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=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 6360BC55199 for ; Mon, 27 Apr 2020 06:14:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2D916206B6 for ; Mon, 27 Apr 2020 06:14:31 +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="uw/Hyy/C" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726551AbgD0GOa (ORCPT ); Mon, 27 Apr 2020 02:14:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41566 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726231AbgD0GOa (ORCPT ); Mon, 27 Apr 2020 02:14:30 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 29039C061A0F; Sun, 26 Apr 2020 23:14:30 -0700 (PDT) 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; bh=on8z9Ittpq1vG37rq3n1q4CJliIUajEmB/VdF44xHeQ=; b=uw/Hyy/CILJmKzp8JDfO1Klwcg VsO26rPAJeY0W75RwNS00uBvPN9mhqPEW1H4Gf7jDw3hlSJ75YTuwWiY8tgunyhkMYdoWK4oRYxWk kjp0RIB3jIdujYj3Jugd3VUcrXfDtx4U3yfZON1EgNUrUCMPIpkPJcPMx0hM+DC3f0XB0zLh7sged 8fTlZEpUgTEekHOKNHYavqlCoOHUHJWHXMfENgodlw8rNFaxC3HHH9QnrTKdOKpVRBMZoWOGzchP6 6m48xWU+VV23DpSBXPfcMROJpUvLVBPxAwBOHGG7vSmLHZSU6gYiJzD3Gd9G1ygNNHKuoCtwMTVnC ixCPqw3g==; Received: from hch by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jSx2A-0001n6-8B; Mon, 27 Apr 2020 06:14:26 +0000 Date: Sun, 26 Apr 2020 23:14:26 -0700 From: Christoph Hellwig To: rui_feng@realsil.com.cn Cc: arnd@arndb.de, gregkh@linuxfoundation.org, ulf.hansson@linaro.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org Subject: Re: [PATCH] mmc: rtsx: Add SD Express mode support for RTS5261 Message-ID: <20200427061426.GA11270@infradead.org> References: <1587864346-3144-1-git-send-email-rui_feng@realsil.com.cn> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1587864346-3144-1-git-send-email-rui_feng@realsil.com.cn> 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 Sun, Apr 26, 2020 at 09:25:46AM +0800, rui_feng@realsil.com.cn wrote: > From: Rui Feng > > RTS5261 support legacy SD mode and SD Express mode. > In SD7.x, SD association introduce SD Express as a new mode. > SD Express mode is distinguished by CMD8. > Therefore, CMD8 has new bit for SD Express. > SD Express is based on PCIe/NVMe. > RTS5261 uses CMD8 to switch to SD Express mode. So how does this bit work? They way I imagined SD Express to work is that the actual SD Card just shows up as a real PCIe device, similar to say Thunderbolt.