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 #include <linux/delay.h>
23
24 #ifdef CONFIG_ARCH_CINTEGRATOR
25 #define DIV_CLOCK_INIT 1
26 #define TIMER_LOAD_VAL 0xFFFFFFFFL
27 #else
28 #define DIV_CLOCK_INIT 256
29 #define TIMER_LOAD_VAL 0x0000FFFFL
30 #endif
31 /* The Integrator/CP timer1 is clocked at 1MHz
32 * can be divided by 16 or 256
33 * and can be set up as a 32-bit timer
34 */
35 /* U-Boot expects a 32 bit timer, running at CONFIG_SYS_HZ */
36 /* Keep total timer count to avoid losing decrements < div_timer */
37 static unsigned long long total_count = 0;
38 static unsigned long long lastdec; /* Timer reading at last call */
39 /* Divisor applied to timer clock */
40 static unsigned long long div_clock = DIV_CLOCK_INIT;
41 static unsigned long long div_timer = 1; /* Divisor to convert timer reading
42 * change to U-Boot ticks
43 */
44 /* CONFIG_SYS_HZ = CONFIG_SYS_HZ_CLOCK/(div_clock * div_timer) */
45 static ulong timestamp; /* U-Boot ticks since startup */
46
47 #define READ_TIMER (*(volatile ulong *)(CONFIG_SYS_TIMERBASE+4))
48
49 /* all function return values in U-Boot ticks i.e. (1/CONFIG_SYS_HZ) sec
50 * - unless otherwise stated
51 */
52
53 /* starts up a counter
54 * - the Integrator/CP timer can be set up to issue an interrupt */
timer_init(void)55 int timer_init (void)
56 {
57 /* Load timer with initial value */
58 *(volatile ulong *)(CONFIG_SYS_TIMERBASE + 0) = TIMER_LOAD_VAL;
59 #ifdef CONFIG_ARCH_CINTEGRATOR
60 /* Set timer to be
61 * enabled 1
62 * periodic 1
63 * no interrupts 0
64 * X 0
65 * divider 1 00 == less rounding error
66 * 32 bit 1
67 * wrapping 0
68 */
69 *(volatile ulong *)(CONFIG_SYS_TIMERBASE + 8) = 0x000000C2;
70 #else
71 /* Set timer to be
72 * enabled 1
73 * free-running 0
74 * XX 00
75 * divider 256 10
76 * XX 00
77 */
78 *(volatile ulong *)(CONFIG_SYS_TIMERBASE + 8) = 0x00000088;
79 #endif
80
81 /* init the timestamp */
82 total_count = 0ULL;
83 /* capure current decrementer value */
84 lastdec = READ_TIMER;
85 /* start "advancing" time stamp from 0 */
86 timestamp = 0L;
87
88 div_timer = CONFIG_SYS_HZ_CLOCK;
89 do_div(div_timer, CONFIG_SYS_HZ);
90 do_div(div_timer, div_clock);
91
92 return (0);
93 }
94
95 /*
96 * timer without interrupts
97 */
98
99 /* converts the timer reading to U-Boot ticks */
100 /* the timestamp is the number of ticks since reset */
get_timer_masked(void)101 static ulong get_timer_masked (void)
102 {
103 /* get current count */
104 unsigned long long now = READ_TIMER;
105
106 if(now > lastdec) {
107 /* Must have wrapped */
108 total_count += lastdec + TIMER_LOAD_VAL + 1 - now;
109 } else {
110 total_count += lastdec - now;
111 }
112 lastdec = now;
113
114 /* Reuse "now" */
115 now = total_count;
116 do_div(now, div_timer);
117 timestamp = now;
118
119 return timestamp;
120 }
121
get_timer(ulong base_ticks)122 ulong get_timer (ulong base_ticks)
123 {
124 return get_timer_masked () - base_ticks;
125 }
126
127 /* delay usec useconds */
__udelay(unsigned long usec)128 void __udelay(unsigned long usec)
129 {
130 ulong tmo, tmp;
131
132 /* Convert to U-Boot ticks */
133 tmo = usec * CONFIG_SYS_HZ;
134 tmo /= (1000000L);
135
136 tmp = get_timer_masked(); /* get current timestamp */
137 tmo += tmp; /* form target timestamp */
138
139 while (get_timer_masked () < tmo) {/* loop till event */
140 /*NOP*/;
141 }
142 }
143
144 /*
145 * This function is derived from PowerPC code (read timebase as long long).
146 * On ARM it just returns the timer value.
147 */
get_ticks(void)148 unsigned long long get_ticks(void)
149 {
150 return get_timer(0);
151 }
152
153 /*
154 * Return the timebase clock frequency
155 * i.e. how often the timer decrements
156 */
get_tbclk(void)157 ulong get_tbclk(void)
158 {
159 unsigned long long tmp = CONFIG_SYS_HZ_CLOCK;
160
161 do_div(tmp, div_clock);
162
163 return tmp;
164 }
165