lkml.org 
[lkml]   [2017]   [Jun]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 3/7] asm-generic/io.h: make ioread64 and iowrite64 universally available
On Thu, 22 Jun 2017 14:24:58 -0600
Logan Gunthorpe <logang@deltatee.com> wrote:

> On 6/22/2017 2:14 PM, Alan Cox wrote:
> > If a platform doesn't support 64bit I/O operations from the CPU then you
> > either need to use some kind of platform/architecture specific interface
> > if present or accept you don't have one.
>
> Yes, I understand that.
>
> The thing is that every user that's currently using it right now is
> patching in their own version that splits it on non-64bit systems.
>
> > It's not safe to split it. Possibly for some use cases you could add an
> > ioread64_maysplit()
>
> I'm open to doing something like that.

I think that makes sense for the platforms with that problem. I'm not
sure there are many that can't do it for mmio at least. 486SX can't do it
and I guess some ARM32 but I think almost everyone else can including
most 32bit x86.

What's more of a problem is a lot of platforms can do 64bit MMIO via
ioread/write64 but not 64bit port I/O, and it's not clear how you
represent that via an ioread/write API that abstracts it away.

Alan

\
 
 \ /
  Last update: 2017-06-22 22:37    [W:1.709 / U:0.020 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site