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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 548D4CD4F49 for ; Fri, 14 Nov 2025 05:02:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=3B5y+sYm5sP4UrSKiyKYVoarVxgUD9FR3ci7tWNg9ZI=; b=pJ2ZZ8ZwWOHsix99Nj/2ZGdM5z 28Mr04cKPOKCgkDq+ilYVEDOglD+s0lqKIMETY4IDngdTT3n4XjieC6qXlfXwzhWin34lINs0vJsg rQQ6HW7Q9F4sKCe1vhZ1mGGcOQ9XIW57jZfETCHxCXmuQ3lahcHNRd5Pm2EvzzaLNG4k68BTdame8 6Zt05oExXRrAAQZhuCHhOj8RruqB6D/8ttlNbtf2M4K3Jv+hBS42h7UtndYHwnU2QaMSzfAEL+XDE 6oalh1eDD+f86ejMkZxNSYfOKPAUPFTQkmIuvEWeeX2PzHYtn/Po/oEjUXWv9yCzDZS0pideTd6b2 Lk2IcJPw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vJlwt-0000000BZrt-3Ic6; Fri, 14 Nov 2025 05:02:15 +0000 Received: from [50.53.43.113] (helo=[192.168.254.34]) by bombadil.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1vJlwr-0000000BZrS-3zdC; Fri, 14 Nov 2025 05:02:13 +0000 Message-ID: <0eb1a2b7-8064-4ac5-bcf8-b4898a8b5ac7@infradead.org> Date: Thu, 13 Nov 2025 21:02:13 -0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 13/13] coresight: docs: Document etm4x timestamp interval option To: James Clark , Suzuki K Poulose , Mike Leach , Alexander Shishkin , Jonathan Corbet , Leo Yan Cc: coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org References: <20251112-james-cs-syncfreq-v4-0-165ba21401dc@linaro.org> <20251112-james-cs-syncfreq-v4-13-165ba21401dc@linaro.org> Content-Language: en-US From: Randy Dunlap In-Reply-To: <20251112-james-cs-syncfreq-v4-13-165ba21401dc@linaro.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 11/12/25 7:22 AM, James Clark wrote: > Document how the new field is used, maximum value and the interaction > with SYNC timestamps. > > Signed-off-by: James Clark > --- > Documentation/trace/coresight/coresight.rst | 15 +++++++++++++-- > 1 file changed, 13 insertions(+), 2 deletions(-) > > diff --git a/Documentation/trace/coresight/coresight.rst b/Documentation/trace/coresight/coresight.rst > index 806699871b80..80b5ed09d69b 100644 > --- a/Documentation/trace/coresight/coresight.rst > +++ b/Documentation/trace/coresight/coresight.rst > @@ -613,8 +613,19 @@ They are also listed in the folder /sys/bus/event_source/devices/cs_etm/format/ > - Session local version of the system wide setting: :ref:`ETM_MODE_RETURNSTACK > ` > * - timestamp > - - Session local version of the system wide setting: :ref:`ETMv4_MODE_TIMESTAMP > - ` > + - Controls generation and interval of timestamps. > + > + 0 = off, 1 = maximum interval .. 15 = minimum interval. > + > + Values 1 - 14 use a counter that decrements every cycle to generate a > + timestamp on underflow. The reload value for the counter is 2 raised to > + the power of timestamp interval - 1. If the value is 1 then the reload > + value is 1, if the value is 11 then the reload value is 1024 etc. value = 11: 2^11-1 = 2047 Maybe add some parens? -- ~Randy