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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 477EAC432C3 for ; Thu, 28 Nov 2019 21:07:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1D6F0216F4 for ; Thu, 28 Nov 2019 21:07:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726569AbfK1VHb (ORCPT ); Thu, 28 Nov 2019 16:07:31 -0500 Received: from sauhun.de ([88.99.104.3]:46874 "EHLO pokefinder.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726558AbfK1VHb (ORCPT ); Thu, 28 Nov 2019 16:07:31 -0500 Received: from localhost (x4db74569.dyn.telefonica.de [77.183.69.105]) by pokefinder.org (Postfix) with ESMTPSA id 0F8472C039E; Thu, 28 Nov 2019 22:07:29 +0100 (CET) Date: Thu, 28 Nov 2019 22:07:28 +0100 From: Wolfram Sang To: Yoshihiro Shimoda Cc: linux-renesas-soc@vger.kernel.org Subject: Re: [PATCH RFC 4/4] mmc: host: renesas_sdhi_sys_dmac: Set dma_buswidth value to 32 byte Message-ID: <20191128210728.GA864@kunai> References: <1574403231-18512-1-git-send-email-yoshihiro.shimoda.uh@renesas.com> <1574403231-18512-5-git-send-email-yoshihiro.shimoda.uh@renesas.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="OgqxwSJOaUobr8KG" Content-Disposition: inline In-Reply-To: <1574403231-18512-5-git-send-email-yoshihiro.shimoda.uh@renesas.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-renesas-soc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-renesas-soc@vger.kernel.org --OgqxwSJOaUobr8KG Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Hi Shimoda-san, Interesting series! > - .dma_buswidth = DMA_SLAVE_BUSWIDTH_4_BYTES, > + .dma_buswidth = DMA_SLAVE_BUSWIDTH_32_BYTES, Two very high level questions: 1) can't we set dma_priv->dma_buswidth at runtime when we know what the card is capable of? Either DMA_SLAVE_BUSWIDTH_32_BYTES or DMA_SLAVE_BUSWIDTH_4_BYTES? Then we don't need to fallback to PIO. AFAIS, we only Gen2 sets .dma_buswidth in of_data, so we could even remove it from of_data entirely? 2) Just by grepping in mmc/hosts, I see that no driver uses DMA_SLAVE_BUSWIDTH_32_BYTES. Do you have an idea why? Because it is the convenient setting which works for all cards? Thanks and kind regards, Wolfram --OgqxwSJOaUobr8KG Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEOZGx6rniZ1Gk92RdFA3kzBSgKbYFAl3gNwsACgkQFA3kzBSg KbagxRAAjT+tabpNv2so/CUX8CLhHugj5nbuLpTLH7wO83Gsedt3COqxFlsVyKDN oYqUaUtGd/vuVsa9XXvrLtC1BwB3f9vbeb4k2OAbQhG5VHC/B6YwVv3ZiWTrpv+m ZzSRy5e/uzgk0gH0PG+YUXjuX9aSPW0Dg0UTfZnPwSodizrsZpyPazLU7mT5h0xV mhsWCoxuf+ZlVqFDOq/bNmJ6RLQyrCEFfkc0hxTGwh95XFPRYOWjtVtit2Nwdl+R F+hM4Y+8I+YfjgrOA7ck2U+Z9HbImwWdpnFk/yvmrHo1VS3A1KvrKhPA9FVAQxV5 Sg9nAsVGUGWJrujJCQ7bjAWfdIHtFEx4ePYI2UGLGBuZO86cmICGMRBANW3wbE1U bhGj+/Rz5XwnFiQoy5jgYu47lpcN4tk45aTD846T2/uqi7wL6sjxwmYQ3WYK0Wue ScdojHRrhxl3OB9LsoYM4JmFJGoKfl5vEx0XFimSKBuVvgmo45iD+J+2mXjjWq5h OMvTlTqnkefd+iKFck00ahVxUcxJJj9olryCQnl4O7iW05Z9y/bNCeOT0APGRsvK Q0otug5OIIGOJyWDyF3f3suJ+xAgGavDa598iRCD2b9hYHbgNlXJeigmoqHIvRpU /y4XhbURpyx6dRfe1NWzOHnQC8qzs1vAxpiMWnW3zaoyykd3zWU= =Pq77 -----END PGP SIGNATURE----- --OgqxwSJOaUobr8KG--