[v4,04/10] qdev-clock: introduce an init array to ease the device construction

Commit Message

Damien Hedde Sept. 17, 2018, 8:40 a.m. UTC

From: Damien Hedde <[e-mail]>

Introduce a function and macro helpers to setup several clocks
in a device from a static array description.

An element of the array describes the clock (name and direction) as
well as the related callback and an optional offset to store the
created object pointer in the device state structure.

The array must be terminated by a special element QDEV_CLOCK_END.

This is based on the original work of Frederic Konrad.

Signed-off-by: Damien Hedde <[e-mail]>
---
 include/hw/qdev-clock.h | 67 +++++++++++++++++++++++++++++++++++++++++
 hw/core/qdev-clock.c    | 26 ++++++++++++++++
 2 files changed, 93 insertions(+)

Patch

diff --git a/include/hw/qdev-clock.h b/include/hw/qdev-clock.h
index 324eea6bcc..a5da8878af 100644
--- a/include/hw/qdev-clock.h
+++ b/include/hw/qdev-clock.h
@@ -59,4 +59,71 @@  void qdev_clock_connect(DeviceState *dev, const char *name,
                         DeviceState *driver, const char *driver_name,
                         Error **errp);
 
+/**
+ * ClockInitElem:
+ * @name: name of the clock (can't be NULL)
+ * @output: indicates whether the clock is input or output
+ * @callback: for inputs, optional callback to be called on clock's update
+ * with device as opaque
+ * @offset: optional offset to store the clock pointer in device'state
+ * structure (0 means unused)
+ */
+struct ClockPortInitElem {
+    const char *name;
+    bool output;
+    ClockCallback *callback;
+    size_t offset;
+};
+
+#define clock_offset_value(_type, _devstate, _field) \
+    (offsetof(_devstate, _field) + \
+     type_check(_type *, typeof_field(_devstate, _field)))
+
+#define QDEV_CLOCK(_output, _type, _devstate, _field, _callback) { \
+    .name = (stringify(_field)), \
+    .output = _output, \
+    .callback = _callback, \
+    .offset = clock_offset_value(_type, _devstate, _field), \
+}
+
+/**
+ * QDEV_CLOCK_(IN|OUT):
+ * @_devstate: structure type. @dev argument of qdev_init_clocks below must be
+ * a pointer to that same type.
+ * @_field: a field in @_devstate (must be ClockIn* or ClockOut*)
+ * @_callback: (for input only) callback (or NULL) to be called with the device
+ * state as argument
+ *
+ * The name of the clock will be derived from @_field
+ */
+#define QDEV_CLOCK_IN(_devstate, _field, _callback) \
+    QDEV_CLOCK(false, ClockIn, _devstate, _field, _callback)
+
+#define QDEV_CLOCK_OUT(_devstate, _field) \
+    QDEV_CLOCK(true, ClockOut, _devstate, _field, NULL)
+
+/**
+ * QDEV_CLOCK_IN_NOFIELD:
+ * @_name: name of the clock
+ * @_callback: callback (or NULL) to be called with the device state as argument
+ */
+#define QDEV_CLOCK_IN_NOFIELD(_name, _callback) { \
+    .name = _name, \
+    .output = false, \
+    .callback = _callback, \
+    .offset = 0, \
+}
+
+#define QDEV_CLOCK_END { .name = NULL }
+
+typedef struct ClockPortInitElem ClockPortInitArray[];
+
+/**
+ * qdev_init_clocks:
+ * @dev: the device to add clocks
+ * @clocks: a QDEV_CLOCK_END-terminated array which contains the
+ * clocks information.
+ */
+void qdev_init_clocks(DeviceState *dev, const ClockPortInitArray clocks);
+
 #endif /* QDEV_CLOCK_H */
diff --git a/hw/core/qdev-clock.c b/hw/core/qdev-clock.c
index cb7dba3f75..78d2509e04 100644
--- a/hw/core/qdev-clock.c
+++ b/hw/core/qdev-clock.c
@@ -138,3 +138,29 @@  void qdev_clock_connect(DeviceState *dev, const char *name,
 
     clock_connect(ncl->in , drv_ncl->out);
 }
+
+void qdev_init_clocks(DeviceState *dev, const ClockPortInitArray clocks)
+{
+    const struct ClockPortInitElem *elem;
+
+    assert(dev);
+    assert(clocks);
+
+    for (elem = &clocks[0]; elem->name != NULL; elem++) {
+        /* offset cannot be inside the DeviceState part */
+        assert(elem->offset == 0 || elem->offset > sizeof(DeviceState));
+        if (elem->output) {
+            ClockOut *clk;
+            clk = qdev_init_clock_out(dev, elem->name);
+            if (elem->offset) {
+                *(ClockOut **)(((void *) dev) + elem->offset) = clk;
+            }
+        } else {
+            ClockIn *clk;
+            clk = qdev_init_clock_in(dev, elem->name, elem->callback, dev);
+            if (elem->offset) {
+                *(ClockIn **)(((void *) dev) + elem->offset) = clk;
+            }
+        }
+    }
+}