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=-5.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,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 3DDF3C072B1 for ; Thu, 30 May 2019 05:53:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EFC5A24B81 for ; Thu, 30 May 2019 05:53:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="ViocBpNv" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726896AbfE3FxA (ORCPT ); Thu, 30 May 2019 01:53:00 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:37416 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725961AbfE3Fw7 (ORCPT ); Thu, 30 May 2019 01:52:59 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=oHqVEIhqCwMex8GKlVQDi4KtDcsBFBMe3TYDNP4SewE=; b=ViocBpNvOg+Novr+owM9IAtqL mxbnKycuk76UKiKY6BtJbNuFG50XpOQ1P37OqQgdiTBUMuiMEHvHRfYRyfGrj3aGD6js3FV6dFkUl f6N9V1KXtGVAHiydLyhDrKNf5C0qB6cyHE0Q19ozUBT1lHYD9xSdq0JUszRtyynjiGEFYgeWdEUqX gdkPRik7oOTm+LbhV2kXM/2bF7nNRjHcTomKMX6TJIZzHnFWRKgOPOLCWJ5BFOciGFBpx5H/OVwNB EEumZRHqRHxurSmaxBNu3VEedlPsCDfV/dzoGjABVbmKtBPW0qZCqXFtdR50umTuzzd2TAz6t3cEX SAcNGPQxg==; Received: from hch by bombadil.infradead.org with local (Exim 4.90_1 #2 (Red Hat Linux)) id 1hWDzm-0003GK-GA; Thu, 30 May 2019 05:52:58 +0000 Date: Wed, 29 May 2019 22:52:58 -0700 From: Christoph Hellwig To: Nick Hu Cc: greentime@andestech.com, palmer@sifive.com, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, green.hu@gmail.com Subject: Re: [PATCH] riscv: Fix udelay in RV32. Message-ID: <20190530055258.GA7170@infradead.org> References: <381ee6950c84b868ca6a3c676eb981a1980889a3.1559035050.git.nickhu@andestech.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <381ee6950c84b868ca6a3c676eb981a1980889a3.1559035050.git.nickhu@andestech.com> User-Agent: Mutt/1.9.2 (2017-12-15) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 28, 2019 at 05:26:49PM +0800, Nick Hu wrote: > In RV32, udelay would delay the wrong cycle. > When it shifts right "UDELAY_SHITFT" bits, it > either delays 0 cycle or 1 cycle. It only works > correctly in RV64. Because the 'ucycles' always > needs to be 64 bits variable. Please use up all your ~72 chars per line in the commit log. > diff --git a/arch/riscv/lib/delay.c b/arch/riscv/lib/delay.c > index dce8ae24c6d3..da847f49fb74 100644 > --- a/arch/riscv/lib/delay.c > +++ b/arch/riscv/lib/delay.c > @@ -88,7 +88,7 @@ EXPORT_SYMBOL(__delay); > > void udelay(unsigned long usecs) > { > - unsigned long ucycles = usecs * lpj_fine * UDELAY_MULT; > + unsigned long long ucycles = (unsigned long long)usecs * lpj_fine * UDELAY_MULT; And this creates a way too long line. Pleaase use u64 instead of unsigned long long to clarify the intention while also fixing the long lines.