Subject: Re: documentation for sun DBRI stuff
To: None <port-sparc@netbsd.org>
From: Ingolf Koch <ingolf@knuut.de>
List: port-sparc
Date: 12/29/1999 17:03:31
On Mon, Dec 27, 1999 at 10:48:16AM -0700, Tim Rightnour wrote:
> According to a few references I found.. the T7250C is nearly identical to the
> DBRI chip found in sparcs. According to the linux driver, the T7903 is also
> very similar.
The T7250D (for which there is documentation in
http://www.lucent.com/micro/isdn/docs/DS97404.pdf) does not
have a CHI, so I believe, only the ISDN part is similar.
On the other hand, the T7903 seems to have additional DRAM
attached (containing command lists etc) -- on the sparcs,
these lists are located in main memory (AFAIK).
For an audio driver I am thinking of something like this:
dbri? at sbus? slot ? offset ? # multiple DBRIs possible
audio? at dbri0 # hardwired to dbri0
audio? should use the CS4215 driver (to be written) in this
case. Is this a reasonable design?
The audio driver has to allocate CHI time slots from
the dbri. Is there a naming convention for functions
providing this kind of resource allocation?
The driver for the CS4215 codec probably is machine/arch independent,
while the attachment to the dbri chip (and the dbri chip itself)
is not -- at least, sbus is required. What do you think of the
following?
sys/dev/sbus/dbri.[ch]
- autoconfig of the DBRI chip
- providing resource allocation and access functions for
attached devices (e.g. audio codec, ISDN)
sys/dev/ic/cs4215{{reg,var}.h,.c}
- implementing control of the codec (e.g. switching between
mono / stereo)
- uses functions supplied by sys/arch/sparc/dev/dbri.[ch]
sys/dev/sbus/audio_dbri.[ch]
- implemetation of the audio(9) interface
Should some of the files better be placed in sys/arch/sparc/dev?
What changes to the various "*files" files are necessary to
include the new files in kernel builds (I am rather new to
NetBSD kernel programming)?
Any comments are very welcome
Ingolf
--
Ingolf Koch Beste Kneipe in Jena-Ost
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