[U-Boot] [PATCH] mx31: Improve the handling of unidentified silicon version

[Fabio Estevam]

Hi Stefano,

On 6/15/2011 2:29 AM, Stefano Babic wrote:
...
> 
> Why is the new output better as we have now ? You drop the output of
> the srev register, and then we cannot get which strange silicon version
> is running without patching the code.

Let me try to explain the problem I see with the current silicon detection mechanism:

On my board (srev=0x28), which is a TO2.0 silicon I get:

CPU:   Freescale i.MX31 rev 2.0 at 531 MHz.Reset cause: WDOG

On Felix´s MX31ADS board (srev=0x20) (unknown chip version) he gets:

CPU:   Freescale i.MX31 rev 2.0 unknown at 531 MHz.Reset cause: WDOG

Reading rev 2.0 on Felix´s case is misleading IMHO as we tend to think that we have a TO2.0 silicon on his board even though we get a "unknown" string.

The reason of this is that we currently return the .v struct when the silicon version is detected and the srev version when it is not recognized.


>>  		if (srev == mx31_cpu_type[i].srev)
>>  			return mx31_cpu_type[i].v;
>>  
>> -	return srev | 0x8000;
>> +	return 0x8000;
> 
> IMHO in the case the revision is not recognized, it is better to print
> the value of the srev register, as it is done now. 

Yes, agreed, but we should print srev as an hex number instead of a string as done today

If you agree I can implement the following logic:

When the chip version is detected let´s just leave as it is today:

CPU:   Freescale i.MX31 rev 2.0 at 531 MHz.Reset cause: WDOG

When the chip version is not valid, then we print:

CPU:   Freescale i.MX31 (unknown rev, srev=0x20) at 531 MHz.Reset cause: WDOG

Please let me know what you think about this proposal.

Thanks,

Fabio Estevam