- Additionally adds special token - abstract "iocookie" structure
to control/identifies/manage I/Os, by passing it to OS.
Actual type of "iocookie" could be arch-specific. Device drivers
could use the iocookie structure without knowing its detail.
I'm not sure we need this. Surely it can be deduced from the pci_dev or
struct device?
Might be useful to know more though, wether it was PIO or MMIO or other
things. Also, I'd like to carry around the possible error details as can
be returned by the firmware in some platforms.
In fact, Is there any reason this is not ioerr_cookie instead of
iocookie ? :)