IOS is the operating system that runs on the Starlet coprocessor inside the Hollywood package. It provides the services that are used by Wii code to access most of the system devices.
See also: IOS/QA
Communication with IOS from PPC code is done using an IPC mechanism. There are 7 calls that can be made using this system:
Here is a sample implementation, not guaranteed to work: ipc.c
ipc struct size = 40, aligned to 20 00: cmd // 1=open 2=close 3=read 4=write 5=seek 6=ioctl 7=ioctlv 04: ret 08: fd 0c: arg 20: async1 24: async2 28: 0 40: relaunch, used for ioctlvreboot open: fd = 0 arg0, arg1: name, mode (1=read 2=write) close: fd read: fd arg0, arg1: addr, len write: fd arg0, arg1: addr, len seek: fd arg0, arg1: where, whence ioctl: fd arg0: ioctl # arg1, arg2: addr, len arg3, arg4: addr, len ioctlv: fd arg0: ioctl # arg1: # in arg2: # out (or in-out) arg3: pointer to # in plus # out pairs of (addr, len)
fd is a handle you get back from ios on "open", and that you should pass back to all other calls --segher
Most non-trivial operations are performed by opening one of the below resources, then calling ioctl or ioctlv on it.
The Starlet kernel hands these calls over to the individual drivers / processes within the Starlet. The processes register themselves to handle requests by creating one or more queues and assigning them to handle requests from a particular /dev device.
For testing out IOS devices, you can use the EasyIOS application for the wii.
Known resources in the /dev tree:
- /dev/net/ip/top - TCP/IP Socket operations