Re: [PATCH v3 07/11] coresight-tpdm: Add nodes for dsb edge control

From: Tao Zhang
Date: Mon Mar 27 2023 - 03:37:11 EST


Hi Suzuki,

On 3/24/2023 1:04 AM, Suzuki K Poulose wrote:
On 23/03/2023 06:04, Tao Zhang wrote:
Add the nodes to set value for DSB edge control and DSB edge
control mask. Each DSB subunit TPDM has maximum of n(n<16) EDCR
resgisters to configure edge control. DSB edge detection control
00: Rising edge detection
01: Falling edge detection
10: Rising and falling edge detection (toggle detection) > And each DSB subunit TPDM has maximum of m(m<8) ECDMR registers to
configure mask. Eight 32 bit registers providing DSB interface
edge detection mask control.

Signed-off-by: Tao Zhang <quic_taozha@xxxxxxxxxxx>
---
  .../ABI/testing/sysfs-bus-coresight-devices-tpdm   |  26 ++++
  drivers/hwtracing/coresight/coresight-tpdm.c       | 142 ++++++++++++++++++++-
  drivers/hwtracing/coresight/coresight-tpdm.h       |  14 ++
  3 files changed, 181 insertions(+), 1 deletion(-)

diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
index f13e282..094d624 100644
--- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
+++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
@@ -45,3 +45,29 @@ Description:
          tpdm.
            Accepts the value needs to be greater than 0.
+
+What: /sys/bus/coresight/devices/<tpdm-name>/dsb_edge_ctrl
+Date:        March 2023
+KernelVersion    6.3
+Contact:    Jinlong Mao (QUIC) <quic_jinlmao@xxxxxxxxxxx>, Tao Zhang (QUIC) <quic_taozha@xxxxxxxxxxx>
+Description:
+        (Write) Set the edge control of DSB tpdm. Read the
+        edge control of DSB tpdm.

Could we not say :
    Read / Write a set of the edge control registers of the DSB in
        TPDM
I will update this in the next patch series.
+
+        Accepts the following three values.

This is a bit confusing, at least to me. This could either mean,
a single write of values 1-3 are accepted.

Got it. The following three values are required.

+        value 1: Start EDCR register number
+        value 2: End EDCR register number
+        value 3: The value need to be written

But you really mean to say, the writes must be of the following format
    <integer1> <integer2> <integer3>

where :
        <integer1> : Start EDCR ...
        ....

I will update this in the next patch series.
+
+What: /sys/bus/coresight/devices/<tpdm-name>/dsb_edge_ctrl_mask
+Date:        March 2023
+KernelVersion    6.3
+Contact:    Jinlong Mao (QUIC) <quic_jinlmao@xxxxxxxxxxx>, Tao Zhang (QUIC) <quic_taozha@xxxxxxxxxxx>
+Description:
+        (Write) Set the edge control mask of DSB tpdm. Read
+        the edge control mask of DSB tpdm.
+
+        Accepts the following three values.
+        value 1: Start EDCMR register number
+        value 2: End EDCMR register number
+        value 3: The value need to be written

Similarly here.
I will update this in the next patch series.

diff --git a/drivers/hwtracing/coresight/coresight-tpdm.c b/drivers/hwtracing/coresight/coresight-tpdm.c
index 8cd822f..2a0b36c 100644
--- a/drivers/hwtracing/coresight/coresight-tpdm.c
+++ b/drivers/hwtracing/coresight/coresight-tpdm.c
@@ -88,7 +88,14 @@ static void set_trigger_type(struct tpdm_drvdata *drvdata, u32 *val)
    static void tpdm_enable_dsb(struct tpdm_drvdata *drvdata)
  {
-    u32 val;
+    u32 val, i;
+
+    for (i = 0; i < TPDM_DSB_MAX_EDCR; i++)
+        writel_relaxed(drvdata->dsb->edge_ctrl[i],
+               drvdata->base + TPDM_DSB_EDCR(i));
+    for (i = 0; i < TPDM_DSB_MAX_EDCMR; i++)
+        writel_relaxed(drvdata->dsb->edge_ctrl_mask[i],
+               drvdata->base + TPDM_DSB_EDCMR(i));
        val = readl_relaxed(drvdata->base + TPDM_DSB_TIER);
      /* Set trigger timestamp */
@@ -311,6 +318,137 @@ static ssize_t dsb_mode_store(struct device *dev,
  }
  static DEVICE_ATTR_RW(dsb_mode);
  +static ssize_t dsb_edge_ctrl_show(struct device *dev,
+                       struct device_attribute *attr,
+                       char *buf)
+{
+    struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
+    ssize_t size = 0;
+    int i;
+
+    spin_lock(&drvdata->spinlock);
+    for (i = 0; i < TPDM_DSB_MAX_EDCR; i++) {
+        size += sysfs_emit_at(buf, size,
+                  "Index:0x%x Val:0x%x\n", i,
+                  drvdata->dsb->edge_ctrl[i]);
+    }
+    spin_unlock(&drvdata->spinlock);
+    return size;
+}
+
+/*
+ * value 1: Start EDCR register number
+ * value 2: End EDCR register number
+ * value 3: The value need to be written
+ * The EDCR registers can include up to 16 32-bit registers, and each
+ * one can be configured to control up to 16 edge detections(2 bits
+ * control one edge detection). So a total 256 edge detections can be
+ * configured. So the starting number(value 1) and ending number(value 2)
+ * cannot be greater than 256, and value 1 should be less than value 2.
+ * The following values are the rage of value 3.
+ * 0 - Rising edge detection
+ * 1 - Falling edge detection
+ * 2 - Rising and falling edge detection (toggle detection)
+ */
+static ssize_t dsb_edge_ctrl_store(struct device *dev,
+                    struct device_attribute *attr,
+                    const char *buf,
+                    size_t size)
+{
+    struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
+    unsigned long start, end, edge_ctrl;
+    uint32_t val;
+    int i, index, bit, reg;
+
+    if (sscanf(buf, "%lx %lx %lx", &start, &end, &edge_ctrl) != 3)
+        return -EINVAL;
+    if ((start >= TPDM_DSB_MAX_LINES) || (end >= TPDM_DSB_MAX_LINES) ||
+        edge_ctrl > 0x2)
+        return -EPERM;

    Isn't it an error to provide start > end ?
I will add this check in the next patch series.

+
+    spin_lock(&drvdata->spinlock);
+    for (i = start; i <= end; i++) {
+        /*
+         * The 32-bit register has 32 bits(NUM_OF_BITS).
+         * Each one register can be configured to control 16
+         * (NUM_OF_BITS / 2) edge detectioins.
+         */

        /*
         * Each DSB Edge control line requires 2bits.
         * Thus we have 16 lines in a 32bit word.
         */

Could we please define something like:

#define EDCRS_PER_WORD            16
#define EDCR_TO_WORD_IDX(r)        ((r) / EDCRS_PER_WORD)
#define EDCR_TO_WORD_SHIFT(r)        ((r) % EDCRS_PER_WORD)
#define EDCR_TO_WORD_MASK(r)        (0x3 << EDCR_TO_WORD_SHIFT((r)))

Sure, I will update this in the next patch series.
+        reg = i / (NUM_OF_BITS / 2);
+        index = i % (NUM_OF_BITS / 2);
+        bit = index * 2;
+

    reg = EDCR_TO_WORD_IDX(i);
    mask = EDCR_TO_WORD_MASK(i);

    val &= ~mask;
    val |= FIELD_PREP(mask, edge_ctrl);
Got it.

+        val = drvdata->dsb->edge_ctrl[reg];
+        val &= ~GENMASK((bit + 1), bit);
+        val |= (edge_ctrl << bit);


+ drvdata->dsb->edge_ctrl[reg] = val;
+    }
+    spin_unlock(&drvdata->spinlock);
+
+    return size;
+}
+static DEVICE_ATTR_RW(dsb_edge_ctrl);
+
+static ssize_t dsb_edge_ctrl_mask_show(struct device *dev,
+                        struct device_attribute *attr,
+                        char *buf)
+{
+    struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
+    ssize_t size = 0;
+    int i;
+
+    spin_lock(&drvdata->spinlock);
+    for (i = 0; i < TPDM_DSB_MAX_EDCR / 2; i++) {

Why is this not `i < TPDM_DSB_MAX_EDCMR` ?
I will update this in the next patch series.

+        size += sysfs_emit_at(buf, size,
+                  "Index:0x%x Val:0x%x\n", i,
+                  drvdata->dsb->edge_ctrl_mask[i]);
+    }
+    spin_unlock(&drvdata->spinlock);
+    return size;
+}
+
+/*
+ * value 1: Start EDCMR register number
+ * value 2: End EDCMR register number
+ * value 3: The value need to be written
+ */
+static ssize_t dsb_edge_ctrl_mask_store(struct device *dev,
+                         struct device_attribute *attr,
+                         const char *buf,
+                         size_t size)
+{
+    struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
+    unsigned long start, end, val;
+    u32 set;
+    int i, index, reg;
+
+    if (sscanf(buf, "%lx %lx %lx", &start, &end, &val) != 3)
+        return -EINVAL;
+    if ((start >= TPDM_DSB_MAX_LINES) || (end >= TPDM_DSB_MAX_LINES)
+        || (val & ~1UL))
+        return -EPERM;
+
+    spin_lock(&drvdata->spinlock);
+    for (i = start; i <= end; i++) {
+        /*
+         * The 32-bit register has 32 bits(NUM_OF_BITS).
+         * Each one register can be configured to control 32
+         * (NUM_OF_BITS) edge detectioin masks.

minor nit: detection.

You could simply say:
        /*
         * There is 1 bit per DSB Edge Control line.
         * Thus we have 32 lines in a 32bit word.
         */
         reg = i / 32;
I will update this in the next patch series.

+        reg = i / NUM_OF_BITS;
+        index = (i % NUM_OF_BITS);
+
+        set = drvdata->dsb->edge_ctrl_mask[reg];
+        if (val)
+            set |= BIT(index);
+        else
+            set &= ~BIT(index);
+        drvdata->dsb->edge_ctrl_mask[reg] = set;
+    }
+    spin_unlock(&drvdata->spinlock);
+    return size;
+}
+static DEVICE_ATTR_RW(dsb_edge_ctrl_mask);
+
  static ssize_t dsb_trig_type_show(struct device *dev,
                       struct device_attribute *attr,
                       char *buf)
@@ -383,6 +521,8 @@ static DEVICE_ATTR_RW(dsb_trig_ts);
    static struct attribute *tpdm_dsb_attrs[] = {
      &dev_attr_dsb_mode.attr,
+    &dev_attr_dsb_edge_ctrl.attr,
+    &dev_attr_dsb_edge_ctrl_mask.attr,
      &dev_attr_dsb_trig_ts.attr,
      &dev_attr_dsb_trig_type.attr,
      NULL,
diff --git a/drivers/hwtracing/coresight/coresight-tpdm.h b/drivers/hwtracing/coresight/coresight-tpdm.h
index 8fee562..342ef23 100644
--- a/drivers/hwtracing/coresight/coresight-tpdm.h
+++ b/drivers/hwtracing/coresight/coresight-tpdm.h
@@ -12,6 +12,8 @@
  /* DSB Subunit Registers */
  #define TPDM_DSB_CR        (0x780)
  #define TPDM_DSB_TIER        (0x784)
+#define TPDM_DSB_EDCR(n)    (0x808 + (n * 4))
+#define TPDM_DSB_EDCMR(n)    (0x848 + (n * 4))
    /* Enable bit for DSB subunit */
  #define TPDM_DSB_CR_ENA        BIT(0)
@@ -31,6 +33,8 @@
  #define TPDM_DSB_TEST_MODE        GENMASK(11, 9)
  #define TPDM_DSB_HPSEL        GENMASK(6, 2)
  +#define NUM_OF_BITS        32

Please don't use such generic names. Instead define TPDM specific
helper definitions. See above.

I will update this in the next patch series.


Tao


Suzuki


+
  /* TPDM integration test registers */
  #define TPDM_ITATBCNTRL        (0xEF0)
  #define TPDM_ITCNTRL        (0xF00)
@@ -57,14 +61,24 @@
  #define TPDM_PIDR0_DS_IMPDEF    BIT(0)
  #define TPDM_PIDR0_DS_DSB    BIT(1)
  +#define TPDM_DSB_MAX_LINES    256
+/* MAX number of EDCR registers */
+#define TPDM_DSB_MAX_EDCR    16 > +/* MAX number of EDCMR registers */
+#define TPDM_DSB_MAX_EDCMR    8
+
  /**
   * struct dsb_dataset - specifics associated to dsb dataset
   * @mode:             DSB programming mode
+ * @edge_ctrl:        Save value for edge control
+ * @edge_ctrl_mask:   Save value for edge control mask
   * @trig_ts:          Enable/Disable trigger timestamp.
   * @trig_type:        Enable/Disable trigger type.
   */
  struct dsb_dataset {
      u32                mode;
+    u32                edge_ctrl[TPDM_DSB_MAX_EDCR];
+    u32                edge_ctrl_mask[TPDM_DSB_MAX_EDCMR];
      bool            trig_ts;
      bool            trig_type;
  };