From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161336AbcFBO1S (ORCPT ); Thu, 2 Jun 2016 10:27:18 -0400 Received: from mezzanine.sirena.org.uk ([106.187.55.193]:35326 "EHLO mezzanine.sirena.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161137AbcFBO1O (ORCPT ); Thu, 2 Jun 2016 10:27:14 -0400 Date: Thu, 2 Jun 2016 15:26:49 +0100 From: Mark Brown To: Michal Suchanek Cc: Priit Laes , Maxime Ripard , Geert Uytterhoeven , linux-sunxi , Chen-Yu Tsai , linux-spi , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" Message-ID: <20160602142649.GJ2282@sirena.org.uk> References: <20160530112610.GJ29837@sirena.org.uk> <20160530150343.GL29837@sirena.org.uk> <20160530155016.GO29837@sirena.org.uk> <20160601180056.GA4908@lukather> <1464842546.23881.3.camel@plaes.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="Ublo+h3cBgJ33ahC" Content-Disposition: inline In-Reply-To: X-Cookie: Your present plans will be successful. User-Agent: Mutt/1.6.0 (2016-04-01) X-SA-Exim-Connect-IP: 92.54.156.156 X-SA-Exim-Mail-From: broonie@sirena.org.uk Subject: Re: [linux-sunxi] Re: [PATCH 5/5] RFC spi: sun4i: add DMA support X-SA-Exim-Version: 4.2.1 (built Mon, 26 Dec 2011 16:24:06 +0000) X-SA-Exim-Scanned: Yes (on mezzanine.sirena.org.uk) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --Ublo+h3cBgJ33ahC Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Thu, Jun 02, 2016 at 02:14:26PM +0200, Michal Suchanek wrote: > On 2 June 2016 at 06:42, Priit Laes wrote: > > On Wed, 2016-06-01 at 20:00 +0200, Maxime Ripard wrote: > > Actually it non-DMA case works fine if you don't need SPI transfers > > larger than SUN4I_FIFO_DEPTH - 1, which is 63 bytes. > > This was addressed by this patch, but was never applied: > > http://permalink.gmane.org/gmane.linux.kernel.spi.devel/18950 > And the code added in that patch will never run unless you > 1) use long spi transfers > 2) compile in/load SPI without DMA support > There is no reason for doing 2) since we have do DMA support for sunxi. Well, presumably such code exists and is being worked on? > So that's another code path that needs maintenance and testing and > likely will not get it. Oh, come on. You might not want to use it yourself but the chances are that someone will want to use it just like the situation with all the other SPI drivers. It's a perfectly reasonable and sensible feature to support upstream. I really do not understand why there is such a strong desire to have these devices be a special snowflake here, the worst that's likely to happen here is that you're going to end up having to either remove the DMA controller from the DT or load the driver for it neither of which seem like the end of the world. --Ublo+h3cBgJ33ahC Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQEcBAEBCAAGBQJXUEIoAAoJECTWi3JdVIfQoXgH/0kJrQUcjqkyzqBingUGHrIh smPpTppZgcd/dvouu7TgEy+afmhxX2N3RsrN9+FL+HQlTB5DVSBfWMkpjNRUgTv2 eKR90n09RbdYPXo7vp2S6AaeuG1+voIHuxHNAuq9Ihu7w3ZaM34gyaDxx3KpibK1 KyWxs5qRttt/jn7UswzeUgb/8fHqyWXGnsEwHkuhlleSfCBViaURisB6MefnlhD6 DcRgiLnm5RFgJ12DjUqQmH9SOyQjOTVfzfibbXqsErjwqhVPp/NXTTtigTSAU+hV 5nklA2meLgSrtANxVWaoDtKMOrFmvBY3K+KmsFQI0uSEOq2AK0QEHfR6vIQceIk= =3X6L -----END PGP SIGNATURE----- --Ublo+h3cBgJ33ahC--