There is currently little to none information available
about the reasons why a v4l2-async device hasn't
probed completely.
Inspired by the "devices_deferred" debugfs file,
add a file to list information about the subdevices
that are on waiting lists, for each notifier.
This is useful to debug v4l2-async subdevices
and notifiers, for instance when doing device bring-up.
For instance, a typical output would be:
$ cat /sys/kernel/debug/video4linux/pending_async_subdevices
ipu1_csi1:
[fwnode] dev=20e0000.iomuxc-gpr:ipu1_csi1_mux, node=/soc/bus@2000000/iomuxc-gpr@20e0000/ipu1_csi1_mux
ipu1_csi0:
[fwnode] dev=20e0000.iomuxc-gpr:ipu1_csi0_mux, node=/soc/bus@2000000/iomuxc-gpr@20e0000/ipu1_csi0_mux
imx6-mipi-csi2:
[fwnode] dev=1-003c, node=/soc/bus@2100000/i2c@21a4000/camera@3c
imx-media:
Note that match-type "custom" prints no information.
Since there are no in-tree users of this match-type,
the implementation doesn't bother.
Signed-off-by: Ezequiel Garcia <ezequiel@xxxxxxxxxxxxx>
---
v2:
* Print fwnode path, as suggested by Sakari.
* Print the subdevices under their corresponding notifier.
* Rename the file as suggested by Laurent.
---
drivers/media/v4l2-core/v4l2-async.c | 66 ++++++++++++++++++++++++++++
drivers/media/v4l2-core/v4l2-dev.c | 5 +++
include/media/v4l2-async.h | 9 ++++
3 files changed, 80 insertions(+)
diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c
index e3ab003a6c85..d779808abb3b 100644
--- a/drivers/media/v4l2-core/v4l2-async.c
+++ b/drivers/media/v4l2-core/v4l2-async.c
@@ -5,6 +5,7 @@
* Copyright (C) 2012-2013, Guennadi Liakhovetski <g.liakhovetski@xxxxxx>
*/
+#include <linux/debugfs.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/i2c.h>
@@ -14,6 +15,7 @@
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/platform_device.h>
+#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/types.h>
@@ -837,3 +839,67 @@ void v4l2_async_unregister_subdev(struct v4l2_subdev *sd)
mutex_unlock(&list_lock);
}
EXPORT_SYMBOL(v4l2_async_unregister_subdev);
+
+static void print_waiting_subdev(struct seq_file *s,
+ struct v4l2_async_subdev *asd)
+{
+ switch (asd->match_type) {
+ case V4L2_ASYNC_MATCH_CUSTOM:
+ seq_puts(s, " [custom]\n");
+ break;
+ case V4L2_ASYNC_MATCH_DEVNAME:
+ seq_printf(s, " [devname] %s\n", asd->match.device_name);
+ break;
+ case V4L2_ASYNC_MATCH_I2C:
+ seq_printf(s, " [i2c] %d-%04x\n", asd->match.i2c.adapter_id,
+ asd->match.i2c.address);
+ break;
+ case V4L2_ASYNC_MATCH_FWNODE: {
+ struct fwnode_handle *fwnode = asd->match.fwnode;
+
+ if (fwnode_graph_is_endpoint(fwnode))
+ fwnode = fwnode_graph_get_port_parent(fwnode);
+
+ seq_printf(s, " [fwnode] dev=%s, node=%pfw\n",
+ fwnode->dev ? dev_name(fwnode->dev) : "nil",
+ fwnode);
+ break;
+ }
+ }
+}
+
+static const char *
+v4l2_async_notifier_name(struct v4l2_async_notifier *notifier)
+{
+ if (notifier->v4l2_dev)
+ return notifier->v4l2_dev->name;
+ else if (notifier->sd)
+ return notifier->sd->name;
+ else
+ return "nil";
+}
+
+static int pending_subdevs_show(struct seq_file *s, void *data)
+{
+ struct v4l2_async_notifier *notif;
+ struct v4l2_async_subdev *asd;
+
+ mutex_lock(&list_lock);
+
+ list_for_each_entry(notif, ¬ifier_list, list) {
+ seq_printf(s, "%s:\n", v4l2_async_notifier_name(notif));
+ list_for_each_entry(asd, ¬if->waiting, list)
+ print_waiting_subdev(s, asd);
+ }
+
+ mutex_unlock(&list_lock);
+
+ return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(pending_subdevs);
+
+void v4l2_async_debug_init(struct dentry *debugfs_dir)
+{
+ debugfs_create_file("pending_async_subdevices", 0444, debugfs_dir, NULL,
+ &pending_subdevs_fops);
+}
diff --git a/drivers/media/v4l2-core/v4l2-dev.c b/drivers/media/v4l2-core/v4l2-dev.c
index a593ea0598b5..8d3813e6ab56 100644
--- a/drivers/media/v4l2-core/v4l2-dev.c
+++ b/drivers/media/v4l2-core/v4l2-dev.c
@@ -14,6 +14,7 @@
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/debugfs.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
@@ -37,6 +38,7 @@
__func__, ##arg); \
} while (0)
+static struct dentry *v4l2_debugfs_dir;
/*
* sysfs stuff
@@ -1113,6 +1115,8 @@ static int __init videodev_init(void)
return -EIO;
}
+ v4l2_debugfs_dir = debugfs_create_dir("video4linux", NULL);
+ v4l2_async_debug_init(v4l2_debugfs_dir);
return 0;
}
@@ -1120,6 +1124,7 @@ static void __exit videodev_exit(void)
{
dev_t dev = MKDEV(VIDEO_MAJOR, 0);
+ debugfs_remove_recursive(v4l2_debugfs_dir);
class_unregister(&video_class);
unregister_chrdev_region(dev, VIDEO_NUM_DEVICES);
}
diff --git a/include/media/v4l2-async.h b/include/media/v4l2-async.h
index 0e04b5b2ebb0..abc85474bb3b 100644
--- a/include/media/v4l2-async.h
+++ b/include/media/v4l2-async.h
@@ -8,9 +8,11 @@
#ifndef V4L2_ASYNC_H
#define V4L2_ASYNC_H
+#include <linux/debugfs.h>
#include <linux/list.h>
#include <linux/mutex.h>
+struct dentry;
struct device;
struct device_node;
struct v4l2_device;
@@ -137,6 +139,13 @@ struct v4l2_async_notifier {
struct list_head list;
};
+/**
+ * v4l2_async_debug_init - Initialize debugging tools.
+ *
+ * @debugfs_dir: pointer to the parent debugfs &struct dentry
+ */
+void v4l2_async_debug_init(struct dentry *debugfs_dir);
+
/**
* v4l2_async_notifier_init - Initialize a notifier.
*
--
2.29.2
