Re: [PATCH v4 07/11] coresight-tpdm: Add nodes for dsb edge control

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On 27/04/2023 10:00, 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   |  32 +++++
  drivers/hwtracing/coresight/coresight-tpdm.c       | 135 ++++++++++++++++++++-
  drivers/hwtracing/coresight/coresight-tpdm.h       |  21 ++++
  3 files changed, 187 insertions(+), 1 deletion(-)

diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
index 348e167..a57f000 100644
--- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
+++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
@@ -60,3 +60,35 @@ Description:
  		Bit[3] : Set to 0 for low performance mode.
  				 Set to 1 for high performance mode.
  		Bit[4:8] : Select byte lane for high performance mode.
+
+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:
+		Read/Write a set of the edge control registers of the DSB
+		in TPDM.
+
+		Expected format is the following:
+		<integer1> <integer2> <integer3>
+
+		Where:
+		<integer1> : Start EDCR register number
+		<integer2> : End EDCR register number
+		<integer3> : The value need to be written
+
+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:
+		Read/Write a set of the edge control mask registers of the
+		DSB in TPDM.
+
+		Expected format is the following:
+		<integer1> <integer2> <integer3>
+
+		Where:
+		<integer1> : Start EDCMR register number
+		<integer2> : End EDCMR register number
+		<integer3> : The value need to be written
diff --git a/drivers/hwtracing/coresight/coresight-tpdm.c b/drivers/hwtracing/coresight/coresight-tpdm.c
index 1bacaa5..a40e458 100644
--- a/drivers/hwtracing/coresight/coresight-tpdm.c
+++ b/drivers/hwtracing/coresight/coresight-tpdm.c
@@ -80,7 +80,14 @@ 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));

Do all TPDM DSBs have MAX_EDCR registers ? Or some have less than that ?
If it is latter, do we need special care to avoid writing to inexistent
registers ?

val = readl_relaxed(drvdata->base + TPDM_DSB_TIER);
  	/* Set trigger timestamp */
@@ -313,6 +320,130 @@ 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]);

It may be safe, but please add a check to make sure that we don't
overflow. At least bail out when we hit a return of 0, indicating
reached the end of buffer.

+	}
+	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 val, mask, start, end, edge_ctrl, edge_ctrl_shift;
+	int i, 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) ||
+	    (start > end) || (edge_ctrl > 0x2))
+		return -EPERM;
+
+	spin_lock(&drvdata->spinlock);
+	for (i = start; i <= end; i++) {
+		/*
+		 * There are 2 bit per DSB Edge Control line.
+		 * Thus we have 16 lines in a 32bit word.
+		 */
+		reg = EDCR_TO_WORD_IDX(i);
+		mask = EDCR_TO_WORD_MASK(i);
+		val = drvdata->dsb->edge_ctrl[reg];

+		edge_ctrl_shift = EDCR_TO_WORD_VAL(edge_ctrl, i);
+		bitmap_replace(&val, &val, &edge_ctrl_shift, &mask, 32);

Could we simply do :

		reg &= ~mask;
		reg |= FIELD_PREP(mask, edge_ctrl);


+		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_EDCMR; i++) {
+		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, reg;
+
+	if (sscanf(buf, "%lx %lx %lx", &start, &end, &val) != 3)
+		return -EINVAL;
+	if ((start >= TPDM_DSB_MAX_LINES) || (end >= TPDM_DSB_MAX_LINES)
+		|| (start > end) || (val & ~1UL))
+		return -EPERM;
+
+	spin_lock(&drvdata->spinlock);
+	for (i = start; i <= end; i++) {
+		/*
+		 * There is 1 bit per DSB Edge Control Mark line.
+		 * Thus we have 32 lines in a 32bit word.
+		 */
+		reg = EDCMR_TO_WORD_IDX(i);
+		set = drvdata->dsb->edge_ctrl_mask[reg];
+		if (val)
+			set |= BIT(EDCR_TO_WORD_SHIFT(i));
+		else
+			set &= ~BIT(EDCR_TO_WORD_SHIFT(i));
+		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)
  {
@@ -385,6 +516,8 @@ 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 79df07e..f25dcdec 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)
@@ -34,6 +36,15 @@
  #define TPDM_DSB_TEST_MODE		GENMASK(10, 9)
  #define TPDM_DSB_HPSEL		GENMASK(6, 2)
+#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) * 2)
+#define EDCR_TO_WORD_VAL(val, r)	(val << EDCR_TO_WORD_SHIFT(r))
+#define EDCR_TO_WORD_MASK(r)		EDCR_TO_WORD_VAL(0x3, r)

minor nit: add a new line here please

+#define EDCMRS_PER_WORD				32
+#define EDCMR_TO_WORD_IDX(r)		((r) / EDCMRS_PER_WORD)
+#define EDCMR_TO_WORD_SHIFT(r)		((r) % EDCMRS_PER_WORD)
+
  /* TPDM integration test registers */
  #define TPDM_ITATBCNTRL		(0xEF0)
  #define TPDM_ITCNTRL		(0xF00)
@@ -60,14 +71,24 @@
  #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];

minor nit: Please align it with the fields below.

  	bool			trig_ts;
  	bool			trig_type;
  };

Suzuki



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