From: Ovidiu Panait <ovpanait@gmail.com>
Date: Tue, 13 Sep 2022 18:31:26 +0000 (+0300)
Subject: common/board_f: remove XTRN_DECLARE_GLOBAL_DATA_PTR dead code
X-Git-Url: http://git.dujemihanovic.xyz/?a=commitdiff_plain;h=181cbd4017305142eb26df0aa065b8bb95921f83;p=u-boot.git

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 6709e692e6..6ed21c781f 100644
--- a/arch/powerpc/include/asm/global_data.h
+++ b/arch/powerpc/include/asm/global_data.h
@@ -92,12 +92,6 @@ struct arch_global_data {
 
 #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 3df4efeeff..77b7d9e28c 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 2ac893de49..d143f27eed 100644
--- a/doc/develop/global_data.rst
+++ b/doc/develop/global_data.rst
@@ -36,6 +36,11 @@ On most architectures the global data pointer is stored in a register.
 
 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.