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Subject[PATCH 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>
---
.../hwtracing/coresight/coresight-etm-perf.c | 43 +++++++++++++++++++
.../hwtracing/coresight/coresight-etm-perf.h | 1 +
drivers/hwtracing/coresight/coresight.c | 17 ++++++++
3 files changed, 61 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c
index f21eb28b6782..292bd409a68c 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 +490,38 @@ 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)
+{
+ /* See function coresight_sink_by_id() to know where this is used */
+ u32 hash = hashlen_hash(hashlen_string(NULL, dattr->attr.name));
+
+ return scnprintf(buf, PAGE_SIZE, "%x\n", hash);
+}
+
+int etm_perf_symlink_sink(struct coresight_device *csdev)
+{
+ struct device *pmu_dev = etm_pmu.dev;
+ struct device *pdev = csdev->dev.parent;
+ struct device_attribute *dev_attr;
+
+ if (csdev->type != CORESIGHT_DEV_TYPE_SINK &&
+ csdev->type != CORESIGHT_DEV_TYPE_LINKSINK)
+ return -EINVAL;
+
+ if (!etm_perf_up)
+ return -EPROBE_DEFER;
+
+ dev_attr = kzalloc(sizeof(*dev_attr), GFP_KERNEL);
+ dev_attr->attr.name = kstrdup(dev_name(pdev), GFP_KERNEL);
+ dev_attr->attr.mode = 0444;
+ dev_attr->show = etm_perf_sink_name_show;
+
+ return sysfs_add_file_to_group(&pmu_dev->kobj,
+ &dev_attr->attr, "sinks");
+}
+
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..529a47285c0f 100644
--- a/drivers/hwtracing/coresight/coresight-etm-perf.h
+++ b/drivers/hwtracing/coresight/coresight-etm-perf.h
@@ -59,6 +59,7 @@ struct etm_event_data {

#ifdef CONFIG_CORESIGHT
int etm_perf_symlink(struct coresight_device *csdev, bool link);
+int etm_perf_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);
diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c
index 2b0df1a0a8df..526f122a38ee 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_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);
--
2.17.1
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