diff mbox

[RFC,06/11] introduce fixed-clock

Message ID 1465835259-21449-7-git-send-email-fred.konrad@greensocs.com (mailing list archive)
State New, archived
Headers show

Commit Message

KONRAD Frédéric June 13, 2016, 4:27 p.m. UTC 
From: KONRAD Frederic <fred.konrad@greensocs.com>

This is a fixed clock device.
It justs behave as an empty device with a parametrable output rate.

Signed-off-by: KONRAD Frederic <fred.konrad@greensocs.com>
---
 hw/misc/Makefile.objs         |  2 +
 hw/misc/fixed-clock.c         | 87 +++++++++++++++++++++++++++++++++++++++++++
 include/hw/misc/fixed-clock.h | 30 +++++++++++++++
 3 files changed, 119 insertions(+)
 create mode 100644 hw/misc/fixed-clock.c
 create mode 100644 include/hw/misc/fixed-clock.h

Comments

Alistair Francis July 1, 2016, 11:07 p.m. UTC | #1 
On Mon, Jun 13, 2016 at 9:27 AM,  <fred.konrad@greensocs.com> wrote:
> From: KONRAD Frederic <fred.konrad@greensocs.com>
>
> This is a fixed clock device.
> It justs behave as an empty device with a parametrable output rate.
>
> Signed-off-by: KONRAD Frederic <fred.konrad@greensocs.com>
> ---
>  hw/misc/Makefile.objs         |  2 +
>  hw/misc/fixed-clock.c         | 87 +++++++++++++++++++++++++++++++++++++++++++
>  include/hw/misc/fixed-clock.h | 30 +++++++++++++++
>  3 files changed, 119 insertions(+)
>  create mode 100644 hw/misc/fixed-clock.c
>  create mode 100644 include/hw/misc/fixed-clock.h
>
> diff --git a/hw/misc/Makefile.objs b/hw/misc/Makefile.objs
> index e504463..e8b8855 100644
> --- a/hw/misc/Makefile.objs
> +++ b/hw/misc/Makefile.objs
> @@ -52,3 +52,5 @@ obj-$(CONFIG_MIPS_ITU) += mips_itu.o
>  obj-$(CONFIG_PVPANIC) += pvpanic.o
>  obj-$(CONFIG_EDU) += edu.o
>  obj-$(CONFIG_HYPERV_TESTDEV) += hyperv_testdev.o
> +
> +obj-y += fixed-clock.o
> diff --git a/hw/misc/fixed-clock.c b/hw/misc/fixed-clock.c
> new file mode 100644
> index 0000000..c273a91
> --- /dev/null
> +++ b/hw/misc/fixed-clock.c
> @@ -0,0 +1,87 @@
> +/*
> + * Fixed clock
> + *
> + *  Copyright (C) 2016 : GreenSocs Ltd
> + *      http://www.greensocs.com/ , email: info@greensocs.com
> + *
> + *  Frederic Konrad   <fred.konrad@greensocs.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation, either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License along
> + * with this program; if not, see <http://www.gnu.org/licenses/>.
> + *
> + */
> +
> +#include "qemu/osdep.h"
> +#include "hw/qdev.h"
> +#include "hw/misc/fixed-clock.h"
> +#include "qemu/qemu-clock.h"
> +#include "qapi/error.h"
> +
> +/* #define DEBUG_FIXED_CLOCK */

Don't include this.

> +
> +#ifdef DEBUG_FIXED_CLOCK
> +#define DPRINTF(fmt, ...) \
> +do { printf("fixed-clock: " fmt , ## __VA_ARGS__); } while (0)

It might be better to use __func__ here.

It should also be qemu_log instead of printf().

> +#else
> +#define DPRINTF(fmt, ...) do { } while (0)
> +#endif
> +
> +typedef struct {
> +    DeviceState parent_obj;
> +
> +    uint32_t rate;
> +    struct qemu_clk out;
> +} FixedClock;

Doesn't this need to be in the header file?

> +
> +static Property fixed_clock_properties[] = {
> +    DEFINE_PROP_UINT32("rate", FixedClock, rate, 0),
> +    DEFINE_PROP_END_OF_LIST()
> +};
> +
> +static void fixed_clock_realizefn(DeviceState *d, Error **errp)

dev instead of d

Thanks,

Alistair

> +{
> +    FixedClock *s = FIXED_CLOCK(d);
> +
> +    qemu_clk_update_rate(&s->out, s->rate);
> +}
> +
> +static void fixed_clock_instance_init(Object *obj)
> +{
> +    FixedClock *s = FIXED_CLOCK(obj);
> +
> +    object_initialize(&s->out, sizeof(s->out), TYPE_CLOCK);
> +    qemu_clk_attach_to_device(DEVICE(obj), &s->out, "clk_out");
> +}
> +
> +static void fixed_clock_class_init(ObjectClass *klass, void *data)
> +{
> +    DeviceClass *dc = DEVICE_CLASS(klass);
> +
> +    dc->realize = fixed_clock_realizefn;
> +    dc->props = fixed_clock_properties;
> +}
> +
> +static const TypeInfo fixed_clock_info = {
> +    .name          = TYPE_FIXED_CLOCK,
> +    .parent        = TYPE_DEVICE,
> +    .instance_size = sizeof(FixedClock),
> +    .instance_init = fixed_clock_instance_init,
> +    .class_init    = fixed_clock_class_init,
> +};
> +
> +static void fixed_clock_register_types(void)
> +{
> +    type_register_static(&fixed_clock_info);
> +}
> +
> +type_init(fixed_clock_register_types);
> diff --git a/include/hw/misc/fixed-clock.h b/include/hw/misc/fixed-clock.h
> new file mode 100644
> index 0000000..1376444
> --- /dev/null
> +++ b/include/hw/misc/fixed-clock.h
> @@ -0,0 +1,30 @@
> +/*
> + * Fixed clock
> + *
> + *  Copyright (C) 2016 : GreenSocs Ltd
> + *      http://www.greensocs.com/ , email: info@greensocs.com
> + *
> + *  Frederic Konrad   <fred.konrad@greensocs.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation, either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License along
> + * with this program; if not, see <http://www.gnu.org/licenses/>.
> + *
> + */
> +
> +#ifndef FIXED_CLOCK_H
> +#define FIXED_CLOCK_H
> +
> +#define TYPE_FIXED_CLOCK "fixed-clock"
> +#define FIXED_CLOCK(obj) OBJECT_CHECK(FixedClock, (obj), TYPE_FIXED_CLOCK)
> +
> +#endif /* FIXED_CLOCK_H */
> --
> 2.5.5
>
>
KONRAD Frédéric Aug. 2, 2016, 11:56 a.m. UTC | #2 
Le 02/07/2016 à 01:07, Alistair Francis a écrit :
> On Mon, Jun 13, 2016 at 9:27 AM,  <fred.konrad@greensocs.com> wrote:
>> From: KONRAD Frederic <fred.konrad@greensocs.com>
>>
>> This is a fixed clock device.
>> It justs behave as an empty device with a parametrable output rate.
>>
>> Signed-off-by: KONRAD Frederic <fred.konrad@greensocs.com>
>> ---
>>   hw/misc/Makefile.objs         |  2 +
>>   hw/misc/fixed-clock.c         | 87 +++++++++++++++++++++++++++++++++++++++++++
>>   include/hw/misc/fixed-clock.h | 30 +++++++++++++++
>>   3 files changed, 119 insertions(+)
>>   create mode 100644 hw/misc/fixed-clock.c
>>   create mode 100644 include/hw/misc/fixed-clock.h
>>
>> diff --git a/hw/misc/Makefile.objs b/hw/misc/Makefile.objs
>> index e504463..e8b8855 100644
>> --- a/hw/misc/Makefile.objs
>> +++ b/hw/misc/Makefile.objs
>> @@ -52,3 +52,5 @@ obj-$(CONFIG_MIPS_ITU) += mips_itu.o
>>   obj-$(CONFIG_PVPANIC) += pvpanic.o
>>   obj-$(CONFIG_EDU) += edu.o
>>   obj-$(CONFIG_HYPERV_TESTDEV) += hyperv_testdev.o
>> +
>> +obj-y += fixed-clock.o
>> diff --git a/hw/misc/fixed-clock.c b/hw/misc/fixed-clock.c
>> new file mode 100644
>> index 0000000..c273a91
>> --- /dev/null
>> +++ b/hw/misc/fixed-clock.c
>> @@ -0,0 +1,87 @@
>> +/*
>> + * Fixed clock
>> + *
>> + *  Copyright (C) 2016 : GreenSocs Ltd
>> + *      http://www.greensocs.com/ , email: info@greensocs.com
>> + *
>> + *  Frederic Konrad   <fred.konrad@greensocs.com>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License as published by
>> + * the Free Software Foundation, either version 2 of the License, or
>> + * (at your option) any later version.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> + * GNU General Public License for more details.
>> + *
>> + * You should have received a copy of the GNU General Public License along
>> + * with this program; if not, see <http://www.gnu.org/licenses/>.
>> + *
>> + */
>> +
>> +#include "qemu/osdep.h"
>> +#include "hw/qdev.h"
>> +#include "hw/misc/fixed-clock.h"
>> +#include "qemu/qemu-clock.h"
>> +#include "qapi/error.h"
>> +
>> +/* #define DEBUG_FIXED_CLOCK */
> Don't include this.
>
>> +
>> +#ifdef DEBUG_FIXED_CLOCK
>> +#define DPRINTF(fmt, ...) \
>> +do { printf("fixed-clock: " fmt , ## __VA_ARGS__); } while (0)
> It might be better to use __func__ here.
>
> It should also be qemu_log instead of printf().
>
>> +#else
>> +#define DPRINTF(fmt, ...) do { } while (0)
>> +#endif
>> +
>> +typedef struct {
>> +    DeviceState parent_obj;
>> +
>> +    uint32_t rate;
>> +    struct qemu_clk out;
>> +} FixedClock;
> Doesn't this need to be in the header file?

I think it's not necessary as we get the clock through the API?
>
>> +
>> +static Property fixed_clock_properties[] = {
>> +    DEFINE_PROP_UINT32("rate", FixedClock, rate, 0),
>> +    DEFINE_PROP_END_OF_LIST()
>> +};
>> +
>> +static void fixed_clock_realizefn(DeviceState *d, Error **errp)
> dev instead of d
>
> Thanks,
>
> Alistair
>
>> +{
>> +    FixedClock *s = FIXED_CLOCK(d);
>> +
>> +    qemu_clk_update_rate(&s->out, s->rate);
>> +}
>> +
>> +static void fixed_clock_instance_init(Object *obj)
>> +{
>> +    FixedClock *s = FIXED_CLOCK(obj);
>> +
>> +    object_initialize(&s->out, sizeof(s->out), TYPE_CLOCK);
>> +    qemu_clk_attach_to_device(DEVICE(obj), &s->out, "clk_out");
>> +}
>> +
>> +static void fixed_clock_class_init(ObjectClass *klass, void *data)
>> +{
>> +    DeviceClass *dc = DEVICE_CLASS(klass);
>> +
>> +    dc->realize = fixed_clock_realizefn;
>> +    dc->props = fixed_clock_properties;
>> +}
>> +
>> +static const TypeInfo fixed_clock_info = {
>> +    .name          = TYPE_FIXED_CLOCK,
>> +    .parent        = TYPE_DEVICE,
>> +    .instance_size = sizeof(FixedClock),
>> +    .instance_init = fixed_clock_instance_init,
>> +    .class_init    = fixed_clock_class_init,
>> +};
>> +
>> +static void fixed_clock_register_types(void)
>> +{
>> +    type_register_static(&fixed_clock_info);
>> +}
>> +
>> +type_init(fixed_clock_register_types);
>> diff --git a/include/hw/misc/fixed-clock.h b/include/hw/misc/fixed-clock.h
>> new file mode 100644
>> index 0000000..1376444
>> --- /dev/null
>> +++ b/include/hw/misc/fixed-clock.h
>> @@ -0,0 +1,30 @@
>> +/*
>> + * Fixed clock
>> + *
>> + *  Copyright (C) 2016 : GreenSocs Ltd
>> + *      http://www.greensocs.com/ , email: info@greensocs.com
>> + *
>> + *  Frederic Konrad   <fred.konrad@greensocs.com>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License as published by
>> + * the Free Software Foundation, either version 2 of the License, or
>> + * (at your option) any later version.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> + * GNU General Public License for more details.
>> + *
>> + * You should have received a copy of the GNU General Public License along
>> + * with this program; if not, see <http://www.gnu.org/licenses/>.
>> + *
>> + */
>> +
>> +#ifndef FIXED_CLOCK_H
>> +#define FIXED_CLOCK_H
>> +
>> +#define TYPE_FIXED_CLOCK "fixed-clock"
>> +#define FIXED_CLOCK(obj) OBJECT_CHECK(FixedClock, (obj), TYPE_FIXED_CLOCK)
>> +
>> +#endif /* FIXED_CLOCK_H */
>> --
>> 2.5.5
>>
>>
Alistair Francis Aug. 4, 2016, 12:29 a.m. UTC | #3 
On Tue, Aug 2, 2016 at 4:56 AM, KONRAD Frederic
<fred.konrad@greensocs.com> wrote:
>
>
> Le 02/07/2016 à 01:07, Alistair Francis a écrit :
>>
>> On Mon, Jun 13, 2016 at 9:27 AM,  <fred.konrad@greensocs.com> wrote:
>>>
>>> From: KONRAD Frederic <fred.konrad@greensocs.com>
>>>
>>> This is a fixed clock device.
>>> It justs behave as an empty device with a parametrable output rate.
>>>
>>> Signed-off-by: KONRAD Frederic <fred.konrad@greensocs.com>
>>> ---
>>>   hw/misc/Makefile.objs         |  2 +
>>>   hw/misc/fixed-clock.c         | 87
>>> +++++++++++++++++++++++++++++++++++++++++++
>>>   include/hw/misc/fixed-clock.h | 30 +++++++++++++++
>>>   3 files changed, 119 insertions(+)
>>>   create mode 100644 hw/misc/fixed-clock.c
>>>   create mode 100644 include/hw/misc/fixed-clock.h
>>>
>>> diff --git a/hw/misc/Makefile.objs b/hw/misc/Makefile.objs
>>> index e504463..e8b8855 100644
>>> --- a/hw/misc/Makefile.objs
>>> +++ b/hw/misc/Makefile.objs
>>> @@ -52,3 +52,5 @@ obj-$(CONFIG_MIPS_ITU) += mips_itu.o
>>>   obj-$(CONFIG_PVPANIC) += pvpanic.o
>>>   obj-$(CONFIG_EDU) += edu.o
>>>   obj-$(CONFIG_HYPERV_TESTDEV) += hyperv_testdev.o
>>> +
>>> +obj-y += fixed-clock.o
>>> diff --git a/hw/misc/fixed-clock.c b/hw/misc/fixed-clock.c
>>> new file mode 100644
>>> index 0000000..c273a91
>>> --- /dev/null
>>> +++ b/hw/misc/fixed-clock.c
>>> @@ -0,0 +1,87 @@
>>> +/*
>>> + * Fixed clock
>>> + *
>>> + *  Copyright (C) 2016 : GreenSocs Ltd
>>> + *      http://www.greensocs.com/ , email: info@greensocs.com
>>> + *
>>> + *  Frederic Konrad   <fred.konrad@greensocs.com>
>>> + *
>>> + * This program is free software; you can redistribute it and/or modify
>>> + * it under the terms of the GNU General Public License as published by
>>> + * the Free Software Foundation, either version 2 of the License, or
>>> + * (at your option) any later version.
>>> + *
>>> + * This program is distributed in the hope that it will be useful,
>>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>>> + * GNU General Public License for more details.
>>> + *
>>> + * You should have received a copy of the GNU General Public License
>>> along
>>> + * with this program; if not, see <http://www.gnu.org/licenses/>.
>>> + *
>>> + */
>>> +
>>> +#include "qemu/osdep.h"
>>> +#include "hw/qdev.h"
>>> +#include "hw/misc/fixed-clock.h"
>>> +#include "qemu/qemu-clock.h"
>>> +#include "qapi/error.h"
>>> +
>>> +/* #define DEBUG_FIXED_CLOCK */
>>
>> Don't include this.
>>
>>> +
>>> +#ifdef DEBUG_FIXED_CLOCK
>>> +#define DPRINTF(fmt, ...) \
>>> +do { printf("fixed-clock: " fmt , ## __VA_ARGS__); } while (0)
>>
>> It might be better to use __func__ here.
>>
>> It should also be qemu_log instead of printf().
>>
>>> +#else
>>> +#define DPRINTF(fmt, ...) do { } while (0)
>>> +#endif
>>> +
>>> +typedef struct {
>>> +    DeviceState parent_obj;
>>> +
>>> +    uint32_t rate;
>>> +    struct qemu_clk out;
>>> +} FixedClock;
>>
>> Doesn't this need to be in the header file?
>
>
> I think it's not necessary as we get the clock through the API?

True, I always assumed it was general convention, although I noticed
that the qemu_irq infrastructure does it like this. So I don't think
it matters.

Thanks,

Alistair

>
>>
>>> +
>>> +static Property fixed_clock_properties[] = {
>>> +    DEFINE_PROP_UINT32("rate", FixedClock, rate, 0),
>>> +    DEFINE_PROP_END_OF_LIST()
>>> +};
>>> +
>>> +static void fixed_clock_realizefn(DeviceState *d, Error **errp)
>>
>> dev instead of d
>>
>> Thanks,
>>
>> Alistair
>>
>>> +{
>>> +    FixedClock *s = FIXED_CLOCK(d);
>>> +
>>> +    qemu_clk_update_rate(&s->out, s->rate);
>>> +}
>>> +
>>> +static void fixed_clock_instance_init(Object *obj)
>>> +{
>>> +    FixedClock *s = FIXED_CLOCK(obj);
>>> +
>>> +    object_initialize(&s->out, sizeof(s->out), TYPE_CLOCK);
>>> +    qemu_clk_attach_to_device(DEVICE(obj), &s->out, "clk_out");
>>> +}
>>> +
>>> +static void fixed_clock_class_init(ObjectClass *klass, void *data)
>>> +{
>>> +    DeviceClass *dc = DEVICE_CLASS(klass);
>>> +
>>> +    dc->realize = fixed_clock_realizefn;
>>> +    dc->props = fixed_clock_properties;
>>> +}
>>> +
>>> +static const TypeInfo fixed_clock_info = {
>>> +    .name          = TYPE_FIXED_CLOCK,
>>> +    .parent        = TYPE_DEVICE,
>>> +    .instance_size = sizeof(FixedClock),
>>> +    .instance_init = fixed_clock_instance_init,
>>> +    .class_init    = fixed_clock_class_init,
>>> +};
>>> +
>>> +static void fixed_clock_register_types(void)
>>> +{
>>> +    type_register_static(&fixed_clock_info);
>>> +}
>>> +
>>> +type_init(fixed_clock_register_types);
>>> diff --git a/include/hw/misc/fixed-clock.h
>>> b/include/hw/misc/fixed-clock.h
>>> new file mode 100644
>>> index 0000000..1376444
>>> --- /dev/null
>>> +++ b/include/hw/misc/fixed-clock.h
>>> @@ -0,0 +1,30 @@
>>> +/*
>>> + * Fixed clock
>>> + *
>>> + *  Copyright (C) 2016 : GreenSocs Ltd
>>> + *      http://www.greensocs.com/ , email: info@greensocs.com
>>> + *
>>> + *  Frederic Konrad   <fred.konrad@greensocs.com>
>>> + *
>>> + * This program is free software; you can redistribute it and/or modify
>>> + * it under the terms of the GNU General Public License as published by
>>> + * the Free Software Foundation, either version 2 of the License, or
>>> + * (at your option) any later version.
>>> + *
>>> + * This program is distributed in the hope that it will be useful,
>>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>>> + * GNU General Public License for more details.
>>> + *
>>> + * You should have received a copy of the GNU General Public License
>>> along
>>> + * with this program; if not, see <http://www.gnu.org/licenses/>.
>>> + *
>>> + */
>>> +
>>> +#ifndef FIXED_CLOCK_H
>>> +#define FIXED_CLOCK_H
>>> +
>>> +#define TYPE_FIXED_CLOCK "fixed-clock"
>>> +#define FIXED_CLOCK(obj) OBJECT_CHECK(FixedClock, (obj),
>>> TYPE_FIXED_CLOCK)
>>> +
>>> +#endif /* FIXED_CLOCK_H */
>>> --
>>> 2.5.5
>>>
>>>
>
>
diff mbox

Patch

diff --git a/hw/misc/Makefile.objs b/hw/misc/Makefile.objs
index e504463..e8b8855 100644
--- a/hw/misc/Makefile.objs
+++ b/hw/misc/Makefile.objs
@@ -52,3 +52,5 @@  obj-$(CONFIG_MIPS_ITU) += mips_itu.o
 obj-$(CONFIG_PVPANIC) += pvpanic.o
 obj-$(CONFIG_EDU) += edu.o
 obj-$(CONFIG_HYPERV_TESTDEV) += hyperv_testdev.o
+
+obj-y += fixed-clock.o
diff --git a/hw/misc/fixed-clock.c b/hw/misc/fixed-clock.c
new file mode 100644
index 0000000..c273a91
--- /dev/null
+++ b/hw/misc/fixed-clock.c
@@ -0,0 +1,87 @@ 
+/*
+ * Fixed clock
+ *
+ *  Copyright (C) 2016 : GreenSocs Ltd
+ *      http://www.greensocs.com/ , email: info@greensocs.com
+ *
+ *  Frederic Konrad   <fred.konrad@greensocs.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include "qemu/osdep.h"
+#include "hw/qdev.h"
+#include "hw/misc/fixed-clock.h"
+#include "qemu/qemu-clock.h"
+#include "qapi/error.h"
+
+/* #define DEBUG_FIXED_CLOCK */
+
+#ifdef DEBUG_FIXED_CLOCK
+#define DPRINTF(fmt, ...) \
+do { printf("fixed-clock: " fmt , ## __VA_ARGS__); } while (0)
+#else
+#define DPRINTF(fmt, ...) do { } while (0)
+#endif
+
+typedef struct {
+    DeviceState parent_obj;
+
+    uint32_t rate;
+    struct qemu_clk out;
+} FixedClock;
+
+static Property fixed_clock_properties[] = {
+    DEFINE_PROP_UINT32("rate", FixedClock, rate, 0),
+    DEFINE_PROP_END_OF_LIST()
+};
+
+static void fixed_clock_realizefn(DeviceState *d, Error **errp)
+{
+    FixedClock *s = FIXED_CLOCK(d);
+
+    qemu_clk_update_rate(&s->out, s->rate);
+}
+
+static void fixed_clock_instance_init(Object *obj)
+{
+    FixedClock *s = FIXED_CLOCK(obj);
+
+    object_initialize(&s->out, sizeof(s->out), TYPE_CLOCK);
+    qemu_clk_attach_to_device(DEVICE(obj), &s->out, "clk_out");
+}
+
+static void fixed_clock_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->realize = fixed_clock_realizefn;
+    dc->props = fixed_clock_properties;
+}
+
+static const TypeInfo fixed_clock_info = {
+    .name          = TYPE_FIXED_CLOCK,
+    .parent        = TYPE_DEVICE,
+    .instance_size = sizeof(FixedClock),
+    .instance_init = fixed_clock_instance_init,
+    .class_init    = fixed_clock_class_init,
+};
+
+static void fixed_clock_register_types(void)
+{
+    type_register_static(&fixed_clock_info);
+}
+
+type_init(fixed_clock_register_types);
diff --git a/include/hw/misc/fixed-clock.h b/include/hw/misc/fixed-clock.h
new file mode 100644
index 0000000..1376444
--- /dev/null
+++ b/include/hw/misc/fixed-clock.h
@@ -0,0 +1,30 @@ 
+/*
+ * Fixed clock
+ *
+ *  Copyright (C) 2016 : GreenSocs Ltd
+ *      http://www.greensocs.com/ , email: info@greensocs.com
+ *
+ *  Frederic Konrad   <fred.konrad@greensocs.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef FIXED_CLOCK_H
+#define FIXED_CLOCK_H
+
+#define TYPE_FIXED_CLOCK "fixed-clock"
+#define FIXED_CLOCK(obj) OBJECT_CHECK(FixedClock, (obj), TYPE_FIXED_CLOCK)
+
+#endif /* FIXED_CLOCK_H */