Re: [PATCH v5 04/10] coresight-tpdm: Add DSB dataset support

Hi,

On Tue, 12 Apr 2022 at 13:51, Mao Jinlong quic_jinlmao@quicinc.com wrote:

TPDM serves as data collection component for various dataset types. DSB(Discrete Single Bit) is one of the dataset types. DSB subunit can be enabled for data collection by writing 1 to the first bit of DSB_CR register. This change is to add enable/disable function for DSB dataset by writing DSB_CR register.

Signed-off-by: Tao Zhang quic_taozha@quicinc.com Signed-off-by: Mao Jinlong quic_jinlmao@quicinc.com

---

drivers/hwtracing/coresight/coresight-tpdm.c | 61 ++++++++++++++++++++ drivers/hwtracing/coresight/coresight-tpdm.h | 21 +++++++ 2 files changed, 82 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-tpdm.c b/drivers/hwtracing/coresight/coresight-tpdm.c index 3900ae50670a..d7b970cdcf51 100644 --- a/drivers/hwtracing/coresight/coresight-tpdm.c +++ b/drivers/hwtracing/coresight/coresight-tpdm.c @@ -20,7 +20,28 @@

DEFINE_CORESIGHT_DEVLIST(tpdm_devs, "tpdm");

+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_CR);
  

•   val = val | BIT(0);
  

Please use #defined values, declared in the header file rather than BIT(x) here. (the etm4x drivers have been recently updated to use the same pattern). e.g. val |= TPDM_DSB_CR_ENA;

•   writel_relaxed(val, drvdata->base + TPDM_DSB_CR);
  

+}

/* TPDM enable operations */ +static void _tpdm_enable(struct tpdm_drvdata *drvdata) +{

•   CS_UNLOCK(drvdata->base);
  

•   /* Check if DSB datasets is present for TPDM. */
  

•   if (test_bit(TPDM_DS_DSB, drvdata->datasets))
  

•           tpdm_enable_dsb(drvdata);
  

•   CS_LOCK(drvdata->base);
  

+}

static int tpdm_enable(struct coresight_device *csdev, struct perf_event *event, u32 mode) { @@ -32,6 +53,7 @@ static int tpdm_enable(struct coresight_device *csdev, return -EBUSY; }

•   _tpdm_enable(drvdata);
    drvdata->enable = true;
    mutex_unlock(&drvdata->lock);
  
  

@@ -39,7 +61,29 @@ static int tpdm_enable(struct coresight_device *csdev, return 0; }

+static void tpdm_disable_dsb(struct tpdm_drvdata *drvdata) +{

•   u32 val;
  

•   /* Set the enable bit of DSB control register to 0 */
  

•   val = readl_relaxed(drvdata->base + TPDM_DSB_CR);
  

•   val = val & ~BIT(0);
  

val &= ~TPDM_DSB_CR_ENA;

•   writel_relaxed(val, drvdata->base + TPDM_DSB_CR);
  

+}

/* TPDM disable operations */ +static void _tpdm_disable(struct tpdm_drvdata *drvdata) +{

•   CS_UNLOCK(drvdata->base);
  

•   /* Check if DSB datasets is present for TPDM. */
  

•   if (test_bit(TPDM_DS_DSB, drvdata->datasets))
  

•           tpdm_disable_dsb(drvdata);
  

•   CS_LOCK(drvdata->base);
  

+}

static void tpdm_disable(struct coresight_device *csdev, struct perf_event *event) { @@ -51,6 +95,7 @@ static void tpdm_disable(struct coresight_device *csdev, return; }

•   _tpdm_disable(drvdata);
    drvdata->enable = false;
    mutex_unlock(&drvdata->lock);
  
  

@@ -66,6 +111,21 @@ static const struct coresight_ops tpdm_cs_ops = { .source_ops = &tpdm_source_ops, };

+static void tpdm_init_default_data(struct tpdm_drvdata *drvdata) +{

•   int i;
  

•   u32 pidr;
  

•   CS_UNLOCK(drvdata->base);
  

•   /*  Get the datasets present on the TPDM. */
  

•   pidr = readl_relaxed(drvdata->base + CORESIGHT_PERIPHIDR0);
  

•   for (i = 0; i < TPDM_DATASETS; i++) {
  

•           if (pidr & BIT(i))
  

•                   __set_bit(i, drvdata->datasets);
  

Could this be considerably simpified? - there are a maximum of 7 bits for datasets - and you are setting the same bit in drvdata->datasets for each bit in pidr

e.g. if the datasets declaration is a simple unsigned long, then the following is easier to read and understand:

drvdata->datasets |= pidr & GENMASK(TPDM_DATASETS - 1, 0);

The tests above could then become: if (drvdata->datasets & BIT(TPDM_DS_DSB)) ...

•   }
  

•   CS_LOCK(drvdata->base);
  

+}

static int tpdm_probe(struct amba_device *adev, const struct amba_id *id) { struct device *dev = &adev->dev; @@ -104,6 +164,7 @@ static int tpdm_probe(struct amba_device *adev, const struct amba_id *id) if (IS_ERR(drvdata->csdev)) return PTR_ERR(drvdata->csdev);

•   tpdm_init_default_data(drvdata);
    /* Decrease pm refcount when probe is done.*/
    pm_runtime_put(&adev->dev);
  
  

diff --git a/drivers/hwtracing/coresight/coresight-tpdm.h b/drivers/hwtracing/coresight/coresight-tpdm.h index 94a7748a5426..8f05070879c4 100644 --- a/drivers/hwtracing/coresight/coresight-tpdm.h +++ b/drivers/hwtracing/coresight/coresight-tpdm.h @@ -6,6 +6,25 @@ #ifndef _CORESIGHT_CORESIGHT_TPDM_H #define _CORESIGHT_CORESIGHT_TPDM_H

+/* The max number of the datasets that TPDM supports */ +#define TPDM_DATASETS 7

+/* DSB Subunit Registers */ +#define TPDM_DSB_CR (0x780)

declare the enable bit here with comment documenting usage - see above.

+/**

• • This enum is for PERIPHIDR0 register of TPDM.
• • The fields [6:0] of PERIPHIDR0 are used to determine what
• • interfaces and subunits are present on a given TPDM.
• • PERIPHIDR0[0] : Fix to 1 if ImplDef subunit present, else 0
• • PERIPHIDR0[1] : Fix to 1 if DSB subunit present, else 0
• */

+enum tpdm_dataset {

•   TPDM_DS_IMPLDEF,
  

•   TPDM_DS_DSB,
  

+};

/**

• struct tpdm_drvdata - specifics associated to an TPDM component
• @base: memory mapped base address for this component.

@@ -13,6 +32,7 @@

• @csdev: component vitals needed by the framework.
• @lock: lock for the enable value.
• @enable: enable status of the component.

• • @datasets: The datasets types present of the TPDM.
  */

struct tpdm_drvdata { @@ -21,6 +41,7 @@ struct tpdm_drvdata { struct coresight_device *csdev; struct mutex lock; bool enable;

•   DECLARE_BITMAP(datasets, TPDM_DATASETS);
  

Could this simply be declared as an unsigned long? - then simplify the code in the .c file.

Regards

Mike

};

#endif /* _CORESIGHT_CORESIGHT_TPDM_H */

2.17.1