X-Git-Url: https://git.karo-electronics.de/?a=blobdiff_plain;f=arch%2Fi386%2Fcpu%2Fstart.S;h=cff463758940ebbdda7992e57b11e81c3d5daef9;hb=161b3589ea19ad262a2eebbf7b4f10aeb6812f35;hp=1980f1a7b7800405816a5e5c3be00499eb8b628b;hpb=759598f82f02cc84614450807cb5de43ca18a339;p=karo-tx-uboot.git

diff --git a/arch/i386/cpu/start.S b/arch/i386/cpu/start.S
index 1980f1a7b7..cff4637589 100644
--- a/arch/i386/cpu/start.S
+++ b/arch/i386/cpu/start.S
@@ -1,7 +1,7 @@
 /*
  *  U-boot - i386 Startup Code
  *
- *  Copyright (c) 2002	Omicron Ceti AB, Daniel Engström <denaiel@omicron.se>
+ *  Copyright (c) 2002	Omicron Ceti AB, Daniel Engstr�m <denaiel@omicron.se>
  *
  * See file CREDITS for list of people who contributed to this
  * project.
@@ -25,6 +25,7 @@
 
 #include <config.h>
 #include <version.h>
+#include <asm/global_data.h>
 
 
 .section .text
@@ -33,108 +34,115 @@
 .type _start, @function
 .globl _i386boot_start
 _i386boot_start:
+	/*
+	 * This is the fail safe 32-bit bootstrap entry point. The
+	 * following code is not executed from a cold-reset (actually, a
+	 * lot of it is, but from real-mode after cold reset. It is
+	 * repeated here to put the board into a state as close to cold
+	 * reset as necessary)
+	 */
+	cli
+	cld
+
+	/* Turn of cache (this might require a 486-class CPU) */
+	movl	%cr0, %eax
+	orl	$0x60000000, %eax
+	movl	%eax, %cr0
+	wbinvd
+
+	/* Tell 32-bit code it is being entered from an in-RAM copy */
+	movw	$0x0000, %bx
 _start:
-	movl    $0x18,%eax	/* Load our segement registes, the
+	/* This is the 32-bit cold-reset entry point */
+
+	movl	$0x18, %eax	/* Load our segement registes, the
 				 * gdt have already been loaded by start16.S */
-	movw    %ax,%fs
-	movw	%ax,%ds
-	movw    %ax,%gs
-	movw    %ax,%es
-	movw    %ax,%ss
+	movw	%ax, %fs
+	movw	%ax, %ds
+	movw	%ax, %gs
+	movw	%ax, %es
+	movw	%ax, %ss
+
+	/* Clear the interupt vectors */
+	lidt	blank_idt_ptr
+
+	/*
+	 * Skip low-level board and memory initialization if not starting
+	 * from cold-reset. This allows us to do a fail safe boot-strap
+	 * into a new build of U-Boot from a known-good boot flash
+	 */
+	movw	$0x0001, %ax
+	cmpw	%ax, %bx
+	jne	mem_init_ret
 
 	/* We call a few functions in the board support package
 	 * since we have no stack yet we'll have to use %ebp
 	 * to store the return address */
 
 	/* Early platform init (setup gpio, etc ) */
-	mov     $early_board_init_ret, %ebp
 	jmp	early_board_init
+.globl early_board_init_ret
 early_board_init_ret:
 
-	/* The __port80 entry-point should be usabe by now */
-	/* so we try to indicate progress */
-	movw	$0x01, %ax
-	movl	$.progress0, %ebp
-	jmp	show_boot_progress_asm
-.progress0:
-
 	/* size memory */
-	mov	$mem_init_ret, %ebp
-	jmp     mem_init
+	jmp	mem_init
+.globl mem_init_ret
 mem_init_ret:
 
 	/* fetch memory size (into %eax) */
-	mov	$get_mem_size_ret, %ebp
-	jmp     get_mem_size
+	jmp	get_mem_size
+.globl get_mem_size_ret
 get_mem_size_ret:
 
+#if CONFIG_SYS_SDRAM_ECC_ENABLE
+	/* Skip ECC initialization if not starting from cold-reset */
+	movl	%ebx, %ecx
+	andl	$GD_FLG_COLD_BOOT, %ecx
+	jz	init_ecc_ret
+	jmp	init_ecc
+
+.globl init_ecc_ret
+init_ecc_ret:
+#endif
+
 	/* Check we have enough memory for stack */
 	movl	$CONFIG_SYS_STACK_SIZE, %ecx
 	cmpl	%ecx, %eax
-	jae	mem_ok
-
-	/* indicate (lack of) progress */
-	movw	$0x81, %ax
-	movl	$.progress0a, %ebp
-	jmp	show_boot_progress_asm
-.progress0a:
-	jmp	die
+	jb	die
 mem_ok:
 	/* Set stack pointer to upper memory limit*/
-	movl    %eax, %esp
-
-	/* indicate progress */
-	movw	$0x02, %ax
-	movl	$.progress1, %ebp
-	jmp	show_boot_progress_asm
-.progress1:
+	movl	%eax, %esp
 
 	/* Test the stack */
 	pushl	$0
-	popl	%eax
-	cmpl	$0, %eax
-	jne	no_stack
+	popl	%ecx
+	cmpl	$0, %ecx
+	jne	die
 	push	$0x55aa55aa
-	popl	%ebx
-	cmpl	$0x55aa55aa, %ebx
-	je	stack_ok
-
-no_stack:
-	/* indicate (lack of) progress */
-	movw	$0x82, %ax
-	movl	$.progress1a, %ebp
-	jmp	show_boot_progress_asm
-.progress1a:
-	jmp die
-
-
-stack_ok:
-	/* indicate progress */
-	movw	$0x03, %ax
-	movl	$.progress2, %ebp
-	jmp	show_boot_progress_asm
-.progress2:
+	popl	%ecx
+	cmpl	$0x55aa55aa, %ecx
+	jne	die
 
 	wbinvd
 
-	/* Get upper memory limit */
-	movl %esp, %ecx
-	subl $CONFIG_SYS_STACK_SIZE, %ecx
+	/* Set the upper memory limit parameter */
+	subl	$CONFIG_SYS_STACK_SIZE, %eax
+
+	/* Reserve space for global data */
+	subl	$(GD_SIZE * 4), %eax
 
-	/* Create a Stack Frame */
-	pushl %ebp
-	movl %esp, %ebp
+	/* %eax points to the global data structure */
+	movl	%esp, (GD_RAM_SIZE * 4)(%eax)
+	movl	%ebx, (GD_FLAGS * 4)(%eax)
 
-	/* stack_limit parameter */
-	pushl	%ecx
 	call	board_init_f	/* Enter, U-boot! */
 
 	/* indicate (lack of) progress */
 	movw	$0x85, %ax
-	movl	$.progress4a, %ebp
-	jmp	show_boot_progress_asm
-.progress4a:
-
 die:	hlt
 	jmp	die
 	hlt
+
+blank_idt_ptr:
+	.word	0		/* limit */
+	.long	0		/* base */