RTEMS sound device driver

[Pattara Kiatisevi]

OK, meanwhile I am trying this static method as you suggested while
waiting for the new dynamic one. (In the hope also to understand more
about RTEMS)

1.I created sound.h in my local application directory containing:

#define SOUND_DRIVER_TABLE_ENTRY \
  { sound_initialize, sound_open, sound_close, \
    sound_read, sound_write, sound_control }
and the declarations of these 6 functions (copied from in console.h).

2.I created sound.c containing:

rtems_device_driver sound_initialize(
  rtems_device_major_number  major,
  rtems_device_minor_number  minor,
  void                      *arg
)
{
  rtems_status_code status;

  /*
   *  Register Device Names
   */

  status = rtems_io_register_name( "/dev/dsp", major, 0 );
  if (status != RTEMS_SUCCESSFUL)
    rtems_fatal_error_occurred(status);

  /*
   *  Initialize Hardware
   */


  return RTEMS_SUCCESSFUL;
}

For the rest 5 functions, I just have "return RTEMS_SUCCESSFUL;" inside.

3.In my application header, I have such thing like this:

[cut]
#define CONFIGURE_HAS_OWN_DEVICE_DRIVER_TABLE

#define CONFIGURE_MAXIMUM_DRIVERS 10

#include <console.h>
#include "sound.h"

rtems_driver_address_table Device_drivers[] = {
        CONSOLE_DRIVER_TABLE_ENTRY,
        SOUND_DRIVER_TABLE_ENTRY,
        { NULL, NULL, NULL, NULL, NULL, NULL }
};

#include <confdefs.h>

[cut]

#define open_mode 1
#define DEVICE_NAME "/dev/dsp"

[cut]
  /* Open sound device */
  if ( (audio_fd = open(DEVICE_NAME, open_mode, 0) ) == -1 ) {
    /* open of a device failed */
    perror(DEVICE_NAME);
    exit(1);
  }

Then I compiled and ran the code and got this error:

/dev/dsp: Too many open files in system

Do you have any clues?

Thank you very much,
Pattara

On Thu, 7 Feb 2002, Aaron J. Grier wrote:

> On Fri, Feb 08, 2002 at 12:02:33AM +0100, Pattara Kiatisevi wrote:
>
> > But how exactly is this "registering" process? I took a look at the
> > existing driver code as suggested and draft the steps as follow.
>
> rtems_io_register_name binds a name in filesystem space to the device
> driver.
>
> > -I create a file contained device driver's code: sound-driver.c
> > 	-Which should contain initialize(), open(), close(), read(),
> > write(), and control(). Arguments of these functions = like in console.c?
>
> yes.
>
> > 	-In the initialize() I would have sth. like:
> >
> > 	rtems_io_register_name( "/dev/dsp", major, 0 );
> >
> > -In my application file, I do open(), ioctl(), write(), close() to
> > /dev/dsp as usual.
>
> you understand correctly.
>
> > -And then how can I tell RTEMS to call this sound device driver when there
> > is access to /dev/dsp?
>
> after registering the device with rtems_io_register_name, you can
> perform standard operations like open(), close(), lseek(), dup(), etc.
> on your file.  RTEMS handles the "mid level" between these calls and
> your device driver calls.
>
> > Something to do with #def CONFIGURE_HAS_OWN_DEVICE_DRIVER_TABLE and I
> > have to create my own Device_drivers? (Hmm, but how and where? :) )
>
> look at c/src/lib/include/console.h.  you define a table entry, and the
> extern declarations for your driver entry points, then somewhere in your
> confdefs.h:
>
> #define CONFIGURE_HAS_OWN_DEVICE_DRIVER_TABLE
>
> #include <console.h>
>
> rtems_driver_address_table Device_drivers[] = {
>         CONSOLE_DRIVER_TABLE_ENTRY,
>         { NULL, NULL, NULL, NULL, NULL, NULL }
> };
>
> getting everything glued in to autoconf/automake so that they will be
> compiled and linked into your BSP is a whole other story.  :)  let us
> know if you need help with that.
>
> --
>   Aaron J. Grier  |   Frye Electronics, Tigard, OR   |  aaron at frye.com
>      "In a few thousand years people will be scratching their heads
>        wondering how on earth the first computer was invented and
>           bootstrapped without a prior computer to do it with."
>                     --  Chris Malcolm, on comp.arch
>
>