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
puv3_ost0_interrupt(int irq,void * dev_id)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
puv3_osmr0_set_next_event(unsigned long delta,struct clock_event_device * c)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 void
puv3_osmr0_set_mode(enum clock_event_mode mode,struct clock_event_device * c)50 puv3_osmr0_set_mode(enum clock_event_mode mode, struct clock_event_device *c)
51 {
52 switch (mode) {
53 case CLOCK_EVT_MODE_ONESHOT:
54 case CLOCK_EVT_MODE_UNUSED:
55 case CLOCK_EVT_MODE_SHUTDOWN:
56 writel(readl(OST_OIER) & ~OST_OIER_E0, OST_OIER);
57 writel(readl(OST_OSSR) & ~OST_OSSR_M0, OST_OSSR);
58 break;
59
60 case CLOCK_EVT_MODE_RESUME:
61 case CLOCK_EVT_MODE_PERIODIC:
62 break;
63 }
64 }
65
66 static struct clock_event_device ckevt_puv3_osmr0 = {
67 .name = "osmr0",
68 .features = CLOCK_EVT_FEAT_ONESHOT,
69 .rating = 200,
70 .set_next_event = puv3_osmr0_set_next_event,
71 .set_mode = puv3_osmr0_set_mode,
72 };
73
puv3_read_oscr(struct clocksource * cs)74 static cycle_t puv3_read_oscr(struct clocksource *cs)
75 {
76 return readl(OST_OSCR);
77 }
78
79 static struct clocksource cksrc_puv3_oscr = {
80 .name = "oscr",
81 .rating = 200,
82 .read = puv3_read_oscr,
83 .mask = CLOCKSOURCE_MASK(32),
84 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
85 };
86
87 static struct irqaction puv3_timer_irq = {
88 .name = "ost0",
89 .flags = IRQF_TIMER | IRQF_IRQPOLL,
90 .handler = puv3_ost0_interrupt,
91 .dev_id = &ckevt_puv3_osmr0,
92 };
93
time_init(void)94 void __init time_init(void)
95 {
96 writel(0, OST_OIER); /* disable any timer interrupts */
97 writel(0, OST_OSSR); /* clear status on all timers */
98
99 clockevents_calc_mult_shift(&ckevt_puv3_osmr0, CLOCK_TICK_RATE, 5);
100
101 ckevt_puv3_osmr0.max_delta_ns =
102 clockevent_delta2ns(0x7fffffff, &ckevt_puv3_osmr0);
103 ckevt_puv3_osmr0.min_delta_ns =
104 clockevent_delta2ns(MIN_OSCR_DELTA * 2, &ckevt_puv3_osmr0) + 1;
105 ckevt_puv3_osmr0.cpumask = cpumask_of(0);
106
107 setup_irq(IRQ_TIMER0, &puv3_timer_irq);
108
109 clocksource_register_hz(&cksrc_puv3_oscr, CLOCK_TICK_RATE);
110 clockevents_register_device(&ckevt_puv3_osmr0);
111 }
112
113 #ifdef CONFIG_PM
114 unsigned long osmr[4], oier;
115
puv3_timer_suspend(void)116 void puv3_timer_suspend(void)
117 {
118 osmr[0] = readl(OST_OSMR0);
119 osmr[1] = readl(OST_OSMR1);
120 osmr[2] = readl(OST_OSMR2);
121 osmr[3] = readl(OST_OSMR3);
122 oier = readl(OST_OIER);
123 }
124
puv3_timer_resume(void)125 void puv3_timer_resume(void)
126 {
127 writel(0, OST_OSSR);
128 writel(osmr[0], OST_OSMR0);
129 writel(osmr[1], OST_OSMR1);
130 writel(osmr[2], OST_OSMR2);
131 writel(osmr[3], OST_OSMR3);
132 writel(oier, OST_OIER);
133
134 /*
135 * OSMR0 is the system timer: make sure OSCR is sufficiently behind
136 */
137 writel(readl(OST_OSMR0) - LATCH, OST_OSCR);
138 }
139 #else
puv3_timer_suspend(void)140 void puv3_timer_suspend(void) { };
puv3_timer_resume(void)141 void puv3_timer_resume(void) { };
142 #endif
143
144