Newer
Older
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
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
/****************************************************************************
* configs/grxbetastamp/src/bootloader.c
*
* Copyright (C) 2016 Sebastien Lorquet. All rights reserved.
* Author: Sebastien Lorquet <sebastien@lorquet.fr>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/************************************************************************************
* Pre-processor Definitions
************************************************************************************/
#define BOOT_STACKSIZE (16 * 1024)
#define BOOT_STACK ((unsigned)&_ebss+ BOOT_STACKSIZE-4)
#define BOOT_PERIPHERAL_INTERRUPTS 16
/****************************************************************************
* Public Functions
****************************************************************************/
/* Chip-specific entrypoint */
extern void __boot_start(void);
/* Common exception entrypoint */
extern void __boot_exception_common(void);
/************************************************************************************
* Public data
************************************************************************************/
/* Provided by the linker script to indicate the end of the BSS and start of text */
extern char _ebss;
extern char _stext;
/* The v7m vector table consists of an array of function pointers, with the first
* slot (vector zero) used to hold the initial stack pointer.
*
* As all exceptions (interrupts) are routed via exception_common, we just need to
* fill this array with pointers to it.
*
* Note that the [ ... ] designated initialiser is a GCC extension.
*/
unsigned __boot_vectors[] __attribute__((section(".boot.vectors"))) =
{
BOOT_STACK, /* Initial stack */
(unsigned)&__boot_start, /* Reset exception handler */
/* Vectors 2 - n point directly at the generic handler */
[2 ... (15 + BOOT_PERIPHERAL_INTERRUPTS)] = (unsigned)&__boot_exception_common
};
#define BOOTCODE __attribute__(( section(".boot.text") ))
BOOTCODE __attribute__((naked)) void __boot_app(void)
{
__asm__ __volatile__ ("\t"
/* load SP (from 08004000) */
"movw r0, #0x4000 \n\t"
"movt r0, #0x0800 \n\t"
"ldr sp, [r0] \n\t"
/* load LR (from 08004004) */
"movw r0, #0x4004 \n\t"
"movt r0, #0x0800 \n\t"
"ldr r0, [r0] \n\t"
"mov lr, r0 \n\t"
/* setup VTOR (at E000ED08) to remap vectors*/
"movw r0, #0xED08 /*adr lo*/ \n\t"
"movt r0, #0xE000 /*adr hi*/ \n\t"
"movw r1, #0x4000 /*val lo*/ \n\t"
"movt r1, #0x0800 /*val hi*/ \n\t"
"str r1, [r0] /*store value at address*/ \n\t"
"bx lr /*take the jump*/ \n"
);
}
BOOTCODE void __boot_start(void)
{
__boot_app();
while(1);
}
BOOTCODE void __boot_exception_common(void)
{
while(1);
}