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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DA78CC433FE for ; Tue, 8 Nov 2022 08:20:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232910AbiKHIUV (ORCPT ); Tue, 8 Nov 2022 03:20:21 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37686 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232641AbiKHIUU (ORCPT ); Tue, 8 Nov 2022 03:20:20 -0500 Received: from mga17.intel.com (mga17.intel.com [192.55.52.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 96A5F2DE3 for ; Tue, 8 Nov 2022 00:20:19 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1667895619; x=1699431619; h=message-id:date:mime-version:subject:to:references:cc: from:in-reply-to:content-transfer-encoding; bh=pQlnMMCIRyEi4cVteHCjIdZ89vgIq6S/6CwX7fJFQhM=; b=ZoDZJSGBofahMZtaB7VkW/qJHOXLJ8No0+lyrOzDQiyosbMtY26jYDeT +No1PfwlV025m4wpon3VNRKIkeSBGjg69IIH4pPRUL5FhaCVrMqJBuxWL VQJAp+eES7/ieWBYFcbqL/LrNEsG/+3QAnlVajhnks+HOhUf/jVsyoVB8 mnsU0lxis2V1LVABcU47UV9zMgLRUXfyloyGcoYBvMorUTaZP3qvwFJgn Ps1ZbdITCKWs5vwGecLnGvUjKH5+Le1uotss07whoZfwwAJ8nua96piv6 Q3YB3yfhiShjosFBCB9bIP+YEsElQkVvmEP2AhSs+BxxFEaixaqCsCErd A==; X-IronPort-AV: E=McAfee;i="6500,9779,10524"; a="291026087" X-IronPort-AV: E=Sophos;i="5.96,147,1665471600"; d="scan'208";a="291026087" Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Nov 2022 00:20:19 -0800 X-IronPort-AV: E=McAfee;i="6500,9779,10524"; a="725479003" X-IronPort-AV: E=Sophos;i="5.96,147,1665471600"; d="scan'208";a="725479003" Received: from ahunter6-mobl1.ger.corp.intel.com (HELO [10.0.2.15]) ([10.252.56.164]) by fmsmga003-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Nov 2022 00:20:18 -0800 Message-ID: Date: Tue, 8 Nov 2022 10:20:14 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Firefox/102.0 Thunderbird/102.4.2 Subject: Re: Question about EMMC CMDQ HOST CONTROLLER INTERFACE (CQHCI) DRIVER Content-Language: en-US To: =?UTF-8?B?SnlhbiBDaG91IFvlkajoirflrold?= References: <5842d536cb0d4086a225ea0fa2d42e72@realtek.com> Cc: linux-mmc From: Adrian Hunter Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki In-Reply-To: <5842d536cb0d4086a225ea0fa2d42e72@realtek.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-mmc@vger.kernel.org On 8/11/22 09:25, Jyan Chou [周芷安] wrote: > Hello Adrian Hunter, > > We are now using the upstream code of EMMC CMDQ HOST CONTROLLER INTERFACE (CQHCI) DRIVER, but we found that the existing driver cannot support the limitation of Synopsys IP. > > Synopsys IP has a description on their data book " While using DMA, the host memory data buffer size and start address must not exceed 128 MB". > > I am wondering whether there is a method or patch that can fix this boundary limitation. > Thanks. > Best Regards, > Jyan Chou Hello Jyan Chou I am not clear on what the exact limitation is. The driver never uses buffers as big as 128 MB. To restrict DMA to low memory addresses a DMA mask can be used. But perhaps you mean not to cross a 128 MB boundary? Please cc your questions to the linux kernel mmc mailing list: linux-mmc@vger.kernel.org because others can answer too. Regards Adrian