From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933601AbbENSkJ (ORCPT ); Thu, 14 May 2015 14:40:09 -0400 Received: from down.free-electrons.com ([37.187.137.238]:39370 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932807AbbENSkG (ORCPT ); Thu, 14 May 2015 14:40:06 -0400 Date: Thu, 14 May 2015 20:38:53 +0200 From: Maxime Ripard To: Robert Jarzmik Cc: Vinod Koul , Jonathan Corbet , Daniel Mack , Haojian Zhuang , dmaengine@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v3 6/6] Documentation: dmaengine: document DMA_CTRL_ACK Message-ID: <20150514183853.GN4004@lukather> References: <1431626006-1708-1-git-send-email-robert.jarzmik@free.fr> <1431626006-1708-6-git-send-email-robert.jarzmik@free.fr> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="Vxa5joy26gVGOrvU" Content-Disposition: inline In-Reply-To: <1431626006-1708-6-git-send-email-robert.jarzmik@free.fr> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --Vxa5joy26gVGOrvU Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi Robert, On Thu, May 14, 2015 at 07:53:26PM +0200, Robert Jarzmik wrote: > Add documentation about acking the transfers, and their > reusability. >=20 > Signed-off-by: Robert Jarzmik > --- > Documentation/dmaengine/provider.txt | 11 ++++++----- > 1 file changed, 6 insertions(+), 5 deletions(-) >=20 > diff --git a/Documentation/dmaengine/provider.txt b/Documentation/dmaengi= ne/provider.txt > index 05d2280..33a81ce 100644 > --- a/Documentation/dmaengine/provider.txt > +++ b/Documentation/dmaengine/provider.txt > @@ -345,11 +345,12 @@ where to put them) > that abstracts it away. > =20 > * DMA_CTRL_ACK > - - Undocumented feature > - - No one really has an idea of what it's about, besides being > - related to reusing the DMA transaction descriptors or having > - additional transactions added to it in the async-tx API > - - Useless in the case of the slave API > + - if set, the TX transfer can be reused after being completed. Your sentences should start with an upper-case letter. > + - there is a guarantee the TX won't be freed until it is acked > + by async_tx_ack() We never talked about what a "TX transfer" is in the documentation. That should be documented. > + - as a consequence, if a device driver wants to skip the dma_map_sg(= ) and > + dma_unmap_sg() because the DMA'd data wasn't used, it can resubmit= the > + transfer right after its completion. =46rom a provider PoV, the data should always be mapped and / or allocated in coherent way, so I'm not sure how does that's relevant in the provider doc. Also, we should still mention that it's !slave API only. Maxime --=20 Maxime Ripard, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com --Vxa5joy26gVGOrvU Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJVVOu9AAoJEBx+YmzsjxAgeroP/R1g4Cv3WdZl5it1MX5jNt9P MwGmc69qlzHWj9nAl70Uuq72X1osA0nro6GILxPcwgCKcs+X+3nGJHhbzHOi6m0p +sA8t8QEB68UTAR3cEL8WkegfKfWZanqExMDA4GMhJhJlGiq6YGZxoV9xwywNJlL EQ6RbEgLuZpqcmeqg5QDrdi6275JIAFZI3saYNOvrum6IoQhDheaqnMz4F+CQTmW nNgllzfMqySbtif1lHaISdIHn8hLjX+PvBonJx9jqU7BhVXsQ9Z73jurQk0730mR YaxFEDOZqqW7xTsssaRXgzT3QLwjv0T33NZxtmMaiY4I/lDc1FBuvSbqct+9Gu/z 2NpEzldMKqfaIwqldwU7xP5xkkpw159BoMNjVxACrWITe6FRRaCw3+vBLNmV+Y6M P5AiRBf6UvAYLVbJD88fbK5EpcB/su9GXx5fHhwEtCECBPnpZaukj5rFS18+LcAO 8N7ijPTTMIBXpWhfcxQFmb1xVioCe7HyLgWN1GGcx+cQJ6QxJ5oESWr4otVfcdgV g/et047pbVpxbqmrFimDIDoMttf3K/PIzSobWs/EwpHkAEjAQzc8lknUOOaIUd8s IxPrwvou0uPRpwfZkZhztRFC8RSx5a6nV3g0g2bkEt3iVJE32LCged6biB/nHHeM I1BOavfvfKdHqvwl7dwh =hG1x -----END PGP SIGNATURE----- --Vxa5joy26gVGOrvU--