From: Arnd Bergmann <arnd-r2nGTMty4D4@public.gmane.org>
To: Hiroshi Doyu <hdoyu-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
Cc: Joerg Roedel <joerg.roedel-5C7GfCeVMHo@public.gmane.org>,
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Subject: Re: [RFC 0/5] ARM: dma-mapping: New dma_map_ops to control IOVA more precisely
Date: Wed, 19 Sep 2012 07:59:45 +0000 [thread overview]
Message-ID: <201209190759.46174.arnd@arndb.de> (raw)
In-Reply-To: <20120919095843.d1db155e0f085f4fcf64ea32-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
On Wednesday 19 September 2012, Hiroshi Doyu wrote:
> I guess that it would work. Originally I thought that using DMA-API
> and IOMMU-API together in driver might be kind of layering violation
> since IOMMU-API itself is used in DMA-API. Only DMA-API used in driver
> might be cleaner. Considering that DMA API traditionally handling
> anonymous {bus,iova} address only, introducing the concept of
> specific address in DMA API may not be so encouraged, though.
>
> It would be nice to listen how other SoCs have solved similar needs.
In general, I would recommend using only the IOMMU API when you have a device
driver that needs to control the bus virtual address space and that manages
a device that resides in its own IOMMU context. I would recommend using
only the dma-mapping API when you have a device that lives in a shared
bus virtual address space with other devices, and then never ask for
a specific bus virtual address.
Can you explain what devices you see that don't fit in one of those two
categories?
Arnd
next prev parent reply other threads:[~2012-09-19 7:59 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-29 6:55 [RFC 0/5] ARM: dma-mapping: New dma_map_ops to control IOVA more precisely Hiroshi Doyu
2012-08-29 6:55 ` [RFC 1/5] ARM: dma-mapping: New dma_map_ops->iova_get_free_{total,max} functions Hiroshi Doyu
[not found] ` <1346223335-31455-1-git-send-email-hdoyu-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
2012-08-29 6:55 ` [RFC 2/5] ARM: dma-mapping: New dma_map_ops->iova_{alloc, free}() functions Hiroshi Doyu
2012-08-29 6:55 ` [RFC 5/5] ARM: dma-mapping: Introduce dma_map_linear_attrs() for IOVA linear map Hiroshi Doyu
2012-09-18 12:49 ` [RFC 0/5] ARM: dma-mapping: New dma_map_ops to control IOVA more precisely Joerg Roedel
2012-09-19 6:58 ` Hiroshi Doyu
[not found] ` <20120919095843.d1db155e0f085f4fcf64ea32-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
2012-09-19 7:59 ` Arnd Bergmann [this message]
[not found] ` <201209190759.46174.arnd-r2nGTMty4D4@public.gmane.org>
2012-09-19 11:41 ` Hiroshi Doyu
2012-09-19 12:50 ` Joerg Roedel
[not found] ` <20120919125020.GQ2505-5C7GfCeVMHo@public.gmane.org>
2012-09-20 1:44 ` Krishna Reddy
[not found] ` <401E54CE964CD94BAE1EB4A729C7087E379FDC1EEB-wAPRp6hVlRhDw2glCA4ptUEOCMrvLtNR@public.gmane.org>
2012-09-20 2:21 ` Stephen Warren
[not found] ` <505A7DB4.4090902-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>
2012-09-20 6:40 ` Krishna Reddy
[not found] ` <401E54CE964CD94BAE1EB4A729C7087E379FDC1F2D-wAPRp6hVlRhDw2glCA4ptUEOCMrvLtNR@public.gmane.org>
2012-09-20 15:27 ` Stephen Warren
[not found] ` <505B35F7.2080201-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>
2012-09-21 18:16 ` Krishna Reddy
2012-09-24 9:04 ` How to specify IOMMU'able devices in DT (was: [RFC 0/5] ARM: dma-mapping: New dma_map_ops to control IOVA more precisely) Hiroshi Doyu
2012-09-24 9:28 ` James Bottomley
2012-09-24 9:44 ` Hiroshi Doyu
[not found] ` <20120924124452.41070ed2ee9944d930cffffc-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
2012-09-24 11:14 ` Marek Szyprowski
2012-09-24 11:50 ` How to specify IOMMU'able devices in DT Hiroshi Doyu
[not found] ` <20120924.145014.1452596970914043018.hdoyu-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
2012-11-28 13:48 ` [PATCH 1/1] ARM: tegra: bus_notifier registers IOMMU devices(was: How to specify IOMMU'able devices in DT) Hiroshi Doyu
[not found] ` <20121128.154832.539666140149950229.hdoyu-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
2012-11-28 18:07 ` Stephen Warren
2012-11-29 6:45 ` Hiroshi Doyu
2012-11-29 10:17 ` Thierry Reding
2012-11-30 4:59 ` Mark Zhang
2012-11-30 8:06 ` [PATCH 1/1] ARM: tegra: bus_notifier registers IOMMU devices Hiroshi Doyu
2012-08-29 6:55 ` [RFC 3/5] ARM: dma-mapping: New dma_map_ops->iova_alloc*_at* function Hiroshi Doyu
2012-08-29 6:55 ` [RFC 4/5] ARM: dma-mapping: New dma_map_ops->map_page*_at* function Hiroshi Doyu
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