301 lines
9.5 KiB
C
301 lines
9.5 KiB
C
/*
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* Resettable interface.
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*
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* Copyright (c) 2019 GreenSocs SAS
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*
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* Authors:
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* Damien Hedde
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*
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* This work is licensed under the terms of the GNU GPL, version 2 or later.
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* See the COPYING file in the top-level directory.
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*/
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#include "qemu/osdep.h"
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#include "qemu/module.h"
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#include "hw/resettable.h"
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#include "trace.h"
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/**
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* resettable_phase_enter/hold/exit:
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* Function executing a phase recursively in a resettable object and its
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* children.
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*/
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static void resettable_phase_enter(Object *obj, void *opaque, ResetType type);
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static void resettable_phase_hold(Object *obj, void *opaque, ResetType type);
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static void resettable_phase_exit(Object *obj, void *opaque, ResetType type);
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/**
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* enter_phase_in_progress:
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* True if we are currently in reset enter phase.
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*
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* exit_phase_in_progress:
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* count the number of exit phase we are in.
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*
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* Note: These flags are only used to guarantee (using asserts) that the reset
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* API is used correctly. We can use global variables because we rely on the
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* iothread mutex to ensure only one reset operation is in a progress at a
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* given time.
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*/
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static bool enter_phase_in_progress;
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static unsigned exit_phase_in_progress;
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void resettable_reset(Object *obj, ResetType type)
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{
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trace_resettable_reset(obj, type);
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resettable_assert_reset(obj, type);
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resettable_release_reset(obj, type);
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}
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void resettable_assert_reset(Object *obj, ResetType type)
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{
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/* TODO: change this assert when adding support for other reset types */
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assert(type == RESET_TYPE_COLD);
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trace_resettable_reset_assert_begin(obj, type);
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assert(!enter_phase_in_progress);
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enter_phase_in_progress = true;
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resettable_phase_enter(obj, NULL, type);
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enter_phase_in_progress = false;
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resettable_phase_hold(obj, NULL, type);
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trace_resettable_reset_assert_end(obj);
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}
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void resettable_release_reset(Object *obj, ResetType type)
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{
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/* TODO: change this assert when adding support for other reset types */
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assert(type == RESET_TYPE_COLD);
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trace_resettable_reset_release_begin(obj, type);
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assert(!enter_phase_in_progress);
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exit_phase_in_progress += 1;
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resettable_phase_exit(obj, NULL, type);
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exit_phase_in_progress -= 1;
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trace_resettable_reset_release_end(obj);
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}
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bool resettable_is_in_reset(Object *obj)
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{
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ResettableClass *rc = RESETTABLE_GET_CLASS(obj);
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ResettableState *s = rc->get_state(obj);
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return s->count > 0;
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}
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/**
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* resettable_child_foreach:
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* helper to avoid checking the existence of the method.
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*/
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static void resettable_child_foreach(ResettableClass *rc, Object *obj,
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ResettableChildCallback cb,
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void *opaque, ResetType type)
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{
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if (rc->child_foreach) {
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rc->child_foreach(obj, cb, opaque, type);
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}
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}
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/**
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* resettable_get_tr_func:
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* helper to fetch transitional reset callback if any.
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*/
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static ResettableTrFunction resettable_get_tr_func(ResettableClass *rc,
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Object *obj)
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{
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ResettableTrFunction tr_func = NULL;
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if (rc->get_transitional_function) {
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tr_func = rc->get_transitional_function(obj);
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}
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return tr_func;
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}
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static void resettable_phase_enter(Object *obj, void *opaque, ResetType type)
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{
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ResettableClass *rc = RESETTABLE_GET_CLASS(obj);
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ResettableState *s = rc->get_state(obj);
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const char *obj_typename = object_get_typename(obj);
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bool action_needed = false;
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/* exit phase has to finish properly before entering back in reset */
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assert(!s->exit_phase_in_progress);
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trace_resettable_phase_enter_begin(obj, obj_typename, s->count, type);
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/* Only take action if we really enter reset for the 1st time. */
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/*
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* TODO: if adding more ResetType support, some additional checks
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* are probably needed here.
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*/
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if (s->count++ == 0) {
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action_needed = true;
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}
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/*
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* We limit the count to an arbitrary "big" value. The value is big
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* enough not to be triggered normally.
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* The assert will stop an infinite loop if there is a cycle in the
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* reset tree. The loop goes through resettable_foreach_child below
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* which at some point will call us again.
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*/
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assert(s->count <= 50);
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/*
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* handle the children even if action_needed is at false so that
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* child counts are incremented too
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*/
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resettable_child_foreach(rc, obj, resettable_phase_enter, NULL, type);
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/* execute enter phase for the object if needed */
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if (action_needed) {
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trace_resettable_phase_enter_exec(obj, obj_typename, type,
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!!rc->phases.enter);
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if (rc->phases.enter && !resettable_get_tr_func(rc, obj)) {
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rc->phases.enter(obj, type);
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}
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s->hold_phase_pending = true;
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}
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trace_resettable_phase_enter_end(obj, obj_typename, s->count);
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}
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static void resettable_phase_hold(Object *obj, void *opaque, ResetType type)
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{
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ResettableClass *rc = RESETTABLE_GET_CLASS(obj);
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ResettableState *s = rc->get_state(obj);
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const char *obj_typename = object_get_typename(obj);
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/* exit phase has to finish properly before entering back in reset */
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assert(!s->exit_phase_in_progress);
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trace_resettable_phase_hold_begin(obj, obj_typename, s->count, type);
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/* handle children first */
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resettable_child_foreach(rc, obj, resettable_phase_hold, NULL, type);
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/* exec hold phase */
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if (s->hold_phase_pending) {
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s->hold_phase_pending = false;
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ResettableTrFunction tr_func = resettable_get_tr_func(rc, obj);
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trace_resettable_phase_hold_exec(obj, obj_typename, !!rc->phases.hold);
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if (tr_func) {
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trace_resettable_transitional_function(obj, obj_typename);
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tr_func(obj);
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} else if (rc->phases.hold) {
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rc->phases.hold(obj);
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}
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}
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trace_resettable_phase_hold_end(obj, obj_typename, s->count);
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}
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static void resettable_phase_exit(Object *obj, void *opaque, ResetType type)
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{
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ResettableClass *rc = RESETTABLE_GET_CLASS(obj);
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ResettableState *s = rc->get_state(obj);
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const char *obj_typename = object_get_typename(obj);
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assert(!s->exit_phase_in_progress);
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trace_resettable_phase_exit_begin(obj, obj_typename, s->count, type);
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/* exit_phase_in_progress ensures this phase is 'atomic' */
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s->exit_phase_in_progress = true;
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resettable_child_foreach(rc, obj, resettable_phase_exit, NULL, type);
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assert(s->count > 0);
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if (s->count == 1) {
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trace_resettable_phase_exit_exec(obj, obj_typename, !!rc->phases.exit);
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if (rc->phases.exit && !resettable_get_tr_func(rc, obj)) {
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rc->phases.exit(obj);
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}
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s->count = 0;
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}
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s->exit_phase_in_progress = false;
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trace_resettable_phase_exit_end(obj, obj_typename, s->count);
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}
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/*
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* resettable_get_count:
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* Get the count of the Resettable object @obj. Return 0 if @obj is NULL.
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*/
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static unsigned resettable_get_count(Object *obj)
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{
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if (obj) {
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ResettableClass *rc = RESETTABLE_GET_CLASS(obj);
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return rc->get_state(obj)->count;
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}
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return 0;
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}
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void resettable_change_parent(Object *obj, Object *newp, Object *oldp)
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{
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ResettableClass *rc = RESETTABLE_GET_CLASS(obj);
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ResettableState *s = rc->get_state(obj);
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unsigned newp_count = resettable_get_count(newp);
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unsigned oldp_count = resettable_get_count(oldp);
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/*
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* Ensure we do not change parent when in enter or exit phase.
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* During these phases, the reset subtree being updated is partly in reset
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* and partly not in reset (it depends on the actual position in
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* resettable_child_foreach()s). We are not able to tell in which part is a
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* leaving or arriving device. Thus we cannot set the reset count of the
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* moving device to the proper value.
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*/
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assert(!enter_phase_in_progress && !exit_phase_in_progress);
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trace_resettable_change_parent(obj, oldp, oldp_count, newp, newp_count);
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/*
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* At most one of the two 'for' loops will be executed below
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* in order to cope with the difference between the two counts.
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*/
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/* if newp is more reset than oldp */
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for (unsigned i = oldp_count; i < newp_count; i++) {
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resettable_assert_reset(obj, RESET_TYPE_COLD);
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}
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/*
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* if obj is leaving a bus under reset, we need to ensure
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* hold phase is not pending.
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*/
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if (oldp_count && s->hold_phase_pending) {
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resettable_phase_hold(obj, NULL, RESET_TYPE_COLD);
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}
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/* if oldp is more reset than newp */
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for (unsigned i = newp_count; i < oldp_count; i++) {
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resettable_release_reset(obj, RESET_TYPE_COLD);
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}
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}
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void resettable_cold_reset_fn(void *opaque)
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{
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resettable_reset((Object *) opaque, RESET_TYPE_COLD);
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}
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void resettable_class_set_parent_phases(ResettableClass *rc,
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ResettableEnterPhase enter,
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ResettableHoldPhase hold,
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ResettableExitPhase exit,
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ResettablePhases *parent_phases)
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{
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*parent_phases = rc->phases;
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if (enter) {
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rc->phases.enter = enter;
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}
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if (hold) {
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rc->phases.hold = hold;
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}
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if (exit) {
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rc->phases.exit = exit;
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}
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}
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static const TypeInfo resettable_interface_info = {
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.name = TYPE_RESETTABLE_INTERFACE,
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.parent = TYPE_INTERFACE,
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.class_size = sizeof(ResettableClass),
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};
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static void reset_register_types(void)
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{
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type_register_static(&resettable_interface_info);
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}
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type_init(reset_register_types)
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