Hi Rob,
On Thu, Apr 5, 2018 at 2:32 AM, Rob Herring robherring2@gmail.com wrote:
On Fri, Mar 16, 2018 at 8:51 AM, Geert Uytterhoeven geert@linux-m68k.org wrote:
If NO_DMA=y, get_dma_ops() returns a reference to the non-existing symbol bad_dma_ops, thus causing a link failure if it is ever used.
The intention of this is twofold:
- To catch users of the DMA API on systems that do no support the DMA mapping API,
- To avoid building drivers that cannot work on such systems anyway.
However, the disadvantage is that we have to keep on adding dependencies on HAS_DMA all over the place.
Thanks to the COMPILE_TEST symbol, lots of drivers now depend on one or more platform dependencies (that imply HAS_DMA) || COMPILE_TEST, thus already covering intention #2. Having to add an explicit dependency on HAS_DMA here is cumbersome, and hinders compile-testing.
The same can be said for CONFIG_IOMEM and CONFIG_OF. Any plans to remove those too? CONFIG_IOMEM is mostly just a !CONFIG_UM option.
Perhaps, if time permits...
Gr{oetje,eeting}s,
Geert