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Message-ID: <444bc278-a3e3-7d99-6020-7c3337371f66@arm.com>
Date:   Tue, 23 May 2023 11:07:01 +0100
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Subject: Re: [PATCH v4 02/11] coresight-tpda: Add DSB dataset support
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: <1682586037-25973-1-git-send-email-quic_taozha@quicinc.com>
 <1682586037-25973-3-git-send-email-quic_taozha@quicinc.com>
From:   Suzuki K Poulose <suzuki.poulose@arm.com>
In-Reply-To: <1682586037-25973-3-git-send-email-quic_taozha@quicinc.com>
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On 27/04/2023 10:00, 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-core.c |  1 +
>   drivers/hwtracing/coresight/coresight-tpda.c | 92 +++++++++++++++++++++++++---
>   drivers/hwtracing/coresight/coresight-tpda.h |  4 ++
>   drivers/hwtracing/coresight/coresight-tpdm.c |  2 +-
>   include/linux/coresight.h                    |  1 +
>   5 files changed, 90 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
> index 2af416b..f1eacbb 100644
> --- a/drivers/hwtracing/coresight/coresight-core.c
> +++ b/drivers/hwtracing/coresight/coresight-core.c
> @@ -1092,6 +1092,7 @@ static int coresight_validate_source(struct coresight_device *csdev,
>   
>   	if (subtype != CORESIGHT_DEV_SUBTYPE_SOURCE_PROC &&
>   	    subtype != CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE &&
> +		subtype != CORESIGHT_DEV_SUBTYPE_SOURCE_TPDM &&
>   	    subtype != CORESIGHT_DEV_SUBTYPE_SOURCE_OTHERS) {
>   		dev_err(&csdev->dev, "wrong device subtype in %s\n", function);
>   		return -EINVAL;

Please see the comment at the bottom.

> diff --git a/drivers/hwtracing/coresight/coresight-tpda.c b/drivers/hwtracing/coresight/coresight-tpda.c
> index 8d2b9d2..af9c72f 100644
> --- a/drivers/hwtracing/coresight/coresight-tpda.c
> +++ b/drivers/hwtracing/coresight/coresight-tpda.c
> @@ -21,6 +21,56 @@
>   
>   DEFINE_CORESIGHT_DEVLIST(tpda_devs, "tpda");
>   
> +/* Search and read element data size from the TPDM node in
> + * 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.
> + */
> +static int tpda_set_element_size(struct tpda_drvdata *drvdata,
> +			   struct coresight_device *csdev, int inport, bool parent)
> +{
> +	static int nr_inport;
> +	int i;
> +	static bool tpdm_found;
> +	struct coresight_device *in_csdev;
> +
> +	if (inport > (TPDA_MAX_INPORTS - 1))
> +		return -EINVAL;
> +
> +	if (parent) {
> +		nr_inport = inport;
> +		tpdm_found = false;
> +	}
> +
> +	for (i = 0; i < csdev->pdata->nr_inconns; i++) {
> +		in_csdev = csdev->pdata->in_conns[i]->src_dev;
> +		if (!in_csdev)
> +			break;
> +
> +		if (parent)
> +			if (csdev->pdata->in_conns[i]->dest_port != inport)
> +				continue;
> +
> +		if (in_csdev->subtype.source_subtype

We must match the in_csdev->type to be SOURCE && the 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);

When we know, we have found a source device, we don't need to recurse
down and could simply 'continue' to the next one in the list and skip
the call below.

> +		}
> +		tpda_set_element_size(drvdata, in_csdev, 0, false);
> +	}
> +
> +	return 0;
> +}
> +
>   /* Settings pre enabling port control register */
>   static void tpda_enable_pre_port(struct tpda_drvdata *drvdata)
>   {
> @@ -32,26 +82,43 @@ 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;
> +	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 +126,23 @@ 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);
> +	if (ret)
> +		return ret;
>   
>   	spin_lock(&drvdata->spinlock);
> -	if (atomic_read(&in->dest_refcnt) == 0)
> +	if (atomic_read(&in->dest_refcnt) == 0) {
>   		__tpda_enable(drvdata, in->dest_port);

ret = ... ?

> +		if (!ret) {


> +			atomic_inc(&in->dest_refcnt);
> +			dev_dbg(drvdata->dev, "TPDA inport %d enabled.\n", in->dest_port);
> +		}
> +	}

>   
> -	atomic_inc(&in->dest_refcnt);

This seems wrong, as we may fail to hold additional refcounts for the
additional sessions ?

>   	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..7332e9c 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, it must be 32 or 64.

minor nit:

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 */
> diff --git a/drivers/hwtracing/coresight/coresight-tpdm.c b/drivers/hwtracing/coresight/coresight-tpdm.c
> index f4854af..ba1867f 100644
> --- a/drivers/hwtracing/coresight/coresight-tpdm.c
> +++ b/drivers/hwtracing/coresight/coresight-tpdm.c
> @@ -205,7 +205,7 @@ static int tpdm_probe(struct amba_device *adev, const struct amba_id *id)
>   	if (!desc.name)
>   		return -ENOMEM;
>   	desc.type = CORESIGHT_DEV_TYPE_SOURCE;
> -	desc.subtype.source_subtype = CORESIGHT_DEV_SUBTYPE_SOURCE_OTHERS;
> +	desc.subtype.source_subtype = CORESIGHT_DEV_SUBTYPE_SOURCE_TPDM;
>   	desc.ops = &tpdm_cs_ops;
>   	desc.pdata = adev->dev.platform_data;
>   	desc.dev = &adev->dev;

Please could you split this change, i.e., introduction of
SUBTYPE_SOURCE_TPDM and using this in TPDM driver,
  in a separate patch before this change.

> diff --git a/include/linux/coresight.h b/include/linux/coresight.h
> index 225a5fa..6563896 100644
> --- a/include/linux/coresight.h
> +++ b/include/linux/coresight.h
> @@ -60,6 +60,7 @@ enum coresight_dev_subtype_source {
>   	CORESIGHT_DEV_SUBTYPE_SOURCE_PROC,
>   	CORESIGHT_DEV_SUBTYPE_SOURCE_BUS,
>   	CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE,
> +	CORESIGHT_DEV_SUBTYPE_SOURCE_TPDM,
>   	CORESIGHT_DEV_SUBTYPE_SOURCE_OTHERS,
>   };
>