prom_env.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
#include <sys/promimpl.h>
/*
* The functions in this file are used to control the pre- and post-processing
* functions that bracket calls to the OBP CIF handler. One set, promif_preprom
* and promif_postprom, are provided for general kernel use. The other set,
* promif_preout and promif_postout, are used by the power management subsystem
* to ensure that the framebuffer is active when PROM functions that interact
* with the console are invoked.
*
* In some cases, the operation of these functions must be suppressed. As such,
* this file provides the ability to suspend and resume use of both sets
* simultaneously. Complicating matters is the fact that both current uses of
* the pre- and post-processor suspension and resume facilities, kmdb and CPR
* may be used simultaneously. We therefore support normal operation and two
* levels of suspension. The pre- and post-processing functions are only
* called during normal operation. With each suspension request, this
* subsystem enters the first suspension level, or passes to the second
* suspension level, as appropriate. Resume calls decrement the suspension
* level. Only two nested suspensions are supported.
*
* As indicated above, the two current users are CPR and kmdb. CPR must prevent
* kernel accesses outside of the nucleus page during the late stages of system
* suspension and during the early stages of system resumption. As such, the
* PM-related processing must not occur during these times.
*
* The platform-specific portions of kmdb live in the platmods, and thus execute
* in the linker environment of the platmods. That is, any promif calls they
* may make are executed by the kernel copies of those functions, rather than
* the versions included with kmdb. The only difference between the two copies
* being the nonuse of the pre- and post-processing functions in the kmdb
* versions, we must ensure that these functions are not used when the kmdb
* platmod code executes. Accordingly, kmdb disables the pre- and post-
* processing functions via the KDI prior to passing control to the platmod
* debugger code.
*/
static int promif_suspendlevel;
static promif_preprom_f *promif_preprom_fn;
static promif_postprom_f *promif_postprom_fn;
void
{
}
void
{
}
void
promif_preprom(void)
{
}
void
promif_postprom(void)
{
}
/*
* The reader will note that the layout and calling conventions of the
* prom_preout and prom_postout functions differ from the prom_preprom and
* prom_postprom functions, above. At the time the preout and postout
* functions are initialized, kernel startup is well underway. There exists
* a race condition whereby a PROM call may begin before preout has been
* initialized, and may end after postout has been initialized. In such
* cases, there will be a call to postout without a corresponding preout
* call. The preprom and postprom calls above are initialized early enough
* that this race condition does not occur.
*
* such that the initialization is atomic. Further, the preout call returns
* a data structure that includes a pointer to the postout function that
* corresponds to the invoked preout function. This ensures that the preout
* and postout functions will only be used as a matched set.
*/
static void
null_outfunc(void)
{
}
static promif_owrap_t nullwrapper =
{
};
static promif_owrap_t pmwrapper;
*promif_preout(void)
{
if (promif_suspendlevel > 0)
return (&nullwrapper);
return (ow);
}
void
{
}
void
{
}
void
prom_suspend_prepost(void)
{
}
void
prom_resume_prepost(void)
{
ASSERT(promif_suspendlevel >= 0);
}