Re: [PATCH v7 10/13] coresight-tpdm: Add nodes to configure pattern match output

[Suzuki K Poulose <suzuki.poulose@arm.com>]

On 25/07/2023 08:15, Tao Zhang wrote:
> Add nodes to configure trigger pattern and trigger pattern mask.
> Each DSB subunit TPDM has maximum of n(n<7) XPR registers to
> configure trigger pattern match output. Eight 32 bit registers
> providing DSB interface trigger output pattern match comparison.
> And each DSB subunit TPDM has maximum of m(m<7) XPMR registers to
> configure trigger pattern mask match output. Eight 32 bit
> registers providing DSB interface trigger output pattern match
> mask.
> 
> Signed-off-by: Tao Zhang <quic_taozha@quicinc.com>
> ---
>   .../ABI/testing/sysfs-bus-coresight-devices-tpdm   |  34 +++++-
>   drivers/hwtracing/coresight/coresight-tpdm.c       | 118 +++++++++++++++++++++
>   drivers/hwtracing/coresight/coresight-tpdm.h       |  10 ++
>   3 files changed, 161 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
> index a4550c5..66f9582 100644
> --- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
> +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
> @@ -98,4 +98,36 @@ Description:
>   		should be written first to configure the index number of the edge
>   		detection which needs to be masked.
>   
> -		Accepts only one of the 2 values -  0 or 1.
> \ No newline at end of file
> +		Accepts only one of the 2 values -  0 or 1.
> +
> +What:		/sys/bus/coresight/devices/<tpdm-name>/dsb_trig_patt_idx
> +Date:		March 2023
> +KernelVersion	6.5
> +Contact:	Jinlong Mao (QUIC) <quic_jinlmao@quicinc.com>, Tao Zhang (QUIC) <quic_taozha@quicinc.com>
> +Description:
> +		Read/Write the index number of the trigger pattern value of DSB
> +		tpdm. Since there are at most 8 XPR and XPMR registers for the
> +		trigger parttern, this value ranges from 0 to 7.
> +
> +What:		/sys/bus/coresight/devices/<tpdm-name>/dsb_trig_patt_val
> +Date:		March 2023
> +KernelVersion	6.5
> +Contact:	Jinlong Mao (QUIC) <quic_jinlmao@quicinc.com>, Tao Zhang (QUIC) <quic_taozha@quicinc.com>
> +Description:
> +		Read a set of the trigger pattern values of the DSB TPDM.
> +		Write a data to configure the trigger pattern corresponding to
> +		the index number. Before writing data to this sysfs file,
> +		"dsb_trig_patt_idx" should be written first to configure the
> +		index number of the trigger pattern which needs to be configured.
> +
> +What:		/sys/bus/coresight/devices/<tpdm-name>/dsb_trig_patt_mask
> +Date:		March 2023
> +KernelVersion	6.5
> +Contact:	Jinlong Mao (QUIC) <quic_jinlmao@quicinc.com>, Tao Zhang (QUIC) <quic_taozha@quicinc.com>
> +Description:
> +		Read a set of the trigger pattern mask of the DSB TPDM.
> +		Write a data to configure the trigger pattern mask corresponding
> +		to the index number. Before writing data to this sysfs file,
> +		"dsb_trig_patt_idx" should be written first to configure the
> +		index number of the trigger pattern mask which needs to be
> +		configured.
> \ No newline at end of file
> diff --git a/drivers/hwtracing/coresight/coresight-tpdm.c b/drivers/hwtracing/coresight/coresight-tpdm.c
> index 98fd6ab..1c32d27 100644
> --- a/drivers/hwtracing/coresight/coresight-tpdm.c
> +++ b/drivers/hwtracing/coresight/coresight-tpdm.c
> @@ -80,6 +80,13 @@ static void tpdm_enable_dsb(struct tpdm_drvdata *drvdata)
>   		writel_relaxed(drvdata->dsb->edge_ctrl_mask[i],
>   			   drvdata->base + TPDM_DSB_EDCMR(i));
>   
> +	for (i = 0; i < TPDM_DSB_MAX_PATT; i++) {
> +		writel_relaxed(drvdata->dsb->trig_patt[i],
> +			    drvdata->base + TPDM_DSB_XPR(i));
> +		writel_relaxed(drvdata->dsb->trig_patt_mask[i],
> +			    drvdata->base + TPDM_DSB_XPMR(i));
> +	}
> +
>   	val = readl_relaxed(drvdata->base + TPDM_DSB_TIER);
>   	/* Set trigger timestamp */
>   	if (drvdata->dsb->trig_ts)
> @@ -455,6 +462,114 @@ static ssize_t dsb_edge_ctrl_mask_store(struct device *dev,
>   }
>   static DEVICE_ATTR_RW(dsb_edge_ctrl_mask);
>   
> +static ssize_t dsb_trig_patt_idx_show(struct device *dev,
> +					   struct device_attribute *attr,
> +					   char *buf)
> +{
> +	struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
> +
> +	return sysfs_emit(buf, "%u\n",
> +			 (unsigned int)drvdata->dsb->trig_patt_idx);
> +}
> +
> +static ssize_t dsb_trig_patt_idx_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 index;
> +
> +	if (kstrtoul(buf, 0, &index))
> +		return -EINVAL;
> +	if (index >= TPDM_DSB_MAX_PATT)
> +		return -EPERM;
> +
> +	spin_lock(&drvdata->spinlock);
> +	drvdata->dsb->trig_patt_idx = index;
> +	spin_unlock(&drvdata->spinlock);
> +	return size;
> +}
> +static DEVICE_ATTR_RW(dsb_trig_patt_idx);
> +
> +static ssize_t dsb_trig_patt_val_show(struct device *dev,
> +					   struct device_attribute *attr,
> +					   char *buf)
> +{
> +	struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
> +	ssize_t size = 0;
> +	unsigned long bytes;
> +	int i = 0;
> +
> +	spin_lock(&drvdata->spinlock);
> +	for (i = 0; i < TPDM_DSB_MAX_PATT; i++) {
> +		bytes = sysfs_emit_at(buf, size,
> +				  "Value: 0x%x\n", drvdata->dsb->trig_patt[i]);
> +		if (bytes <= 0)
> +			break;
> +		size += bytes;
> +	}
> +	spin_unlock(&drvdata->spinlock);
> +	return size;
> +}
> +
> +static ssize_t dsb_trig_patt_val_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;
> +
> +	if (kstrtoul(buf, 0, &val))
> +		return -EINVAL;
> +
> +	spin_lock(&drvdata->spinlock);
> +	drvdata->dsb->trig_patt[drvdata->dsb->trig_patt_idx] = val;
> +	spin_unlock(&drvdata->spinlock);
> +	return size;
> +}
> +static DEVICE_ATTR_RW(dsb_trig_patt_val);
> +
> +static ssize_t dsb_trig_patt_mask_show(struct device *dev,
> +					    struct device_attribute *attr,
> +					    char *buf)
> +{
> +	struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
> +	ssize_t size = 0;
> +	unsigned long bytes;
> +	int i = 0;
> +
> +	spin_lock(&drvdata->spinlock);
> +	for (i = 0; i < TPDM_DSB_MAX_PATT; i++) {
> +		bytes = sysfs_emit_at(buf, size,
> +			  "Value: 0x%x\n", drvdata->dsb->trig_patt_mask[i]);

As mentioned above, please stick to single value. In this case, we could 
simply expose :

dsb_trig_patt_mask0..7 as RW and directly let the user set/get the 
values and get rid of the idx.

You may be able to use an device_ext_attribute to store the index and 
use a single function to support all registers.

Suzuki