From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751449AbaHaNFd (ORCPT ); Sun, 31 Aug 2014 09:05:33 -0400 Received: from mezzanine.sirena.org.uk ([106.187.55.193]:43116 "EHLO mezzanine.sirena.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751097AbaHaNFc (ORCPT ); Sun, 31 Aug 2014 09:05:32 -0400 Date: Sun, 31 Aug 2014 14:05:16 +0100 From: Mark Brown To: Geert Uytterhoeven Cc: linux-spi , "linux-kernel@vger.kernel.org" Message-ID: <20140831130516.GH29327@sirena.org.uk> References: <1409328631-1420-1-git-send-email-geert@linux-m68k.org> <20140829173752.GX29327@sirena.org.uk> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="NncV4Eud7lVzK4Rv" Content-Disposition: inline In-Reply-To: X-Cookie: Simulated picture. User-Agent: Mutt/1.5.23 (2014-03-12) X-SA-Exim-Connect-IP: 94.175.94.161 X-SA-Exim-Mail-From: broonie@sirena.org.uk Subject: Re: [PATCH v2] spi/drivers: Restrict COMPILE_TEST by HAS_DMA where needed 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 --NncV4Eud7lVzK4Rv Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Sun, Aug 31, 2014 at 10:39:09AM +0200, Geert Uytterhoeven wrote: > On Fri, Aug 29, 2014 at 9:13 PM, Geert Uytterhoeven > >> I'm wondering if it isn't better to have the non-DMA platforms define > >> stub (always error) DMA functions instead - it's less error prone and > >> with SPI there's a bunch of drivers which can run perfectly usefully > >> without DMA while optionally supporting DMA. > > The SPI problem will sort itself out once all SPI master drivers have been > > converted to use the SPI DMA core ;-) > BTW, the dmaengine API has stubs, only the low-level dma-mapping API > doesn't. That's why e.g. spi-rspi doesn't need a dependency on HAS_DMA. > So it's indeed a good thing to handle the low-level DMA mapping in the > subsystem's core, as only that part can be optional and depend on HAS_DMA. Yeah, but I'd expect there's other subsystems which will be in a similar boat here and with dmaengine having stubs it seems strange that the mapping API doesn't. --NncV4Eud7lVzK4Rv Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBAgAGBQJUAx2JAAoJELSic+t+oim9rc0P/i7Dm0TqbBvt2WbfUyImsHoo WyUNTqyw3WacLp/zIR+4Ya5OvnceOI7QRCx+96wFo92zc8dp98OENoOaFdKm6tPy 4yj8oa58X/Fx53xtjY8IbjEwwi8s3yqTR/4RwgLlV0funP5r2bZs6WX3gCq42Y+m fE8LA6GffXQGgRY56VR/G/eGbQ0LEkhzIZBNBzDgvYtyf9aN+Jrja4t1oIp0m3q7 O5T/Fhps6mav/TUJxSZLwopp+RqflrFPeXdt/5QKmKkpUt3pNkqXBtAR80UkyfHd Oij+MmGVOTKyHl3lR+29w7L6bTqT1u5zcnTSTOeMGsHlcVwfph5wnjLqnics9pLJ ErtnDungvFYfoixdf5IIW/swBjorBZaYnfWqKq1EK3qQvDFMiR+e3dBWDRmD8jPY +dcJq6cV/WYoOdXZTXL44pO6BKDKOnX3tJwTY9BpfFSpb9V/2wMtQcGFFo1Cm+16 4AWZLQhYKavTmUbPKzPFi/1QlKeU99hVCur2O5Hp/1yIErWthi8QTXTaVf73rZIb yUs1u6YZ+hFearGCyHMNae7liwuPzvr2F1jeIvx88O5bU6Y6jIRt25M5qBG2u3Im sUjhxORArsgnKtLE3wRF6uzCYecM12XcHlYZeApRUYgzfNERspu5Hvxs1z2OaY8t XO/6Bj3TP7t8ZqstGzrA =R0s/ -----END PGP SIGNATURE----- --NncV4Eud7lVzK4Rv--