Re: [Xenomai] Kernel 3.5.7 not booting in qemu for vexpress-a9 with xenomai-2.6.2.1

[Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>]

On 04/08/2013 09:13 PM, Thierry Bultel wrote:

> Le 08/04/2013 10:05, Gilles Chanteperdrix a écrit :
>> On 04/08/2013 09:26 AM, Gilles Chanteperdrix wrote:
>>
>>> On 04/07/2013 09:52 PM, Thierry Bultel wrote:
>>>
>>>> Le 07/04/2013 17:06, Gilles Chanteperdrix a écrit :
>>>>> On 04/07/2013 11:31 AM, Thierry Bultel wrote:
>>>>>
>>>>>> Hi,
>>>>>>
>>>>>> I am using a vanilla 3.5.7 kernel in qemu-1.4.0
>>>>>> The base defconfig is the vexpress.
>>>>>>
>>>>>> I want to use xenomai-2.6.2.1 with it.
>>>>>>
>>>>>> The non-patched kernel boots fine, the patched one doesnot, there is
>>>>>> nothing on the console,
>>>>>> the boot logo does not comeand Qemu then takes 100% CPU.
>>>>>>
>>>>>> Here is my command line
>>>>>> ./qemu-1.4.0/arm-softmmu/qemu-system-arm -M vexpress-a9 -kernel
>>>>>> ./Buildroot/output.linaro.vexpress-a9/build/linux-3.5.7/arch/arm/boot/uImage
>>>>>> -append "console=ttyAMA0" -m 1024M -serial stdio
>>>>>>
>>>>>> Any ideas ? May I have missed something ?
>>>>>
>>>>>
>>>>> Well, vexpress is not in the list of machines supported by Xenomai. So,
>>>>> someone needs to port the I-pipe kernel to it.
>>>>>
>>>>>
>>>>
>>>> Hi Gilles,
>>>>
>>>> We already talked about the vexpress, it was at the beginning of the
>>>> rtcan discussion.
>>>> It used to work (and pretty well), my configuration was:
>>>>
>>>> linux-3.2.21+ipipe-core-3.2.21-arm-1.patch
>>>>
>>>> and I have just successfully tested
>>>>
>>>> linux-3.2.21+ipipe-core-3.2.21-arm-4.patch
>>>> as well.
>>>>
>>>> There is likely not much missing for having it working on the 3.5.7
>>>> kernel. I am taking a look.
>>>
>>>
>>> Someone did the port of the I-pipe patch to vexpress (but did not
>>> contribute it), the difference between vexpress and other cortex A9
>>> based SOCs is that it does not support global timers, the one used by
>>> the I-pipe patch as clocksource. The difference between 3.2 and later
>>> patches is probably that later patches unconditionally use the global
>>> timer. The fix around this is to add code do detect the cortex a9
>>> revision and do not register the global timers when the revision is too old.
>>>
>>
>>
>> Found the mail: "I just got a reply from ARM support and obviously I
>> missed the thing that my release of Cortex-A9 does NOT have a global
>> timer (they added it from r1p0, mine is r0p1)."
>>
>> You know what version your processor is by reading the first few lines
>> printed by the kernel:
>> CPU: ARMv7 Processor [411fc092] revision 2 (ARMv7), cr=10c53c7d
>>
>> 41 is used by all cores from ARM
>> fc09 represents the cortex a9
>>
>> The remaining 1 and 2 mean that this cortex a9 is an r1p2
>>
> 
> 
> Many thanks,
> I confirm that this fix makes vexpress boot in qemu:


Merged thanks. I believe you should keep the calculation of 
twd_timer_rate, otherwise the twd timers will not be calibratd 
correctly. The following:

http://git.xenomai.org/?p=ipipe-gch.git;a=commitdiff;h=9a776ad3c41fa1aef1b60d0cce5de3ca9dece42d;hp=82b6948fed3581e65bcce64b91b16140686263a7

Works for me.


-- 
                                                                Gilles.