lkml.org 
[lkml]   [2019]   [Nov]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH v4 04/47] soc: fsl: qe: introduce qe_io{read,write}* wrappers
From
Date
On 11/12/19 1:14 AM, Rasmus Villemoes wrote:
> but that's because readl and writel by definition work on little-endian
> registers. I.e., on a BE platform, the readl and writel implementation
> must themselves contain a swab, so the above would end up doing two
> swabs on a BE platform.

Do you know whether the compiler optimizes-out the double swab?

> (On PPC, there's a separate definition of mmio_read32be, namely
> writel_be, which in turn does a out_be32, so on PPC that doesn't
> actually end up doing two swabs).
>
> So ioread32be etc. have well-defined semantics: access a big-endian
> register and return the result in native endianness.

It seems weird that there aren't any cross-arch lightweight
endian-specific I/O accessors.

\
 
 \ /
  Last update: 2019-11-14 06:09    [W:0.158 / U:1.624 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site