Re: [PATCH v7 09/13] coresight-tpdm: Add nodes for dsb edge control

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

On 25/07/2023 08:15, 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.
> 
> Add the nodes to configure DSB edge control and DSB edge control
> mask. Each DSB subunit TPDM maximum of 256 edge detections can be
> configured. The index and value sysfs files need to be paired and
> written to order. The index sysfs file is to set the index number
> of the edge detection which needs to be configured. And the value
> sysfs file is to set the control or mask for the edge detection.
> DSB edge detection control should be set as the following values.
> 00: Rising edge detection
> 01: Falling edge detection
> 10: Rising and falling edge detection (toggle detection)
> And DSB edge mask should be set as 0 or 1.
> Each DSB subunit TPDM has maximum of n(n<16) EDCR resgisters to
> configure edge control. And each DSB subunit TPDM has maximum of
> m(m<8) ECDMR registers to configure mask.
> 
> Signed-off-by: Tao Zhang <quic_taozha@quicinc.com>
> ---
>   .../ABI/testing/sysfs-bus-coresight-devices-tpdm   |  39 +++++
>   drivers/hwtracing/coresight/coresight-tpdm.c       | 158 ++++++++++++++++++++-
>   drivers/hwtracing/coresight/coresight-tpdm.h       |  30 +++-
>   3 files changed, 223 insertions(+), 4 deletions(-)
> 
> diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
> index 2a82cd0..a4550c5 100644
> --- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
> +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
> @@ -60,3 +60,42 @@ 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_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 edge detection for the DSB
> +		subunit TPDM. Since there are at most 256 edge detections, this
> +		value ranges from 0 to 255.
> +
> +What:		/sys/bus/coresight/devices/<tpdm-name>/dsb_edge_ctrl_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 edge control registers of the DSB in TPDM.
> +		Write a data to control the edge detection corresponding to
> +		the index number. Before writing data to this sysfs file,
> +		"dsb_edge_ctrl_idx" should be written first to configure the
> +		index number of the edge detection which needs to be controlled.
> +
> +		Accepts only one of the following values.
> +		0 - Rising edge detection
> +		1 - Falling edge detection
> +		2 - Rising and falling edge detection (toggle detection)
> +
> +
> +What:		/sys/bus/coresight/devices/<tpdm-name>/dsb_edge_ctrl_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 edge control mask registers of the DSB in TPDM.
> +		Write a data to mask the edge detection corresponding to the index
> +		number. Before writing data to this sysfs file, "dsb_edge_ctrl_idx"
> +		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
> diff --git a/drivers/hwtracing/coresight/coresight-tpdm.c b/drivers/hwtracing/coresight/coresight-tpdm.c
> index c38760b..98fd6ab 100644
> --- a/drivers/hwtracing/coresight/coresight-tpdm.c
> +++ b/drivers/hwtracing/coresight/coresight-tpdm.c
> @@ -71,7 +71,14 @@ static void set_dsb_perf_mode(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 */
> @@ -302,6 +309,152 @@ static ssize_t dsb_mode_store(struct device *dev,
>   }
>   static DEVICE_ATTR_RW(dsb_mode);
>   
> +static ssize_t dsb_edge_ctrl_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->edge_ctrl_idx);
> +}
> +
> +/*
> + * 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. This function provides a way to set the index number of
> + * the edge detection which needs to be configured.
> + */
> +static ssize_t dsb_edge_ctrl_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 val;
> +
> +	if ((kstrtoul(buf, 0, &val)) || (val >= TPDM_DSB_MAX_LINES))
> +		return -EINVAL;
> +
> +	spin_lock(&drvdata->spinlock);
> +	drvdata->dsb->edge_ctrl_idx = val;
> +	spin_unlock(&drvdata->spinlock);
> +
> +	return size;
> +}
> +static DEVICE_ATTR_RW(dsb_edge_ctrl_idx);
> +
> +static ssize_t dsb_edge_ctrl_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;
> +
> +	spin_lock(&drvdata->spinlock);
> +	for (i = 0; i < TPDM_DSB_MAX_EDCR; i++) {
> +		bytes = sysfs_emit_at(buf, size,
> +				  "Val:0x%x\n", drvdata->dsb->edge_ctrl[i]);

This feels a bit odd. edget_ctrl_val allows storing one "edge ctrl"
value, while "show"ing all EDCR values. We could split them to :

Read only sysfs files:

dsb_edcr0 ... dsb_edcr15

for each EDCR register (similarly for the mask)

and may be show the specific edge_ctrl_line for with the above function 
for selected index.

> +		if (bytes <= 0)
> +			break;
> +		size += bytes;
> +	}
> +	spin_unlock(&drvdata->spinlock);
> +	return size;
> +}
> +
> +/*
> + * This function is used to control the edge detection according
> + * to the index number that has been set.
> + * "edge_ctrl" should be one of the following values.
> + * 0 - Rising edge detection
> + * 1 - Falling edge detection
> + * 2 - Rising and falling edge detection (toggle detection)
> + */
> +static ssize_t dsb_edge_ctrl_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, mask, edge_ctrl;
> +	int reg;
> +
> +	if ((kstrtoul(buf, 0, &edge_ctrl)) || (edge_ctrl > 0x2))
> +		return -EINVAL;
> +
> +	spin_lock(&drvdata->spinlock);
> +	/*
> +	 * There are 2 bit per DSB Edge Control line.
> +	 * Thus we have 16 lines in a 32bit word.
> +	 */
> +	reg = EDCR_TO_WORD_IDX(drvdata->dsb->edge_ctrl_idx);
> +	mask = EDCR_TO_WORD_MASK(drvdata->dsb->edge_ctrl_idx);
> +	val = drvdata->dsb->edge_ctrl[reg];
> +	val &= ~EDCR_TO_WORD_MASK(drvdata->dsb->edge_ctrl_idx);
> +	val |= EDCR_TO_WORD_VAL(edge_ctrl, drvdata->dsb->edge_ctrl_idx);
> +	drvdata->dsb->edge_ctrl[reg] = val;
> +	spin_unlock(&drvdata->spinlock);
> +
> +	return size;
> +}
> +static DEVICE_ATTR_RW(dsb_edge_ctrl_val);

This can be WO attribute to write to a given line.

> +
> +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;
> +	unsigned long bytes;
> +	int i;
> +
> +	spin_lock(&drvdata->spinlock);
> +	for (i = 0; i < TPDM_DSB_MAX_EDCMR; i++) {
> +		bytes = sysfs_emit_at(buf, size,
> +				  "Val:0x%x\n", drvdata->dsb->edge_ctrl_mask[i]);

As mentioned above, please don't do this. One value per file. Add

dsb_edcmr0..dsb_edcmr7

and print only the selected index mask for this function.

> +		if (bytes <= 0)
> +			break;
> +		size += bytes;
> +	}
> +	spin_unlock(&drvdata->spinlock);
> +	return size;
> +}
> +
> +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 val;
> +	u32 set;
> +	int reg;
> +
> +	if ((kstrtoul(buf, 0, &val)) || (val & ~1UL))
> +		return -EINVAL;
> +
> +	spin_lock(&drvdata->spinlock);
> +	/*
> +	 * There is 1 bit per DSB Edge Control Mark line.
> +	 * Thus we have 32 lines in a 32bit word.
> +	 */
> +	reg = EDCMR_TO_WORD_IDX(drvdata->dsb->edge_ctrl_idx);
> +	set = drvdata->dsb->edge_ctrl_mask[reg];
> +	if (val)
> +		set |= BIT(EDCMR_TO_WORD_SHIFT(drvdata->dsb->edge_ctrl_idx));
> +	else
> +		set &= ~BIT(EDCMR_TO_WORD_SHIFT(drvdata->dsb->edge_ctrl_idx));
> +		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)
>   {
> @@ -374,6 +527,9 @@ static DEVICE_ATTR_RW(dsb_trig_ts);
>   
>   static struct attribute *tpdm_dsb_attrs[] = {
>   	&dev_attr_dsb_mode.attr,
> +	&dev_attr_dsb_edge_ctrl_idx.attr,
> +	&dev_attr_dsb_edge_ctrl_val.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 49fffb1..4afdb29 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 +36,16 @@
>   #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)
> +
> +#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 +72,26 @@
>   #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
> - * @trig_ts:          Enable/Disable trigger timestamp.
> - * @trig_type:        Enable/Disable trigger type.
> + * @mode:               DSB programming mode
> + * @edge_ctrl_idx       Index number of the edge control
> + * @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_idx;
> +	u32				edge_ctrl[TPDM_DSB_MAX_EDCR];
> +	u32				edge_ctrl_mask[TPDM_DSB_MAX_EDCMR];

Please keep them aligned with the rest of the fields.

>   	bool			trig_ts;
>   	bool			trig_type;

Suzuki


>   };