Re: [PATCH v4 03/11] coresight-tpdm: Initialize DSB subunit configuration

From: Tao Zhang
Date: Thu May 25 2023 - 04:13:39 EST



On 5/23/2023 9:42 PM, Suzuki K Poulose wrote:
On 27/04/2023 10:00, 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 | 60 +++++++++++++++++++++++++---
  drivers/hwtracing/coresight/coresight-tpdm.h | 17 ++++++++
  2 files changed, 72 insertions(+), 5 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-tpdm.c b/drivers/hwtracing/coresight/coresight-tpdm.c
index ba1867f..6f8a8ab 100644
--- a/drivers/hwtracing/coresight/coresight-tpdm.c
+++ b/drivers/hwtracing/coresight/coresight-tpdm.c
@@ -20,17 +20,51 @@
    DEFINE_CORESIGHT_DEVLIST(tpdm_devs, "tpdm");
  +static void tpdm_reset_datasets(struct tpdm_drvdata *drvdata)
+{
+    if (drvdata->datasets & TPDM_PIDR0_DS_DSB) {
+        memset(drvdata->dsb, 0, sizeof(struct dsb_dataset));
+
+        drvdata->dsb->trig_ts = true;
+        drvdata->dsb->trig_type = false;
+    }
+}
+
+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;
+}
+

Given this is not reused, we could simply inline it in the caller
to avoid creating a confusion, like other operations ?
Sure, I will update it in the next patch series.

  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

minor nit: Please could you extend the existing comment than adding a
new multi-line comment ?
Sure, I will update it in the next patch series.

+ * 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 +144,24 @@ static const struct coresight_ops tpdm_cs_ops = {
      .source_ops    = &tpdm_source_ops,
  };
  -static void tpdm_init_default_data(struct tpdm_drvdata *drvdata)
+static int tpdm_datasets_setup(struct tpdm_drvdata *drvdata)
  {
      u32 pidr;
  -    CS_UNLOCK(drvdata->base);
      /*  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);

Why are we removing the CS_{UN,}LOCK here ?

CS_UNLOCK is used before writing data to Coresight registers. Here this function

doesn't need to write data to any registers, so I remove the CS_{UN,}LOCK here.


Best,

Tao


Rest looks OK to me.

Suzuki

+
+    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;
+        }
+    }
+
+    return 0;
  }
    /*
@@ -181,6 +224,7 @@ 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 +244,12 @@ static int tpdm_probe(struct amba_device *adev, const struct amba_id *id)
        drvdata->base = base;
  +    ret = tpdm_datasets_setup(drvdata);
+    if (ret)
+        return ret;
+
+    tpdm_reset_datasets(drvdata);
+
      /* Set up coresight component description */
      desc.name = coresight_alloc_device_name(&tpdm_devs, dev);
      if (!desc.name)
@@ -216,7 +266,7 @@ 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);
+
      /* 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 5438540..68f33bd 100644
--- a/drivers/hwtracing/coresight/coresight-tpdm.h
+++ b/drivers/hwtracing/coresight/coresight-tpdm.h
@@ -11,8 +11,14 @@
    /* DSB Subunit Registers */
  #define TPDM_DSB_CR        (0x780)
+#define TPDM_DSB_TIER        (0x784)
+
  /* Enable bit for DSB subunit */
  #define TPDM_DSB_CR_ENA        BIT(0)
+/* Enable bit for DSB subunit trigger type */
+#define TPDM_DSB_CR_TRIG_TYPE        BIT(12)
+/* Enable bit for DSB subunit trigger timestamp */
+#define TPDM_DSB_TIER_XTRIG_TSENAB        BIT(1)
    /* TPDM integration test registers */
  #define TPDM_ITATBCNTRL        (0xEF0)
@@ -41,6 +47,16 @@
  #define TPDM_PIDR0_DS_DSB    BIT(1)
    /**
+ * struct dsb_dataset - specifics associated to dsb dataset
+ * @trig_ts:          Enable/Disable trigger timestamp.
+ * @trig_type:        Enable/Disable trigger type.
+ */
+struct dsb_dataset {
+    bool            trig_ts;
+    bool            trig_type;
+};
+
+/**
   * struct tpdm_drvdata - specifics associated to an TPDM component
   * @base:       memory mapped base address for this component.
   * @dev:        The device entity associated to this component.
@@ -57,6 +73,7 @@ struct tpdm_drvdata {
      spinlock_t        spinlock;
      bool            enable;
      unsigned long        datasets;
+    struct dsb_dataset    *dsb;
  };
    #endif  /* _CORESIGHT_CORESIGHT_TPDM_H */

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