Re: [PATCH v2 4/8] coresight-tpdm: Add support to configure CMB

[Tao Zhang]

On 10/30/2023 7:29 PM, James Clark wrote:
> On 25/10/2023 03:53, Tao Zhang wrote:
> > TPDM CMB subunits support two forms of CMB data set element creation:
> > continuous and trace-on-change collection mode. Continuous change
> > creates CMB data set elements on every CMBCLK edge. Trace-on-change
> > creates CMB data set elements only when a new data set element differs
> > in value from the previous element in a CMB data set. Set CMB_CR.MODE
> > to 0 for continuous CMB collection mode. Set CMB_CR.MODE to 1 for
> > trace-on-change CMB collection mode
> >
> > Signed-off-by: Tao Zhang <quic_taozha@xxxxxxxxxxx>
> > Signed-off-by: Jinlong Mao <quic_jinlmao@xxxxxxxxxxx>
> > ---
> >   .../ABI/testing/sysfs-bus-coresight-devices-tpdm   | 10 +++
> >   drivers/hwtracing/coresight/coresight-tpdm.c       | 71 ++++++++++++++++++++++
> >   drivers/hwtracing/coresight/coresight-tpdm.h       | 12 ++++
> >   3 files changed, 93 insertions(+)
> >
> > diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
> > index f07218e..ace7231 100644
> > --- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
> > +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
> > @@ -170,3 +170,13 @@ Contact:	Jinlong Mao (QUIC) <quic_jinlmao@xxxxxxxxxxx>, Tao Zhang (QUIC) <quic_t
> >   Description:
> >   		(RW) Set/Get the MSR(mux select register) for the DSB subunit
> >   		TPDM.
> > +
> > +What:		/sys/bus/coresight/devices/<tpdm-name>/cmb_mode
> > +Date:		March 2023
> > +KernelVersion	6.7
> > +Contact:	Jinlong Mao (QUIC) <quic_jinlmao@xxxxxxxxxxx>, Tao Zhang (QUIC) <quic_taozha@xxxxxxxxxxx>
> > +Description:	(Write) Set the data collection mode of CMB tpdm.
> I know it's expanded elsewhere, but it's probably worth expanding the
> CMB abbreviation here as well so people reading the docs don't have to
> go into the code.

Sure, I will update in the next patch series.


Best,

Tao

> Otherwise:
>
> Reviewed-by: James Clark <james.clark@xxxxxxx>
>
> > +
> > +		Accepts only one of the 2 values -  0 or 1.
> > +		0 : Continuous CMB collection mode.
> > +		1 : Trace-on-change CMB collection mode.
> > diff --git a/drivers/hwtracing/coresight/coresight-tpdm.c b/drivers/hwtracing/coresight/coresight-tpdm.c
> > index c8bb388..efb376e 100644
> > --- a/drivers/hwtracing/coresight/coresight-tpdm.c
> > +++ b/drivers/hwtracing/coresight/coresight-tpdm.c
> > @@ -148,6 +148,18 @@ static umode_t tpdm_dsb_is_visible(struct kobject *kobj,
> >   	return 0;
> >   }
> [...]