[EARLY RFC][PATCH] dma-buf: Add dma-buf heaps framework

[Linus Walleij]

On Tue, Feb 26, 2019 at 3:12 PM Benjamin Gaignard
<benjamin.gaignard at linaro.org> wrote:

> Overall  I like the idea but I think "dma_heap" will be confusing like
> dma_buf is because it isn't
> related to DMA engine.

It wouldn't be the only place, in Device Tree we use "dma-ranges" in the
PCI bus host bindings to define how the PCI devices see the memory
on the host system, and it is called like that since the PCI devices indeed
perform direct memory access. And this is even system agnostic
and cannot be changed.

In the kernel we use dma_alloc_coherent() for allocating framebuffers
though what we want is physically contiguous.

I think it's a lost cause, we just have to remind everyone once a week
that DMA means "some device or component accessing the memory
directly without involvement of the CPU. Such as a display scan-out,
not to be confused with DMA engines".

FWIW it might be easier to rename DMA engines to "memmove and
stream" or "blitters". :/

Yours,
Linus Walleij