Subject: Re: [PATCH v5 08/14] coresight: cti: Enable CTI associated with devices.

From: Mathieu Poirier <[email-masked]>
Date: Mon, 25 Nov 2019 15:45:21 -0700

On Tue, Nov 19, 2019 at 11:19:06PM +0000, Mike Leach wrote:
> The CoreSight subsystem enables a path of devices from source to sink.
> Any CTI devices associated with the path devices must be enabled at the
> same time.
> 
> This patch adds an associated coresight_device element to the main
> coresight device structure, and uses this to create associations between
> the CTI and other devices based on the device tree data. The associated
> device element is used to enable CTI in conjunction with the path elements.
> 
> CTI devices are reference counted so where a single CTI is associated with
> multiple elements on the path, it will be enabled on the first associated
> device enable, and disabled with the last associated device disable.
> 
> Signed-off-by: Mike Leach <[email-masked]>
> ---
>  drivers/hwtracing/coresight/coresight-cti.c   | 87 +++++++++++++++++++
>  .../hwtracing/coresight/coresight-platform.c  | 23 +++++
>  drivers/hwtracing/coresight/coresight-priv.h  |  6 ++
>  drivers/hwtracing/coresight/coresight.c       | 58 +++++++++++--
>  include/linux/coresight.h                     |  5 ++
>  5 files changed, 173 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-cti.c b/drivers/hwtracing/coresight/coresight-cti.c
> index 369488dd7b8e..cf116463149a 100644
> --- a/drivers/hwtracing/coresight/coresight-cti.c
> +++ b/drivers/hwtracing/coresight/coresight-cti.c
> @@ -440,6 +440,90 @@ int cti_channel_setop(struct device *dev, enum cti_chan_set_op op,
>  	return err;
>  }
>  
> +/*
> + * Look for a matching connection device name in the list of
> + * connections. If found then swap in the csdev name and return
> + * found.
> + */
> +static bool
> +cti_match_con_name(struct cti_device *ctidev, const char *node_name,
> +		   const char *csdev_name)
> +{
> +	struct cti_trig_con *trig_con;
> +
> +	list_for_each_entry(trig_con, &ctidev->trig_cons, node) {
> +		if (trig_con->con_dev_name) {
> +			if (!strcmp(node_name, trig_con->con_dev_name)) {
> +				/* match: so swap in csdev name */
> +				kfree(trig_con->con_dev_name);
> +				trig_con->con_dev_name =
> +					kstrdup(csdev_name, GFP_KERNEL);
> +				return true;
> +			}
> +		}
> +	}
> +	return false;
> +}
> +
> +/*
> + * Search the cti list to add an associated CTI into the supplied CS device
> + * This will set the association if CTI declared before the CS device
> + */
> +void cti_add_assoc_to_csdev(struct coresight_device *csdev)
> +{
> +	struct cti_drvdata *ect_item;
> +	struct cti_device *ctidev;
> +	const char *node_name = NULL, *csdev_name;
> +
> +	/* protect the list */
> +	mutex_lock(&ect_mutex);
> +
> +	/* exit if current is an ECT device.*/
> +	if ((csdev->type == CORESIGHT_DEV_TYPE_ECT) || list_empty(&ect_net))
> +		goto cti_add_done;
> +
> +	/* if we didn't find the csdev previously we used the fwnode name */
> +	node_name = coresight_get_fwnode_name(csdev->dev.parent);
> +
> +	if (!node_name)
> +		goto cti_add_done;
> +
> +	/* this is the name we want to use for the association */
> +	csdev_name = dev_name(&csdev->dev);
> +
> +	/* for each CTI in list... */
> +	list_for_each_entry(ect_item, &ect_net, node) {
> +		ctidev = &ect_item->ctidev;
> +		if (cti_match_con_name(ctidev, node_name, csdev_name)) {
> +			/*
> +			 * if we found a matching name then update the
> +			 * association pointers.
> +			 */
> +			csdev->ect_dev = ect_item->csdev;
> +			goto cti_add_done;
> +		}
> +	}
> +cti_add_done:
> +	mutex_unlock(&ect_mutex);
> +}
> +EXPORT_SYMBOL_GPL(cti_add_assoc_to_csdev);
> +
> +/*
> + * Update the cross references where the associated device was found
> + * while we were building the connection info. This will occur if the
> + * assoc device was registered before the CTI.
> + */
> +static void cti_update_conn_xrefs(struct cti_drvdata *drvdata)
> +{
> +	struct cti_trig_con *tc;
> +	struct cti_device *ctidev = &drvdata->ctidev;
> +
> +	list_for_each_entry(tc, &ctidev->trig_cons, node) {
> +		if (tc->con_dev)
> +			tc->con_dev->ect_dev = drvdata->csdev;
> +	}
> +}
> +
>  /** cti ect operations **/
>  int cti_enable(struct coresight_device *csdev)
>  {
> @@ -574,6 +658,9 @@ static int cti_probe(struct amba_device *adev, const struct amba_id *id)
>  	drvdata->csdev_release = drvdata->csdev->dev.release;
>  	drvdata->csdev->dev.release = cti_device_release;
>  
> +	/* set any cross references */
> +	cti_update_conn_xrefs(drvdata);
> +
>  	/* all done - dec pm refcount */
>  	pm_runtime_put(&adev->dev);
>  	dev_info(&drvdata->csdev->dev, "CTI initialized\n");
> diff --git a/drivers/hwtracing/coresight/coresight-platform.c b/drivers/hwtracing/coresight/coresight-platform.c
> index 3c5bee429105..6721cb1af5fe 100644
> --- a/drivers/hwtracing/coresight/coresight-platform.c
> +++ b/drivers/hwtracing/coresight/coresight-platform.c
> @@ -293,6 +293,12 @@ static int of_get_coresight_platform_data(struct device *dev,
>  
>  	return 0;
>  }
> +
> +static inline const char *of_coresight_get_node_name(struct device *dev)
> +{
> +	return dev->of_node->full_name;
> +}
> +
>  #else
>  static inline int
>  of_get_coresight_platform_data(struct device *dev,
> @@ -305,6 +311,11 @@ static inline int of_coresight_get_cpu(struct device *dev)
>  {
>  	return -ENODEV;
>  }
> +
> +static inline const char *of_coresight_get_node_name(struct device *dev)
> +{
> +	return NULL;
> +}
>  #endif
>  
>  #ifdef CONFIG_ACPI
> @@ -766,6 +777,18 @@ static inline int acpi_coresight_get_cpu(struct device *dev)
>  }
>  #endif
>  
> +const char *coresight_get_fwnode_name(struct device *dev)
> +{
> +	const char *node_name = NULL;
> +	struct fwnode_handle *fwnode = dev_fwnode(dev);
> +
> +	if (is_of_node(fwnode))
> +		node_name = of_coresight_get_node_name(dev);
> +
> +	return node_name;
> +}
> +EXPORT_SYMBOL_GPL(coresight_get_fwnode_name);
> +
>  int coresight_get_cpu(struct device *dev)
>  {
>  	if (is_of_node(dev->fwnode))
> diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h
> index aba6b789c969..484e5ec593bb 100644
> --- a/drivers/hwtracing/coresight/coresight-priv.h
> +++ b/drivers/hwtracing/coresight/coresight-priv.h
> @@ -162,6 +162,12 @@ static inline int etm_readl_cp14(u32 off, unsigned int *val) { return 0; }
>  static inline int etm_writel_cp14(u32 off, u32 val) { return 0; }
>  #endif
>  
> +#ifdef CONFIG_CORESIGHT_CTI
> +extern void cti_add_assoc_to_csdev(struct coresight_device *csdev);
> +#else
> +static inline void cti_add_assoc_to_csdev(struct coresight_device *csdev) {}
> +#endif
> +
>  /*
>   * Macros and inline functions to handle CoreSight UCI data and driver
>   * private data in AMBA ID table entries, and extract data values.
> diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c
> index 1a5fdf2710ff..7657be009246 100644
> --- a/drivers/hwtracing/coresight/coresight.c
> +++ b/drivers/hwtracing/coresight/coresight.c
> @@ -216,6 +216,31 @@ void coresight_disclaim_device(void __iomem *base)
>  	CS_LOCK(base);
>  }
>  
> +/* enable or disable an associated CTI device of the supplied CS device */
> +static int
> +coresight_control_assoc_ectdev(struct coresight_device *csdev, bool enable)
> +{
> +	int ect_ret = 0;
> +	struct coresight_device *ect_csdev = csdev->ect_dev;
> +
> +	if (!ect_csdev)
> +		return 0;
> +
> +	if (enable) {
> +		if (ect_ops(ect_csdev)->enable)
> +			ect_ret = ect_ops(ect_csdev)->enable(ect_csdev);
> +	} else {
> +		if (ect_ops(ect_csdev)->disable)
> +			ect_ret = ect_ops(ect_csdev)->disable(ect_csdev);
> +	}
> +
> +	/* output warning if ECT enable is preventing trace operation */
> +	if (ect_ret)
> +		dev_info(&csdev->dev, "Associated ECT device (%s) %s failed\n",
> +		 dev_name(&ect_csdev->dev), enable ? "enable" : "disable");

Indentation problem - please replace with:

                dev_info(&csdev->dev, "Associated ECT device (%s) %s failed\n",
                         dev_name(&ect_csdev->dev),
                         enable ? "enable" : "disable");

> +	return ect_ret;
> +}
> +
>  static int coresight_enable_sink(struct coresight_device *csdev,
>  				 u32 mode, void *data)
>  {
> @@ -228,11 +253,15 @@ static int coresight_enable_sink(struct coresight_device *csdev,
>  	if (!sink_ops(csdev)->enable)
>  		return -EINVAL;
>  
> -	ret = sink_ops(csdev)->enable(csdev, mode, data);
> +	ret = coresight_control_assoc_ectdev(csdev, true);
>  	if (ret)
>  		return ret;
> +	ret = sink_ops(csdev)->enable(csdev, mode, data);
> +	if (ret) {
> +		coresight_control_assoc_ectdev(csdev, false);
> +		return ret;
> +	}
>  	csdev->enable = true;
> -

Unneeded modification.

With the above changes:
Reviewed-by: Mathieu Poirier <[email-masked]>

>  	return 0;
>  }
>  
> @@ -246,6 +275,7 @@ static void coresight_disable_sink(struct coresight_device *csdev)
>  	ret = sink_ops(csdev)->disable(csdev);
>  	if (ret)
>  		return;
> +	coresight_control_assoc_ectdev(csdev, false);
>  	csdev->enable = false;
>  }
>  
> @@ -269,8 +299,15 @@ static int coresight_enable_link(struct coresight_device *csdev,
>  	if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_SPLIT && outport < 0)
>  		return outport;
>  
> -	if (link_ops(csdev)->enable)
> -		ret = link_ops(csdev)->enable(csdev, inport, outport);
> +	if (link_ops(csdev)->enable) {
> +		ret = coresight_control_assoc_ectdev(csdev, true);
> +		if (!ret) {
> +			ret = link_ops(csdev)->enable(csdev, inport, outport);
> +			if (ret)
> +				coresight_control_assoc_ectdev(csdev, false);
> +		}
> +	}
> +
>  	if (!ret)
>  		csdev->enable = true;
>  
> @@ -300,8 +337,10 @@ static void coresight_disable_link(struct coresight_device *csdev,
>  		nr_conns = 1;
>  	}
>  
> -	if (link_ops(csdev)->disable)
> +	if (link_ops(csdev)->disable) {
>  		link_ops(csdev)->disable(csdev, inport, outport);
> +		coresight_control_assoc_ectdev(csdev, false);
> +	}
>  
>  	for (i = 0; i < nr_conns; i++)
>  		if (atomic_read(&csdev->refcnt[i]) != 0)
> @@ -322,9 +361,14 @@ static int coresight_enable_source(struct coresight_device *csdev, u32 mode)
>  
>  	if (!csdev->enable) {
>  		if (source_ops(csdev)->enable) {
> -			ret = source_ops(csdev)->enable(csdev, NULL, mode);
> +			ret = coresight_control_assoc_ectdev(csdev, true);
>  			if (ret)
>  				return ret;
> +			ret = source_ops(csdev)->enable(csdev, NULL, mode);
> +			if (ret) {
> +				coresight_control_assoc_ectdev(csdev, false);
> +				return ret;
> +			};
>  		}
>  		csdev->enable = true;
>  	}
> @@ -347,6 +391,7 @@ static bool coresight_disable_source(struct coresight_device *csdev)
>  	if (atomic_dec_return(csdev->refcnt) == 0) {
>  		if (source_ops(csdev)->disable)
>  			source_ops(csdev)->disable(csdev, NULL);
> +		coresight_control_assoc_ectdev(csdev, false);
>  		csdev->enable = false;
>  	}
>  	return !csdev->enable;
> @@ -1252,6 +1297,7 @@ struct coresight_device *coresight_register(struct coresight_desc *desc)
>  
>  	coresight_fixup_device_conns(csdev);
>  	coresight_fixup_orphan_conns(csdev);
> +	cti_add_assoc_to_csdev(csdev);
>  
>  	mutex_unlock(&coresight_mutex);
>  
> diff --git a/include/linux/coresight.h b/include/linux/coresight.h
> index b3e582d96a34..b5dc9baf0c58 100644
> --- a/include/linux/coresight.h
> +++ b/include/linux/coresight.h
> @@ -163,6 +163,8 @@ struct coresight_connection {
>   *		activated but not yet enabled.  Enabling for a _sink_
>   *		appens when a source has been selected for that it.
>   * @ea:		Device attribute for sink representation under PMU directory.
> + * @ect_dev:	Associated cross trigger device. Not part of the trace data
> + *		path or connections.
>   */
>  struct coresight_device {
>  	struct coresight_platform_data *pdata;
> @@ -176,6 +178,8 @@ struct coresight_device {
>  	/* sink specific fields */
>  	bool activated;	/* true only if a sink is part of a path */
>  	struct dev_ext_attribute *ea;
> +	/* cross trigger handling */
> +	struct coresight_device *ect_dev;
>  };
>  
>  /*
> @@ -341,5 +345,6 @@ static inline bool coresight_loses_context_with_cpu(struct device *dev)
>  extern int coresight_get_cpu(struct device *dev);
>  
>  struct coresight_platform_data *coresight_get_platform_data(struct device *dev);
> +extern const char *coresight_get_fwnode_name(struct device *dev);
>  
>  #endif
> -- 
> 2.17.1
> 

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