From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A50D9C55179 for ; Tue, 27 Oct 2020 09:21:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 40AE32224E for ; Tue, 27 Oct 2020 09:21:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="R/zY8H/5" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2509213AbgJ0JVp (ORCPT ); Tue, 27 Oct 2020 05:21:45 -0400 Received: from mail-wr1-f67.google.com ([209.85.221.67]:45709 "EHLO mail-wr1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2404528AbgJ0JVp (ORCPT ); Tue, 27 Oct 2020 05:21:45 -0400 Received: by mail-wr1-f67.google.com with SMTP id e17so983962wru.12; Tue, 27 Oct 2020 02:21:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=z186JCjjaFAvCwc5lnsVqYkaLznjMGEXbtq2BCuMZUU=; b=R/zY8H/5RPpLm3egn2ta5iUiZIwEuBzVCXPw+Lg91p9vvPRrGBl2piv7GEZSMLjpfE ueb6cEurQZV2EBfy0xfbCkbpmsNtkSng1lab2hKeN2VHcpLcwer2p7ySHksmrwhHzCaA isMvam17ZW1fhjfjzEHD5oFU6pms1bfxiLTPWXI+8vas75xeAxnyN6HBUxnJddury4Ba VKWdjVUTfQkcLzGv49PIDfpjKrMcfepltj5TeQAFbPfSMjYD6JmZl6Xjj87LZL2tsimi waq91nLJhvvTJFvEBLnpZF0d/90+4zf+GaLd9IxeD7YcM72URPo04KwM/wTDY9F+0kp6 Gvng== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=z186JCjjaFAvCwc5lnsVqYkaLznjMGEXbtq2BCuMZUU=; b=dL/AnY3VCiQMI+C7MWRbLlwZl5Y9zsTmWmO2TU+X2hRhCU+URVIsWi0J6xzzpG6pbP QH9LKoGjKuv0PjNrAX1TmC0YrXmsZmimWV8KPfmRT3lffDT0xA9Do2Snh1WPhuL2L2q+ wwmnO3YyCVdtL/wYHipD6LVspFohNrMZgByuRt7n3PHmkzwJOQMzbmcW8xhOch9ksVtH 4sTjqYbibcufugJ7+qqG3lpebPKzSOTHLYUZJg7XflM58GPY34E0p+nuXPPMVaFD1Cxv kkAR0Emoga2ZpZa0yWFt3OK394Mb9xFSAXFVyqMJ9KDuF54V96fu98c9Igv2LSNERjBl z6ug== X-Gm-Message-State: AOAM533rFWZoq/kjhxNcYMTMDKjOiEbYdpej4GPRr4Oh3AYgM/rVZxYU YztejqjRDsQ8No5ohmcfcP9jolrxL9pF2vbpHek= X-Google-Smtp-Source: ABdhPJzLZIQloIRWMS3CKSzfJxNeKxMuq7Fc6dt5T+aLr/rd4csjRbbxN9ImnAaNVvWLX9fEwgmSwsjd/e6BlOpueGQ= X-Received: by 2002:a5d:554b:: with SMTP id g11mr1665906wrw.370.1603790502743; Tue, 27 Oct 2020 02:21:42 -0700 (PDT) MIME-Version: 1.0 References: <20201026080919.28413-1-zhang.lyra@gmail.com> <20201026080919.28413-3-zhang.lyra@gmail.com> <1bb8a3cf-5cdf-2c7f-29a2-3307f0de7cb0@roeck-us.net> In-Reply-To: <1bb8a3cf-5cdf-2c7f-29a2-3307f0de7cb0@roeck-us.net> From: Chunyan Zhang Date: Tue, 27 Oct 2020 17:21:06 +0800 Message-ID: Subject: Re: [PATCH 2/3] watchdog: sprd: change timeout value from 1000 to 2000 To: Guenter Roeck Cc: Wim Van Sebroeck , linux-watchdog@vger.kernel.org, Linux Kernel Mailing List , Orson Zhai , Baolin Wang , Chunyan Zhang , jingchao.ye@unisoc.com, ling_ling.xu@unisoc.com, xiaoqing.wu@unisoc.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 26 Oct 2020 at 22:36, Guenter Roeck wrote: > > On 10/26/20 1:09 AM, Chunyan Zhang wrote: > > From: Lingling Xu > > > > Because cpu_relax() takes different time on different SoCs, for some rare > > cases, it would take more than 1000 cycles for waitting load operation > > waiting Ok. > > > finished. The result of many times testing verified that changing the > > timeout value to 2000 can solve the issue. > > > > This is just a kludge that doesn't address the underlying problem. > As the wait loop states, "Waiting the load value operation done, > it needs two or three RTC clock cycles". This means the loop > should wait for a maximum number of clock cycles, and not run > as hot loop. If we assume that clk_get_rate() returns the clock > frequency, that frequency can be used to determine how long this > needs to be retried. It might also make sense - depending on how > long this actually takes - to use usleep_range() instead of > cpu_relax() to avoid the hot loop. Agree, using usleep_range() instead makes more sense, I will look into that. Thanks for your review. Chunyan > > Guenter > > > Fixes: 477603467009 ("watchdog: Add Spreadtrum watchdog driver") > > Signed-off-by: Lingling Xu > > Signed-off-by: Chunyan Zhang > > --- > > drivers/watchdog/sprd_wdt.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/watchdog/sprd_wdt.c b/drivers/watchdog/sprd_wdt.c > > index f3c90b4afead..4f2a8c6d6485 100644 > > --- a/drivers/watchdog/sprd_wdt.c > > +++ b/drivers/watchdog/sprd_wdt.c > > @@ -53,7 +53,7 @@ > > > > #define SPRD_WDT_CNT_HIGH_SHIFT 16 > > #define SPRD_WDT_LOW_VALUE_MASK GENMASK(15, 0) > > -#define SPRD_WDT_LOAD_TIMEOUT 1000 > > +#define SPRD_WDT_LOAD_TIMEOUT 2000 > > > > struct sprd_wdt { > > void __iomem *base; > > >