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Possible License(s): CC-BY-SA-3.0, GPL-2.0, LGPL-2.0, AGPL-1.0
 1The SGI IOC4 PCI device is a bit of a strange beast, so some notes on
 2it are in order.
 4First, even though the IOC4 performs multiple functions, such as an
 5IDE controller, a serial controller, a PS/2 keyboard/mouse controller,
 6and an external interrupt mechanism, it's not implemented as a
 7multifunction device.  The consequence of this from a software
 8standpoint is that all these functions share a single IRQ, and
 9they can't all register to own the same PCI device ID.  To make
10matters a bit worse, some of the register blocks (and even registers
11themselves) present in IOC4 are mixed-purpose between these several
12functions, meaning that there's no clear "owning" device driver.
14The solution is to organize the IOC4 driver into several independent
15drivers, "ioc4", "sgiioc4", and "ioc4_serial".  Note that there is no
16PS/2 controller driver as this functionality has never been wired up
17on a shipping IO card.
21This is the core (or shim) driver for IOC4.  It is responsible for
22initializing the basic functionality of the chip, and allocating
23the PCI resources that are shared between the IOC4 functions.
25This driver also provides registration functions that the other
26IOC4 drivers can call to make their presence known.  Each driver
27needs to provide a probe and remove function, which are invoked
28by the core driver at appropriate times.  The interface of these
29IOC4 function probe and remove operations isn't precisely the same
30as PCI device probe and remove operations, but is logically the
31same operation.
35This is the IDE driver for IOC4.  Its name isn't very descriptive
36simply for historical reasons (it used to be the only IOC4 driver
37component).  There's not much to say about it other than it hooks
38up to the ioc4 driver via the appropriate registration, probe, and
39remove functions.
43This is the serial driver for IOC4.  There's not much to say about it
44other than it hooks up to the ioc4 driver via the appropriate registration,
45probe, and remove functions.