/*
* 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.
.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) */
+ 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
-
- /* Create a Stack Frame */
- pushl %ebp
- movl %esp, %ebp
+ /* Set the upper memory limit parameter */
+ subl $CONFIG_SYS_STACK_SIZE, %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 */