From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f179.google.com (mail-pg1-f179.google.com [209.85.215.179]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3772B592204 for ; Wed, 9 Sep 2026 21:14:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.179 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788988494; cv=none; b=mQpuGkwWHd6Jn5G3LKa3L8w9covbubYs7KMzAR4yk9/kuI4OtAB5tBXco6oWdTs9tik63D76buRIiW6u7XUxGSderwd7Xr+ErCEJpyUjAxRarq+XSGMgoD8fIBNNB0NBBOy9k/Eanv7lODJHl1rEZhPCSc9kNU+jYGn23AR6Hpo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788988494; c=relaxed/simple; bh=MnEDALe6uwOaXe/sMQyhmeqQexZ0FL6u6wwzWWIRwuQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Kn64kwxISabjLvtavANngG5rUCy5IYprO+2m6523o2TywgjNVYKa8Jju+8PIH+4BuMOCoCKKjgyx6c4kBUl8awlS9KIUkkBQWqc0wTCZZinHIqQw9Y2b3rS8sgq0bsJLnvj7vsz7hpz/9udlB/9KQ+CL94PXA1jB/PwtA9tQqbo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=roeck-us.net; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=qnw1bVAa; arc=none smtp.client-ip=209.85.215.179 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=roeck-us.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="qnw1bVAa" Received: by mail-pg1-f179.google.com with SMTP id 41be03b00d2f7-cc149372c14so3335288a12.1 for ; Wed, 09 Sep 2026 14:14:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1788988483; x=1789593283; darn=vger.kernel.org; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:sender:from:to:cc :subject:date:message-id:reply-to:content-type; bh=yxgxA+Z3MXKBfp6ZxROey+7ykV72GFbg4Bcj0PBfYIk=; b=qnw1bVAaD2BRxJaur85L8eho8U1QSX2kgzNHSlYg+1wsNIElEhl5x1euBbrIwOgeUM N7Fuo3ZoEF8f4KA0bo2rsjLGBDCxx/ftiamvGvuivwuoZ0G4jcCqMeOFvLmy514Q852x LEOR7nWm8LTKHeq9rBiUX8Mkdjgk3Xfac3ln4e80+s+kd2l/YIZHK16EMJnrUu5NVLhq d2W1qttEzEqD2dbRxPkbwmbsXMBoQRr4UvsUrWbUZURbcTN46in4RklMyObnh+/Vi5JF tKeQVBAr7Em3ewzMMLEORMSylKKd6IN/bsJtSCxYsj6E4DuhpbVkq3ZZkqqlVyQA5nhU m7/w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1788988483; x=1789593283; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:sender:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=yxgxA+Z3MXKBfp6ZxROey+7ykV72GFbg4Bcj0PBfYIk=; b=cr4OfZFOnnnYOsT1YyiO0MVLTjXmcuuBYhSYFBosEmcJ4K8VHFRTAWPL5Dfu/wbsGO yEXZ7UpQHf7YfSgmvTapK9V1wNbaKdEju8/JjSGZNT1b6gl9xRXrSr5e70lvNpHSkwpf 7eOJFyFEdl5y/nBgnQ6Q3ZNB6mETWoNwMJlfl+DF108mGf9HLn1A5OKEUAcGUcRElRih TK9tNZSE71A4968xlHkNNXLjrzUmH2B0byRNN5J27P29tQ3UZL+eB87+zxsPvU4mjf67 3mImboUmPQGxdaXgHibsYWBGTyKaZDESRhXCiZ30MxNQBBVGmY+tUfQAWg90t/b4GnnT we3w== X-Forwarded-Encrypted: i=1; AKwUvBxCe1Vl+TBsizxYEVB1NlF2OmFz8lNZAJVhxE2kWSR6P+jQSf0i+uN7spgs+8ypy/AdItQtJDOCPApM1vk=@vger.kernel.org X-Gm-Message-State: AFuF++kXBPIE4dY9gzOiFMxMd2JL3Pvp6hsnGSTAvAwnejLVaev6Yrhv EgB2l8G0PB6FR7XMw7NgvSl+njv3pzbjG4BpbAsOB9vXo77H/U9/9jav X-Gm-Gg: AYBFou1hGwI+lEu9X7mT/VU0Ck/0PLZ5et65GCM/8UNoqpj+63z8aWxQ4/QwgCi2k8p vaiOK4op37NqaHCCN1KVGSgejMUmSpdwOQX2/M3j7yGl5WNYXUboY4iezAf8LMWjWo+0dAvza8Y 6g5KusCRg7ve6r3S5OPi3a6CM2KsGqccMLjXhndfDuXjjJLl9GKzarWXjSXMWymstVzPCOelE6P spaAzpDKTMvQVVB9Z1Ks6mf/q66bCRDks/Q3C+M2IqHiN/c4ChZl6ErigE9yf/t9POmFqRQ6AmD AwBUX4m7VfvL4XJOMc5iZwJ1MzwW3Wzs26YQx6aefJoYlCY52WYIYdGCVwP19WI+cy+jzCvd8rR +5Ni244m9zJ+Dk2jpAK0oZ6brbcY6D5OILTtbSE8zU1blj3AKdZmRf76cTyHBmoWmclG5mfWKdu DXZt2FI8Ht4s+L/+oljOz4AcNZfY7qgA92hRrCYVCzP6z7byGO1MTBE7Offplj98/icpmv2C82o ku/K/SVhnjnOBh3pC0gXVI= X-Received: by 2002:a17:90b:4c86:b0:395:5f43:4ec4 with SMTP id 98e67ed59e1d1-39b25f78ab8mr52972022a91.0.1788988483245; Wed, 09 Sep 2026 14:14:43 -0700 (PDT) Received: from server.roeck-us.net ([2600:1700:e321:62f0:da43:aeff:fecc:bfd5]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-39d770e39c1sm1379938a91.6.2026.09.09.14.14.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 09 Sep 2026 14:14:42 -0700 (PDT) Sender: Guenter Roeck Date: Wed, 9 Sep 2026 14:14:41 -0700 From: Guenter Roeck To: Tzung-Bi Shih Cc: Wim Van Sebroeck , Daniel Palmer , Romain Perier , linux-watchdog@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 4/9] watchdog: msc313e: Enable clock before accessing hardware registers Message-ID: References: <20260828161348.13212-1-tzungbi@kernel.org> <20260828161348.13212-5-tzungbi@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260828161348.13212-5-tzungbi@kernel.org> On Sat, Aug 29, 2026 at 12:13:43AM +0800, Tzung-Bi Shih wrote: > msc313e_wdt_probe() reads from hardware registers without ensuring the > required clock is enabled. Furthermore, if the bootloader leaves the > watchdog running, msc313e_wdt_probe() sets WDOG_HW_RUNNING without > increasing the clock's reference count. > > While the clock is currently supplied as a fixed clock by the device > tree (`xtal_div2` in arch/arm/boot/dts/sigmastar/mstar-v7.dtsi) which > masks the physical issue, this still violates the API usage. > > Call clk_prepare_enable() before reading WDT registers. If the WDT is > running, leave the clock enabled so the CCF reference counter is > balanced. > > Fixes: ffd264bd152c ("watchdog: msc313e: Check if the WDT was running at boot") > Signed-off-by: Tzung-Bi Shih Applied. Comment below. > --- > v2: > - Fix a clock leak issue in the error handling path (Sashiko reported). > > v1: https://lore.kernel.org/all/20260827044700.554333-3-tzungbi@kernel.org > --- > drivers/watchdog/msc313e_wdt.c | 23 +++++++++++++++++++++-- > 1 file changed, 21 insertions(+), 2 deletions(-) > > diff --git a/drivers/watchdog/msc313e_wdt.c b/drivers/watchdog/msc313e_wdt.c > index 8ce24df8e338..7c4593566781 100644 > --- a/drivers/watchdog/msc313e_wdt.c > +++ b/drivers/watchdog/msc313e_wdt.c > @@ -108,6 +108,7 @@ static int msc313e_wdt_probe(struct platform_device *pdev) > struct device *dev = &pdev->dev; > struct msc313e_wdt_priv *priv; > unsigned long rate; > + int ret; > > priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); > if (!priv) > @@ -133,9 +134,21 @@ static int msc313e_wdt_probe(struct platform_device *pdev) > priv->wdev.max_timeout = U32_MAX / rate; > priv->wdev.timeout = MSC313E_WDT_DEFAULT_TIMEOUT; > > + ret = clk_prepare_enable(priv->clk); > + if (ret) > + return ret; > + > /* If the period is non-zero the WDT is running */ > - if (readw(priv->base + REG_WDT_MAX_PRD_L) | (readw(priv->base + REG_WDT_MAX_PRD_H) << 16)) > + if (readw(priv->base + REG_WDT_MAX_PRD_L) | (readw(priv->base + REG_WDT_MAX_PRD_H) << 16)) { > set_bit(WDOG_HW_RUNNING, &priv->wdev.status); > + /* > + * Keep the clock enabled. The watchdog core will skip the next > + * start() and a future stop() will balance the CCF reference > + * count. > + */ > + } else { > + clk_disable_unprepare(priv->clk); > + } > > watchdog_set_drvdata(&priv->wdev, priv); > platform_set_drvdata(pdev, priv); > @@ -144,7 +157,13 @@ static int msc313e_wdt_probe(struct platform_device *pdev) > watchdog_stop_on_reboot(&priv->wdev); > watchdog_stop_on_unregister(&priv->wdev); > > - return devm_watchdog_register_device(dev, &priv->wdev); > + ret = devm_watchdog_register_device(dev, &priv->wdev); > + > + /* If the WDT is running and anything goes wrong, disable the clock. */ > + if (ret && test_bit(WDOG_HW_RUNNING, &priv->wdev.status)) > + clk_disable_unprepare(priv->clk); Curious. Does this mean that Sashiko complains either way ? Thanks, Guenter > + > + return ret; > } > > static int __maybe_unused msc313e_wdt_suspend(struct device *dev)