[Qemu-devel] [PATCH v4 08/10] hw/core/resettable: add support for warm reset

[Damien Hedde <damien.hedde@greensocs.com>]

Add the RESET_TYPE_WARM reset type.
Expand the actual implementation to support several types.

I used values which can be or'ed together. This way we can what reset
has been triggered.

Documentation is added in a following patch.

Signed-off-by: Damien Hedde <damien.hedde@greensocs.com>
---
 hw/core/resettable.c    | 25 +++++++++++++++++++------
 include/hw/resettable.h | 22 +++++++++++++++++-----
 2 files changed, 36 insertions(+), 11 deletions(-)

diff --git a/hw/core/resettable.c b/hw/core/resettable.c
index b534c2c7a4..80674292b3 100644
--- a/hw/core/resettable.c
+++ b/hw/core/resettable.c
@@ -34,12 +34,17 @@ static void resettable_init_reset(Object *obj, ResetType type)
     ResetState *s = rc->get_state(obj);
     bool action_needed = false;
 
-    /* Only take action if we really enter reset for the 1st time. */
+    /* ensure type is empty if no reset is in progress */
+    if (s->count == 0) {
+        s->type = 0;
+    }
+
     /*
-     * TODO: if adding more ResetType support, some additional checks
-     * are probably needed here.
+     * Only take action if:
+     * + we are not already in cold reset,
+     * + and we enter a new type of reset.
      */
-    if (s->count == 0) {
+    if ((s->type & RESET_TYPE_COLD) == 0 && (s->type & type) == 0) {
         action_needed = true;
     }
     s->count += 1;
@@ -62,6 +67,7 @@ static void resettable_init_reset(Object *obj, ResetType type)
 
     /* exec init phase */
     if (action_needed) {
+        s->type |= type;
         s->hold_phase_needed = true;
         if (rc->phases.init) {
             rc->phases.init(obj, type);
@@ -133,8 +139,7 @@ static void resettable_exit_reset(Object *obj)
 
 void resettable_reset(Object *obj, ResetType type)
 {
-    /* TODO: change that when adding support for other reset types */
-    assert(type == RESET_TYPE_COLD);
+    assert(type == RESET_TYPE_COLD || type == RESET_TYPE_WARM);
     trace_resettable_reset(obj, type);
     resettable_init_reset(obj, type);
     resettable_hold_reset(obj);
@@ -154,6 +159,14 @@ bool resettable_is_resetting(Object *obj)
     return (s->count > 0);
 }
 
+ResetType resettable_get_type(Object *obj)
+{
+    ResettableClass *rc = RESETTABLE_GET_CLASS(obj);
+    ResetState *s = rc->get_state(obj);
+
+    return s->type;
+}
+
 void resettable_class_set_parent_phases(ResettableClass *rc,
                                         ResettableInitPhase init,
                                         ResettableHoldPhase hold,
diff --git a/include/hw/resettable.h b/include/hw/resettable.h
index 5808c3c187..1e77cbd75b 100644
--- a/include/hw/resettable.h
+++ b/include/hw/resettable.h
@@ -12,15 +12,14 @@ typedef struct ResetState ResetState;
 
 /**
  * ResetType:
- * Types of reset.
+ * Types of reset, values can be OR'ed together.
  *
  * + Cold: reset resulting from a power cycle of the object.
- *
- * TODO: Support has to be added to handle more types. In particular,
- * ResetState structure needs to be expanded.
+ * + Warm: reset without power cycling.
  */
 typedef enum ResetType {
-    RESET_TYPE_COLD,
+    RESET_TYPE_COLD = 0x1,
+    RESET_TYPE_WARM = 0x2,
 } ResetType;
 
 /*
@@ -107,11 +106,13 @@ typedef struct ResettablePhases ResettablePhases;
  *
  * @count: Number of reset level the object is into. It is incremented when
  * the reset operation starts and decremented when it finishes.
+ * @type: Type of the in-progress reset. Valid only when count is non-zero.
  * @hold_phase_needed: flag which indicates that we need to invoke the 'hold'
  * phase handler for this object.
  */
 struct ResetState {
     uint32_t count;
+    ResetType type;
     bool hold_phase_needed;
 };
 
@@ -123,6 +124,17 @@ struct ResetState {
  */
 bool resettable_is_resetting(Object *obj);
 
+/**
+ * resettable_get_type:
+ * Return the current type of reset @obj is under.
+ *
+ * @obj must implement Resettable interface. Result is only valid if
+ * @resettable_is_resetting is true.
+ *
+ * Note: this return an OR'ed value of type if several reset were triggered
+ */
+ResetType resettable_get_type(Object *obj);
+
 /**
  * resettable_reset:
  * Trigger a reset on a object @obj of type @type. @obj must implement
-- 
2.22.0