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
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
|
/****************************************************************************
* arch/arm/src/sam34/sam_timerisr.c
*
* Copyright (C) 2010, 2013 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdint.h>
#include <time.h>
#include <debug.h>
#include <nuttx/arch.h>
#include <arch/board/board.h>
#include "nvic.h"
#include "clock_internal.h"
#include "up_internal.h"
#include "up_arch.h"
#include "chip.h"
/****************************************************************************
* Definitions
****************************************************************************/
/* Select MCU-specific settings
*
* For the SAM3U, Systick is driven by the main clock.
* For the SAM4L, Systick is driven by the CPU clock which is just the main
* clock divided down.
*/
#if defined(CONFIG_ARCH_CHIP_SAM3U)
# define SAM_SYSTICK_CLOCK BOARD_MCK_FREQUENCY /* Frequency of the main clock */
#elif defined(CONFIG_ARCH_CHIP_SAM4L) || defined(CONFIG_ARCH_CHIP_SAM4S)
# define SAM_SYSTICK_CLOCK BOARD_CPU_FREQUENCY /* CPU frequency */
#else
# error Unrecognized SAM architecture
#endif
/* The desired timer interrupt frequency is provided by the definition
* CLK_TCK (see include/time.h). CLK_TCK defines the desired number of
* system clock ticks per second. That value is a user configurable setting
* that defaults to 100 (100 ticks per second = 10 MS interval).
*
* The SAM3U feeds the Cortex System Timer (SysTick) with the MCK clock or
* the MCK clock divided by 8, configurable with the CLKSOURCE bit in the
* SysTick Control and Status register.
*/
#undef CONFIG_SAM34_SYSTICK_HCLKd8 /* Power up default is MCK, not MCK/8 */
#if CONFIG_SAM34_SYSTICK_HCLKd8
# define SYSTICK_RELOAD ((SAM_SYSTICK_CLOCK / 8 / CLK_TCK) - 1)
#else
# define SYSTICK_RELOAD ((SAM_SYSTICK_CLOCK / CLK_TCK) - 1)
#endif
/* The size of the reload field is 24 bits. Verify that the reload value
* will fit in the reload register.
*/
#if SYSTICK_RELOAD > 0x00ffffff
# error SYSTICK_RELOAD exceeds the range of the RELOAD register
#endif
/****************************************************************************
* Private Types
****************************************************************************/
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/****************************************************************************
* Global Functions
****************************************************************************/
/****************************************************************************
* Function: up_timerisr
*
* Description:
* The timer ISR will perform a variety of services for various portions
* of the systems.
*
****************************************************************************/
int up_timerisr(int irq, uint32_t *regs)
{
/* Process timer interrupt */
sched_process_timer();
return 0;
}
/****************************************************************************
* Function: up_timerinit
*
* Description:
* This function is called during start-up to initialize
* the timer interrupt.
*
****************************************************************************/
void up_timerinit(void)
{
uint32_t regval;
/* Set the SysTick interrupt to the default priority */
regval = getreg32(NVIC_SYSH12_15_PRIORITY);
regval &= ~NVIC_SYSH_PRIORITY_PR15_MASK;
regval |= (NVIC_SYSH_PRIORITY_DEFAULT << NVIC_SYSH_PRIORITY_PR15_SHIFT);
putreg32(regval, NVIC_SYSH12_15_PRIORITY);
/* Make sure that the SYSTICK clock source is set correctly */
#if 0 /* Does not work. Comes up with HCLK source and I can't change it */
regval = getreg32(NVIC_SYSTICK_CTRL);
#if CONFIG_SAM34_SYSTICK_HCLKd8
regval &= ~NVIC_SYSTICK_CTRL_CLKSOURCE;
#else
regval |= NVIC_SYSTICK_CTRL_CLKSOURCE;
#endif
putreg32(regval, NVIC_SYSTICK_CTRL);
#endif
/* Configure SysTick to interrupt at the requested rate */
putreg32(SYSTICK_RELOAD, NVIC_SYSTICK_RELOAD);
/* Attach the timer interrupt vector */
(void)irq_attach(SAM_IRQ_SYSTICK, (xcpt_t)up_timerisr);
/* Enable SysTick interrupts */
putreg32((NVIC_SYSTICK_CTRL_CLKSOURCE|NVIC_SYSTICK_CTRL_TICKINT|NVIC_SYSTICK_CTRL_ENABLE), NVIC_SYSTICK_CTRL);
/* And enable the timer interrupt */
up_enable_irq(SAM_IRQ_SYSTICK);
}
|
