common/board_f: remove XTRN_DECLARE_GLOBAL_DATA_PTR dead code
The XTRN_DECLARE_GLOBAL_DATA_PTR declarations in ppc code are permanently
commented out, so there are no users for this macro:
#if 1
#define DECLARE_GLOBAL_DATA_PTR register volatile gd_t *gd asm ("r2")
#else /* We could use plain global data, but the resulting code is bigger */
#define XTRN_DECLARE_GLOBAL_DATA_PTR extern
#define DECLARE_GLOBAL_DATA_PTR XTRN_DECLARE_GLOBAL_DATA_PTR \
gd_t *gd
#endif
Remove all references to this macro, but add a documentation note regarding
the possibility of using plain global data for the GD pointer.
Signed-off-by: Ovidiu Panait <ovpanait@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/arch/powerpc/include/asm/global_data.h b/arch/powerpc/include/asm/global_data.h
index 6709e69..6ed21c7 100644
--- a/arch/powerpc/include/asm/global_data.h
+++ b/arch/powerpc/include/asm/global_data.h
@@ -92,12 +92,6 @@
#include <asm-generic/global_data.h>
-#if 1
#define DECLARE_GLOBAL_DATA_PTR register volatile gd_t *gd asm ("r2")
-#else /* We could use plain global data, but the resulting code is bigger */
-#define XTRN_DECLARE_GLOBAL_DATA_PTR extern
-#define DECLARE_GLOBAL_DATA_PTR XTRN_DECLARE_GLOBAL_DATA_PTR \
- gd_t *gd
-#endif
#endif /* __ASM_GBL_DATA_H */
diff --git a/common/board_f.c b/common/board_f.c
index 3df4efe..77b7d9e 100644
--- a/common/board_f.c
+++ b/common/board_f.c
@@ -59,18 +59,7 @@
#include <linux/errno.h>
#include <linux/log2.h>
-/*
- * Pointer to initial global data area
- *
- * Here we initialize it if needed.
- */
-#ifdef XTRN_DECLARE_GLOBAL_DATA_PTR
-#undef XTRN_DECLARE_GLOBAL_DATA_PTR
-#define XTRN_DECLARE_GLOBAL_DATA_PTR /* empty = allocate here */
-DECLARE_GLOBAL_DATA_PTR = (gd_t *)(CONFIG_SYS_INIT_GD_ADDR);
-#else
DECLARE_GLOBAL_DATA_PTR;
-#endif
/*
* TODO(sjg@chromium.org): IMO this code should be
diff --git a/doc/develop/global_data.rst b/doc/develop/global_data.rst
index 2ac893d..d143f27 100644
--- a/doc/develop/global_data.rst
+++ b/doc/develop/global_data.rst
@@ -36,6 +36,11 @@
The sandbox, x86_64, and Xtensa are notable exceptions.
+Current implementation uses a register for the GD pointer because this results
+in smaller code. However, using plain global data for the GD pointer would be
+possible too (and simpler, as it does not require the reservation of a specific
+register for it), but the resulting code is bigger.
+
Clang for ARM does not support assigning a global register. When using Clang
gd is defined as an inline function using assembly code. This adds a few bytes
to the code size.