Difference between revisions of "Xenomai"

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(Selecting Xenomai package)
m (Xenomai kernel space support)
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  $ make
 
  $ make
 
'''kernel-2.6.38'''
 
'''kernel-2.6.38'''
*If the compilation stops, which is probabely the case for the first time, apply the following patches in : buildroot/output/build/linux-2.6.38.8  
+
* If the compilation stops, which is probably the case for the first time, apply the following patches in : buildroot/output/build/linux-2.6.38.8  
 
http://sourceforge.net/mailarchive/forum.php?thread_name=CAP%2B5e19GT6g%3Dx1zdTan7maz28qsJNRoNYpDz7w-BNWAgR5WO4w%40mail.gmail.com&forum_name=armadeus-forum
 
http://sourceforge.net/mailarchive/forum.php?thread_name=CAP%2B5e19GT6g%3Dx1zdTan7maz28qsJNRoNYpDz7w-BNWAgR5WO4w%40mail.gmail.com&forum_name=armadeus-forum
 
** adeos-00-avoid_kernel_panic.patch :
 
** adeos-00-avoid_kernel_panic.patch :

Revision as of 16:07, 17 February 2014

What is Xenomai ?

Xenomai is a real time co-kernel which cooperates with Linux via Adeos. With its help, hard real time applications can be developed and run on the Armadeus boards.

Thanks to Adeos, Xenomai will receive the interrupts first and decide to handle them or not. If not, they will then be transfered to the regular Linux kernel. Also, Xenomai provides a framework to develop applications which can be easily moved between the Real Time Xenomai environment and the regular Linux system.

Moreover, Xenomai provides a set of APIs (called "skins") that emulate traditional RTOSes such as VxWorks and pSOS and implement other APIs such as POSIX. Thus, porting third party real time applications to Xenomai is a fairly simple process.

Explanation of the process used to install Xenomai

Note Note: Xenomai has only be really tested on APF9328 and APF27 with 2.6.29 kernel. APF28 with 3.4 kernel and APF6 with 3.10.18 kernel are WiP.


The main steps are:

  • selection of Xenomai package on the Buildroot menuconfig,
  • selection of Xenomai features in Kernel menuconfig,
  • compilation of the new version,
  • validation of the Xenomai behaviour.
Note Note: These steps must be done with a fresh view or, at least, after having deleted buildroot/output/build/linux-x.y.z directory.


Selecting Xenomai package

  • First of all, you need to select Xenomai package and Adeos patch in Buildroot menuconfig:
 $ make menuconfig
...
Kernel --->
    Linux Kernel Extensions  --->
        [*] Adeos/Xenomai Real-time patch
        (http://download.gna.org/adeos/patches/v2.6/arm/older/adeos-ipipe-2.6.29-arm-1.13-05.patch) Path/url for Adeos patch file

Target packages  --->
    Real-Time --->
        [*] Xenomai Userspace
...
Note Note: It's possible to enable (or not) some skins in a first menu.
  • Exit and save your configuration
  • If you plan to use xeno-test (Xenomai performance tool) then CONFIG_ASH_GETOPTS should be activated in Busybox:
 $ make busybox-menuconfig
Shells  --->
        Choose your default shell (ash)  --->
    --- ash
    ---   Ash Shell Options
          ...
          [*]   Builtin getopt to parse positional parameters 
  • Exit and save your configuration
  • rebuild Busybox & Buildroot:
$ make busybox-clean && make

Kernel greater than 2.6.29

For kernels greater than 2.6.29, it's needed to suppress all patches in buildroot/packages/xenomai/ and then modify URL and Adeos patch name:

2.6.38

Kernel --->
    Linux Kernel Extensions  --->
        [*] Adeos/Xenomai Real-time patch
        (http://download.gna.org/adeos/patches/v2.6/$(BR2_ARCH)) Adeos patch URL
        (adeos-ipipe-2.6.38.8-arm-1.18-09.patch) Path for Adeos patch file
  • If you plan to use a 2.6.38 kernel you have to delete the following patches :
$ cd buildroot/package/xenomai
$ rm adeos-00-compatibility_with_armadeus.patch
$ rm adeos-01-adeos-prevent_system_freeze_on_mxc_with_gpio_generated_interrupts.patch
$ cd patches/linux/2.6.38.8
$ rm 401-armadeus-fix_clock_tree.patch
$ rm 419-armadeus-mx5fb-add_ipu_clock_polarity_support.patch

Xenomai kernel space support

  • At first time, to have Linux kernel patched with Xenomai and Adeos patches, you must type:
 $ make
  • If the script prepare-kernel.sh is missing, you can resolve this issue by:
$ make xenomai

Then resume the compilation:

$ make

kernel-2.6.38

  • If the compilation stops, which is probably the case for the first time, apply the following patches in : buildroot/output/build/linux-2.6.38.8

http://sourceforge.net/mailarchive/forum.php?thread_name=CAP%2B5e19GT6g%3Dx1zdTan7maz28qsJNRoNYpDz7w-BNWAgR5WO4w%40mail.gmail.com&forum_name=armadeus-forum

    • adeos-00-avoid_kernel_panic.patch :
--- a/arch/arm/plat-mxc/time.c	2012-09-01 16:06:04.000000000 +0200
+++ b/arch/arm/plat-mxc/time.c	2012-09-01 16:01:17.000000000 +0200
@@ -405,7 +405,8 @@

	if (timer_is_v1()) {
		tsc_info.u.counter_paddr = phys + MX1_2_TCN;
-		tsc_info.counter_vaddr =(unsigned long)(phys + MX1_2_TCN);
+		//tsc_info.counter_vaddr =(unsigned long)(phys + MX1_2_TCN);
+		tsc_info.counter_vaddr =(unsigned long)(timer_base + MX1_2_TCN);
	} else {
		tsc_info.u.counter_paddr = phys + V2_TCN;
		tsc_info.counter_vaddr = (unsigned long)(timer_base + V2_TCN);
    • xenomai-00-move-irq_to_desc-export.patch :
diff -ru '--exclude-from=linux-2.6.38.8/Documentation/dontdiff' linux-2.6.38.8/kernel/irq/irqdesc.c linux-2.6.38.8.new/kernel/irq/irqdesc.c
--- a/kernel/irq/irqdesc.c	2012-08-25 14:44:30.000000000 +0200
+++ b/kernel/irq/irqdesc.c	2012-08-25 12:17:44.000000000 +0200
@@ -268,13 +268,13 @@
	}
	return arch_early_irq_init();
}
-EXPORT_SYMBOL_GPL(irq_to_desc);

#ifndef CONFIG_IPIPE
struct irq_desc *irq_to_desc(unsigned int irq)
{
	return (irq < NR_IRQS) ? irq_desc + irq : NULL;
}
+EXPORT_SYMBOL_GPL(irq_to_desc);
#endif /* CONFIG_IPIPE */

struct irq_desc *irq_to_desc_alloc_node(unsigned int irq, int node)


  • Then you can configure the Xenomai kernel options from Linux menuconfig:
 $ make linux-menuconfig

You should see the new entry :

 Real-time sub-system  --->

Enter in it and check the following to compile Xenomai as a part of the Linux kernel :

 [*] Xenomai
   <*> Nucleus 
   [*]   Pervasive real-time support in user-space
   [ ]     Interrupt shield support
   [*]     Priority coupling support
   [*]   Optimize as pipeline head
   (32)  Number of pipe devices
   (512) Number of registry slots
   (128) Size of the system heap (Kb)
   (32)  Size of the private stack pool (Kb)
   [*]   Statistics collection
   [ ]   Debug support
   [ ]   Shared interrupts
      Timing  --->
      Scalability  --->
      Machine  --->
      Interfaces  --->
      Drivers  --->

Additionaly, to enable / disable the different available skins, go into Interfaces ---> :

 <*> Native API  --->
 <*> POSIX API  --->
 < > pSOS+ emulator  --->
 < > uITRON API  --->
 < > VRTX emulator  --->
 < > VxWorks emulator  --->
 < > RTAI emulator  --->
 <*> Real-Time Driver Model  --->

Finally, compile everything:

 $ make linux && make

Deploy

You can now transfer the rootfs and the kernel on the APF.

Validate the installation

  • Boot the APF and logon as root.
  • You can double check Xenomai is installed correctly:
 $ dmesg | grep Xenomai
  I-pipe: Domain Xenomai registered.
  Xenomai: hal/arm started.
  Xenomai: real-time nucleus v2.4.3 (Back to Shalla-Bal) loaded.
  Xenomai: starting native API services.
  Xenomai: starting POSIX services.
  Xenomai: starting RTDM services.
  • Now we can run the performance test provided by Xenomai:
 $ xeno-test

Deinstalling or disabling Xenomai

There are two parts needed for disabling Xenomai features

Kernel

For disabling kernel part, two solutions are available

  • The first solution is to unselect kernel's features :
 $ make linux-menuconfig

And disable following options:

Real-time sub-system --->
    [ ] Xenomai

and

Kernel Features ---> 
    [ ] Interrupt pipeline
  • The second solution is to destroy the kernel tree :
 $ make linux-dirclean

Userspace / package

For disabling userspace/package part :

 $ make menuconfig

and disable Xenomai

Package Selection for the target ---> 
    [ ] Xenomai

then use the dirclean command:

 $ make xenomai-dirclean

Going further

Links