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git.proxmox.com Git - mirror_ubuntu-jammy-kernel.git/blob - arch/blackfin/kernel/time.c
2 * arch/blackfin/kernel/time.c
4 * This file contains the Blackfin-specific time handling details.
5 * Most of the stuff is located in the machine specific files.
7 * Copyright 2004-2008 Analog Devices Inc.
8 * Licensed under the GPL-2 or later.
11 #include <linux/module.h>
12 #include <linux/profile.h>
13 #include <linux/interrupt.h>
14 #include <linux/time.h>
15 #include <linux/irq.h>
16 #include <linux/delay.h>
18 #include <asm/blackfin.h>
20 #include <asm/gptimers.h>
22 /* This is an NTP setting */
23 #define TICK_SIZE (tick_nsec / 1000)
25 static struct irqaction bfin_timer_irq
= {
26 .name
= "Blackfin Timer Tick",
27 #ifdef CONFIG_IRQ_PER_CPU
28 .flags
= IRQF_DISABLED
| IRQF_PERCPU
,
30 .flags
= IRQF_DISABLED
34 #if defined(CONFIG_TICK_SOURCE_SYSTMR0) || defined(CONFIG_IPIPE)
35 void __init
setup_system_timer0(void)
37 /* Power down the core timer, just to play safe. */
40 disable_gptimers(TIMER0bit
);
41 set_gptimer_status(0, TIMER_STATUS_TRUN0
);
42 while (get_gptimer_status(0) & TIMER_STATUS_TRUN0
)
45 set_gptimer_config(0, 0x59); /* IRQ enable, periodic, PWM_OUT, SCLKed, OUT PAD disabled */
46 set_gptimer_period(TIMER0_id
, get_sclk() / HZ
);
47 set_gptimer_pwidth(TIMER0_id
, 1);
49 enable_gptimers(TIMER0bit
);
52 void __init
setup_core_timer(void)
56 /* power up the timer, but don't enable it just yet */
60 /* the TSCALE prescaler counter */
61 bfin_write_TSCALE(TIME_SCALE
- 1);
63 tcount
= ((get_cclk() / (HZ
* TIME_SCALE
)) - 1);
64 bfin_write_TPERIOD(tcount
);
65 bfin_write_TCOUNT(tcount
);
67 /* now enable the timer */
75 time_sched_init(irqreturn_t(*timer_routine
) (int, void *))
77 #if defined(CONFIG_TICK_SOURCE_SYSTMR0) || defined(CONFIG_IPIPE)
78 setup_system_timer0();
79 bfin_timer_irq
.handler
= timer_routine
;
80 setup_irq(IRQ_TIMER0
, &bfin_timer_irq
);
83 bfin_timer_irq
.handler
= timer_routine
;
84 setup_irq(IRQ_CORETMR
, &bfin_timer_irq
);
89 * Should return useconds since last timer tick
91 #ifndef CONFIG_GENERIC_TIME
92 static unsigned long gettimeoffset(void)
95 unsigned long clocks_per_jiffy
;
97 #if defined(CONFIG_TICK_SOURCE_SYSTMR0) || defined(CONFIG_IPIPE)
98 clocks_per_jiffy
= bfin_read_TIMER0_PERIOD();
99 offset
= bfin_read_TIMER0_COUNTER() / \
100 (((clocks_per_jiffy
+ 1) * HZ
) / USEC_PER_SEC
);
102 if ((get_gptimer_status(0) & TIMER_STATUS_TIMIL0
) && offset
< (100000 / HZ
/ 2))
103 offset
+= (USEC_PER_SEC
/ HZ
);
105 clocks_per_jiffy
= bfin_read_TPERIOD();
106 offset
= (clocks_per_jiffy
- bfin_read_TCOUNT()) / \
107 (((clocks_per_jiffy
+ 1) * HZ
) / USEC_PER_SEC
);
109 /* Check if we just wrapped the counters and maybe missed a tick */
110 if ((bfin_read_ILAT() & (1 << IRQ_CORETMR
))
111 && (offset
< (100000 / HZ
/ 2)))
112 offset
+= (USEC_PER_SEC
/ HZ
);
118 static inline int set_rtc_mmss(unsigned long nowtime
)
124 * timer_interrupt() needs to keep up the real-time clock,
125 * as well as call the "do_timer()" routine every clocktick
127 #ifdef CONFIG_CORE_TIMER_IRQ_L1
128 __attribute__((l1_text
))
130 irqreturn_t
timer_interrupt(int irq
, void *dummy
)
132 /* last time the cmos clock got updated */
133 static long last_rtc_update
;
135 write_seqlock(&xtime_lock
);
136 #if defined(CONFIG_TICK_SOURCE_SYSTMR0) && !defined(CONFIG_IPIPE)
137 /* FIXME: Here TIMIL0 is not set when IPIPE enabled, why? */
138 if (get_gptimer_status(0) & TIMER_STATUS_TIMIL0
) {
143 * If we have an externally synchronized Linux clock, then update
144 * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
145 * called as close as possible to 500 ms before the new second starts.
148 xtime
.tv_sec
> last_rtc_update
+ 660 &&
149 (xtime
.tv_nsec
/ NSEC_PER_USEC
) >=
150 500000 - ((unsigned)TICK_SIZE
) / 2
151 && (xtime
.tv_nsec
/ NSEC_PER_USEC
) <=
152 500000 + ((unsigned)TICK_SIZE
) / 2) {
153 if (set_rtc_mmss(xtime
.tv_sec
) == 0)
154 last_rtc_update
= xtime
.tv_sec
;
156 /* Do it again in 60s. */
157 last_rtc_update
= xtime
.tv_sec
- 600;
159 #if defined(CONFIG_TICK_SOURCE_SYSTMR0) && !defined(CONFIG_IPIPE)
160 set_gptimer_status(0, TIMER_STATUS_TIMIL0
);
163 write_sequnlock(&xtime_lock
);
166 update_root_process_times(get_irq_regs());
168 update_process_times(user_mode(get_irq_regs()));
170 profile_tick(CPU_PROFILING
);
175 void __init
time_init(void)
177 time_t secs_since_1970
= (365 * 37 + 9) * 24 * 60 * 60; /* 1 Jan 2007 */
179 #ifdef CONFIG_RTC_DRV_BFIN
180 /* [#2663] hack to filter junk RTC values that would cause
181 * userspace to have to deal with time values greater than
182 * 2^31 seconds (which uClibc cannot cope with yet)
184 if ((bfin_read_RTC_STAT() & 0xC0000000) == 0xC0000000) {
185 printk(KERN_NOTICE
"bfin-rtc: invalid date; resetting\n");
186 bfin_write_RTC_STAT(0);
190 /* Initialize xtime. From now on, xtime is updated with timer interrupts */
191 xtime
.tv_sec
= secs_since_1970
;
194 wall_to_monotonic
.tv_sec
= -xtime
.tv_sec
;
196 time_sched_init(timer_interrupt
);
199 #ifndef CONFIG_GENERIC_TIME
200 void do_gettimeofday(struct timeval
*tv
)
204 unsigned long usec
, sec
;
207 seq
= read_seqbegin_irqsave(&xtime_lock
, flags
);
208 usec
= gettimeoffset();
210 usec
+= (xtime
.tv_nsec
/ NSEC_PER_USEC
);
212 while (read_seqretry_irqrestore(&xtime_lock
, seq
, flags
));
214 while (usec
>= USEC_PER_SEC
) {
215 usec
-= USEC_PER_SEC
;
222 EXPORT_SYMBOL(do_gettimeofday
);
224 int do_settimeofday(struct timespec
*tv
)
226 time_t wtm_sec
, sec
= tv
->tv_sec
;
227 long wtm_nsec
, nsec
= tv
->tv_nsec
;
229 if ((unsigned long)tv
->tv_nsec
>= NSEC_PER_SEC
)
232 write_seqlock_irq(&xtime_lock
);
234 * This is revolting. We need to set the xtime.tv_usec
235 * correctly. However, the value in this location is
236 * is value at the last tick.
237 * Discover what correction gettimeofday
238 * would have done, and then undo it!
240 nsec
-= (gettimeoffset() * NSEC_PER_USEC
);
242 wtm_sec
= wall_to_monotonic
.tv_sec
+ (xtime
.tv_sec
- sec
);
243 wtm_nsec
= wall_to_monotonic
.tv_nsec
+ (xtime
.tv_nsec
- nsec
);
245 set_normalized_timespec(&xtime
, sec
, nsec
);
246 set_normalized_timespec(&wall_to_monotonic
, wtm_sec
, wtm_nsec
);
250 write_sequnlock_irq(&xtime_lock
);
255 EXPORT_SYMBOL(do_settimeofday
);
256 #endif /* !CONFIG_GENERIC_TIME */
259 * Scheduler clock - returns current time in nanosec units.
261 unsigned long long sched_clock(void)
263 return (unsigned long long)jiffies
*(NSEC_PER_SEC
/ HZ
);