[Skiboot] [PATCH v12 04/10] dt: Add phandle fixup helpers

[Madhavan Srinivasan]

On Tuesday 13 June 2017 11:47 AM, Michael Neuling wrote:
> On Sun, 2017-05-21 at 20:40 +0530, Madhavan Srinivasan wrote:
>> New subtree needs would have "phandle"
>> already assigned to some of it's nodes.
>> If this new substree is attached to main dt,
>> without fixing the phandles, would lead to
>> phandle duplicate errors.
> This commit message doesn't make a lot of sense to me.  Can you reword?

When there is a new device tree that needs to be added to
the main dt of the opal (ex, IMC catalog dtb loaded from pnor partition),
we need to check for the phandle values in the new incoming
device tree before attaching it. Reason is that, incoming device tree could
already have phandle values initialized for its nodes. Now, if we attach
this new device tree to the main opal DT, we could potentially hit phandle
duplicate error (since the phandles value usually start with 1).

To avoid this, a new helper function dt_adjust_subtree_phandle()
is added to scan the incoming device tree and update node
"phandle" accordingly based on the opal "last_phandle" value.

Add to this, helper function also supports updates of "properties"
with in a node which may refer the "phandle" value in the incoming
device tree. Helper function will also fix the "properties" field 
accordingly.


Maddy

>
> Also, can you fix the wrapping so it's around 80 column rather than (seemingly)
> 50?
>
>> Also, new subtree could have "properties"
>> refering to the phandle. So these "properties"
>> should also get updated accordingly when fixing
>> the "phandle".
>>
>> New helper dt_adjust_subtree_phandle() added to
>> core/device.c to do both. It does phandle fixup
>> with a single pass through the subtree.
>>
>> Patch also adds test in core/test/run-device.c
>> to exercise dt_fixup().
>>
>> Signed-off-by: Madhavan Srinivasan <maddy at linux.vnet.ibm.com>
>> ---
>>   core/device.c          | 38 ++++++++++++++++++++++++++++++++++++++
>>   core/test/run-device.c | 35 +++++++++++++++++++++++++++++++++--
>>   include/device.h       |  4 ++++
>>   3 files changed, 75 insertions(+), 2 deletions(-)
>>
>> diff --git a/core/device.c b/core/device.c
>> index 7211570e1b3c..7f2c94c10386 100644
>> --- a/core/device.c
>> +++ b/core/device.c
>> @@ -1069,3 +1069,41 @@ bool dt_node_is_enabled(struct dt_node *node)
>>   
>>   	return p->len > 1 && p->prop[0] == 'o' && p->prop[1] == 'k';
>>   }
>> +
>> +/*
>> + * Function to fixup the phandle in the subtree.
>> + */
>> +void dt_adjust_subtree_phandle(struct dt_node *dev,
>> +			const char** (get_properties_to_fix)(struct dt_node
>> *n))
>> +{
>> +	struct dt_node *node;
>> +	struct dt_property *prop;
>> +	u32 phandle, max_phandle = 0, import_phandle = new_phandle();
>> +	const char **name;
>> +
>> +	dt_for_each_node(dev, node) {
>> +		const char **props_to_update;
>> +		node->phandle += import_phandle;
>> +
>> +		/*
>> +		 * calculate max_phandle(new_tree), needed to update
>> +		 * last_phandle.
>> +		 */
>> +		if (node->phandle >= max_phandle)
>> +			max_phandle = node->phandle;
>> +
>> +		props_to_update = get_properties_to_fix(node);
>> +		if (props_to_update) {
>> +			for (name = props_to_update; *name != NULL; name++) {
>> +				prop = __dt_find_property(node, *name);
>> +				if (prop) {
>> +					phandle = dt_prop_get_u32(node,
>> *name);
>> +					phandle += import_phandle;
>> +					memcpy((char *)&prop->prop, &phandle,
>> prop->len);
>> +				}
>> +			}
>> +		}
>> +       }
>> +
>> +       set_last_phandle(max_phandle);
>> +}
>> diff --git a/core/test/run-device.c b/core/test/run-device.c
>> index 5939afc70e54..ffc8a4b9d1e1 100644
>> --- a/core/test/run-device.c
>> +++ b/core/test/run-device.c
>> @@ -33,6 +33,8 @@ static inline bool fake_is_rodata(const void *p)
>>   #include "../device.c"
>>   #include <assert.h>
>>   #include "../../test/dt_common.c"
>> +const char *prop_to_fix[] = {"something", NULL};
>> +const char **imc_prop_to_fix(struct dt_node *node);
>>   
>>   static void check_path(const struct dt_node *node, const char *
>> expected_path)
>>   {
>> @@ -87,18 +89,29 @@ static bool is_sorted(const struct dt_node *root)
>>   	return true;
>>   }
>>   
>> +/*handler for phandle fixup test */
>> +const char **imc_prop_to_fix(struct dt_node *node)
>> +{
>> +	const struct dt_property *prop;
>> +
>> +	prop = dt_find_property(node, "something");
>> +	if (prop)
>> +		return prop_to_fix;
>> +
>> +	return NULL;
>> +}
>>   
>>   int main(void)
>>   {
>>   	struct dt_node *root, *c1, *c2, *gc1, *gc2, *gc3, *ggc1, *ggc2;
>>   	struct dt_node *addrs, *addr1, *addr2;
>> -	struct dt_node *i;
>> +	struct dt_node *i, *subtree, *ev1, *ut1, *ut2;
>>   	const struct dt_property *p;
>>   	struct dt_property *p2;
>>   	unsigned int n;
>>   	char *s;
>>   	size_t sz;
>> -	u32 phandle;
>> +	u32 phandle, ev1_ph, new_prop_ph;
>>   
>>   	root = dt_new_root("");
>>   	assert(!list_top(&root->properties, struct dt_property, list));
>> @@ -412,6 +425,24 @@ int main(void)
>>   
>>   	dt_free(root);
>>   
>> +	/* phandle fixup test */
>> +	subtree = dt_new_root("subtree");
>> +	ev1 = dt_new(subtree, "ev at 1");
>> +	ev1_ph = ev1->phandle;
>> +	dt_new(ev1,"a at 1");
>> +	dt_new(ev1,"a at 2");
>> +	dt_new(ev1,"a at 3");
>> +	ut1 = dt_new(subtree, "ut at 1");
>> +	dt_add_property(ut1, "something", (const void *)&ev1->phandle, 4);
>> +	ut2 = dt_new(subtree, "ut at 2");
>> +	dt_add_property(ut2, "something", (const void *)&ev1->phandle, 4);
>> +
>> +	dt_adjust_subtree_phandle(subtree, imc_prop_to_fix);
>> +	assert(!(ev1->phandle == ev1_ph));
>> +	new_prop_ph = dt_prop_get_u32(ut1, "something");
>> +	assert(!(new_prop_ph == ev1_ph));
>> +	new_prop_ph = dt_prop_get_u32(ut2, "something");
>> +	assert(!(new_prop_ph == ev1_ph));
>>   	return 0;
>>   }
>>   
>> diff --git a/include/device.h b/include/device.h
>> index c51b3eea298e..1e5875dca584 100644
>> --- a/include/device.h
>> +++ b/include/device.h
>> @@ -268,4 +268,8 @@ struct dt_node *__dt_find_by_name_addr(struct dt_node
>> *parent, const char *name,
>>   struct dt_node *dt_find_by_name_addr(struct dt_node *parent, const char
>> *name,
>>   				uint64_t addr);
>>   
>> +/* phandle fixup helper */
>> +void dt_adjust_subtree_phandle(struct dt_node *subtree,
>> +				const char** (get_properties_to_fix)(struct
>> dt_node *n));
>> +
>>   #endif /* __DEVICE_H */