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 7AAEDC4332F for ; Thu, 10 Mar 2022 16:00:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240631AbiCJQBw (ORCPT ); Thu, 10 Mar 2022 11:01:52 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39542 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240692AbiCJQBb (ORCPT ); Thu, 10 Mar 2022 11:01:31 -0500 Received: from mx07-00178001.pphosted.com (mx08-00178001.pphosted.com [91.207.212.93]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D277F186417; Thu, 10 Mar 2022 08:00:22 -0800 (PST) Received: from pps.filterd (m0046661.ppops.net [127.0.0.1]) by mx07-00178001.pphosted.com (8.16.1.2/8.16.1.2) with ESMTP id 22AARWDr023835; Thu, 10 Mar 2022 16:59:31 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=foss.st.com; h=message-id : date : mime-version : subject : to : cc : references : from : in-reply-to : content-type : content-transfer-encoding; s=selector1; bh=vKPTWN7CzmrHazpB+G2p0y7Va4U2SZ7wiP4CcFo27L4=; b=mbLWETh9lhabuPovfTdTMzMya4arO2yMz1UXhe9GgnCEIWVwahrrAd6XpjR2upEjbrtO IA9he0LvVvqQeB+rE3E3Uyjny8PUlHGSeEu8sxPcnBqSuHTG50r6b8xxNqw3cwyvrJFb xcqGDkXXBvvtF2uZC9gFNOU7O6eoDAKgE0DENaNAHK3Lg0sQ8onyfXu32sikp3p56Gt5 aYo27q4ipsZDOWfkJHbkRn83HHaJpsqO/8iKF+kbPFkTssiADh6JF3PwHayjPwlXMML/ P+t/mK85RMlNYtYb3d78vlel950EFltAg0Qq2OHIE9WRERHJeFpVtqjWHuFbIdD9ZFyv 8Q== Received: from beta.dmz-eu.st.com (beta.dmz-eu.st.com [164.129.1.35]) by mx07-00178001.pphosted.com (PPS) with ESMTPS id 3ekymmt5sg-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 10 Mar 2022 16:59:31 +0100 Received: from euls16034.sgp.st.com (euls16034.sgp.st.com [10.75.44.20]) by beta.dmz-eu.st.com (STMicroelectronics) with ESMTP id C558210002A; Thu, 10 Mar 2022 16:59:29 +0100 (CET) Received: from Webmail-eu.st.com (sfhdag2node2.st.com [10.75.127.5]) by euls16034.sgp.st.com (STMicroelectronics) with ESMTP id B135A2309E5; Thu, 10 Mar 2022 16:59:29 +0100 (CET) Received: from [10.211.5.119] (10.75.127.51) by SFHDAG2NODE2.st.com (10.75.127.5) with Microsoft SMTP Server (TLS) id 15.0.1497.26; Thu, 10 Mar 2022 16:59:28 +0100 Message-ID: Date: Thu, 10 Mar 2022 16:59:28 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Subject: Re: [PATCH 1/3] dt-bindings: mmc: mmci: add a property to disable DMA LLI Content-Language: en-US To: Ulf Hansson CC: Rob Herring , , , , , , Alexandre Torgue , Christophe Kerello , Linus Walleij , Ludovic Barre , Maxime Coquelin , Philipp Zabel , Russell King , Marek Vasut , , Manivannan Sadhasivam , Grzegorz Szymaszek References: <20220304135134.47827-1-yann.gautier@foss.st.com> <20220304135134.47827-2-yann.gautier@foss.st.com> From: Yann Gautier In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.75.127.51] X-ClientProxiedBy: SFHDAG2NODE3.st.com (10.75.127.6) To SFHDAG2NODE2.st.com (10.75.127.5) X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.816,Hydra:6.0.425,FMLib:17.11.64.514 definitions=2022-03-10_06,2022-03-09_01,2022-02-23_01 Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On 3/8/22 11:57, Ulf Hansson wrote: > Hi Yann, > > On Fri, 4 Mar 2022 at 14:52, Yann Gautier wrote: >> >> On STMicroelectronics variant of PL18x, the DMA Linked Lists are supported >> starting from revision v2 of the peripheral. But it has limitations, >> as all the buffers should be aligned on block size (except the last one). >> But this cannot be guaranteed with SDIO. We should then have a property >> to disable the support of LLI. > > Indeed, the buffer handling with SDIO is somewhat special, which also > has been discussed several times on LKML before. In principle, we need > the SDIO func drivers to respect buffer limitations that should be > specified by the mmc host drivers. Quite similar to what we already > have for block devices, like ->max_seg_size, ->max_seg, etc, that is > set per mmc host. > > I realize that implementing something like the above requires bigger > changes, which is why mmc host drivers instead validates the sglists > and the elements. In some cases that means returning an error code and > in others it could mean falling back to a non-DMA based I/O mode. > > For the stm32_sdmmc variant, it looks like the sglist validation is > being managed in sdmmc_idma_validate_data() already. Can it be > extended to cover this case too, rather than using a DT property? > > Kind regards > Uffe Hi Ulf, OK, I'll check what can be done for this. Patches 1 and 2 can be dropped, they will be reworked. But patch 3 of this series could be taken, as not linked to LLI management. Should I push it again alone, or could you review it directly? Best regards, Yann > >> >> Signed-off-by: Yann Gautier >> --- >> Documentation/devicetree/bindings/mmc/arm,pl18x.yaml | 5 +++++ >> 1 file changed, 5 insertions(+) >> >> diff --git a/Documentation/devicetree/bindings/mmc/arm,pl18x.yaml b/Documentation/devicetree/bindings/mmc/arm,pl18x.yaml >> index 1e69a5a42439..309a2c0426e5 100644 >> --- a/Documentation/devicetree/bindings/mmc/arm,pl18x.yaml >> +++ b/Documentation/devicetree/bindings/mmc/arm,pl18x.yaml >> @@ -145,6 +145,11 @@ properties: >> driver to sample the receive data (for example with a voltage switch >> transceiver). >> >> + st,disable-dma-lli: >> + $ref: /schemas/types.yaml#/definitions/flag >> + description: ST Micro-specific property, disable DMA linked lists. >> + It is used for SDIO. >> + >> st,cmd-gpios: >> maxItems: 1 >> description: >> -- >> 2.25.1 >>