xref: /openbmc/u-boot/arch/arc/lib/start.S (revision 85231c08)
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	; Disable/enable I-cache according to configuration
17	lr	r5, [ARC_BCR_IC_BUILD]
18	breq	r5, 0, 1f		; I$ doesn't exist
19	lr	r5, [ARC_AUX_IC_CTRL]
20#ifndef CONFIG_SYS_ICACHE_OFF
21	bclr	r5, r5, 0		; 0 - Enable, 1 is Disable
22#else
23	bset	r5, r5, 0		; I$ exists, but is not used
24#endif
25	sr	r5, [ARC_AUX_IC_CTRL]
26
27	mov	r5, 1
28	sr	r5, [ARC_AUX_IC_IVIC]
29	; As per ARC HS databook (see chapter 5.3.3.2)
30	; it is required to add 3 NOPs after each write to IC_IVIC.
31	nop
32	nop
33	nop
34
351:
36	; Disable/enable D-cache according to configuration
37	lr	r5, [ARC_BCR_DC_BUILD]
38	breq	r5, 0, 1f		; D$ doesn't exist
39	lr	r5, [ARC_AUX_DC_CTRL]
40	bclr	r5, r5, 6		; Invalidate (discard w/o wback)
41#ifndef CONFIG_SYS_DCACHE_OFF
42	bclr	r5, r5, 0		; Enable (+Inv)
43#else
44	bset	r5, r5, 0		; Disable (+Inv)
45#endif
46	sr	r5, [ARC_AUX_DC_CTRL]
47
48	mov	r5, 1
49	sr	r5, [ARC_AUX_DC_IVDC]
50
51
521:
53#ifdef CONFIG_ISA_ARCV2
54	; Disable System-Level Cache (SLC)
55	lr	r5, [ARC_BCR_SLC]
56	breq	r5, 0, 1f		; SLC doesn't exist
57	lr	r5, [ARC_AUX_SLC_CTRL]
58	bclr	r5, r5, 6		; Invalidate (discard w/o wback)
59	bclr	r5, r5, 0		; Enable (+Inv)
60	sr	r5, [ARC_AUX_SLC_CTRL]
61
621:
63#endif
64
65	/* Establish C runtime stack and frame */
66	mov	%sp, CONFIG_SYS_INIT_SP_ADDR
67	mov	%fp, %sp
68
69	/* Allocate reserved area from current top of stack */
70	mov	%r0, %sp
71	bl	board_init_f_alloc_reserve
72	/* Set stack below reserved area, adjust frame pointer accordingly */
73	mov	%sp, %r0
74	mov	%fp, %sp
75
76	/* Initialize reserved area - note: r0 already contains address */
77	bl	board_init_f_init_reserve
78
79	/* Zero the one and only argument of "board_init_f" */
80	mov_s	%r0, 0
81	bl	board_init_f
82
83	/* We only get here if relocation is disabled by GD_FLG_SKIP_RELOC */
84	/* Make sure we don't lose GD overwritten by zero new GD */
85	mov	%r0, %r25
86	mov	%r1, 0
87	bl	board_init_r
88ENDPROC(_start)
89
90/*
91 * void board_init_f_r_trampoline(stack-pointer address)
92 *
93 * This "function" does not return, instead it continues in RAM
94 * after relocating the monitor code.
95 *
96 * r0 = new stack-pointer
97 */
98ENTRY(board_init_f_r_trampoline)
99	/* Set up the stack- and frame-pointers */
100	mov	%sp, %r0
101	mov	%fp, %sp
102
103	/* Update position of intterupt vector table */
104	lr	%r0, [ARC_AUX_INTR_VEC_BASE]
105	ld	%r1, [%r25, GD_RELOC_OFF]
106	add	%r0, %r0, %r1
107	sr	%r0, [ARC_AUX_INTR_VEC_BASE]
108
109	/* Re-enter U-Boot by calling board_init_f_r */
110	j	board_init_f_r
111ENDPROC(board_init_f_r_trampoline)
112