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=-7.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,URIBL_BLOCKED,USER_AGENT_GIT autolearn=no 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 590D0C4363D for ; Thu, 24 Sep 2020 14:17:02 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 E5F6F221EB for ; Thu, 24 Sep 2020 14:17:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="Mxxn0EVR"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=mediatek.com header.i=@mediatek.com header.b="E17bSWnd" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E5F6F221EB Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=mediatek.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To:Message-ID:Date: Subject:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=BA/TxEN+TkdCjB8CvcIWjGaQrUh/DL39gnQ9TRUEutU=; b=Mxxn0EVRUsovwdcVsl/baD4Cy 6N8JwXIf3Cu/6SwaaE427ziIJUM/0Yj0ZfKFnwb3JDLIqi/xRWj50s2E7febN9mJYhYWA4zMecB+O BgWLROnJb1kgiBDHDBdVK9WORnvT945tQdxPs6TTcs3y9j4vIjUA7JKjcUrpyMq5Jl5GiOmrBfy/e cBDDtDgkAwC6aYuQbs6v2+jHrGtB4etyZUqXIzRklQJf/nNuTwvYTUi1eh1qz0L4YAhA4Po2eY7iK AlGUYfGdpUCFpapCrYodi0t0BwEX0wDMJ5rFSdVxgPwor/vhSzSM7cH8QDk3N2Hx6je3V6jV6YHxE 9udAkSsjQ==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kLS1u-0003TM-OV; Thu, 24 Sep 2020 14:15:27 +0000 Received: from mailgw01.mediatek.com ([216.200.240.184]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kLS1p-0003S8-Ui; Thu, 24 Sep 2020 14:15:24 +0000 X-UUID: 8b9549d922d34729afd0145909cc4566-20200924 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=mediatek.com; s=dk; h=Content-Transfer-Encoding:Content-Type:MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:CC:To:From; bh=3gDT2fSDKlN+/xLxFu5tIv5oC9wVXrVAOCd+NyaKVj0=; b=E17bSWndZCM03aK+gvO72kKz8/wL/wftTH7/l+wx0vh7Q7PUylP62BoJaq2zwoT4JeCEOj7EbtHks0QYNs19pnM9E+1qeHP9RityhyjjuLcjRisuwTJSH6BdHWDQqf+FnApCIwOUoIFkkGTzCFWbOQMtJvZA8pbrfLUI19OTOXE=; X-UUID: 8b9549d922d34729afd0145909cc4566-20200924 Received: from mtkcas67.mediatek.inc [(172.29.193.45)] by mailgw01.mediatek.com (envelope-from ) (musrelay.mediatek.com ESMTP with TLSv1.2 ECDHE-RSA-AES256-SHA384 256/256) with ESMTP id 1955240399; Thu, 24 Sep 2020 06:15:16 -0800 Received: from MTKMBS06N1.mediatek.inc (172.21.101.129) by MTKMBS62N2.mediatek.inc (172.29.193.42) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Thu, 24 Sep 2020 07:15:14 -0700 Received: from MTKCAS06.mediatek.inc (172.21.101.30) by mtkmbs06n1.mediatek.inc (172.21.101.129) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Thu, 24 Sep 2020 22:15:14 +0800 Received: from mtksdccf07.mediatek.inc (172.21.84.99) by MTKCAS06.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Thu, 24 Sep 2020 22:15:11 +0800 From: Phil Chang To: Catalin Marinas Subject: Re: Re: [PATCH] [PATCH] ARM64: Setup DMA32 zone size by bootargs Date: Thu, 24 Sep 2020 22:15:14 +0800 Message-ID: <20200924141514.23930-1-phil.chang@mediatek.com> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20200916133324.6280-1-phil.chang@mediatek.com> References: <20200916133324.6280-1-phil.chang@mediatek.com> MIME-Version: 1.0 X-MTK: N X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200924_101522_680605_2E5F5BA2 X-CRM114-Status: UNSURE ( 8.29 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Alix Wu , YJ Chiang , Phil Chang , linux-kernel@vger.kernel.org, linux-mediatek@lists.infradead.org, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Actually, In a embedded system with 3GB memory, the memory bus width is not the same among the 3GB. (The first 2GB is 48-bit wide, and the latter 1GB is 16-bit wide.) For memory throughput reason of hardware IPs, we need allocate memory from the first 2GB for the hardware IPs. And that is why we setup the first 2GB as DMA_ZONE, and use GFP_DMA to allocate memory from the range. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel