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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 F0E27C2D0DB for ; Fri, 24 Jan 2020 13:14:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B6E7B206D5 for ; Fri, 24 Jan 2020 13:14:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ti.com header.i=@ti.com header.b="b2NNtPZd" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389373AbgAXNON (ORCPT ); Fri, 24 Jan 2020 08:14:13 -0500 Received: from lelv0142.ext.ti.com ([198.47.23.249]:39950 "EHLO lelv0142.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387445AbgAXNON (ORCPT ); Fri, 24 Jan 2020 08:14:13 -0500 Received: from lelv0265.itg.ti.com ([10.180.67.224]) by lelv0142.ext.ti.com (8.15.2/8.15.2) with ESMTP id 00OC4hFK113955; Fri, 24 Jan 2020 06:04:43 -0600 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1579867484; bh=ZiaD4SnCdosS8nQj0oAGF73NcGkqbYROWitRkBVgCU4=; h=Subject:To:CC:References:From:Date:In-Reply-To; b=b2NNtPZdhbz/8dI8KJE8mwbYPflq+53YLKNqNwKLejvpXl5CuIO9xUin33ng/zQIU IOiNYbLMKRbk8RAJhx2jG+cB7ypZFiT5tyBZCj0gga5D4GcJMP0m3OWUVde3dbk3YC 14sCzXFRdKiE44Lzr+EaVBexwcMsuhI9JBngGOWo= Received: from DFLE112.ent.ti.com (dfle112.ent.ti.com [10.64.6.33]) by lelv0265.itg.ti.com (8.15.2/8.15.2) with ESMTPS id 00OC4hd2012138 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Fri, 24 Jan 2020 06:04:43 -0600 Received: from DFLE114.ent.ti.com (10.64.6.35) by DFLE112.ent.ti.com (10.64.6.33) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1847.3; Fri, 24 Jan 2020 06:04:43 -0600 Received: from lelv0326.itg.ti.com (10.180.67.84) by DFLE114.ent.ti.com (10.64.6.35) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1847.3 via Frontend Transport; Fri, 24 Jan 2020 06:04:43 -0600 Received: from [192.168.2.6] (ileax41-snat.itg.ti.com [10.172.224.153]) by lelv0326.itg.ti.com (8.15.2/8.15.2) with ESMTP id 00OC4fPg018694; Fri, 24 Jan 2020 06:04:41 -0600 Subject: Re: [PATCH for-next] arm64: defconfig: Set bcm2835-dma as built-in To: Nicolas Saenz Julienne , Ulf Hansson CC: , Catalin Marinas , , , Will Deacon , References: From: Peter Ujfalusi Message-ID: <86672a12-6b88-dba8-0945-b6321ccf28c3@ti.com> Date: Fri, 24 Jan 2020 14:05:25 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 8bit X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 24/01/2020 13.51, Nicolas Saenz Julienne wrote: > Hi Peter, > > On Fri Jan 24, 2020 at 1:31 PM, Peter Ujfalusi wrote: >> Hi Nicolas, >> >> On 24/01/2020 13.17, Nicolas Saenz Julienne wrote: >>> With the introduction of 738987a1d6f1 ("mmc: bcm2835: Use >>> dma_request_chan() instead dma_request_slave_channel()") sdhost-bcm2835 >>> now waits for its DMA channel to be available when defined in the >>> device-tree (it would previously default to PIO). Albeit the right >>> behaviour, the MMC host is needed for booting. So this makes sure the >>> DMA channel shows up in time. >>> >>> Fixes: 738987a1d6f1 ("mmc: bcm2835: Use dma_request_chan() instead dma_request_slave_channel()") >> >> it is not a bug, it is a feature ;) > > Agree, I'm just afraid of your series being picked up by a stable > release without this patch. But maybe it's not necessary? If you need MMC rootfs then the DMA needs to be built in or have initrd with the modules. The driver expects to have DMA channel and it is going to wait for it to appear unless the request fails. Without moving the DMA as built in and removing the deferred probe handling form the MMC driver, one can just remove the DMA support from the mmc-bcm2835 as it is not used at all. I wonder why this is not signaled by automated boot testing, if any exists for bcm2835. >> Yes, if a driver have DMA binding and it is needed during boot then the >> DMA driver also needs to be built in. >> I believe it is desired to use DMA instead of PIO in any case for MMC >> and in the past bcm2835 did not used DMA if DMA was module and the MMC >> was built in. >> >> Sorry for the inconvenience this change has caused to bcm2835! > > Not at all :) > >> Reviewed-by: Peter Ujfalusi > > Thanks, > Nicolas > - Péter Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki