[PATCH V3 5/6] coresight: adding sink parameter to function coresight_build_path()

Mathieu Poirier
2016-07-28T21:43:48Z

Up to now function coresight_build_path() was counting on a sink to
have been selected (from sysFS) prior to being called. This patch
adds a string argument so that a sink matching the argument can be
selected.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
drivers/hwtracing/coresight/coresight-etm-perf.c | 2 +-
drivers/hwtracing/coresight/coresight-priv.h | 3 +-
drivers/hwtracing/coresight/coresight.c | 43 ++++++++++++++++--------
3 files changed, 32 insertions(+), 16 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c
index f4174f36c5a0..f8c7a8733b23 100644
--- a/drivers/hwtracing/coresight/coresight-etm-perf.c
+++ b/drivers/hwtracing/coresight/coresight-etm-perf.c
@@ -184,7 +184,7 @@ static void *etm_setup_aux(struct perf_event *event, void **pages,
* list of devices from source to sink that can be
* referenced later when the path is actually needed.
*/
- event_data->path[cpu] = coresight_build_path(csdev);
+ event_data->path[cpu] = coresight_build_path(csdev, NULL);
if (!event_data->path[cpu])
goto err;
}
diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h
index ad975c58080d..3cb574b3cdd9 100644
--- a/drivers/hwtracing/coresight/coresight-priv.h
+++ b/drivers/hwtracing/coresight/coresight-priv.h
@@ -94,7 +94,8 @@ static inline void CS_UNLOCK(void __iomem *addr)
void coresight_disable_path(struct list_head *path);
int coresight_enable_path(struct list_head *path, u32 mode);
struct coresight_device *coresight_get_sink(struct list_head *path);
-struct list_head *coresight_build_path(struct coresight_device *csdev);
+struct list_head *coresight_build_path(struct coresight_device *csdev,
+ const char *sink);
void coresight_release_path(struct list_head *path);

#ifdef CONFIG_CORESIGHT_SOURCE_ETM3X
diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c
index d08d1ab9bba5..2b7196aa54c3 100644
--- a/drivers/hwtracing/coresight/coresight.c
+++ b/drivers/hwtracing/coresight/coresight.c
@@ -372,30 +372,44 @@ struct coresight_device *coresight_get_sink(struct list_head *path)
* _coresight_build_path - recursively build a path from a @csdev to a sink.
* @csdev: The device to start from.
* @path: The list to add devices to.
+ * @sink: The name of the sink this path should connect with.
*
- * The tree of Coresight device is traversed until an activated sink is
- * found. From there the sink is added to the list along with all the
- * devices that led to that point - the end result is a list from source
- * to sink. In that list the source is the first device and the sink the
- * last one.
+ * The tree of Coresight device is traversed until an activated sink or
+ * the one specified by @sink is found.
+ * From there the sink is added to the list along with all the devices that
+ * led to that point - the end result is a list from source to sink. In that
+ * list the source is the first device and the sink the last one.
*/
static int _coresight_build_path(struct coresight_device *csdev,
- struct list_head *path)
+ struct list_head *path, const char *sink)
{
int i;
bool found = false;
struct coresight_node *node;

- /* An activated sink has been found. Enqueue the element */
- if ((csdev->type == CORESIGHT_DEV_TYPE_SINK ||
- csdev->type == CORESIGHT_DEV_TYPE_LINKSINK) && csdev->activated)
- goto out;
+ /*
+ * First see if we are dealing with a sink. If we have one check if
+ * it was selected via sysFS or the perf cmd line.
+ */
+ if (csdev->type == CORESIGHT_DEV_TYPE_SINK ||
+ csdev->type == CORESIGHT_DEV_TYPE_LINKSINK) {
+ /* Discourage meddling in sysFS if using the perf interface */
+ if (sink && csdev->activated)
+ return -EINVAL;
+ /* Activated via perf cmd line */
+ if (sink && !strcmp(dev_name(&csdev->dev), sink))
+ goto out;
+ /* Activated via sysFS */
+ if (csdev->activated)
+ goto out;
+ }

/* Not a sink - recursively explore each port found on this element */
for (i = 0; i < csdev->nr_outport; i++) {
struct coresight_device *child_dev = csdev->conns[i].child_dev;

- if (child_dev && _coresight_build_path(child_dev, path) == 0) {
+ if (child_dev &&
+ _coresight_build_path(child_dev, path, sink) == 0) {
found = true;
break;
}
@@ -422,7 +436,8 @@ out:
return 0;
}

-struct list_head *coresight_build_path(struct coresight_device *csdev)
+struct list_head *coresight_build_path(struct coresight_device *csdev,
+ const char *sink)
{
struct list_head *path;
int rc;
@@ -433,7 +448,7 @@ struct list_head *coresight_build_path(struct coresight_device *csdev)

INIT_LIST_HEAD(path);

- rc = _coresight_build_path(csdev, path);
+ rc = _coresight_build_path(csdev, path, sink);
if (rc) {
kfree(path);
return ERR_PTR(rc);
@@ -508,7 +523,7 @@ int coresight_enable(struct coresight_device *csdev)
if (csdev->enable)
goto out;

- path = coresight_build_path(csdev);
+ path = coresight_build_path(csdev, NULL);
if (IS_ERR(path)) {
pr_err("building path(s) failed\n");
ret = PTR_ERR(path);
--
2.7.4