of/flattree: Add Kconfig for EARLY_FLATTREE

The device tree code is now in two pieces: some which can be used generically
on any platform which selects CONFIG_OF_FLATTREE, and some early which is used
at boot time on only a few architectures.  This patch segregates the early
code so that only those architectures which care about it need compile it.
This also means that some of the requirements in the early code (such as
a cmd_line variable) that most architectures (e.g. X86) don't provide
can be ignored.

Signed-off-by: Stephen Neuendorffer <stephen.neuendorffer@xilinx.com>
[grant.likely@secretlab.ca: remove extra blank line addition]
[grant.likely@secretlab.ca: fixed incorrect #ifdef CONFIG_EARLY_FLATTREE check]
[grant.likely@secretlab.ca: Made OF_EARLY_FLATTREE select instead of depend
                            on OF_FLATTREE]
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

arch/microblaze/Kconfig

@@ -14,7 +14,7 @@ config MICROBLAZE
 	select HAVE_DMA_API_DEBUG
 	select TRACING_SUPPORT
 	select OF
-	select OF_FLATTREE
+	select OF_EARLY_FLATTREE
 
 config SWAP
 	def_bool n

arch/mips/Kconfig

@@ -2218,7 +2218,7 @@ config SECCOMP
 config USE_OF
 	bool "Flattened Device Tree support"
 	select OF
-	select OF_FLATTREE
+	select OF_EARLY_FLATTREE
 	help
 	  Include support for flattened device tree machine descriptions.
 

arch/powerpc/Kconfig

@@ -116,7 +116,7 @@ config PPC
 	bool
 	default y
 	select OF
-	select OF_FLATTREE
+	select OF_EARLY_FLATTREE
 	select HAVE_FTRACE_MCOUNT_RECORD
 	select HAVE_DYNAMIC_FTRACE
 	select HAVE_FUNCTION_TRACER

drivers/of/Kconfig

@@ -19,6 +19,10 @@ config OF_FLATTREE
 	bool
 	select DTC
 
+config OF_EARLY_FLATTREE
+	bool
+	select OF_FLATTREE
+
 config OF_PROMTREE
 	bool
 

drivers/of/fdt.c

@@ -27,6 +27,8 @@ int __initdata dt_root_size_cells;
 
 struct boot_param_header *initial_boot_params;
 
+#ifdef CONFIG_OF_EARLY_FLATTREE
+
 char *find_flat_dt_string(u32 offset)
 {
 	return ((char *)initial_boot_params) +
@@ -604,3 +606,5 @@ void __init unflatten_device_tree(void)
 
 	pr_debug(" <- unflatten_device_tree()\n");
 }
+
+#endif /* CONFIG_OF_EARLY_FLATTREE */