Messages in this thread | | | Date | Wed, 7 Mar 2012 17:20:00 +0100 | Subject | Re: [PATCH/RFC] dmaengine: add a slave parameter to __dma_request_channel() | From | Linus Walleij <> |
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On Wed, Mar 7, 2012 at 11:31 AM, Russell King - ARM Linux <linux@arm.linux.org.uk> wrote:
> For example, the SA11x0 IrDA driver uses two virtual channels, one for > receive and one for transmit. The SA11x0 has a total of five DMA > channels. To waste two of them on IrDA when it's half-duplex is just > silly. Doing the whole 'request+free' thing is also silly because > switching between tx and rx mode is timing-critical.
Oh. that's luxury! The ARM PB11MPcore has two physical DMA channels.
If I lock one up for say continous UART RX I have only one left, and that need to do everything else. So multiplexing the physical engines it is a must.
Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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