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From: Rusty Russell <rusty@rustcorp.com.au>
To: sjur.brandeland@stericsson.com, "Michael S . Tsirkin" <mst@redhat.com>
Cc: Sjur =?utf-8?Q?Br=C3=A6ndeland?= <sjurbren@gmail.com>,
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        Linus Walleij <linus.walleij@linaro.org>,
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        linux-kernel@vger.kernel.org
Subject: Re: [RFCv2 1/2] virtio_console: Add support for DMA memory allocation
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Date: Mon, 10 Sep 2012 17:23:52 +0930
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sjur.brandeland@stericsson.com writes:

> From: Sjur Brændeland <sjur.brandeland@stericsson.com>
>
> Add feature VIRTIO_CONSOLE_F_DMA_MEM. If the architecture has
> DMA support and this feature bit is set, the virtio data buffers
> will be allocated from DMA memory. If the device requests
> the feature VIRTIO_CONSOLE_F_DMA_MEM, but the architecture
> don't support DMA the driver's probe function will fail.
>
> This is needed for using virtio_console from the remoteproc
> framework.

Sorry for the back and forth, I've been pondering MST's points.

If we make a new dma-multiport device (eg. ID 11), how ugly is the code?

It would be a virtio console with DMA buffers and no console, just the
multiport stuff.  This would have no impact on the current spec for
virtio console.

Thanks,
Rusty.