[U-Boot] [RFC][PATCH 27/36] x86 - Defer setup of final stack

[Graeme Russ]

---
 arch/i386/cpu/start.S |   44 +++++++++++++++++++++++++++++---------------
 arch/i386/lib/board.c |    6 ++++--
 2 files changed, 33 insertions(+), 17 deletions(-)

diff --git a/arch/i386/cpu/start.S b/arch/i386/cpu/start.S
index 95be5a2..77f0332 100644
--- a/arch/i386/cpu/start.S
+++ b/arch/i386/cpu/start.S
@@ -96,21 +96,6 @@ car_init_ret:
 	/* size memory */
 	call	dram_init_f

-	/* Setup stack in SDRAM */
-	movl	(GD_RAM_SIZE * 4)(%ebp), %esp
-
-	/* Test the stack */
-	pushl	$0
-	popl	%ecx
-	cmpl	$0, %ecx
-	jne	die
-	push	$0x55aa55aa
-	popl	%ecx
-	cmpl	$0x55aa55aa, %ecx
-	jne	die
-
-	wbinvd
-
 	/* Set parameter to board_init_f() to boot flags */
 	movl	(GD_FLAGS * 4)(%ebp), %eax

@@ -118,6 +103,35 @@ car_init_ret:

 	/* indicate (lack of) progress */
 	movw	$0x85, %ax
+	jmp	die
+
+.globl relocate_code
+.type relocate_code, @function
+relocate_code:
+	/*
+	 * SDRAM has been initialised, U-Boot code has been copied into
+	 * RAM, BSS has been cleared and relocation adjustments have been
+	 * made. It is now time to jump into the in-RAM copy of U-Boot
+	 *
+	 * %eax = Address of top of stack
+	 * %edx = Address of Global Data
+	 * %ecx = Base address of in-RAM copy of U-Boot
+	 */
+
+	/* Setup stack in RAM */
+	movl	%eax, %esp
+
+	/* Setup call address of in-RAM copy of board_init_r() */
+	movl	$board_init_r, %ebp
+	subl	(GD_RELOC_OFF * 4)(%edx), %ebp
+
+	/* Setup parameters to board_init_r() */
+	movl	%edx, %eax
+	movl	%ecx, %edx
+
+	/* Jump to in-RAM copy of board_init_r() */
+	call	*%ebp
+
 die:	hlt
 	jmp	die
 	hlt
diff --git a/arch/i386/lib/board.c b/arch/i386/lib/board.c
index 0dcd828..250bad8 100644
--- a/arch/i386/lib/board.c
+++ b/arch/i386/lib/board.c
@@ -189,6 +189,7 @@ void board_init_f (ulong boot_flags)
 	ulong *src_addr;
 	ulong *end_addr;

+	void *addr_sp;
 	void *dest_addr;
 	ulong rel_offset;
 	Elf32_Rel *re_src;
@@ -198,6 +199,7 @@ void board_init_f (ulong boot_flags)

 	/* Calculate destination RAM Address and relocation offset */
 	dest_addr = (void *)gd->ram_size;
+	addr_sp = dest_addr;
 	dest_addr -= CONFIG_SYS_STACK_SIZE;
 	dest_addr -= (bss_end - text_start);
 	rel_offset = text_start - dest_addr;
@@ -242,9 +244,9 @@ void board_init_f (ulong boot_flags)
 	gd->flags |= GD_FLG_RELOC;

 	/* Enter the relocated U-Boot! */
-	(board_init_r - rel_offset)(gd, (ulong)dest_addr);
+	relocate_code((ulong)addr_sp, gd, (ulong)dest_addr);

-	/* NOTREACHED - board_init_f() does not return */
+	/* NOTREACHED - relocate_code() does not return */
 	while(1);
 }

--
1.7.1.422.g049e9