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([2600:1700:e321:62f0:329c:23ff:fee3:9d7c]) by smtp.gmail.com with ESMTPSA id f4-20020a170902ce8400b0016cd74dae66sm8748344plg.28.2022.08.08.04.58.57 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 08 Aug 2022 04:58:58 -0700 (PDT) Sender: Guenter Roeck Message-ID: <7ab495dd-4b3e-46e8-6db0-1dd20860043f@roeck-us.net> Date: Mon, 8 Aug 2022 04:58:56 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.11.0 Subject: Re: [PATCH v2] watchdog: meson: keep running if already active Content-Language: en-US To: Philippe Boos , Wim Van Sebroeck , Neil Armstrong Cc: Kevin Hilman , Jerome Brunet , Martin Blumenstingl , "open list:WATCHDOG DEVICE DRIVERS" , "moderated list:ARM/Amlogic Meson SoC support" , "open list:ARM/Amlogic Meson SoC support" , open list References: <20220801092150.4449-1-pboos@baylibre.com> From: Guenter Roeck In-Reply-To: <20220801092150.4449-1-pboos@baylibre.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-watchdog@vger.kernel.org On 8/1/22 02:21, Philippe Boos wrote: > If the watchdog is already running (e.g.: started by bootloader) then > the kernel driver should keep the watchdog active but the amlogic driver > turns it off. > > Let the driver fix the clock rate if already active because we do not > know the previous timebase value. To avoid unintentional resetting we > temporarily set it to its maximum value. > > Then keep the enable bit if is was previously active. > > Signed-off-by: Philippe Boos What changed since v1 ? Guenter > --- > drivers/watchdog/meson_gxbb_wdt.c | 24 +++++++++++++++++++----- > 1 file changed, 19 insertions(+), 5 deletions(-) > > diff --git a/drivers/watchdog/meson_gxbb_wdt.c b/drivers/watchdog/meson_gxbb_wdt.c > index 5a9ca10fbcfa..8be8fd9e5637 100644 > --- a/drivers/watchdog/meson_gxbb_wdt.c > +++ b/drivers/watchdog/meson_gxbb_wdt.c > @@ -146,6 +146,7 @@ static int meson_gxbb_wdt_probe(struct platform_device *pdev) > struct device *dev = &pdev->dev; > struct meson_gxbb_wdt *data; > int ret; > + u32 ctrl_reg; > > data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); > if (!data) > @@ -177,13 +178,26 @@ static int meson_gxbb_wdt_probe(struct platform_device *pdev) > data->wdt_dev.timeout = DEFAULT_TIMEOUT; > watchdog_set_drvdata(&data->wdt_dev, data); > > + ctrl_reg = readl(data->reg_base + GXBB_WDT_CTRL_REG) & > + GXBB_WDT_CTRL_EN; > + > + if (ctrl_reg) { > + /* Watchdog is running - keep it running but extend timeout > + * to the maximum while setting the timebase > + */ > + set_bit(WDOG_HW_RUNNING, &data->wdt_dev.status); > + meson_gxbb_wdt_set_timeout(&data->wdt_dev, > + GXBB_WDT_TCNT_SETUP_MASK / 1000); > + } > + > /* Setup with 1ms timebase */ > - writel(((clk_get_rate(data->clk) / 1000) & GXBB_WDT_CTRL_DIV_MASK) | > - GXBB_WDT_CTRL_EE_RESET | > - GXBB_WDT_CTRL_CLK_EN | > - GXBB_WDT_CTRL_CLKDIV_EN, > - data->reg_base + GXBB_WDT_CTRL_REG); > + ctrl_reg |= ((clk_get_rate(data->clk) / 1000) & > + GXBB_WDT_CTRL_DIV_MASK) | > + GXBB_WDT_CTRL_EE_RESET | > + GXBB_WDT_CTRL_CLK_EN | > + GXBB_WDT_CTRL_CLKDIV_EN; > > + writel(ctrl_reg, data->reg_base + GXBB_WDT_CTRL_REG); > meson_gxbb_wdt_set_timeout(&data->wdt_dev, data->wdt_dev.timeout); > > watchdog_stop_on_reboot(&data->wdt_dev);