2 * arch/sh/kernel/time_64.c
4 * Copyright (C) 2000, 2001 Paolo Alberelli
5 * Copyright (C) 2003 - 2007 Paul Mundt
6 * Copyright (C) 2003 Richard Curnow
8 * Original TMU/RTC code taken from sh version.
9 * Copyright (C) 1999 Tetsuya Okada & Niibe Yutaka
10 * Some code taken from i386 version.
11 * Copyright (C) 1991, 1992, 1995 Linus Torvalds
13 * This file is subject to the terms and conditions of the GNU General Public
14 * License. See the file "COPYING" in the main directory of this archive
17 #include <linux/errno.h>
18 #include <linux/rwsem.h>
19 #include <linux/sched.h>
20 #include <linux/kernel.h>
21 #include <linux/param.h>
22 #include <linux/string.h>
24 #include <linux/interrupt.h>
25 #include <linux/time.h>
26 #include <linux/delay.h>
27 #include <linux/init.h>
28 #include <linux/profile.h>
29 #include <linux/smp.h>
30 #include <linux/module.h>
31 #include <linux/bcd.h>
32 #include <linux/timex.h>
33 #include <linux/irq.h>
35 #include <linux/platform_device.h>
36 #include <cpu/registers.h> /* required by inline __asm__ stmt. */
38 #include <asm/addrspace.h>
39 #include <asm/processor.h>
40 #include <asm/uaccess.h>
41 #include <asm/delay.h>
42 #include <asm/clock.h>
44 #define TMU_TOCR_INIT 0x00
45 #define TMU0_TCR_INIT 0x0020
46 #define TMU_TSTR_INIT 1
47 #define TMU_TSTR_OFF 0
50 #define RTC_BLOCK_OFF 0x01040000
51 #define RTC_BASE PHYS_PERIPHERAL_BLOCK + RTC_BLOCK_OFF
52 #define RTC_RCR1_CIE 0x10 /* Carry Interrupt Enable */
53 #define RTC_RCR1 (rtc_base + 0x38)
55 /* Time Management Unit */
56 #define TMU_BLOCK_OFF 0x01020000
57 #define TMU_BASE PHYS_PERIPHERAL_BLOCK + TMU_BLOCK_OFF
58 #define TMU0_BASE tmu_base + 0x8 + (0xc * 0x0)
59 #define TMU1_BASE tmu_base + 0x8 + (0xc * 0x1)
60 #define TMU2_BASE tmu_base + 0x8 + (0xc * 0x2)
62 #define TMU_TOCR tmu_base+0x0 /* Byte access */
63 #define TMU_TSTR tmu_base+0x4 /* Byte access */
65 #define TMU0_TCOR TMU0_BASE+0x0 /* Long access */
66 #define TMU0_TCNT TMU0_BASE+0x4 /* Long access */
67 #define TMU0_TCR TMU0_BASE+0x8 /* Word access */
69 #define TICK_SIZE (tick_nsec / 1000)
71 static unsigned long tmu_base, rtc_base;
72 unsigned long cprc_base;
74 /* Variables to allow interpolation of time of day to resolution better than a
77 /* This is effectively protected by xtime_lock */
78 static unsigned long ctc_last_interrupt;
79 static unsigned long long usecs_per_jiffy = 1000000/HZ; /* Approximation */
81 #define CTC_JIFFY_SCALE_SHIFT 40
83 /* 2**CTC_JIFFY_SCALE_SHIFT / ctc_ticks_per_jiffy */
84 static unsigned long long scaled_recip_ctc_ticks_per_jiffy;
86 /* Estimate number of microseconds that have elapsed since the last timer tick,
87 by scaling the delta that has occurred in the CTC register.
89 WARNING WARNING WARNING : This algorithm relies on the CTC decrementing at
90 the CPU clock rate. If the CPU sleeps, the CTC stops counting. Bear this
91 in mind if enabling SLEEP_WORKS in process.c. In that case, this algorithm
92 probably needs to use TMU.TCNT0 instead. This will work even if the CPU is
93 sleeping, though will be coarser.
95 FIXME : What if usecs_per_tick is moving around too much, e.g. if an adjtime
96 is running or if the freq or tick arguments of adjtimex are modified after
97 we have calibrated the scaling factor? This will result in either a jump at
98 the end of a tick period, or a wrap backwards at the start of the next one,
99 if the application is reading the time of day often enough. I think we
100 ought to do better than this. For this reason, usecs_per_jiffy is left
101 separated out in the calculation below. This allows some future hook into
102 the adjtime-related stuff in kernel/timer.c to remove this hazard.
106 static unsigned long usecs_since_tick(void)
108 unsigned long long current_ctc;
109 long ctc_ticks_since_interrupt;
110 unsigned long long ull_ctc_ticks_since_interrupt;
111 unsigned long result;
113 unsigned long long mul1_out;
114 unsigned long long mul1_out_high;
115 unsigned long long mul2_out_low, mul2_out_high;
117 /* Read CTC register */
118 asm ("getcon cr62, %0" : "=r" (current_ctc));
119 /* Note, the CTC counts down on each CPU clock, not up.
120 Note(2), use long type to get correct wraparound arithmetic when
121 the counter crosses zero. */
122 ctc_ticks_since_interrupt = (long) ctc_last_interrupt - (long) current_ctc;
123 ull_ctc_ticks_since_interrupt = (unsigned long long) ctc_ticks_since_interrupt;
125 /* Inline assembly to do 32x32x32->64 multiplier */
126 asm volatile ("mulu.l %1, %2, %0" :
128 "r" (ull_ctc_ticks_since_interrupt), "r" (usecs_per_jiffy));
130 mul1_out_high = mul1_out >> 32;
132 asm volatile ("mulu.l %1, %2, %0" :
133 "=r" (mul2_out_low) :
134 "r" (mul1_out), "r" (scaled_recip_ctc_ticks_per_jiffy));
137 asm volatile ("mulu.l %1, %2, %0" :
138 "=r" (mul2_out_high) :
139 "r" (mul1_out_high), "r" (scaled_recip_ctc_ticks_per_jiffy));
142 result = (unsigned long) (((mul2_out_high << 32) + mul2_out_low) >> CTC_JIFFY_SCALE_SHIFT);
147 u32 arch_gettimeoffset(void)
149 return usecs_since_tick() * 1000;
153 static void null_rtc_get_time(struct timespec *tv)
155 tv->tv_sec = mktime(2000, 1, 1, 0, 0, 0);
159 static int null_rtc_set_time(const time_t secs)
164 void (*rtc_sh_get_time)(struct timespec *) = null_rtc_get_time;
165 int (*rtc_sh_set_time)(const time_t) = null_rtc_set_time;
167 /* last time the RTC clock got updated */
168 static long last_rtc_update;
171 * timer_interrupt() needs to keep up the real-time clock,
172 * as well as call the "do_timer()" routine every clocktick
174 static inline void do_timer_interrupt(void)
176 unsigned long long current_ctc;
179 profile_tick(CPU_PROFILING);
182 * Here we are in the timer irq handler. We just have irqs locally
183 * disabled but we don't know if the timer_bh is running on the other
184 * CPU. We need to avoid to SMP race with it. NOTE: we don' t need
185 * the irq version of write_lock because as just said we have irq
186 * locally disabled. -arca
188 write_seqlock(&xtime_lock);
189 asm ("getcon cr62, %0" : "=r" (current_ctc));
190 ctc_last_interrupt = (unsigned long) current_ctc;
195 * If we have an externally synchronized Linux clock, then update
196 * RTC clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
197 * called as close as possible to 500 ms before the new second starts.
200 xtime.tv_sec > last_rtc_update + 660 &&
201 (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
202 (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) {
203 if (rtc_sh_set_time(xtime.tv_sec) == 0)
204 last_rtc_update = xtime.tv_sec;
206 /* do it again in 60 s */
207 last_rtc_update = xtime.tv_sec - 600;
209 write_sequnlock(&xtime_lock);
212 update_process_times(user_mode(get_irq_regs()));
217 * This is the same as the above, except we _also_ save the current
218 * Time Stamp Counter value at the time of the timer interrupt, so that
219 * we later on can estimate the time of day more exactly.
221 static irqreturn_t timer_interrupt(int irq, void *dev_id)
223 unsigned long timer_status;
226 timer_status = ctrl_inw(TMU0_TCR);
227 timer_status &= ~0x100;
228 ctrl_outw(timer_status, TMU0_TCR);
230 do_timer_interrupt();
235 static struct irqaction irq0 = {
236 .handler = timer_interrupt,
237 .flags = IRQF_DISABLED,
241 void __init time_init(void)
243 unsigned long interval;
246 tmu_base = (unsigned long)ioremap_nocache(TMU_BASE, 1024);
248 panic("Unable to remap TMU\n");
251 rtc_base = (unsigned long)ioremap_nocache(RTC_BASE, 1024);
253 panic("Unable to remap RTC\n");
256 clk = clk_get(NULL, "cpu_clk");
257 scaled_recip_ctc_ticks_per_jiffy = ((1ULL << CTC_JIFFY_SCALE_SHIFT) /
258 (unsigned long long)(clk_get_rate(clk) / HZ));
260 rtc_sh_get_time(&xtime);
262 setup_irq(TIMER_IRQ, &irq0);
264 clk = clk_get(NULL, "module_clk");
265 interval = (clk_get_rate(clk)/(HZ*4));
267 printk("Interval = %ld\n", interval);
270 ctrl_outb(TMU_TSTR_OFF, TMU_TSTR);
271 ctrl_outb(TMU_TOCR_INIT, TMU_TOCR);
272 ctrl_outw(TMU0_TCR_INIT, TMU0_TCR);
273 ctrl_outl(interval, TMU0_TCOR);
274 ctrl_outl(interval, TMU0_TCNT);
275 ctrl_outb(TMU_TSTR_INIT, TMU_TSTR);
278 static struct resource rtc_resources[] = {
280 /* RTC base, filled in by rtc_init */
281 .flags = IORESOURCE_IO,
286 .flags = IORESOURCE_IRQ,
291 .flags = IORESOURCE_IRQ,
296 .flags = IORESOURCE_IRQ,
300 static struct platform_device rtc_device = {
303 .num_resources = ARRAY_SIZE(rtc_resources),
304 .resource = rtc_resources,
307 static int __init rtc_init(void)
309 rtc_resources[0].start = rtc_base;
310 rtc_resources[0].end = rtc_resources[0].start + 0x58 - 1;
312 return platform_device_register(&rtc_device);
314 device_initcall(rtc_init);