1 The SGI IOC4 PCI device is a bit of a strange beast, so some notes on 2 it are in order. 3 4 First, even though the IOC4 performs multiple functions, such as an 5 IDE controller, a serial controller, a PS/2 keyboard/mouse controller, 6 and an external interrupt mechanism, it's not implemented as a 7 multifunction device. The consequence of this from a software 8 standpoint is that all these functions share a single IRQ, and 9 they can't all register to own the same PCI device ID. To make 10 matters a bit worse, some of the register blocks (and even registers 11 themselves) present in IOC4 are mixed-purpose between these several 12 functions, meaning that there's no clear "owning" device driver. 13 14 The solution is to organize the IOC4 driver into several independent 15 drivers, "ioc4", "sgiioc4", and "ioc4_serial". Note that there is no 16 PS/2 controller driver as this functionality has never been wired up 17 on a shipping IO card. 18 19 ioc4 20 ==== 21 This is the core (or shim) driver for IOC4. It is responsible for 22 initializing the basic functionality of the chip, and allocating 23 the PCI resources that are shared between the IOC4 functions. 24 25 This driver also provides registration functions that the other 26 IOC4 drivers can call to make their presence known. Each driver 27 needs to provide a probe and remove function, which are invoked 28 by the core driver at appropriate times. The interface of these 29 IOC4 function probe and remove operations isn't precisely the same 30 as PCI device probe and remove operations, but is logically the 31 same operation. 32 33 sgiioc4 34 ======= 35 This is the IDE driver for IOC4. Its name isn't very descriptive 36 simply for historical reasons (it used to be the only IOC4 driver 37 component). There's not much to say about it other than it hooks 38 up to the ioc4 driver via the appropriate registration, probe, and 39 remove functions. 40 41 ioc4_serial 42 =========== 43 This is the serial driver for IOC4. There's not much to say about it 44 other than it hooks up to the ioc4 driver via the appropriate registration, 45 probe, and remove functions.