Re: [Qemu-devel] [PATCH 5/5] arm: SoC model for Calxeda Highbank

[Igor Mitsyanko <i.mitsyanko@gmail.com>]

On 06.01.2012 11:11 PM, Andreas Färber wrote:
> Am 06.01.2012 20:10, schrieb Igor Mitsyanko:
>> On 01/06/2012 10:45 PM, Peter Maydell wrote:
>>> On 6 January 2012 18:37, Igor Mitsyanko<i.mitsyanko@gmail.com>   wrote:
>>>> On 01/06/2012 12:02 AM, Mark Langsdorf wrote:
>>>>> +    if (!cpu_model) {
>>>>> +        cpu_model = "cortex-a9";
>>>>> +    }
>>>>
>>>>
>>>> Google said there is only cortexA9-based Highbank SoC version, maybe you
>>>> should just hardcode cpu model?
>>>
>>> This is just boilerplate code for any random ARM board at the moment:
>>> it defaults the CPU but lets the user override. We should either make
>>> a decision to do something else for all boards, or follow the usual
>>> convention here; I'm happy to do the latter.
>>>
>>
>> Are you saying that it's a mistake that we hardcoded cpu model and
>> memory size for Exynos boards in our patches?
>
> No machine should silently change the user's -cpu to something else.
> Either error out or warn the user, or let them face the consequences of
> their parameters themselves.

Machines do not instantiate cpus, they instantiate SoC models, which are 
solid (not modular) devices with explicitly specified (in datasheet or 
elsewhere) cpu core and peripheral devices, and if someone creates 
Highbank SoC instance with Cortex-M4 CPU core then it's no longer a 
Highbank SoC. What I mean, peripheral devices on SoC are not 
configurable, you cannot add additional UART or I2C interface, why allow 
cpu model change?

> Not sure how hardcoding the cpu_model would work with CPU features,
> would they be still included or stripped out before. Peter?
>

What do you mean? All features are currently set during 
cpu_reset_model_id() as far as I know, it doesn't matter whether 
cpu_model was specified on command line or hardcoded into initialization 
code.