1 /*
2 * linux/arch/unicore32/kernel/time.c
3 *
4 * Code specific to PKUnity SoC and UniCore ISA
5 *
6 * Maintained by GUAN Xue-tao <gxt@mprc.pku.edu.cn>
7 * Copyright (C) 2001-2010 Guan Xuetao
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
12 */
13 #include <linux/init.h>
14 #include <linux/errno.h>
15 #include <linux/interrupt.h>
16 #include <linux/irq.h>
17 #include <linux/timex.h>
18 #include <linux/clockchips.h>
19
20 #include <mach/hardware.h>
21
22 #define MIN_OSCR_DELTA 2
23
24 static irqreturn_t puv3_ost0_interrupt(int irq, void *dev_id)
25 {
26 struct clock_event_device *c = dev_id;
27
28 /* Disarm the compare/match, signal the event. */
29 writel(readl(OST_OIER) & ~OST_OIER_E0, OST_OIER);
30 writel(readl(OST_OSSR) & ~OST_OSSR_M0, OST_OSSR);
31 c->event_handler(c);
32
33 return IRQ_HANDLED;
34 }
35
36 static int
37 puv3_osmr0_set_next_event(unsigned long delta, struct clock_event_device *c)
38 {
39 unsigned long next, oscr;
40
41 writel(readl(OST_OIER) | OST_OIER_E0, OST_OIER);
42 next = readl(OST_OSCR) + delta;
43 writel(next, OST_OSMR0);
44 oscr = readl(OST_OSCR);
45
46 return (signed)(next - oscr) <= MIN_OSCR_DELTA ? -ETIME : 0;
47 }
48
49 static int puv3_osmr0_shutdown(struct clock_event_device *evt)
50 {
51 writel(readl(OST_OIER) & ~OST_OIER_E0, OST_OIER);
52 writel(readl(OST_OSSR) & ~OST_OSSR_M0, OST_OSSR);
53 return 0;
54 }
55
56 static struct clock_event_device ckevt_puv3_osmr0 = {
57 .name = "osmr0",
58 .features = CLOCK_EVT_FEAT_ONESHOT,
59 .rating = 200,
60 .set_next_event = puv3_osmr0_set_next_event,
61 .set_state_shutdown = puv3_osmr0_shutdown,
62 .set_state_oneshot = puv3_osmr0_shutdown,
63 };
64
65 static u64 puv3_read_oscr(struct clocksource *cs)
66 {
67 return readl(OST_OSCR);
68 }
69
70 static struct clocksource cksrc_puv3_oscr = {
71 .name = "oscr",
72 .rating = 200,
73 .read = puv3_read_oscr,
74 .mask = CLOCKSOURCE_MASK(32),
75 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
76 };
77
78 static struct irqaction puv3_timer_irq = {
79 .name = "ost0",
80 .flags = IRQF_TIMER | IRQF_IRQPOLL,
81 .handler = puv3_ost0_interrupt,
82 .dev_id = &ckevt_puv3_osmr0,
83 };
84
85 void __init time_init(void)
86 {
87 writel(0, OST_OIER); /* disable any timer interrupts */
88 writel(0, OST_OSSR); /* clear status on all timers */
89
90 clockevents_calc_mult_shift(&ckevt_puv3_osmr0, CLOCK_TICK_RATE, 5);
91
92 ckevt_puv3_osmr0.max_delta_ns =
93 clockevent_delta2ns(0x7fffffff, &ckevt_puv3_osmr0);
94 ckevt_puv3_osmr0.max_delta_ticks = 0x7fffffff;
95 ckevt_puv3_osmr0.min_delta_ns =
96 clockevent_delta2ns(MIN_OSCR_DELTA * 2, &ckevt_puv3_osmr0) + 1;
97 ckevt_puv3_osmr0.min_delta_ticks = MIN_OSCR_DELTA * 2;
98 ckevt_puv3_osmr0.cpumask = cpumask_of(0);
99
100 setup_irq(IRQ_TIMER0, &puv3_timer_irq);
101
102 clocksource_register_hz(&cksrc_puv3_oscr, CLOCK_TICK_RATE);
103 clockevents_register_device(&ckevt_puv3_osmr0);
104 }
105
106 #ifdef CONFIG_PM
107 unsigned long osmr[4], oier;
108
109 void puv3_timer_suspend(void)
110 {
111 osmr[0] = readl(OST_OSMR0);
112 osmr[1] = readl(OST_OSMR1);
113 osmr[2] = readl(OST_OSMR2);
114 osmr[3] = readl(OST_OSMR3);
115 oier = readl(OST_OIER);
116 }
117
118 void puv3_timer_resume(void)
119 {
120 writel(0, OST_OSSR);
121 writel(osmr[0], OST_OSMR0);
122 writel(osmr[1], OST_OSMR1);
123 writel(osmr[2], OST_OSMR2);
124 writel(osmr[3], OST_OSMR3);
125 writel(oier, OST_OIER);
126
127 /*
128 * OSMR0 is the system timer: make sure OSCR is sufficiently behind
129 */
130 writel(readl(OST_OSMR0) - LATCH, OST_OSCR);
131 }
132 #else
133 void puv3_timer_suspend(void) { };
134 void puv3_timer_resume(void) { };
135 #endif
136
137
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