Re: [PATCH] dma-mapping: move dma configuration to bus infrastructure

From: Christoph Hellwig
Date: Wed Mar 14 2018 - 05:02:28 EST


>> + .dev_groups = amba_dev_groups,
>> + .match = amba_match,
>> + .uevent = amba_uevent,
>> + .pm = &amba_pm,
>> + .dma_configure = amba_dma_configure,
>> + .dma_deconfigure = amba_dma_deconfigure,
>> + .force_dma = true,
>
> This patch should also be removing force_dma because it no longer makes
> sense. If DMA configuration is now done by a bus-level callback, then a bus
> which wants its children to get DMA configuration needs to implement that
> callback; there's nowhere to force a "default" global behaviour any more.

Btw, we don't really know how many busses currently rely on OF or ACPI
configuration. So maybe we need to keep those as a default?