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Message-ID: <94b9ae0f-b6ed-1d72-f86a-d33842527681@arm.com>
Date:   Fri, 4 Aug 2023 16:02:05 +0100
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Subject: Re: [PATCH v7 04/13] coresight-tpda: Add DSB dataset support
Content-Language: en-US
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: <1690269353-10829-1-git-send-email-quic_taozha@quicinc.com>
 <1690269353-10829-5-git-send-email-quic_taozha@quicinc.com>
From:   Suzuki K Poulose <suzuki.poulose@arm.com>
In-Reply-To: <1690269353-10829-5-git-send-email-quic_taozha@quicinc.com>
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On 25/07/2023 08:15, Tao Zhang wrote:
> Read the DSB element size from the device tree. Set the register
> bit that controls the DSB element size of the corresponding port.
> 
> Signed-off-by: Tao Zhang <quic_taozha@quicinc.com>
> ---
>   drivers/hwtracing/coresight/coresight-tpda.c | 96 +++++++++++++++++++++++++---
>   drivers/hwtracing/coresight/coresight-tpda.h |  4 ++
>   2 files changed, 90 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-tpda.c b/drivers/hwtracing/coresight/coresight-tpda.c
> index 8d2b9d2..7c71342 100644
> --- a/drivers/hwtracing/coresight/coresight-tpda.c
> +++ b/drivers/hwtracing/coresight/coresight-tpda.c
> @@ -21,6 +21,58 @@
>   
>   DEFINE_CORESIGHT_DEVLIST(tpda_devs, "tpda");
>   
> +/* Search and read element data size from the TPDM node in

minor nit:

/*
  * Search ...

> + * the devicetree. Each input port of TPDA is connected to
> + * a TPDM. Different TPDM supports different types of dataset,
> + * and some may support more than one type of dataset.
> + * Parameter "inport" is used to pass in the input port number
> + * of TPDA, and it is set to 0 in the recursize call.

> + * Parameter "parent" is used to pass in the original call.

Please remove references to the past and describe "match_inport"

> + */
> +static int tpda_set_element_size(struct tpda_drvdata *drvdata,
> +			   struct coresight_device *csdev, int inport, bool match_inport)

May be we could switch the order of the parameters:

match_inport, int port

Or even inport < 0, implies, port wont be matched.

i.e.,

tpda_set_element_size(drvdata, child, inport)

> +{
> +	static int nr_inport;
> +	int i;
> +	static bool tpdm_found;
> +	struct coresight_device *in_csdev;
> +
> +	if (inport > (TPDA_MAX_INPORTS - 1))
> +		return -EINVAL;
> +
> +	if (match_inport) {
> +		nr_inport = inport;
> +		tpdm_found = false;
> +	}

Could we not avoid the static variables and this dance by making the 
function return the dsb_size ? See further down.


> +
> +	for (i = 0; i < csdev->pdata->nr_inconns; i++) {
> +		in_csdev = csdev->pdata->in_conns[i]->src_dev;
> +		if (!in_csdev)
> +			break;
		continue ?
> +
> +		if (match_inport)
> +			if (csdev->pdata->in_conns[i]->dest_port != inport)
> +				continue;
> +
> +		if ((in_csdev->type == CORESIGHT_DEV_TYPE_SOURCE) &&
> +				(in_csdev->subtype.source_subtype
> +				== CORESIGHT_DEV_SUBTYPE_SOURCE_TPDM)) {

Please provide a helper :

static bool coresight_device_is_tpdm(csdev) {
	return
	 (csdev->type == CORESIGHT_DEV_TYPE_SOURCE) &&
	 (in_csdev->subtype.source_subtype ==
		CORESIGHT_DEV_SUBTYPE_SOURCE_TPDM);
}


> +			of_property_read_u8(in_csdev->dev.parent->of_node,
> +					"qcom,dsb-element-size", &drvdata->dsb_esize[nr_inport]);


> +			if (!tpdm_found)
> +				tpdm_found = true;
> +			else
> +				dev_warn(drvdata->dev,
> +					"More than one TPDM is mapped to the TPDA input port %d.\n",
> +					nr_inport);
> +			continue;
> +		}
> +		tpda_set_element_size(drvdata, in_csdev, 0, false);
> +	}
> +

/*
  * Read the DSB element size from the TPDM device
  * Returns
  *	the size read from the firmware if available.
  *	0 - Otherwise, with a Warning once.
  */
static int tpdm_read_dsb_element_size(struct coresight_device *csdev)
{
	int rc, size = 0;

	rc = fwnode_property_read_u8(dev_fwnode(csdev->dev.parent),
				     "qcom,dsb-element-size", &size);
	if (rc)
		dev_warn_once(&in->dev, "Failed to read TPDM DSB Element size: %d\n",
		rc);
	return size;
}

static int tpda_get_element_size(struct coresight_device *csdev,
				 int inport)
{
	int dsb_size = -ENOENT;

	for (i = 0; i < csdev->pdata->nr_inconns; i++) {
		in = csdev->pdata->in_conns[i]->src_dev;
		if (!in)
			continue;
		if (coresight_device_is_tpdm(in)) {
			/* Ignore the TPDMs that do not match port */
			if (inport > 0 &&
			    (csdev->pdata->in_conns[i]->dest_port !=
			    inport))
				continue;
			size = tpdm_read_dsb_element_size(csdev);
		} else {
			/* Recurse down the path */
			size = tpda_set_element_size(in, -1);
		}

		if (size < 0)
			return size;
		/* We have found a size, save it. */
		if (dsb_size < 0) {
			dsb_size = size;
		} else {
			/* We have duplicate TPDMs */
			return -EEXIST;
		}
	}
	return dsb_size;
}


> +	return 0;
> +}
> +
>   /* Settings pre enabling port control register */
>   static void tpda_enable_pre_port(struct tpda_drvdata *drvdata)
>   {
> @@ -32,26 +84,43 @@ static void tpda_enable_pre_port(struct tpda_drvdata *drvdata)
>   	writel_relaxed(val, drvdata->base + TPDA_CR);
>   }
>   
> -static void tpda_enable_port(struct tpda_drvdata *drvdata, int port)
> +static int tpda_enable_port(struct tpda_drvdata *drvdata, int port)
>   {
>   	u32 val;
>   
>   	val = readl_relaxed(drvdata->base + TPDA_Pn_CR(port));
> +	/*
> +	 * Configure aggregator port n DSB data set element size
> +	 * Set the bit to 0 if the size is 32
> +	 * Set the bit to 1 if the size is 64
> +	 */
> +	if (drvdata->dsb_esize[port] == 32)
> +		val &= ~TPDA_Pn_CR_DSBSIZE;
> +	else if (drvdata->dsb_esize[port] == 64)
> +		val |= TPDA_Pn_CR_DSBSIZE;

Couldn't this be detected via tpda_get_element_size()? see below.

> +	else
> +		return -EINVAL;
> +
>   	/* Enable the port */
>   	val |= TPDA_Pn_CR_ENA;
>   	writel_relaxed(val, drvdata->base + TPDA_Pn_CR(port));
> +
> +	return 0;
>   }
>   
> -static void __tpda_enable(struct tpda_drvdata *drvdata, int port)
> +static int __tpda_enable(struct tpda_drvdata *drvdata, int port)
>   {
> +	int ret;
> +
>   	CS_UNLOCK(drvdata->base);
>   
>   	if (!drvdata->csdev->enable)
>   		tpda_enable_pre_port(drvdata);
>   
> -	tpda_enable_port(drvdata, port);
> -
> +	ret = tpda_enable_port(drvdata, port);
>   	CS_LOCK(drvdata->base);
> +
> +	return ret;
>   }
>   
>   static int tpda_enable(struct coresight_device *csdev,
> @@ -59,16 +128,23 @@ static int tpda_enable(struct coresight_device *csdev,
>   		       struct coresight_connection *out)
>   {
>   	struct tpda_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
> +	int ret;
> +
> +	ret = tpda_set_element_size(drvdata, csdev, in->dest_port, true);

	size  = tpda_get_element_size(csdev, in->dest_port);
	switch (size) {
	case 32:
	case 64:
		break;
	case -EEXIST:
		dev_warn_once("Detected multiple TPDMs on port %d", ..)
		fallthrough;
	default:
		return size;
	}

	drvdata->dsb_esize[in->dest_port] = size;

Suzuki


> +	if (ret)
> +		return ret;
>   
>   	spin_lock(&drvdata->spinlock);
> -	if (atomic_read(&in->dest_refcnt) == 0)
> -		__tpda_enable(drvdata, in->dest_port);
> +	if (atomic_read(&in->dest_refcnt) == 0) {
> +		ret = __tpda_enable(drvdata, in->dest_port);
> +		if (!ret) {
> +			atomic_inc(&in->dest_refcnt);
> +			dev_dbg(drvdata->dev, "TPDA inport %d enabled.\n", in->dest_port);
> +		}
> +	}
>   
> -	atomic_inc(&in->dest_refcnt);
>   	spin_unlock(&drvdata->spinlock);
> -
> -	dev_dbg(drvdata->dev, "TPDA inport %d enabled.\n", in->dest_port);
> -	return 0;
> +	return ret;
>   }
>   
>   static void __tpda_disable(struct tpda_drvdata *drvdata, int port)
> diff --git a/drivers/hwtracing/coresight/coresight-tpda.h b/drivers/hwtracing/coresight/coresight-tpda.h
> index 0399678..12a1472 100644
> --- a/drivers/hwtracing/coresight/coresight-tpda.h
> +++ b/drivers/hwtracing/coresight/coresight-tpda.h
> @@ -10,6 +10,8 @@
>   #define TPDA_Pn_CR(n)		(0x004 + (n * 4))
>   /* Aggregator port enable bit */
>   #define TPDA_Pn_CR_ENA		BIT(0)
> +/* Aggregator port DSB data set element size bit */
> +#define TPDA_Pn_CR_DSBSIZE		BIT(8)
>   
>   #define TPDA_MAX_INPORTS	32
>   
> @@ -23,6 +25,7 @@
>    * @csdev:      component vitals needed by the framework.
>    * @spinlock:   lock for the drvdata value.
>    * @enable:     enable status of the component.
> + * @dsb_esize:  DSB element size for each inport, it must be 32 or 64.
>    */
>   struct tpda_drvdata {
>   	void __iomem		*base;
> @@ -30,6 +33,7 @@ struct tpda_drvdata {
>   	struct coresight_device	*csdev;
>   	spinlock_t		spinlock;
>   	u8			atid;
> +	u8			dsb_esize[TPDA_MAX_INPORTS];
>   };
>   
>   #endif  /* _CORESIGHT_CORESIGHT_TPDA_H */