Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752455AbbDPTHk (ORCPT ); Thu, 16 Apr 2015 15:07:40 -0400 Received: from mout.web.de ([212.227.17.12]:58467 "EHLO mout.web.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751160AbbDPTHc convert rfc822-to-8bit (ORCPT ); Thu, 16 Apr 2015 15:07:32 -0400 From: Alexander Stein To: linux-rpi-kernel@lists.infradead.org Cc: Stefan Wahren , Noralf =?ISO-8859-1?Q?Tr=F8nnes?= , dmaengine@vger.kernel.org, vinod.koul@intel.com, dan.j.williams@intel.com, jonathan@raspberrypi.org, linux-kernel@vger.kernel.org Subject: Re: Re: [PATCH] dmaengine: bcm2835: Add slave dma support Date: Thu, 16 Apr 2015 21:06:49 +0200 Message-ID: <8408334.G8cbCZ65GO@kongar> User-Agent: KMail/4.14.6 (Linux/3.18.11-gentoo; KDE/4.14.6; x86_64; ; ) In-Reply-To: <552EB54A.3060404@lategoodbye.de> References: <1429091778-26350-1-git-send-email-noralf@tronnes.org> <552EB54A.3060404@lategoodbye.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8BIT Content-Type: text/plain; charset="utf-8" X-Provags-ID: V03:K0:e0Xd0/XnjbM4VbbT/gzw6bSpfRnOohWmjRtVRVKpGpDHAEAWzrg 3VK2fRaM/cKzUqXHuw8zZQksH4KVgZKPysg5byrBQXGKvVhMYeT5lOA8wud8YpFwe7Stovj mEhrT2knufauNYuAFcP9oxi5IgcDjLF37AjQ+lAkxafXFqghUwWg4YSBD88FO+cOiCCd09Y jGzDFlT2BcXEJix8iT7Xw== X-UI-Out-Filterresults: notjunk:1; Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1182 Lines: 24 Hi Stefan, On Wednesday 15 April 2015, 21:00:26 wrote Stefan Wahren: > Am 15.04.2015 um 11:56 schrieb Noralf Trønnes: > > Add slave transfer capability to BCM2835 dmaengine driver. > > This patch is pulled from the bcm2708-dmaengine driver in the > > Raspberry Pi repo. The work was done by Gellert Weisz. > > > > Tested with the bcm2835-mmc driver from the same repo. > > why not with the upstream kernel? I also looked at slave dma support, especially for use in mmc. It turns our that bcm2835-mmc is written more or less completly new. Mainline linux uses sdhci "framework" which internally uses the SDMA and/or ADMA (both internal, to SD/MMC controller, DMA units) which can be supported by an SDHCI compatible controller. AFAIK the SD/MMC controller in bcm2835 lacks both that is why the driver only uses PIO. I dunno if external DMA usage can so easily be integrated into the sdhci, I have my doubts. Best regards, Alexander -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/