Re: [PATCH v5 05/10] coresight-tpda: Add support to configure CMB element

[Tao Zhang]

On 1/31/2024 6:02 PM, Suzuki K Poulose wrote:
> On 31/01/2024 01:39, Tao Zhang wrote:
> > On 1/30/2024 8:35 PM, Suzuki K Poulose wrote:
> > > On 30/01/2024 09:02, Tao Zhang wrote:
> > > > Read the CMB element size from the device tree. Set the register
> > > > bit that controls the CMB element size of the corresponding port.
> > > >
> > > > Reviewed-by: James Clark <james.clark@xxxxxxx>
> > > > Signed-off-by: Tao Zhang <quic_taozha@xxxxxxxxxxx>
> > > > Signed-off-by: Mao Jinlong <quic_jinlmao@xxxxxxxxxxx>
> > > > ---
> > > >   drivers/hwtracing/coresight/coresight-tpda.c | 123 
> > > > +++++++++++--------
> > > >   drivers/hwtracing/coresight/coresight-tpda.h |   6 +
> > > >   2 files changed, 79 insertions(+), 50 deletions(-)
> > > >
> > > > diff --git a/drivers/hwtracing/coresight/coresight-tpda.c 
> > > > b/drivers/hwtracing/coresight/coresight-tpda.c
> > > > index 4ac954f4bc13..fcddff3ded81 100644
> > > > --- a/drivers/hwtracing/coresight/coresight-tpda.c
> > > > +++ b/drivers/hwtracing/coresight/coresight-tpda.c
> > > > @@ -18,6 +18,7 @@
> > > >   #include "coresight-priv.h"
> > > >   #include "coresight-tpda.h"
> > > >   #include "coresight-trace-id.h"
> > > > +#include "coresight-tpdm.h"
> > > >     DEFINE_CORESIGHT_DEVLIST(tpda_devs, "tpda");
> > > >   @@ -28,24 +29,57 @@ static bool coresight_device_is_tpdm(struct 
> > > > coresight_device *csdev)
> > > >               CORESIGHT_DEV_SUBTYPE_SOURCE_TPDM);
> > > >   }
> > > >   +static void tpdm_clear_element_size(struct coresight_device *csdev)
> > > > +{
> > > > +    struct tpda_drvdata *drvdata = 
> > > > dev_get_drvdata(csdev->dev.parent);
> > > > +
> > > > +    drvdata->dsb_esize = 0;
> > > > +    drvdata->cmb_esize = 0;
> > > > +}
> > > > +
> > > > +static void tpda_set_element_size(struct tpda_drvdata *drvdata, 
> > > > u32 *val)
> > > > +{
> > > > +
> > >
> > >
> > >
> > > > +    if (drvdata->dsb_esize == 64)
> > > > +        *val |= TPDA_Pn_CR_DSBSIZE;
> > >
> > > We don't seem to be clearing the fields we modify, before updating 
> > > them. This may be OK in real world where the device connected to 
> > > TPDA port
> > > may not change. But it is always safer to clear the bits and set it.
> > >
> > > e.g.:
> > >     *val &= ~(TPDA_Pn_CR_DSBSIZE | TPDA_Pn_CR_CMBSIZE);
> > >
> > >
> > >
> > > > +    else if (drvdata->dsb_esize == 32)
> > > > +        *val &= ~TPDA_Pn_CR_DSBSIZE;
> > > > +
> > > > +    if (drvdata->cmb_esize == 64)
> > > > +        *val |= FIELD_PREP(TPDA_Pn_CR_CMBSIZE, 0x2);
> > > > +    else if (drvdata->cmb_esize == 32)
> > > > +        *val |= FIELD_PREP(TPDA_Pn_CR_CMBSIZE, 0x1);
> > >
> > > Similarly here ^^^. I am happy to fix it up if you are OK with it 
> > > (unless there are other changes that need a respin)
> >
> > Thank you. I would be very grateful if you could help for this.
>
> Given, you need to respin, please incorporate this change too.

Sure.

Is it OK if I modify the code as follow and update to this patch directly?

    *val &= ~(TPDA_Pn_CR_DSBSIZE | TPDA_Pn_CR_CMBSIZE);

    if (drvdata->dsb_esize == 64)
        *val |= TPDA_Pn_CR_DSBSIZE;
    else if (drvdata->dsb_esize == 32)
        *val &= ~TPDA_Pn_CR_DSBSIZE;

    if (drvdata->cmb_esize == 64)
        *val |= FIELD_PREP(TPDA_Pn_CR_CMBSIZE, 0x2);
    else if (drvdata->cmb_esize == 32)
        *val |= FIELD_PREP(TPDA_Pn_CR_CMBSIZE, 0x1);
    else if (drvdata->cmb_esize == 8)
        *val &= ~TPDA_Pn_CR_CMBSIZE;

Best,

Tao

> Suzuki