xref: /openbmc/u-boot/arch/arc/lib/start.S (revision 4549e789)
1/* SPDX-License-Identifier: GPL-2.0+ */
2/*
3 * Copyright (C) 2013-2014 Synopsys, Inc. All rights reserved.
4 */
5
6#include <asm-offsets.h>
7#include <config.h>
8#include <linux/linkage.h>
9#include <asm/arcregs.h>
10
11ENTRY(_start)
12	/* Setup interrupt vector base that matches "__text_start" */
13	sr	__ivt_start, [ARC_AUX_INTR_VEC_BASE]
14
15	; Disable/enable I-cache according to configuration
16	lr	r5, [ARC_BCR_IC_BUILD]
17	breq	r5, 0, 1f		; I$ doesn't exist
18	lr	r5, [ARC_AUX_IC_CTRL]
19#ifndef CONFIG_SYS_ICACHE_OFF
20	bclr	r5, r5, 0		; 0 - Enable, 1 is Disable
21#else
22	bset	r5, r5, 0		; I$ exists, but is not used
23#endif
24	sr	r5, [ARC_AUX_IC_CTRL]
25
26	mov	r5, 1
27	sr	r5, [ARC_AUX_IC_IVIC]
28	; As per ARC HS databook (see chapter 5.3.3.2)
29	; it is required to add 3 NOPs after each write to IC_IVIC.
30	nop
31	nop
32	nop
33
341:
35	; Disable/enable D-cache according to configuration
36	lr	r5, [ARC_BCR_DC_BUILD]
37	breq	r5, 0, 1f		; D$ doesn't exist
38	lr	r5, [ARC_AUX_DC_CTRL]
39	bclr	r5, r5, 6		; Invalidate (discard w/o wback)
40#ifndef CONFIG_SYS_DCACHE_OFF
41	bclr	r5, r5, 0		; Enable (+Inv)
42#else
43	bset	r5, r5, 0		; Disable (+Inv)
44#endif
45	sr	r5, [ARC_AUX_DC_CTRL]
46
47	mov	r5, 1
48	sr	r5, [ARC_AUX_DC_IVDC]
49
50
511:
52#ifdef CONFIG_ISA_ARCV2
53	; Disable System-Level Cache (SLC)
54	lr	r5, [ARC_BCR_SLC]
55	breq	r5, 0, 1f		; SLC doesn't exist
56	lr	r5, [ARC_AUX_SLC_CTRL]
57	bclr	r5, r5, 6		; Invalidate (discard w/o wback)
58	bclr	r5, r5, 0		; Enable (+Inv)
59	sr	r5, [ARC_AUX_SLC_CTRL]
60
611:
62#endif
63
64	/* Establish C runtime stack and frame */
65	mov	%sp, CONFIG_SYS_INIT_SP_ADDR
66	mov	%fp, %sp
67
68	/* Allocate reserved area from current top of stack */
69	mov	%r0, %sp
70	bl	board_init_f_alloc_reserve
71	/* Set stack below reserved area, adjust frame pointer accordingly */
72	mov	%sp, %r0
73	mov	%fp, %sp
74
75	/* Initialize reserved area - note: r0 already contains address */
76	bl	board_init_f_init_reserve
77
78	/* Zero the one and only argument of "board_init_f" */
79	mov_s	%r0, 0
80	bl	board_init_f
81
82	/* We only get here if relocation is disabled by GD_FLG_SKIP_RELOC */
83	/* Make sure we don't lose GD overwritten by zero new GD */
84	mov	%r0, %r25
85	mov	%r1, 0
86	bl	board_init_r
87ENDPROC(_start)
88
89/*
90 * void board_init_f_r_trampoline(stack-pointer address)
91 *
92 * This "function" does not return, instead it continues in RAM
93 * after relocating the monitor code.
94 *
95 * r0 = new stack-pointer
96 */
97ENTRY(board_init_f_r_trampoline)
98	/* Set up the stack- and frame-pointers */
99	mov	%sp, %r0
100	mov	%fp, %sp
101
102	/* Update position of intterupt vector table */
103	lr	%r0, [ARC_AUX_INTR_VEC_BASE]
104	ld	%r1, [%r25, GD_RELOC_OFF]
105	add	%r0, %r0, %r1
106	sr	%r0, [ARC_AUX_INTR_VEC_BASE]
107
108	/* Re-enter U-Boot by calling board_init_f_r */
109	j	board_init_f_r
110ENDPROC(board_init_f_r_trampoline)
111