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From: Clemens Ladisch <clemens@ladisch.de>
To: Karl Beldan <karl.beldan@gmail.com>
Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: About dma_sync_single_for_{cpu,device}
Date: Tue, 31 Jul 2012 08:59:21 +0200	[thread overview]
Message-ID: <50178249.7090306@ladisch.de> (raw)
In-Reply-To: <20120731064557.GA4676@gobelin>

Karl Beldan wrote:
> To tx a chunk of data from the SoC => network device, we :
> - prepare a buffer with a leading header embedding a pattern,
> - trigger the xfer and wait for an irq
> // The device updates the pattern and then triggers an irq
> - upon irq we check the pattern for the xfer completion
>
> I was expecting the following to work:
> 	addr = dma_map_single(dev, buffer, size, DMA_TO_DEVICE);

Of both the CPU and the device write to the buffer, you must use
DMA_BIDIRECTIONAL.


Regards,
Clemens

  reply	other threads:[~2012-07-31  7:01 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-07-30 20:24 About dma_sync_single_for_{cpu,device} karl.beldan
2012-07-30 20:34 ` karl.beldan
2012-07-31  6:45 ` Karl Beldan
2012-07-31  6:59   ` Clemens Ladisch [this message]
2012-07-31  7:27     ` Karl Beldan
2012-07-31  7:34       ` Clemens Ladisch
2012-07-31  8:30         ` Karl Beldan
2012-07-31  9:09   ` Russell King - ARM Linux
2012-07-31 19:31     ` Karl Beldan
2012-07-31 20:08       ` Russell King - ARM Linux
2012-08-01  6:50         ` Karl Beldan

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