At the beginning of February I posted [1] that I had a
SiI3124 (SATA-II, RAID,
PCI-X) card (works in PCI slot, too) for testing and that
worst-case I would
write the driver myself. Since there was no response, I
wrote the driver
myself.
Mostly, anyway. I've written it to be part of the ata driver
(long term this
does not seem like a good idea, what with PMs pushing the
number of devices
per SATA channel > 1; having one CAM bus would be doable,
I think, since 4
ports * hypothetical 15-port-multiplier is as far as this
chipset can go) and
so far it handles interrupts and ATA IDENTIFY returns the
correct
information. So I end up with (paraphrase, the machine I
have the hardware in
isn't connected today):
atapci1: SiI 3124
ata6: <channel 0 on atapci1>
..
ata9: <channel 3 on atapci1>
ad12: TOSHIBA ... on ata6-master
Anyway, I'm having real trouble figuring out how the
hw.begin_transaction,
hw.end_transaction and hw.status methods interact in struct
ata_lowlevel.
Commands are issued (like ATA INDENTIFY) and go through
begin_transaction. I
post the command to the device. On next interrupt for the
channel (meaning
the command is completed) .. something. This is where I
don't understand what
is happening or what is supposed to happen. status returns 0
or 1; in
ata-chipset.c these are typically documented as "have
seen any device
action", but I don't know entirely what this is
supposed to check. Given the
context I may be able to just return 1, but ata_pci_status()
returns 0 if the
channel is busy (by the taskfile registers).
And then there's the end_transaction stuff; this should,
presumably, set
request->result and request->error and
request->status. Here, I'm in the dark
as to what values mean what. I've tried just retrieving them
from the
taskfile (on the assumption that the 3124 updates the FIS
after command
completion) but all I get for my trouble are request
timeouts for SETMODE,
ENABLE_WCACHE, ... and the occasional READ_LBA. Booting this
way takes a long
time, but eventually the ATA system gives up on the disk and
boot continues
normally -- woe betide if I try dd if=/dev/ad12 though 
So my question is particularly: what are status and
end_transaction expected
to do? Is there documentation anywhere? dev/ata/* seems very
light on
how-it-works and design docs -- although the code is clean
and usually
explains what it is doing, so I've been able to get this
far.
[1]
http://lists.freebsd.org/pipermail/
freebsd-hardware/2007-February/004184.html
--
Adriaan de Groot
KDE Quality Team http://www.en
glishbreakfastnetwork.org/
SQO-OSS Researcher http://www.sqo-oss.eu/
_______________________________________________
freebsd-hardware freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-hard
ware
To unsubscribe, send any mail to
"freebsd-hardware-unsubscribefreebsd.org"
|
