1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * (C) Copyright 2002
4 * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
5 * Marius Groeger <mgroeger@sysgo.de>
6 *
7 * (C) Copyright 2002
8 * David Mueller, ELSOFT AG, <d.mueller@elsoft.ch>
9 *
10 * (C) Copyright 2003
11 * Texas Instruments, <www.ti.com>
12 * Kshitij Gupta <Kshitij@ti.com>
13 *
14 * (C) Copyright 2004
15 * ARM Ltd.
16 * Philippe Robin, <philippe.robin@arm.com>
17 */
18
19 #include <common.h>
20 #include <div64.h>
21 #include <time.h>
22
23 #ifdef CONFIG_ARCH_CINTEGRATOR
24 #define DIV_CLOCK_INIT 1
25 #define TIMER_LOAD_VAL 0xFFFFFFFFL
26 #else
27 #define DIV_CLOCK_INIT 256
28 #define TIMER_LOAD_VAL 0x0000FFFFL
29 #endif
30 /* The Integrator/CP timer1 is clocked at 1MHz
31 * can be divided by 16 or 256
32 * and can be set up as a 32-bit timer
33 */
34 /* U-Boot expects a 32 bit timer, running at CONFIG_SYS_HZ */
35 /* Keep total timer count to avoid losing decrements < div_timer */
36 static unsigned long long total_count = 0;
37 static unsigned long long lastdec; /* Timer reading at last call */
38 /* Divisor applied to timer clock */
39 static unsigned long long div_clock = DIV_CLOCK_INIT;
40 static unsigned long long div_timer = 1; /* Divisor to convert timer reading
41 * change to U-Boot ticks
42 */
43 /* CONFIG_SYS_HZ = CONFIG_SYS_HZ_CLOCK/(div_clock * div_timer) */
44 static ulong timestamp; /* U-Boot ticks since startup */
45
46 #define READ_TIMER (*(volatile ulong *)(CONFIG_SYS_TIMERBASE+4))
47
48 /* all function return values in U-Boot ticks i.e. (1/CONFIG_SYS_HZ) sec
49 * - unless otherwise stated
50 */
51
52 /* starts up a counter
53 * - the Integrator/CP timer can be set up to issue an interrupt */
timer_init(void)54 int timer_init (void)
55 {
56 /* Load timer with initial value */
57 *(volatile ulong *)(CONFIG_SYS_TIMERBASE + 0) = TIMER_LOAD_VAL;
58 #ifdef CONFIG_ARCH_CINTEGRATOR
59 /* Set timer to be
60 * enabled 1
61 * periodic 1
62 * no interrupts 0
63 * X 0
64 * divider 1 00 == less rounding error
65 * 32 bit 1
66 * wrapping 0
67 */
68 *(volatile ulong *)(CONFIG_SYS_TIMERBASE + 8) = 0x000000C2;
69 #else
70 /* Set timer to be
71 * enabled 1
72 * free-running 0
73 * XX 00
74 * divider 256 10
75 * XX 00
76 */
77 *(volatile ulong *)(CONFIG_SYS_TIMERBASE + 8) = 0x00000088;
78 #endif
79
80 /* init the timestamp */
81 total_count = 0ULL;
82 /* capure current decrementer value */
83 lastdec = READ_TIMER;
84 /* start "advancing" time stamp from 0 */
85 timestamp = 0L;
86
87 div_timer = CONFIG_SYS_HZ_CLOCK;
88 do_div(div_timer, CONFIG_SYS_HZ);
89 do_div(div_timer, div_clock);
90
91 return (0);
92 }
93
94 /*
95 * timer without interrupts
96 */
97
98 /* converts the timer reading to U-Boot ticks */
99 /* the timestamp is the number of ticks since reset */
get_timer_masked(void)100 static ulong get_timer_masked (void)
101 {
102 /* get current count */
103 unsigned long long now = READ_TIMER;
104
105 if(now > lastdec) {
106 /* Must have wrapped */
107 total_count += lastdec + TIMER_LOAD_VAL + 1 - now;
108 } else {
109 total_count += lastdec - now;
110 }
111 lastdec = now;
112
113 /* Reuse "now" */
114 now = total_count;
115 do_div(now, div_timer);
116 timestamp = now;
117
118 return timestamp;
119 }
120
get_timer(ulong base_ticks)121 ulong get_timer (ulong base_ticks)
122 {
123 return get_timer_masked () - base_ticks;
124 }
125
126 /* delay usec useconds */
__udelay(unsigned long usec)127 void __udelay (unsigned long usec)
128 {
129 ulong tmo, tmp;
130
131 /* Convert to U-Boot ticks */
132 tmo = usec * CONFIG_SYS_HZ;
133 tmo /= (1000000L);
134
135 tmp = get_timer_masked(); /* get current timestamp */
136 tmo += tmp; /* form target timestamp */
137
138 while (get_timer_masked () < tmo) {/* loop till event */
139 /*NOP*/;
140 }
141 }
142
143 /*
144 * This function is derived from PowerPC code (read timebase as long long).
145 * On ARM it just returns the timer value.
146 */
get_ticks(void)147 unsigned long long get_ticks(void)
148 {
149 return get_timer(0);
150 }
151
152 /*
153 * Return the timebase clock frequency
154 * i.e. how often the timer decrements
155 */
get_tbclk(void)156 ulong get_tbclk (void)
157 {
158 unsigned long long tmp = CONFIG_SYS_HZ_CLOCK;
159
160 do_div(tmp, div_clock);
161
162 return tmp;
163 }
164