Re: [PATCH v3 03/11] coresight-tpdm: Initialize DSB subunit configuration

[Tao Zhang]

Hi Suzuki,

On 3/23/2023 10:23 PM, Suzuki K Poulose wrote:
> On 23/03/2023 06:04, Tao Zhang wrote:
> > DSB is used for monitoring “events”. Events are something that
> > occurs at some point in time. It could be a state decode, the
> > act of writing/reading a particular address, a FIFO being empty,
> > etc. This decoding of the event desired is done outside TPDM.
> > DSB subunit need to be configured in enablement and disablement.
> > A struct that specifics associated to dsb dataset is needed. It
> > saves the configuration and parameters of the dsb datasets. This
> > change is to add this struct and initialize the configuration of
> > DSB subunit.
> >
> > Signed-off-by: Tao Zhang <quic_taozha@xxxxxxxxxxx>
> > ---
> >   drivers/hwtracing/coresight/coresight-tpdm.c | 58 
> > +++++++++++++++++++++++++---
> >   drivers/hwtracing/coresight/coresight-tpdm.h | 17 ++++++++
> >   2 files changed, 70 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/hwtracing/coresight/coresight-tpdm.c 
> > b/drivers/hwtracing/coresight/coresight-tpdm.c
> > index f4854af..5e1e2ba 100644
> > --- a/drivers/hwtracing/coresight/coresight-tpdm.c
> > +++ b/drivers/hwtracing/coresight/coresight-tpdm.c
> > @@ -20,17 +20,59 @@
> >     DEFINE_CORESIGHT_DEVLIST(tpdm_devs, "tpdm");
> >   +static int tpdm_init_datasets(struct tpdm_drvdata *drvdata)
>
>
> > +{
> > +    if (drvdata->datasets & TPDM_PIDR0_DS_DSB) {
> > +        if (!drvdata->dsb) {
> > +            drvdata->dsb = devm_kzalloc(drvdata->dev,
> > +                            sizeof(*drvdata->dsb), GFP_KERNEL);
> > +            if (!drvdata->dsb)
> > +                return -ENOMEM;
>
> Please do not club init/allocation of datasets to "resetting" the
> datasets. Why don't we move the allocation to tpmd_datasets_setup() ?
> And this function could simply be called :
>
> tpdm_reset_datasets()
>
> and can be called from the tpdm_datasets_setup() too.
I will update this in the next patch series.
> > +        } else
> > +            memset(drvdata->dsb, 0, sizeof(struct dsb_dataset));
> > +
> > +        drvdata->dsb->trig_ts = true;
> > +        drvdata->dsb->trig_type = false;
> > +    }
> > +
> > +    return 0;
> > +}
> > +
> > +static void set_trigger_type(struct tpdm_drvdata *drvdata, u32 *val)
> > +{
> > +    if (drvdata->dsb->trig_type)
> > +        *val |= TPDM_DSB_CR_TRIG_TYPE;
> > +    else
> > +        *val &= ~TPDM_DSB_CR_TRIG_TYPE;
> > +}
> > +
>
> Do we really need a function for this ? How is it different from 
> trig_ts ?

"trig_type" is for setting trigger type, and "trig_ts" is for setting 
trigger

timestamp. These two variables are configured in two different registers.

Do you mean we don't need to wrap it as a function here?

> >   static void tpdm_enable_dsb(struct tpdm_drvdata *drvdata)
> >   {
> >       u32 val;
> >   -    /* Set the enable bit of DSB control register to 1 */
> > +    val = readl_relaxed(drvdata->base + TPDM_DSB_TIER);
> > +    /* Set trigger timestamp */
> > +    if (drvdata->dsb->trig_ts)
> > +        val |= TPDM_DSB_TIER_XTRIG_TSENAB;
> > +    else
> > +        val &= ~TPDM_DSB_TIER_XTRIG_TSENAB;
> > +    writel_relaxed(val, drvdata->base + TPDM_DSB_TIER);
> > +
> >       val = readl_relaxed(drvdata->base + TPDM_DSB_CR);
> > +    /* Set trigger type */
> > +    set_trigger_type(drvdata, &val);
> > +    /* Set the enable bit of DSB control register to 1 */
> >       val |= TPDM_DSB_CR_ENA;
> >       writel_relaxed(val, drvdata->base + TPDM_DSB_CR);
> >   }
> >     /* TPDM enable operations */
> > +/* The TPDM or Monitor serves as data collection component for various
> > + * dataset types. It covers Basic Counts(BC), Tenure Counts(TC),
> > + * Continuous Multi-Bit(CMB), Multi-lane CMB(MCMB) and Discrete Single
> > + * Bit(DSB). This function will initialize the configuration according
> > + * to the dataset type supported by the TPDM.
> > + */
> >   static void __tpdm_enable(struct tpdm_drvdata *drvdata)
> >   {
> >       CS_UNLOCK(drvdata->base);
> > @@ -110,15 +152,13 @@ static const struct coresight_ops tpdm_cs_ops = {
> >       .source_ops    = &tpdm_source_ops,
> >   };
> >   -static void tpdm_init_default_data(struct tpdm_drvdata *drvdata)
> > +static void tpdm_datasets_setup(struct tpdm_drvdata *drvdata)
> >   {
> >       u32 pidr;
> >   -    CS_UNLOCK(drvdata->base);
>
> Why is this removed ?
We only need to read the register here, don't need to unlock the 
registers here, right?
> >       /*  Get the datasets present on the TPDM. */
> >       pidr = readl_relaxed(drvdata->base + CORESIGHT_PERIPHIDR0);
> >       drvdata->datasets |= pidr & GENMASK(TPDM_DATASETS - 1, 0);
> > -    CS_LOCK(drvdata->base);
> >   }
> >     /*
> > @@ -181,6 +221,7 @@ static int tpdm_probe(struct amba_device *adev, 
> > const struct amba_id *id)
> >       struct coresight_platform_data *pdata;
> >       struct tpdm_drvdata *drvdata;
> >       struct coresight_desc desc = { 0 };
> > +    int ret;
> >         pdata = coresight_get_platform_data(dev);
> >       if (IS_ERR(pdata))
> > @@ -200,6 +241,8 @@ static int tpdm_probe(struct amba_device *adev, 
> > const struct amba_id *id)
> >         drvdata->base = base;
> >   +    tpdm_datasets_setup(drvdata);
> > +
> >       /* Set up coresight component description */
> >       desc.name = coresight_alloc_device_name(&tpdm_devs, dev);
> >       if (!desc.name)
> > @@ -216,7 +259,12 @@ static int tpdm_probe(struct amba_device *adev, 
> > const struct amba_id *id)
> >           return PTR_ERR(drvdata->csdev);
> >         spin_lock_init(&drvdata->spinlock);
> > -    tpdm_init_default_data(drvdata);
> > +    ret = tpdm_init_datasets(drvdata);
>
> Couldn't this be done before the coresight_register() ? As such
> I don't see any dependency on having a csdev ?

I will update this in the next patch series.


Tao

> Suzuki