[Skiboot] [PATCH v12 06/23] core/fdt: Allow to exclude root node

[Gavin Shan]

The root node is excluded in the device sub-tree created during
PCI hot add time. This adds one extra argument @exclusive to
flatten_dt_node(), __create_dtb() and create_dtb() to indicate
the root node should be excluded or not. The changes are going
to be used by PCI hot add path and it's not affecting anything
at present.

Signed-off-by: Gavin Shan <gwshan at linux.vnet.ibm.com>
---
 core/fdt.c        | 29 ++++++++++++++++++-----------
 core/init.c       |  2 +-
 include/skiboot.h |  2 +-
 3 files changed, 20 insertions(+), 13 deletions(-)

diff --git a/core/fdt.c b/core/fdt.c
index fbfbac6..71149fe 100644
--- a/core/fdt.c
+++ b/core/fdt.c
@@ -130,17 +130,22 @@ static void flatten_dt_properties(void *fdt, const struct dt_node *dn)
 	}
 }
 
-static void flatten_dt_node(void *fdt, const struct dt_node *root)
+static void flatten_dt_node(void *fdt, const struct dt_node *root,
+			    bool exclusive)
 {
 	const struct dt_node *i;
 
-	FDT_DBG("node: %s\n", root->name);
-	dt_begin_node(fdt, root);
-	flatten_dt_properties(fdt, root);
+	if (!exclusive) {
+		FDT_DBG("node: %s\n", root->name);
+		dt_begin_node(fdt, root);
+		flatten_dt_properties(fdt, root);
+	}
+
 	list_for_each(&root->children, i, list)
-		flatten_dt_node(fdt, i);
+		flatten_dt_node(fdt, i, false);
 
-	dt_end_node(fdt);
+	if (!exclusive)
+		dt_end_node(fdt);
 }
 
 static void create_dtb_reservemap(void *fdt, const struct dt_node *root)
@@ -166,11 +171,13 @@ static void create_dtb_reservemap(void *fdt, const struct dt_node *root)
 }
 
 static int __create_dtb(void *fdt, size_t len,
-			const struct dt_node *root)
+			const struct dt_node *root,
+			bool exclusive)
 {
 	fdt_create(fdt, len);
-	create_dtb_reservemap(fdt, root);
-	flatten_dt_node(fdt, root);
+	if (root == dt_root && !exclusive)
+		create_dtb_reservemap(fdt, root);
+	flatten_dt_node(fdt, root, exclusive);
 
 	save_err(fdt_finish(fdt));
 	if (fdt_error) {
@@ -182,7 +189,7 @@ static int __create_dtb(void *fdt, size_t len,
 	return 0;
 }
 
-void *create_dtb(const struct dt_node *root)
+void *create_dtb(const struct dt_node *root, bool exclusive)
 {
 	void *fdt = NULL;
 	size_t len = DEVICE_TREE_MAX_SIZE;
@@ -198,7 +205,7 @@ void *create_dtb(const struct dt_node *root)
 			return NULL;
 		}
 
-		ret = __create_dtb(fdt, len, root);
+		ret = __create_dtb(fdt, len, root, exclusive);
 		if (ret) {
 			free(fdt);
 			fdt = NULL;
diff --git a/core/init.c b/core/init.c
index 4542a1d..67b539b 100644
--- a/core/init.c
+++ b/core/init.c
@@ -452,7 +452,7 @@ void __noreturn load_and_boot_kernel(bool is_reboot)
 	op_display(OP_LOG, OP_MOD_INIT, 0x000B);
 
 	/* Create the device tree blob to boot OS. */
-	fdt = create_dtb(dt_root);
+	fdt = create_dtb(dt_root, false);
 	if (!fdt) {
 		op_display(OP_FATAL, OP_MOD_INIT, 2);
 		abort();
diff --git a/include/skiboot.h b/include/skiboot.h
index a878d21..ded6bb8 100644
--- a/include/skiboot.h
+++ b/include/skiboot.h
@@ -251,7 +251,7 @@ extern void prd_init(void);
 extern void prd_register_reserved_memory(void);
 
 /* Flatten device-tree */
-extern void *create_dtb(const struct dt_node *root);
+extern void *create_dtb(const struct dt_node *root, bool exclusive);
 
 /* SLW reinit function for switching core settings */
 extern int64_t slw_reinit(uint64_t flags);
-- 
2.1.0