Re: [PATCH v7 04/13] coresight-tpda: Add DSB dataset support

From: Suzuki K Poulose
Date: Mon Aug 07 2023 - 05:13:06 EST


On 04/08/2023 16:02, Suzuki K Poulose wrote:
On 25/07/2023 08:15, Tao Zhang wrote:
Read the DSB element size from the device tree. Set the register
bit that controls the DSB element size of the corresponding port.

Signed-off-by: Tao Zhang <quic_taozha@xxxxxxxxxxx>
---
  drivers/hwtracing/coresight/coresight-tpda.c | 96 +++++++++++++++++++++++++---
  drivers/hwtracing/coresight/coresight-tpda.h |  4 ++
  2 files changed, 90 insertions(+), 10 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-tpda.c b/drivers/hwtracing/coresight/coresight-tpda.c
index 8d2b9d2..7c71342 100644
--- a/drivers/hwtracing/coresight/coresight-tpda.c
+++ b/drivers/hwtracing/coresight/coresight-tpda.c
@@ -21,6 +21,58 @@
  DEFINE_CORESIGHT_DEVLIST(tpda_devs, "tpda");
+/* Search and read element data size from the TPDM node in

minor nit:

/*
 * Search ...

+ * the devicetree. Each input port of TPDA is connected to
+ * a TPDM. Different TPDM supports different types of dataset,
+ * and some may support more than one type of dataset.
+ * Parameter "inport" is used to pass in the input port number
+ * of TPDA, and it is set to 0 in the recursize call.

+ * Parameter "parent" is used to pass in the original call.

Please remove references to the past and describe "match_inport"

+ */
+static int tpda_set_element_size(struct tpda_drvdata *drvdata,
+               struct coresight_device *csdev, int inport, bool match_inport)

May be we could switch the order of the parameters:

match_inport, int port

Or even inport < 0, implies, port wont be matched.

i.e.,

tpda_set_element_size(drvdata, child, inport)

+{
+    static int nr_inport;
+    int i;
+    static bool tpdm_found;
+    struct coresight_device *in_csdev;
+
+    if (inport > (TPDA_MAX_INPORTS - 1))
+        return -EINVAL;
+
+    if (match_inport) {
+        nr_inport = inport;
+        tpdm_found = false;
+    }

Could we not avoid the static variables and this dance by making the function return the dsb_size ? See further down.


+
+    for (i = 0; i < csdev->pdata->nr_inconns; i++) {
+        in_csdev = csdev->pdata->in_conns[i]->src_dev;
+        if (!in_csdev)
+            break;
        continue ?
+
+        if (match_inport)
+            if (csdev->pdata->in_conns[i]->dest_port != inport)
+                continue;
+
+        if ((in_csdev->type == CORESIGHT_DEV_TYPE_SOURCE) &&
+                (in_csdev->subtype.source_subtype
+                == CORESIGHT_DEV_SUBTYPE_SOURCE_TPDM)) {

Please provide a helper :

static bool coresight_device_is_tpdm(csdev) {
    return
     (csdev->type == CORESIGHT_DEV_TYPE_SOURCE) &&
     (in_csdev->subtype.source_subtype ==
        CORESIGHT_DEV_SUBTYPE_SOURCE_TPDM);
}



+            of_property_read_u8(in_csdev->dev.parent->of_node,
+                    "qcom,dsb-element-size", &drvdata->dsb_esize[nr_inport]);



+            if (!tpdm_found)
+                tpdm_found = true;
+            else
+                dev_warn(drvdata->dev,
+                    "More than one TPDM is mapped to the TPDA input port %d.\n",
+                    nr_inport);
+            continue;
+        }
+        tpda_set_element_size(drvdata, in_csdev, 0, false);
+    }
+

/*
 * Read the DSB element size from the TPDM device
 * Returns
 *    the size read from the firmware if available.
 *    0 - Otherwise, with a Warning once.
 */
static int tpdm_read_dsb_element_size(struct coresight_device *csdev)
{
    int rc, size = 0;

    rc = fwnode_property_read_u8(dev_fwnode(csdev->dev.parent),
                     "qcom,dsb-element-size", &size);
    if (rc)
        dev_warn_once(&in->dev, "Failed to read TPDM DSB Element size: %d\n",
        rc);
    return size;
}

static int tpda_get_element_size(struct coresight_device *csdev,
                 int inport)
{
    int dsb_size = -ENOENT;

    for (i = 0; i < csdev->pdata->nr_inconns; i++) {
        in = csdev->pdata->in_conns[i]->src_dev;
        if (!in)
            continue;
        if (coresight_device_is_tpdm(in)) {
            /* Ignore the TPDMs that do not match port */
            if (inport > 0 &&
                (csdev->pdata->in_conns[i]->dest_port !=
                inport))
                continue;
            size = tpdm_read_dsb_element_size(csdev);
        } else {
            /* Recurse down the path */
            size = tpda_set_element_size(in, -1);
        }

        if (size < 0)
            return size;
        /* We have found a size, save it. */
        if (dsb_size < 0) {
            dsb_size = size;
        } else {
            /* We have duplicate TPDMs */
            return -EEXIST;
        }
    }
    return dsb_size;
}




+    return 0;
+}
+
  /* Settings pre enabling port control register */
  static void tpda_enable_pre_port(struct tpda_drvdata *drvdata)
  {
@@ -32,26 +84,43 @@ static void tpda_enable_pre_port(struct tpda_drvdata *drvdata)
      writel_relaxed(val, drvdata->base + TPDA_CR);
  }
-static void tpda_enable_port(struct tpda_drvdata *drvdata, int port)
+static int tpda_enable_port(struct tpda_drvdata *drvdata, int port)
  {
      u32 val;
      val = readl_relaxed(drvdata->base + TPDA_Pn_CR(port));
+    /*
+     * Configure aggregator port n DSB data set element size
+     * Set the bit to 0 if the size is 32
+     * Set the bit to 1 if the size is 64
+     */
+    if (drvdata->dsb_esize[port] == 32)
+        val &= ~TPDA_Pn_CR_DSBSIZE;
+    else if (drvdata->dsb_esize[port] == 64)
+        val |= TPDA_Pn_CR_DSBSIZE;

Couldn't this be detected via tpda_get_element_size()? see below.

+    else
+        return -EINVAL;
+
      /* Enable the port */
      val |= TPDA_Pn_CR_ENA;
      writel_relaxed(val, drvdata->base + TPDA_Pn_CR(port));
+
+    return 0;
  }
-static void __tpda_enable(struct tpda_drvdata *drvdata, int port)
+static int __tpda_enable(struct tpda_drvdata *drvdata, int port)
  {
+    int ret;
+
      CS_UNLOCK(drvdata->base);
      if (!drvdata->csdev->enable)
          tpda_enable_pre_port(drvdata);
-    tpda_enable_port(drvdata, port);
-
+    ret = tpda_enable_port(drvdata, port);
      CS_LOCK(drvdata->base);
+
+    return ret;
  }
  static int tpda_enable(struct coresight_device *csdev,
@@ -59,16 +128,23 @@ static int tpda_enable(struct coresight_device *csdev,
                 struct coresight_connection *out)
  {
      struct tpda_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+    int ret;
+
+    ret = tpda_set_element_size(drvdata, csdev, in->dest_port, true);

    size  = tpda_get_element_size(csdev, in->dest_port);
    switch (size) {
    case 32:
    case 64:
        break;

We also need :

case 0:
return -ENOENT;

Suzuki


    case -EEXIST:
        dev_warn_once("Detected multiple TPDMs on port %d", ..)
        fallthrough;
    default:
        return size;
    }

    drvdata->dsb_esize[in->dest_port] = size;

Suzuki



+    if (ret)
+        return ret;
      spin_lock(&drvdata->spinlock);
-    if (atomic_read(&in->dest_refcnt) == 0)
-        __tpda_enable(drvdata, in->dest_port);
+    if (atomic_read(&in->dest_refcnt) == 0) {
+        ret = __tpda_enable(drvdata, in->dest_port);
+        if (!ret) {
+            atomic_inc(&in->dest_refcnt);
+            dev_dbg(drvdata->dev, "TPDA inport %d enabled.\n", in->dest_port);
+        }
+    }
-    atomic_inc(&in->dest_refcnt);
      spin_unlock(&drvdata->spinlock);
-
-    dev_dbg(drvdata->dev, "TPDA inport %d enabled.\n", in->dest_port);
-    return 0;
+    return ret;
  }
  static void __tpda_disable(struct tpda_drvdata *drvdata, int port)
diff --git a/drivers/hwtracing/coresight/coresight-tpda.h b/drivers/hwtracing/coresight/coresight-tpda.h
index 0399678..12a1472 100644
--- a/drivers/hwtracing/coresight/coresight-tpda.h
+++ b/drivers/hwtracing/coresight/coresight-tpda.h
@@ -10,6 +10,8 @@
  #define TPDA_Pn_CR(n)        (0x004 + (n * 4))
  /* Aggregator port enable bit */
  #define TPDA_Pn_CR_ENA        BIT(0)
+/* Aggregator port DSB data set element size bit */
+#define TPDA_Pn_CR_DSBSIZE        BIT(8)
  #define TPDA_MAX_INPORTS    32
@@ -23,6 +25,7 @@
   * @csdev:      component vitals needed by the framework.
   * @spinlock:   lock for the drvdata value.
   * @enable:     enable status of the component.
+ * @dsb_esize:  DSB element size for each inport, it must be 32 or 64.
   */
  struct tpda_drvdata {
      void __iomem        *base;
@@ -30,6 +33,7 @@ struct tpda_drvdata {
      struct coresight_device    *csdev;
      spinlock_t        spinlock;
      u8            atid;
+    u8            dsb_esize[TPDA_MAX_INPORTS];
  };
  #endif  /* _CORESIGHT_CORESIGHT_TPDA_H */