3 files changed, 138 insertions, 0 deletions
diff --git a/hw/core/Makefile.objs b/hw/core/Makefile.objs
index 6215e7c208..1d9b0aa205 100644
--- a/hw/core/Makefile.objs
+++ b/hw/core/Makefile.objs
@@ -7,6 +7,7 @@ common-obj-y += hotplug.o
 common-obj-y += vmstate-if.o
 # irq.o needed for qdev GPIO handling:
 common-obj-y += irq.o
+common-obj-y += clock.o
 
 common-obj-$(CONFIG_SOFTMMU) += reset.o
 common-obj-$(CONFIG_SOFTMMU) += qdev-fw.o
diff --git a/hw/core/clock.c b/hw/core/clock.c
new file mode 100644
index 0000000000..3c0daf7d4c
--- /dev/null
+++ b/hw/core/clock.c
@@ -0,0 +1,130 @@
+/*
+ * Hardware Clocks
+ *
+ * Copyright GreenSocs 2016-2020
+ *
+ * Authors:
+ *  Frederic Konrad
+ *  Damien Hedde
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+#include "hw/clock.h"
+#include "trace.h"
+
+#define CLOCK_PATH(_clk) (_clk->canonical_path)
+
+void clock_setup_canonical_path(Clock *clk)
+{
+    g_free(clk->canonical_path);
+    clk->canonical_path = object_get_canonical_path(OBJECT(clk));
+}
+
+void clock_set_callback(Clock *clk, ClockCallback *cb, void *opaque)
+{
+    clk->callback = cb;
+    clk->callback_opaque = opaque;
+}
+
+void clock_clear_callback(Clock *clk)
+{
+    clock_set_callback(clk, NULL, NULL);
+}
+
+void clock_set(Clock *clk, uint64_t period)
+{
+    trace_clock_set(CLOCK_PATH(clk), CLOCK_PERIOD_TO_NS(clk->period),
+                    CLOCK_PERIOD_TO_NS(period));
+    clk->period = period;
+}
+
+static void clock_propagate_period(Clock *clk, bool call_callbacks)
+{
+    Clock *child;
+
+    QLIST_FOREACH(child, &clk->children, sibling) {
+        if (child->period != clk->period) {
+            child->period = clk->period;
+            trace_clock_update(CLOCK_PATH(child), CLOCK_PATH(clk),
+                               CLOCK_PERIOD_TO_NS(clk->period),
+                               call_callbacks);
+            if (call_callbacks && child->callback) {
+                child->callback(child->callback_opaque);
+            }
+            clock_propagate_period(child, call_callbacks);
+        }
+    }
+}
+
+void clock_propagate(Clock *clk)
+{
+    assert(clk->source == NULL);
+    trace_clock_propagate(CLOCK_PATH(clk));
+    clock_propagate_period(clk, true);
+}
+
+void clock_set_source(Clock *clk, Clock *src)
+{
+    /* changing clock source is not supported */
+    assert(!clk->source);
+
+    trace_clock_set_source(CLOCK_PATH(clk), CLOCK_PATH(src));
+
+    clk->period = src->period;
+    QLIST_INSERT_HEAD(&src->children, clk, sibling);
+    clk->source = src;
+    clock_propagate_period(clk, false);
+}
+
+static void clock_disconnect(Clock *clk)
+{
+    if (clk->source == NULL) {
+        return;
+    }
+
+    trace_clock_disconnect(CLOCK_PATH(clk));
+
+    clk->source = NULL;
+    QLIST_REMOVE(clk, sibling);
+}
+
+static void clock_initfn(Object *obj)
+{
+    Clock *clk = CLOCK(obj);
+
+    QLIST_INIT(&clk->children);
+}
+
+static void clock_finalizefn(Object *obj)
+{
+    Clock *clk = CLOCK(obj);
+    Clock *child, *next;
+
+    /* clear our list of children */
+    QLIST_FOREACH_SAFE(child, &clk->children, sibling, next) {
+        clock_disconnect(child);
+    }
+
+    /* remove us from source's children list */
+    clock_disconnect(clk);
+
+    g_free(clk->canonical_path);
+}
+
+static const TypeInfo clock_info = {
+    .name              = TYPE_CLOCK,
+    .parent            = TYPE_OBJECT,
+    .instance_size     = sizeof(Clock),
+    .instance_init     = clock_initfn,
+    .instance_finalize = clock_finalizefn,
+};
+
+static void clock_register_types(void)
+{
+    type_register_static(&clock_info);
+}
+
+type_init(clock_register_types)
diff --git a/hw/core/trace-events b/hw/core/trace-events
index aecd8e160e..1ac60ede6b 100644
--- a/hw/core/trace-events
+++ b/hw/core/trace-events
@@ -27,3 +27,10 @@ resettable_phase_exit_begin(void *obj, const char *objtype, unsigned count, int
 resettable_phase_exit_exec(void *obj, const char *objtype, int has_method) "obj=%p(%s) method=%d"
 resettable_phase_exit_end(void *obj, const char *objtype, unsigned count) "obj=%p(%s) count=%d"
 resettable_transitional_function(void *obj, const char *objtype) "obj=%p(%s)"
+
+# clock.c
+clock_set_source(const char *clk, const char *src) "'%s', src='%s'"
+clock_disconnect(const char *clk) "'%s'"
+clock_set(const char *clk, uint64_t old, uint64_t new) "'%s', ns=%"PRIu64"->%"PRIu64
+clock_propagate(const char *clk) "'%s'"
+clock_update(const char *clk, const char *src, uint64_t val, int cb) "'%s', src='%s', ns=%"PRIu64", cb=%d"