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Date:   Fri, 1 Sep 2023 15:07:35 +0100
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Subject: Re: [PATCH v8 09/13] coresight-tpdm: Add nodes for dsb edge control
To:     Tao Zhang <quic_taozha@quicinc.com>,
        Mathieu Poirier <mathieu.poirier@linaro.org>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Konrad Dybcio <konradybcio@gmail.com>,
        Mike Leach <mike.leach@linaro.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>
Cc:     Jinlong Mao <quic_jinlmao@quicinc.com>,
        Leo Yan <leo.yan@linaro.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
        Tingwei Zhang <quic_tingweiz@quicinc.com>,
        Yuanfang Zhang <quic_yuanfang@quicinc.com>,
        Trilok Soni <quic_tsoni@quicinc.com>,
        Hao Zhang <quic_hazha@quicinc.com>,
        linux-arm-msm@vger.kernel.org, andersson@kernel.org
References: <1692681973-20764-1-git-send-email-quic_taozha@quicinc.com>
 <1692681973-20764-10-git-send-email-quic_taozha@quicinc.com>
From:   Suzuki K Poulose <suzuki.poulose@arm.com>
In-Reply-To: <1692681973-20764-10-git-send-email-quic_taozha@quicinc.com>
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On 22/08/2023 06:26, 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.
> 
> Add the nodes to read a set of the edge control value and mask
> of the DSB in TPDM.
> 
> Signed-off-by: Tao Zhang <quic_taozha@quicinc.com>
> ---
>   .../ABI/testing/sysfs-bus-coresight-devices-tpdm   |  51 ++++++
>   drivers/hwtracing/coresight/coresight-tpdm.c       | 177 ++++++++++++++++++++-
>   drivers/hwtracing/coresight/coresight-tpdm.h       |  63 ++++++++
>   3 files changed, 288 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
> index e17d1b4..097fdc4 100644
> --- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
> +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
> @@ -57,3 +57,54 @@ 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

s/6.5/6.7

> +Contact:	Jinlong Mao (QUIC) <quic_jinlmao@quicinc.com>, Tao Zhang (QUIC) <quic_taozha@quicinc.com>
> +Description:
> +		(RW) Set/Get 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

same as above

> +Contact:	Jinlong Mao (QUIC) <quic_jinlmao@quicinc.com>, Tao Zhang (QUIC) <quic_taozha@quicinc.com>
> +Description:
> +		Write a data to control the edge detection corresponding to
> +		the index number. Before writing data to this sysfs file,
> +		"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:
> +		Write a data to mask the edge detection corresponding to the index
> +		number. Before writing data to this sysfs file, "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.
> +
> +What:		/sys/bus/coresight/devices/<tpdm-name>/dsb_edge/edcr[0:15]
> +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 value of the DSB in TPDM.

Read edge control register n for edcr<n>.

> +
> +What:		/sys/bus/coresight/devices/<tpdm-name>/dsb_edge/edcmr[0:7]
> +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 of the DSB in TPDM.
> \ No newline at end of file
> diff --git a/drivers/hwtracing/coresight/coresight-tpdm.c b/drivers/hwtracing/coresight/coresight-tpdm.c
> index 2424eb7..ba61e6a 100644
> --- a/drivers/hwtracing/coresight/coresight-tpdm.c
> +++ b/drivers/hwtracing/coresight/coresight-tpdm.c
> @@ -21,6 +21,29 @@
>   
>   DEFINE_CORESIGHT_DEVLIST(tpdm_devs, "tpdm");
>   
> +/* Read dataset array member with the index number */
> +static ssize_t tpdm_simple_dataset_show(struct device *dev,
> +			   struct device_attribute *attr, char *buf)
> +{
> +	struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
> +	struct tpdm_dataset_attribute *tpdm_attr =
> +		container_of(attr, struct tpdm_dataset_attribute, attr);
> +
> +	if (tpdm_attr->idx >= tpdm_attr->max)

minor nit: See my comment on max below. We could skip max.

> +		return -EINVAL;
> +
> +	switch (tpdm_attr->mem) {
> +	case DSB_EDGE_CTRL:
		if (tmp_attr->idx > TPDM_DSB_MAX_EDCR)
			break;

> +		return sysfs_emit(buf, "0x%x\n",
> +				drvdata->dsb->edge_ctrl[tpdm_attr->idx]);
> +	case DSB_EDGE_CTRL_MASK:
		if (tmp_attr->idx > TPDM_DSB_MAX_EDCMR)
			break;

> +		return sysfs_emit(buf, "0x%x\n",
> +				drvdata->dsb->edge_ctrl_mask[tpdm_attr->idx]);
	}

	return -EINVAL;


> +	default:
> +		return -EINVAL;
> +	}
> +}
> +
>   static bool tpdm_has_dsb_dataset(struct tpdm_drvdata *drvdata)
>   {
>   	return (drvdata->datasets & TPDM_PIDR0_DS_DSB);
> @@ -71,7 +94,14 @@ static void set_dsb_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 */
> @@ -296,6 +326,109 @@ static ssize_t dsb_mode_store(struct device *dev,
>   }
>   static DEVICE_ATTR_RW(dsb_mode);
>   
> +static ssize_t 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 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(ctrl_idx);
> +
> +/*
> + * 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 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, 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);
> +	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_WO(ctrl_val);
> +
> +static ssize_t 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_WO(ctrl_mask);
> +
>   static ssize_t dsb_trig_type_show(struct device *dev,
>   		  struct device_attribute *attr, char *buf)
>   {
> @@ -367,6 +500,37 @@ static ssize_t dsb_trig_ts_store(struct device *dev,
>   }
>   static DEVICE_ATTR_RW(dsb_trig_ts);
>   
> +static struct attribute *tpdm_dsb_edge_attrs[] = {
> +	&dev_attr_ctrl_idx.attr,
> +	&dev_attr_ctrl_val.attr,
> +	&dev_attr_ctrl_mask.attr,
> +	DSB_EDGE_CTRL_ATTR(0),
> +	DSB_EDGE_CTRL_ATTR(1),
> +	DSB_EDGE_CTRL_ATTR(2),
> +	DSB_EDGE_CTRL_ATTR(3),
> +	DSB_EDGE_CTRL_ATTR(4),
> +	DSB_EDGE_CTRL_ATTR(5),
> +	DSB_EDGE_CTRL_ATTR(6),
> +	DSB_EDGE_CTRL_ATTR(7),
> +	DSB_EDGE_CTRL_ATTR(8),
> +	DSB_EDGE_CTRL_ATTR(9),
> +	DSB_EDGE_CTRL_ATTR(10),
> +	DSB_EDGE_CTRL_ATTR(11),
> +	DSB_EDGE_CTRL_ATTR(12),
> +	DSB_EDGE_CTRL_ATTR(13),
> +	DSB_EDGE_CTRL_ATTR(14),
> +	DSB_EDGE_CTRL_ATTR(15),
> +	DSB_EDGE_CTRL_MASK_ATTR(0),
> +	DSB_EDGE_CTRL_MASK_ATTR(1),
> +	DSB_EDGE_CTRL_MASK_ATTR(2),
> +	DSB_EDGE_CTRL_MASK_ATTR(3),
> +	DSB_EDGE_CTRL_MASK_ATTR(4),
> +	DSB_EDGE_CTRL_MASK_ATTR(5),
> +	DSB_EDGE_CTRL_MASK_ATTR(6),
> +	DSB_EDGE_CTRL_MASK_ATTR(7),
> +	NULL,
> +};
> +
>   static struct attribute *tpdm_dsb_attrs[] = {
>   	&dev_attr_dsb_mode.attr,
>   	&dev_attr_dsb_trig_ts.attr,
> @@ -374,14 +538,21 @@ static struct attribute *tpdm_dsb_attrs[] = {
>   	NULL,
>   };
>   
> -static struct attribute_group tpdm_dsb_attr_grp = {
> +static struct attribute_group tpdm_dsb_attrs_grp = {
>   	.attrs = tpdm_dsb_attrs,
>   	.is_visible = tpdm_dsb_is_visible,
>   };
>   
> +static struct attribute_group tpdm_dsb_edge_grp = {
> +	.attrs = tpdm_dsb_edge_attrs,
> +	.is_visible = tpdm_dsb_is_visible,
> +	.name = "dsb_edge",
> +};
> +
>   static const struct attribute_group *tpdm_attr_grps[] = {
>   	&tpdm_attr_grp,
> -	&tpdm_dsb_attr_grp,
> +	&tpdm_dsb_attrs_grp,
> +	&tpdm_dsb_edge_grp,
>   	NULL,
>   };
>   
> diff --git a/drivers/hwtracing/coresight/coresight-tpdm.h b/drivers/hwtracing/coresight/coresight-tpdm.h
> index f57c9fe..9736e00 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)
> @@ -37,6 +39,16 @@
>   /* High performance mode */
>   #define TPDM_DSB_MODE_HPBYTESEL(val)	(val & GENMASK(8, 4))
>   
> +#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)
> @@ -63,14 +75,44 @@
>   #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
> +
> +#define tpdm_simple_dataset_ro(name, mem, idx, max)			\

Do we need max ? The mem itself is enough to help you
choose the max ? See my comment above.

> +	(&((struct tpdm_dataset_attribute[]) {			\
> +	   {								\
> +		__ATTR(name, 0444, tpdm_simple_dataset_show, NULL),	\
> +		mem,							\
> +		idx,							\
> +		max,							\
> +	   }								\
> +	})[0].attr.attr)
> +
> +#define DSB_EDGE_CTRL_ATTR(nr)					\
> +		tpdm_simple_dataset_ro(edcr##nr,		\
> +		DSB_EDGE_CTRL, nr, TPDM_DSB_MAX_EDCR)
> +
> +#define DSB_EDGE_CTRL_MASK_ATTR(nr)				\
> +		tpdm_simple_dataset_ro(edcmr##nr,		\
> +		DSB_EDGE_CTRL_MASK, nr, TPDM_DSB_MAX_EDCMR)
> +
>   /**
>    * struct dsb_dataset - specifics associated to dsb dataset
>    * @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];
>   	bool			trig_ts;
>   	bool			trig_type;
>   };
> @@ -96,4 +138,25 @@ struct tpdm_drvdata {
>   	struct dsb_dataset	*dsb;
>   };
>   
> +/* Enumerate members of various datasets */
> +enum dataset_mem {
> +	DSB_EDGE_CTRL,
> +	DSB_EDGE_CTRL_MASK,
> +};
> +
> +/**
> + * struct tpdm_dataset_attribute - Record the member variables and
> + * index number of datasets that need to be operated by sysfs file
> + * @attr:       The device attribute
> + * @mem:        The member in the dataset data structure
> + * @idx:        The index number of the array data
> + * @max:        The maximal number of the array data

As mentioned above, you could remove this.

Suzuki

> + */
> +struct tpdm_dataset_attribute {
> +	struct device_attribute attr;
> +	enum dataset_mem mem;
> +	u32 idx;
> +	u32 max;
> +};
> +
>   #endif  /* _CORESIGHT_CORESIGHT_TPDM_H */