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Diffstat (limited to 'arch/blackfin/kernel/time.c')
| -rw-r--r-- | arch/blackfin/kernel/time.c | 326 |
1 files changed, 326 insertions, 0 deletions
diff --git a/arch/blackfin/kernel/time.c b/arch/blackfin/kernel/time.c new file mode 100644 index 00000000000..f578176b6d9 --- /dev/null +++ b/arch/blackfin/kernel/time.c @@ -0,0 +1,326 @@ +/* + * File: arch/blackfin/kernel/time.c + * Based on: none - original work + * Author: + * + * Created: + * Description: This file contains the bfin-specific time handling details. + * Most of the stuff is located in the machine specific files. + * + * Modified: + * Copyright 2004-2006 Analog Devices Inc. + * + * Bugs: Enter bugs at http://blackfin.uclinux.org/ + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, see the file COPYING, or write + * to the Free Software Foundation, Inc., + * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#include <linux/module.h> +#include <linux/profile.h> +#include <linux/interrupt.h> +#include <linux/time.h> +#include <linux/irq.h> + +#include <asm/blackfin.h> + +/* This is an NTP setting */ +#define TICK_SIZE (tick_nsec / 1000) + +static void time_sched_init(irqreturn_t(*timer_routine) + (int, void *)); +static unsigned long gettimeoffset(void); +static inline void do_leds(void); + +#if (defined(CONFIG_BFIN_ALIVE_LED) || defined(CONFIG_BFIN_IDLE_LED)) +void __init init_leds(void) +{ + unsigned int tmp = 0; + +#if defined(CONFIG_BFIN_ALIVE_LED) + /* config pins as output. */ + tmp = bfin_read_CONFIG_BFIN_ALIVE_LED_DPORT(); + SSYNC(); + bfin_write_CONFIG_BFIN_ALIVE_LED_DPORT(tmp | CONFIG_BFIN_ALIVE_LED_PIN); + SSYNC(); + + /* First set led be off */ + tmp = bfin_read_CONFIG_BFIN_ALIVE_LED_PORT(); + SSYNC(); + bfin_write_CONFIG_BFIN_ALIVE_LED_PORT(tmp | CONFIG_BFIN_ALIVE_LED_PIN); /* light off */ + SSYNC(); +#endif + +#if defined(CONFIG_BFIN_IDLE_LED) + /* config pins as output. */ + tmp = bfin_read_CONFIG_BFIN_IDLE_LED_DPORT(); + SSYNC(); + bfin_write_CONFIG_BFIN_IDLE_LED_DPORT(tmp | CONFIG_BFIN_IDLE_LED_PIN); + SSYNC(); + + /* First set led be off */ + tmp = bfin_read_CONFIG_BFIN_IDLE_LED_PORT(); + SSYNC(); + bfin_write_CONFIG_BFIN_IDLE_LED_PORT(tmp | CONFIG_BFIN_IDLE_LED_PIN); /* light off */ + SSYNC(); +#endif +} +#else +void __init init_leds(void) +{ +} +#endif + +#if defined(CONFIG_BFIN_ALIVE_LED) +static inline void do_leds(void) +{ + static unsigned int count = 50; + static int flag = 0; + unsigned short tmp = 0; + + if (--count == 0) { + count = 50; + flag = ~flag; + } + tmp = bfin_read_CONFIG_BFIN_ALIVE_LED_PORT(); + SSYNC(); + + if (flag) + tmp &= ~CONFIG_BFIN_ALIVE_LED_PIN; /* light on */ + else + tmp |= CONFIG_BFIN_ALIVE_LED_PIN; /* light off */ + + bfin_write_CONFIG_BFIN_ALIVE_LED_PORT(tmp); + SSYNC(); + +} +#else +static inline void do_leds(void) +{ +} +#endif + +static struct irqaction bfin_timer_irq = { + .name = "BFIN Timer Tick", + .flags = IRQF_DISABLED +}; + +/* + * The way that the Blackfin core timer works is: + * - CCLK is divided by a programmable 8-bit pre-scaler (TSCALE) + * - Every time TSCALE ticks, a 32bit is counted down (TCOUNT) + * + * If you take the fastest clock (1ns, or 1GHz to make the math work easier) + * 10ms is 10,000,000 clock ticks, which fits easy into a 32-bit counter + * (32 bit counter is 4,294,967,296ns or 4.2 seconds) so, we don't need + * to use TSCALE, and program it to zero (which is pass CCLK through). + * If you feel like using it, try to keep HZ * TIMESCALE to some + * value that divides easy (like power of 2). + */ + +#define TIME_SCALE 1 + +static void +time_sched_init(irqreturn_t(*timer_routine) (int, void *)) +{ + u32 tcount; + + /* power up the timer, but don't enable it just yet */ + bfin_write_TCNTL(1); + CSYNC(); + + /* + * the TSCALE prescaler counter. + */ + bfin_write_TSCALE((TIME_SCALE - 1)); + + tcount = ((get_cclk() / (HZ * TIME_SCALE)) - 1); + bfin_write_TPERIOD(tcount); + bfin_write_TCOUNT(tcount); + + /* now enable the timer */ + CSYNC(); + + bfin_write_TCNTL(7); + + bfin_timer_irq.handler = (irq_handler_t)timer_routine; + /* call setup_irq instead of request_irq because request_irq calls + * kmalloc which has not been initialized yet + */ + setup_irq(IRQ_CORETMR, &bfin_timer_irq); +} + +/* + * Should return useconds since last timer tick + */ +static unsigned long gettimeoffset(void) +{ + unsigned long offset; + unsigned long clocks_per_jiffy; + + clocks_per_jiffy = bfin_read_TPERIOD(); + offset = + (clocks_per_jiffy - + bfin_read_TCOUNT()) / (((clocks_per_jiffy + 1) * HZ) / + USEC_PER_SEC); + + /* Check if we just wrapped the counters and maybe missed a tick */ + if ((bfin_read_ILAT() & (1 << IRQ_CORETMR)) + && (offset < (100000 / HZ / 2))) + offset += (USEC_PER_SEC / HZ); + + return offset; +} + +static inline int set_rtc_mmss(unsigned long nowtime) +{ + return 0; +} + +/* + * timer_interrupt() needs to keep up the real-time clock, + * as well as call the "do_timer()" routine every clocktick + */ +#ifdef CONFIG_CORE_TIMER_IRQ_L1 +irqreturn_t timer_interrupt(int irq, void *dummy)__attribute__((l1_text)); +#endif + +irqreturn_t timer_interrupt(int irq, void *dummy) +{ + /* last time the cmos clock got updated */ + static long last_rtc_update = 0; + + write_seqlock(&xtime_lock); + + do_timer(1); + do_leds(); + +#ifndef CONFIG_SMP + update_process_times(user_mode(get_irq_regs())); +#endif + profile_tick(CPU_PROFILING); + + /* + * If we have an externally synchronized Linux clock, then update + * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be + * called as close as possible to 500 ms before the new second starts. + */ + + if (ntp_synced() && + xtime.tv_sec > last_rtc_update + 660 && + (xtime.tv_nsec / NSEC_PER_USEC) >= + 500000 - ((unsigned)TICK_SIZE) / 2 + && (xtime.tv_nsec / NSEC_PER_USEC) <= + 500000 + ((unsigned)TICK_SIZE) / 2) { + if (set_rtc_mmss(xtime.tv_sec) == 0) + last_rtc_update = xtime.tv_sec; + else + /* Do it again in 60s. */ + last_rtc_update = xtime.tv_sec - 600; + } + write_sequnlock(&xtime_lock); + return IRQ_HANDLED; +} + +void __init time_init(void) +{ + time_t secs_since_1970 = (365 * 37 + 9) * 24 * 60 * 60; /* 1 Jan 2007 */ + +#ifdef CONFIG_RTC_DRV_BFIN + /* [#2663] hack to filter junk RTC values that would cause + * userspace to have to deal with time values greater than + * 2^31 seconds (which uClibc cannot cope with yet) + */ + if ((bfin_read_RTC_STAT() & 0xC0000000) == 0xC0000000) { + printk(KERN_NOTICE "bfin-rtc: invalid date; resetting\n"); + bfin_write_RTC_STAT(0); + } +#endif + + /* Initialize xtime. From now on, xtime is updated with timer interrupts */ + xtime.tv_sec = secs_since_1970; + xtime.tv_nsec = 0; + + wall_to_monotonic.tv_sec = -xtime.tv_sec; + + time_sched_init(timer_interrupt); +} + +#ifndef CONFIG_GENERIC_TIME +void do_gettimeofday(struct timeval *tv) +{ + unsigned long flags; + unsigned long seq; + unsigned long usec, sec; + + do { + seq = read_seqbegin_irqsave(&xtime_lock, flags); + usec = gettimeoffset(); + sec = xtime.tv_sec; + usec += (xtime.tv_nsec / NSEC_PER_USEC); + } + while (read_seqretry_irqrestore(&xtime_lock, seq, flags)); + + while (usec >= USEC_PER_SEC) { + usec -= USEC_PER_SEC; + sec++; + } + + tv->tv_sec = sec; + tv->tv_usec = usec; +} +EXPORT_SYMBOL(do_gettimeofday); + +int do_settimeofday(struct timespec *tv) +{ + time_t wtm_sec, sec = tv->tv_sec; + long wtm_nsec, nsec = tv->tv_nsec; + + if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) + return -EINVAL; + + write_seqlock_irq(&xtime_lock); + /* + * This is revolting. We need to set the xtime.tv_usec + * correctly. However, the value in this location is + * is value at the last tick. + * Discover what correction gettimeofday + * would have done, and then undo it! + */ + nsec -= (gettimeoffset() * NSEC_PER_USEC); + + wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec); + wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec); + + set_normalized_timespec(&xtime, sec, nsec); + set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec); + + ntp_clear(); + + write_sequnlock_irq(&xtime_lock); + clock_was_set(); + + return 0; +} +EXPORT_SYMBOL(do_settimeofday); +#endif /* !CONFIG_GENERIC_TIME */ + +/* + * Scheduler clock - returns current time in nanosec units. + */ +unsigned long long sched_clock(void) +{ + return (unsigned long long)jiffies *(NSEC_PER_SEC / HZ); +} |