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Subject[PATCH v3 2/7] coresight: perf: Add "sinks" group to PMU directory
Date
Add a "sinks" directory entry so that users can see all the sinks
available in the system in a single place. Individual sink are added
as they are registered with the coresight bus.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
.../hwtracing/coresight/coresight-etm-perf.c | 82 +++++++++++++++++++
.../hwtracing/coresight/coresight-etm-perf.h | 6 +-
drivers/hwtracing/coresight/coresight.c | 18 ++++
include/linux/coresight.h | 7 +-
4 files changed, 110 insertions(+), 3 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c
index f21eb28b6782..cdbdb28dc175 100644
--- a/drivers/hwtracing/coresight/coresight-etm-perf.c
+++ b/drivers/hwtracing/coresight/coresight-etm-perf.c
@@ -14,6 +14,7 @@
#include <linux/perf_event.h>
#include <linux/percpu-defs.h>
#include <linux/slab.h>
+#include <linux/stringhash.h>
#include <linux/types.h>
#include <linux/workqueue.h>

@@ -43,8 +44,18 @@ static const struct attribute_group etm_pmu_format_group = {
.attrs = etm_config_formats_attr,
};

+static struct attribute *etm_config_sinks_attr[] = {
+ NULL,
+};
+
+static const struct attribute_group etm_pmu_sinks_group = {
+ .name = "sinks",
+ .attrs = etm_config_sinks_attr,
+};
+
static const struct attribute_group *etm_pmu_attr_groups[] = {
&etm_pmu_format_group,
+ &etm_pmu_sinks_group,
NULL,
};

@@ -479,6 +490,77 @@ int etm_perf_symlink(struct coresight_device *csdev, bool link)
return 0;
}

+static ssize_t etm_perf_sink_name_show(struct device *dev,
+ struct device_attribute *dattr,
+ char *buf)
+{
+ struct dev_ext_attribute *ea;
+
+ ea = container_of(dattr, struct dev_ext_attribute, attr);
+ return scnprintf(buf, PAGE_SIZE, "0x%lx\n", (unsigned long)(ea->var));
+}
+
+int etm_perf_add_symlink_sink(struct coresight_device *csdev)
+{
+ int ret;
+ unsigned long hash;
+ const char *name;
+ struct device *pmu_dev = etm_pmu.dev;
+ struct device *pdev = csdev->dev.parent;
+ struct dev_ext_attribute *ea;
+
+ if (csdev->type != CORESIGHT_DEV_TYPE_SINK &&
+ csdev->type != CORESIGHT_DEV_TYPE_LINKSINK)
+ return -EINVAL;
+
+ if (csdev->ea != NULL)
+ return -EINVAL;
+
+ if (!etm_perf_up)
+ return -EPROBE_DEFER;
+
+ ea = devm_kzalloc(pdev, sizeof(*ea), GFP_KERNEL);
+ if (!ea)
+ return -ENOMEM;
+
+ name = dev_name(pdev);
+ /* See function coresight_get_sink_by_id() to know where this is used */
+ hash = hashlen_hash(hashlen_string(NULL, name));
+
+ ea->attr.attr.name = devm_kstrdup(pdev, name, GFP_KERNEL);
+ if (!ea->attr.attr.name)
+ return -ENOMEM;
+
+ ea->attr.attr.mode = 0444;
+ ea->attr.show = etm_perf_sink_name_show;
+ ea->var = (unsigned long *)hash;
+
+ ret = sysfs_add_file_to_group(&pmu_dev->kobj,
+ &ea->attr.attr, "sinks");
+
+ if (!ret)
+ csdev->ea = ea;
+
+ return ret;
+}
+
+void etm_perf_del_symlink_sink(struct coresight_device *csdev)
+{
+ struct device *pmu_dev = etm_pmu.dev;
+ struct dev_ext_attribute *ea = csdev->ea;
+
+ if (csdev->type != CORESIGHT_DEV_TYPE_SINK &&
+ csdev->type != CORESIGHT_DEV_TYPE_LINKSINK)
+ return;
+
+ if (!ea)
+ return;
+
+ sysfs_remove_file_from_group(&pmu_dev->kobj,
+ &ea->attr.attr, "sinks");
+ csdev->ea = NULL;
+}
+
static int __init etm_perf_init(void)
{
int ret;
diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.h b/drivers/hwtracing/coresight/coresight-etm-perf.h
index da7d9336a15c..015213abe00a 100644
--- a/drivers/hwtracing/coresight/coresight-etm-perf.h
+++ b/drivers/hwtracing/coresight/coresight-etm-perf.h
@@ -59,6 +59,8 @@ struct etm_event_data {

#ifdef CONFIG_CORESIGHT
int etm_perf_symlink(struct coresight_device *csdev, bool link);
+int etm_perf_add_symlink_sink(struct coresight_device *csdev);
+void etm_perf_del_symlink_sink(struct coresight_device *csdev);
static inline void *etm_perf_sink_config(struct perf_output_handle *handle)
{
struct etm_event_data *data = perf_get_aux(handle);
@@ -70,7 +72,9 @@ static inline void *etm_perf_sink_config(struct perf_output_handle *handle)
#else
static inline int etm_perf_symlink(struct coresight_device *csdev, bool link)
{ return -EINVAL; }
-
+int etm_perf_add_symlink_sink(struct coresight_device *csdev)
+{ return -EINVAL; }
+void etm_perf_del_symlink_sink(struct coresight_device *csdev) {}
static inline void *etm_perf_sink_config(struct perf_output_handle *handle)
{
return NULL;
diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c
index 2b0df1a0a8df..d7fa90be6f42 100644
--- a/drivers/hwtracing/coresight/coresight.c
+++ b/drivers/hwtracing/coresight/coresight.c
@@ -18,6 +18,7 @@
#include <linux/delay.h>
#include <linux/pm_runtime.h>

+#include "coresight-etm-perf.h"
#include "coresight-priv.h"

static DEFINE_MUTEX(coresight_mutex);
@@ -1167,6 +1168,22 @@ struct coresight_device *coresight_register(struct coresight_desc *desc)
goto err_out;
}

+ if (csdev->type == CORESIGHT_DEV_TYPE_SINK ||
+ csdev->type == CORESIGHT_DEV_TYPE_LINKSINK) {
+ ret = etm_perf_add_symlink_sink(csdev);
+
+ if (ret) {
+ device_unregister(&csdev->dev);
+ /*
+ * As with the above, all resources are free'd
+ * explicitly via coresight_device_release() triggered
+ * from put_device(), which is in turn called from
+ * function device_unregister().
+ */
+ goto err_out;
+ }
+ }
+
mutex_lock(&coresight_mutex);

coresight_fixup_device_conns(csdev);
@@ -1185,6 +1202,7 @@ EXPORT_SYMBOL_GPL(coresight_register);

void coresight_unregister(struct coresight_device *csdev)
{
+ etm_perf_del_symlink_sink(csdev);
/* Remove references of that device in the topology */
coresight_remove_conns(csdev);
device_unregister(&csdev->dev);
diff --git a/include/linux/coresight.h b/include/linux/coresight.h
index 46c67a764877..7b87965f7a65 100644
--- a/include/linux/coresight.h
+++ b/include/linux/coresight.h
@@ -154,8 +154,9 @@ struct coresight_connection {
* @orphan: true if the component has connections that haven't been linked.
* @enable: 'true' if component is currently part of an active path.
* @activated: 'true' only if a _sink_ has been activated. A sink can be
- activated but not yet enabled. Enabling for a _sink_
- happens when a source has been selected for that it.
+ * 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.
*/
struct coresight_device {
struct coresight_connection *conns;
@@ -168,7 +169,9 @@ struct coresight_device {
atomic_t *refcnt;
bool orphan;
bool enable; /* true only if configured as part of a path */
+ /* sink specific fields */
bool activated; /* true only if a sink is part of a path */
+ struct dev_ext_attribute *ea;
};

#define to_coresight_device(d) container_of(d, struct coresight_device, dev)
--
2.17.1
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