Subject: Re: [PATCH v9 08/15] coresight: cti: Enable CTI associated with devices.

From: Mathieu Poirier <[email-masked]>
Date: Mon, 17 Feb 2020 16:12:28 -0700

Hi Suzuki,

As far as I can tell Mike made the modifications you have requested.  Please
have a look to make sure it is the case before I add this to my next tree.

Thanks,
Mathieu

On Mon, Feb 10, 2020 at 09:39:17PM +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]>
> Reviewed-by: Mathieu Poirier <[email-masked]>
> ---
>  drivers/hwtracing/coresight/coresight-cti.c  | 129 +++++++++++++++++++
>  drivers/hwtracing/coresight/coresight-cti.h  |   1 +
>  drivers/hwtracing/coresight/coresight-priv.h |  12 ++
>  drivers/hwtracing/coresight/coresight.c      |  71 +++++++++-
>  include/linux/coresight.h                    |   4 +
>  5 files changed, 212 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-cti.c b/drivers/hwtracing/coresight/coresight-cti.c
> index 77c2af247917..c4494923d030 100644
> --- a/drivers/hwtracing/coresight/coresight-cti.c
> +++ b/drivers/hwtracing/coresight/coresight-cti.c
> @@ -4,6 +4,7 @@
>   * Author: Mike Leach <[email-masked]>
>   */
>  
> +#include <linux/property.h>
>  #include "coresight-cti.h"
>  
>  /**
> @@ -440,6 +441,131 @@ 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, set trig con association pointer
> + * and return found.
> + */
> +static bool
> +cti_match_fixup_csdev(struct cti_device *ctidev, const char *node_name,
> +		      struct coresight_device *csdev)
> +{
> +	struct cti_trig_con *tc;
> +	const char *csdev_name;
> +
> +	list_for_each_entry(tc, &ctidev->trig_cons, node) {
> +		if (tc->con_dev_name) {
> +			if (!strcmp(node_name, tc->con_dev_name)) {
> +				/* match: so swap in csdev name & dev */
> +				csdev_name = dev_name(&csdev->dev);
> +				tc->con_dev_name =
> +					devm_kstrdup(&csdev->dev, csdev_name,
> +						     GFP_KERNEL);
> +				tc->con_dev = csdev;
> +				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.
> + * (called from coresight_register() with coresight_mutex locked).
> + */
> +void cti_add_assoc_to_csdev(struct coresight_device *csdev)
> +{
> +	struct cti_drvdata *ect_item;
> +	struct cti_device *ctidev;
> +	const char *node_name = NULL;
> +
> +	/* 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 = cti_plat_get_node_name(dev_fwnode(csdev->dev.parent));
> +	if (!node_name)
> +		goto cti_add_done;
> +
> +	/* for each CTI in list... */
> +	list_for_each_entry(ect_item, &ect_net, node) {
> +		ctidev = &ect_item->ctidev;
> +		if (cti_match_fixup_csdev(ctidev, node_name, csdev)) {
> +			/*
> +			 * if we found a matching csdev then update the ECT
> +			 * association pointer for the device with this CTI.
> +			 */
> +			csdev->ect_dev = ect_item->csdev;
> +			break;
> +		}
> +	}
> +cti_add_done:
> +	mutex_unlock(&ect_mutex);
> +}
> +EXPORT_SYMBOL_GPL(cti_add_assoc_to_csdev);
> +
> +/*
> + * Removing the associated devices is easier.
> + * A CTI will not have a value for csdev->ect_dev.
> + */
> +void cti_remove_assoc_from_csdev(struct coresight_device *csdev)
> +{
> +	struct cti_drvdata *ctidrv;
> +	struct cti_trig_con *tc;
> +	struct cti_device *ctidev;
> +
> +	mutex_lock(&ect_mutex);
> +	if (csdev->ect_dev) {
> +		ctidrv = csdev_to_cti_drvdata(csdev->ect_dev);
> +		ctidev = &ctidrv->ctidev;
> +		list_for_each_entry(tc, &ctidev->trig_cons, node) {
> +			if (tc->con_dev == csdev->ect_dev) {
> +				tc->con_dev = NULL;
> +				break;
> +			}
> +		}
> +		csdev->ect_dev = NULL;
> +	}
> +	mutex_unlock(&ect_mutex);
> +}
> +EXPORT_SYMBOL_GPL(cti_remove_assoc_from_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)
> +			/* set tc->con_dev->ect_dev */
> +			coresight_set_assoc_ectdev_mutex(tc->con_dev,
> +							 drvdata->csdev);
> +	}
> +}
> +
> +static void cti_remove_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) {
> +			coresight_set_assoc_ectdev_mutex(tc->con_dev,
> +							 NULL);
> +		}
> +	}
> +}
> +
>  /** cti ect operations **/
>  int cti_enable(struct coresight_device *csdev)
>  {
> @@ -474,6 +600,7 @@ static void cti_device_release(struct device *dev)
>  	struct cti_drvdata *ect_item, *ect_tmp;
>  
>  	mutex_lock(&ect_mutex);
> +	cti_remove_conn_xrefs(drvdata);
>  
>  	/* remove from the list */
>  	list_for_each_entry_safe(ect_item, ect_tmp, &ect_net, node) {
> @@ -565,6 +692,8 @@ static int cti_probe(struct amba_device *adev, const struct amba_id *id)
>  	/* add to list of CTI devices */
>  	mutex_lock(&ect_mutex);
>  	list_add(&drvdata->node, &ect_net);
> +	/* set any cross references */
> +	cti_update_conn_xrefs(drvdata);
>  	mutex_unlock(&ect_mutex);
>  
>  	/* set up release chain */
> diff --git a/drivers/hwtracing/coresight/coresight-cti.h b/drivers/hwtracing/coresight/coresight-cti.h
> index 469a06a1bb78..578d7e9ac67e 100644
> --- a/drivers/hwtracing/coresight/coresight-cti.h
> +++ b/drivers/hwtracing/coresight/coresight-cti.h
> @@ -216,6 +216,7 @@ int cti_channel_setop(struct device *dev, enum cti_chan_set_op op,
>  		      u32 channel_idx);
>  struct coresight_platform_data *
>  coresight_cti_get_platform_data(struct device *dev);
> +const char *cti_plat_get_node_name(struct fwnode_handle *fwnode);
>  
>  /* cti powered and enabled */
>  static inline bool cti_active(struct cti_config *cfg)
> diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h
> index 357ffef7b825..890f9a5c97c6 100644
> --- a/drivers/hwtracing/coresight/coresight-priv.h
> +++ b/drivers/hwtracing/coresight/coresight-priv.h
> @@ -162,6 +162,16 @@ 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);
> +extern void cti_remove_assoc_from_csdev(struct coresight_device *csdev);
> +
> +#else
> +static inline void cti_add_assoc_to_csdev(struct coresight_device *csdev) {}
> +static inline void
> +cti_remove_assoc_from_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.
> @@ -204,5 +214,7 @@ static inline void *coresight_get_uci_data(const struct amba_id *id)
>  void coresight_release_platform_data(struct coresight_platform_data *pdata);
>  struct coresight_device *
>  coresight_find_csdev_by_fwnode(struct fwnode_handle *r_fwnode);
> +void coresight_set_assoc_ectdev_mutex(struct coresight_device *csdev,
> +				      struct coresight_device *ect_csdev);
>  
>  #endif
> diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c
> index 39a5d9f7a395..c71553c09f8e 100644
> --- a/drivers/hwtracing/coresight/coresight.c
> +++ b/drivers/hwtracing/coresight/coresight.c
> @@ -216,6 +216,44 @@ 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");
> +	return ect_ret;
> +}
> +
> +/*
> + * Set the associated ect / cti device while holding the coresight_mutex
> + * to avoid a race with coresight_enable that may try to use this value.
> + */
> +void coresight_set_assoc_ectdev_mutex(struct coresight_device *csdev,
> +				      struct coresight_device *ect_csdev)
> +{
> +	mutex_lock(&coresight_mutex);
> +	csdev->ect_dev = ect_csdev;
> +	mutex_unlock(&coresight_mutex);
> +}
> +
>  static int coresight_enable_sink(struct coresight_device *csdev,
>  				 u32 mode, void *data)
>  {
> @@ -228,9 +266,14 @@ 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;
>  
>  	return 0;
> @@ -246,6 +289,7 @@ 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 +313,15 @@ 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 +351,10 @@ 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 +375,14 @@ 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 +405,7 @@ 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;
> @@ -964,6 +1023,7 @@ static void coresight_device_release(struct device *dev)
>  {
>  	struct coresight_device *csdev = to_coresight_device(dev);
>  
> +	cti_remove_assoc_from_csdev(csdev);
>  	fwnode_handle_put(csdev->dev.fwnode);
>  	kfree(csdev->refcnt);
>  	kfree(csdev);
> @@ -1246,6 +1306,7 @@ 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..193cc9dbf448 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;
>  };
>  
>  /*
> -- 
> 2.17.1
> 

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