[thirdparty/u-boot.git] / arch / x86 / cpu / start.S

/*
 *  U-boot - x86 Startup Code
 *
 * (C) Copyright 2008-2011
 * Graeme Russ, <graeme.russ@gmail.com>
 *
 * (C) Copyright 2002
 * Daniel Engström, Omicron Ceti AB, <daniel@omicron.se>
 *
 * SPDX-License-Identifier:	GPL-2.0+
 */

#include <config.h>
#include <version.h>
#include <asm/global_data.h>
#include <asm/processor.h>
#include <asm/processor-flags.h>
#include <generated/generic-asm-offsets.h>

.section .text
.code32
.globl _start
.type _start, @function
.globl _x86boot_start
_x86boot_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 off cache (this might require a 486-class CPU) */
	movl	%cr0, %eax
	orl	$(X86_CR0_NW | X86_CR0_CD), %eax
	movl	%eax, %cr0
	wbinvd

	/* Tell 32-bit code it is being entered from an in-RAM copy */
	movw	$GD_FLG_WARM_BOOT, %bx
	jmp	1f
_start:
	/*
	 * This is the 32-bit cold-reset entry point. Initialize %bx to 0
	 * in case we're preceeded by some sort of boot stub.
	 */
	movw	$GD_FLG_COLD_BOOT, %bx
1:

	/* Load the segement registes to match the gdt loaded in start16.S */
	movl	$(X86_GDT_ENTRY_32BIT_DS * X86_GDT_ENTRY_SIZE), %eax
	movw	%ax, %fs
	movw	%ax, %ds
	movw	%ax, %gs
	movw	%ax, %es
	movw	%ax, %ss

	/* Clear the interrupt vectors */
	lidt	blank_idt_ptr

	/* Early platform init (setup gpio, etc ) */
	jmp	early_board_init
.globl early_board_init_ret
early_board_init_ret:

	/* Initialise Cache-As-RAM */
	jmp	car_init
.globl car_init_ret
car_init_ret:
	/*
	 * We now have CONFIG_SYS_CAR_SIZE bytes of Cache-As-RAM (or SRAM,
	 * or fully initialised SDRAM - we really don't care which)
	 * starting at CONFIG_SYS_CAR_ADDR to be used as a temporary stack
	 */

	/* Stack grows down from top of CAR */
	movl	$(CONFIG_SYS_CAR_ADDR + CONFIG_SYS_CAR_SIZE), %esp

	/* Reserve space on stack for global data */
	subl	$GENERATED_GBL_DATA_SIZE, %esp

	/* Align global data to 16-byte boundary */
	andl	$0xfffffff0, %esp

	/* Setup first parameter to setup_gdt */
	movl	%esp, %eax

	/* Reserve space for global descriptor table */
	subl	$X86_GDT_SIZE, %esp

	/* Align temporary global descriptor table to 16-byte boundary */
	andl	$0xfffffff0, %esp

	/* Set second parameter to setup_gdt */
	movl	%esp, %edx

	/* Setup global descriptor table so gd->xyz works */
	call	setup_gdt

	/* Set parameter to board_init_f() to boot flags */
	xorl	%eax, %eax
	movw	%bx, %ax

	/* Enter, U-boot! */
	call	board_init_f

	/* indicate (lack of) progress */
	movw	$0x85, %ax
	jmp	die

.globl board_init_f_r_trampoline
.type board_init_f_r_trampoline, @function
board_init_f_r_trampoline:
	/*
	 * 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 new stack
	 */

	/* Stack grows down from top of SDRAM */
	movl	%eax, %esp

	/* Reserve space on stack for global data */
	subl	$GENERATED_GBL_DATA_SIZE, %esp

	/* Align global data to 16-byte boundary */
	andl	$0xfffffff0, %esp

	/* Setup first parameter to memcpy (and setup_gdt) */
	movl	%esp, %eax

	/* Setup second parameter to memcpy */
	fs movl 0, %edx

	/* Set third parameter to memcpy */
	movl	$GENERATED_GBL_DATA_SIZE, %ecx

	/* Copy global data from CAR to SDRAM stack */
	call	memcpy

	/* Reserve space for global descriptor table */
	subl	$X86_GDT_SIZE, %esp

	/* Align global descriptor table to 16-byte boundary */
	andl	$0xfffffff0, %esp

	/* Set second parameter to setup_gdt */
	movl	%esp, %edx

	/* Setup global descriptor table so gd->xyz works */
	call	setup_gdt

	/* Re-enter U-Boot by calling board_init_f_r */
	call	board_init_f_r

die:
	hlt
	jmp	die
	hlt

blank_idt_ptr:
	.word	0		/* limit */
	.long	0		/* base */

	.p2align	2	/* force 4-byte alignment */

multiboot_header:
	/* magic */
	.long	0x1BADB002
	/* flags */
	.long	(1 << 16)
	/* checksum */
	.long	-0x1BADB002 - (1 << 16)
	/* header addr */
	.long	multiboot_header - _x86boot_start + CONFIG_SYS_TEXT_BASE
	/* load addr */
	.long	CONFIG_SYS_TEXT_BASE
	/* load end addr */
	.long	0
	/* bss end addr */
	.long	0
	/* entry addr */
	.long	CONFIG_SYS_TEXT_BASE
Commit	Line	Data
2262cfee	1	/*
fea25720	2	* U-boot - x86 Startup Code
2262cfee	3	*
dbf7115a GR	4	* (C) Copyright 2008-2011
	5	* Graeme Russ, <graeme.russ@gmail.com>
	6	*
	7	* (C) Copyright 2002
fa82f871	8	* Daniel Engström, Omicron Ceti AB, <daniel@omicron.se>
2262cfee	9	*
1a459660	10	* SPDX-License-Identifier: GPL-2.0+
2262cfee WD	11	*/
2262cfee WD	12
2262cfee WD	13	#include <config.h>
2262cfee WD	14	#include <version.h>
161b3589	15	#include <asm/global_data.h>
109ad143	16	#include <asm/processor.h>
0c24c9cc	17	#include <asm/processor-flags.h>
9e6c572f	18	#include <generated/generic-asm-offsets.h>
2262cfee	19
2262cfee WD	20	.section .text
	21	.code32
	22	.globl _start
8bde7f77	23	.type _start, @function
fea25720 GR	24	.globl _x86boot_start
fea25720 GR	25	_x86boot_start:
077e1958 GR	26	/*
	27	* This is the fail safe 32-bit bootstrap entry point. The
	28	* following code is not executed from a cold-reset (actually, a
	29	* lot of it is, but from real-mode after cold reset. It is
	30	* repeated here to put the board into a state as close to cold
	31	* reset as necessary)
	32	*/
	33	cli
	34	cld
	35
2f0e0cd2	36	/* Turn off cache (this might require a 486-class CPU) */
077e1958	37	movl %cr0, %eax
0c24c9cc	38	orl $(X86_CR0_NW \| X86_CR0_CD), %eax
077e1958 GR	39	movl %eax, %cr0
	40	wbinvd
	41
91d82a29 GB	42	/* Tell 32-bit code it is being entered from an in-RAM copy */
	43	movw $GD_FLG_WARM_BOOT, %bx
	44	jmp 1f
8bde7f77	45	_start:
91d82a29 GB	46	/*
	47	* This is the 32-bit cold-reset entry point. Initialize %bx to 0
	48	* in case we're preceeded by some sort of boot stub.
	49	*/
	50	movw $GD_FLG_COLD_BOOT, %bx
	51	1:
077e1958	52
dbf7115a	53	/* Load the segement registes to match the gdt loaded in start16.S */
109ad143	54	movl $(X86_GDT_ENTRY_32BIT_DS * X86_GDT_ENTRY_SIZE), %eax
8ffb2e8f GR	55	movw %ax, %fs
	56	movw %ax, %ds
	57	movw %ax, %gs
	58	movw %ax, %es
	59	movw %ax, %ss
8bde7f77	60
16263087	61	/* Clear the interrupt vectors */
077e1958 GR	62	lidt blank_idt_ptr
077e1958 GR	63
2262cfee	64	/* Early platform init (setup gpio, etc ) */
2262cfee	65	jmp early_board_init
88fa0a6e	66	.globl early_board_init_ret
2262cfee	67	early_board_init_ret:
8bde7f77	68
ed4cba79 GR	69	/* Initialise Cache-As-RAM */
	70	jmp car_init
	71	.globl car_init_ret
	72	car_init_ret:
	73	/*
	74	* We now have CONFIG_SYS_CAR_SIZE bytes of Cache-As-RAM (or SRAM,
	75	* or fully initialised SDRAM - we really don't care which)
	76	* starting at CONFIG_SYS_CAR_ADDR to be used as a temporary stack
	77	*/
759598f8	78
8d61625d GR	79	/* Stack grows down from top of CAR */
	80	movl $(CONFIG_SYS_CAR_ADDR + CONFIG_SYS_CAR_SIZE), %esp
	81
	82	/* Reserve space on stack for global data */
	83	subl $GENERATED_GBL_DATA_SIZE, %esp
	84
	85	/* Align global data to 16-byte boundary */
	86	andl $0xfffffff0, %esp
	87
	88	/* Setup first parameter to setup_gdt */
	89	movl %esp, %eax
	90
	91	/* Reserve space for global descriptor table */
	92	subl $X86_GDT_SIZE, %esp
	93
	94	/* Align temporary global descriptor table to 16-byte boundary */
	95	andl $0xfffffff0, %esp
	96
	97	/* Set second parameter to setup_gdt */
	98	movl %esp, %edx
	99
8d61625d GR	100	/* Setup global descriptor table so gd->xyz works */
8d61625d GR	101	call setup_gdt
9e6c572f	102
96cd6642	103	/* Set parameter to board_init_f() to boot flags */
dbf7115a GR	104	xorl %eax, %eax
dbf7115a GR	105	movw %bx, %ax
161b3589	106
dbf7115a GR	107	/* Enter, U-boot! */
dbf7115a GR	108	call board_init_f
2262cfee WD	109
2262cfee WD	110	/* indicate (lack of) progress */
8bde7f77	111	movw $0x85, %ax
fb002908 GR	112	jmp die
fb002908 GR	113
f48dd6fc GR	114	.globl board_init_f_r_trampoline
	115	.type board_init_f_r_trampoline, @function
	116	board_init_f_r_trampoline:
fb002908 GR	117	/*
	118	* SDRAM has been initialised, U-Boot code has been copied into
	119	* RAM, BSS has been cleared and relocation adjustments have been
	120	* made. It is now time to jump into the in-RAM copy of U-Boot
	121	*
f48dd6fc	122	* %eax = Address of top of new stack
fb002908 GR	123	*/
fb002908 GR	124
8d61625d	125	/* Stack grows down from top of SDRAM */
fb002908 GR	126	movl %eax, %esp
fb002908 GR	127
8d61625d GR	128	/* Reserve space on stack for global data */
	129	subl $GENERATED_GBL_DATA_SIZE, %esp
	130
	131	/* Align global data to 16-byte boundary */
	132	andl $0xfffffff0, %esp
	133
	134	/* Setup first parameter to memcpy (and setup_gdt) */
	135	movl %esp, %eax
	136
	137	/* Setup second parameter to memcpy */
	138	fs movl 0, %edx
	139
	140	/* Set third parameter to memcpy */
	141	movl $GENERATED_GBL_DATA_SIZE, %ecx
	142
	143	/* Copy global data from CAR to SDRAM stack */
	144	call memcpy
	145
	146	/* Reserve space for global descriptor table */
	147	subl $X86_GDT_SIZE, %esp
	148
	149	/* Align global descriptor table to 16-byte boundary */
	150	andl $0xfffffff0, %esp
	151
	152	/* Set second parameter to setup_gdt */
	153	movl %esp, %edx
	154
8d61625d GR	155	/* Setup global descriptor table so gd->xyz works */
	156	call setup_gdt
	157
f48dd6fc GR	158	/* Re-enter U-Boot by calling board_init_f_r */
f48dd6fc GR	159	call board_init_f_r
fb002908	160
2f0e0cd2 GR	161	die:
2f0e0cd2 GR	162	hlt
2262cfee	163	jmp die
8bde7f77	164	hlt
077e1958 GR	165
	166	blank_idt_ptr:
	167	.word 0 /* limit */
	168	.long 0 /* base */
a206cc23 GR	169
	170	.p2align 2 /* force 4-byte alignment */
	171
	172	multiboot_header:
	173	/* magic */
	174	.long 0x1BADB002
	175	/* flags */
	176	.long (1 << 16)
	177	/* checksum */
	178	.long -0x1BADB002 - (1 << 16)
	179	/* header addr */
	180	.long multiboot_header - _x86boot_start + CONFIG_SYS_TEXT_BASE
	181	/* load addr */
	182	.long CONFIG_SYS_TEXT_BASE
	183	/* load end addr */
	184	.long 0
	185	/* bss end addr */
	186	.long 0
	187	/* entry addr */
	188	.long CONFIG_SYS_TEXT_BASE