= MutekH tutorial for SoCLib platform =

This guide explain how to run MutekH on a [wiki:Arch/Soclib SoCLib] hardware simulator.
This is allow easy experimentation with advanced multi-processor programming.

You are '''highly encouraged''' to first follow the [wiki:QuickStartUnix MutekH as Unix process quick start guide]
which introduces more basic concepts.

MutekH for SoCLib can be compiled for Mips, Arm, PowerPC processors.
Other processors are available with different platforms.

== The SoCLib platform ==

The MutekH kernel source code is fully configurable and can be tweaked to adapt hardware platform
and application needs. Configuration is handled by a dedicated tool which check dependencies and
other relationships between the large set of available configuration tokens.

The example below explains how to setup a SoCLib hardware simulator with 4 RISC processor (Mips, Arm or PowerPC).

[[BR]][[BR]][[Image(arch.png,nolink)]][[BR]][[BR]]

=== Getting SoCLib ===

We now need to have a working SoCLib install. SoCLib installation is explained here: https://www.soclib.fr/trac/dev/wiki/InstallationNotes

=== SoCLib platform description ===

The SoCLib source tree contains a platform dedicated to this tutorial:
{{{soclib/soclib/platform/topcells/caba-vgmn-mutekh_soclib_tutorial/}}}

=== Getting the cross-compilers ===

SoCLib installation nodes already provides a way to get cross-compiler, if you don't already have them, MutekH holds a tool
to build a complete cross-compilation toolchain:

The script is in [source:trunk/mutekh/tools/crossgen.mk@1183 tools/crossgen.mk]:
{{{
 $ tools/crossgen.mk
[prints some help]
 $ tools/crossgen.mk all TARGET=mipsel-unknown-elf
}}}

== The MutekH part ==

=== Getting the sources ===

{{{
svn co -r 1183 https://www-asim.lip6.fr/svn/mutekh/trunk/mutekh
}}}

=== Writing the example source code ===

Note: This example is available directly from [source:trunk/mutekh/examples/hello@1183 examples/hello] directory in source tree.

 * Writing the source code in `hello.c`
{{{
#include <pthread.h>

pthread_mutex_t m;
pthread_t a, b;

void *f(void *param)
{
  while (1)
    { 
      pthread_mutex_lock(&m);
      printf("(%i) %s", cpu_id(), param);
      pthread_mutex_unlock(&m);
      pthread_yield();
    }
}
int main()
{
  pthread_mutex_init(&m, NULL);
  pthread_create(&a, NULL, f, "Hello ");
  pthread_create(&b, NULL, f, "World\n");
}
}}}

 * Writing the `Makefile`
{{{
objs = hello.o
}}}


=== Writing the MutekH configuration ===

The MutekH configuration for the 4 Mips processors platform is in the [source:trunk/mutekh/examples/hello/config examples/hello/config] file.

This file only holds information about the application (here a simple pthread application) and relies upon files in the [source:trunk/mutekh/examples/common@1183 examples/common] directory for the platform definitions.

Have a look to the BuildSystem page for more information about configuration system and configuration file format.

The [http://www.mutek.fr/www/mutekh_api/ MutekH API reference manual] describes all available configuration tokens.

=== Platform description ===

The MutekH software uses hardware enumeration to get details about available hardware in the platform, so the `CONFIG_ARCH_DEVICE_TREE` token is defined in the [source:trunk/mutekh/examples/common/platforms-soclib.conf@1183 examples/common/platforms-soclib.conf] configuration file. It will let the kernel get the platform layout description from a FlattenedDeviceTree which will be built into the kernel.

Therefore, the build also compiles the correct FlattenedDeviceTree from the platform name.

The current FlattenedDeviceTree source file is
[source:trunk/mutekh/examples/common/pf_soclib_tutorial_ppc.dts examples/common/pf_soclib_tutorial_ppc.dts],
[source:trunk/mutekh/examples/common/pf_soclib_tutorial_arm.dts (for arm)],
[source:trunk/mutekh/examples/common/pf_soclib_tutorial_mips.dts (for mips)].

=== Compiling the application along with MutekH ===

The MutekH kernel and the application may be built out of the source tree.

Change to the SoCLib platform directory and apply the following steps to experiment
with out of tree compilation. You have to setup the following variables:

 `MUTEKH_DIR`::
   Path to MutekH source tree
 `APP`::
   Path to application source
 `CONFIG`::
   MutekH configuration file name
 `BUILD`::
   MutekH build option list (target architecture, cpu type, …)

See the `config.mk` file in the tutorial platform directory for more information.

{{{
$ cd soclib/soclib/platform/topcells/caba-vgmn-mutekh_soclib_tutorial
$ make MUTEKH_DIR=/path/to/mutekh
}}}

This will build the MutekH kernel along with the application.
You can still build MutekH separately as explained in the first part. The simulator can then be built using:

{{{
$ cd soclib/soclib/platform/topcells/caba-vgmn-mutekh_tutorial
$ make system.x
}}}

== Execution ==

You can optionally pass an alternative kernel to the simulator, but this defaults to the correct kernel name if you followed the tutorial until here.
{{{
$ ./system.x mutekh/kernel-soclib-ppc.out
}}}

You may want to refer to other articles and documents available from the main page to go further with MutekH.

The [soclib:wiki: SoCLib] home page provides a livecd image with more advanced examples ready to compile and run. These examples are using older MutekH revisions though.

Other more advanced topics and guides are available from the [wiki: Main page].