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Message-ID: <HE1PR0401MB2425871215B13AD0EFDCA5C3E6DE0@HE1PR0401MB2425.eurprd04.prod.outlook.com>
Date: Fri, 9 Mar 2018 18:29:41 +0000
From: Nipun Gupta <nipun.gupta@....com>
To: Christoph Hellwig <hch@....de>
CC: Robin Murphy <robin.murphy@....com>,
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Subject: RE: [PATCH 5/6] dma-mapping: support fsl-mc bus
> -----Original Message-----
> From: Christoph Hellwig [mailto:hch@....de]
> Sent: Thursday, March 08, 2018 13:11
>
> On Tue, Mar 06, 2018 at 04:41:56AM +0000, Nipun Gupta wrote:
> > Sorry for asking a trivial question - looking into dma_configure() I see that
> > PCI is used in the start and the end of the API.
> > In the end part pci_put_host_bridge_device() is called.
> > So are two bus callbacks something like 'dma_config_start' &
> 'dma_config_end'
> > will be required where the former one will return "dma_dev"?
>
> I'd just use dma_configure as the callback.
This would be a decent stuff.
>
> Currently the of_dma_configure and acpi_dma_configure are only used
> for PCI anyway, as no one else sets a non-NULL dma dev.
My understanding is that even the platform bus uses the of_dma_configure
and probably acpi_dma_configure too. So platform bus may also need the
callback implemented. Please correct me if my understanding is wrong.
I will submit the patch with 'dma_configure' callback implemented for
the busses shortly.
> For fsl-mc I suspect only of_dma_configure is relevanet, so just call that directly.
> If at some point we get enough busses with either OF or ACPI we could
> create a helper called from ->dma_configure for that.
Totally agree with this.
Thanks,
Nipun
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