Based on kernel version 4.15. Page generated on 2018-01-29 10:01 EST.
1 ==================================== 2 SGI IOC4 PCI (multi function) device 3 ==================================== 4 5 The SGI IOC4 PCI device is a bit of a strange beast, so some notes on 6 it are in order. 7 8 First, even though the IOC4 performs multiple functions, such as an 9 IDE controller, a serial controller, a PS/2 keyboard/mouse controller, 10 and an external interrupt mechanism, it's not implemented as a 11 multifunction device. The consequence of this from a software 12 standpoint is that all these functions share a single IRQ, and 13 they can't all register to own the same PCI device ID. To make 14 matters a bit worse, some of the register blocks (and even registers 15 themselves) present in IOC4 are mixed-purpose between these several 16 functions, meaning that there's no clear "owning" device driver. 17 18 The solution is to organize the IOC4 driver into several independent 19 drivers, "ioc4", "sgiioc4", and "ioc4_serial". Note that there is no 20 PS/2 controller driver as this functionality has never been wired up 21 on a shipping IO card. 22 23 ioc4 24 ==== 25 This is the core (or shim) driver for IOC4. It is responsible for 26 initializing the basic functionality of the chip, and allocating 27 the PCI resources that are shared between the IOC4 functions. 28 29 This driver also provides registration functions that the other 30 IOC4 drivers can call to make their presence known. Each driver 31 needs to provide a probe and remove function, which are invoked 32 by the core driver at appropriate times. The interface of these 33 IOC4 function probe and remove operations isn't precisely the same 34 as PCI device probe and remove operations, but is logically the 35 same operation. 36 37 sgiioc4 38 ======= 39 This is the IDE driver for IOC4. Its name isn't very descriptive 40 simply for historical reasons (it used to be the only IOC4 driver 41 component). There's not much to say about it other than it hooks 42 up to the ioc4 driver via the appropriate registration, probe, and 43 remove functions. 44 45 ioc4_serial 46 =========== 47 This is the serial driver for IOC4. There's not much to say about it 48 other than it hooks up to the ioc4 driver via the appropriate registration, 49 probe, and remove functions.