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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 ECF13C31E5B for ; Tue, 18 Jun 2019 22:48:58 +0000 (UTC) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C7D0620863 for ; Tue, 18 Jun 2019 22:48:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C7D0620863 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from mail.linux-foundation.org (localhost [127.0.0.1]) by mail.linuxfoundation.org (Postfix) with ESMTP id ACDF6DDF; Tue, 18 Jun 2019 22:48:58 +0000 (UTC) Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 1C18BDDE for ; Tue, 18 Jun 2019 22:48:58 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mga18.intel.com (mga18.intel.com [134.134.136.126]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id A236E180 for ; Tue, 18 Jun 2019 22:48:57 +0000 (UTC) X-Amp-Result: UNSCANNABLE X-Amp-File-Uploaded: False Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga106.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 18 Jun 2019 15:48:57 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.63,390,1557212400"; d="scan'208";a="160196365" Received: from ranerica-svr.sc.intel.com ([172.25.110.23]) by fmsmga008.fm.intel.com with ESMTP; 18 Jun 2019 15:48:56 -0700 Date: Tue, 18 Jun 2019 15:48:35 -0700 From: Ricardo Neri To: Thomas Gleixner Subject: Re: [RFC PATCH v4 04/21] x86/hpet: Add hpet_set_comparator() for periodic and one-shot modes Message-ID: <20190618224835.GF30488@ranerica-svr.sc.intel.com> References: <1558660583-28561-1-git-send-email-ricardo.neri-calderon@linux.intel.com> <1558660583-28561-5-git-send-email-ricardo.neri-calderon@linux.intel.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) Cc: Kate Stewart , "Ravi V. Shankar" , x86@kernel.org, Ashok Raj , Peter Zijlstra , Philippe Ombredanne , Randy Dunlap , linux-kernel@vger.kernel.org, Stephane Eranian , Ricardo Neri , "Rafael J. Wysocki" , iommu@lists.linux-foundation.org, Tony Luck , "H. Peter Anvin" , Andi Kleen , Borislav Petkov , Ingo Molnar X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: iommu-bounces@lists.linux-foundation.org Errors-To: iommu-bounces@lists.linux-foundation.org On Fri, Jun 14, 2019 at 08:17:14PM +0200, Thomas Gleixner wrote: > On Thu, 23 May 2019, Ricardo Neri wrote: > > +/** > > + * hpet_set_comparator() - Helper function for setting comparator register > > + * @num: The timer ID > > + * @cmp: The value to be written to the comparator/accumulator > > + * @period: The value to be written to the period (0 = oneshot mode) > > + * > > + * Helper function for updating comparator, accumulator and period values. > > + * > > + * In periodic mode, HPET needs HPET_TN_SETVAL to be set before writing > > + * to the Tn_CMP to update the accumulator. Then, HPET needs a second > > + * write (with HPET_TN_SETVAL cleared) to Tn_CMP to set the period. > > + * The HPET_TN_SETVAL bit is automatically cleared after the first write. > > + * > > + * For one-shot mode, HPET_TN_SETVAL does not need to be set. > > + * > > + * See the following documents: > > + * - Intel IA-PC HPET (High Precision Event Timers) Specification > > + * - AMD-8111 HyperTransport I/O Hub Data Sheet, Publication # 24674 > > + */ > > +void hpet_set_comparator(int num, unsigned int cmp, unsigned int period) > > +{ > > + if (period) { > > + unsigned int v = hpet_readl(HPET_Tn_CFG(num)); > > + > > + hpet_writel(v | HPET_TN_SETVAL, HPET_Tn_CFG(num)); > > + } > > + > > + hpet_writel(cmp, HPET_Tn_CMP(num)); > > + > > + if (!period) > > + return; > > TBH, I hate this conditional handling. What's wrong with two functions? There is probably nothing wrong with two functions. I can split it into hpet_set_comparator_periodic() and hpet_set_comparator(). Perhaps the latter is not needed as it would be a one-line function; you have suggested earlier to avoid such small functions. > > > + > > + /* > > + * This delay is seldom used: never in one-shot mode and in periodic > > + * only when reprogramming the timer. > > + */ > > + udelay(1); > > + hpet_writel(period, HPET_Tn_CMP(num)); > > +} > > +EXPORT_SYMBOL_GPL(hpet_set_comparator); > > Why is this exported? Which module user needs this? It is not used anywhere else. I will remove this export. Thanks and BR, Ricardo _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu