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time.c
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1 /*
2  * linux/arch/m32r/kernel/time.c
3  *
4  * Copyright (c) 2001, 2002 Hiroyuki Kondo, Hirokazu Takata,
5  * Hitoshi Yamamoto
6  * Taken from i386 version.
7  * Copyright (C) 1991, 1992, 1995 Linus Torvalds
8  * Copyright (C) 1996, 1997, 1998 Ralf Baechle
9  *
10  * This file contains the time handling details for PC-style clocks as
11  * found in some MIPS systems.
12  *
13  * Some code taken from sh version.
14  * Copyright (C) 1999 Tetsuya Okada & Niibe Yutaka
15  * Copyright (C) 2000 Philipp Rumpf <[email protected]>
16  */
17 
18 #undef DEBUG_TIMER
19 
20 #include <linux/errno.h>
21 #include <linux/init.h>
22 #include <linux/module.h>
23 #include <linux/sched.h>
24 #include <linux/kernel.h>
25 #include <linux/param.h>
26 #include <linux/string.h>
27 #include <linux/mm.h>
28 #include <linux/interrupt.h>
29 #include <linux/profile.h>
30 
31 #include <asm/io.h>
32 #include <asm/m32r.h>
33 
34 #include <asm/hw_irq.h>
35 
36 #if defined(CONFIG_RTC_DRV_CMOS) || defined(CONFIG_RTC_DRV_CMOS_MODULE)
37 /* this needs a better home */
38 DEFINE_SPINLOCK(rtc_lock);
39 
40 #ifdef CONFIG_RTC_DRV_CMOS_MODULE
41 EXPORT_SYMBOL(rtc_lock);
42 #endif
43 #endif /* pc-style 'CMOS' RTC support */
44 
45 #ifdef CONFIG_SMP
46 extern void smp_local_timer_interrupt(void);
47 #endif
48 
49 #define TICK_SIZE (tick_nsec / 1000)
50 
51 /*
52  * Change this if you have some constant time drift
53  */
54 
55 /* This is for machines which generate the exact clock. */
56 #define USECS_PER_JIFFY (1000000/HZ)
57 
58 static unsigned long latch;
59 
61 {
62  unsigned long elapsed_time = 0; /* [us] */
63 
64 #if defined(CONFIG_CHIP_M32102) || defined(CONFIG_CHIP_XNUX2) \
65  || defined(CONFIG_CHIP_VDEC2) || defined(CONFIG_CHIP_M32700) \
66  || defined(CONFIG_CHIP_OPSP) || defined(CONFIG_CHIP_M32104)
67 #ifndef CONFIG_SMP
68 
69  unsigned long count;
70 
71  /* timer count may underflow right here */
72  count = inl(M32R_MFT2CUT_PORTL);
73 
74  if (inl(M32R_ICU_CR18_PORTL) & 0x00000100) /* underflow check */
75  count = 0;
76 
77  count = (latch - count) * TICK_SIZE;
78  elapsed_time = DIV_ROUND_CLOSEST(count, latch);
79  /* NOTE: LATCH is equal to the "interval" value (= reload count). */
80 
81 #else /* CONFIG_SMP */
82  unsigned long count;
83  static unsigned long p_jiffies = -1;
84  static unsigned long p_count = 0;
85 
86  /* timer count may underflow right here */
87  count = inl(M32R_MFT2CUT_PORTL);
88 
89  if (jiffies == p_jiffies && count > p_count)
90  count = 0;
91 
92  p_jiffies = jiffies;
93  p_count = count;
94 
95  count = (latch - count) * TICK_SIZE;
96  elapsed_time = DIV_ROUND_CLOSEST(count, latch);
97  /* NOTE: LATCH is equal to the "interval" value (= reload count). */
98 #endif /* CONFIG_SMP */
99 #elif defined(CONFIG_CHIP_M32310)
100 #warning do_gettimeoffse not implemented
101 #else
102 #error no chip configuration
103 #endif
104 
105  return elapsed_time * 1000;
106 }
107 
108 /*
109  * timer_interrupt() needs to keep up the real-time clock,
110  * as well as call the "xtime_update()" routine every clocktick
111  */
112 static irqreturn_t timer_interrupt(int irq, void *dev_id)
113 {
114 #ifndef CONFIG_SMP
116 #endif
117  xtime_update(1);
118 
119 #ifndef CONFIG_SMP
121 #endif
122  /* As we return to user mode fire off the other CPU schedulers..
123  this is basically because we don't yet share IRQ's around.
124  This message is rigged to be safe on the 386 - basically it's
125  a hack, so don't look closely for now.. */
126 
127 #ifdef CONFIG_SMP
129  smp_send_timer();
130 #endif
131 
132  return IRQ_HANDLED;
133 }
134 
135 static struct irqaction irq0 = {
136  .handler = timer_interrupt,
137  .flags = IRQF_DISABLED,
138  .name = "MFT2",
139 };
140 
142 {
143  unsigned int epoch, year, mon, day, hour, min, sec;
144 
145  sec = min = hour = day = mon = year = 0;
146  epoch = 0;
147 
148  year = 23;
149  mon = 4;
150  day = 17;
151 
152  /* Attempt to guess the epoch. This is the same heuristic as in rtc.c
153  so no stupid things will happen to timekeeping. Who knows, maybe
154  Ultrix also uses 1952 as epoch ... */
155  if (year > 10 && year < 44)
156  epoch = 1980;
157  else if (year < 96)
158  epoch = 1952;
159  year += epoch;
160 
161  ts->tv_sec = mktime(year, mon, day, hour, min, sec);
162  ts->tv_nsec = (INITIAL_JIFFIES % HZ) * (NSEC_PER_SEC / HZ);
163 }
164 
165 
166 void __init time_init(void)
167 {
168 #if defined(CONFIG_CHIP_M32102) || defined(CONFIG_CHIP_XNUX2) \
169  || defined(CONFIG_CHIP_VDEC2) || defined(CONFIG_CHIP_M32700) \
170  || defined(CONFIG_CHIP_OPSP) || defined(CONFIG_CHIP_M32104)
171 
172  /* M32102 MFT setup */
173  setup_irq(M32R_IRQ_MFT2, &irq0);
174  {
175  unsigned long bus_clock;
176  unsigned short divide;
177 
178  bus_clock = boot_cpu_data.bus_clock;
179  divide = boot_cpu_data.timer_divide;
180  latch = DIV_ROUND_CLOSEST(bus_clock/divide, HZ);
181 
182  printk("Timer start : latch = %ld\n", latch);
183 
186  outl(latch, M32R_MFT2RLD_PORTL);
187  outl(latch, M32R_MFT2CUT_PORTL);
190  }
191 
192 #elif defined(CONFIG_CHIP_M32310)
193 #warning time_init not implemented
194 #else
195 #error no chip configuration
196 #endif
197 }