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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 9E720C54EBE for ; Fri, 13 Jan 2023 07:15:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=k42aSRFmdL0IZJDuh3fnGI0grSZjNVc375FSwUxnV5I=; b=eHd82/9F+xr34q 7KfJ5fmks2pvOQkLPYBsZFKOffCvGZ2jLZjPZIpiW/MPY2wU7M09SWZ9CX1NlIofLfCk5kwzbnETV yUARN+lvB/qHYEtWhNGY9w8Vu/vyRryZAhgTc69RxP2G8BCQXOuFRy6cGTpqHpjXDWL7WleWovdbZ ybyz5/sPiHioo4/X7L7BoAgNblu0OFTiy2GCeq1beIrH5okL1mz7XhDBAQTuqGRh8FJs65uMUVzFg LBjCAva7SzWYSJU5LpcI+vY1GOJedivW0rkKhKx43Y0h4vHTIw3mNH98Zdcu9uGY24UTD3h4z/imf pdppS1nGqIy+zAOJkILg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1pGEGq-000wnB-E4; Fri, 13 Jan 2023 07:14:36 +0000 Received: from muru.com ([72.249.23.125]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1pGEGm-000wln-Uo for linux-arm-kernel@lists.infradead.org; Fri, 13 Jan 2023 07:14:34 +0000 Received: from localhost (localhost [127.0.0.1]) by muru.com (Postfix) with ESMTPS id 2210F80FA; Fri, 13 Jan 2023 07:14:32 +0000 (UTC) Date: Fri, 13 Jan 2023 09:14:30 +0200 From: Tony Lindgren To: Arnd Bergmann Cc: Aaro Koskinen , Lukas Bulwahn , Janusz Krzysztofik , Krzysztof Kozlowski , linux-arm-kernel@lists.infradead.org, Linux-OMAP , linux-usb@vger.kernel.org, linux-samsung-soc@vger.kernel.org, kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/4] usb: remove OMAP USB Device Controller and OHCI support for OMAP1/2 chips Message-ID: References: <20230112083746.9551-1-lukas.bulwahn@gmail.com> <20230112083746.9551-4-lukas.bulwahn@gmail.com> <3f2663ff-ff3f-4632-853a-ba4d38df9701@app.fastmail.com> <20230112140524.GK730856@darkstar.musicnaut.iki.fi> <179739a0-5d75-412b-964b-16d5cb6d306d@app.fastmail.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <179739a0-5d75-412b-964b-16d5cb6d306d@app.fastmail.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230112_231433_050633_09AA84DC X-CRM114-Status: GOOD ( 19.17 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org * Arnd Bergmann [230112 14:31]: > On Thu, Jan 12, 2023, at 15:05, Aaro Koskinen wrote: > > On Thu, Jan 12, 2023 at 11:19:53AM +0100, Arnd Bergmann wrote: > >> On Thu, Jan 12, 2023, at 10:53, Tony Lindgren wrote: > >> > >> So if we want to kill off the old DMA stuff there is actually > >> a choice between either making omap_udc PIO-only or converting > >> it to use the standard dmaengine interface. > > > > I use this driver on Palm TE and 770, and without it those boards would > > be useless for my use cases. Also DMA doubles the throughput, probably > > also power usage is smaller. > > Ok, if the performance is important, converting to dmaengine > is probably best. Do you know if this is just a straightforward > replacement of the function calls, or are there technical reasons > why it's not using the dmaengine interface yet? Yes I agree dmaengine is the best solution. Seems like this is the last driver using the old api that never got updated probably because it's not used on the newer SoCs. I don't think there are any technical reasons to not use dmaengine here. FYI, the last blocker for dmaengine use was for drivers using port_window that got added with the drivers/usb/musb/tusb6010_omap.c dmaengine conversion a few years back. Regards, Tony _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel