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49cbe786 EM |
1 | /* |
2 | * linux/arch/arm/mach-mmp/time.c | |
3 | * | |
4 | * Support for clocksource and clockevents | |
5 | * | |
6 | * Copyright (C) 2008 Marvell International Ltd. | |
7 | * All rights reserved. | |
8 | * | |
9 | * 2008-04-11: Jason Chagas <Jason.chagas@marvell.com> | |
10 | * 2008-10-08: Bin Yang <bin.yang@marvell.com> | |
11 | * | |
12 | * The timers module actually includes three timers, each timer with upto | |
13 | * three match comparators. Timer #0 is used here in free-running mode as | |
14 | * the clock source, and match comparator #1 used as clock event device. | |
15 | * | |
16 | * This program is free software; you can redistribute it and/or modify | |
17 | * it under the terms of the GNU General Public License version 2 as | |
18 | * published by the Free Software Foundation. | |
19 | */ | |
20 | ||
21 | #include <linux/init.h> | |
22 | #include <linux/kernel.h> | |
23 | #include <linux/interrupt.h> | |
24 | #include <linux/clockchips.h> | |
25 | ||
26 | #include <linux/io.h> | |
27 | #include <linux/irq.h> | |
28 | #include <linux/sched.h> | |
29 | #include <linux/cnt32_to_63.h> | |
30 | ||
31 | #include <mach/addr-map.h> | |
32 | #include <mach/regs-timers.h> | |
33 | #include <mach/irqs.h> | |
34 | ||
35 | #include "clock.h" | |
36 | ||
37 | #define TIMERS_VIRT_BASE TIMERS1_VIRT_BASE | |
38 | ||
39 | #define MAX_DELTA (0xfffffffe) | |
40 | #define MIN_DELTA (16) | |
41 | ||
42 | #define TCR2NS_SCALE_FACTOR 10 | |
43 | ||
44 | static unsigned long tcr2ns_scale; | |
45 | ||
46 | static void __init set_tcr2ns_scale(unsigned long tcr_rate) | |
47 | { | |
48 | unsigned long long v = 1000000000ULL << TCR2NS_SCALE_FACTOR; | |
49 | do_div(v, tcr_rate); | |
50 | tcr2ns_scale = v; | |
51 | /* | |
52 | * We want an even value to automatically clear the top bit | |
53 | * returned by cnt32_to_63() without an additional run time | |
54 | * instruction. So if the LSB is 1 then round it up. | |
55 | */ | |
56 | if (tcr2ns_scale & 1) | |
57 | tcr2ns_scale++; | |
58 | } | |
59 | ||
60 | /* | |
61 | * FIXME: the timer needs some delay to stablize the counter capture | |
62 | */ | |
63 | static inline uint32_t timer_read(void) | |
64 | { | |
65 | int delay = 100; | |
66 | ||
67 | __raw_writel(1, TIMERS_VIRT_BASE + TMR_CVWR(0)); | |
68 | ||
69 | while (delay--) | |
70 | cpu_relax(); | |
71 | ||
72 | return __raw_readl(TIMERS_VIRT_BASE + TMR_CVWR(0)); | |
73 | } | |
74 | ||
75 | unsigned long long sched_clock(void) | |
76 | { | |
77 | unsigned long long v = cnt32_to_63(timer_read()); | |
78 | return (v * tcr2ns_scale) >> TCR2NS_SCALE_FACTOR; | |
79 | } | |
80 | ||
81 | static irqreturn_t timer_interrupt(int irq, void *dev_id) | |
82 | { | |
83 | struct clock_event_device *c = dev_id; | |
84 | ||
85 | /* disable and clear pending interrupt status */ | |
86 | __raw_writel(0x0, TIMERS_VIRT_BASE + TMR_IER(0)); | |
87 | __raw_writel(0x1, TIMERS_VIRT_BASE + TMR_ICR(0)); | |
88 | c->event_handler(c); | |
89 | return IRQ_HANDLED; | |
90 | } | |
91 | ||
92 | static int timer_set_next_event(unsigned long delta, | |
93 | struct clock_event_device *dev) | |
94 | { | |
95 | unsigned long flags, next; | |
96 | ||
97 | local_irq_save(flags); | |
98 | ||
99 | /* clear pending interrupt status and enable */ | |
100 | __raw_writel(0x01, TIMERS_VIRT_BASE + TMR_ICR(0)); | |
101 | __raw_writel(0x01, TIMERS_VIRT_BASE + TMR_IER(0)); | |
102 | ||
103 | next = timer_read() + delta; | |
104 | __raw_writel(next, TIMERS_VIRT_BASE + TMR_TN_MM(0, 0)); | |
105 | ||
106 | local_irq_restore(flags); | |
107 | return 0; | |
108 | } | |
109 | ||
110 | static void timer_set_mode(enum clock_event_mode mode, | |
111 | struct clock_event_device *dev) | |
112 | { | |
113 | unsigned long flags; | |
114 | ||
115 | local_irq_save(flags); | |
116 | switch (mode) { | |
117 | case CLOCK_EVT_MODE_ONESHOT: | |
118 | case CLOCK_EVT_MODE_UNUSED: | |
119 | case CLOCK_EVT_MODE_SHUTDOWN: | |
120 | /* disable the matching interrupt */ | |
121 | __raw_writel(0x00, TIMERS_VIRT_BASE + TMR_IER(0)); | |
122 | break; | |
123 | case CLOCK_EVT_MODE_RESUME: | |
124 | case CLOCK_EVT_MODE_PERIODIC: | |
125 | break; | |
126 | } | |
127 | local_irq_restore(flags); | |
128 | } | |
129 | ||
130 | static struct clock_event_device ckevt = { | |
131 | .name = "clockevent", | |
132 | .features = CLOCK_EVT_FEAT_ONESHOT, | |
133 | .shift = 32, | |
134 | .rating = 200, | |
135 | .set_next_event = timer_set_next_event, | |
136 | .set_mode = timer_set_mode, | |
137 | }; | |
138 | ||
f5c81a32 | 139 | static cycle_t clksrc_read(struct clocksource *cs) |
49cbe786 EM |
140 | { |
141 | return timer_read(); | |
142 | } | |
143 | ||
144 | static struct clocksource cksrc = { | |
145 | .name = "clocksource", | |
146 | .shift = 20, | |
147 | .rating = 200, | |
148 | .read = clksrc_read, | |
149 | .mask = CLOCKSOURCE_MASK(32), | |
150 | .flags = CLOCK_SOURCE_IS_CONTINUOUS, | |
151 | }; | |
152 | ||
153 | static void __init timer_config(void) | |
154 | { | |
155 | uint32_t ccr = __raw_readl(TIMERS_VIRT_BASE + TMR_CCR); | |
156 | uint32_t cer = __raw_readl(TIMERS_VIRT_BASE + TMR_CER); | |
157 | uint32_t cmr = __raw_readl(TIMERS_VIRT_BASE + TMR_CMR); | |
158 | ||
159 | __raw_writel(cer & ~0x1, TIMERS_VIRT_BASE + TMR_CER); /* disable */ | |
160 | ||
161 | ccr &= TMR_CCR_CS_0(0x3); | |
162 | __raw_writel(ccr, TIMERS_VIRT_BASE + TMR_CCR); | |
163 | ||
164 | /* free-running mode */ | |
165 | __raw_writel(cmr | 0x01, TIMERS_VIRT_BASE + TMR_CMR); | |
166 | ||
167 | __raw_writel(0x0, TIMERS_VIRT_BASE + TMR_PLCR(0)); /* free-running */ | |
168 | __raw_writel(0x7, TIMERS_VIRT_BASE + TMR_ICR(0)); /* clear status */ | |
169 | __raw_writel(0x0, TIMERS_VIRT_BASE + TMR_IER(0)); | |
170 | ||
171 | /* enable timer counter */ | |
172 | __raw_writel(cer | 0x01, TIMERS_VIRT_BASE + TMR_CER); | |
173 | } | |
174 | ||
175 | static struct irqaction timer_irq = { | |
176 | .name = "timer", | |
177 | .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL, | |
178 | .handler = timer_interrupt, | |
179 | .dev_id = &ckevt, | |
180 | }; | |
181 | ||
182 | void __init timer_init(int irq) | |
183 | { | |
184 | timer_config(); | |
185 | ||
186 | set_tcr2ns_scale(CLOCK_TICK_RATE); | |
187 | ||
188 | ckevt.mult = div_sc(CLOCK_TICK_RATE, NSEC_PER_SEC, ckevt.shift); | |
189 | ckevt.max_delta_ns = clockevent_delta2ns(MAX_DELTA, &ckevt); | |
190 | ckevt.min_delta_ns = clockevent_delta2ns(MIN_DELTA, &ckevt); | |
191 | ckevt.cpumask = cpumask_of(0); | |
192 | ||
193 | cksrc.mult = clocksource_hz2mult(CLOCK_TICK_RATE, cksrc.shift); | |
194 | ||
195 | setup_irq(irq, &timer_irq); | |
196 | ||
197 | clocksource_register(&cksrc); | |
198 | clockevents_register_device(&ckevt); | |
199 | } |