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
|
/*
* Copyright (c) 2014 embedded brains GmbH. All rights reserved.
*
* embedded brains GmbH
* Dornierstr. 4
* 82178 Puchheim
* Germany
* <rtems@embedded-brains.de>
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.com/license/LICENSE.
*/
#include <leon.h>
#include <rtems/counter.h>
static volatile struct gptimer_regs *adev_to_gpt(struct ambapp_dev *adev)
{
return (volatile struct gptimer_regs *) DEV_TO_APB(adev)->start;
}
static CPU_Counter_ticks free_counter_difference(
CPU_Counter_ticks second,
CPU_Counter_ticks first
)
{
return first - second;
}
static CPU_Counter_ticks clock_counter_difference(
CPU_Counter_ticks second,
CPU_Counter_ticks first
)
{
CPU_Counter_ticks period = rtems_configuration_get_microseconds_per_tick();
return (first + period - second) % period;
}
static void gpt_counter_initialize(
volatile struct gptimer_regs *gpt,
size_t timer_index,
uint32_t frequency,
SPARC_Counter_difference counter_difference
)
{
_SPARC_Counter_initialize(
(volatile const uint32_t *) &gpt->timer[timer_index].value,
counter_difference
);
rtems_counter_initialize_converter(frequency);
}
void leon3_cpu_counter_initialize(void)
{
struct ambapp_dev *adev;
adev = (void *) ambapp_for_each(
&ambapp_plb,
OPTIONS_ALL | OPTIONS_APB_SLVS,
VENDOR_GAISLER,
GAISLER_GPTIMER,
ambapp_find_by_idx,
NULL
);
if (adev != NULL) {
volatile struct gptimer_regs *gpt = adev_to_gpt(adev);
unsigned prescaler = gpt->scaler_reload + 1;
/* Assume that GRMON initialized the first GPTIMER to 1MHz */
uint32_t frequency = 1000000;
uint32_t max_frequency = frequency * prescaler;
int idx = 1;
adev = (void *) ambapp_for_each(
&ambapp_plb,
OPTIONS_ALL | OPTIONS_APB_SLVS,
VENDOR_GAISLER,
GAISLER_GPTIMER,
ambapp_find_by_idx,
&idx
);
if (adev != NULL) {
/* Use the second GPTIMER if available */
unsigned min_prescaler = 8;
gpt = adev_to_gpt(adev);
gpt->scaler_reload = min_prescaler - 1;
gpt->timer[0].reload = 0xffffffff;
gpt->timer[0].ctrl = LEON3_GPTIMER_EN | LEON3_GPTIMER_RL
| LEON3_GPTIMER_LD;
frequency = max_frequency / min_prescaler;
gpt_counter_initialize(gpt, 0, frequency, free_counter_difference);
} else {
/* Fall back to the first GPTIMER */
gpt_counter_initialize(
gpt,
LEON3_CLOCK_INDEX,
frequency,
clock_counter_difference
);
}
}
}
|
