RTEMS sound device driver

[Pattara Kiatisevi]

Hi,

I am going to write a device driver for a sound device to be run with RTEMS and
LEON chip. As I have very little experience with RTEMS, I have some questions:

Client program that will use this device driver:
================================================

-in Linux I do: 
	audio_fd = open("/dev/dsp",O_WRONLY , 0)
-in RTEMS: 
	Will the above open() work? or do I have to:
	rtems_io_open( xxx )? And how can I know what "xxx" should be?

-in Linux I do: 
	int format = AFMT_S16_LE;
	ioctl(audio_fd, SNDCTL_DSP_SETFMT, &format);
-in RTEMS?
	What should I do?

-in Linux I do:
	sizewritten = write(audio_fd, audio_buffer, inputsize);
-in RTEMS:
	I should use rtems_io_write() right? And how about the parameters?

Device driver:
==============

-The place that I have to put the device driver code is under
<rtems>/c/src/lib/libbsp/sparc/leon/ right? As I couldn't find any implementation of audio driver before, does it have any template so that I could know which functions should exist in order to support the above client calls?

I'm porting Ogg Vorbis Player (which runs on Linux/UNIX) to RTEMS. At first I
think that it could be sth. like "source-code compatible" but in the real 
it is not right?
 
Thank you for all answers,
Pattara