Unlike most other device drivers, the FCP adapter device driver does not support the read and write subroutines. It only supports the open, close, ioctl, config, and strategy subroutines. Included with the open subroutine call is the openx subroutine that allows FCP adapter diagnostics.
A FCP device driver does not need to access the FCP diagnostic commands. Commands received from the device driver through the strategy routine of the adapter are processed from a queue. Once the command has completed, the device driver is notified through the iodone kernel service.
To continue reading specific information about interfaces to the adapter driver and the device driver, see FCP Adapter/Device Interface.