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From: David Brownell <david-b@pacbell.net>
To: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Dan Williams <dan.j.williams@intel.com>,
	linux-kernel@vger.kernel.org,
	Shannon Nelson <shannon.nelson@intel.com>,
	kernel@avr32linux.org, "Francis Moreau" <francis.moro@gmail.com>,
	"Paul Mundt" <lethal@linux-sh.org>,
	"Vladimir A. Barinov" <vbarinov@ru.mvista.com>,
	Pierre Ossman <drzeus-list@drzeus.cx>
Subject: Re: [RFC v2 0/5] dmaengine: Slave DMA interface and example users
Date: Tue, 29 Jan 2008 22:56:14 -0800	[thread overview]
Message-ID: <200801292256.14553.david-b@pacbell.net> (raw)
In-Reply-To: <20080129215453.1e3758ab@siona>

On Tuesday 29 January 2008, Haavard Skinnemoen wrote:
>
> Btw, there's one issue I forgot to mention: I believe the DMA Engine
> framework is currently misusing the DMA mapping API, and this patchset
> makes things worse.
> 
> Currently, the async_tx bits of the API do the required calls to
> dma_map_single() and/or dma_map_page(), but they rely on the driver to
> do the unmapping. This is problematic ...
> 
> How do we solve this?

How about:  for peripheral DMA, don't let the engine see anything
except dma_addr_t values.

The engine needs to be able to dma_alloc_coherent() memory too,
which is pre-mapped.

- Dave

  reply	other threads:[~2008-01-30  7:30 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-01-29 18:10 Haavard Skinnemoen
2008-01-29 18:10 ` [RFC v2 1/5] dmaengine: Add dma_client parameter to device_alloc_chan_resources Haavard Skinnemoen
2008-01-29 18:10   ` [RFC v2 2/5] dmaengine: Add slave DMA interface Haavard Skinnemoen
2008-01-29 18:10     ` [RFC v2 3/5] dmaengine: Make DMA Engine menu visible for AVR32 users Haavard Skinnemoen
2008-01-29 18:10       ` [RFC v2 4/5] dmaengine: Driver for the Synopsys DesignWare DMA controller Haavard Skinnemoen
2008-01-29 18:10         ` [RFC v2 5/5] Atmel MCI: Driver for Atmel on-chip MMC controllers Haavard Skinnemoen
2008-02-13 18:30           ` Pierre Ossman
2008-02-13 18:47             ` Haavard Skinnemoen
2008-02-14 14:00             ` MMC core debugfs support (was Re: [RFC v2 5/5] Atmel MCI: Driver for Atmel on-chip MMC controllers) Haavard Skinnemoen
2008-02-25 17:12               ` Pierre Ossman
2008-02-13 19:11           ` [RFC v2 5/5] Atmel MCI: Driver for Atmel on-chip MMC controllers Dan Williams
2008-02-13 21:06             ` Haavard Skinnemoen
2008-02-13 23:55               ` Dan Williams
2008-02-14  8:36                 ` Haavard Skinnemoen
2008-02-14 18:34                   ` Dan Williams
2008-02-14 19:21                     ` Haavard Skinnemoen
2008-01-30 18:53         ` [RFC v2 4/5] dmaengine: Driver for the Synopsys DesignWare DMA controller Dan Williams
2008-01-30  7:30     ` [RFC v2 2/5] dmaengine: Add slave DMA interface David Brownell
2008-01-30  9:27       ` Haavard Skinnemoen
2008-01-30 10:52         ` David Brownell
2008-01-30 12:26           ` Haavard Skinnemoen
2008-01-31  8:27             ` David Brownell
2008-01-31  8:44               ` Paul Mundt
2008-01-31 12:51                 ` David Brownell
2008-01-31 14:12                   ` Haavard Skinnemoen
2008-01-31 13:52               ` Haavard Skinnemoen
2008-02-06 21:08             ` Dan Williams
2008-02-07 17:56               ` Haavard Skinnemoen
2008-01-30 18:28           ` Dan Williams
2008-01-30 20:45             ` David Brownell
2008-01-31  6:35     ` SDIO driver not receiving responses Farbod Nejati
2008-02-07 19:51       ` Pierre Ossman
2008-01-29 20:54 ` [RFC v2 0/5] dmaengine: Slave DMA interface and example users Haavard Skinnemoen
2008-01-30  6:56   ` David Brownell [this message]
2008-01-30  8:56     ` Haavard Skinnemoen
2008-01-30 17:39       ` Dan Williams
2008-02-04 15:32         ` Haavard Skinnemoen
2008-02-06 18:46           ` Dan Williams
2008-02-07 17:52             ` Haavard Skinnemoen

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