From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752117AbaJPQPd (ORCPT ); Thu, 16 Oct 2014 12:15:33 -0400 Received: from galahad.ideasonboard.com ([185.26.127.97]:37143 "EHLO galahad.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751641AbaJPQPb (ORCPT ); Thu, 16 Oct 2014 12:15:31 -0400 From: Laurent Pinchart To: Maxime Ripard Cc: dmaengine@vger.kernel.org, Vinod Koul , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Antoine =?ISO-8859-1?Q?T=E9nart?= , lars@metafoo.de, Russell King , Dan Williams Subject: Re: [PATCH v2 06/53] dmaengine: Create a generic dma_slave_caps callback Date: Thu, 16 Oct 2014 19:15:40 +0300 Message-ID: <1496298.0f0GAuhKve@avalon> User-Agent: KMail/4.12.5 (Linux/3.14.14-gentoo; KDE/4.12.5; x86_64; ; ) In-Reply-To: <1413454672-27400-7-git-send-email-maxime.ripard@free-electrons.com> References: <1413454672-27400-1-git-send-email-maxime.ripard@free-electrons.com> <1413454672-27400-7-git-send-email-maxime.ripard@free-electrons.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Maxime, Thank you for the patch. On Thursday 16 October 2014 12:17:05 Maxime Ripard wrote: > dma_slave_caps is very important to the generic layers that might interact > with dmaengine, such as ASoC. Unfortunately, it has been added as yet > another dma_device callback, and most of the existing drivers haven't > implemented it, reducing its reliability. > > Introduce a generic behaviour and a flag to trigger it. In case this flag > hasn't been set, fall back to the old mechanism. > > Signed-off-by: Maxime Ripard > --- > include/linux/dmaengine.h | 25 +++++++++++++++++++++---- > 1 file changed, 21 insertions(+), 4 deletions(-) > > diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h > index 4d0294ec3567..85afd71df2e7 100644 > --- a/include/linux/dmaengine.h > +++ b/include/linux/dmaengine.h > @@ -643,6 +643,8 @@ struct dma_device { > int dev_id; > struct device *dev; > > + bool generic_slave_caps; > + > int (*device_alloc_chan_resources)(struct dma_chan *chan); > void (*device_free_chan_resources)(struct dma_chan *chan); > > @@ -772,17 +774,32 @@ static inline struct dma_async_tx_descriptor > *dmaengine_prep_interleaved_dma( > > static inline int dma_get_slave_caps(struct dma_chan *chan, struct > dma_slave_caps *caps) { This is getting too big for an inline function, it should be moved to drivers/dma/dmaengine.c. > + struct dma_device *device; > + > if (!chan || !caps) > return -EINVAL; > > + device = chan->device; > + > /* check if the channel supports slave transactions */ > - if (!test_bit(DMA_SLAVE, chan->device->cap_mask.bits)) > + if (!test_bit(DMA_SLAVE, device->cap_mask.bits)) > + return -ENXIO; > + > + if (device->device_slave_caps) > + return device->device_slave_caps(chan, caps); > + > + /* > + * Check whether it reports it uses the generic slave > + * capabilities, if not, that means it doesn't support any > + * kind of slave capabilities reporting. > + */ > + if (device->generic_slave_caps) > return -ENXIO; Couldn't we replace that check with if (device->device_control) and get rid of the generic_slave_caps field ? Drivers converted to the new API would then get slave caps support for free. > - if (chan->device->device_slave_caps) > - return chan->device->device_slave_caps(chan, caps); > + caps->cmd_pause = !!device->device_pause; > + caps->cmd_terminate = !!device->device_terminate_all; > > - return -ENXIO; > + return 0; > } > > static inline int dmaengine_terminate_all(struct dma_chan *chan) -- Regards, Laurent Pinchart