On Tue, 22 Apr 2014 20:20:44 -0700, Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> 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 <frank.rowand@xxxxxxxxxxxxxx>
>
> 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
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