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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 C3A61C31E5B for ; Tue, 18 Jun 2019 16:27:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9605D2054F for ; Tue, 18 Jun 2019 16:27:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="QSmzxcCL"; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="NDg+fW5E" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729491AbfFRQ15 (ORCPT ); Tue, 18 Jun 2019 12:27:57 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:56778 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729295AbfFRQ15 (ORCPT ); Tue, 18 Jun 2019 12:27:57 -0400 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id 0E56C6028D; Tue, 18 Jun 2019 16:27:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1560875276; bh=AZGWFNkJxbGoXKKAkuxIYIe9MRoN3IT0Racj+5YQtMI=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=QSmzxcCLou2m8qnIksmWjuepW2C7BCTNiW75mvNWBrHRmttDyr3aFQ1T5yyEuJQ6K joROgUtcscmgAhk5lP6gUL/6IZZ2b9VhfBdp7X6s/cLCY4RoEgjKT3jpon85VTXsdF U88nXf+z4KNrw8wB/Zdc1A5/mAs9lQQ/xnAcKwjs= Received: from [192.168.1.5] (unknown [122.164.143.169]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: sricharan@smtp.codeaurora.org) by smtp.codeaurora.org (Postfix) with ESMTPSA id 7F220602BC; Tue, 18 Jun 2019 16:27:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1560875275; bh=AZGWFNkJxbGoXKKAkuxIYIe9MRoN3IT0Racj+5YQtMI=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=NDg+fW5EB2QgBv/KAQ4L5YoyOcCI/KP0uNrDznsvlpPaepCMo+H3dyqeK9wKTIp9s Gqj6v0qEGQZNkcUPb4tJTbRMndmC1vtTvujQRiyc+55REkPu8v9IYs+iG55nx8zW2X ELuYbvW6D4ck6bv+3+YkCsgt9plraM5Gis3Ble5E= DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 7F220602BC Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=sricharan@codeaurora.org Subject: Re: [PATCH] dmaengine: qcom-bam: fix circular buffer handling To: Srinivas Kandagatla , vkoul@kernel.org Cc: dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org References: <20190614142012.31384-1-srinivas.kandagatla@linaro.org> <2d370a33-fa16-45ca-cf82-9d775349f806@codeaurora.org> <544851f6-58b8-2506-01ce-5c4d1f93fb3c@linaro.org> From: Sricharan R Message-ID: Date: Tue, 18 Jun 2019 21:57:49 +0530 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: <544851f6-58b8-2506-01ce-5c4d1f93fb3c@linaro.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: dmaengine-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org On 6/18/2019 8:42 PM, Srinivas Kandagatla wrote: > > > On 18/06/2019 15:56, Sricharan R wrote: >>    So MAX_DESCRIPTORS is used in driver for masking head/tail pointers. >>    That's why we have to pass MAX_DESCRIPTORS + 1 so that it works >>    when the Macros does a size - 1 > Isn't that incorrect to do that, pretending to have more descriptors than we actually have? > The Macro's expect that buffer size is power of 2. So we are infact passing the actual correct size ( MAX_DESCRIPTORS + 1 = 4096) Regards, Sricharan -- "QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation