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IDE programming documents request ...
Posted: Fri Mar 28, 2003 8:01 am
by Pype.Clicker
i need more info about IDE programming, especially the content of the ATA_IDENTIFY returned pseudo-sector.
I've been through
http://www.nondot.org/sabre/os/files/Disk/IDE-tech.html, but it doesn't seem to explain everything.
For instance, where is explained that byte order from "model" string must be reversed ? and how can one make sure the HDD will support LBA ?
If some of you has extended knowledge to share ...
Re:IDE programming documents request ...
Posted: Fri Mar 28, 2003 3:21 pm
by distantvoices
merde, que j'ai oublie l'adresse excacte d'une website sur ATA ...
alors ...
A quick google search didn't throw it out anyway, so I'll search tomorrow. but I know there is a kind of ATA ressource center lingering around in internet. They offer drivers and source code and ressources ... Crap that I didn't bookmark it ... shame on me and glowing coals amongst my hair ...
Re:IDE programming documents request ...
Posted: Fri Mar 28, 2003 3:30 pm
by FlashBurn
Maybe you have a look at
http://www.t13.org.
Re:IDE programming documents request ...
Posted: Sat Mar 29, 2003 4:14 pm
by Pype.Clicker
hmmm ... seems to be a promizing link.
I'd like to apologize for my laziness ... my modem seems to have nervous breakdown these last days and googling is especially boring under these conditions ...
thanks alot.
Re:IDE programming documents request ...
Posted: Sun Mar 30, 2003 2:55 pm
by Pype.Clicker
eeek!?
I've got a strange behaviour while trying to detect IDE controllers. The code i use looks like
Code: Select all
byte r=inb(ATA_CYLINDER_LOW);
outb(ATA_CYLINDER_LOW,~r);
if (r==inb(ATA_CYLINDER_LOW) error("controller not found");
It has been borrowed to Tim's ata.c driver and expects that if a controller is present, then we should be able to read back a value we stored in registers like CYLINDER_LOW (that is supposed to be a place where we store info for a read/write request on the disk before the command is issued) but that the port will be read as a constant if there is no controller.
That code worked fine on bochs-1.4.x, but it fails on bochs 2.0.2 (it reads '0' both before and after the 'outb' command ?)
Do anybody experienced such a weird behaviour ?
Is the controller test really useful or is it enough to send an ATA_IDENTIFY command and see if a result is returned ?
Re:IDE programming documents request ...
Posted: Sun Mar 30, 2003 3:11 pm
by Therx
Maybe you just typed it wrong but in the last line the if statement is missing the closing bracket.
Re:IDE programming documents request ...
Posted: Sun Mar 30, 2003 3:23 pm
by Tim
That method of detection in my code is broken, at least on Bochs. I rely on sending IDENTIFY and waiting for a timeout, although that's obviously very slow. I haven't got round to finding a better solution yet, so maybe it's time one of us did.
Re:IDE programming documents request ...
Posted: Mon Mar 31, 2003 3:18 am
by Pype.Clicker
hmm ... some code extract from BOCHS 2.0.2
Code: Select all
case 0x04: // cylinder low 0x1f4
value8 = (!BX_SELECTED_IS_PRESENT(channel)) ? 0 : (BX_SELECTED_CONTROLLER(
channel).cylinder_no & 0x00ff);
goto return_value8;
Which seems to show that i should have selected the proper drive before starting to talk with the controller ...
BUT if i do select master drive and that it is not present (for instance, what if the IDE bus only has a slave CDROM, but no master ?) how will real hardware react ??
Are the CYLINDER_LOW, etc. registers buffered at the chipset, or do they directly alter the state of the disk's electronic ?
Maybe a valid test would be :
Code: Select all
atactrl::reset();
atactrl::select_drive(0);
if (atactrl::test()) goto found;
atactrl::select_drive(1);
if (atactrl::test()) goto found;
error("controller not found");
return false;
found:
// start identifying drives
where "atactrl::test()" performs the CYLINDER_LOW test and "atactrl::select_drive()" issues a outb to set/reset the drive select bit...
Re:IDE programming documents request ...
Posted: Wed Apr 02, 2003 4:00 pm
by srg