1 /*
2 * arch/sh/kernel/time_64.c
3 *
4 * Copyright (C) 2000, 2001 Paolo Alberelli
5 * Copyright (C) 2003 - 2007 Paul Mundt
6 * Copyright (C) 2003 Richard Curnow
7 *
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
12 *
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
15 * for more details.
16 */
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>
23 #include <linux/mm.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>
34 #include <linux/io.h>
35 #include <linux/platform_device.h>
36 #include <cpu/registers.h> /* required by inline __asm__ stmt. */
37 #include <cpu/irq.h>
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>
43
44 #define TMU_TOCR_INIT 0x00
45 #define TMU0_TCR_INIT 0x0020
46 #define TMU_TSTR_INIT 1
47 #define TMU_TSTR_OFF 0
48
49 /* Real Time Clock */
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)
54
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)
61
62 #define TMU_TOCR tmu_base+0x0 /* Byte access */
63 #define TMU_TSTR tmu_base+0x4 /* Byte access */
64
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 */
68
69 #define TICK_SIZE (tick_nsec / 1000)
70
71 static unsigned long tmu_base, rtc_base;
72 unsigned long cprc_base;
73
74 /* Variables to allow interpolation of time of day to resolution better than a
75 * jiffy. */
76
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 */
80
81 #define CTC_JIFFY_SCALE_SHIFT 40
82
83 /* 2**CTC_JIFFY_SCALE_SHIFT / ctc_ticks_per_jiffy */
84 static unsigned long long scaled_recip_ctc_ticks_per_jiffy;
85
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.
88
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.
94
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.
103
104 */
105
usecs_since_tick(void)106 static unsigned long usecs_since_tick(void)
107 {
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;
112
113 unsigned long long mul1_out;
114 unsigned long long mul1_out_high;
115 unsigned long long mul2_out_low, mul2_out_high;
116
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;
124
125 /* Inline assembly to do 32x32x32->64 multiplier */
126 asm volatile ("mulu.l %1, %2, %0" :
127 "=r" (mul1_out) :
128 "r" (ull_ctc_ticks_since_interrupt), "r" (usecs_per_jiffy));
129
130 mul1_out_high = mul1_out >> 32;
131
132 asm volatile ("mulu.l %1, %2, %0" :
133 "=r" (mul2_out_low) :
134 "r" (mul1_out), "r" (scaled_recip_ctc_ticks_per_jiffy));
135
136 #if 1
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));
140 #endif
141
142 result = (unsigned long) (((mul2_out_high << 32) + mul2_out_low) >> CTC_JIFFY_SCALE_SHIFT);
143
144 return result;
145 }
146
do_gettimeofday(struct timeval * tv)147 void do_gettimeofday(struct timeval *tv)
148 {
149 unsigned long flags;
150 unsigned long seq;
151 unsigned long usec, sec;
152
153 do {
154 seq = read_seqbegin_irqsave(&xtime_lock, flags);
155 usec = usecs_since_tick();
156 sec = xtime.tv_sec;
157 usec += xtime.tv_nsec / 1000;
158 } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
159
160 while (usec >= 1000000) {
161 usec -= 1000000;
162 sec++;
163 }
164
165 tv->tv_sec = sec;
166 tv->tv_usec = usec;
167 }
168 EXPORT_SYMBOL(do_gettimeofday);
169
do_settimeofday(struct timespec * tv)170 int do_settimeofday(struct timespec *tv)
171 {
172 time_t wtm_sec, sec = tv->tv_sec;
173 long wtm_nsec, nsec = tv->tv_nsec;
174
175 if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
176 return -EINVAL;
177
178 write_seqlock_irq(&xtime_lock);
179 /*
180 * This is revolting. We need to set "xtime" correctly. However, the
181 * value in this location is the value at the most recent update of
182 * wall time. Discover what correction gettimeofday() would have
183 * made, and then undo it!
184 */
185 nsec -= 1000 * usecs_since_tick();
186
187 wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
188 wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
189
190 set_normalized_timespec(&xtime, sec, nsec);
191 set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
192
193 ntp_clear();
194 write_sequnlock_irq(&xtime_lock);
195 clock_was_set();
196
197 return 0;
198 }
199 EXPORT_SYMBOL(do_settimeofday);
200
201 /* Dummy RTC ops */
null_rtc_get_time(struct timespec * tv)202 static void null_rtc_get_time(struct timespec *tv)
203 {
204 tv->tv_sec = mktime(2000, 1, 1, 0, 0, 0);
205 tv->tv_nsec = 0;
206 }
207
null_rtc_set_time(const time_t secs)208 static int null_rtc_set_time(const time_t secs)
209 {
210 return 0;
211 }
212
213 void (*rtc_sh_get_time)(struct timespec *) = null_rtc_get_time;
214 int (*rtc_sh_set_time)(const time_t) = null_rtc_set_time;
215
216 /* last time the RTC clock got updated */
217 static long last_rtc_update;
218
219 /*
220 * timer_interrupt() needs to keep up the real-time clock,
221 * as well as call the "do_timer()" routine every clocktick
222 */
do_timer_interrupt(void)223 static inline void do_timer_interrupt(void)
224 {
225 unsigned long long current_ctc;
226
227 if (current->pid)
228 profile_tick(CPU_PROFILING);
229
230 /*
231 * Here we are in the timer irq handler. We just have irqs locally
232 * disabled but we don't know if the timer_bh is running on the other
233 * CPU. We need to avoid to SMP race with it. NOTE: we don' t need
234 * the irq version of write_lock because as just said we have irq
235 * locally disabled. -arca
236 */
237 write_seqlock(&xtime_lock);
238 asm ("getcon cr62, %0" : "=r" (current_ctc));
239 ctc_last_interrupt = (unsigned long) current_ctc;
240
241 do_timer(1);
242
243 /*
244 * If we have an externally synchronized Linux clock, then update
245 * RTC clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
246 * called as close as possible to 500 ms before the new second starts.
247 */
248 if (ntp_synced() &&
249 xtime.tv_sec > last_rtc_update + 660 &&
250 (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
251 (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) {
252 if (rtc_sh_set_time(xtime.tv_sec) == 0)
253 last_rtc_update = xtime.tv_sec;
254 else
255 /* do it again in 60 s */
256 last_rtc_update = xtime.tv_sec - 600;
257 }
258 write_sequnlock(&xtime_lock);
259
260 #ifndef CONFIG_SMP
261 update_process_times(user_mode(get_irq_regs()));
262 #endif
263 }
264
265 /*
266 * This is the same as the above, except we _also_ save the current
267 * Time Stamp Counter value at the time of the timer interrupt, so that
268 * we later on can estimate the time of day more exactly.
269 */
timer_interrupt(int irq,void * dev_id)270 static irqreturn_t timer_interrupt(int irq, void *dev_id)
271 {
272 unsigned long timer_status;
273
274 /* Clear UNF bit */
275 timer_status = ctrl_inw(TMU0_TCR);
276 timer_status &= ~0x100;
277 ctrl_outw(timer_status, TMU0_TCR);
278
279 do_timer_interrupt();
280
281 return IRQ_HANDLED;
282 }
283
284 static struct irqaction irq0 = {
285 .handler = timer_interrupt,
286 .flags = IRQF_DISABLED,
287 .mask = CPU_MASK_NONE,
288 .name = "timer",
289 };
290
time_init(void)291 void __init time_init(void)
292 {
293 unsigned long interval;
294 struct clk *clk;
295
296 tmu_base = onchip_remap(TMU_BASE, 1024, "TMU");
297 if (!tmu_base) {
298 panic("Unable to remap TMU\n");
299 }
300
301 rtc_base = onchip_remap(RTC_BASE, 1024, "RTC");
302 if (!rtc_base) {
303 panic("Unable to remap RTC\n");
304 }
305
306 clk = clk_get(NULL, "cpu_clk");
307 scaled_recip_ctc_ticks_per_jiffy = ((1ULL << CTC_JIFFY_SCALE_SHIFT) /
308 (unsigned long long)(clk_get_rate(clk) / HZ));
309
310 rtc_sh_get_time(&xtime);
311
312 setup_irq(TIMER_IRQ, &irq0);
313
314 clk = clk_get(NULL, "module_clk");
315 interval = (clk_get_rate(clk)/(HZ*4));
316
317 printk("Interval = %ld\n", interval);
318
319 /* Start TMU0 */
320 ctrl_outb(TMU_TSTR_OFF, TMU_TSTR);
321 ctrl_outb(TMU_TOCR_INIT, TMU_TOCR);
322 ctrl_outw(TMU0_TCR_INIT, TMU0_TCR);
323 ctrl_outl(interval, TMU0_TCOR);
324 ctrl_outl(interval, TMU0_TCNT);
325 ctrl_outb(TMU_TSTR_INIT, TMU_TSTR);
326 }
327
328 static struct resource rtc_resources[] = {
329 [0] = {
330 /* RTC base, filled in by rtc_init */
331 .flags = IORESOURCE_IO,
332 },
333 [1] = {
334 /* Period IRQ */
335 .start = IRQ_PRI,
336 .flags = IORESOURCE_IRQ,
337 },
338 [2] = {
339 /* Carry IRQ */
340 .start = IRQ_CUI,
341 .flags = IORESOURCE_IRQ,
342 },
343 [3] = {
344 /* Alarm IRQ */
345 .start = IRQ_ATI,
346 .flags = IORESOURCE_IRQ,
347 },
348 };
349
350 static struct platform_device rtc_device = {
351 .name = "sh-rtc",
352 .id = -1,
353 .num_resources = ARRAY_SIZE(rtc_resources),
354 .resource = rtc_resources,
355 };
356
rtc_init(void)357 static int __init rtc_init(void)
358 {
359 rtc_resources[0].start = rtc_base;
360 rtc_resources[0].end = rtc_resources[0].start + 0x58 - 1;
361
362 return platform_device_register(&rtc_device);
363 }
364 device_initcall(rtc_init);
365