xref: /openbmc/u-boot/arch/arc/lib/start.S (revision 85fc970d)
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; ARCompact devices are not supposed to be SMP so master/slave check
14; makes no sense.
15#ifdef CONFIG_ISA_ARCV2
16	; Non-masters will be halted immediately, they might be kicked later
17	; by platform code right before passing control to the Linux kernel
18	; in bootm.c:boot_jump_linux().
19	lr 	r5, [identity]
20	lsr	r5, r5, 8
21	bmsk	r5, r5, 7
22	cmp	r5, 0
23	mov.nz	r0, r5
24	bz	.Lmaster_proceed
25	flag	1
26	nop
27	nop
28	nop
29
30.Lmaster_proceed:
31#endif
32
33	/* Setup interrupt vector base that matches "__text_start" */
34	sr	__ivt_start, [ARC_AUX_INTR_VEC_BASE]
35
36	; Disable/enable I-cache according to configuration
37	lr	r5, [ARC_BCR_IC_BUILD]
38	breq	r5, 0, 1f		; I$ doesn't exist
39	lr	r5, [ARC_AUX_IC_CTRL]
40#ifndef CONFIG_SYS_ICACHE_OFF
41	bclr	r5, r5, 0		; 0 - Enable, 1 is Disable
42#else
43	bset	r5, r5, 0		; I$ exists, but is not used
44#endif
45	sr	r5, [ARC_AUX_IC_CTRL]
46
471:
48	; Disable/enable D-cache according to configuration
49	lr	r5, [ARC_BCR_DC_BUILD]
50	breq	r5, 0, 1f		; D$ doesn't exist
51	lr	r5, [ARC_AUX_DC_CTRL]
52	bclr	r5, r5, 6		; Invalidate (discard w/o wback)
53#ifndef CONFIG_SYS_DCACHE_OFF
54	bclr	r5, r5, 0		; Enable (+Inv)
55#else
56	bset	r5, r5, 0		; Disable (+Inv)
57#endif
58	sr	r5, [ARC_AUX_DC_CTRL]
59
601:
61#ifdef CONFIG_ISA_ARCV2
62	; Disable System-Level Cache (SLC)
63	lr	r5, [ARC_BCR_SLC]
64	breq	r5, 0, 1f		; SLC doesn't exist
65	lr	r5, [ARC_AUX_SLC_CTRL]
66	bclr	r5, r5, 6		; Invalidate (discard w/o wback)
67	bclr	r5, r5, 0		; Enable (+Inv)
68	sr	r5, [ARC_AUX_SLC_CTRL]
69
701:
71#endif
72
73	/* Establish C runtime stack and frame */
74	mov	%sp, CONFIG_SYS_INIT_SP_ADDR
75	mov	%fp, %sp
76
77	/* Allocate reserved area from current top of stack */
78	mov	%r0, %sp
79	bl	board_init_f_alloc_reserve
80	/* Set stack below reserved area, adjust frame pointer accordingly */
81	mov	%sp, %r0
82	mov	%fp, %sp
83
84	/* Initialize reserved area - note: r0 already contains address */
85	bl	board_init_f_init_reserve
86
87	/* Zero the one and only argument of "board_init_f" */
88	mov_s	%r0, 0
89	j	board_init_f
90ENDPROC(_start)
91
92/*
93 * void board_init_f_r_trampoline(stack-pointer address)
94 *
95 * This "function" does not return, instead it continues in RAM
96 * after relocating the monitor code.
97 *
98 * r0 = new stack-pointer
99 */
100ENTRY(board_init_f_r_trampoline)
101	/* Set up the stack- and frame-pointers */
102	mov	%sp, %r0
103	mov	%fp, %sp
104
105	/* Update position of intterupt vector table */
106	lr	%r0, [ARC_AUX_INTR_VEC_BASE]
107	ld	%r1, [%r25, GD_RELOC_OFF]
108	add	%r0, %r0, %r1
109	sr	%r0, [ARC_AUX_INTR_VEC_BASE]
110
111	/* Re-enter U-Boot by calling board_init_f_r */
112	j	board_init_f_r
113ENDPROC(board_init_f_r_trampoline)
114