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Fri, 28 Aug 2020 22:36:12 -0800 Received: from MTKMBS01N2.mediatek.inc (172.21.101.79) by MTKMBS62N1.mediatek.inc (172.29.193.41) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Fri, 28 Aug 2020 23:26:09 -0700 Received: from mtkcas07.mediatek.inc (172.21.101.84) by mtkmbs01n2.mediatek.inc (172.21.101.79) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Sat, 29 Aug 2020 14:26:01 +0800 Received: from [172.21.77.33] (172.21.77.33) by mtkcas07.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Sat, 29 Aug 2020 14:26:02 +0800 Message-ID: <1598682362.14037.28.camel@mtkswgap22> Subject: Re: [PATCH v1 1/1] driver: watchdog: Add mtk_wdt_init for mediatek watchdog hw init From: Freddy.Hsin To: Guenter Roeck Date: Sat, 29 Aug 2020 14:26:02 +0800 In-Reply-To: References: <1598600968-28498-1-git-send-email-freddy.hsin@mediatek.com> <1598600968-28498-2-git-send-email-freddy.hsin@mediatek.com> X-Mailer: Evolution 3.2.3-0ubuntu6 MIME-Version: 1.0 X-TM-SNTS-SMTP: 6B6BA55B1AE0D64803E09E8B3B9BC22621E37215DCECAB7005722416B9C2EF1F2000:8 X-MTK: N X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200829_023640_197454_CFDDCF71 X-CRM114-Status: GOOD ( 30.45 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-watchdog@vger.kernel.org, wsd_upstream@mediatek.com, chun-hung.wu@mediatek.com, kuohong.wang@mediatek.com, linux-kernel@vger.kernel.org, linux-mediatek@lists.infradead.org, Matthias Brugger , chang-an.chen@mediatek.com, Wim Van Sebroeck , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, 2020-08-28 at 07:26 -0700, Guenter Roeck wrote: > On 8/28/20 12:49 AM, Freddy Hsin wrote: > > 1. add a hw initialization function > > 2. enable/disable the watchdog depends on the original hw setting > > 3. set WDOD_HW_RUNNING in start function in order to start > > kicker after driver probe and clear the bit in stop function > > > > Change-Id: I25aa797f3b88288f26984455e499e599e27f09fa > > Signed-off-by: Freddy Hsin > > The subject is misleading - what this really does it to honor > that/if a watchdog is already running. However, WDOG_HW_RUNNING > should not generally be set/cleared in the start/stop function. > Also, calling mtk_wdt_stop is pointless if WDT_MODE_EN is not set, > since clearing WDT_MODE_EN is all it does. On top of that, > setting WDOG_HW_RUNNING in the probe function requires that > max_hw_heartbeat_ms is set (instead of max_timeout). > > So if you really want to honor that the watchdog is already running > at boot, you would have to initialize max_hw_heartbeat_ms, set > WDOG_HW_RUNNING explicitly, and possibly call the ping function > before changing the timeout. > > Thanks, > Guenter Hi Guenter, Thanks for you suggestion. I will submit a new patch according to your advice. The purpose of this patch is to control WDT_MODE_EN in the first stage of preloader bring up, and it should not be disabled afterward to prevent the system freeze and cannot be reset, so remove the mtk_wdt_stop function and keep the original state set in preloader. > > > --- > > drivers/watchdog/mtk_wdt.c | 22 +++++++++++++++++++++- > > 1 file changed, 21 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/watchdog/mtk_wdt.c b/drivers/watchdog/mtk_wdt.c > > index d6a6393..59b5061 100644 > > --- a/drivers/watchdog/mtk_wdt.c > > +++ b/drivers/watchdog/mtk_wdt.c > > @@ -57,6 +57,9 @@ > > static bool nowayout = WATCHDOG_NOWAYOUT; > > static unsigned int timeout; > > > > +static int mtk_wdt_start(struct watchdog_device *wdt_dev); > > +static int mtk_wdt_stop(struct watchdog_device *wdt_dev); > > + > > struct mtk_wdt_dev { > > struct watchdog_device wdt_dev; > > void __iomem *wdt_base; > > @@ -148,6 +151,19 @@ static int toprgu_register_reset_controller(struct platform_device *pdev, > > return ret; > > } > > > > +static int mtk_wdt_init(struct watchdog_device *wdt_dev) > > +{ > > + struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev); > > + void __iomem *wdt_base; > > + > > + wdt_base = mtk_wdt->wdt_base; > > + > > + if (readl(wdt_base + WDT_MODE) & WDT_MODE_EN) > > + mtk_wdt_start(wdt_dev); > > + else > > + mtk_wdt_stop(wdt_dev); > > +} > > + > > static int mtk_wdt_restart(struct watchdog_device *wdt_dev, > > unsigned long action, void *data) > > { > > @@ -206,6 +222,8 @@ static int mtk_wdt_stop(struct watchdog_device *wdt_dev) > > reg |= WDT_MODE_KEY; > > iowrite32(reg, wdt_base + WDT_MODE); > > > > + clear_bit(WDOG_HW_RUNNING, &wdt_dev->status); > > + > > return 0; > > } > > > > @@ -225,6 +243,8 @@ static int mtk_wdt_start(struct watchdog_device *wdt_dev) > > reg |= (WDT_MODE_EN | WDT_MODE_KEY); > > iowrite32(reg, wdt_base + WDT_MODE); > > > > + set_bit(WDOG_HW_RUNNING, &wdt_dev->status); > > + > > return 0; > > } > > > > @@ -274,7 +294,7 @@ static int mtk_wdt_probe(struct platform_device *pdev) > > > > watchdog_set_drvdata(&mtk_wdt->wdt_dev, mtk_wdt); > > > > - mtk_wdt_stop(&mtk_wdt->wdt_dev); > > + mtk_wdt_init(&mtk_wdt->wdt_dev); > > > > watchdog_stop_on_reboot(&mtk_wdt->wdt_dev); > > err = devm_watchdog_register_device(dev, &mtk_wdt->wdt_dev); > > > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel