Re: [PATCH] [v2] watchdog: introduce the ARM64 SBSA watchdog driver

Timur Tabi
2015-05-14T23:49:17Z

Guenter Roeck wrote:
>
> We still don't know if the registers are in host byte order or in little
> endian
> order. If registers are in host byte order, there is no need for a
> conversion.

Well, if I compile and boot a big-endian ARM64 kernel, then I don't
expect the hardware devices to magically switch all their registers into
big endian. The devices will remain little-endian.

I presume that this is true on all ARM and ARM64 systems. Switching the
CPU into big-endian mode (when it normally would run in little-endian)
does not also switch the hardware registers.

Therefore, if we want to support big-endian kernels on ARM64, then every
readl/writel in every driver must use cpu_to_le32/etc.

I think this conversation has gone off-track. I don't see how the SBSA
watchdog device is any different from any other device on an ARM64 platform.

I think it's safe to say that the endian order is not specified
anywhere, but on my hardware, everything is little-endian.

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