Re: [XenPPC] [xenppc-unstable] [XEN][POWERPC] SCOM access is fully known and working

[Segher Boessenkool <segher@xxxxxxxxxxxxxxxxxxx>]

> +    /* these give iface errors because the address is ambiguous after
> +     * the above bit dropping */
> +    BUG_ON(addr == 0x8000);
Anything with the high bit set isn't available via SCOMC/SCOMD,
only via the external interfaces.

> +        /* WARNING! older 970s (pre FX) shift the bits right 1  
> position */
They also don't have the exact same stuff at the exact same
registers -- SCOM is very CPU-specific, check every one you
want to use.  That is, if you do the fix for the shifted bits,
if not, don't bother ;-)

> +        if (c.bits.iface_error)
> +            udelay(10);
Why the udelay()?

> +/* SCOMC addresses are 16bit but we are given 24 bits in the
> + * books. The low oerder 8 bits are some kinda parity thin and should
> + * be ignored */
The low bit is the odd parity of the other 23 bits; everything
accessible via SCOMC/SCOMD has bits 16..22 zero.


All these comments are pretty minor, congratz on finally having
it working Jimi :-)


Segher


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