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
|
/*
* (C) Copyright 2007-2008
* Stelian Pop <stelian@popies.net>
* Lead Tech Design <www.leadtechdesign.com>
*
* (C) Copyright 2013
* Bo Shen <voice.shen@atmel.com>
*
* See file CREDITS for list of people who contributed to this
* project.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
#include <common.h>
#include <asm/io.h>
#include <asm/arch/hardware.h>
#include <asm/arch/at91_pit.h>
#include <asm/arch/at91_pmc.h>
#include <asm/arch/clk.h>
#include <div64.h>
#if !defined(CONFIG_AT91FAMILY)
# error You need to define CONFIG_AT91FAMILY in your board config!
#endif
DECLARE_GLOBAL_DATA_PTR;
/*
* We're using the SAMA5D3x PITC in 32 bit mode, by
* setting the 20 bit counter period to its maximum (0xfffff).
* (See the relevant data sheets to understand that this really works)
*
* We do also mimic the typical powerpc way of incrementing
* two 32 bit registers called tbl and tbu.
*
* Those registers increment at 1/16 the main clock rate.
*/
#define TIMER_LOAD_VAL 0xfffff
static inline unsigned long long tick_to_time(unsigned long long tick)
{
tick *= CONFIG_SYS_HZ;
do_div(tick, gd->arch.timer_rate_hz);
return tick;
}
static inline unsigned long long usec_to_tick(unsigned long long usec)
{
usec *= gd->arch.timer_rate_hz;
do_div(usec, 1000000);
return usec;
}
/*
* Use the PITC in full 32 bit incrementing mode
*/
int timer_init(void)
{
at91_pit_t *pit = (at91_pit_t *)ATMEL_BASE_PIT;
/* Enable PITC Clock */
at91_periph_clk_enable(ATMEL_ID_SYS);
/* Enable PITC */
writel(TIMER_LOAD_VAL | AT91_PIT_MR_EN , &pit->mr);
gd->arch.timer_rate_hz = gd->arch.mck_rate_hz / 16;
gd->arch.tbu = 0;
gd->arch.tbl = 0;
return 0;
}
/*
* Get the current 64 bit timer tick count
*/
unsigned long long get_ticks(void)
{
at91_pit_t *pit = (at91_pit_t *)ATMEL_BASE_PIT;
ulong now = readl(&pit->piir);
/* increment tbu if tbl has rolled over */
if (now < gd->arch.tbl)
gd->arch.tbu++;
gd->arch.tbl = now;
return (((unsigned long long)gd->arch.tbu) << 32) | gd->arch.tbl;
}
void __udelay(unsigned long usec)
{
unsigned long long start;
ulong tmo;
start = get_ticks(); /* get current timestamp */
tmo = usec_to_tick(usec); /* convert usecs to ticks */
while ((get_ticks() - start) < tmo)
; /* loop till time has passed */
}
/*
* get_timer(base) can be used to check for timeouts or
* to measure elasped time relative to an event:
*
* ulong start_time = get_timer(0) sets start_time to the current
* time value.
* get_timer(start_time) returns the time elapsed since then.
*
* The time is used in CONFIG_SYS_HZ units!
*/
ulong get_timer(ulong base)
{
return tick_to_time(get_ticks()) - base;
}
/*
* Return the number of timer ticks per second.
*/
ulong get_tbclk(void)
{
return gd->arch.timer_rate_hz;
}
|
