Add a function resettable_change_parent() to do the required
plumbing when changing the parent a of Resettable object.
We need to make sure that the reset state of the object remains
coherent with the reset state of the new parent.
We make the 2 following hypothesis:
+ when an object is put in a parent under reset, the object goes in
reset.
+ when an object is removed from a parent under reset, the object
leaves reset.
The added function avoids any glitch if both old and new parent are
already in reset.
Signed-off-by: Damien Hedde <damien.he...@greensocs.com>
Reviewed-by: Richard Henderson <richard.hender...@linaro.org>
---
include/hw/resettable.h | 16 +++++++++++
hw/core/resettable.c | 62 +++++++++++++++++++++++++++++++++++++++--
hw/core/trace-events | 1 +
3 files changed, 77 insertions(+), 2 deletions(-)
diff --git a/include/hw/resettable.h b/include/hw/resettable.h
index 58b3df4c22..3c87ab86c7 100644
--- a/include/hw/resettable.h
+++ b/include/hw/resettable.h
@@ -194,6 +194,22 @@ void resettable_release_reset(Object *obj, ResetType type);
*/
bool resettable_is_in_reset(Object *obj);
+/**
+ * resettable_change_parent:
+ * Indicate that the parent of Ressettable @obj is changing from @oldp to
@newp.
+ * All 3 objects must implement resettable interface. @oldp or @newp may be
+ * NULL.
+ *
+ * This function will adapt the reset state of @obj so that it is coherent
+ * with the reset state of @newp. It may trigger @resettable_assert_reset()
+ * or @resettable_release_reset(). It will do such things only if the reset
+ * state of @newp and @oldp are different.
+ *
+ * When using this function during reset, it must only be called during
+ * a hold phase method. Calling this during enter or exit phase is an error.
+ */
+void resettable_change_parent(Object *obj, Object *newp, Object *oldp);
+
/**
* resettable_class_set_parent_phases:
*
diff --git a/hw/core/resettable.c b/hw/core/resettable.c
index 9133208487..e99bb30058 100644
--- a/hw/core/resettable.c
+++ b/hw/core/resettable.c
@@ -28,12 +28,16 @@ static void resettable_phase_exit(Object *obj, void
*opaque, ResetType type);
* enter_phase_in_progress:
* True if we are currently in reset enter phase.
*
- * Note: This flag is only used to guarantee (using asserts) that the reset
- * API is used correctly. We can use a global variable because we rely on the
+ * exit_phase_in_progress:
+ * count the number of exit phase we are in.
+ *
+ * Note: These flags are only used to guarantee (using asserts) that the reset
+ * API is used correctly. We can use global variables because we rely on the
* iothread mutex to ensure only one reset operation is in a progress at a
* given time.
*/
static bool enter_phase_in_progress;
+static unsigned exit_phase_in_progress;
void resettable_reset(Object *obj, ResetType type)
{
@@ -65,7 +69,9 @@ void resettable_release_reset(Object *obj, ResetType type)
trace_resettable_reset_release_begin(obj, type);
assert(!enter_phase_in_progress);
+ exit_phase_in_progress += 1;
resettable_phase_exit(obj, NULL, type);
+ exit_phase_in_progress -= 1;
trace_resettable_reset_release_end(obj);
}
@@ -206,6 +212,58 @@ static void resettable_phase_exit(Object *obj, void
*opaque, ResetType type)
trace_resettable_phase_exit_end(obj, obj_typename, s->count);
}
+/*
+ * resettable_get_count:
+ * Get the count of the Resettable object @obj. Return 0 if @obj is NULL.
+ */
+static uint32_t resettable_get_count(Object *obj)
+{
+ if (obj) {
+ ResettableClass *rc = RESETTABLE_GET_CLASS(obj);
+ return rc->get_state(obj)->count;
+ }
+ return 0;
+}
+
+void resettable_change_parent(Object *obj, Object *newp, Object *oldp)
+{
+ ResettableClass *rc = RESETTABLE_GET_CLASS(obj);
+ ResettableState *s = rc->get_state(obj);
+ uint32_t newp_count = resettable_get_count(newp);
+ uint32_t oldp_count = resettable_get_count(oldp);
+
+ /*
+ * Ensure we do not change parent when in enter or exit phase.
+ * During these phases, the reset subtree being updated is partly in reset
+ * and partly not in reset (it depends on the actual position in
+ * resettable_child_foreach()s). We are not able to tell in which part is a
+ * leaving or arriving device. Thus we cannot set the reset count of the
+ * moving device to the proper value.
+ */
+ assert(!enter_phase_in_progress && !exit_phase_in_progress);
+ trace_resettable_change_parent(obj, oldp, oldp_count, newp, newp_count);
+
+ /*
+ * At most one of the two 'for' loops will be executed below
+ * in order to cope with the difference between the two counts.
+ */
+ /* if newp is more reset than oldp */
+ for (uint32_t i = oldp_count; i < newp_count; i++) {
+ resettable_assert_reset(obj, RESET_TYPE_COLD);
+ }
+ /*
+ * if obj is leaving a bus under reset, we need to ensure
+ * hold phase is not pending.
+ */
+ if (oldp_count && s->hold_phase_pending) {
+ resettable_phase_hold(obj, NULL, RESET_TYPE_COLD);
+ }
+ /* if oldp is more reset than newp */
+ for (uint32_t i = newp_count; i < oldp_count; i++) {
+ resettable_release_reset(obj, RESET_TYPE_COLD);
+ }
+}
+
void resettable_class_set_parent_phases(ResettableClass *rc,
ResettableEnterPhase enter,
ResettableHoldPhase hold,
diff --git a/hw/core/trace-events b/hw/core/trace-events
index a2e43f1120..80e6325ab0 100644
--- a/hw/core/trace-events
+++ b/hw/core/trace-events
@@ -16,6 +16,7 @@ resettable_reset_assert_begin(void *obj, int cold) "obj=%p
cold=%d"
resettable_reset_assert_end(void *obj) "obj=%p"
resettable_reset_release_begin(void *obj, int cold) "obj=%p cold=%d"
resettable_reset_release_end(void *obj) "obj=%p"
+resettable_change_parent(void *obj, void *o, uint32_t oc, void *n, uint32_t
nc) "obj=%p from=%p(%" PRIu32 ") to=%p(%" PRIu32 ")"
resettable_phase_enter_begin(void *obj, const char *objtype, uint32_t count,
int type) "obj=%p(%s) count=%" PRIu32 " type=%d"
resettable_phase_enter_exec(void *obj, const char *objtype, int type, int
has_method) "obj=%p(%s) type=%d method=%d"
resettable_phase_enter_end(void *obj, const char *objtype, uint32_t count)
"obj=%p(%s) count=%" PRIu32
--
2.24.1
