erl_driver for Enea OSE

20132014 Ericsson AB. All Rights Reserved. The contents of this file are subject to the Erlang Public License, Version 1.1, (the "License"); you may not use this file except in compliance with the License. You should have received a copy of the Erlang Public License along with this software. If not, it can be retrieved online at http://www.erlang.org/. Software distributed under the License is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for the specific language governing rights and limitations under the License. erl_driver for Enea OSE Lukas Larsson 2014-01-08 A ose_erl_driver.xml

ose_erl_driver Linked-in drivers in Enea OSE

Writing Linked-in drivers that also work on Enea OSE is very similar for how you would do it for Unix. The difference from Unix is that driver_select, ready_input and ready_output all work with signals instead of file descriptors. This means that the driver_select is used to specify which type of signal should trigger calls to ready_input/ready_output. The functions described below are available to driver programmers on Enea OSE to facilitate this.

DATA TYPES union SIGNAL See the Enea OSE SPI documentation for a description. SIGSELECT See the Enea OSE SPI documentation for a description. ErlDrvEvent The ErlDrvEvent is a handle to a signal number and id combination. It is passed to driver_select(3). ErlDrvOseEventId This is the id used to associate a specific signal to a certain driver instance.

union SIGNAL *erl_drv_ose_get_signal(ErlDrvEvent drv_event)

Fetch the next signal associated with drv_event. Signals will be returned in the order which they were received and when no more signals are available NULL will be returned. Use this function in the ready_input/ready_output callbacks to get signals.

ErlDrvEventerl_drv_ose_event_alloc(SIGSELECT signo, ErlDrvOseEventId id, ErlDrvOseEventId (*resolve_signal)(union SIGNAL* sig), void *extra)

Create a new ErlDrvEvent associated with signo, id and uses the resolve_signal function to extract the id from a signal with signo. The extra parameter can be used for additional data. See Signals in a Linked-in driver in the OSE User's Guide.

voiderl_drv_ose_event_free(ErlDrvEvent drv_event)

Free a ErlDrvEvent. This should always be done in the stop_select callback when the event is no longer being used.

voiderl_drv_ose_event_fetch(ErlDrvEvent drv_event, SIGSELECT *signo, ErlDrvOseEventId *id, void **extra)

Write the signal number, id and any extra data associated with drv_event into *signo and *id respectively. NULL can be also passed as signo or id in order to ignore that field.