lkml.org 
[lkml]   [2018]   [Nov]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v3 1/1] drm: msm: Replace dma_map_sg with dma_sync_sg*
On Thu, Nov 29, 2018 at 09:24:17AM -0800, Tomasz Figa wrote:
> Whether the cache maintenance operation needs to actually do anything
> or not is a function of `dev`. We can have some devices that are
> coherent with CPU caches, and some that are not, on the same system.

Yes, but that part is not decided by these low-level helpers but their
callers in the DMA code (or maybe IOMMU code as well in the future).

> There is also the use case of using CMA with device-specific pools of
> memory reusable by the system when not used by the device and those
> would have to somehow get the pool to allocate from, but I wonder if
> struct device is the right way to pass such information. I'd see the
> pool given explicitly like cma_alloc(struct cma_pool *, size, flags)
> and perhaps a wrapper cma_alloc_default(size, flags) that is just a
> simple macro calling cma_alloc(&cma_pool_default, size, flags).

Yes, the cma APIs have quite a few warts that need addressing.
I have a few of those things on my todo list, but help is always
welcome.

\
 
 \ /
  Last update: 2018-11-29 19:35    [W:0.145 / U:6.988 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site