[Qemu-devel] [PATCH v6 3/9] qdev: add clock input&output support to devices.

[damien.hedde@greensocs.con]

From: Damien Hedde <damien.hedde@greensocs.com>

Add functions to easily add input or output clocks to a device.
A clock objects is added as a child of the device.
The api is very similar the gpio's one.

This is based on the original work of Frederic Konrad.

Signed-off-by: Damien Hedde <damien.hedde@greensocs.com>

---
I've removed the reviewed-by/tested-by of Philippe because I did a small
modification.

qdev_connect_clock() which allowed to connect an input to an output is
now split in 2:
+ qdev_get_clock_in() which gets a given input from a device
+ qdev_connect_clock_out() which connect a given output to a clock
(previously fetched by qdev_get_clock_in())
This part is located in (qdev-clock.[c|h]).
It better matches gpios api and also add the possibility to connect a
device's input clock to a random output clock (used in patch 9).

Also add missing qdev-clock in the test-qdev-global-props so that tests
pass.
---
 hw/core/Makefile.objs   |   2 +-
 hw/core/qdev-clock.c    | 155 ++++++++++++++++++++++++++++++++++++++++
 hw/core/qdev.c          |  32 +++++++++
 include/hw/qdev-clock.h |  67 +++++++++++++++++
 include/hw/qdev-core.h  |  14 ++++
 tests/Makefile.include  |   1 +
 6 files changed, 270 insertions(+), 1 deletion(-)
 create mode 100644 hw/core/qdev-clock.c
 create mode 100644 include/hw/qdev-clock.h

diff --git a/hw/core/Makefile.objs b/hw/core/Makefile.objs
index 8fcebf2e67..4523d3b5c7 100644
--- a/hw/core/Makefile.objs
+++ b/hw/core/Makefile.objs
@@ -1,5 +1,5 @@
 # core qdev-related obj files, also used by *-user:
-common-obj-y += qdev.o qdev-properties.o
+common-obj-y += qdev.o qdev-properties.o qdev-clock.o
 common-obj-y += bus.o reset.o
 common-obj-y += resettable.o
 common-obj-$(CONFIG_SOFTMMU) += qdev-fw.o
diff --git a/hw/core/qdev-clock.c b/hw/core/qdev-clock.c
new file mode 100644
index 0000000000..bebdd8fa15
--- /dev/null
+++ b/hw/core/qdev-clock.c
@@ -0,0 +1,155 @@
+/*
+ * Device's clock
+ *
+ * Copyright GreenSocs 2016-2018
+ *
+ * Authors:
+ *  Frederic Konrad <fred.konrad@greensocs.com>
+ *  Damien Hedde <damien.hedde@greensocs.com>
+ *
+ * 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/qdev-clock.h"
+#include "hw/qdev-core.h"
+#include "qapi/error.h"
+
+static NamedClockList *qdev_init_clocklist(DeviceState *dev, const char *name,
+        bool forward)
+{
+    NamedClockList *ncl;
+
+    /*
+     * The clock path will be computed by the device's realize function call.
+     * This is required to ensure the clock's canonical path is right and log
+     * messages are meaningfull.
+     */
+    assert(name);
+    assert(!dev->realized);
+
+    /* The ncl structure will be freed in device's finalize function call */
+    ncl = g_malloc0(sizeof(*ncl));
+    ncl->name = g_strdup(name);
+    ncl->forward = forward;
+
+    QLIST_INSERT_HEAD(&dev->clocks, ncl, node);
+    return ncl;
+}
+
+ClockOut *qdev_init_clock_out(DeviceState *dev, const char *name)
+{
+    NamedClockList *ncl;
+    Object *clk;
+
+    ncl = qdev_init_clocklist(dev, name, false);
+
+    clk = object_new(TYPE_CLOCK_OUT);
+
+    /* will fail if name already exists */
+    object_property_add_child(OBJECT(dev), name, clk, &error_abort);
+    object_unref(clk); /* remove the initial ref made by object_new */
+
+    ncl->out = CLOCK_OUT(clk);
+    return ncl->out;
+}
+
+ClockIn *qdev_init_clock_in(DeviceState *dev, const char *name,
+                        ClockCallback *callback, void *opaque)
+{
+    NamedClockList *ncl;
+    Object *clk;
+
+    ncl = qdev_init_clocklist(dev, name, false);
+
+    clk = object_new(TYPE_CLOCK_IN);
+    /*
+     * the ref initialized by object_new will be cleared during dev finalize.
+     * It allows us to safely remove the callback.
+     */
+
+    /* will fail if name already exists */
+    object_property_add_child(OBJECT(dev), name, clk, &error_abort);
+
+    ncl->in = CLOCK_IN(clk);
+    if (callback) {
+        clock_set_callback(ncl->in, callback, opaque);
+    }
+    return ncl->in;
+}
+
+static NamedClockList *qdev_get_clocklist(DeviceState *dev, const char *name)
+{
+    NamedClockList *ncl;
+
+    QLIST_FOREACH(ncl, &dev->clocks, node) {
+        if (strcmp(name, ncl->name) == 0) {
+            return ncl;
+        }
+    }
+
+    return NULL;
+}
+
+void qdev_pass_clock(DeviceState *dev, const char *name,
+                     DeviceState *container, const char *cont_name)
+{
+    NamedClockList *original_ncl, *ncl;
+    Object **clk;
+
+    assert(container && cont_name);
+
+    original_ncl = qdev_get_clocklist(container, cont_name);
+    assert(original_ncl); /* clock must exist in origin */
+
+    ncl = qdev_init_clocklist(dev, name, true);
+
+    if (ncl->out) {
+        clk = (Object **)&ncl->out;
+    } else {
+        clk = (Object **)&ncl->in;
+    }
+
+    /* will fail if name already exists */
+    object_property_add_link(OBJECT(dev), name, object_get_typename(*clk),
+                             clk, NULL, OBJ_PROP_LINK_STRONG, &error_abort);
+}
+
+ClockIn *qdev_get_clock_in(DeviceState *dev, const char *name)
+{
+    NamedClockList *ncl;
+
+    assert(dev && name);
+
+    ncl = qdev_get_clocklist(dev, name);
+    return ncl ? ncl->in : NULL;
+}
+
+static ClockOut *qdev_get_clock_out(DeviceState *dev, const char *name)
+{
+    NamedClockList *ncl;
+
+    assert(dev && name);
+
+    ncl = qdev_get_clocklist(dev, name);
+    return ncl ? ncl->out : NULL;
+}
+
+void qdev_connect_clock_out(DeviceState *dev, const char *name, ClockIn *clk,
+                            Error **errp)
+{
+    ClockOut *clkout = qdev_get_clock_out(dev, name);
+
+    if (!clk) {
+        error_setg(errp, "NULL input clock");
+        return;
+    }
+
+    if (!clkout) {
+        error_setg(errp, "no output clock '%s' in device", name);
+        return;
+    }
+
+    clock_connect(clk, clkout);
+}
diff --git a/hw/core/qdev.c b/hw/core/qdev.c
index 9095f2b9c1..eae6cd3e09 100644
--- a/hw/core/qdev.c
+++ b/hw/core/qdev.c
@@ -37,6 +37,7 @@
 #include "hw/qdev-properties.h"
 #include "hw/boards.h"
 #include "hw/sysbus.h"
+#include "hw/clock.h"
 #include "migration/vmstate.h"
 
 bool qdev_hotplug = false;
@@ -821,6 +822,7 @@ static void device_set_realized(Object *obj, bool value, Error **errp)
     DeviceClass *dc = DEVICE_GET_CLASS(dev);
     HotplugHandler *hotplug_ctrl;
     BusState *bus;
+    NamedClockList *clk;
     Error *local_err = NULL;
     bool unattached_parent = false;
     static int unattached_count;
@@ -869,6 +871,15 @@ static void device_set_realized(Object *obj, bool value, Error **errp)
          */
         g_free(dev->canonical_path);
         dev->canonical_path = object_get_canonical_path(OBJECT(dev));
+        QLIST_FOREACH(clk, &dev->clocks, node) {
+            if (clk->forward) {
+                continue;
+            } else if (clk->in != NULL) {
+                clock_in_setup_canonical_path(clk->in);
+            } else {
+                clock_out_setup_canonical_path(clk->out);
+            }
+        }
 
         if (qdev_get_vmsd(dev)) {
             if (vmstate_register_with_alias_id(dev, -1, qdev_get_vmsd(dev), dev,
@@ -999,6 +1010,7 @@ static void device_initfn(Object *obj)
                              (Object **)&dev->parent_bus, NULL, 0,
                              &error_abort);
     QLIST_INIT(&dev->gpios);
+    QLIST_INIT(&dev->clocks);
 }
 
 static void device_post_init(Object *obj)
@@ -1015,6 +1027,7 @@ static void device_post_init(Object *obj)
 static void device_finalize(Object *obj)
 {
     NamedGPIOList *ngl, *next;
+    NamedClockList *clk, *clk_next;
 
     DeviceState *dev = DEVICE(obj);
 
@@ -1028,6 +1041,25 @@ static void device_finalize(Object *obj)
          */
     }
 
+    QLIST_FOREACH_SAFE(clk, &dev->clocks, node, clk_next) {
+        QLIST_REMOVE(clk, node);
+        if (!clk->forward && clk->in) {
+            /*
+             * if this clock is not forwarded, clk->in is a child of dev.
+             * At this point the child property and associated reference is
+             * already deleted but we kept a ref on clk->in to ensure it lives
+             * up to this point and we can safely remove the callback.
+             * It avoids having a lost callback to a deleted device if the
+             * clk->in is still referenced somewhere else (eg: by a clock
+             * output).
+             */
+            clock_clear_callback(clk->in);
+            object_unref(OBJECT(clk->in));
+        }
+        g_free(clk->name);
+        g_free(clk);
+    }
+
     /* Only send event if the device had been completely realized */
     if (dev->pending_deleted_event) {
         g_assert(dev->canonical_path);
diff --git a/include/hw/qdev-clock.h b/include/hw/qdev-clock.h
new file mode 100644
index 0000000000..c4ea912fdc
--- /dev/null
+++ b/include/hw/qdev-clock.h
@@ -0,0 +1,67 @@
+#ifndef QDEV_CLOCK_H
+#define QDEV_CLOCK_H
+
+#include "hw/clock.h"
+
+/**
+ * qdev_init_clock_in:
+ * @dev: the device in which to add a clock
+ * @name: the name of the clock (can't be NULL).
+ * @callback: optional callback to be called on update or NULL.
+ * @opaque:   argument for the callback
+ * @returns: a pointer to the newly added clock
+ *
+ * Add a input clock to device @dev as a clock named @name.
+ * This adds a child<> property.
+ * The callback will be called with @dev as opaque parameter.
+ */
+ClockIn *qdev_init_clock_in(DeviceState *dev, const char *name,
+                            ClockCallback *callback, void *opaque);
+
+/**
+ * qdev_init_clock_out:
+ * @dev: the device to add a clock to
+ * @name: the name of the clock (can't be NULL).
+ * @callback: optional callback to be called on update or NULL.
+ * @returns: a pointer to the newly added clock
+ *
+ * Add a output clock to device @dev as a clock named @name.
+ * This adds a child<> property.
+ */
+ClockOut *qdev_init_clock_out(DeviceState *dev, const char *name);
+
+/**
+ * qdev_get_clock_in:
+ * @dev: the device which has the clock
+ * @name: the name of the clock (can't be NULL).
+ * @returns: a pointer to the clock
+ *
+ * Get the clock @name from @dev or NULL if does not exists.
+ */
+ClockIn *qdev_get_clock_in(DeviceState *dev, const char *name);
+
+/**
+ * qdev_connect_clock_out:
+ * @dev: the device which has the clock
+ * @name: the name of the clock (can't be NULL).
+ * @errp: error report
+ *
+ * Connect @clk to the output clock @name of @dev.
+ * Reports an error if clk is NULL or @name does not exists in @dev.
+ */
+void qdev_connect_clock_out(DeviceState *dev, const char *name, ClockIn *clk,
+                            Error **errp);
+
+/**
+ * qdev_pass_clock:
+ * @dev: the device to forward the clock to
+ * @name: the name of the clock to be added (can't be NULL)
+ * @container: the device which already has the clock
+ * @cont_name: the name of the clock in the container device
+ *
+ * Add a clock @name to @dev which forward to the clock @cont_name in @container
+ */
+void qdev_pass_clock(DeviceState *dev, const char *name,
+                     DeviceState *container, const char *cont_name);
+
+#endif /* QDEV_CLOCK_H */
diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h
index eb11f0f801..60a65f6142 100644
--- a/include/hw/qdev-core.h
+++ b/include/hw/qdev-core.h
@@ -131,6 +131,19 @@ struct NamedGPIOList {
     QLIST_ENTRY(NamedGPIOList) node;
 };
 
+typedef struct NamedClockList NamedClockList;
+
+typedef struct ClockIn ClockIn;
+typedef struct ClockOut ClockOut;
+
+struct NamedClockList {
+    char *name;
+    bool forward;
+    ClockIn *in;
+    ClockOut *out;
+    QLIST_ENTRY(NamedClockList) node;
+};
+
 /**
  * DeviceState:
  * @realized: Indicates whether the device has been fully constructed.
@@ -152,6 +165,7 @@ struct DeviceState {
     int hotplugged;
     BusState *parent_bus;
     QLIST_HEAD(, NamedGPIOList) gpios;
+    QLIST_HEAD(, NamedClockList) clocks;
     QLIST_HEAD(, BusState) child_bus;
     int num_child_bus;
     int instance_id_alias;
diff --git a/tests/Makefile.include b/tests/Makefile.include
index f0b4628cc6..5c54beb29e 100644
--- a/tests/Makefile.include
+++ b/tests/Makefile.include
@@ -566,6 +566,7 @@ tests/test-qdev-global-props$(EXESUF): tests/test-qdev-global-props.o \
 	hw/core/irq.o \
 	hw/core/fw-path-provider.o \
 	hw/core/reset.o \
+	hw/core/clock.o \
 	$(test-qapi-obj-y)
 tests/test-vmstate$(EXESUF): tests/test-vmstate.o \
 	migration/vmstate.o migration/vmstate-types.o migration/qemu-file.o \
-- 
2.22.0