From: Ruslan Ruslichenko <Ruslan_Ruslichenko@epam.com>

Add a mechanism to defer device initialization
until after the main FDT traversal.

This introduces a deferred queue in FDTMachineInfo.
Devices in this queue are processed in fdt_init_deferred(),
which handles their realization, reset registration,
and resource parsing (interrupts and memory regions).

This allows resolving initialization where devices need to
be realized on latest stages or outside of co-routine context.

Signed-off-by: Ruslan Ruslichenko <Ruslan_Ruslichenko@epam.com>
---
 hw/core/fdt_generic_util.c    | 28 ++++++++++++++++++++++++++++
 include/hw/core/fdt_generic.h |  8 ++++++++
 2 files changed, 36 insertions(+)

diff --git a/hw/core/fdt_generic_util.c b/hw/core/fdt_generic_util.c
index c92b5c287b..ae54ada11d 100644
--- a/hw/core/fdt_generic_util.c
+++ b/hw/core/fdt_generic_util.c
@@ -93,6 +93,13 @@ static bool qemu_irq_shared_or_handler(bool *inputs, int n)
     return false;
 }
 
+static void fdt_parse_node_reg_prop(FDTMachineInfo *fdti, char *node_path,
+                             Object *dev);
+static void fdt_parse_node_irq_prop(FDTMachineInfo *fdti, char *node_path,
+                             Object *dev);
+static void fdt_init_device_realize(FDTMachineInfo *fdti,  char *node_path,
+                                   Object *dev);
+
 static void qemu_irq_shared_handler(void *opaque, int n, int level)
 {
     QEMUIRQSharedState *s = opaque;
@@ -162,6 +169,26 @@ static void fdt_init_cpu_clusters(FDTMachineInfo *fdti)
     }
 }
 
+static void fdt_init_deferred(FDTMachineInfo *fdti)
+{
+    while (fdti->deferred) {
+        FDTDeferredNode *dnode = fdti->deferred;
+
+        fdt_debug("FDT: Deferred realize node: %s\n",
+                 dnode->node_path);
+
+        fdt_init_device_realize(fdti, dnode->node_path, OBJECT(dnode->dev));
+
+        fdt_parse_node_reg_prop(fdti, dnode->node_path, OBJECT(dnode->dev));
+
+        fdt_parse_node_irq_prop(fdti, dnode->node_path, OBJECT(dnode->dev));
+
+        fdti->deferred = dnode->next;
+        g_free(dnode->node_path);
+        g_free(dnode);
+    }
+}
+
 FDTMachineInfo *fdt_generic_create_machine(void *fdt, qemu_irq *cpu_irq)
 {
     FDTMachineInfo *fdti = fdt_init_new_fdti(fdt);
@@ -175,6 +202,7 @@ FDTMachineInfo *fdt_generic_create_machine(void *fdt, qemu_irq *cpu_irq)
     while (qemu_co_enter_next(fdti->cq, NULL)) {
         ;
     }
+    fdt_init_deferred(fdti);
     fdt_init_cpu_clusters(fdti);
     fdt_init_all_irqs(fdti);
     memory_region_transaction_commit();
diff --git a/include/hw/core/fdt_generic.h b/include/hw/core/fdt_generic.h
index 3961615a9c..2d507392fa 100644
--- a/include/hw/core/fdt_generic.h
+++ b/include/hw/core/fdt_generic.h
@@ -35,6 +35,12 @@ typedef struct FDTIRQConnection {
     void *next;
 } FDTIRQConnection;
 
+typedef struct FDTDeferredNode {
+    DeviceState *dev;
+    char *node_path;
+    void *next;
+} FDTDeferredNode;
+
 typedef struct FDTMachineInfo {
     /* the fdt blob */
     void *fdt;
@@ -48,6 +54,8 @@ typedef struct FDTMachineInfo {
     FDTIRQConnection *irqs;
     /* list of all CPU clusters */
     FDTCPUCluster *clusters;
+    /* list of devices for deferred init */
+    FDTDeferredNode *deferred;
 } FDTMachineInfo;
 
 /*
-- 
2.43.0