Create some infrastructure to aid trouble shooting device tree related
boot issues.
Add a %driver_name file to each device tree node sysfs directory which has had
a driver bound to it. This allows detecting device tree nodes which failed
to be bound to any driver.
Examples of using the %driver_name file (note that /proc/device-tree is a
link to the base of the device tree sysfs tree):
1) To find list of device tree nodes with no driver:
# A few false positives may be reported. For example,
# node_full_path of "." is the board.
#
# output is: node_full_path compatible_string
#
cd /proc/device-tree
for k in `find . -type d`; do
if [[ -f ${k}/compatible && ! -f ${k}/%driver_name ]] ; then
if [[ "`cat ${k}/compatible`" != "simple-bus" ]] ; then
echo `echo ${k} | sed -e 's|./||'` `cat ${k}/compatible`
fi
fi
done | sort
2) To find list of device tree nodes with a bound driver:
# output is: node_full_path driver_name
#
cd /proc/device-tree
for k in `find . -name %driver_name` ; do
echo `echo ${k} | sed -e 's|./||' -e 's|/%driver_name$||'` `cat ${k}`
done | sort
3) To find list of device tree nodes with a bound driver:
# output is: driver_name node_full_path
#
cd /proc/device-tree
for k in `find . -name %driver_name` ; do
echo `cat ${k}` `echo ${k} | sed -e 's|./||' -e 's|/%driver_name$||'`
done | sort
Signed-off-by: Frank Rowand <[email protected]>
---
Documentation/ABI/testing/sysfs-firmware-ofw | 17 +++++++-
drivers/base/dd.c | 5 ++
drivers/of/base.c | 55 +++++++++++++++++++++++++++
include/linux/of.h | 9 ++++
4 files changed, 85 insertions(+), 1 deletion(-)
Index: b/drivers/base/dd.c
===================================================================
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -25,6 +25,7 @@
#include <linux/kthread.h>
#include <linux/wait.h>
#include <linux/async.h>
+#include <linux/of.h>
#include <linux/pm_runtime.h>
#include <linux/pinctrl/devinfo.h>
@@ -194,6 +195,8 @@ static void driver_bound(struct device *
klist_add_tail(&dev->p->knode_driver, &dev->driver->p->klist_devices);
+ of_notify_driver_bound(dev);
+
/*
* Make sure the device is no longer in one of the deferred lists and
* kick off retrying all pending devices
@@ -505,6 +508,8 @@ static void __device_release_driver(stru
pm_runtime_put_sync(dev);
+ of_notify_driver_released(dev);
+
if (dev->bus && dev->bus->remove)
dev->bus->remove(dev);
else if (drv->remove)
Index: b/drivers/of/base.c
===================================================================
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -19,6 +19,7 @@
*/
#include <linux/ctype.h>
#include <linux/cpu.h>
+#include <linux/kallsyms.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_graph.h>
@@ -168,7 +169,61 @@ static void of_node_release(struct kobje
}
#endif /* CONFIG_OF_DYNAMIC */
+static ssize_t driver_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ return scnprintf(buf, PAGE_SIZE, "%s\n", dev->driver->name);
+}
+
+static const struct device_attribute of_driver_attr =
+ __ATTR(%driver_name, S_IRUGO, driver_show, NULL);
+
+void of_notify_driver_bound(struct device *dev)
+{
+ int err;
+
+ if (dev->of_node) {
+ dev->of_node->bound_dev = dev;
+ err = sysfs_create_file(&dev->of_node->kobj, &of_driver_attr.attr);
+ }
+
+}
+
+void of_notify_driver_released(struct device *dev)
+{
+ if (dev->of_node) {
+ sysfs_remove_file(&dev->of_node->kobj, &of_driver_attr.attr);
+ dev->of_node->bound_dev = NULL;
+ }
+}
+
+#define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
+
+static ssize_t of_node_attr_show(struct kobject *kobj, struct attribute *attr,
+ char *buf)
+{
+ struct device_attribute *dev_attr = to_dev_attr(attr);
+ struct device_node *np = container_of(kobj, struct device_node, kobj);
+ struct device *dev = np->bound_dev;
+
+ ssize_t ret = -EIO;
+
+ if (dev_attr->show)
+ ret = dev_attr->show(dev, dev_attr, buf);
+ if (ret >= (ssize_t)PAGE_SIZE) {
+ print_symbol("dev_attr_show: %s returned bad count\n",
+ (unsigned long)dev_attr->show);
+ }
+ return ret;
+}
+
+
+static const struct sysfs_ops of_node_sysfs_ops = {
+ .show = of_node_attr_show,
+};
+
struct kobj_type of_node_ktype = {
+ .sysfs_ops = &of_node_sysfs_ops,
.release = of_node_release,
};
Index: b/include/linux/of.h
===================================================================
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -60,6 +60,7 @@ struct device_node {
struct kobject kobj;
unsigned long _flags;
void *data;
+ struct device *bound_dev;
#if defined(CONFIG_SPARC)
const char *path_component_name;
unsigned int unique_id;
@@ -347,6 +348,9 @@ const char *of_prop_next_string(struct p
int of_device_is_stdout_path(struct device_node *dn);
+void of_notify_driver_bound(struct device *dev);
+void of_notify_driver_released(struct device *dev);
+
#else /* CONFIG_OF */
static inline const char* of_node_full_name(struct device_node *np)
@@ -571,6 +575,11 @@ static inline const char *of_prop_next_s
#define of_match_ptr(_ptr) NULL
#define of_match_node(_matches, _node) NULL
+
+void of_notify_driver_bound(struct device *dev) { }
+
+void of_notify_driver_released(struct device *dev) { }
+
#endif /* CONFIG_OF */
#if defined(CONFIG_OF) && defined(CONFIG_NUMA)
Index: b/Documentation/ABI/testing/sysfs-firmware-ofw
===================================================================
--- a/Documentation/ABI/testing/sysfs-firmware-ofw
+++ b/Documentation/ABI/testing/sysfs-firmware-ofw
@@ -25,4 +25,19 @@ Description:
directory name is the resolved path component name (node
name plus address). Properties are represented as files
in the directory. The contents of each file is the exact
- binary data from the device tree.
+ binary data from the device tree. Files that are exceptions
+ to this description will be described separately in this file.
+
+What: /sys/firmware/devicetree/.../%driver_name
+Date: April 2014
+KernelVersion: 3.15
+Contact: Frank Rowand <[email protected]>
+Description:
+ This file does not represent a device tree property. The file
+ will exist only if a driver is bound to the device tree node.
+ Reading from this file returns the name of the driver.
+
+ The apparently bizarre choice of prefixing the file name with
+ "%" is to avoid any possible conflict with a valid device tree
+ property name. ePAPR version 1.1 does not allow a property
+ name to contain the character "%".
On Tue, Apr 22, 2014 at 06:25:25PM -0700, Frank Rowand wrote:
> Create some infrastructure to aid trouble shooting device tree related
> boot issues.
>
> Add a %driver_name file to each device tree node sysfs directory which has had
> a driver bound to it. This allows detecting device tree nodes which failed
> to be bound to any driver.
Why is this needed, shouldn't there already be a "driver" symlink in
sysfs for these devices when a driver binds to them? The rest of the
driver model works that way, why is of devices any different?
> Examples of using the %driver_name file (note that /proc/device-tree is a
> link to the base of the device tree sysfs tree):
>
>
> 1) To find list of device tree nodes with no driver:
>
> # A few false positives may be reported. For example,
> # node_full_path of "." is the board.
> #
> # output is: node_full_path compatible_string
> #
> cd /proc/device-tree
> for k in `find . -type d`; do
> if [[ -f ${k}/compatible && ! -f ${k}/%driver_name ]] ; then
> if [[ "`cat ${k}/compatible`" != "simple-bus" ]] ; then
> echo `echo ${k} | sed -e 's|./||'` `cat ${k}/compatible`
> fi
> fi
> done | sort
>
>
> 2) To find list of device tree nodes with a bound driver:
>
> # output is: node_full_path driver_name
> #
> cd /proc/device-tree
> for k in `find . -name %driver_name` ; do
> echo `echo ${k} | sed -e 's|./||' -e 's|/%driver_name$||'` `cat ${k}`
> done | sort
>
>
> 3) To find list of device tree nodes with a bound driver:
>
> # output is: driver_name node_full_path
> #
> cd /proc/device-tree
> for k in `find . -name %driver_name` ; do
> echo `cat ${k}` `echo ${k} | sed -e 's|./||' -e 's|/%driver_name$||'`
> done | sort
If we take this patch, these examples should be somewhere in the
documentation to make it easy for others.
> Signed-off-by: Frank Rowand <[email protected]>
Minor nit, your From: line doesn't match this signed-off-by: so
something has to change (or add a new From: line, like SubmittingPatches
decribes how to do.)
thanks,
greg k-h
On Tue, 22 Apr 2014 20:20:44 -0700, Greg Kroah-Hartman <[email protected]> wrote:
> On Tue, Apr 22, 2014 at 06:25:25PM -0700, Frank Rowand wrote:
> > Create some infrastructure to aid trouble shooting device tree related
> > boot issues.
> >
> > Add a %driver_name file to each device tree node sysfs directory which has had
> > a driver bound to it. This allows detecting device tree nodes which failed
> > to be bound to any driver.
>
> Why is this needed, shouldn't there already be a "driver" symlink in
> sysfs for these devices when a driver binds to them? The rest of the
> driver model works that way, why is of devices any different?
>
Because it hasn't been added yet! I only just committed the change to
convert device_nodes into kobjects in v3.14. The next step is to add
driver symlinks.
That said, the devicetree node is already exposed in the uevent for a
device. It should already be possible to find all device tree nodes that
don't have a device, or devices without a driver:
To get a list of all nodes:
find /proc/device-tree/ -type d | sed -e 's/\/proc\/device-tree//'
or a little more nuanced, only choosing nodes with a compatible property:
for k in `find /proc/device-tree/ -name compatible`; do
echo $(dirname $k) | sed -e 's/\/proc\/device-tree//'
done | sort
It can get even more refined than that if need be.
To get a list of all nodes with a device that has been created:
for k in `find devices -name uevent`; do
grep '^OF_FULLNAME' $k | sed -e 's/OF_FULLNAME=//'
done | sort
To get a list of all nodes with a device that has been bound to a driver:
for k in `find devices -name uevent`; do
if [[ -d $(dirname $k)/driver ]]; then
grep '^OF_FULLNAME' $k | sed -e 's/OF_FULLNAME=//'
fi
done | sort
The suggestions you have below would be the anything in the first list
that isn't in the second or third:
bound=$(for k in `find /sys/devices -name uevent`; do
if [[ -d $(dirname $k)/driver ]]; then
grep '^OF_FULLNAME' $k | sed -e 's/OF_FULLNAME=//'
fi
done)
nodes=$(for k in `find /proc/device-tree/ -name compatible`; do
echo $(dirname $k) | sed -e 's/\/proc\/device-tree//'
done | sort)
for n in $nodes; do
if ! echo $bound | grep -q "$n"; then
echo $n $(cat /proc/device-tree/$n/compatible)
fi
done
> > Examples of using the %driver_name file (note that /proc/device-tree is a
> > link to the base of the device tree sysfs tree):
> >
> >
> > 1) To find list of device tree nodes with no driver:
> >
> > # A few false positives may be reported. For example,
> > # node_full_path of "." is the board.
> > #
> > # output is: node_full_path compatible_string
> > #
> > cd /proc/device-tree
> > for k in `find . -type d`; do
> > if [[ -f ${k}/compatible && ! -f ${k}/%driver_name ]] ; then
> > if [[ "`cat ${k}/compatible`" != "simple-bus" ]] ; then
> > echo `echo ${k} | sed -e 's|./||'` `cat ${k}/compatible`
> > fi
> > fi
> > done | sort
> >
> >
> > 2) To find list of device tree nodes with a bound driver:
> >
> > # output is: node_full_path driver_name
> > #
> > cd /proc/device-tree
> > for k in `find . -name %driver_name` ; do
> > echo `echo ${k} | sed -e 's|./||' -e 's|/%driver_name$||'` `cat ${k}`
> > done | sort
> >
> >
> > 3) To find list of device tree nodes with a bound driver:
> >
> > # output is: driver_name node_full_path
> > #
> > cd /proc/device-tree
> > for k in `find . -name %driver_name` ; do
> > echo `cat ${k}` `echo ${k} | sed -e 's|./||' -e 's|/%driver_name$||'`
> > done | sort
>
> If we take this patch, these examples should be somewhere in the
> documentation to make it easy for others.
>
> > Signed-off-by: Frank Rowand <[email protected]>
>
> Minor nit, your From: line doesn't match this signed-off-by: so
> something has to change (or add a new From: line, like SubmittingPatches
> decribes how to do.)
>
> thanks,
>
> greg k-h
On 4/22/2014 8:20 PM, Greg Kroah-Hartman wrote:
> On Tue, Apr 22, 2014 at 06:25:25PM -0700, Frank Rowand wrote:
>> Create some infrastructure to aid trouble shooting device tree related
>> boot issues.
>>
>> Add a %driver_name file to each device tree node sysfs directory which has had
>> a driver bound to it. This allows detecting device tree nodes which failed
>> to be bound to any driver.
>
> Why is this needed, shouldn't there already be a "driver" symlink in
> sysfs for these devices when a driver binds to them? The rest of the
> driver model works that way, why is of devices any different?
Yes, the devices do have a "driver" symlink in sysfs.
The problem I had was that I could not deterministically determine the
device name in /sysfs that was associated with a device tree node that
the device was created for. And I couldn't find a link from the device
tree entries to the device tree node.
Grant's reply to your email provided the solution to my problem; the
device uevents file contains the full device tree path of the associated
device tree node.
Grant's reply removes the need for my patch.
>
>> Examples of using the %driver_name file (note that /proc/device-tree is a
>> link to the base of the device tree sysfs tree):
>>
>>
>> 1) To find list of device tree nodes with no driver:
>>
>> # A few false positives may be reported. For example,
>> # node_full_path of "." is the board.
>> #
>> # output is: node_full_path compatible_string
>> #
>> cd /proc/device-tree
>> for k in `find . -type d`; do
>> if [[ -f ${k}/compatible && ! -f ${k}/%driver_name ]] ; then
>> if [[ "`cat ${k}/compatible`" != "simple-bus" ]] ; then
>> echo `echo ${k} | sed -e 's|./||'` `cat ${k}/compatible`
>> fi
>> fi
>> done | sort
>>
>>
>> 2) To find list of device tree nodes with a bound driver:
>>
>> # output is: node_full_path driver_name
>> #
>> cd /proc/device-tree
>> for k in `find . -name %driver_name` ; do
>> echo `echo ${k} | sed -e 's|./||' -e 's|/%driver_name$||'` `cat ${k}`
>> done | sort
>>
>>
>> 3) To find list of device tree nodes with a bound driver:
>>
>> # output is: driver_name node_full_path
>> #
>> cd /proc/device-tree
>> for k in `find . -name %driver_name` ; do
>> echo `cat ${k}` `echo ${k} | sed -e 's|./||' -e 's|/%driver_name$||'`
>> done | sort
>
> If we take this patch, these examples should be somewhere in the
> documentation to make it easy for others.
That is a good idea. I'll package up the equivalent shell code from
Grant's email. Any suggestions on location?
scripts/debug/devicetree/
scripts/devicetree/debug/
Documentation/devicetree/scripts/
If there is no good location in the kernel tree, then I will put them
either on the devicetree wiki, or the devicetree section of the
elinux wiki.
>
>> Signed-off-by: Frank Rowand <[email protected]>
>
> Minor nit, your From: line doesn't match this signed-off-by: so
> something has to change (or add a new From: line, like SubmittingPatches
> decribes how to do.)
Oops, thanks for pointing that out.
>
> thanks,
>
> greg k-h
-Frank
On 4/23/2014 4:54 AM, Grant Likely wrote:
> On Tue, 22 Apr 2014 20:20:44 -0700, Greg Kroah-Hartman <[email protected]> wrote:
>> On Tue, Apr 22, 2014 at 06:25:25PM -0700, Frank Rowand wrote:
>>> Create some infrastructure to aid trouble shooting device tree related
>>> boot issues.
>>>
>>> Add a %driver_name file to each device tree node sysfs directory which has had
>>> a driver bound to it. This allows detecting device tree nodes which failed
>>> to be bound to any driver.
>>
>> Why is this needed, shouldn't there already be a "driver" symlink in
>> sysfs for these devices when a driver binds to them? The rest of the
>> driver model works that way, why is of devices any different?
>>
>
> Because it hasn't been added yet! I only just committed the change to
> convert device_nodes into kobjects in v3.14. The next step is to add
> driver symlinks.
No need to add a "driver" symlink. The device directories in sysfs already
have a driver symlink.
>
> That said, the devicetree node is already exposed in the uevent for a
> device. It should already be possible to find all device tree nodes that
> don't have a device, or devices without a driver:
>
> To get a list of all nodes:
>
> find /proc/device-tree/ -type d | sed -e 's/\/proc\/device-tree//'
>
> or a little more nuanced, only choosing nodes with a compatible property:
>
> for k in `find /proc/device-tree/ -name compatible`; do
> echo $(dirname $k) | sed -e 's/\/proc\/device-tree//'
> done | sort
>
> It can get even more refined than that if need be.
>
> To get a list of all nodes with a device that has been created:
>
> for k in `find devices -name uevent`; do
> grep '^OF_FULLNAME' $k | sed -e 's/OF_FULLNAME=//'
> done | sort
< snip >
Thanks Grant! I did not realize that uevent contained that
information.
-Frank
On Wed, Apr 23, 2014 at 03:45:11PM -0700, Frank Rowand wrote:
> >> 3) To find list of device tree nodes with a bound driver:
> >>
> >> # output is: driver_name node_full_path
> >> #
> >> cd /proc/device-tree
> >> for k in `find . -name %driver_name` ; do
> >> echo `cat ${k}` `echo ${k} | sed -e 's|./||' -e 's|/%driver_name$||'`
> >> done | sort
> >
> > If we take this patch, these examples should be somewhere in the
> > documentation to make it easy for others.
>
> That is a good idea. I'll package up the equivalent shell code from
> Grant's email. Any suggestions on location?
>
> scripts/debug/devicetree/
> scripts/devicetree/debug/
> Documentation/devicetree/scripts/
tools/ is probably the best place for them, or in Documentation/, either
would work.
thanks,
greg k-h
On Wed, Apr 23, 2014 at 11:48 PM, Frank Rowand <[email protected]> wrote:
> On 4/23/2014 4:54 AM, Grant Likely wrote:
>> On Tue, 22 Apr 2014 20:20:44 -0700, Greg Kroah-Hartman <[email protected]> wrote:
>>> On Tue, Apr 22, 2014 at 06:25:25PM -0700, Frank Rowand wrote:
>>>> Create some infrastructure to aid trouble shooting device tree related
>>>> boot issues.
>>>>
>>>> Add a %driver_name file to each device tree node sysfs directory which has had
>>>> a driver bound to it. This allows detecting device tree nodes which failed
>>>> to be bound to any driver.
>>>
>>> Why is this needed, shouldn't there already be a "driver" symlink in
>>> sysfs for these devices when a driver binds to them? The rest of the
>>> driver model works that way, why is of devices any different?
>>>
>>
>> Because it hasn't been added yet! I only just committed the change to
>> convert device_nodes into kobjects in v3.14. The next step is to add
>> driver symlinks.
>
> No need to add a "driver" symlink. The device directories in sysfs already
> have a driver symlink.
Sorry, I meant of_node symlink. That is the bit I've been planning to add.
g.