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Message-ID: <20190910180655.GA25286@roeck-us.net>
Date: Tue, 10 Sep 2019 11:06:55 -0700
From: Guenter Roeck <linux@...ck-us.net>
To: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@...aro.org>
Cc: bjorn.andersson@...aro.org, wim@...ux-watchdog.org,
agross@...nel.org, linux-arm-msm@...r.kernel.org,
linux-watchdog@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] watchdog: qcom: support pre-timeout when the bark
irq is available
On Fri, Sep 06, 2019 at 10:54:10PM +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>
Nitpick below, otherwise:
Reviewed-by: Guenter Roeck <linux@...ck-us.net>
> ---
> drivers/watchdog/qcom-wdt.c | 70 ++++++++++++++++++++++++++++++++++---
> 1 file changed, 65 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/watchdog/qcom-wdt.c b/drivers/watchdog/qcom-wdt.c
> index 7be7f87be28f..935c78a882a3 100644
> --- a/drivers/watchdog/qcom-wdt.c
> +++ b/drivers/watchdog/qcom-wdt.c
> @@ -1,8 +1,10 @@
> // SPDX-License-Identifier: GPL-2.0-only
> /* Copyright (c) 2014, The Linux Foundation. All rights reserved.
> */
> +#include <linux/bits.h>
> #include <linux/clk.h>
> #include <linux/delay.h>
> +#include <linux/interrupt.h>
> #include <linux/io.h>
> #include <linux/kernel.h>
> #include <linux/module.h>
> @@ -19,6 +21,9 @@ enum wdt_reg {
> WDT_BITE_TIME,
> };
>
> +#define QCOM_WDT_ENABLE BIT(0)
> +#define QCOM_WDT_ENABLE_IRQ BIT(1)
> +
> static const u32 reg_offset_data_apcs_tmr[] = {
> [WDT_RST] = 0x38,
> [WDT_EN] = 0x40,
> @@ -54,15 +59,35 @@ 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->pretimeout)
> + enable |= QCOM_WDT_ENABLE_IRQ;
> +
> + 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 - wdd->pretimeout;
>
> 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 +114,13 @@ 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 +137,7 @@ 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_WDT_ENABLE, wdt_addr(wdt, WDT_EN));
>
> /*
> * Actually make sure the above sequence hits hardware before sleeping.
> @@ -121,6 +153,7 @@ 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 +166,15 @@ 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 +188,7 @@ 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 +246,25 @@ static int qcom_wdt_probe(struct platform_device *pdev)
> return -EINVAL;
> }
>
> - wdt->wdd.info = &qcom_wdt_info;
> + /* check if there is pretimeout support */
> + irq = platform_get_irq(pdev, 0);
> + if (irq > 0) {
> + ret = devm_request_irq(dev, irq, qcom_wdt_isr,
> + IRQF_TRIGGER_RISING,
> + "wdt_bark", &wdt->wdd);
> + if (ret)
> + return ret;
> +
> + wdt->wdd.info = &qcom_wdt_pt_info;
> + wdt->wdd.pretimeout = 1;
> + } else {
> + if (irq == -EPROBE_DEFER)
> + return -EPROBE_DEFER;
> +
> + wdt->wdd.info = &qcom_wdt_info;
> + wdt->wdd.pretimeout = 0;
It is not necessary to set pretimeout to 0; the data structure was
allocated with devm_kzalloc(). The compiler won't know that and
generate unnecessary code otherwise.
> + }
> +
> wdt->wdd.ops = &qcom_wdt_ops;
> wdt->wdd.min_timeout = 1;
> wdt->wdd.max_timeout = 0x10000000U / wdt->rate;
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