[Skiboot] [PATCH v9 05/11] dt: Add phandle fixup helpers

[Anju T Sudhakar]

Patch to add a phandle fixup function for a new
incoming subtree. When attaching a "subtree" to
main dt, subtree could have "property" referring
different nodes or multiple nodes via phandle as
"labels". For this reason, new subtree will have
"phandle" already assigned to some of it's nodes.
If this new subtree is attached to main dt without
phandle fixup, could lead to duplicate phandle errors

dt_fixup_populate_hash() does two main things. It first
uses a hash primitive to create a hashtable using phandle
as key. It then loops through the list of properties specified
as an input to this function (which needs to be fixed up),
and calls the fixup "handler".

Signed-off-by: Anju T Sudhakar <anju at linux.vnet.ibm.com>
Signed-off-by: Madhavan Srinivasan <maddy at linux.vnet.ibm.com>
---
 core/device.c    | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 include/device.h | 19 +++++++++++++++++++
 2 files changed, 66 insertions(+)

diff --git a/core/device.c b/core/device.c
index 170e0ee..e933c27 100644
--- a/core/device.c
+++ b/core/device.c
@@ -17,6 +17,7 @@
 #include <device.h>
 #include <stdlib.h>
 #include <skiboot.h>
+#include <hash.h>
 #include <libfdt/libfdt.h>
 #include <libfdt/libfdt_internal.h>
 #include <ccan/str/str.h>
@@ -849,6 +850,52 @@ void dt_expand(const void *fdt)
 		abort();
 }
 
+/* dt_fixup_populate_hash: populate the hash table, and invoke the fixup-handler
+ *			   to fixup the phandle value of the nodes.
+ */
+int dt_fixup_populate_hash(struct dt_node *dev, hash_table_p hash, phandle_fixup_p list_prop )
+{
+	struct dt_node *node;
+	hash_entry_p entry;
+	fixup_prop_list *list_pp;
+	u32 phandle;
+	phandle_fixup_n *val;
+
+	/* Initialize the hashtable */
+	hash_init(hash);
+
+	/* For each node of 'dev', insert the node-phandle pair into hashtable */
+	dt_for_each_node(dev, node) {
+		if (node->phandle > 0) {
+			val = (phandle_fixup_n *)malloc(sizeof(phandle_fixup_n));
+			if(!val) {
+				prerror("Failed to allocate memory");
+				return -1;
+			}
+			val->node = node;
+			val->fixed = false;
+			entry = hash_insert_entry(hash, node->phandle, val);
+			if(!entry) {
+				prerror("Failed to make hash table entry");
+				return -1;
+			}
+		}
+	}
+	list_for_each(&list_prop->list, list_pp, list) {
+		phandle = dt_prop_get_u32(list_pp->node, list_pp->prop->name);
+		/* look for the entry, with phandle as the key to hashtable */
+		entry = hash_lookup_entry(hash, phandle);
+		if (entry) {
+			/* If find a valid entry in the hashtable, do the fixup */
+			list_prop->fixup(entry, list_pp->prop);
+		} else {
+			prerror("%s: Missing hash entry phandle = %x\n", __FUNCTION__, phandle);
+			return -1;
+		}
+	}
+	return 0;
+}
+
 u64 dt_get_number(const void *pdata, unsigned int cells)
 {
 	const u32 *p = pdata;
diff --git a/include/device.h b/include/device.h
index f659675..40c961a 100644
--- a/include/device.h
+++ b/include/device.h
@@ -19,6 +19,7 @@
 #include <ccan/list/list.h>
 #include <ccan/short_types/short_types.h>
 #include <compiler.h>
+#include <hash.h>
 
 /* Any property or node with this prefix will not be passed to the kernel. */
 #define DT_PRIVATE	"skiboot,"
@@ -47,6 +48,22 @@ struct dt_node {
 	u32 phandle;
 };
 
+typedef struct dt_phandle_fixup_prop_list {
+	struct dt_node *node;
+	const struct dt_property *prop;
+	struct list_node list;
+} fixup_prop_list;
+
+typedef struct dt_phandle_fixup {
+	struct list_head list;
+	void (*fixup) (hash_entry_p entry, const struct dt_property *prop);
+} phandle_fixup_s, *phandle_fixup_p;
+
+typedef struct dt_phandle_fixup_entry_node {
+	struct dt_node *node;
+	bool fixed;
+} phandle_fixup_n;
+
 /* This is shared with device_tree.c .. make it static when
  * the latter is gone (hopefully soon)
  */
@@ -262,5 +279,7 @@ u64 dt_translate_address(const struct dt_node *node, unsigned int index,
  * tree. This is mainly here for testing.
  */
 int dt_cmp_subnodes(const struct dt_node *a,  const struct dt_node *b);
+/* phandle fixup function for a new incoming subtree */
+int dt_fixup_populate_hash(struct dt_node *dev, hash_table_p hash, phandle_fixup_p list_prop);
 
 #endif /* __DEVICE_H */
-- 
2.7.4