[Qemu-devel] [RFC PATCH 03/11] qemu-clk: allow to bound two clocks together

[fred.konrad@greensocs.com]

From: KONRAD Frederic <fred.konrad@greensocs.com>

This introduces the clock binding and the update part.
When the qemu_clk_rate_update(qemu_clk, int) function is called:
  * The clock callback is called on the qemu_clk so it can change the rate.
  * The qemu_clk_rate_update function is called on all the driven clock.

Signed-off-by: KONRAD Frederic <fred.konrad@greensocs.com>
---
 include/qemu/qemu-clock.h | 65 +++++++++++++++++++++++++++++++++++++++++++++++
 qemu-clock.c              | 56 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 121 insertions(+)

diff --git a/include/qemu/qemu-clock.h b/include/qemu/qemu-clock.h
index a2ba105..677de9a 100644
--- a/include/qemu/qemu-clock.h
+++ b/include/qemu/qemu-clock.h
@@ -27,15 +27,29 @@
 #include "qemu/osdep.h"
 #include "qom/object.h"
 
+typedef float (*qemu_clk_on_rate_update_cb)(void *opaque, float rate);
+
 #define TYPE_CLOCK "qemu-clk"
 #define QEMU_CLOCK(obj) OBJECT_CHECK(struct qemu_clk, (obj), TYPE_CLOCK)
 
+typedef struct ClkList ClkList;
+
 typedef struct qemu_clk {
     /*< private >*/
     Object parent_obj;
     char *name;            /* name of this clock in the device. */
+    float in_rate;         /* rate of the clock which drive this pin. */
+    float out_rate;        /* rate of this clock pin. */
+    void *opaque;
+    qemu_clk_on_rate_update_cb cb;
+    QLIST_HEAD(, ClkList) bound;
 } *qemu_clk;
 
+struct ClkList {
+    qemu_clk clk;
+    QLIST_ENTRY(ClkList) node;
+};
+
 /**
  * qemu_clk_attach_to_device:
  * @d: the device on which the clock need to be attached.
@@ -59,4 +73,55 @@ void qemu_clk_attach_to_device(DeviceState *d, qemu_clk clk,
  */
 qemu_clk qemu_clk_get_pin(DeviceState *d, const char *name);
 
+/**
+ * qemu_clk_bound_clock:
+ * @out: the clock output.
+ * @in: the clock input.
+ *
+ * Connect the clock together. This is unidirectionnal so a
+ * qemu_clk_update_rate will go from @out to @in.
+ *
+ */
+void qemu_clk_bound_clock(qemu_clk out, qemu_clk in);
+
+/**
+ * qemu_clk_unbound:
+ * @out: the clock output.
+ * @in: the clock input.
+ *
+ * Disconnect the clock if they were bound together.
+ *
+ */
+void qemu_clk_unbound(qemu_clk out, qemu_clk in);
+
+/**
+ * qemu_clk_update_rate:
+ * @clk: the clock to update.
+ * @rate: the new rate.
+ *
+ * Update the @clk to the new @rate.
+ *
+ */
+void qemu_clk_update_rate(qemu_clk clk, float rate);
+
+/**
+ * qemu_clk_refresh:
+ * @clk: the clock to be refreshed.
+ *
+ * This updates all childs of a clock without changing its own rate.
+ *
+ */
+void qemu_clk_refresh(qemu_clk clk);
+
+/**
+ * qemu_clk_set_callback:
+ * @clk: the clock where to set the callback.
+ * @cb: the callback to associate to the callback.
+ * @opaque: the opaque data passed to the calback.
+ *
+ */
+void qemu_clk_set_callback(qemu_clk clk,
+                           qemu_clk_on_rate_update_cb cb,
+                           void *opaque);
+
 #endif /* QEMU_CLOCK_H */
diff --git a/qemu-clock.c b/qemu-clock.c
index 81f2852..811d6a0 100644
--- a/qemu-clock.c
+++ b/qemu-clock.c
@@ -34,6 +34,62 @@ do { printf("qemu-clock: " fmt , ## __VA_ARGS__); } while (0)
 #define DPRINTF(fmt, ...) do { } while (0)
 #endif
 
+void qemu_clk_refresh(qemu_clk clk)
+{
+    qemu_clk_update_rate(clk, clk->in_rate);
+}
+
+void qemu_clk_update_rate(qemu_clk clk, float rate)
+{
+    ClkList *child;
+
+    clk->in_rate = rate;
+    clk->out_rate = rate;
+
+    if (clk->cb) {
+        clk->out_rate = clk->cb(clk->opaque, rate);
+    }
+
+    DPRINTF("%s output rate updated to %.1f\n",
+            object_get_canonical_path(OBJECT(clk)),
+            clk->out_rate);
+
+    QLIST_FOREACH(child, &clk->bound, node) {
+        qemu_clk_update_rate(child->clk, clk->out_rate);
+    }
+}
+
+void qemu_clk_bound_clock(qemu_clk out, qemu_clk in)
+{
+    ClkList *child;
+
+    child = g_malloc(sizeof(child));
+    assert(child);
+    child->clk = in;
+    QLIST_INSERT_HEAD(&out->bound, child, node);
+    qemu_clk_update_rate(in, out->out_rate);
+}
+
+void qemu_clk_unbound(qemu_clk out, qemu_clk in)
+{
+    ClkList *child, *next;
+
+    QLIST_FOREACH_SAFE(child, &out->bound, node, next) {
+        if (child->clk == in) {
+            QLIST_REMOVE(child, node);
+            g_free(child);
+        }
+    }
+}
+
+void qemu_clk_set_callback(qemu_clk clk,
+                           qemu_clk_on_rate_update_cb cb,
+                           void *opaque)
+{
+    clk->cb = cb;
+    clk->opaque = opaque;
+}
+
 void qemu_clk_attach_to_device(DeviceState *d, qemu_clk clk, const char *name)
 {
     assert(name);
-- 
2.5.5