/
litex_shead.S
92 lines (67 loc) · 2.41 KB
/
litex_shead.S
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
/****************************************************************************
* arch/risc-v/src/litex/litex_shead.S
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <nuttx/irq.h>
#include "chip.h"
#include "litex_memorymap.h"
#include "riscv_internal.h"
/****************************************************************************
* Public Symbols
****************************************************************************/
/* Imported symbols */
.extern __trap_vec
.section .text
.global __start
/****************************************************************************
* Name: __start
*
* Description:
* Supervisor mode start function.
*
* Input Parameters:
* a0 - hartid
*
****************************************************************************/
__start:
/* Disable all interrupts in sie */
csrw CSR_SIE, zero
csrw CSR_SIP, zero
/* Set the S-mode trap vector */
la t0, __trap_vec
csrw CSR_STVEC, t0
/* Clear sscratch */
csrw CSR_SSCRATCH, zero
csrw CSR_SCAUSE, zero
csrw CSR_SEPC, zero
/* initialize global pointer, global data */
.option push
.option norelax
la gp, __global_pointer$
.option pop
lui sp, %hi(LITEX_IDLESTACK_TOP)
addi sp, sp, %lo(LITEX_IDLESTACK_TOP)
/* Make sure the writes to CSR stick before continuing */
fence
/* Set stack pointer and jump to start */
/*la sp, LITEX_IDLESTACK_TOP*/
j __litex_start