diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/arm/mach-sa1100/time.c |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'arch/arm/mach-sa1100/time.c')
-rw-r--r-- | arch/arm/mach-sa1100/time.c | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/arch/arm/mach-sa1100/time.c b/arch/arm/mach-sa1100/time.c new file mode 100644 index 000000000000..19b0c0fd6377 --- /dev/null +++ b/arch/arm/mach-sa1100/time.c | |||
@@ -0,0 +1,159 @@ | |||
1 | /* | ||
2 | * linux/arch/arm/mach-sa1100/time.c | ||
3 | * | ||
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. | ||
9 | * | ||
10 | */ | ||
11 | #include <linux/init.h> | ||
12 | #include <linux/errno.h> | ||
13 | #include <linux/interrupt.h> | ||
14 | #include <linux/timex.h> | ||
15 | #include <linux/signal.h> | ||
16 | |||
17 | #include <asm/mach/time.h> | ||
18 | #include <asm/hardware.h> | ||
19 | |||
20 | #define RTC_DEF_DIVIDER (32768 - 1) | ||
21 | #define RTC_DEF_TRIM 0 | ||
22 | |||
23 | static unsigned long __init sa1100_get_rtc_time(void) | ||
24 | { | ||
25 | /* | ||
26 | * According to the manual we should be able to let RTTR be zero | ||
27 | * and then a default diviser for a 32.768KHz clock is used. | ||
28 | * Apparently this doesn't work, at least for my SA1110 rev 5. | ||
29 | * If the clock divider is uninitialized then reset it to the | ||
30 | * default value to get the 1Hz clock. | ||
31 | */ | ||
32 | if (RTTR == 0) { | ||
33 | RTTR = RTC_DEF_DIVIDER + (RTC_DEF_TRIM << 16); | ||
34 | printk(KERN_WARNING "Warning: uninitialized Real Time Clock\n"); | ||
35 | /* The current RTC value probably doesn't make sense either */ | ||
36 | RCNR = 0; | ||
37 | return 0; | ||
38 | } | ||
39 | return RCNR; | ||
40 | } | ||
41 | |||
42 | static int sa1100_set_rtc(void) | ||
43 | { | ||
44 | unsigned long current_time = xtime.tv_sec; | ||
45 | |||
46 | if (RTSR & RTSR_ALE) { | ||
47 | /* make sure not to forward the clock over an alarm */ | ||
48 | unsigned long alarm = RTAR; | ||
49 | if (current_time >= alarm && alarm >= RCNR) | ||
50 | return -ERESTARTSYS; | ||
51 | } | ||
52 | RCNR = current_time; | ||
53 | return 0; | ||
54 | } | ||
55 | |||
56 | /* IRQs are disabled before entering here from do_gettimeofday() */ | ||
57 | static unsigned long sa1100_gettimeoffset (void) | ||
58 | { | ||
59 | unsigned long ticks_to_match, elapsed, usec; | ||
60 | |||
61 | /* Get ticks before next timer match */ | ||
62 | ticks_to_match = OSMR0 - OSCR; | ||
63 | |||
64 | /* We need elapsed ticks since last match */ | ||
65 | elapsed = LATCH - ticks_to_match; | ||
66 | |||
67 | /* Now convert them to usec */ | ||
68 | usec = (unsigned long)(elapsed * (tick_nsec / 1000))/LATCH; | ||
69 | |||
70 | return usec; | ||
71 | } | ||
72 | |||
73 | /* | ||
74 | * We will be entered with IRQs enabled. | ||
75 | * | ||
76 | * Loop until we get ahead of the free running timer. | ||
77 | * This ensures an exact clock tick count and time accuracy. | ||
78 | * IRQs are disabled inside the loop to ensure coherence between | ||
79 | * lost_ticks (updated in do_timer()) and the match reg value, so we | ||
80 | * can use do_gettimeofday() from interrupt handlers. | ||
81 | */ | ||
82 | static irqreturn_t | ||
83 | sa1100_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs) | ||
84 | { | ||
85 | unsigned int next_match; | ||
86 | |||
87 | write_seqlock(&xtime_lock); | ||
88 | |||
89 | do { | ||
90 | timer_tick(regs); | ||
91 | OSSR = OSSR_M0; /* Clear match on timer 0 */ | ||
92 | next_match = (OSMR0 += LATCH); | ||
93 | } while ((signed long)(next_match - OSCR) <= 0); | ||
94 | |||
95 | write_sequnlock(&xtime_lock); | ||
96 | |||
97 | return IRQ_HANDLED; | ||
98 | } | ||
99 | |||
100 | static struct irqaction sa1100_timer_irq = { | ||
101 | .name = "SA11xx Timer Tick", | ||
102 | .flags = SA_INTERRUPT, | ||
103 | .handler = sa1100_timer_interrupt | ||
104 | }; | ||
105 | |||
106 | static void __init sa1100_timer_init(void) | ||
107 | { | ||
108 | struct timespec tv; | ||
109 | |||
110 | set_rtc = sa1100_set_rtc; | ||
111 | |||
112 | tv.tv_nsec = 0; | ||
113 | tv.tv_sec = sa1100_get_rtc_time(); | ||
114 | do_settimeofday(&tv); | ||
115 | |||
116 | OSMR0 = 0; /* set initial match at 0 */ | ||
117 | OSSR = 0xf; /* clear status on all timers */ | ||
118 | setup_irq(IRQ_OST0, &sa1100_timer_irq); | ||
119 | OIER |= OIER_E0; /* enable match on timer 0 to cause interrupts */ | ||
120 | OSCR = 0; /* initialize free-running timer, force first match */ | ||
121 | } | ||
122 | |||
123 | #ifdef CONFIG_PM | ||
124 | unsigned long osmr[4], oier; | ||
125 | |||
126 | static void sa1100_timer_suspend(void) | ||
127 | { | ||
128 | osmr[0] = OSMR0; | ||
129 | osmr[1] = OSMR1; | ||
130 | osmr[2] = OSMR2; | ||
131 | osmr[3] = OSMR3; | ||
132 | oier = OIER; | ||
133 | } | ||
134 | |||
135 | static void sa1100_timer_resume(void) | ||
136 | { | ||
137 | OSSR = 0x0f; | ||
138 | OSMR0 = osmr[0]; | ||
139 | OSMR1 = osmr[1]; | ||
140 | OSMR2 = osmr[2]; | ||
141 | OSMR3 = osmr[3]; | ||
142 | OIER = oier; | ||
143 | |||
144 | /* | ||
145 | * OSMR0 is the system timer: make sure OSCR is sufficiently behind | ||
146 | */ | ||
147 | OSCR = OSMR0 - LATCH; | ||
148 | } | ||
149 | #else | ||
150 | #define sa1100_timer_suspend NULL | ||
151 | #define sa1100_timer_resume NULL | ||
152 | #endif | ||
153 | |||
154 | struct sys_timer sa1100_timer = { | ||
155 | .init = sa1100_timer_init, | ||
156 | .suspend = sa1100_timer_suspend, | ||
157 | .resume = sa1100_timer_resume, | ||
158 | .offset = sa1100_gettimeoffset, | ||
159 | }; | ||