raw1394_start_iso_write ?

[Ken O. <ko...@ar...>]

Hi Andreas (et. al),

I'm looking for an explanation of the parameters for this routine:

int raw1394_start_iso_write(struct raw1394_handle *handle,
                            unsigned int channel,
                            unsigned int tag,
                            unsigned int sy,
                            unsigned int speed,
                            size_t length,
                            quadlet_t *data,
                            unsigned long rawtag);

Please correct me if I'm wrong in these assertions:

The "handle" parameter is returned from 
raw1394_get_handle().

The "channel" parameter is the isochronous channel to use
during transmission.  It ranges from 0 to 63?

The tag parameter should be either:

a. some register offset from CSR_REGISTER_BASE
   (perhaps CSR_REGISTER_BASE+CSR_FCP_COMMAND?)

b. some value which distinguishes the packet type from
   other packet types?

c. something else?

The "sy" parameter is a complete mystery to me.  Is it the
"Z" parameter that the 1394 Open Host Controller Interface
Specification references?

The "speed" parameter should be 1 for 100Mbits/sec, 2 for
200Mbits/sec and 3 for 400Mbits/sec (this I gleaned from the
1394 Open Host Controller Interface Specification referenced
from the links page).

The "length" parameter is the size of whatever data points to.

The "data" parameter is:

a. A pointer to a buffer of raw data to send

b. A pointer to some "DMA data-structure/program" that is described
   in the 1394 Open Host Controller Interface Specification.

c. Something altogether different.

d. An android serving on a starship in the 24th century. :)

The "rawtag" parameter is another mystery.  Is it the same value as
tag?

Any pointers you could offer would be greatly appreciated.

-- 
______________________________________________________________
Kenneth Ray Offer, II
Sr. Systems Analyst
Applied Research Laboratories/SDD
University of Texas at Austin
Office (512) 835-3859   FAX (512) 835-3259

Any opinions expressed above are mine and not necessarily
those of my employer.