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media: v4l2-async: Add waiting subdevices debugfs

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There is currently little to no 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:

Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
This commit is contained in:
Ezequiel Garcia 2021-01-08 18:17:28 +01:00 committed by Mauro Carvalho Chehab
parent 97cf50b6f8
commit 517fd2b6a0
3 changed files with 79 additions and 0 deletions
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66
drivers/media/v4l2-core/v4l2-async.c
View File

@ -5,6 +5,7 @@
* Copyright (C) 2012-2013, Guennadi Liakhovetski <g.liakhovetski@gmx.de>
*/
#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>
@ -831,3 +833,67 @@ 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_DEVNAME:
seq_printf(s, " [devname] dev=%s\n", asd->match.device_name);
break;
case V4L2_ASYNC_MATCH_I2C:
seq_printf(s, " [i2c] dev=%d-%04x\n", asd->match.i2c.adapter_id,
asd->match.i2c.address);
break;
case V4L2_ASYNC_MATCH_FWNODE: {
struct fwnode_handle *devnode, *fwnode = asd->match.fwnode;
devnode = fwnode_graph_is_endpoint(fwnode) ?
fwnode_graph_get_port_parent(fwnode) :
fwnode_handle_get(fwnode);
seq_printf(s, " [fwnode] dev=%s, node=%pfw\n",
devnode->dev ? dev_name(devnode->dev) : "nil",
fwnode);
fwnode_handle_put(devnode);
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, &notifier_list, list) {
seq_printf(s, "%s:\n", v4l2_async_notifier_name(notif));
list_for_each_entry(asd, &notif->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);
}

5
drivers/media/v4l2-core/v4l2-dev.c
View File

@ -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>
@ -38,6 +39,7 @@
__func__, ##arg); \
} while (0)
static struct dentry *v4l2_debugfs_dir;
/*
* sysfs stuff
@ -1118,6 +1120,8 @@ 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;
}
@ -1125,6 +1129,7 @@ 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);
}

8
include/media/v4l2-async.h
View File

@ -11,6 +11,7 @@
#include <linux/list.h>
#include <linux/mutex.h>
struct dentry;
struct device;
struct device_node;
struct v4l2_device;
@ -120,6 +121,13 @@ 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.
*