xref: /openbmc/u-boot/arch/arc/lib/start.S (revision 274bced8)
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
271:
28	; Disable/enable D-cache according to configuration
29	lr	r5, [ARC_BCR_DC_BUILD]
30	breq	r5, 0, 1f		; D$ doesn't exist
31	lr	r5, [ARC_AUX_DC_CTRL]
32	bclr	r5, r5, 6		; Invalidate (discard w/o wback)
33#ifndef CONFIG_SYS_DCACHE_OFF
34	bclr	r5, r5, 0		; Enable (+Inv)
35#else
36	bset	r5, r5, 0		; Disable (+Inv)
37#endif
38	sr	r5, [ARC_AUX_DC_CTRL]
39
401:
41#ifdef CONFIG_ISA_ARCV2
42	; Disable System-Level Cache (SLC)
43	lr	r5, [ARC_BCR_SLC]
44	breq	r5, 0, 1f		; SLC doesn't exist
45	lr	r5, [ARC_AUX_SLC_CTRL]
46	bclr	r5, r5, 6		; Invalidate (discard w/o wback)
47	bclr	r5, r5, 0		; Enable (+Inv)
48	sr	r5, [ARC_AUX_SLC_CTRL]
49
501:
51#endif
52
53	/* Establish C runtime stack and frame */
54	mov	%sp, CONFIG_SYS_INIT_SP_ADDR
55	mov	%fp, %sp
56
57	/* Allocate reserved area from current top of stack */
58	mov	%r0, %sp
59	bl	board_init_f_alloc_reserve
60	/* Set stack below reserved area, adjust frame pointer accordingly */
61	mov	%sp, %r0
62	mov	%fp, %sp
63
64	/* Initialize reserved area - note: r0 already contains address */
65	bl	board_init_f_init_reserve
66
67	/* Zero the one and only argument of "board_init_f" */
68	mov_s	%r0, 0
69	j	board_init_f
70ENDPROC(_start)
71
72/*
73 * void board_init_f_r_trampoline(stack-pointer address)
74 *
75 * This "function" does not return, instead it continues in RAM
76 * after relocating the monitor code.
77 *
78 * r0 = new stack-pointer
79 */
80ENTRY(board_init_f_r_trampoline)
81	/* Set up the stack- and frame-pointers */
82	mov	%sp, %r0
83	mov	%fp, %sp
84
85	/* Update position of intterupt vector table */
86	lr	%r0, [ARC_AUX_INTR_VEC_BASE]
87	ld	%r1, [%r25, GD_RELOC_OFF]
88	add	%r0, %r0, %r1
89	sr	%r0, [ARC_AUX_INTR_VEC_BASE]
90
91	/* Re-enter U-Boot by calling board_init_f_r */
92	j	board_init_f_r
93ENDPROC(board_init_f_r_trampoline)
94