Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933160AbaGWSwS (ORCPT ); Wed, 23 Jul 2014 14:52:18 -0400 Received: from mail-wg0-f47.google.com ([74.125.82.47]:60887 "EHLO mail-wg0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932887AbaGWSwQ (ORCPT ); Wed, 23 Jul 2014 14:52:16 -0400 Message-ID: <53D0045C.6090605@gmail.com> Date: Wed, 23 Jul 2014 20:52:12 +0200 From: Corentin LABBE User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: Marek Vasut , Herbert Xu CC: robh+dt@kernel.org, pawel.moll@arm.com, mark.rutland@arm.com, ijc+devicetree@hellion.org.uk, galak@codeaurora.org, rdunlap@infradead.org, maxime.ripard@free-electrons.com, linux@arm.linux.org.uk, davem@davemloft.net, grant.likely@linaro.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org Subject: Re: [PATCH 3/3] crypto: Add Allwinner Security System crypto accelerator References: <1400771396-9686-1-git-send-email-clabbe.montjoie@gmail.com> <201407231607.21106.marex@denx.de> <20140723141309.GA30324@gondor.apana.org.au> <201407231751.02050.marex@denx.de> In-Reply-To: <201407231751.02050.marex@denx.de> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Le 23/07/2014 17:51, Marek Vasut a ?crit : > On Wednesday, July 23, 2014 at 04:13:09 PM, Herbert Xu wrote: >> On Wed, Jul 23, 2014 at 04:07:20PM +0200, Marek Vasut wrote: >>> On Wednesday, July 23, 2014 at 03:57:35 PM, Herbert Xu wrote: >>>> On Sat, May 24, 2014 at 02:00:03PM +0200, Marek Vasut wrote: >>>>>> + } >>>>>> +#endif >>>>>> + >>>>>> +#ifdef CONFIG_CRYPTO_DEV_SUNXI_SS_MD5 >>>>>> + err = crypto_register_shash(&sunxi_md5_alg); >>>>> >>>>> Do not use shash for such device. This is clearly and ahash (and >>>>> async in general) device. The rule of a thumb here is that you use >>>>> sync algos only for devices which have dedicated instructions for >>>>> computing the transformation. For devices which are attached to some >>>>> kind of bus, you use async algos (ahash etc). >>>> >>>> I'm sorry that I didn't catch this earlier but there is no such >>>> rule. >>>> >>>> Unless you need the async interface you should stick to the sync >>>> interfaces for the sake of simplicity. >>>> >>>> We have a number of existing drivers that are synchronous but >>>> using the async interface. They should either be converted >>>> over to the sync interface or made interrupt-driven if possible. >>> >>> Sure, but this device is interrupt driven and uses DMA to feed the crypto >>> engine, therefore async, right ? >> >> If it's interrupt-driven, then yes it would certainly make sense to >> be async. But all I see is polling in the latest posting, was the >> first version different? > > I stand corrected then, sorry. > > Is it possible to use DMA to feed the crypto accelerator, Corentin? > > Best regards, > Marek Vasut > Yes, DMA is possible and will be implemented soon. So if I have well understood, I keep using async interface. -- 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/