Re: [PATCH] MdePkg: add big-endian MMIO BaseBeIoLib

[Laszlo Ersek <lersek@redhat.com>]

On 04/17/18 10:15, Udit Kumar wrote:
> Hi Laszlo, 
> 
> Considering all possible option is best to have in code 😊 
> But IMO, We are running UEFI on LE CPU only, Not sure someone is running on BE. AFAIK even specs says LE. 
> 
>> (c) assuming we introduce a CPU with BE byte order, the same driver
>>     source will work (for both LE and BE devices), only the lib
>>     instances will have to be switched around. (This might even happen
>>     dynamically, via function pointers.)
> 
> I assume , when we say CPU in BE , this means we are talking here new CPU architecture
> and new SOC.  So I expect some changes in hardware IP as well.
> If not then, I see still this working with patch of Leif 
> 
> Like 
> CPU (LE,) Driver (LE) Uses Mmio
> CPU (LE,) Driver (BE) Uses BeMmio (Mmio with swap)
> 
> CPU (BE,) Driver (LE) Uses Mmio (Does read and Swap) <-- This will be new Mmio Lib for particular architecture 
> CPU (BE,) Driver (BE) Uses BeMmio (Mmio with swap)  <-- Swap of swap will make same value 
> 
> With this, I see driver code is same irrespective of CPU arch 
> 
> thoughts ? 

Apparently I've needlessly complicated things already. Feel free to
proceed as you see fit.

Laszlo