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

Suzuki K Poulose
2023-03-23T14:23:38Z

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@quicinc.com>
> ---
> 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.

> + } 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 ?

> 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 ?

> /* 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 ?

Suzuki