_match_data(dev);
> if (!regs) {
> @@ -204,7 +248,17 @@ static int qcom_wdt_probe(struct platform_device *pdev)
> return -EINVAL;
> }
>
> - wdt->wdd.info = &qcom_wdt_info;
> + irq = platform_get_irq(pdev, 0);
> + if (irq > 0) {
> + if (devm_request_irq(dev, irq, qcom_wdt_isr,
> + IRQF_TRIGGER_RISING, "wdt_bark",
> + &wdt->wdd))
> + irq = 0;
> + } else if (irq == -EPROBE_DEFER)
> + return -EPROBE_DEFER;
> +
> + wdt->wdd.info = irq > 0 ? &qcom_wdt_pt_info : &qcom_wdt_info;
> + wdt->wdd.pretimeout = irq > 0 ? 1 : 0;
Why repeat the conditional ? It seems to me that something like
wdt->wdd.info = &qcom_wdt_info;
...
if (irq > 0) {
wdt->wdd.info = &qcom_wdt_pt_info;
wdt->wdd.pretimeout = 1;
...
}
would be much easier and avoid the repeated conditionals.
> wdt->wdd.ops = &qcom_wdt_ops;
> wdt->wdd.min_timeout = 1;
> wdt->wdd.max_timeout = 0x10000000U / wdt->rate;
> --
> 2.23.0
>
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