Re: [PATCH 05/16] of: overlay: use prop add changeset entry for property in new nodes

[Frank Rowand]

On 10/09/18 13:28, Alan Tull wrote:
> On Thu, Oct 4, 2018 at 11:14 PM <frowand.list@xxxxxxxxx> wrote:
>>
>> From: Frank Rowand <frank.rowand@xxxxxxxx>
>>
> 
> Hi Frank,
> 
>> The changeset entry 'update property' was used for new properties in
>> an overlay instead of 'add property'.
>>
>> The decision of whether to use 'update property' was based on whether
>> the property already exists in the subtree where the node is being
>> spliced into.  At the top level of creating a changeset describing the
>> overlay, the target node is in the live devicetree, so checking whether
>> the property exists in the target node returns the correct result.
>> As soon as the changeset creation algorithm recurses into a new node,
>> the target is no longer in the live devicetree, but is instead in the
>> detached overlay tree, thus all properties are incorrectly found to
>> already exist in the target.
> 
> When I applied an overlay (that added a few gpio controllers, etc),
> the node names for nodes added from the overlay end up NULL.   It

I'll look at this tonight.

-Frank


> seems related to this patch and the next one.  I haven't completely
> root caused this but if I back out to before this patch, the situation
> is fixed.
> 
> root@arria10:~/unit_tests# ls /sys/bus/platform/drivers/altera_gpio/
> bind             ff200010.<NULL>  ff200020.<NULL>  ff200030.<NULL>
> uevent           unbind
> 
> root@arria10:~/unit_tests# ls /sys/bus/platform/drivers/altera_freeze_br/
> bind             ff200450.<NULL>  uevent           unbind
> 
> Alan
> 
>>
>> This fix will expose another devicetree bug that will be fixed
>> in the following patch in the series.
>>
>> When this patch is applied the errors reported by the devictree
>> unittest will change, and the unittest results will change from:
>>
>>    ### dt-test ### end of unittest - 210 passed, 0 failed
>>
>> to
>>
>>    ### dt-test ### end of unittest - 203 passed, 7 failed
>>
>> Signed-off-by: Frank Rowand <frank.rowand@xxxxxxxx>
>> ---
>>  drivers/of/overlay.c | 112 ++++++++++++++++++++++++++++++++++-----------------
>>  1 file changed, 74 insertions(+), 38 deletions(-)
>>
>> diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c
>> index 32cfee68f2e3..0b0904f44bc7 100644
>> --- a/drivers/of/overlay.c
>> +++ b/drivers/of/overlay.c
>> @@ -24,6 +24,26 @@
>>  #include "of_private.h"
>>
>>  /**
>> + * struct target - info about current target node as recursing through overlay
>> + * @np:                        node where current level of overlay will be applied
>> + * @in_livetree:       @np is a node in the live devicetree
>> + *
>> + * Used in the algorithm to create the portion of a changeset that describes
>> + * an overlay fragment, which is a devicetree subtree.  Initially @np is a node
>> + * in the live devicetree where the overlay subtree is targeted to be grafted
>> + * into.  When recursing to the next level of the overlay subtree, the target
>> + * also recurses to the next level of the live devicetree, as long as overlay
>> + * subtree node also exists in the live devicetree.  When a node in the overlay
>> + * subtree does not exist at the same level in the live devicetree, target->np
>> + * points to a newly allocated node, and all subsequent targets in the subtree
>> + * will be newly allocated nodes.
>> + */
>> +struct target {
>> +       struct device_node *np;
>> +       bool in_livetree;
>> +};
>> +
>> +/**
>>   * struct fragment - info about fragment nodes in overlay expanded device tree
>>   * @target:    target of the overlay operation
>>   * @overlay:   pointer to the __overlay__ node
>> @@ -72,8 +92,7 @@ static int devicetree_corrupt(void)
>>  }
>>
>>  static int build_changeset_next_level(struct overlay_changeset *ovcs,
>> -               struct device_node *target_node,
>> -               const struct device_node *overlay_node);
>> +               struct target *target, const struct device_node *overlay_node);
>>
>>  /*
>>   * of_resolve_phandles() finds the largest phandle in the live tree.
>> @@ -257,14 +276,17 @@ static struct property *dup_and_fixup_symbol_prop(
>>  /**
>>   * add_changeset_property() - add @overlay_prop to overlay changeset
>>   * @ovcs:              overlay changeset
>> - * @target_node:       where to place @overlay_prop in live tree
>> + * @target:            where @overlay_prop will be placed
>>   * @overlay_prop:      property to add or update, from overlay tree
>>   * @is_symbols_prop:   1 if @overlay_prop is from node "/__symbols__"
>>   *
>> - * If @overlay_prop does not already exist in @target_node, add changeset entry
>> - * to add @overlay_prop in @target_node, else add changeset entry to update
>> + * If @overlay_prop does not already exist in live devicetree, add changeset
>> + * entry to add @overlay_prop in @target, else add changeset entry to update
>>   * value of @overlay_prop.
>>   *
>> + * @target may be either in the live devicetree or in a new subtree that
>> + * is contained in the changeset.
>> + *
>>   * Some special properties are not updated (no error returned).
>>   *
>>   * Update of property in symbols node is not allowed.
>> @@ -273,20 +295,22 @@ static struct property *dup_and_fixup_symbol_prop(
>>   * invalid @overlay.
>>   */
>>  static int add_changeset_property(struct overlay_changeset *ovcs,
>> -               struct device_node *target_node,
>> -               struct property *overlay_prop,
>> +               struct target *target, struct property *overlay_prop,
>>                 bool is_symbols_prop)
>>  {
>>         struct property *new_prop = NULL, *prop;
>>         int ret = 0;
>>
>> -       prop = of_find_property(target_node, overlay_prop->name, NULL);
>> -
>>         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)
>> +               prop = of_find_property(target->np, overlay_prop->name, NULL);
>> +       else
>> +               prop = NULL;
>> +
>>         if (is_symbols_prop) {
>>                 if (prop)
>>                         return -EINVAL;
>> @@ -299,10 +323,10 @@ static int add_changeset_property(struct overlay_changeset *ovcs,
>>                 return -ENOMEM;
>>
>>         if (!prop)
>> -               ret = of_changeset_add_property(&ovcs->cset, target_node,
>> +               ret = of_changeset_add_property(&ovcs->cset, target->np,
>>                                                 new_prop);
>>         else
>> -               ret = of_changeset_update_property(&ovcs->cset, target_node,
>> +               ret = of_changeset_update_property(&ovcs->cset, target->np,
>>                                                    new_prop);
>>
>>         if (ret) {
>> @@ -315,14 +339,14 @@ static int add_changeset_property(struct overlay_changeset *ovcs,
>>
>>  /**
>>   * add_changeset_node() - add @node (and children) to overlay changeset
>> - * @ovcs:              overlay changeset
>> - * @target_node:       where to place @node in live tree
>> - * @node:              node from within overlay device tree fragment
>> + * @ovcs:      overlay changeset
>> + * @target:    where @overlay_prop will be placed in live tree or changeset
>> + * @node:      node from within overlay device tree fragment
>>   *
>> - * If @node does not already exist in @target_node, add changeset entry
>> - * to add @node in @target_node.
>> + * If @node does not already exist in @target, add changeset entry
>> + * to add @node in @target.
>>   *
>> - * If @node already exists in @target_node, and the existing node has
>> + * If @node already exists in @target, and the existing node has
>>   * a phandle, the overlay node is not allowed to have a phandle.
>>   *
>>   * If @node has child nodes, add the children recursively via
>> @@ -355,15 +379,16 @@ static int add_changeset_property(struct overlay_changeset *ovcs,
>>   * invalid @overlay.
>>   */
>>  static int add_changeset_node(struct overlay_changeset *ovcs,
>> -               struct device_node *target_node, struct device_node *node)
>> +               struct target *target, struct device_node *node)
>>  {
>>         const char *node_kbasename;
>>         struct device_node *tchild;
>> +       struct target target_child;
>>         int ret = 0;
>>
>>         node_kbasename = kbasename(node->full_name);
>>
>> -       for_each_child_of_node(target_node, tchild)
>> +       for_each_child_of_node(target->np, tchild)
>>                 if (!of_node_cmp(node_kbasename, kbasename(tchild->full_name)))
>>                         break;
>>
>> @@ -372,22 +397,28 @@ static int add_changeset_node(struct overlay_changeset *ovcs,
>>                 if (!tchild)
>>                         return -ENOMEM;
>>
>> -               tchild->parent = target_node;
>> +               tchild->parent = target->np;
>>                 of_node_set_flag(tchild, OF_OVERLAY);
>>
>>                 ret = of_changeset_attach_node(&ovcs->cset, tchild);
>>                 if (ret)
>>                         return ret;
>>
>> -               ret = build_changeset_next_level(ovcs, tchild, node);
>> +               target_child.np = tchild;
>> +               target_child.in_livetree = false;
>> +
>> +               ret = build_changeset_next_level(ovcs, &target_child, node);
>>                 of_node_put(tchild);
>>                 return ret;
>>         }
>>
>> -       if (node->phandle && tchild->phandle)
>> +       if (node->phandle && tchild->phandle) {
>>                 ret = -EINVAL;
>> -       else
>> -               ret = build_changeset_next_level(ovcs, tchild, node);
>> +       } else {
>> +               target_child.np = tchild;
>> +               target_child.in_livetree = target->in_livetree;
>> +               ret = build_changeset_next_level(ovcs, &target_child, node);
>> +       }
>>         of_node_put(tchild);
>>
>>         return ret;
>> @@ -396,7 +427,7 @@ static int add_changeset_node(struct overlay_changeset *ovcs,
>>  /**
>>   * build_changeset_next_level() - add level of overlay changeset
>>   * @ovcs:              overlay changeset
>> - * @target_node:       where to place @overlay_node in live tree
>> + * @target:            where to place @overlay_node in live tree
>>   * @overlay_node:      node from within an overlay device tree fragment
>>   *
>>   * Add the properties (if any) and nodes (if any) from @overlay_node to the
>> @@ -409,27 +440,26 @@ static int add_changeset_node(struct overlay_changeset *ovcs,
>>   * invalid @overlay_node.
>>   */
>>  static int build_changeset_next_level(struct overlay_changeset *ovcs,
>> -               struct device_node *target_node,
>> -               const struct device_node *overlay_node)
>> +               struct target *target, const struct device_node *overlay_node)
>>  {
>>         struct device_node *child;
>>         struct property *prop;
>>         int ret;
>>
>>         for_each_property_of_node(overlay_node, prop) {
>> -               ret = add_changeset_property(ovcs, target_node, prop, 0);
>> +               ret = add_changeset_property(ovcs, target, prop, 0);
>>                 if (ret) {
>>                         pr_debug("Failed to apply prop @%pOF/%s, err=%d\n",
>> -                                target_node, prop->name, ret);
>> +                                target->np, prop->name, ret);
>>                         return ret;
>>                 }
>>         }
>>
>>         for_each_child_of_node(overlay_node, child) {
>> -               ret = add_changeset_node(ovcs, target_node, child);
>> +               ret = add_changeset_node(ovcs, target, child);
>>                 if (ret) {
>>                         pr_debug("Failed to apply node @%pOF/%s, err=%d\n",
>> -                                target_node, child->name, ret);
>> +                                target->np, child->name, ret);
>>                         of_node_put(child);
>>                         return ret;
>>                 }
>> @@ -442,17 +472,17 @@ static int build_changeset_next_level(struct overlay_changeset *ovcs,
>>   * Add the properties from __overlay__ node to the @ovcs->cset changeset.
>>   */
>>  static int build_changeset_symbols_node(struct overlay_changeset *ovcs,
>> -               struct device_node *target_node,
>> +               struct target *target,
>>                 const struct device_node *overlay_symbols_node)
>>  {
>>         struct property *prop;
>>         int ret;
>>
>>         for_each_property_of_node(overlay_symbols_node, prop) {
>> -               ret = add_changeset_property(ovcs, target_node, prop, 1);
>> +               ret = add_changeset_property(ovcs, target, prop, 1);
>>                 if (ret) {
>>                         pr_debug("Failed to apply prop @%pOF/%s, err=%d\n",
>> -                                target_node, prop->name, ret);
>> +                                target->np, prop->name, ret);
>>                         return ret;
>>                 }
>>         }
>> @@ -475,6 +505,7 @@ static int build_changeset_symbols_node(struct overlay_changeset *ovcs,
>>  static int build_changeset(struct overlay_changeset *ovcs)
>>  {
>>         struct fragment *fragment;
>> +       struct target target;
>>         int fragments_count, i, ret;
>>
>>         /*
>> @@ -489,7 +520,9 @@ static int build_changeset(struct overlay_changeset *ovcs)
>>         for (i = 0; i < fragments_count; i++) {
>>                 fragment = &ovcs->fragments[i];
>>
>> -               ret = build_changeset_next_level(ovcs, fragment->target,
>> +               target.np = fragment->target;
>> +               target.in_livetree = true;
>> +               ret = build_changeset_next_level(ovcs, &target,
>>                                                  fragment->overlay);
>>                 if (ret) {
>>                         pr_debug("apply failed '%pOF'\n", fragment->target);
>> @@ -499,7 +532,10 @@ static int build_changeset(struct overlay_changeset *ovcs)
>>
>>         if (ovcs->symbols_fragment) {
>>                 fragment = &ovcs->fragments[ovcs->count - 1];
>> -               ret = build_changeset_symbols_node(ovcs, fragment->target,
>> +
>> +               target.np = fragment->target;
>> +               target.in_livetree = true;
>> +               ret = build_changeset_symbols_node(ovcs, &target,
>>                                                    fragment->overlay);
>>                 if (ret) {
>>                         pr_debug("apply failed '%pOF'\n", fragment->target);
>> @@ -517,7 +553,7 @@ static int build_changeset(struct overlay_changeset *ovcs)
>>   * 1) "target" property containing the phandle of the target
>>   * 2) "target-path" property containing the path of the target
>>   */
>> -static struct device_node *find_target_node(struct device_node *info_node)
>> +static struct device_node *find_target(struct device_node *info_node)
>>  {
>>         struct device_node *node;
>>         const char *path;
>> @@ -623,7 +659,7 @@ static int init_overlay_changeset(struct overlay_changeset *ovcs,
>>
>>                 fragment = &fragments[cnt];
>>                 fragment->overlay = overlay_node;
>> -               fragment->target = find_target_node(node);
>> +               fragment->target = find_target(node);
>>                 if (!fragment->target) {
>>                         of_node_put(fragment->overlay);
>>                         ret = -EINVAL;
>> --
>> Frank Rowand <frank.rowand@xxxxxxxx>
>>
>