Re: [PATCH v8 08/15] coresight: cti: Enable CTI associated with devices.

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On 13/01/2020 21:31, 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 <mike.leach@xxxxxxxxxx>
Reviewed-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
---
  drivers/hwtracing/coresight/coresight-cti.c   | 129 ++++++++++++++++++
  drivers/hwtracing/coresight/coresight-cti.h   |   1 +
  .../hwtracing/coresight/coresight-platform.c  |   1 +
  drivers/hwtracing/coresight/coresight-priv.h  |  12 ++
  drivers/hwtracing/coresight/coresight.c       |  71 +++++++++-
  include/linux/coresight.h                     |   4 +
  6 files changed, 213 insertions(+), 5 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-cti.c b/drivers/hwtracing/coresight/coresight-cti.c
index 77c2af247917..2be1b310e854 100644
--- a/drivers/hwtracing/coresight/coresight-cti.c
+++ b/drivers/hwtracing/coresight/coresight-cti.c
@@ -4,6 +4,7 @@
   * Author: Mike Leach <mike.leach@xxxxxxxxxx>
   */
+#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 *trig_con;

super minor nit: Please use "struct cti_trig_con *tc;" consistent with
the naming everywhere else. Helps a lot in reading the code, especially
which has a lot of different structures.

+	const char *csdev_name;
+
+	list_for_each_entry(trig_con, &ctidev->trig_cons, node) {
+		if (trig_con->con_dev_name) {

This was allocated via devm_* and ...

+			if (!strcmp(node_name, trig_con->con_dev_name)) {
+				/* match: so swap in csdev name & dev */
+				kfree(trig_con->con_dev_name);

... we free it here using kfree() without devm_ being aware. This could
cause double-free when the device is removed. This should either be
devm_kfree() or simply overwritten with the new string and leave
the device cleanup to free it.

+				csdev_name = dev_name(&csdev->dev);
+				trig_con->con_dev_name =
+					kstrdup(csdev_name, GFP_KERNEL);

Please use devm_kstrdup() here on the CTI device to have a consistent
allocation.


+				trig_con->con_dev = csdev;
+				return true;
+			}
+		}
+	}
+	return false;
+}



+/*
+ * 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;

Should we clear/free the name too ?

+				break;
+			}
+		}
+		csdev->ect_dev = NULL;
+	}
+	mutex_unlock(&ect_mutex);
+}
+EXPORT_SYMBOL_GPL(cti_remove_assoc_from_csdev);
+

...

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-platform.c b/drivers/hwtracing/coresight/coresight-platform.c
index 43418a2126ff..421d4fc95f41 100644
--- a/drivers/hwtracing/coresight/coresight-platform.c
+++ b/drivers/hwtracing/coresight/coresight-platform.c
@@ -313,6 +313,7 @@ static int of_get_coresight_platform_data(struct device *dev,
return 0;
  }
+

nit : spurious hunk ?

  #else
  static inline int
  of_get_coresight_platform_data(struct device *dev,

Otherwise looks good to me

Suzuki



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