From: Herbert Xu Subject: Re: [PATCH 3/3] crypto: Add Allwinner Security System crypto accelerator Date: Wed, 23 Jul 2014 22:13:09 +0800 Message-ID: <20140723141309.GA30324@gondor.apana.org.au> References: <1400771396-9686-1-git-send-email-clabbe.montjoie@gmail.com> <201405241400.03456.marex@denx.de> <20140723135735.GA30132@gondor.apana.org.au> <201407231607.21106.marex@denx.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: LABBE Corentin , 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 To: Marek Vasut Return-path: Received: from helcar.apana.org.au ([209.40.204.226]:59779 "EHLO helcar.apana.org.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752817AbaGWONt (ORCPT ); Wed, 23 Jul 2014 10:13:49 -0400 Content-Disposition: inline In-Reply-To: <201407231607.21106.marex@denx.de> Sender: linux-crypto-owner@vger.kernel.org List-ID: 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? Cheers, -- Email: Herbert Xu Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt