xref: /rk3399_rockchip-uboot/arch/arc/lib/start.S (revision 8ee28251d95e237302c7c44929e59a813e147622)
1/*
2 * Copyright (C) 2013-2014 Synopsys, Inc. All rights reserved.
3 *
4 * SPDX-License-Identifier:	GPL-2.0+
5 */
6
7#include <asm-offsets.h>
8#include <config.h>
9#include <linux/linkage.h>
10#include <asm/arcregs.h>
11
12ENTRY(_start)
13	/* Setup interrupt vector base that matches "__text_start" */
14	sr	__ivt_start, [ARC_AUX_INTR_VEC_BASE]
15
16	/* Setup stack pointer */
17	mov	%sp, CONFIG_SYS_INIT_SP_ADDR
18	mov	%fp, %sp
19
20	/* Clear bss */
21	mov	%r0, __bss_start
22	mov	%r1, __bss_end
23
24clear_bss:
25	st.ab	0, [%r0, 4]
26	brlt	%r0, %r1, clear_bss
27
28	/* Zero the one and only argument of "board_init_f" */
29	mov_s	%r0, 0
30	j	board_init_f
31ENDPROC(_start)
32
33/*
34 * void relocate_code (addr_sp, gd, addr_moni)
35 *
36 * This "function" does not return, instead it continues in RAM
37 * after relocating the monitor code.
38 *
39 * r0 = start_addr_sp
40 * r1 = new__gd
41 * r2 = relocaddr
42 */
43ENTRY(relocate_code)
44	/*
45	 * r0-r12 might be clobbered by C functions
46	 * so we use r13-r16 for storage here
47	 */
48	mov	%r13, %r0		/* save addr_sp */
49	mov	%r14, %r1		/* save addr of gd */
50	mov	%r15, %r2		/* save addr of destination */
51
52	mov	%r16, %r2		/* %r9 - relocation offset */
53	sub	%r16, %r16, __image_copy_start
54
55/* Set up the stack */
56stack_setup:
57	mov	%sp, %r13
58	mov	%fp, %sp
59
60/* Check if monitor is loaded right in place for relocation */
61	mov	%r0, __image_copy_start
62	cmp	%r0, %r15		/* skip relocation if code loaded */
63	bz	do_board_init_r		/* in target location already */
64
65/* Copy data (__image_copy_start - __image_copy_end) to new location */
66	mov	%r1, %r15
67	mov	%r2, __image_copy_end
68	sub	%r2, %r2, %r0		/* r3 <- amount of bytes to copy */
69	asr	%r2, %r2, 2		/* r3 <- amount of words to copy */
70	mov	%lp_count, %r2
71	lp	copy_end
72	ld.ab	%r2,[%r0,4]
73	st.ab	%r2,[%r1,4]
74copy_end:
75
76/* Fix relocations related issues */
77	bl	do_elf_reloc_fixups
78#ifndef CONFIG_SYS_ICACHE_OFF
79	bl	invalidate_icache_all
80#endif
81#ifndef CONFIG_SYS_DCACHE_OFF
82	bl	flush_dcache_all
83#endif
84
85/* Update position of intterupt vector table */
86	lr	%r0, [ARC_AUX_INTR_VEC_BASE]	/* Read current position */
87	add	%r0, %r0, %r16			/* Update address */
88	sr	%r0, [ARC_AUX_INTR_VEC_BASE]	/* Write new position */
89
90do_board_init_r:
91/* Prepare for exection of "board_init_r" in relocated monitor */
92	mov	%r2, board_init_r	/* old address of "board_init_r()" */
93	add	%r2, %r2, %r16		/* new address of "board_init_r()" */
94	mov	%r0, %r14		/* 1-st parameter: gd_t */
95	mov	%r1, %r15		/* 2-nd parameter: dest_addr */
96	j	[%r2]
97ENDPROC(relocate_code)
98