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 22744ECAAD5 for ; Mon, 29 Aug 2022 14:23:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230374AbiH2OXt (ORCPT ); Mon, 29 Aug 2022 10:23:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47230 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230301AbiH2OXr (ORCPT ); Mon, 29 Aug 2022 10:23:47 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 52CC896FE3 for ; Mon, 29 Aug 2022 07:23:38 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id B9DD760FC1 for ; Mon, 29 Aug 2022 14:23:37 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CE428C433D7; Mon, 29 Aug 2022 14:23:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1661783017; bh=44zwQLhmVAx8XQIP4k+OY6eBr7ArSxuMTxjXKOEzXV4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=StQA3f4H9zV1pyOECNo1hi7KLQrLGd3w+AnrIPaQjg4kw1Qd3gaI0/nxunpTjGLUY sMra3fF3Z2KL7Ntke8L+yieyhAjRBxUn9sFt9DruJajjoV6zZKmkMUXHzlK15gFfSe ljQtVGhR3OXXRfr/aH8sC5OH+QFtdss4q4NwwDZ/dbwlK9vRK4YUV8nVdFU870Cl1h QSaQqQmwtMMLdmBJn75cfLFI3ZcHAg/m5n91mYnqIBbyjYkX6l10Pwh/6OZZk7Ki1s OfRwdekIH11Ik/CjPvGJ1CTo4fbcQ1h2WqEny8apfhWgImsbGLsQ5eLGDZYRGuT6L7 ozeYHMS5to7bQ== Date: Mon, 29 Aug 2022 22:14:23 +0800 From: Jisheng Zhang To: Drew Fustini Cc: Jaehoon Chung , Ulf Hansson , Philipp Zabel , Sebastian Reichel , linux-mmc@vger.kernel.org Subject: Re: Designware MSHC: dw_mmc versus sdhci-of-dwcmshc? Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-mmc@vger.kernel.org On Sat, Aug 27, 2022 at 01:07:16PM -0700, Drew Fustini wrote: > Hello, I am bringing up Linux on an SoC which has Synopsys "DesignWare Hi Drew, > Cores Mobile Storage Host Controller (Cryptographic)" IP configured to > support an eMMC 5.0 device (IS21ES08G) on the bring-up board. I am > trying to figure out why there are two seemingly similar drivers, > dw_mmc and sdhci-of-dwmshc, in drivers/mmc/host for Synopsys > DesignWare host controller IP. I am hoping someone might be able to > give me some insight into the history of these drivers. Generally speaking, dw_mmc isn't sdhci compatible while the sdhci-of-dwmshc is sdhci compatible. Those two are for two different controllers. Regards > > I have found the following: > > - dw_mmc.c is a "DW Multimedia Card Interface driver" > - created back in 2011 with f95f3850f7a9 ("mmc: dw_mmc: Add Synopsys > DesignWare mmc host driver.") > - CONFIG_MMC_DW refers to it as "Synopsys DesignWare Memory Card > Interface" with description of "Synopsys DesignWare Mobile Storage IP > block, this provides host support for SD and MMC interfaces, in both > PIO, internal DMA mode and external DMA mode" > - "snps,dw-mshc" compatible supported in dw_mmc-pltfm.c and > synopsys-dw-mshc.yaml binding refers to it as "Synopsys Designware > Mobile Storage Host Controller" > > - sdhci-of-dwcmshc.c is a "SDHCI platform driver for Synopsys DWC MSHC" > - created more recently in 2018 with e438cf49b305 ("mmc: > sdhci-of-dwcmshc: add SDHCI OF Synopsys DWC MSHC driver") > - CONFIG_MMC_SDHCI_OF_DWCMSHC refers to it as "SDHCI OF support for > the Synopsys DWC MSHC" with description of "Synopsys DesignWare Cores > Mobile Storage Controller support." > - the driver supports "snps,dwcmshc-sdhci" compatible and the > snps,dwcmshc-sdhci.yaml binding describes it as "Synopsys Designware > Mobile Storage Host Controller" > > I would greatly appreciate any advice anyone may have on which driver > might be the best fit. > > Thank you, > Drew