lkml.org 
[lkml]   [2014]   [Jun]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v2 1/4] dma-mapping: Add devm_ interface for dma_map_single()
On 06/06/14 19:01, Greg KH wrote:
>> Please try to put yourself in my position: I have a driver that I care
>> > about, which works fine for a few years. It's based upon dma_map_single(),
>> > which seems to be the common way to get non-coherent memory, even for the
>> > driver's entire lifespan. I realize that dma_alloc_* was the intended way to
>> > do it, but fact is that dma_map_* has become the common choice.
>>
> Is your driver in the kernel tree? If not, you really are on your own :(
>
It's the Xillybus driver in the staging area. I don't know if this
counts for being in the kernel tree...

The suggested patchset would allow replacing my use of dma_map_single()
with a managed version of that function. This will clean the driver's
code considerably.

But I think that the discussion here is if it's valid to use
dma_map_single() for a device-permanent DMA mapping, or if
dma_alloc_noncoherent() is the only way. If the answer is no, there's
quite obviously no point in a devres version for that function.

Regards,
Eli
> greg k-h
>
>




\
 
 \ /
  Last update: 2014-06-06 18:41    [W:0.078 / U:1.252 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site