Re: [PATCHv3 1/3] net: fec: do not use readl()/writel() for ColdFire

[Geert Uytterhoeven]

Hi Andrew,

On Wed, 23 Sept 2026 at 16:16, Andrew Lunn <andrew@xxxxxxx> wrote:
> > The driver will always need to support big and little endian hardware, so I
> > am not sure how to avoid some abstraction like this.
>
> I was wondering if there is a linux standard set of macros which is
> supposed to handle this big/little difference, the macro knows the
> architecture and does the correct thing?

Unfortunately not.

Quoting Arnd:
   "fec is an exception to this because it happened to rely on the
    unusual macros: all the Arm SoCs using this hardware have little-endian
    registers (regardless of whether the CPU runs as BE or LE), while
    all the coldfire chips use big-endian registers (and don't support
    LE kernels). The powerpc variant of fec also uses big-endian registers
    but has a separate copy of the driver that hardcodes this. Other
    Freescale drivers already have a runtime endianess detection that
    is needed because they built both BE and LE variants of the hardware
    on Arm SoCs that could run the same kernel."

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds