[PATCH 1/4] env: remove callback.o for an SPL build

[Rasmus Villemoes]

env.h says this about about callback declarations (U_BOOT_ENV_CALLBACK):

 * For SPL these are silently dropped to reduce code size, since environment
 * callbacks are not supported with SPL.

So env_callback_init() does a lot of work to not find anything in the
guaranteed empty env_clbk list. Drop callback.o entirely from the link
and stub out the only public function defined in callback.o. This cuts
about 600 bytes from the SPL on my ppc build.

Signed-off-by: Rasmus Villemoes <rasmus.villemoes at prevas.dk>
---
 env/Makefile           | 2 +-
 include/env_callback.h | 6 ++++++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/env/Makefile b/env/Makefile
index e2a165b8f1..c4ad654328 100644
--- a/env/Makefile
+++ b/env/Makefile
@@ -7,9 +7,9 @@ obj-$(CONFIG_$(SPL_TPL_)ENV_SUPPORT) += common.o
 obj-$(CONFIG_$(SPL_TPL_)ENV_SUPPORT) += env.o
 obj-$(CONFIG_$(SPL_TPL_)ENV_SUPPORT) += attr.o
 obj-$(CONFIG_$(SPL_TPL_)ENV_SUPPORT) += flags.o
-obj-$(CONFIG_$(SPL_TPL_)ENV_SUPPORT) += callback.o
 
 ifndef CONFIG_SPL_BUILD
+obj-y += callback.o
 obj-$(CONFIG_ENV_IS_IN_EEPROM) += eeprom.o
 extra-$(CONFIG_ENV_IS_EMBEDDED) += embedded.o
 obj-$(CONFIG_ENV_IS_IN_EEPROM) += embedded.o
diff --git a/include/env_callback.h b/include/env_callback.h
index 74da20eec3..05e9516a0f 100644
--- a/include/env_callback.h
+++ b/include/env_callback.h
@@ -72,6 +72,12 @@
 	"serial#:serialno," \
 	CONFIG_ENV_CALLBACK_LIST_STATIC
 
+#ifndef CONFIG_SPL_BUILD
 void env_callback_init(struct env_entry *var_entry);
+#else
+static inline void env_callback_init(struct env_entry *var_entry)
+{
+}
+#endif
 
 #endif /* __ENV_CALLBACK_H__ */
-- 
2.23.0