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

[Thierry Bultel <thierry.bultel@wanadoo.fr>]

Le 09/04/2013 09:36, Gilles Chanteperdrix a écrit :
> On 04/09/2013 08:27 AM, Thierry Bultel wrote:
> 
>> Le 08/04/2013 22:55, Gilles Chanteperdrix a écrit :
>>> 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.
>>>
>>>
>>
>> It works on what platform ? It does not in qemu. The boot hangs the same 
>> way.
> 
> 
> It works on omap4, a platform with global timers... So, what you are
> saying is that it is in fact the twd calibration which hangs?
> 

Probably related, I first did not notice it,
the  twd_get_clock() call fails in my case (See below; smp_twd: clock
not found: -2):

Is it safe to call twd_calibrate_rate in this case ?



tbultel@laois:~/Qemu/qemu-1.4.0$ ./arm-softmmu/qemu-system-arm -M
vexpress-a9 -kernel
/shared/Buildroot/output.linaro.vexpress-a9/images/uImage  -m 1024M
-serial stdio -append "console=ttyAMA0"
Booting Linux on physical CPU 0
Initializing cgroup subsys cpuset
Linux version 3.5.7-ipipe (tbultel@laois) (gcc version 4.7.3 20121001
(prerelease) (crosstool-NG linaro-1.13.1-4.7-2012.10-20121022 - Linaro
GCC 2012.10) ) #6 SMP Wed Apr 10 15:00:16 CEST 2013
CPU: ARMv7 Processor [410fc090] revision 0 (ARMv7), cr=10c53c7d
CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
Machine: ARM-Versatile Express
Memory policy: ECC disabled, Data cache writealloc
sched_clock: 32 bits at 24MHz, resolution 41ns, wraps every 178956ms
PERCPU: Embedded 9 pages/cpu @84626000 s14848 r8192 d13824 u36864
Built 1 zonelists in Zone order, mobility grouping on.  Total pages: 260096
Kernel command line: console=ttyAMA0
PID hash table entries: 4096 (order: 2, 16384 bytes)
Dentry cache hash table entries: 131072 (order: 7, 524288 bytes)
Inode-cache hash table entries: 65536 (order: 6, 262144 bytes)
Memory: 1024MB = 1024MB total
Memory: 975912k/975912k available, 72664k reserved, 0K highmem
Virtual kernel memory layout:
    vector  : 0xffff0000 - 0xffff1000   (   4 kB)
    fixmap  : 0xfff00000 - 0xfffe0000   ( 896 kB)
    vmalloc : 0xc0800000 - 0xff000000   (1000 MB)
    lowmem  : 0x80000000 - 0xc0000000   (1024 MB)
    modules : 0x7f000000 - 0x80000000   (  16 MB)
      .text : 0x80008000 - 0x805a0570   (5730 kB)
      .init : 0x805a1000 - 0x83d7da00   (57203 kB)
      .data : 0x83d7e000 - 0x83db98f8   ( 239 kB)
       .bss : 0x83db991c - 0x83e1f9ac   ( 409 kB)
SLUB: Genslabs=11, HWalign=64, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
Hierarchical RCU implementation.
NR_IRQS:256
smp_twd: clock not found: -2
I-pipe, 1.000 MHz clocksource