Embedded PC IDE Flash Questions

[Chris Johns]

Joel Sherrill wrote:
> Chris Johns wrote:
>>
>> Is the device on the IDE bus set as the primary or second device ?
>>
>> I have found with testing that I have a primary and secondary disk 
>> configured with qemu but only the primary disk is being detected yet I 
>> can read both identities. I am looking into this.
>>
>>   
> I have no idea.  I posted the link to the manual for the
> board and it has ROM-DOS on it so I can check things.
> 

Yes you did and I have had a look and jumper J8 looks like it controls 
the master/slave setting for the CFlash. The CFlash is on IDE1. The 
manual states a jumper on 1-2 of J8 should make it a master and I 
suspect this is the default. If it was a slave I would have suspected 
the ATA issue I have found. So I am not sure what is happening here. In 
the manual the Main Menu Screen for the BIOS shows the CFlash as the 
Secondary Master.

On to the ATA issue I have found. I hacked out the ATA DIAG command 
which is run during initialisation to get qemu to run and if effected 
the slave device detection on a bus. Looking at the DIAG command a 
little more I do not like it. That could be my lack of understanding, 
but it means you need a master installed to detect a slave device. Maybe 
this is an electrical constraint but it seems silly if you do not. I 
took a look at the ATA module support in the latest grub sources and it 
does a simple port check, a reset then an identify. This makes sense to 
me. I have added a reset to the pc386 IDE driver.

I also found adding an identify command before the diag command caused 
the diag command to work on qemu so I tend to think it is not a common 
operation for boot loaders or qemu would have fixed it before now.

The IDE1 (second) interface still does not work on qemu. I have 
something connected which I think is a CDROM or an ATAPI device. This 
device does not complete the identify command so I am wondering if ATAPI 
does something else. Maybe we should have code to detect an ATAPI device 
and ignore it.

Finally I made the i386 BSP option number the IDE buses 1,2 etc. Should 
this be 0,1 etc ?

Regards
Chris