Well, better late than newer, but things has been hectic
around here, sorry for the long delay.
DMA support has been added to the ATA disk driver.
This only works on Intel PIIX3/4, Acer Aladdin and Promise controllers.
The promise support works without the BIOS on the board,
and timing modes are set to support up to UDMA speed. This
solves the problems with having more than one promise controller
in the same system.
There is support for "generic" DMA, that might work on other
controllers, but now you have been warned :)
More chipset specific code will come soon, I have to find testers
with the approbiate HW, more on that when I have it ready.
The system now uses its own major numbers, please run MAKEDEV
with the devices you need (ad?, acd?, afd?, ast?).
For now the disk driver will also attach to the old wd major
so one can at least boot without this step, but be warned, this
will eventually go away. The bootblocks will have to be changed
before one can boot directly from an "ad" device though.
Fixed problems:
All known hang problems should be solved
The probe code has been sligthly changed, this should solve
the reports I have lying around (I hope).
Hangs when accessing ata & atapi device on the same channel simultaniously.
A real braino in ata_start caused this, fixed.
As usual USE AT YOUR OWN RISK!!, this is still pre alpha level code.
Especially the DMA support can hose your disk real bad if anything
goes wrong, agaiin you have been warned :)
But please tell me how it works for you!
Enjoy!
-Søren
reports on those most welcome!
Fixed problems:
Hang on probe on "fantom" devices.
The probe now use a timeout to avoid hangs if no interrupt
is recevied.
There has also been more general code clenaups, and some reorgs.
interrupts are enabled, this kills the last "unwanted interrupts"
(and there is no ugly hacks like in the old driver to avoid them).
COmmand interrupt devices are now supported, this applies mostly
to older CDROM's and apparently also the ZIP.
Fixed problems:
Number of total sectors wrong on some older drives.
Fixed by not using the LBA size unless we know its valid.
There has also been more general code clenaups, some reorgs also.
Added "options ATA_STATIC_ID" that wires ATA disks like the old wd driver.
Fixed problems:
Dont use more sectors/intr than the drive supports.
Fix announce of > 8.4G disks.
Dont call ad_interrupt/ad_transfer when no disks config'd.
Use the right page# for CDR write mode params.
Fix breakage when no PCI support in kernel.
Implement DEVFS stuff.
General code clenaup.
The much roumored replacement for our current IDE/ATA/ATAPI is
materialising in the CVS repositories around the globe.
So what does this bring us:
A new reengineered ATA/ATAPI subsystem, that tries to overcome
most of the deficiencies with the current drivers.
It supports PCI as well as ISA devices without all the hackery
in ide_pci.c to make PCI devices look like ISA counterparts.
It doesn't have the excessive wait problem on probe, in fact you
shouldn't notice any delay when your devices are getting probed.
Probing and attaching of devices are postponed until interrupts
are enabled (well almost, not finished yet for disks), making
things alot cleaner.
Improved performance, although DMA support is still WIP and not
in this pre alpha release, worldstone is faster with the new
driver compared to the old even with DMA.
So what does it take away:
There is NO support for old MFM/RLL/ESDI disks.
There is NO support for bad144, if your disk is bad, ditch it, it has
already outgrown its internal spare sectors, and is dying.
For you to try this out, you will have to modify your kernel config
file to use the "ata" controller instead of all wdc? entries.
example:
# for a PCI only system (most modern machines)
controller ata0
device atadisk0 # ATA disks
device atapicd0 # ATAPI CDROM's
device atapist0 # ATAPI tapes
#You should add the following on ISA systems:
controller ata1 at isa? port "IO_WD1" bio irq 14
controller ata2 at isa? port "IO_WD2" bio irq 15
You can leave it all in there, the system knows how to manage.
For now this driver reuses the device entries from the old system
(that will probably change later), but remember that disks are
now numbered in the sequence they are found (like the SCSI system)
not as absolute positions as the old system.
Although I have tested this on all the systems I can get my hands on,
there might very well be gremlins in there, so use AT YOU OWN RISK!!
This is still WIP, so there are lots of rough edges and unfinished
things in there, and what I have in my lab might look very different
from whats in CVS at any given time. So please have all eventual
changes go through me, or chances are they just dissapears...
I would very much like to hear from you, both good and bad news
are very welcome.
Enjoy!!
-Søren
