[PATCH 2/2] ARM: dts: at91: sama5d2: add ETM, ETB and ETMCK node

[Olivier Schonken]

Hi Alexandre

Resending this mail, the previous one was accidentally in html format,
thus rejected from the list.  My apologies.

I did try a couple of options regarding the clock, mck included, but
it would then hang when probing occurs in drivers/amba/bus.c when the
clock gets disabled. The dummy clock solved this issue, but I'm open
to better suggestions.

Regards
Olivier

On 01 Jul 2016 20:32, "Alexandre Belloni"
<alexandre.belloni at free-electrons.com> wrote:
>
> On 01/07/2016 at 16:37:11 +0200, Olivier Schonken wrote :
> > Add node to support SAMA5D2 Embedded Trace Macrocell and Embedded
> > Trace Buffer. Add a dummy clock node needed by drivers/amba/bus.c
> > for succesfull probe. The coresight clock is always present, and
> > can thus not be enabled/disabled by a register write.
> >
> > This patch depends on coresight-etm3x: Add ARM ETM-A5 peripheral ID
> > for proper functionality.
> >
> > Signed-off-by: Olivier Schonken <olivier.schonken at gmail.com>
> > ---
> >  arch/arm/boot/dts/sama5d2.dtsi | 44 ++++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 44 insertions(+)
> >
> > diff --git a/arch/arm/boot/dts/sama5d2.dtsi b/arch/arm/boot/dts/sama5d2.dtsi
> > index 5d63206..4a3a3fb 100644
> > --- a/arch/arm/boot/dts/sama5d2.dtsi
> > +++ b/arch/arm/boot/dts/sama5d2.dtsi
> > @@ -77,6 +77,37 @@
> >               interrupts = <2 IRQ_TYPE_LEVEL_HIGH 0>;
> >       };
> >
> > +     etb: etb at 00740000 {
> > +             compatible = "arm,coresight-etb10", "arm,primecell";
> > +             reg = <0x740000 0x1000>;
> > +             status = "okay";
> > +
> > +             clocks = <&etmck>;
> > +             clock-names = "apb_pclk";
> > +
> > +             port {
> > +                     etb_in: endpoint {
> > +                             slave-mode;
> > +                             remote-endpoint = <&etm_out>;
> > +                     };
> > +             };
> > +     };
> > +
> > +     etm: etm at 0073C000 {
> > +             compatible = "arm,coresight-etm3x", "arm,primecell";
> > +             reg = <0x73C000 0x1000>;
> > +             status = "okay";
> > +
> > +             clocks = <&etmck>;
> > +             clock-names = "apb_pclk";
> > +
> > +             port {
> > +                     etm_out: endpoint {
> > +                             remote-endpoint = <&etb_in>;
> > +                     };
> > +             };
> > +     };
> > +
> >       memory {
> >               reg = <0x20000000 0x20000000>;
> >       };
> > @@ -474,6 +505,19 @@
> >                                       };
> >                               };
> >
> > +                             /*
> > +                              * This is a dummy clock needed by
> > +                              * drivers/amba/bus.c when probing
> > +                              * for ETM/ETB. On SAMA5D2 the coresight
> > +                              * clock is always supplied.
> > +                             */
> > +
> > +                             etmck: etmck {
> > +                                     #clock-cells = <0>;
> > +                                     compatible = "fixed-clock";
> > +                                     clock-frequency = <0>;
> > +                             };
> > +
>
> Hum, maybe you could take mck instead of adding a dummy clock in the
> PCM.
>
> Boris, do you have a better idea?
>
> --
> Alexandre Belloni, Free Electrons
> Embedded Linux and Kernel engineering
> http://free-electrons.com