Received-SPF: pass (google.com: domain of linux-kernel+bounces-3330-linux.lists.archive=gmail.com@vger.kernel.org designates 139.178.88.99 as permitted sender) client-ip=139.178.88.99;
Message-ID: <88e51407-344e-4584-8711-29cc014c782b@arm.com>
Date: Mon, 18 Dec 2023 10:27:43 +0000
Precedence: bulk
MIME-Version: 1.0
User-Agent: Mozilla Thunderbird
Subject: Re: [PATCH v3 2/8] coresight-tpda: Add support to configure CMB
 element
Content-Language: en-GB
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>, Song Chai <quic_songchai@quicinc.com>,
 linux-arm-msm@vger.kernel.org, andersson@kernel.org
References: <1700533494-19276-1-git-send-email-quic_taozha@quicinc.com>
 <1700533494-19276-3-git-send-email-quic_taozha@quicinc.com>
From: Suzuki K Poulose <suzuki.poulose@arm.com>
In-Reply-To: <1700533494-19276-3-git-send-email-quic_taozha@quicinc.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit

On 21/11/2023 02:24, Tao Zhang wrote:
> Read the CMB element size from the device tree. Set the register
> bit that controls the CMB element size of the corresponding port.
> 
> Signed-off-by: Tao Zhang <quic_taozha@quicinc.com>
> Signed-off-by: Mao Jinlong <quic_jinlmao@quicinc.com>
> ---
>   drivers/hwtracing/coresight/coresight-tpda.c | 117 +++++++++++--------
>   drivers/hwtracing/coresight/coresight-tpda.h |   6 +
>   2 files changed, 74 insertions(+), 49 deletions(-)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-tpda.c b/drivers/hwtracing/coresight/coresight-tpda.c
> index 5f82737c37bb..e3762f38abb3 100644
> --- a/drivers/hwtracing/coresight/coresight-tpda.c
> +++ b/drivers/hwtracing/coresight/coresight-tpda.c
> @@ -28,24 +28,54 @@ static bool coresight_device_is_tpdm(struct coresight_device *csdev)
>   			CORESIGHT_DEV_SUBTYPE_SOURCE_TPDM);
>   }
>   
> +static void tpdm_clear_element_size(struct coresight_device *csdev)
> +{
> +	struct tpda_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
> +
> +	if (drvdata->dsb_esize)
> +		drvdata->dsb_esize = 0;
> +	if (drvdata->cmb_esize)
> +		drvdata->cmb_esize = 0;

Why do we need the if (...) check here ?

> +}
> +
> +static void tpda_set_element_size(struct tpda_drvdata *drvdata, u32 *val)
> +{
> +
> +	if (drvdata->dsb_esize == 64)
> +		*val |= TPDA_Pn_CR_DSBSIZE;
> +	else if (drvdata->dsb_esize == 32)
> +		*val &= ~TPDA_Pn_CR_DSBSIZE;
> +
> +	if (drvdata->cmb_esize == 64)
> +		*val |= FIELD_PREP(TPDA_Pn_CR_CMBSIZE, 0x2);
> +	else if (drvdata->cmb_esize == 32)
> +		*val |= FIELD_PREP(TPDA_Pn_CR_CMBSIZE, 0x1);
> +	else if (drvdata->cmb_esize == 8)
> +		*val &= ~TPDA_Pn_CR_CMBSIZE;
> +}
> +


>   /*
> - * Read the DSB element size from the TPDM device
> + * Read the element size from the TPDM device
>    * Returns
> - *    The dsb element size read from the devicetree if available.
> + *    The element size read from the devicetree if available.
>    *    0 - Otherwise, with a warning once.

This doesn't match the function ? It return 0 on success and
error (-EINVAL) on failure ?

>    */
> -static int tpdm_read_dsb_element_size(struct coresight_device *csdev)
> +static int tpdm_read_element_size(struct tpda_drvdata *drvdata,
> +				  struct coresight_device *csdev)
>   {
> -	int rc = 0;
> -	u8 size = 0;
> -
> -	rc = fwnode_property_read_u8(dev_fwnode(csdev->dev.parent),
> -			"qcom,dsb-element-size", &size);
> +	int rc = -EINVAL;
> +
> +	if (!fwnode_property_read_u8(dev_fwnode(csdev->dev.parent),
> +			"qcom,dsb-element-size", &drvdata->dsb_esize))
> +		rc = 0;
> +	if (!fwnode_property_read_u8(dev_fwnode(csdev->dev.parent),
> +			"qcom,cmb-element-size", &drvdata->cmb_esize))
> +		rc = 0;

Are we not silently resetting the error if the former failed ?

Could we not :

	rc |= fwnode_...

	rc |= fwnode_...

instead ?

Also what is the expectation here ? Are these properties a MUST for
TPDM ?

>   	if (rc)
>   		dev_warn_once(&csdev->dev,
> -			"Failed to read TPDM DSB Element size: %d\n", rc);
> +			"Failed to read TPDM Element size: %d\n", rc);
>   
> -	return size;
> +	return rc;
>   }
>   
>   /*
> @@ -56,11 +86,12 @@ static int tpdm_read_dsb_element_size(struct coresight_device *csdev)
>    * Parameter "inport" is used to pass in the input port number
>    * of TPDA, and it is set to -1 in the recursize call.
>    */
> -static int tpda_get_element_size(struct coresight_device *csdev,
> +static int tpda_get_element_size(struct tpda_drvdata *drvdata,
> +				 struct coresight_device *csdev,
>   				 int inport)
>   {
> -	int dsb_size = -ENOENT;
> -	int i, size;
> +	int rc = 0;
> +	int i;
>   	struct coresight_device *in;
>   
>   	for (i = 0; i < csdev->pdata->nr_inconns; i++) {
> @@ -74,25 +105,21 @@ static int tpda_get_element_size(struct coresight_device *csdev,
>   			continue;
>   
>   		if (coresight_device_is_tpdm(in)) {
> -			size = tpdm_read_dsb_element_size(in);
> +			if ((drvdata->dsb_esize) || (drvdata->cmb_esize))
> +				return -EEXIST;
> +			rc = tpdm_read_element_size(drvdata, in);
> +			if (rc)
> +				return rc;
>   		} else {
>   			/* Recurse down the path */
> -			size = tpda_get_element_size(in, -1);
> -		}
> -
> -		if (size < 0)
> -			return size;
> -
> -		if (dsb_size < 0) {
> -			/* Found a size, save it. */
> -			dsb_size = size;
> -		} else {
> -			/* Found duplicate TPDMs */
> -			return -EEXIST;
> +			rc = tpda_get_element_size(drvdata, in, -1);
> +			if (rc)
> +				return rc;
>   		}
>   	}
>   
> -	return dsb_size;
> +
> +	return rc;
>   }
>   
>   /* Settings pre enabling port control register */
> @@ -109,7 +136,7 @@ static void tpda_enable_pre_port(struct tpda_drvdata *drvdata)
>   static int tpda_enable_port(struct tpda_drvdata *drvdata, int port)
>   {
>   	u32 val;
> -	int size;
> +	int rc;
>   
>   	val = readl_relaxed(drvdata->base + TPDA_Pn_CR(port));
>   	/*
> @@ -117,29 +144,21 @@ static int tpda_enable_port(struct tpda_drvdata *drvdata, int port)
>   	 * Set the bit to 0 if the size is 32
>   	 * Set the bit to 1 if the size is 64
>   	 */
> -	size = tpda_get_element_size(drvdata->csdev, port);
> -	switch (size) {
> -	case 32:
> -		val &= ~TPDA_Pn_CR_DSBSIZE;
> -		break;
> -	case 64:
> -		val |= TPDA_Pn_CR_DSBSIZE;
> -		break;
> -	case 0:
> -		return -EEXIST;
> -	case -EEXIST:
> +	tpdm_clear_element_size(drvdata->csdev);
> +	rc = tpda_get_element_size(drvdata, drvdata->csdev, port);
> +	if (!rc && ((drvdata->dsb_esize) || (drvdata->cmb_esize))) {
> +		tpda_set_element_size(drvdata, &val);
> +		/* Enable the port */
> +		val |= TPDA_Pn_CR_ENA;
> +		writel_relaxed(val, drvdata->base + TPDA_Pn_CR(port));
> +	} else if (rc == -EEXIST)
>   		dev_warn_once(&drvdata->csdev->dev,
> -			"Detected multiple TPDMs on port %d", -EEXIST);
> -		return -EEXIST;
> -	default:
> -		return -EINVAL;
> -	}
> -
> -	/* Enable the port */
> -	val |= TPDA_Pn_CR_ENA;
> -	writel_relaxed(val, drvdata->base + TPDA_Pn_CR(port));
> +			      "Detected multiple TPDMs on port %d", -EEXIST);
> +	else
> +		dev_warn_once(&drvdata->csdev->dev,
> +			      "Didn't find TPDM elem size");

"element size"

>   
> -	return 0;
> +	return rc;
>   }
>   
>   static int __tpda_enable(struct tpda_drvdata *drvdata, int port)
> diff --git a/drivers/hwtracing/coresight/coresight-tpda.h b/drivers/hwtracing/coresight/coresight-tpda.h
> index b3b38fd41b64..29164fd9711f 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 CMB data set element size bit */
> +#define TPDA_Pn_CR_CMBSIZE		GENMASK(7, 6)
>   /* Aggregator port DSB data set element size bit */
>   #define TPDA_Pn_CR_DSBSIZE		BIT(8)
>   
> @@ -25,6 +27,8 @@
>    * @csdev:      component vitals needed by the framework.
>    * @spinlock:   lock for the drvdata value.
>    * @enable:     enable status of the component.
> + * @dsb_esize   Record the DSB element size.
> + * @cmb_esize   Record the CMB element size.
>    */
>   struct tpda_drvdata {
>   	void __iomem		*base;
> @@ -32,6 +36,8 @@ struct tpda_drvdata {
>   	struct coresight_device	*csdev;
>   	spinlock_t		spinlock;
>   	u8			atid;
> +	u8			dsb_esize;
> +	u8			cmb_esize;
>   };
>   
>   #endif  /* _CORESIGHT_CORESIGHT_TPDA_H */

Suzuki