[U-Boot] [PATCH] p1022ds: fix switching of DIU/LBC signals

[Liu Dave-R63238]

>>      /* There is no __raw_writeq(), so do the write manually */
>>      *(volatile u64 *)addr = value;
>> -    if (sw)
>> +    if (sw) {
>> +            /*
>> +             * To ensure the post-write is completed to eLBC, software must
>> +             * perform a dummy read from one valid address from eLBC space
>> +             * before changing the eLBC_DIU from NOR mode to DIU mode.
>> +             */
>> +            __raw_readb(addr);
>>              set_mux_to_diu();
>> +    }
>
> Careful with the barriers.
>
> You've got a raw readback, which means it's not going to wait for
> completion with the twi/isync hack.
>
> Ordinarily that would be OK, since you only need ordering between the
> readb and the first access in set_mux_to_diu().  Unfortunately, that
> first access is an 8-bit access, which for some strange reason does
> sync differently than 16/32-bit accesses.  The latter do sync+write,
> but 8-bit does write+eieio.  So there's no barrier between the read
> and the write.

Any reason not to use in_8 here?

Timur,
Any reason not to use in_be8?
The first version code is finished by me some months ago. at that time I used the in_be8.

Thanks,
 Dave