2 * Based on arm clockevents implementation and old bfin time tick.
4 * Copyright 2008-2009 Analog Devics Inc.
8 * Licensed under the GPL-2
11 #include <linux/module.h>
12 #include <linux/profile.h>
13 #include <linux/interrupt.h>
14 #include <linux/time.h>
15 #include <linux/timex.h>
16 #include <linux/irq.h>
17 #include <linux/clocksource.h>
18 #include <linux/clockchips.h>
19 #include <linux/cpufreq.h>
21 #include <asm/blackfin.h>
23 #include <asm/gptimers.h>
25 /* Accelerators for sched_clock()
26 * convert from cycles(64bits) => nanoseconds (64bits)
28 * ns = cycles / (freq / ns_per_sec)
29 * ns = cycles * (ns_per_sec / freq)
30 * ns = cycles * (10^9 / (cpu_khz * 10^3))
31 * ns = cycles * (10^6 / cpu_khz)
33 * Then we use scaling math (suggested by george@mvista.com) to get:
34 * ns = cycles * (10^6 * SC / cpu_khz) / SC
35 * ns = cycles * cyc2ns_scale / SC
37 * And since SC is a constant power of two, we can convert the div
40 * We can use khz divisor instead of mhz to keep a better precision, since
41 * cyc2ns_scale is limited to 10^6 * 2^10, which fits in 32 bits.
42 * (mathieu.desnoyers@polymtl.ca)
44 * -johnstul@us.ibm.com "math is hard, lets go shopping!"
47 #define CYC2NS_SCALE_FACTOR 10 /* 2^10, carefully chosen */
49 static inline unsigned long cyc2ns_scale(unsigned long cpu_khz
)
51 return (1000000 << CYC2NS_SCALE_FACTOR
) / cpu_khz
;
54 static inline unsigned long long cycles_2_ns(cycle_t cyc
, unsigned long cyc2ns_scale
)
56 return (cyc
* cyc2ns_scale
) >> CYC2NS_SCALE_FACTOR
;
59 #if defined(CONFIG_CYCLES_CLOCKSOURCE)
61 static unsigned long cycles_cyc2ns_scale
;
63 static notrace cycle_t
bfin_read_cycles(struct clocksource
*cs
)
65 return __bfin_cycles_off
+ (get_cycles() << __bfin_cycles_mod
);
68 static struct clocksource bfin_cs_cycles
= {
69 .name
= "bfin_cs_cycles",
71 .read
= bfin_read_cycles
,
72 .mask
= CLOCKSOURCE_MASK(64),
74 .flags
= CLOCK_SOURCE_IS_CONTINUOUS
,
77 static inline unsigned long long bfin_cs_cycles_sched_clock(void)
79 return cycles_2_ns(bfin_read_cycles(&bfin_cs_cycles
), cycles_cyc2ns_scale
);
82 static int __init
bfin_cs_cycles_init(void)
84 cycles_cyc2ns_scale
= cyc2ns_scale(get_cclk() / 1000);
86 bfin_cs_cycles
.mult
= \
87 clocksource_hz2mult(get_cclk(), bfin_cs_cycles
.shift
);
89 if (clocksource_register(&bfin_cs_cycles
))
90 panic("failed to register clocksource");
95 # define bfin_cs_cycles_init()
98 #ifdef CONFIG_GPTMR0_CLOCKSOURCE
100 unsigned long gptimer0_cyc2ns_scale
;
102 void __init
setup_gptimer0(void)
104 disable_gptimers(TIMER0bit
);
106 set_gptimer_config(TIMER0_id
, \
107 TIMER_OUT_DIS
| TIMER_PERIOD_CNT
| TIMER_MODE_PWM
);
108 set_gptimer_period(TIMER0_id
, -1);
109 set_gptimer_pwidth(TIMER0_id
, -2);
111 enable_gptimers(TIMER0bit
);
114 static cycle_t
bfin_read_gptimer0(struct clocksource
*cs
)
116 return bfin_read_TIMER0_COUNTER();
119 static struct clocksource bfin_cs_gptimer0
= {
120 .name
= "bfin_cs_gptimer0",
122 .read
= bfin_read_gptimer0
,
123 .mask
= CLOCKSOURCE_MASK(32),
125 .flags
= CLOCK_SOURCE_IS_CONTINUOUS
,
128 static inline unsigned long long bfin_cs_gptimer0_sched_clock(void)
130 return cycles_2_ns(bfin_read_TIMER0_COUNTER(), gptimer0_cyc2ns_scale
);
133 static int __init
bfin_cs_gptimer0_init(void)
135 gptimer0_cyc2ns_scale
= cyc2ns_scale(get_sclk() / 1000);
139 bfin_cs_gptimer0
.mult
= \
140 clocksource_hz2mult(get_sclk(), bfin_cs_gptimer0
.shift
);
142 if (clocksource_register(&bfin_cs_gptimer0
))
143 panic("failed to register clocksource");
148 # define bfin_cs_gptimer0_init()
152 #if defined(CONFIG_GPTMR0_CLOCKSOURCE) || defined(CONFIG_CYCLES_CLOCKSOURCE)
153 /* prefer to use cycles since it has higher rating */
154 notrace
unsigned long long sched_clock(void)
156 #if defined(CONFIG_CYCLES_CLOCKSOURCE)
157 return bfin_cs_cycles_sched_clock();
159 return bfin_cs_gptimer0_sched_clock();
164 #ifdef CONFIG_CORE_TIMER_IRQ_L1
165 __attribute__((l1_text
))
167 irqreturn_t
timer_interrupt(int irq
, void *dev_id
);
169 static int bfin_timer_set_next_event(unsigned long, \
170 struct clock_event_device
*);
172 static void bfin_timer_set_mode(enum clock_event_mode
, \
173 struct clock_event_device
*);
175 static struct clock_event_device clockevent_bfin
= {
176 #if defined(CONFIG_TICKSOURCE_GPTMR0)
177 .name
= "bfin_gptimer0",
181 .name
= "bfin_core_timer",
186 .features
= CLOCK_EVT_FEAT_PERIODIC
| CLOCK_EVT_FEAT_ONESHOT
,
187 .set_next_event
= bfin_timer_set_next_event
,
188 .set_mode
= bfin_timer_set_mode
,
191 static struct irqaction bfin_timer_irq
= {
192 #if defined(CONFIG_TICKSOURCE_GPTMR0)
193 .name
= "Blackfin GPTimer0",
195 .name
= "Blackfin CoreTimer",
197 .flags
= IRQF_DISABLED
| IRQF_TIMER
| \
198 IRQF_IRQPOLL
| IRQF_PERCPU
,
199 .handler
= timer_interrupt
,
200 .dev_id
= &clockevent_bfin
,
203 #if defined(CONFIG_TICKSOURCE_GPTMR0)
204 static int bfin_timer_set_next_event(unsigned long cycles
,
205 struct clock_event_device
*evt
)
207 disable_gptimers(TIMER0bit
);
209 /* it starts counting three SCLK cycles after the TIMENx bit is set */
210 set_gptimer_pwidth(TIMER0_id
, cycles
- 3);
211 enable_gptimers(TIMER0bit
);
215 static void bfin_timer_set_mode(enum clock_event_mode mode
,
216 struct clock_event_device
*evt
)
219 case CLOCK_EVT_MODE_PERIODIC
: {
220 set_gptimer_config(TIMER0_id
, \
221 TIMER_OUT_DIS
| TIMER_IRQ_ENA
| \
222 TIMER_PERIOD_CNT
| TIMER_MODE_PWM
);
223 set_gptimer_period(TIMER0_id
, get_sclk() / HZ
);
224 set_gptimer_pwidth(TIMER0_id
, get_sclk() / HZ
- 1);
225 enable_gptimers(TIMER0bit
);
228 case CLOCK_EVT_MODE_ONESHOT
:
229 disable_gptimers(TIMER0bit
);
230 set_gptimer_config(TIMER0_id
, \
231 TIMER_OUT_DIS
| TIMER_IRQ_ENA
| TIMER_MODE_PWM
);
232 set_gptimer_period(TIMER0_id
, 0);
234 case CLOCK_EVT_MODE_UNUSED
:
235 case CLOCK_EVT_MODE_SHUTDOWN
:
236 disable_gptimers(TIMER0bit
);
238 case CLOCK_EVT_MODE_RESUME
:
243 static void bfin_timer_ack(void)
245 set_gptimer_status(TIMER_GROUP1
, TIMER_STATUS_TIMIL0
);
248 static void __init
bfin_timer_init(void)
250 disable_gptimers(TIMER0bit
);
253 static unsigned long __init
bfin_clockevent_check(void)
255 setup_irq(IRQ_TIMER0
, &bfin_timer_irq
);
259 #else /* CONFIG_TICKSOURCE_CORETMR */
261 static int bfin_timer_set_next_event(unsigned long cycles
,
262 struct clock_event_device
*evt
)
264 bfin_write_TCNTL(TMPWR
);
266 bfin_write_TCOUNT(cycles
);
268 bfin_write_TCNTL(TMPWR
| TMREN
);
272 static void bfin_timer_set_mode(enum clock_event_mode mode
,
273 struct clock_event_device
*evt
)
276 case CLOCK_EVT_MODE_PERIODIC
: {
277 unsigned long tcount
= ((get_cclk() / (HZ
* TIME_SCALE
)) - 1);
278 bfin_write_TCNTL(TMPWR
);
280 bfin_write_TSCALE(TIME_SCALE
- 1);
281 bfin_write_TPERIOD(tcount
);
282 bfin_write_TCOUNT(tcount
);
284 bfin_write_TCNTL(TMPWR
| TMREN
| TAUTORLD
);
287 case CLOCK_EVT_MODE_ONESHOT
:
288 bfin_write_TCNTL(TMPWR
);
290 bfin_write_TSCALE(TIME_SCALE
- 1);
291 bfin_write_TPERIOD(0);
292 bfin_write_TCOUNT(0);
294 case CLOCK_EVT_MODE_UNUSED
:
295 case CLOCK_EVT_MODE_SHUTDOWN
:
299 case CLOCK_EVT_MODE_RESUME
:
304 static void bfin_timer_ack(void)
308 static void __init
bfin_timer_init(void)
310 /* power up the timer, but don't enable it just yet */
311 bfin_write_TCNTL(TMPWR
);
315 * the TSCALE prescaler counter.
317 bfin_write_TSCALE(TIME_SCALE
- 1);
318 bfin_write_TPERIOD(0);
319 bfin_write_TCOUNT(0);
324 static unsigned long __init
bfin_clockevent_check(void)
326 setup_irq(IRQ_CORETMR
, &bfin_timer_irq
);
327 return get_cclk() / TIME_SCALE
;
330 void __init
setup_core_timer(void)
333 bfin_timer_set_mode(CLOCK_EVT_MODE_PERIODIC
, NULL
);
335 #endif /* CONFIG_TICKSOURCE_GPTMR0 */
338 * timer_interrupt() needs to keep up the real-time clock,
339 * as well as call the "do_timer()" routine every clocktick
341 irqreturn_t
timer_interrupt(int irq
, void *dev_id
)
343 struct clock_event_device
*evt
= dev_id
;
345 evt
->event_handler(evt
);
350 static int __init
bfin_clockevent_init(void)
352 unsigned long timer_clk
;
354 timer_clk
= bfin_clockevent_check();
358 clockevent_bfin
.mult
= div_sc(timer_clk
, NSEC_PER_SEC
, clockevent_bfin
.shift
);
359 clockevent_bfin
.max_delta_ns
= clockevent_delta2ns(-1, &clockevent_bfin
);
360 clockevent_bfin
.min_delta_ns
= clockevent_delta2ns(100, &clockevent_bfin
);
361 clockevent_bfin
.cpumask
= cpumask_of(0);
362 clockevents_register_device(&clockevent_bfin
);
367 void __init
time_init(void)
369 time_t secs_since_1970
= (365 * 37 + 9) * 24 * 60 * 60; /* 1 Jan 2007 */
371 #ifdef CONFIG_RTC_DRV_BFIN
372 /* [#2663] hack to filter junk RTC values that would cause
373 * userspace to have to deal with time values greater than
374 * 2^31 seconds (which uClibc cannot cope with yet)
376 if ((bfin_read_RTC_STAT() & 0xC0000000) == 0xC0000000) {
377 printk(KERN_NOTICE
"bfin-rtc: invalid date; resetting\n");
378 bfin_write_RTC_STAT(0);
382 /* Initialize xtime. From now on, xtime is updated with timer interrupts */
383 xtime
.tv_sec
= secs_since_1970
;
385 set_normalized_timespec(&wall_to_monotonic
, -xtime
.tv_sec
, -xtime
.tv_nsec
);
387 bfin_cs_cycles_init();
388 bfin_cs_gptimer0_init();
389 bfin_clockevent_init();