Re: [Xenomai-help] Omap3630, rtserial, xeno_16550A: crash on insmod

[Manfred <manfred@domain.hid>]

Ok, so this is my first attempt on trying to debug a kernel module,   so 
please bear with me:
First, I repeated what I did before: 

1.) setserial /dev/ttyS0 uart none 

2.)modprobe xeno_16550A mem=0x4806a000 irq=72 baud_base=3000000 

3.) dmesg->error message with: 

Unhandled fault: external abort on non-linefetch (0x1028) at 0xfa06a002 

Obtain Address-offset Ad1=0xfa06a002 

4.) get address-offset Ad0 from less /proc/modules: 

xeno_16550A 14280 1 - Loading 0xbf104000 

5.) obtain Ad2=Ad1+Ad0 (google says: 0xbf104000 + 0xfa06a002 = 
0x1B916E002)
6.) search for the last octet in the dissassembled kernel-module: 

objdump -d -S 
/lib/modules/2.6.38/kernel/drivers/xenomai/serial/xeno_16550A.ko
  > xeno16550A.diss 

grep -i B916E002 xeno16550A.diss 

7.) --> does not return anything? did I get something wrong?

Thanks for your help.

On 1/12/12 7:44 PM, Gilles Chanteperdrix wrote:
> On 01/12/2012 06:53 PM, Manfred wrote:
>> Dear Xenomai-Developers/Users,
>>
>> I am trying to get xenomai running on an omap3630 device (gumstix overo).
>> xenomai 2.6.0/kernel: linux-omap3-2.6.38 / i-pipe patch 2.6.38.8-arm-1.18.04
>>
>> I would like to use the UART devices in a RT-application,
>>    and I was following the following guidelines:
>> http://www.xenomai.org/index.php/16550A
>>
>> I had to do some changes to Kconfig in arch/arm/mach-omap2:Kconfig,
>> so that the omap_serial driver would not be compiled-in and so that
>>    I could actually disable the driver with setserial
>> (and correspondingly had to make some changes here and there because the
>>    devices are now called /dev/ttySx and not /dev/ttyOx, as in the
>> omap_serial driver...)
>>
>> dmesg then reports:
>> serial8250.0: ttyS0 at MMIO 0x4806a000 (irq = 72) is a ST16654
>> serial8250.1: ttyS1 at MMIO 0x4806c000 (irq = 73) is a ST16654
>> serial8250.2: ttyS2 at MMIO 0x49020000 (irq = 74) is a ST16654
>> serial8250.3: ttyS3 at MMIO 0x49042000 (irq = 80) is a ST16654
>>
>> Anyway, finally I was able to the following:
>>   >setserial /dev/ttyS0 uart none
>>   >modprobe xeno_16550A mem=0x4806a000 irq=72 baud_base=3000000
>>
>> (parameters same as here:
>> http://www.mail-archive.com/xenomai@xenomai.org
>> )
>>
>> And then I immediately get the following Error:
>>
>> --------------------
>> Unhandled fault: external abort on non-linefetch (0x1028) at 0xfa06a002
>
> The address is not aligned on a 4 bytes boundary, and clearly in the
> ioremap/vmalloc range, so, disassemble the module code and check what
> happens at bf0f0170 (you have to add the module load address as from
> /proc/modules to the addresses obtained when disassembling the .ko
> file), if you see an "ldrh" there, then something went wrong with the
> mapping of hardware registers. If you see an "ldr", then you get an
> unaligned access.
>
>> pc : [<bf0f0170>]    lr : [<bf0f011c>]    psr: 60000013
>
>