On Thu, 23 Dec 2004, Daniel Drake wrote:
> The hp8200e init function does this:
>
> 730 // Write 0x80 to ISA port 0x3F
> 731
> 732 if (usbat_write(us, USBAT_ISA, 0x3F, 0x80) !=
> 733 USB_STOR_XFER_GOOD)
> 734 return USB_STOR_TRANSPORT_ERROR;
> 735
> 736 US_DEBUGP("INIT 6\n");
> 737
> 738 // Read ISA port 0x27
> 739
> 740 if (usbat_read(us, USBAT_ISA, 0x27, status) !=
> 741 USB_STOR_XFER_GOOD)
> 742 return USB_STOR_TRANSPORT_ERROR;
>
> The usbat02-flash init doesn't. I was hoping that reading/writing to those
> registers on the flash device would fail (that would provide an easy
> distinction) but unfortunately thats not the case.
>
> What do these reads/writes do? I did some searching but couldn't find any ISA
> specs that didn't require me to pay for them.
I have no idea.
> On the flash-devices, ISA port 0x27 originally reads 0xEC. After performing
> the same write as shown above, ISA 0x27 then reads 0x80.
Now you're confusing me. I thought these chips provided a USB-ATA
interface. Here you're talking about ISA registers. But ISA is a
motherboard architecture; it includes a lot more than just ATA. Does this
mean that the chips essentially provide an entire motherboard at the far
end of the USB link? Could you plug in an AT-style keyboard, for
instance?
> Is there any sniffed data for the HP8200 available? Would anyone be available
> to test a patch to spit out the values of these registers on the HP8200?
I don't know. In fact, I don't know of anyone who has the HP8200.
> Also, Alan, I did some reading up about ATA/ATAPI. If I understand it right,
> ATA was only for hard disks, and ATAPI came later to support CD drives, etc.
That's right.
> This means that both the HP8200 and the flash devices are ATAPI.
If you say so. But...
> Interesting.. After executing IDENTIFY PACKET DEVICE (0xA1), the flash-usbat02
> returns an error (as indicated by bit 0 in status register) and does not
> produce a high DRQ (bit 3 of status reg) as indicated in the command
> description. So, the flash devices don't appear to support packet commands. Is
> it safe to say that HP8200's *do* support these?
Don't ask me; I know zero about the HP8200. However the shuttle_usbat
driver does seem to use packet commands, according to the comments in the
source code.
Doesn't the fact that the flash version returns an error indicate that
it really _isn't_ ATAPI? And doesn't your driver communicate with the
flash device using regular ATA commands, not ATAPI packet commands?
Alan Stern
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