coresight_enable_path() enables helpers attached to every device in the path, including those bound to the source. However, coresight_disable_path() skips the source node, so source helpers had to be disabled separately in coresight_disable_source().
Move source helper disabling into coresight_disable_path() instead. Make coresight_disable_path_from() start from the passed node nd, so it can also disable helpers on the source. Update the comments accordingly.
As coresight_disable_path_from() now changes its semantics from "start beyond nd" to "start from nd", update the failure handling in coresight_enable_path(). If enabling a node fails, iterate to the previous node (the last successfully enabled one) and pass it to coresight_disable_path_from() for rollback.
Tested-by: Jie Gan jie.gan@oss.qualcomm.com Reviewed-by: Yeoreum Yun yeoreum.yun@arm.com Reviewed-by: James Clark james.clark@linaro.org Tested-by: James Clark james.clark@linaro.org Signed-off-by: Leo Yan leo.yan@arm.com --- drivers/hwtracing/coresight/coresight-core.c | 27 ++++++++------------------- 1 file changed, 8 insertions(+), 19 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c index c525ecaad7efc40150d2d8ef3a6decddb68aff69..856036ad838b3508bf39a2ef40e68673925bca5b 100644 --- a/drivers/hwtracing/coresight/coresight-core.c +++ b/drivers/hwtracing/coresight/coresight-core.c @@ -456,19 +456,12 @@ static void coresight_disable_helpers(struct coresight_device *csdev, }
/* - * Helper function to call source_ops(csdev)->disable and also disable the - * helpers. - * - * There is an imbalance between coresight_enable_path() and - * coresight_disable_path(). Enabling also enables the source's helpers as part - * of the path, but disabling always skips the first item in the path (which is - * the source), so sources and their helpers don't get disabled as part of that - * function and we need the extra step here. + * coresight_disable_source() only disables the source, but do nothing for + * the associated helpers, which are controlled as part of the path. */ void coresight_disable_source(struct coresight_device *csdev, void *data) { source_ops(csdev)->disable(csdev, data); - coresight_disable_helpers(csdev, NULL); } EXPORT_SYMBOL_GPL(coresight_disable_source);
@@ -495,9 +488,9 @@ int coresight_resume_source(struct coresight_device *csdev) EXPORT_SYMBOL_GPL(coresight_resume_source);
/* - * coresight_disable_path_from : Disable components in the given path beyond - * @nd in the list. If @nd is NULL, all the components, except the SOURCE are - * disabled. + * coresight_disable_path_from : Disable components in the given path starting + * from @nd in the list. If @nd is NULL, all the components, except the SOURCE + * are disabled. */ static void coresight_disable_path_from(struct coresight_path *path, struct coresight_node *nd) @@ -508,7 +501,7 @@ static void coresight_disable_path_from(struct coresight_path *path, if (!nd) nd = list_first_entry(&path->path_list, struct coresight_node, link);
- list_for_each_entry_continue(nd, &path->path_list, link) { + list_for_each_entry_from(nd, &path->path_list, link) { csdev = nd->csdev; type = csdev->type;
@@ -528,12 +521,6 @@ static void coresight_disable_path_from(struct coresight_path *path, coresight_disable_sink(csdev); break; case CORESIGHT_DEV_TYPE_SOURCE: - /* - * We skip the first node in the path assuming that it - * is the source. So we don't expect a source device in - * the middle of a path. - */ - WARN_ON(1); break; case CORESIGHT_DEV_TYPE_LINK: parent = list_prev_entry(nd, link)->csdev; @@ -648,6 +635,8 @@ int coresight_enable_path(struct coresight_path *path, enum cs_mode mode) err_disable_helpers: coresight_disable_helpers(csdev, path); err_disable_path: + /* Fetch the previous node, the last successfully enabled one */ + nd = list_next_entry(nd, link); coresight_disable_path_from(path, nd); goto out; }