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Subject: Re: [PATCH 05.1/16] of:overlay: missing name, phandle, linux,phandle
 in new nodes
From:   Frank Rowand <frowand.list@gmail.com>
To:     Alan Tull <atull@kernel.org>
Cc:     Rob Herring <robh+dt@kernel.org>,
        Pantelis Antoniou <pantelis.antoniou@konsulko.com>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Moritz Fischer <mdf@kernel.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>, linux-fpga@vger.kernel.org
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Date:   Wed, 10 Oct 2018 22:39:28 -0700
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On 10/10/18 14:03, Frank Rowand wrote:
> On 10/10/18 13:40, Alan Tull wrote:
>> On Wed, Oct 10, 2018 at 1:49 AM Frank Rowand <frowand.list@gmail.com> wrote:
>>>
>>> On 10/09/18 23:04, frowand.list@gmail.com wrote:
>>>> From: Frank Rowand <frank.rowand@sony.com>
>>>>
>>>>
>>>> "of: overlay: use prop add changeset entry for property in new nodes"
>>>> fixed a problem where an 'update property' changeset entry was
>>>> created for properties contained in nodes added by a changeset.
>>>> The fix was to use an 'add property' changeset entry.
>>>>
>>>> This exposed more bugs in the apply overlay code.  The properties
>>>> 'name', 'phandle', and 'linux,phandle' were filtered out by
>>>> add_changeset_property() as special properties.  Change the filter
>>>> to be only for existing nodes, not newly added nodes.
>>>>
>>>> The second bug is that the 'name' property does not exist in the
>>>> newest FDT version, and has to be constructed from the node's
>>>> full_name.  Construct an 'add property' changeset entry for
>>>> newly added nodes.
>>>>
>>>> Signed-off-by: Frank Rowand <frank.rowand@sony.com>
>>>> ---
>>>>
>>>>
>>>> Hi Alan,
>>>>
>>>> Thanks for reporting the problem with missing node names.
>>>>
>>>> I was able to replicate the problem, and have created this preliminary
>>>> version of a patch to fix the problem.
>>>>
>>>> I have not extensively reviewed the patch yet, but would appreciate
>>>> if you can confirm this fixes your problem.
>>>>
>>>> I created this patch as patch 17 of the series, but have also
>>>> applied it as patch 05.1, immediately after patch 05/16, and
>>>> built the kernel, booted, and verified name and phandle for
>>>> one of the nodes in a unittest overlay for both cases.  So
>>>> minimal testing so far on my part.
>>>>
>>>> I have not verified whether the series builds and boots after
>>>> each of patches 06..16 if this patch is applied as patch 05.1.
>>>>
>>>> There is definitely more work needed for me to complete this
>>>> patch because it allocates some more memory, but does not yet
>>>> free it when the overlay is released.
>>>>
>>>> -Frank
>>>>
>>>>
>>>>  drivers/of/overlay.c | 72 ++++++++++++++++++++++++++++++++++++++++++++++++----
>>>>  1 file changed, 67 insertions(+), 5 deletions(-)
>>>>
>>>> diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c
>>>> index 0b0904f44bc7..9746cea2aa91 100644
>>>> --- a/drivers/of/overlay.c
>>>> +++ b/drivers/of/overlay.c
>>>> @@ -301,10 +301,11 @@ static int add_changeset_property(struct overlay_changeset *ovcs,
>>>>       struct property *new_prop = NULL, *prop;
>>>>       int ret = 0;
>>>>
>>>> -     if (!of_prop_cmp(overlay_prop->name, "name") ||
>>>> -         !of_prop_cmp(overlay_prop->name, "phandle") ||
>>>> -         !of_prop_cmp(overlay_prop->name, "linux,phandle"))
>>>> -             return 0;
>>>> +     if (target->in_livetree)
>>>> +             if (!of_prop_cmp(overlay_prop->name, "name") ||
>>>> +                 !of_prop_cmp(overlay_prop->name, "phandle") ||
>>>> +                 !of_prop_cmp(overlay_prop->name, "linux,phandle"))
>>>> +                     return 0;
>>>
>>> This is a big hammer patch.
>>>
>>> Nobody should waste time reviewing this patch.
>>
>> I wasn't clear if you still could use the testing so I did re-run my
>> test.  This patch adds back some of the missing properties, but the
>> the kobject names aren't set as dev_name() returns NULL:
>>
>> * without this patch some of_node properties don't show up in sysfs:
>> root@arria10:~# ls
>> /sys/bus/platform/drivers/altera_freeze_br/ff200450.\<NULL\>/of_node
>> clocks            compatible        interrupt-parent  interrupts        reg
>>
>> * with this patch, the of_node properties phandle and name are back:
>> root@arria10:~#  ls
>> /sys/bus/platform/drivers/altera_freeze_br/ff200450.\<NULL\>/of_node
>> clocks            compatible        interrupt-parent  interrupts
>>  name              phandle           reg
> 
> Thanks for the testing.  I'll keep chasing after this problem today.
> 
> This is useful data for me as I was not looking under the /sys/bus/...
> tree that you reported, but was instead looking at /proc/device-tree/...
> which showed the same type of problem since the overlay I was using
> does not show up under /sys/bus/...
> 
> I'll have to create a useful overlay test case that will show up under
> /sys/bus/...
> 
> In the meantime, can you send me the base FDT and the overlay FDT for
> your test case?

I now have a test case that shows the problem under /sys/bus/... so I
no longer need the base FDT and overlay FDT for your test case.

I have determined the location that sets the name to "<NULL>" but do
not have the fix yet.  Still working on that.

-Frank

> 
> Thanks,
> 
> Frank
> 
> 
>>
>> root@arria10:~# cat
>> /sys/bus/platform/drivers/altera_freeze_br/ff200450.\<NULL\>/of_node/name
>> freeze_controllerroot@arria10:~#  ("freeze_controller" w/o the \n so
>> the name is correct)
>>
>> * with or without the patch I see the behavior I reported yesterday,
>> kobj names are NULL.
>> root@arria10:~# ls /sys/bus/platform/drivers/altera_freeze_br/
>> bind             ff200450.<NULL>  uevent           unbind
>>
>> root@arria10:~# ls /sys/bus/platform/drivers/altera_gpio/
>> bind             ff200010.<NULL>  ff200020.<NULL>  ff200030.<NULL>
>> uevent           unbind
>>
>> Alan
>>
>> Alan
>>
>>>
>>> The following part should not be needed (though the above section might have
>>> to become _slightly_ more complex).
>>>
>>> -Frank
>>>>
>>>>       if (target->in_livetree)
>>>>               prop = of_find_property(target->np, overlay_prop->name, NULL);
>>>> @@ -443,10 +444,13 @@ static int build_changeset_next_level(struct overlay_changeset *ovcs,
>>>>               struct target *target, const struct device_node *overlay_node)
>>>>  {
>>>>       struct device_node *child;
>>>> -     struct property *prop;
>>>> +     struct property *prop, *name_prop;
>>>> +     bool has_name = false;
>>>>       int ret;
>>>>
>>>>       for_each_property_of_node(overlay_node, prop) {
>>>> +             if (!strcmp(prop->name, "name"))
>>>> +                     has_name = true;
>>>>               ret = add_changeset_property(ovcs, target, prop, 0);
>>>>               if (ret) {
>>>>                       pr_debug("Failed to apply prop @%pOF/%s, err=%d\n",
>>>> @@ -455,6 +459,57 @@ static int build_changeset_next_level(struct overlay_changeset *ovcs,
>>>>               }
>>>>       }
>>>>
>>>> +     /*
>>>> +      * With FDT version 0x10 we may not have the name property,
>>>> +      * recreate it here from the unit name if absent
>>>> +      */
>>>> +
>>>> +     if (!has_name) {
>>>> +             const char *p = target->np->full_name, *ps = p, *pa = NULL;
>>>> +             int len;
>>>> +
>>>> +             /*
>>>> +              * zzz
>>>> +              * TODO: stash name_prop on a list in ovcs, to be freed
>>>> +              * after overlay removed
>>>> +              */
>>>> +
>>>> +             while (*p) {
>>>> +                     if ((*p) == '@')
>>>> +                             pa = p;
>>>> +                     else if ((*p) == '/')
>>>> +                             ps = p + 1;
>>>> +                     p++;
>>>> +             }
>>>> +
>>>> +             if (pa < ps)
>>>> +                     pa = p;
>>>> +             len = (pa - ps) + 1;
>>>> +
>>>> +             name_prop = kmalloc(sizeof(*name_prop), GFP_KERNEL);
>>>> +             if (!name_prop)
>>>> +                     return -ENOMEM;
>>>> +
>>>> +             name_prop->name = kstrdup("name", GFP_KERNEL);
>>>> +             name_prop->value = kmalloc(len, GFP_KERNEL);
>>>> +             if (!name_prop->name || !name_prop->value) {
>>>> +                     ret = -ENOMEM;
>>>> +                     goto err_free_name_prop;
>>>> +             }
>>>> +
>>>> +             memcpy(name_prop->value, ps, len - 1);
>>>> +             ((char *)name_prop->value)[len - 1] = 0;
>>>> +
>>>> +             name_prop->length = strlen(name_prop->value) + 1;
>>>> +
>>>> +             ret = add_changeset_property(ovcs, target, name_prop, 0);
>>>> +             if (ret) {
>>>> +                     pr_debug("Failed to apply name_prop @%pOF/%s, err=%d\n",
>>>> +                              target->np, name_prop->name, ret);
>>>> +                     goto err_free_name_prop;
>>>> +             }
>>>> +     }
>>>> +
>>>>       for_each_child_of_node(overlay_node, child) {
>>>>               ret = add_changeset_node(ovcs, target, child);
>>>>               if (ret) {
>>>> @@ -466,6 +521,13 @@ static int build_changeset_next_level(struct overlay_changeset *ovcs,
>>>>       }
>>>>
>>>>       return 0;
>>>> +
>>>> +err_free_name_prop:
>>>> +     kfree(name_prop->name);
>>>> +     kfree(name_prop->value);
>>>> +     kfree(name_prop);
>>>> +     return ret;
>>>> +
>>>>  }
>>>>
>>>>  /*
>>>>
>>>
>>
> 
>