[U-Boot] [PATCH] powerpc/mpc85xx:Disable Debug TLB entry for non-minimal SPL

[Scott Wood <scottwood@freescale.com>]

On 07/01/2013 03:56:23 AM, Prabhakar Kushwaha wrote:
> On 06/28/2013 09:49 PM, Scott Wood wrote:
>> On 06/28/2013 04:05:43 AM, Prabhakar Kushwaha wrote:
>>> On 06/27/2013 12:36 AM, Scott Wood wrote:
>>>> On 06/25/2013 11:09:04 PM, Prabhakar Kushwaha wrote:
>>>>> then it should be like this. slightly complex.
>>>>> #if defined(CONFIG_SYS_PPC_E500_DEBUG_TLB) &&  
>>>>> !(defined(CONFIG_NAND_SPL) || \
>>>>>     (defined(CONFIG_SPL_BUILD) &&  
>>>>> defined(CONFIG_SPL_INIT_MINIMAL)))
>>>>> 
>>>>> or
>>>>> #if defined(CONFIG_SYS_PPC_E500_DEBUG_TLB) &&  
>>>>> (CONFIG_SYS_RAMBOOT) || \
>>>>>     (defined(CONFIG_SPL_BUILD) &&  
>>>>> !defined(CONFIG_SPL_INIT_MINIMAL)))
>>>> 
>>>> The former:
>>>> 
>>>> http://lists.denx.de/pipermail/u-boot/2013-June/157201.html
>>>> 
>>> The defines mentioned at this link and earlier written by me will  
>>> not work as they are not taking care of SD boot and NOR boot  
>>> scenario.
>> 
>> How so?
>> 
>>> Below define will take care of all possible combination
>>>  - NOR , SD, SPI boot
>>>  - NAND_SPL
>>>  - SPL with SPL_INIT_MINIMAL
>>>  - SPL without SPL_INIT_MINIMAL
>>> 
>>> #if defined(CONFIG_SYS_PPC_E500_DEBUG_TLB) &&  
>>> !defined(CONFIG_NAND_SPL) && \
>>>     (!defined(CONFIG_SPL_BUILD) ||  
>>> !defined(CONFIG_SPL_INIT_MINIMAL))
>>> 
>>> Took lot of time to figure out :)
>> 
>> That's equivalent to what I suggested in the above link.  You just  
>> replaced !(x && y) with (!x || !y).
>> 
>> Or relative to your original suggestion above, you replaced !(x ||  
>> (y && z)) with !x && (!y || !z).
>> 
>> They're all logically equivalent[1].  The question is just which one  
>> is most readable/intuitiv
> 
> 
> We have below mentioned issues with defines :-
> 
> A)  Earlier suggested by me
> #if defined(CONFIG_SYS_PPC_E500_DEBUG_TLB) &&  
> !(defined(CONFIG_NAND_SPL) || \
>     (defined(CONFIG_SPL_BUILD) && defined(CONFIG_SPL_INIT_MINIMAL)))
> 
> This will cause compile failure in SPL build.
> in SPL build, CONFIG_NAND_SPL is not defined hence "1" making  
> disable_tlb() present. As SPL + SPL_INIT_MINIMAL does not have TLB  
> related functions means compilation error.

In that case CONFIG_SPL_BUILD and CONFIG_SPL_INIT_MINIMAL will be  
defined, which means (defined(CONFIG_NAND_SPL) ||  
(defined(CONFIG_SPL_BUILD) && defined(CONFIG_SPL_INIT_MINIMAL))) will  
be true, which means the negation will be false, which means the  
toplevel conjunction will be false, and disable_tlb() will not be  
called.

Again, unless I'm misreading something, this is 100% logically  
equivalent to your final suggestion.  I tried copy-and-pasting the  
above and had no problem building P2020RDB-PC_NAND.

> B)  Define suggested at this link has  
> "http://lists.denx.de/pipermail/u-boot/2013-June/157201.html "
> #if defined(CONFIG_SYS_PPC_E500_DEBUG_TLB) && \
>     !(defined(CONFIG_SPL_INIT_MINIMAL) && defined(CONFIG_SPL_BUILD))  
> && \
>     !defined(CONFIG_NAND_SPL)
> 
> here, during SD & NOR boot,  CONFIG_SPL_BUILD is not defined. hece  
> complete define = 0.  this make disable_tlb not compile which is  
> wrong.

If CONFIG_SPL_BUILD is not defined, then !(anything &&  
defined(CONFIG_SPL_BUILD)) will be true.  Since the other terms of the  
toplevel conjunction will also be true, disable_tlb will be compiled.

-Scott