From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752887AbbFCGOW (ORCPT ); Wed, 3 Jun 2015 02:14:22 -0400 Received: from lb1-smtp-cloud6.xs4all.net ([194.109.24.24]:35003 "EHLO lb1-smtp-cloud6.xs4all.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751042AbbFCGOP (ORCPT ); Wed, 3 Jun 2015 02:14:15 -0400 Message-ID: <556E9B27.20006@xs4all.nl> Date: Wed, 03 Jun 2015 08:13:59 +0200 From: Hans Verkuil User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Icedove/31.6.0 MIME-Version: 1.0 To: Sumit Semwal , linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org CC: linaro-kernel@lists.linaro.org, stanislawski.tomasz@googlemail.com, robdclark@gmail.com, daniel@ffwll.ch, robin.murphy@arm.com Subject: Re: [Linaro-mm-sig] [RFCv3 1/2] device: add dma_params->max_segment_count References: <1422347154-15258-1-git-send-email-sumit.semwal@linaro.org> In-Reply-To: <1422347154-15258-1-git-send-email-sumit.semwal@linaro.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Sumit, Rob, Is there any reason why this patch hasn't been merged yet? It makes perfect sense to me and I would really like to use this in the media drivers. Many DMA engines do have a limit to the number of segments (obviously a max count of 1 being the most common limitation, but other limits are definitely possible), so this patch seems a no-brainer to me. So: Acked-by: Hans Verkuil Regards, Hans On 01/27/2015 09:25 AM, Sumit Semwal wrote: > From: Rob Clark > > For devices which have constraints about maximum number of segments in > an sglist. For example, a device which could only deal with contiguous > buffers would set max_segment_count to 1. > > The initial motivation is for devices sharing buffers via dma-buf, > to allow the buffer exporter to know the constraints of other > devices which have attached to the buffer. The dma_mask and fields > in 'struct device_dma_parameters' tell the exporter everything else > that is needed, except whether the importer has constraints about > maximum number of segments. > > Signed-off-by: Rob Clark > [sumits: Minor updates wrt comments] > Signed-off-by: Sumit Semwal > --- > > v3: include Robin Murphy's fix[1] for handling '0' as a value for > max_segment_count > v2: minor updates wrt comments on the first version > > [1]: http://article.gmane.org/gmane.linux.kernel.iommu/8175/ > > include/linux/device.h | 1 + > include/linux/dma-mapping.h | 19 +++++++++++++++++++ > 2 files changed, 20 insertions(+) > > diff --git a/include/linux/device.h b/include/linux/device.h > index fb506738f7b7..a32f9b67315c 100644 > --- a/include/linux/device.h > +++ b/include/linux/device.h > @@ -647,6 +647,7 @@ struct device_dma_parameters { > * sg limitations. > */ > unsigned int max_segment_size; > + unsigned int max_segment_count; /* INT_MAX for unlimited */ > unsigned long segment_boundary_mask; > }; > > diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h > index c3007cb4bfa6..d3351a36d5ec 100644 > --- a/include/linux/dma-mapping.h > +++ b/include/linux/dma-mapping.h > @@ -154,6 +154,25 @@ static inline unsigned int dma_set_max_seg_size(struct device *dev, > return -EIO; > } > > +#define DMA_SEGMENTS_MAX_SEG_COUNT ((unsigned int) INT_MAX) > + > +static inline unsigned int dma_get_max_seg_count(struct device *dev) > +{ > + if (dev->dma_parms && dev->dma_parms->max_segment_count) > + return dev->dma_parms->max_segment_count; > + return DMA_SEGMENTS_MAX_SEG_COUNT; > +} > + > +static inline int dma_set_max_seg_count(struct device *dev, > + unsigned int count) > +{ > + if (dev->dma_parms) { > + dev->dma_parms->max_segment_count = count; > + return 0; > + } > + return -EIO; > +} > + > static inline unsigned long dma_get_seg_boundary(struct device *dev) > { > return dev->dma_parms ? > From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f174.google.com (mail-wi0-f174.google.com [209.85.212.174]) by kanga.kvack.org (Postfix) with ESMTP id 4EC9C900016 for ; Wed, 3 Jun 2015 02:14:16 -0400 (EDT) Received: by wiga1 with SMTP id a1so2054136wig.0 for ; Tue, 02 Jun 2015 23:14:15 -0700 (PDT) Received: from lb1-smtp-cloud6.xs4all.net (lb1-smtp-cloud6.xs4all.net. [194.109.24.24]) by mx.google.com with ESMTPS id fa9si8012wid.33.2015.06.02.23.14.13 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Tue, 02 Jun 2015 23:14:14 -0700 (PDT) Message-ID: <556E9B27.20006@xs4all.nl> Date: Wed, 03 Jun 2015 08:13:59 +0200 From: Hans Verkuil MIME-Version: 1.0 Subject: Re: [Linaro-mm-sig] [RFCv3 1/2] device: add dma_params->max_segment_count References: <1422347154-15258-1-git-send-email-sumit.semwal@linaro.org> In-Reply-To: <1422347154-15258-1-git-send-email-sumit.semwal@linaro.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Sumit Semwal , linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org Cc: linaro-kernel@lists.linaro.org, stanislawski.tomasz@googlemail.com, robdclark@gmail.com, daniel@ffwll.ch, robin.murphy@arm.com Hi Sumit, Rob, Is there any reason why this patch hasn't been merged yet? It makes perfect sense to me and I would really like to use this in the media drivers. Many DMA engines do have a limit to the number of segments (obviously a max count of 1 being the most common limitation, but other limits are definitely possible), so this patch seems a no-brainer to me. So: Acked-by: Hans Verkuil Regards, Hans On 01/27/2015 09:25 AM, Sumit Semwal wrote: > From: Rob Clark > > For devices which have constraints about maximum number of segments in > an sglist. For example, a device which could only deal with contiguous > buffers would set max_segment_count to 1. > > The initial motivation is for devices sharing buffers via dma-buf, > to allow the buffer exporter to know the constraints of other > devices which have attached to the buffer. The dma_mask and fields > in 'struct device_dma_parameters' tell the exporter everything else > that is needed, except whether the importer has constraints about > maximum number of segments. > > Signed-off-by: Rob Clark > [sumits: Minor updates wrt comments] > Signed-off-by: Sumit Semwal > --- > > v3: include Robin Murphy's fix[1] for handling '0' as a value for > max_segment_count > v2: minor updates wrt comments on the first version > > [1]: http://article.gmane.org/gmane.linux.kernel.iommu/8175/ > > include/linux/device.h | 1 + > include/linux/dma-mapping.h | 19 +++++++++++++++++++ > 2 files changed, 20 insertions(+) > > diff --git a/include/linux/device.h b/include/linux/device.h > index fb506738f7b7..a32f9b67315c 100644 > --- a/include/linux/device.h > +++ b/include/linux/device.h > @@ -647,6 +647,7 @@ struct device_dma_parameters { > * sg limitations. > */ > unsigned int max_segment_size; > + unsigned int max_segment_count; /* INT_MAX for unlimited */ > unsigned long segment_boundary_mask; > }; > > diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h > index c3007cb4bfa6..d3351a36d5ec 100644 > --- a/include/linux/dma-mapping.h > +++ b/include/linux/dma-mapping.h > @@ -154,6 +154,25 @@ static inline unsigned int dma_set_max_seg_size(struct device *dev, > return -EIO; > } > > +#define DMA_SEGMENTS_MAX_SEG_COUNT ((unsigned int) INT_MAX) > + > +static inline unsigned int dma_get_max_seg_count(struct device *dev) > +{ > + if (dev->dma_parms && dev->dma_parms->max_segment_count) > + return dev->dma_parms->max_segment_count; > + return DMA_SEGMENTS_MAX_SEG_COUNT; > +} > + > +static inline int dma_set_max_seg_count(struct device *dev, > + unsigned int count) > +{ > + if (dev->dma_parms) { > + dev->dma_parms->max_segment_count = count; > + return 0; > + } > + return -EIO; > +} > + > static inline unsigned long dma_get_seg_boundary(struct device *dev) > { > return dev->dma_parms ? > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org From mboxrd@z Thu Jan 1 00:00:00 1970 From: hverkuil@xs4all.nl (Hans Verkuil) Date: Wed, 03 Jun 2015 08:13:59 +0200 Subject: [Linaro-mm-sig] [RFCv3 1/2] device: add dma_params->max_segment_count In-Reply-To: <1422347154-15258-1-git-send-email-sumit.semwal@linaro.org> References: <1422347154-15258-1-git-send-email-sumit.semwal@linaro.org> Message-ID: <556E9B27.20006@xs4all.nl> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Sumit, Rob, Is there any reason why this patch hasn't been merged yet? It makes perfect sense to me and I would really like to use this in the media drivers. Many DMA engines do have a limit to the number of segments (obviously a max count of 1 being the most common limitation, but other limits are definitely possible), so this patch seems a no-brainer to me. So: Acked-by: Hans Verkuil Regards, Hans On 01/27/2015 09:25 AM, Sumit Semwal wrote: > From: Rob Clark > > For devices which have constraints about maximum number of segments in > an sglist. For example, a device which could only deal with contiguous > buffers would set max_segment_count to 1. > > The initial motivation is for devices sharing buffers via dma-buf, > to allow the buffer exporter to know the constraints of other > devices which have attached to the buffer. The dma_mask and fields > in 'struct device_dma_parameters' tell the exporter everything else > that is needed, except whether the importer has constraints about > maximum number of segments. > > Signed-off-by: Rob Clark > [sumits: Minor updates wrt comments] > Signed-off-by: Sumit Semwal > --- > > v3: include Robin Murphy's fix[1] for handling '0' as a value for > max_segment_count > v2: minor updates wrt comments on the first version > > [1]: http://article.gmane.org/gmane.linux.kernel.iommu/8175/ > > include/linux/device.h | 1 + > include/linux/dma-mapping.h | 19 +++++++++++++++++++ > 2 files changed, 20 insertions(+) > > diff --git a/include/linux/device.h b/include/linux/device.h > index fb506738f7b7..a32f9b67315c 100644 > --- a/include/linux/device.h > +++ b/include/linux/device.h > @@ -647,6 +647,7 @@ struct device_dma_parameters { > * sg limitations. > */ > unsigned int max_segment_size; > + unsigned int max_segment_count; /* INT_MAX for unlimited */ > unsigned long segment_boundary_mask; > }; > > diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h > index c3007cb4bfa6..d3351a36d5ec 100644 > --- a/include/linux/dma-mapping.h > +++ b/include/linux/dma-mapping.h > @@ -154,6 +154,25 @@ static inline unsigned int dma_set_max_seg_size(struct device *dev, > return -EIO; > } > > +#define DMA_SEGMENTS_MAX_SEG_COUNT ((unsigned int) INT_MAX) > + > +static inline unsigned int dma_get_max_seg_count(struct device *dev) > +{ > + if (dev->dma_parms && dev->dma_parms->max_segment_count) > + return dev->dma_parms->max_segment_count; > + return DMA_SEGMENTS_MAX_SEG_COUNT; > +} > + > +static inline int dma_set_max_seg_count(struct device *dev, > + unsigned int count) > +{ > + if (dev->dma_parms) { > + dev->dma_parms->max_segment_count = count; > + return 0; > + } > + return -EIO; > +} > + > static inline unsigned long dma_get_seg_boundary(struct device *dev) > { > return dev->dma_parms ? >