Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752255AbaJQLZH (ORCPT ); Fri, 17 Oct 2014 07:25:07 -0400 Received: from top.free-electrons.com ([176.31.233.9]:47377 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751885AbaJQLZF (ORCPT ); Fri, 17 Oct 2014 07:25:05 -0400 Date: Fri, 17 Oct 2014 13:23:56 +0200 From: Maxime Ripard To: Laurent Pinchart Cc: Dan Williams , Vinod Koul , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, dmaengine@vger.kernel.org, Russell King , Arnd Bergmann , Antoine =?iso-8859-1?Q?T=E9nart?= , Thomas Petazzoni , Alexandre Belloni , Boris Brezillon , Matt Porter , Gregory Clement , Nicolas Ferre Subject: Re: [PATCH v2 2/2] Documentation: dmaengine: Add a documentation for the dma controller API Message-ID: <20141017112356.GO19438@lukather> References: <1411746035-15882-1-git-send-email-maxime.ripard@free-electrons.com> <1411746035-15882-2-git-send-email-maxime.ripard@free-electrons.com> <7725507.nuHj4C7OxF@avalon> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="LQyQLyduEnelPo/g" Content-Disposition: inline In-Reply-To: <7725507.nuHj4C7OxF@avalon> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --LQyQLyduEnelPo/g Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi Laurent, Just getting back on something... On Mon, Oct 06, 2014 at 03:09:48PM +0300, Laurent Pinchart wrote: > > + * device_prep_dma_* > > + - These functions are matching the capabilities you registered > > + previously. > > + - These functions all take the buffer or the scatterlist relevant > > + for the transfer being prepared, and should create a hardware > > + descriptor or a list of descriptors from it > > + - These functions can be called from an interrupt context > > + - Any allocation you might do should be using the GFP_NOWAIT > > + flag, in order not to potentially sleep, but without depleting > > + the emergency pool either. >=20 > You could add "Drivers should try to preallocate the data structures they= =20 > require to prepare a transfer." Isn't that obvious? I mean, if we're in this function, we're already preparing a transfer... And I would expect any programmer that followed CS101 to be able to allocate the memory it needs :) The rest of the issues have been fixed, thanks! Maxime --=20 Maxime Ripard, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com --LQyQLyduEnelPo/g Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJUQPxMAAoJEBx+YmzsjxAga6YP/ie7lFCw3PeiemPMo8VC8h9S lEJ8T/Nm3X5zqh+l80KUJomY2badHndTmwEiKatPqu1Ldw9EAOhFeKhp7Re5tD1/ TWbYDWdptK+5/lplwjekCKbyZ8r9yi8DuHFuAdsk4DDKUMCfiqGOB8+aWi0XUg6f z+UbgMTKFk9xo111s1ApXdyqVKTgNqbLI25w/3JTXc2Ec6qadpgJyLY32kU5q2AU F031Z1URhofFMJ/I/6oat9D4Dk0Iq4c1vi9F0/jzuv/rZy741zS0HAKhyuuHlr2i 6ooh/+mMOQoKK9LiU3IFjjT53yS+TUsc0Au4YYnZHKP5ExCH6q031EtcrptCaNF4 12SyP1z5s9icPp9Pe/UQ09ifqkcoK4OyzJWGMRP5JHB5Bu0LJbZQbYF7ADEShos9 AvM2ZKKyCUYhsqYkNEwJa7yokaufiQjWL882EkByzhvmgcoswRYCw1GAZrlRzTqd 8+7G1IcMAj1YzIKbFbVTe531MlEofGtiYgGQ3xluNS+wYzxdeNuyHwl3bBC2NMi6 FneIQH78tBVsBGKtpPsZyU7YBfNjFeyunjj7WV3UlaqN/ci4wq/GTpIjP/5pjMTp Ewxa/O9R6ZFDjjDW1uyxgjREq/IH0Dg3elP/gWR0axNKhl1XSvSbuI1/kq3H4gU6 pcS+BrDoyX9TbadVVl7f =z4za -----END PGP SIGNATURE----- --LQyQLyduEnelPo/g-- -- 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/