PCI: i386: traps, change VENDOR to DEVICE
[wrt350n-kernel.git] / arch / arm / mach-sa1100 / time.c
blob29cb0c1604ab896c719c86be3b147cbf1b1a737d
1 /*
2 * linux/arch/arm/mach-sa1100/time.c
4 * Copyright (C) 1998 Deborah Wallach.
5 * Twiddles (C) 1999 Hugo Fiennes <hugo@empeg.com>
6 *
7 * 2000/03/29 (C) Nicolas Pitre <nico@cam.org>
8 * Rewritten: big cleanup, much simpler, better HZ accuracy.
11 #include <linux/init.h>
12 #include <linux/errno.h>
13 #include <linux/interrupt.h>
14 #include <linux/irq.h>
15 #include <linux/timex.h>
16 #include <linux/signal.h>
18 #include <asm/mach/time.h>
19 #include <asm/hardware.h>
21 #define RTC_DEF_DIVIDER (32768 - 1)
22 #define RTC_DEF_TRIM 0
24 static unsigned long __init sa1100_get_rtc_time(void)
27 * According to the manual we should be able to let RTTR be zero
28 * and then a default divisor for a 32.768KHz clock is used.
29 * Apparently this doesn't work, at least for my SA1110 rev 5.
30 * If the clock divider is uninitialized then reset it to the
31 * default value to get the 1Hz clock.
33 if (RTTR == 0) {
34 RTTR = RTC_DEF_DIVIDER + (RTC_DEF_TRIM << 16);
35 printk(KERN_WARNING "Warning: uninitialized Real Time Clock\n");
36 /* The current RTC value probably doesn't make sense either */
37 RCNR = 0;
38 return 0;
40 return RCNR;
43 static int sa1100_set_rtc(void)
45 unsigned long current_time = xtime.tv_sec;
47 if (RTSR & RTSR_ALE) {
48 /* make sure not to forward the clock over an alarm */
49 unsigned long alarm = RTAR;
50 if (current_time >= alarm && alarm >= RCNR)
51 return -ERESTARTSYS;
53 RCNR = current_time;
54 return 0;
57 /* IRQs are disabled before entering here from do_gettimeofday() */
58 static unsigned long sa1100_gettimeoffset (void)
60 unsigned long ticks_to_match, elapsed, usec;
62 /* Get ticks before next timer match */
63 ticks_to_match = OSMR0 - OSCR;
65 /* We need elapsed ticks since last match */
66 elapsed = LATCH - ticks_to_match;
68 /* Now convert them to usec */
69 usec = (unsigned long)(elapsed * (tick_nsec / 1000))/LATCH;
71 return usec;
74 #ifdef CONFIG_NO_IDLE_HZ
75 static unsigned long initial_match;
76 static int match_posponed;
77 #endif
79 static irqreturn_t
80 sa1100_timer_interrupt(int irq, void *dev_id)
82 unsigned int next_match;
84 write_seqlock(&xtime_lock);
86 #ifdef CONFIG_NO_IDLE_HZ
87 if (match_posponed) {
88 match_posponed = 0;
89 OSMR0 = initial_match;
91 #endif
94 * Loop until we get ahead of the free running timer.
95 * This ensures an exact clock tick count and time accuracy.
96 * Since IRQs are disabled at this point, coherence between
97 * lost_ticks(updated in do_timer()) and the match reg value is
98 * ensured, hence we can use do_gettimeofday() from interrupt
99 * handlers.
101 do {
102 timer_tick();
103 OSSR = OSSR_M0; /* Clear match on timer 0 */
104 next_match = (OSMR0 += LATCH);
105 } while ((signed long)(next_match - OSCR) <= 0);
107 write_sequnlock(&xtime_lock);
109 return IRQ_HANDLED;
112 static struct irqaction sa1100_timer_irq = {
113 .name = "SA11xx Timer Tick",
114 .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
115 .handler = sa1100_timer_interrupt,
118 static void __init sa1100_timer_init(void)
120 struct timespec tv;
121 unsigned long flags;
123 set_rtc = sa1100_set_rtc;
125 tv.tv_nsec = 0;
126 tv.tv_sec = sa1100_get_rtc_time();
127 do_settimeofday(&tv);
129 OIER = 0; /* disable any timer interrupts */
130 OSSR = 0xf; /* clear status on all timers */
131 setup_irq(IRQ_OST0, &sa1100_timer_irq);
132 local_irq_save(flags);
133 OIER = OIER_E0; /* enable match on timer 0 to cause interrupts */
134 OSMR0 = OSCR + LATCH; /* set initial match */
135 local_irq_restore(flags);
138 #ifdef CONFIG_NO_IDLE_HZ
139 static int sa1100_dyn_tick_enable_disable(void)
141 /* nothing to do */
142 return 0;
145 static void sa1100_dyn_tick_reprogram(unsigned long ticks)
147 if (ticks > 1) {
148 initial_match = OSMR0;
149 OSMR0 = initial_match + ticks * LATCH;
150 match_posponed = 1;
154 static irqreturn_t
155 sa1100_dyn_tick_handler(int irq, void *dev_id)
157 if (match_posponed) {
158 match_posponed = 0;
159 OSMR0 = initial_match;
160 if ((signed long)(initial_match - OSCR) <= 0)
161 return sa1100_timer_interrupt(irq, dev_id);
163 return IRQ_NONE;
166 static struct dyn_tick_timer sa1100_dyn_tick = {
167 .enable = sa1100_dyn_tick_enable_disable,
168 .disable = sa1100_dyn_tick_enable_disable,
169 .reprogram = sa1100_dyn_tick_reprogram,
170 .handler = sa1100_dyn_tick_handler,
172 #endif
174 #ifdef CONFIG_PM
175 unsigned long osmr[4], oier;
177 static void sa1100_timer_suspend(void)
179 osmr[0] = OSMR0;
180 osmr[1] = OSMR1;
181 osmr[2] = OSMR2;
182 osmr[3] = OSMR3;
183 oier = OIER;
186 static void sa1100_timer_resume(void)
188 OSSR = 0x0f;
189 OSMR0 = osmr[0];
190 OSMR1 = osmr[1];
191 OSMR2 = osmr[2];
192 OSMR3 = osmr[3];
193 OIER = oier;
196 * OSMR0 is the system timer: make sure OSCR is sufficiently behind
198 OSCR = OSMR0 - LATCH;
200 #else
201 #define sa1100_timer_suspend NULL
202 #define sa1100_timer_resume NULL
203 #endif
205 struct sys_timer sa1100_timer = {
206 .init = sa1100_timer_init,
207 .suspend = sa1100_timer_suspend,
208 .resume = sa1100_timer_resume,
209 .offset = sa1100_gettimeoffset,
210 #ifdef CONFIG_NO_IDLE_HZ
211 .dyn_tick = &sa1100_dyn_tick,
212 #endif