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Wed, 10 Feb 2021 12:55:44 -0800 (PST) MIME-Version: 1.0 References: <20210209132040.5091-1-peter.maydell@linaro.org> <20210209132040.5091-3-peter.maydell@linaro.org> In-Reply-To: <20210209132040.5091-3-peter.maydell@linaro.org> From: Hao Wu Date: Wed, 10 Feb 2021 12:55:32 -0800 Message-ID: Subject: Re: [PATCH v2 2/4] clock: Add ClockPreUpdate callback event type To: Peter Maydell Cc: qemu-arm , QEMU Developers , Tyrone Ting , Luc Michel , =?UTF-8?Q?Philippe_Mathieu=2DDaud=C3=A9?= , Havard Skinnemoen Content-Type: multipart/alternative; boundary="000000000000727b1a05bb01a0db" Received-SPF: pass client-ip=2a00:1450:4864:20::22c; envelope-from=wuhaotsh@google.com; helo=mail-lj1-x22c.google.com X-Spam_score_int: -175 X-Spam_score: -17.6 X-Spam_bar: ----------------- X-Spam_report: (-17.6 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_MED=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, ENV_AND_HDR_SPF_MATCH=-0.5, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, USER_IN_DEF_DKIM_WL=-7.5, USER_IN_DEF_SPF_WL=-7.5 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" --000000000000727b1a05bb01a0db Content-Type: text/plain; charset="UTF-8" On Tue, Feb 9, 2021 at 5:21 AM Peter Maydell wrote: > Add a new callback event type ClockPreUpdate, which is called on > period changes before the period is updated. > > Signed-off-by: Peter Maydell > Reviewed-by: Hao Wu > --- > docs/devel/clocks.rst | 9 ++++++++- > include/hw/clock.h | 1 + > hw/core/clock.c | 3 +++ > 3 files changed, 12 insertions(+), 1 deletion(-) > > diff --git a/docs/devel/clocks.rst b/docs/devel/clocks.rst > index cd344e3fe5d..f0391e76b4f 100644 > --- a/docs/devel/clocks.rst > +++ b/docs/devel/clocks.rst > @@ -181,7 +181,14 @@ events. > > The events currently supported are: > > - * ``ClockUpdate`` : called after the input clock's period has changed > + * ``ClockPreUpdate`` : called when the input clock's period is about to > + update. This is useful if the device needs to do some action for > + which it needs to know the old value of the clock period. During > + this callback, Clock API functions like ``clock_get()`` or > + ``clock_ticks_to_ns()`` will use the old period. > + * ``ClockUpdate`` : called after the input clock's period has changed. > + During this callback, Clock API functions like ``clock_ticks_to_ns()`` > + will use the new period. > > Note that a clock only has one callback: it is not possible to register > different functions for different events. You must register a single > diff --git a/include/hw/clock.h b/include/hw/clock.h > index 5c73b4e7ae9..d7a6673c29e 100644 > --- a/include/hw/clock.h > +++ b/include/hw/clock.h > @@ -30,6 +30,7 @@ OBJECT_DECLARE_SIMPLE_TYPE(Clock, CLOCK) > */ > typedef enum ClockEvent { > ClockUpdate = 1, /* Clock period has just updated */ > + ClockPreUpdate = 2, /* Clock period is about to update */ > } ClockEvent; > > typedef void ClockCallback(void *opaque, ClockEvent event); > diff --git a/hw/core/clock.c b/hw/core/clock.c > index 71dc1f4de65..2c86091d8a3 100644 > --- a/hw/core/clock.c > +++ b/hw/core/clock.c > @@ -80,6 +80,9 @@ static void clock_propagate_period(Clock *clk, bool > call_callbacks) > > QLIST_FOREACH(child, &clk->children, sibling) { > if (child->period != clk->period) { > + if (call_callbacks) { > + clock_call_callback(child, ClockPreUpdate); > + } > child->period = clk->period; > trace_clock_update(CLOCK_PATH(child), CLOCK_PATH(clk), > CLOCK_PERIOD_TO_HZ(clk->period), > -- > 2.20.1 > > > --000000000000727b1a05bb01a0db Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable


=
On Tue, Feb 9, 2021 at 5:21 AM Peter = Maydell <peter.maydell@linar= o.org> wrote:
Add a new callback event type ClockPreUpdate, which is called on
period changes before the period is updated.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
R= eviewed-by: Hao Wu <wuhaotsh@goog= le.com>=C2=A0
---
=C2=A0docs/devel/clocks.rst | 9 ++++++++-
=C2=A0include/hw/clock.h=C2=A0 =C2=A0 | 1 +
=C2=A0hw/core/clock.c=C2=A0 =C2=A0 =C2=A0 =C2=A0| 3 +++
=C2=A03 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/docs/devel/clocks.rst b/docs/devel/clocks.rst
index cd344e3fe5d..f0391e76b4f 100644
--- a/docs/devel/clocks.rst
+++ b/docs/devel/clocks.rst
@@ -181,7 +181,14 @@ events.

=C2=A0The events currently supported are:

- * ``ClockUpdate`` : called after the input clock's period has changed=
+ * ``ClockPreUpdate`` : called when the input clock's period is about = to
+=C2=A0 =C2=A0update. This is useful if the device needs to do some action = for
+=C2=A0 =C2=A0which it needs to know the old value of the clock period. Dur= ing
+=C2=A0 =C2=A0this callback, Clock API functions like ``clock_get()`` or +=C2=A0 =C2=A0``clock_ticks_to_ns()`` will use the old period.
+ * ``ClockUpdate`` : called after the input clock's period has changed= .
+=C2=A0 =C2=A0During this callback, Clock API functions like ``clock_ticks_= to_ns()``
+=C2=A0 =C2=A0will use the new period.

=C2=A0Note that a clock only has one callback: it is not possible to regist= er
=C2=A0different functions for different events. You must register a single<= br> diff --git a/include/hw/clock.h b/include/hw/clock.h
index 5c73b4e7ae9..d7a6673c29e 100644
--- a/include/hw/clock.h
+++ b/include/hw/clock.h
@@ -30,6 +30,7 @@ OBJECT_DECLARE_SIMPLE_TYPE(Clock, CLOCK)
=C2=A0 */
=C2=A0typedef enum ClockEvent {
=C2=A0 =C2=A0 =C2=A0ClockUpdate =3D 1, /* Clock period has just updated */<= br> +=C2=A0 =C2=A0 ClockPreUpdate =3D 2, /* Clock period is about to update */<= br> =C2=A0} ClockEvent;

=C2=A0typedef void ClockCallback(void *opaque, ClockEvent event);
diff --git a/hw/core/clock.c b/hw/core/clock.c
index 71dc1f4de65..2c86091d8a3 100644
--- a/hw/core/clock.c
+++ b/hw/core/clock.c
@@ -80,6 +80,9 @@ static void clock_propagate_period(Clock *clk, bool call_= callbacks)

=C2=A0 =C2=A0 =C2=A0QLIST_FOREACH(child, &clk->children, sibling) {<= br> =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0if (child->period !=3D clk->period)= {
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 if (call_callbacks) {
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 clock_call_callbac= k(child, ClockPreUpdate);
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 }
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0child->period =3D clk-&g= t;period;
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0trace_clock_update(CLOCK_PA= TH(child), CLOCK_PATH(clk),
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 CLOCK_PERIOD_TO_HZ(clk->period),<= br> --
2.20.1


--000000000000727b1a05bb01a0db--