[v4,06/10] coresight-tpdm: Add support to configure CMB

Message ID 1705634583-17631-7-git-send-email-quic_taozha@quicinc.com
State New
Headers
Series [v4,01/10] coresight-tpdm: Optimize the store function of tpdm simple dataset |

Commit Message

Tao Zhang Jan. 19, 2024, 3:22 a.m. UTC
  TPDM CMB subunits support two forms of CMB data set element creation:
continuous and trace-on-change collection mode. Continuous change
creates CMB data set elements on every CMBCLK edge. Trace-on-change
creates CMB data set elements only when a new data set element differs
in value from the previous element in a CMB data set. Set CMB_CR.MODE
to 0 for continuous CMB collection mode. Set CMB_CR.MODE to 1 for
trace-on-change CMB collection mode.

Reviewed-by: James Clark <james.clark@arm.com>
Signed-off-by: Tao Zhang <quic_taozha@quicinc.com>
Signed-off-by: Jinlong Mao <quic_jinlmao@quicinc.com>
---
 .../testing/sysfs-bus-coresight-devices-tpdm  | 14 +++++
 drivers/hwtracing/coresight/coresight-tpdm.c  | 61 +++++++++++++++++++
 drivers/hwtracing/coresight/coresight-tpdm.h  | 12 ++++
 3 files changed, 87 insertions(+)
  

Comments

Suzuki K Poulose Jan. 19, 2024, 11:53 a.m. UTC | #1
On 19/01/2024 03:22, Tao Zhang wrote:
> TPDM CMB subunits support two forms of CMB data set element creation:
> continuous and trace-on-change collection mode. Continuous change
> creates CMB data set elements on every CMBCLK edge. Trace-on-change
> creates CMB data set elements only when a new data set element differs
> in value from the previous element in a CMB data set. Set CMB_CR.MODE
> to 0 for continuous CMB collection mode. Set CMB_CR.MODE to 1 for
> trace-on-change CMB collection mode.
> 
> Reviewed-by: James Clark <james.clark@arm.com>
> Signed-off-by: Tao Zhang <quic_taozha@quicinc.com>
> Signed-off-by: Jinlong Mao <quic_jinlmao@quicinc.com>
> ---
>   .../testing/sysfs-bus-coresight-devices-tpdm  | 14 +++++
>   drivers/hwtracing/coresight/coresight-tpdm.c  | 61 +++++++++++++++++++
>   drivers/hwtracing/coresight/coresight-tpdm.h  | 12 ++++
>   3 files changed, 87 insertions(+)
> 
> diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
> index 4dd49b159543..3ae21ccf3f29 100644
> --- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
> +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
> @@ -170,3 +170,17 @@ Contact:	Jinlong Mao (QUIC) <quic_jinlmao@quicinc.com>, Tao Zhang (QUIC) <quic_t
>   Description:
>   		(RW) Set/Get the MSR(mux select register) for the DSB subunit
>   		TPDM.
> +
> +What:		/sys/bus/coresight/devices/<tpdm-name>/cmb_mode
> +Date:		March 2023
> +KernelVersion	6.7
> +Contact:	Jinlong Mao (QUIC) <quic_jinlmao@quicinc.com>, Tao Zhang (QUIC) <quic_taozha@quicinc.com>
> +Description:	(Write) Set the data collection mode of CMB tpdm. Continuous
> +		change creates CMB data set elements on every CMBCLK edge.
> +		Trace-on-change creates CMB data set elements only when a new
> +		data set element differs in value from the previous element
> +		in a CMB data set.
> +
> +		Accepts only one of the 2 values -  0 or 1.
> +		0 : Continuous CMB collection mode.
> +		1 : Trace-on-change CMB collection mode.
> diff --git a/drivers/hwtracing/coresight/coresight-tpdm.c b/drivers/hwtracing/coresight/coresight-tpdm.c
> index 424a2f724d82..b55aee65a856 100644
> --- a/drivers/hwtracing/coresight/coresight-tpdm.c
> +++ b/drivers/hwtracing/coresight/coresight-tpdm.c
> @@ -137,6 +137,18 @@ static umode_t tpdm_dsb_is_visible(struct kobject *kobj,
>   	return 0;
>   }
>   
> +static umode_t tpdm_cmb_is_visible(struct kobject *kobj,
> +				   struct attribute *attr, int n)
> +{
> +	struct device *dev = kobj_to_dev(kobj);
> +	struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
> +
> +	if (drvdata && tpdm_has_cmb_dataset(drvdata))
> +		return attr->mode;
> +
> +	return 0;
> +}
> +
>   static umode_t tpdm_dsb_msr_is_visible(struct kobject *kobj,
>   				       struct attribute *attr, int n)
>   {
> @@ -161,6 +173,9 @@ static void tpdm_reset_datasets(struct tpdm_drvdata *drvdata)
>   		drvdata->dsb->trig_ts = true;
>   		drvdata->dsb->trig_type = false;
>   	}
> +
> +	if (tpdm_has_cmb_dataset(drvdata))

This could simply be gated on drvdata->cmb for extra safety ?

	if (drvdata->cmb)
		
> +		memset(drvdata->cmb, 0, sizeof(struct cmb_dataset));
>   }
>   
>   static void set_dsb_mode(struct tpdm_drvdata *drvdata, u32 *val)
> @@ -389,6 +404,12 @@ static int tpdm_datasets_setup(struct tpdm_drvdata *drvdata)
>   		if (!drvdata->dsb)
>   			return -ENOMEM;
>   	}
> +	if (tpdm_has_cmb_dataset(drvdata) && (!drvdata->cmb)) {
> +		drvdata->cmb = devm_kzalloc(drvdata->dev,
> +						sizeof(*drvdata->cmb), GFP_KERNEL);
> +		if (!drvdata->cmb)
> +			return -ENOMEM;
> +	}
>   	tpdm_reset_datasets(drvdata);
>   
>   	return 0;
> @@ -727,6 +748,35 @@ static ssize_t dsb_trig_ts_store(struct device *dev,
>   }
>   static DEVICE_ATTR_RW(dsb_trig_ts);
>   
> +static ssize_t cmb_mode_show(struct device *dev,
> +			     struct device_attribute *attr,
> +			     char *buf)
> +{
> +	struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
> +
> +	return sysfs_emit(buf, "%x\n",
> +			  drvdata->cmb->trace_mode);

minor nit: Don't need to split the line here. Also, for completeness, 
you need to read it under spinlock, use guard() to unlock implicitly.

> +
> +}
> +
> +static ssize_t cmb_mode_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 trace_mode;
> +
> +	if ((kstrtoul(buf, 0, &trace_mode)) || (trace_mode & ~1UL))

minor nit: drop () around kstrtoul()

Rest looks fine.

Suzuki

> +		return -EINVAL;
> +
> +	spin_lock(&drvdata->spinlock);
> +	drvdata->cmb->trace_mode = trace_mode;
> +	spin_unlock(&drvdata->spinlock);
> +	return size;
> +}
> +static DEVICE_ATTR_RW(cmb_mode);
> +
>   static struct attribute *tpdm_dsb_edge_attrs[] = {
>   	&dev_attr_ctrl_idx.attr,
>   	&dev_attr_ctrl_val.attr,
> @@ -843,6 +893,11 @@ static struct attribute *tpdm_dsb_attrs[] = {
>   	NULL,
>   };
>   
> +static struct attribute *tpdm_cmb_attrs[] = {
> +	&dev_attr_cmb_mode.attr,
> +	NULL,
> +};
> +
>   static struct attribute_group tpdm_dsb_attr_grp = {
>   	.attrs = tpdm_dsb_attrs,
>   	.is_visible = tpdm_dsb_is_visible,
> @@ -872,6 +927,11 @@ static struct attribute_group tpdm_dsb_msr_grp = {
>   	.name = "dsb_msr",
>   };
>   
> +static struct attribute_group tpdm_cmb_attr_grp = {
> +	.attrs = tpdm_cmb_attrs,
> +	.is_visible = tpdm_cmb_is_visible,
> +};
> +
>   static const struct attribute_group *tpdm_attr_grps[] = {
>   	&tpdm_attr_grp,
>   	&tpdm_dsb_attr_grp,
> @@ -879,6 +939,7 @@ static const struct attribute_group *tpdm_attr_grps[] = {
>   	&tpdm_dsb_trig_patt_grp,
>   	&tpdm_dsb_patt_grp,
>   	&tpdm_dsb_msr_grp,
> +	&tpdm_cmb_attr_grp,
>   	NULL,
>   };
>   
> diff --git a/drivers/hwtracing/coresight/coresight-tpdm.h b/drivers/hwtracing/coresight/coresight-tpdm.h
> index a442d9c6e4ac..2af92c270ed1 100644
> --- a/drivers/hwtracing/coresight/coresight-tpdm.h
> +++ b/drivers/hwtracing/coresight/coresight-tpdm.h
> @@ -14,6 +14,8 @@
>   
>   /* Enable bit for CMB subunit */
>   #define TPDM_CMB_CR_ENA		BIT(0)
> +/* Trace collection mode for CMB subunit */
> +#define TPDM_CMB_CR_MODE	BIT(1)
>   
>   /* DSB Subunit Registers */
>   #define TPDM_DSB_CR		(0x780)
> @@ -181,6 +183,14 @@ struct dsb_dataset {
>   	bool			trig_type;
>   };
>   
> +/**
> + * struct cmb_dataset
> + * @trace_mode:       Dataset collection mode
> + */
> +struct cmb_dataset {
> +	u32			trace_mode;
> +};
> +
>   /**
>    * struct tpdm_drvdata - specifics associated to an TPDM component
>    * @base:       memory mapped base address for this component.
> @@ -190,6 +200,7 @@ struct dsb_dataset {
>    * @enable:     enable status of the component.
>    * @datasets:   The datasets types present of the TPDM.
>    * @dsb         Specifics associated to TPDM DSB.
> + * @cmb         Specifics associated to TPDM CMB.
>    * @dsb_msr_num Number of MSR supported by DSB TPDM
>    */
>   
> @@ -201,6 +212,7 @@ struct tpdm_drvdata {
>   	bool			enable;
>   	unsigned long		datasets;
>   	struct dsb_dataset	*dsb;
> +	struct cmb_dataset	*cmb;
>   	u32			dsb_msr_num;
>   };
>
  
Tao Zhang Jan. 22, 2024, 4:27 a.m. UTC | #2
On 1/19/2024 7:53 PM, Suzuki K Poulose wrote:
> On 19/01/2024 03:22, Tao Zhang wrote:
>> TPDM CMB subunits support two forms of CMB data set element creation:
>> continuous and trace-on-change collection mode. Continuous change
>> creates CMB data set elements on every CMBCLK edge. Trace-on-change
>> creates CMB data set elements only when a new data set element differs
>> in value from the previous element in a CMB data set. Set CMB_CR.MODE
>> to 0 for continuous CMB collection mode. Set CMB_CR.MODE to 1 for
>> trace-on-change CMB collection mode.
>>
>> Reviewed-by: James Clark <james.clark@arm.com>
>> Signed-off-by: Tao Zhang <quic_taozha@quicinc.com>
>> Signed-off-by: Jinlong Mao <quic_jinlmao@quicinc.com>
>> ---
>>   .../testing/sysfs-bus-coresight-devices-tpdm  | 14 +++++
>>   drivers/hwtracing/coresight/coresight-tpdm.c  | 61 +++++++++++++++++++
>>   drivers/hwtracing/coresight/coresight-tpdm.h  | 12 ++++
>>   3 files changed, 87 insertions(+)
>>
>> diff --git 
>> a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm 
>> b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
>> index 4dd49b159543..3ae21ccf3f29 100644
>> --- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
>> +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
>> @@ -170,3 +170,17 @@ Contact:    Jinlong Mao (QUIC) 
>> <quic_jinlmao@quicinc.com>, Tao Zhang (QUIC) <quic_t
>>   Description:
>>           (RW) Set/Get the MSR(mux select register) for the DSB subunit
>>           TPDM.
>> +
>> +What: /sys/bus/coresight/devices/<tpdm-name>/cmb_mode
>> +Date:        March 2023
>> +KernelVersion    6.7
>> +Contact:    Jinlong Mao (QUIC) <quic_jinlmao@quicinc.com>, Tao Zhang 
>> (QUIC) <quic_taozha@quicinc.com>
>> +Description:    (Write) Set the data collection mode of CMB tpdm. 
>> Continuous
>> +        change creates CMB data set elements on every CMBCLK edge.
>> +        Trace-on-change creates CMB data set elements only when a new
>> +        data set element differs in value from the previous element
>> +        in a CMB data set.
>> +
>> +        Accepts only one of the 2 values -  0 or 1.
>> +        0 : Continuous CMB collection mode.
>> +        1 : Trace-on-change CMB collection mode.
>> diff --git a/drivers/hwtracing/coresight/coresight-tpdm.c 
>> b/drivers/hwtracing/coresight/coresight-tpdm.c
>> index 424a2f724d82..b55aee65a856 100644
>> --- a/drivers/hwtracing/coresight/coresight-tpdm.c
>> +++ b/drivers/hwtracing/coresight/coresight-tpdm.c
>> @@ -137,6 +137,18 @@ static umode_t tpdm_dsb_is_visible(struct 
>> kobject *kobj,
>>       return 0;
>>   }
>>   +static umode_t tpdm_cmb_is_visible(struct kobject *kobj,
>> +                   struct attribute *attr, int n)
>> +{
>> +    struct device *dev = kobj_to_dev(kobj);
>> +    struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
>> +
>> +    if (drvdata && tpdm_has_cmb_dataset(drvdata))
>> +        return attr->mode;
>> +
>> +    return 0;
>> +}
>> +
>>   static umode_t tpdm_dsb_msr_is_visible(struct kobject *kobj,
>>                          struct attribute *attr, int n)
>>   {
>> @@ -161,6 +173,9 @@ static void tpdm_reset_datasets(struct 
>> tpdm_drvdata *drvdata)
>>           drvdata->dsb->trig_ts = true;
>>           drvdata->dsb->trig_type = false;
>>       }
>> +
>> +    if (tpdm_has_cmb_dataset(drvdata))
>
> This could simply be gated on drvdata->cmb for extra safety ?
>
>     if (drvdata->cmb)
Sure, can I also use "if (drvdata->dsb) " instead of "if 
(tpdm_has_dsb_dataset(drvdata))" and update in the same patch?
>
>> +        memset(drvdata->cmb, 0, sizeof(struct cmb_dataset));
>>   }
>>     static void set_dsb_mode(struct tpdm_drvdata *drvdata, u32 *val)
>> @@ -389,6 +404,12 @@ static int tpdm_datasets_setup(struct 
>> tpdm_drvdata *drvdata)
>>           if (!drvdata->dsb)
>>               return -ENOMEM;
>>       }
>> +    if (tpdm_has_cmb_dataset(drvdata) && (!drvdata->cmb)) {
>> +        drvdata->cmb = devm_kzalloc(drvdata->dev,
>> +                        sizeof(*drvdata->cmb), GFP_KERNEL);
>> +        if (!drvdata->cmb)
>> +            return -ENOMEM;
>> +    }
>>       tpdm_reset_datasets(drvdata);
>>         return 0;
>> @@ -727,6 +748,35 @@ static ssize_t dsb_trig_ts_store(struct device 
>> *dev,
>>   }
>>   static DEVICE_ATTR_RW(dsb_trig_ts);
>>   +static ssize_t cmb_mode_show(struct device *dev,
>> +                 struct device_attribute *attr,
>> +                 char *buf)
>> +{
>> +    struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
>> +
>> +    return sysfs_emit(buf, "%x\n",
>> +              drvdata->cmb->trace_mode);
>
> minor nit: Don't need to split the line here. Also, for completeness, 
> you need to read it under spinlock, use guard() to unlock implicitly.

Sure, I will not split the line here in the next patch series.

I didn't add spinlock here because the show function only read the value.

Do you mean I need to add the spinlock to all of the show function?

>
>> +
>> +}
>> +
>> +static ssize_t cmb_mode_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 trace_mode;
>> +
>> +    if ((kstrtoul(buf, 0, &trace_mode)) || (trace_mode & ~1UL))
>
> minor nit: drop () around kstrtoul()

Sure, I will update in the next patch series.


Best,

Tao

>
> Rest looks fine.
>
> Suzuki
>
>> +        return -EINVAL;
>> +
>> +    spin_lock(&drvdata->spinlock);
>> +    drvdata->cmb->trace_mode = trace_mode;
>> +    spin_unlock(&drvdata->spinlock);
>> +    return size;
>> +}
>> +static DEVICE_ATTR_RW(cmb_mode);
>> +
>>   static struct attribute *tpdm_dsb_edge_attrs[] = {
>>       &dev_attr_ctrl_idx.attr,
>>       &dev_attr_ctrl_val.attr,
>> @@ -843,6 +893,11 @@ static struct attribute *tpdm_dsb_attrs[] = {
>>       NULL,
>>   };
>>   +static struct attribute *tpdm_cmb_attrs[] = {
>> +    &dev_attr_cmb_mode.attr,
>> +    NULL,
>> +};
>> +
>>   static struct attribute_group tpdm_dsb_attr_grp = {
>>       .attrs = tpdm_dsb_attrs,
>>       .is_visible = tpdm_dsb_is_visible,
>> @@ -872,6 +927,11 @@ static struct attribute_group tpdm_dsb_msr_grp = {
>>       .name = "dsb_msr",
>>   };
>>   +static struct attribute_group tpdm_cmb_attr_grp = {
>> +    .attrs = tpdm_cmb_attrs,
>> +    .is_visible = tpdm_cmb_is_visible,
>> +};
>> +
>>   static const struct attribute_group *tpdm_attr_grps[] = {
>>       &tpdm_attr_grp,
>>       &tpdm_dsb_attr_grp,
>> @@ -879,6 +939,7 @@ static const struct attribute_group 
>> *tpdm_attr_grps[] = {
>>       &tpdm_dsb_trig_patt_grp,
>>       &tpdm_dsb_patt_grp,
>>       &tpdm_dsb_msr_grp,
>> +    &tpdm_cmb_attr_grp,
>>       NULL,
>>   };
>>   diff --git a/drivers/hwtracing/coresight/coresight-tpdm.h 
>> b/drivers/hwtracing/coresight/coresight-tpdm.h
>> index a442d9c6e4ac..2af92c270ed1 100644
>> --- a/drivers/hwtracing/coresight/coresight-tpdm.h
>> +++ b/drivers/hwtracing/coresight/coresight-tpdm.h
>> @@ -14,6 +14,8 @@
>>     /* Enable bit for CMB subunit */
>>   #define TPDM_CMB_CR_ENA        BIT(0)
>> +/* Trace collection mode for CMB subunit */
>> +#define TPDM_CMB_CR_MODE    BIT(1)
>>     /* DSB Subunit Registers */
>>   #define TPDM_DSB_CR        (0x780)
>> @@ -181,6 +183,14 @@ struct dsb_dataset {
>>       bool            trig_type;
>>   };
>>   +/**
>> + * struct cmb_dataset
>> + * @trace_mode:       Dataset collection mode
>> + */
>> +struct cmb_dataset {
>> +    u32            trace_mode;
>> +};
>> +
>>   /**
>>    * struct tpdm_drvdata - specifics associated to an TPDM component
>>    * @base:       memory mapped base address for this component.
>> @@ -190,6 +200,7 @@ struct dsb_dataset {
>>    * @enable:     enable status of the component.
>>    * @datasets:   The datasets types present of the TPDM.
>>    * @dsb         Specifics associated to TPDM DSB.
>> + * @cmb         Specifics associated to TPDM CMB.
>>    * @dsb_msr_num Number of MSR supported by DSB TPDM
>>    */
>>   @@ -201,6 +212,7 @@ struct tpdm_drvdata {
>>       bool            enable;
>>       unsigned long        datasets;
>>       struct dsb_dataset    *dsb;
>> +    struct cmb_dataset    *cmb;
>>       u32            dsb_msr_num;
>>   };
>
> _______________________________________________
> CoreSight mailing list -- coresight@lists.linaro.org
> To unsubscribe send an email to coresight-leave@lists.linaro.org
  

Patch

diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
index 4dd49b159543..3ae21ccf3f29 100644
--- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
+++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
@@ -170,3 +170,17 @@  Contact:	Jinlong Mao (QUIC) <quic_jinlmao@quicinc.com>, Tao Zhang (QUIC) <quic_t
 Description:
 		(RW) Set/Get the MSR(mux select register) for the DSB subunit
 		TPDM.
+
+What:		/sys/bus/coresight/devices/<tpdm-name>/cmb_mode
+Date:		March 2023
+KernelVersion	6.7
+Contact:	Jinlong Mao (QUIC) <quic_jinlmao@quicinc.com>, Tao Zhang (QUIC) <quic_taozha@quicinc.com>
+Description:	(Write) Set the data collection mode of CMB tpdm. Continuous
+		change creates CMB data set elements on every CMBCLK edge.
+		Trace-on-change creates CMB data set elements only when a new
+		data set element differs in value from the previous element
+		in a CMB data set.
+
+		Accepts only one of the 2 values -  0 or 1.
+		0 : Continuous CMB collection mode.
+		1 : Trace-on-change CMB collection mode.
diff --git a/drivers/hwtracing/coresight/coresight-tpdm.c b/drivers/hwtracing/coresight/coresight-tpdm.c
index 424a2f724d82..b55aee65a856 100644
--- a/drivers/hwtracing/coresight/coresight-tpdm.c
+++ b/drivers/hwtracing/coresight/coresight-tpdm.c
@@ -137,6 +137,18 @@  static umode_t tpdm_dsb_is_visible(struct kobject *kobj,
 	return 0;
 }
 
+static umode_t tpdm_cmb_is_visible(struct kobject *kobj,
+				   struct attribute *attr, int n)
+{
+	struct device *dev = kobj_to_dev(kobj);
+	struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
+
+	if (drvdata && tpdm_has_cmb_dataset(drvdata))
+		return attr->mode;
+
+	return 0;
+}
+
 static umode_t tpdm_dsb_msr_is_visible(struct kobject *kobj,
 				       struct attribute *attr, int n)
 {
@@ -161,6 +173,9 @@  static void tpdm_reset_datasets(struct tpdm_drvdata *drvdata)
 		drvdata->dsb->trig_ts = true;
 		drvdata->dsb->trig_type = false;
 	}
+
+	if (tpdm_has_cmb_dataset(drvdata))
+		memset(drvdata->cmb, 0, sizeof(struct cmb_dataset));
 }
 
 static void set_dsb_mode(struct tpdm_drvdata *drvdata, u32 *val)
@@ -389,6 +404,12 @@  static int tpdm_datasets_setup(struct tpdm_drvdata *drvdata)
 		if (!drvdata->dsb)
 			return -ENOMEM;
 	}
+	if (tpdm_has_cmb_dataset(drvdata) && (!drvdata->cmb)) {
+		drvdata->cmb = devm_kzalloc(drvdata->dev,
+						sizeof(*drvdata->cmb), GFP_KERNEL);
+		if (!drvdata->cmb)
+			return -ENOMEM;
+	}
 	tpdm_reset_datasets(drvdata);
 
 	return 0;
@@ -727,6 +748,35 @@  static ssize_t dsb_trig_ts_store(struct device *dev,
 }
 static DEVICE_ATTR_RW(dsb_trig_ts);
 
+static ssize_t cmb_mode_show(struct device *dev,
+			     struct device_attribute *attr,
+			     char *buf)
+{
+	struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
+
+	return sysfs_emit(buf, "%x\n",
+			  drvdata->cmb->trace_mode);
+
+}
+
+static ssize_t cmb_mode_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 trace_mode;
+
+	if ((kstrtoul(buf, 0, &trace_mode)) || (trace_mode & ~1UL))
+		return -EINVAL;
+
+	spin_lock(&drvdata->spinlock);
+	drvdata->cmb->trace_mode = trace_mode;
+	spin_unlock(&drvdata->spinlock);
+	return size;
+}
+static DEVICE_ATTR_RW(cmb_mode);
+
 static struct attribute *tpdm_dsb_edge_attrs[] = {
 	&dev_attr_ctrl_idx.attr,
 	&dev_attr_ctrl_val.attr,
@@ -843,6 +893,11 @@  static struct attribute *tpdm_dsb_attrs[] = {
 	NULL,
 };
 
+static struct attribute *tpdm_cmb_attrs[] = {
+	&dev_attr_cmb_mode.attr,
+	NULL,
+};
+
 static struct attribute_group tpdm_dsb_attr_grp = {
 	.attrs = tpdm_dsb_attrs,
 	.is_visible = tpdm_dsb_is_visible,
@@ -872,6 +927,11 @@  static struct attribute_group tpdm_dsb_msr_grp = {
 	.name = "dsb_msr",
 };
 
+static struct attribute_group tpdm_cmb_attr_grp = {
+	.attrs = tpdm_cmb_attrs,
+	.is_visible = tpdm_cmb_is_visible,
+};
+
 static const struct attribute_group *tpdm_attr_grps[] = {
 	&tpdm_attr_grp,
 	&tpdm_dsb_attr_grp,
@@ -879,6 +939,7 @@  static const struct attribute_group *tpdm_attr_grps[] = {
 	&tpdm_dsb_trig_patt_grp,
 	&tpdm_dsb_patt_grp,
 	&tpdm_dsb_msr_grp,
+	&tpdm_cmb_attr_grp,
 	NULL,
 };
 
diff --git a/drivers/hwtracing/coresight/coresight-tpdm.h b/drivers/hwtracing/coresight/coresight-tpdm.h
index a442d9c6e4ac..2af92c270ed1 100644
--- a/drivers/hwtracing/coresight/coresight-tpdm.h
+++ b/drivers/hwtracing/coresight/coresight-tpdm.h
@@ -14,6 +14,8 @@ 
 
 /* Enable bit for CMB subunit */
 #define TPDM_CMB_CR_ENA		BIT(0)
+/* Trace collection mode for CMB subunit */
+#define TPDM_CMB_CR_MODE	BIT(1)
 
 /* DSB Subunit Registers */
 #define TPDM_DSB_CR		(0x780)
@@ -181,6 +183,14 @@  struct dsb_dataset {
 	bool			trig_type;
 };
 
+/**
+ * struct cmb_dataset
+ * @trace_mode:       Dataset collection mode
+ */
+struct cmb_dataset {
+	u32			trace_mode;
+};
+
 /**
  * struct tpdm_drvdata - specifics associated to an TPDM component
  * @base:       memory mapped base address for this component.
@@ -190,6 +200,7 @@  struct dsb_dataset {
  * @enable:     enable status of the component.
  * @datasets:   The datasets types present of the TPDM.
  * @dsb         Specifics associated to TPDM DSB.
+ * @cmb         Specifics associated to TPDM CMB.
  * @dsb_msr_num Number of MSR supported by DSB TPDM
  */
 
@@ -201,6 +212,7 @@  struct tpdm_drvdata {
 	bool			enable;
 	unsigned long		datasets;
 	struct dsb_dataset	*dsb;
+	struct cmb_dataset	*cmb;
 	u32			dsb_msr_num;
 };