[PATCH v1] coresight: add node to reset all coresight devices

[Tao Zhang <taozha@codeaurora.org>]

Add new reset_source_sink node to be able to disable all active
coresight devices.
In this way, we no longer need to manually disable all active
coresight devices one by one. After enabling multiple coresight
paths, users can reset their status more conveniently by this
node.

This patch base on coresight-next repo
http://git.linaro.org/kernel/coresight.git/log/?h=next

And this patch depends on the following patch
https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg2551216.html

Signed-off-by: Tingwei Zhang <tingwei@codeaurora.org>
Signed-off-by: Mao Jinlong <jinlmao@codeaurora.org>
Signed-off-by: Tao Zhang <taozha@codeaurora.org>
---
 drivers/hwtracing/coresight/coresight-core.c | 72 ++++++++++++++++++++++++----
 1 file changed, 64 insertions(+), 8 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
index 7dfadb6..0001b6c 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -107,6 +107,23 @@ static int coresight_source_is_unique(struct coresight_device *csdev)
 				 csdev, coresight_id_match);
 }
 
+static int coresight_reset_sink(struct device *dev, void *data)
+{
+	struct coresight_device *csdev = to_coresight_device(dev);
+
+	if ((csdev->type == CORESIGHT_DEV_TYPE_SINK ||
+	     csdev->type == CORESIGHT_DEV_TYPE_LINKSINK) &&
+	     csdev->activated)
+		csdev->activated = false;
+
+	return 0;
+}
+
+static void coresight_reset_all_sink(void)
+{
+	bus_for_each_dev(&coresight_bustype, NULL, NULL, coresight_reset_sink);
+}
+
 static int coresight_find_link_inport(struct coresight_device *csdev,
 				      struct coresight_device *parent)
 {
@@ -1137,7 +1154,7 @@ int coresight_enable(struct coresight_device *csdev)
 }
 EXPORT_SYMBOL_GPL(coresight_enable);
 
-void coresight_disable(struct coresight_device *csdev)
+static void __coresight_disable(struct coresight_device *csdev)
 {
 	int  ret;
 	struct list_head *path = NULL;
@@ -1145,14 +1162,12 @@ void coresight_disable(struct coresight_device *csdev)
 	struct coresight_path *cspath_next = NULL;
 	struct coresight_device *src_csdev = NULL;
 
-	mutex_lock(&coresight_mutex);
-
 	ret = coresight_validate_source(csdev, __func__);
 	if (ret)
-		goto out;
+		return;
 
 	if (!csdev->enable || !coresight_disable_source(csdev))
-		goto out;
+		return;
 
 	list_for_each_entry_safe(cspath, cspath_next, &cs_active_paths, link) {
 		src_csdev = coresight_get_source(cspath->path);
@@ -1165,12 +1180,16 @@ void coresight_disable(struct coresight_device *csdev)
 		}
 	}
 	if (path == NULL)
-		goto out;
+		return;
 
 	coresight_disable_path(path);
 	coresight_release_path(path);
+}
 
-out:
+void coresight_disable(struct coresight_device *csdev)
+{
+	mutex_lock(&coresight_mutex);
+	__coresight_disable(csdev);
 	mutex_unlock(&coresight_mutex);
 }
 EXPORT_SYMBOL_GPL(coresight_disable);
@@ -1467,7 +1486,43 @@ int coresight_timeout(void __iomem *addr, u32 offset, int position, int value)
 
 	return -EAGAIN;
 }
-EXPORT_SYMBOL_GPL(coresight_timeout);
+
+static ssize_t reset_source_sink_store(struct bus_type *bus,
+				       const char *buf, size_t size)
+{
+	int ret = 0;
+	unsigned long val;
+	struct coresight_path *cspath = NULL;
+	struct coresight_path *cspath_next = NULL;
+	struct coresight_device *csdev;
+
+	ret = kstrtoul(buf, 10, &val);
+	if (ret)
+		return ret;
+
+	mutex_lock(&coresight_mutex);
+
+	list_for_each_entry_safe(cspath, cspath_next, &cs_active_paths, link) {
+		csdev = coresight_get_source(cspath->path);
+		if (!csdev)
+			continue;
+		atomic_set(csdev->refcnt, 1);
+		__coresight_disable(csdev);
+	}
+
+	/* Reset all activated sinks */
+	coresight_reset_all_sink();
+
+	mutex_unlock(&coresight_mutex);
+	return size;
+}
+static BUS_ATTR_WO(reset_source_sink);
+
+static struct attribute *coresight_reset_source_sink_attrs[] = {
+	&bus_attr_reset_source_sink.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(coresight_reset_source_sink);
 
 /*
  * coresight_release_platform_data: Release references to the devices connected
@@ -1680,6 +1735,7 @@ EXPORT_SYMBOL_GPL(coresight_alloc_device_name);
 
 struct bus_type coresight_bustype = {
 	.name	= "coresight",
+	.bus_groups	= coresight_reset_source_sink_groups,
 };
 
 static int __init coresight_init(void)
-- 
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