--- /dev/null
+/* $Id: time.c,v 1.19 2005/04/29 05:40:09 starvik Exp $
+ *
+ * linux/arch/cris/arch-v32/kernel/time.c
+ *
+ * Copyright (C) 2003 Axis Communications AB
+ *
+ */
+
+#include <linux/config.h>
+#include <linux/timex.h>
+#include <linux/time.h>
+#include <linux/jiffies.h>
+#include <linux/interrupt.h>
+#include <linux/swap.h>
+#include <linux/sched.h>
+#include <linux/init.h>
+#include <linux/threads.h>
+#include <asm/types.h>
+#include <asm/signal.h>
+#include <asm/io.h>
+#include <asm/delay.h>
+#include <asm/rtc.h>
+#include <asm/irq.h>
+
+#include <asm/arch/hwregs/reg_map.h>
+#include <asm/arch/hwregs/reg_rdwr.h>
+#include <asm/arch/hwregs/timer_defs.h>
+#include <asm/arch/hwregs/intr_vect_defs.h>
+
+/* Watchdog defines */
+#define ETRAX_WD_KEY_MASK 0x7F /* key is 7 bit */
+#define ETRAX_WD_HZ 763 /* watchdog counts at 763 Hz */
+#define ETRAX_WD_CNT ((2*ETRAX_WD_HZ)/HZ + 1) /* Number of 763 counts before watchdog bites */
+
+unsigned long timer_regs[NR_CPUS] =
+{
+ regi_timer,
+#ifdef CONFIG_SMP
+ regi_timer2
+#endif
+};
+
+extern void update_xtime_from_cmos(void);
+extern int set_rtc_mmss(unsigned long nowtime);
+extern int setup_irq(int, struct irqaction *);
+extern int have_rtc;
+
+unsigned long get_ns_in_jiffie(void)
+{
+ reg_timer_r_tmr0_data data;
+ unsigned long ns;
+
+ data = REG_RD(timer, regi_timer, r_tmr0_data);
+ ns = (TIMER0_DIV - data) * 10;
+ return ns;
+}
+
+unsigned long do_slow_gettimeoffset(void)
+{
+ unsigned long count;
+ unsigned long usec_count = 0;
+
+ static unsigned long count_p = TIMER0_DIV;/* for the first call after boot */
+ static unsigned long jiffies_p = 0;
+
+ /*
+ * cache volatile jiffies temporarily; we have IRQs turned off.
+ */
+ unsigned long jiffies_t;
+
+ /* The timer interrupt comes from Etrax timer 0. In order to get
+ * better precision, we check the current value. It might have
+ * underflowed already though.
+ */
+
+ count = REG_RD(timer, regi_timer, r_tmr0_data);
+ jiffies_t = jiffies;
+
+ /*
+ * avoiding timer inconsistencies (they are rare, but they happen)...
+ * there are one problem that must be avoided here:
+ * 1. the timer counter underflows
+ */
+ if( jiffies_t == jiffies_p ) {
+ if( count > count_p ) {
+ /* Timer wrapped, use new count and prescale
+ * increase the time corresponding to one jiffie
+ */
+ usec_count = 1000000/HZ;
+ }
+ } else
+ jiffies_p = jiffies_t;
+ count_p = count;
+ /* Convert timer value to usec */
+ /* 100 MHz timer, divide by 100 to get usec */
+ usec_count += (TIMER0_DIV - count) / 100;
+ return usec_count;
+}
+
+/* From timer MDS describing the hardware watchdog:
+ * 4.3.1 Watchdog Operation
+ * The watchdog timer is an 8-bit timer with a configurable start value.
+ * Once started the whatchdog counts downwards with a frequency of 763 Hz
+ * (100/131072 MHz). When the watchdog counts down to 1, it generates an
+ * NMI (Non Maskable Interrupt), and when it counts down to 0, it resets the
+ * chip.
+ */
+/* This gives us 1.3 ms to do something useful when the NMI comes */
+
+/* right now, starting the watchdog is the same as resetting it */
+#define start_watchdog reset_watchdog
+
+#if defined(CONFIG_ETRAX_WATCHDOG)
+static short int watchdog_key = 42; /* arbitrary 7 bit number */
+#endif
+
+/* number of pages to consider "out of memory". it is normal that the memory
+ * is used though, so put this really low.
+ */
+
+#define WATCHDOG_MIN_FREE_PAGES 8
+
+void
+reset_watchdog(void)
+{
+#if defined(CONFIG_ETRAX_WATCHDOG)
+ reg_timer_rw_wd_ctrl wd_ctrl = { 0 };
+
+ /* only keep watchdog happy as long as we have memory left! */
+ if(nr_free_pages() > WATCHDOG_MIN_FREE_PAGES) {
+ /* reset the watchdog with the inverse of the old key */
+ watchdog_key ^= ETRAX_WD_KEY_MASK; /* invert key, which is 7 bits */
+ wd_ctrl.cnt = ETRAX_WD_CNT;
+ wd_ctrl.cmd = regk_timer_start;
+ wd_ctrl.key = watchdog_key;
+ REG_WR(timer, regi_timer, rw_wd_ctrl, wd_ctrl);
+ }
+#endif
+}
+
+/* stop the watchdog - we still need the correct key */
+
+void
+stop_watchdog(void)
+{
+#if defined(CONFIG_ETRAX_WATCHDOG)
+ reg_timer_rw_wd_ctrl wd_ctrl = { 0 };
+ watchdog_key ^= ETRAX_WD_KEY_MASK; /* invert key, which is 7 bits */
+ wd_ctrl.cnt = ETRAX_WD_CNT;
+ wd_ctrl.cmd = regk_timer_stop;
+ wd_ctrl.key = watchdog_key;
+ REG_WR(timer, regi_timer, rw_wd_ctrl, wd_ctrl);
+#endif
+}
+
+extern void show_registers(struct pt_regs *regs);
+
+void
+handle_watchdog_bite(struct pt_regs* regs)
+{
+#if defined(CONFIG_ETRAX_WATCHDOG)
+ extern int cause_of_death;
+
+ raw_printk("Watchdog bite\n");
+
+ /* Check if forced restart or unexpected watchdog */
+ if (cause_of_death == 0xbedead) {
+ while(1);
+ }
+
+ /* Unexpected watchdog, stop the watchdog and dump registers*/
+ stop_watchdog();
+ raw_printk("Oops: bitten by watchdog\n");
+ show_registers(regs);
+#ifndef CONFIG_ETRAX_WATCHDOG_NICE_DOGGY
+ reset_watchdog();
+#endif
+ while(1) /* nothing */;
+#endif
+}
+
+/* last time the cmos clock got updated */
+static long last_rtc_update = 0;
+
+/*
+ * timer_interrupt() needs to keep up the real-time clock,
+ * as well as call the "do_timer()" routine every clocktick
+ */
+
+//static unsigned short myjiff; /* used by our debug routine print_timestamp */
+
+extern void cris_do_profile(struct pt_regs *regs);
+
+static inline irqreturn_t
+timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+{
+ int cpu = smp_processor_id();
+ reg_timer_r_masked_intr masked_intr;
+ reg_timer_rw_ack_intr ack_intr = { 0 };
+
+ /* Check if the timer interrupt is for us (a tmr0 int) */
+ masked_intr = REG_RD(timer, timer_regs[cpu], r_masked_intr);
+ if (!masked_intr.tmr0)
+ return IRQ_NONE;
+
+ /* acknowledge the timer irq */
+ ack_intr.tmr0 = 1;
+ REG_WR(timer, timer_regs[cpu], rw_ack_intr, ack_intr);
+
+ /* reset watchdog otherwise it resets us! */
+ reset_watchdog();
+
+ /* Update statistics. */
+ update_process_times(user_mode(regs));
+
+ cris_do_profile(regs); /* Save profiling information */
+
+ /* The master CPU is responsible for the time keeping. */
+ if (cpu != 0)
+ return IRQ_HANDLED;
+
+ /* call the real timer interrupt handler */
+ do_timer(regs);
+
+ /*
+ * 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.
+ *
+ * The division here is not time critical since it will run once in
+ * 11 minutes
+ */
+ if ((time_status & STA_UNSYNC) == 0 &&
+ xtime.tv_sec > last_rtc_update + 660 &&
+ (xtime.tv_nsec / 1000) >= 500000 - (tick_nsec / 1000) / 2 &&
+ (xtime.tv_nsec / 1000) <= 500000 + (tick_nsec / 1000) / 2) {
+ if (set_rtc_mmss(xtime.tv_sec) == 0)
+ last_rtc_update = xtime.tv_sec;
+ else
+ last_rtc_update = xtime.tv_sec - 600; /* do it again in 60 s */
+ }
+ return IRQ_HANDLED;
+}
+
+/* timer is SA_SHIRQ so drivers can add stuff to the timer irq chain
+ * it needs to be SA_INTERRUPT to make the jiffies update work properly
+ */
+
+static struct irqaction irq_timer = { timer_interrupt, SA_SHIRQ | SA_INTERRUPT,
+ CPU_MASK_NONE, "timer", NULL, NULL};
+
+void __init
+cris_timer_init(void)
+{
+ int cpu = smp_processor_id();
+ reg_timer_rw_tmr0_ctrl tmr0_ctrl = { 0 };
+ reg_timer_rw_tmr0_div tmr0_div = TIMER0_DIV;
+ reg_timer_rw_intr_mask timer_intr_mask;
+
+ /* Setup the etrax timers
+ * Base frequency is 100MHz, divider 1000000 -> 100 HZ
+ * We use timer0, so timer1 is free.
+ * The trig timer is used by the fasttimer API if enabled.
+ */
+
+ tmr0_ctrl.op = regk_timer_ld;
+ tmr0_ctrl.freq = regk_timer_f100;
+ REG_WR(timer, timer_regs[cpu], rw_tmr0_div, tmr0_div);
+ REG_WR(timer, timer_regs[cpu], rw_tmr0_ctrl, tmr0_ctrl); /* Load */
+ tmr0_ctrl.op = regk_timer_run;
+ REG_WR(timer, timer_regs[cpu], rw_tmr0_ctrl, tmr0_ctrl); /* Start */
+
+ /* enable the timer irq */
+ timer_intr_mask = REG_RD(timer, timer_regs[cpu], rw_intr_mask);
+ timer_intr_mask.tmr0 = 1;
+ REG_WR(timer, timer_regs[cpu], rw_intr_mask, timer_intr_mask);
+}
+
+void __init
+time_init(void)
+{
+ reg_intr_vect_rw_mask intr_mask;
+
+ /* probe for the RTC and read it if it exists
+ * Before the RTC can be probed the loops_per_usec variable needs
+ * to be initialized to make usleep work. A better value for
+ * loops_per_usec is calculated by the kernel later once the
+ * clock has started.
+ */
+ loops_per_usec = 50;
+
+ if(RTC_INIT() < 0) {
+ /* no RTC, start at 1980 */
+ xtime.tv_sec = 0;
+ xtime.tv_nsec = 0;
+ have_rtc = 0;
+ } else {
+ /* get the current time */
+ have_rtc = 1;
+ update_xtime_from_cmos();
+ }
+
+ /*
+ * Initialize wall_to_monotonic such that adding it to xtime will yield zero, the
+ * tv_nsec field must be normalized (i.e., 0 <= nsec < NSEC_PER_SEC).
+ */
+ set_normalized_timespec(&wall_to_monotonic, -xtime.tv_sec, -xtime.tv_nsec);
+
+ /* Start CPU local timer */
+ cris_timer_init();
+
+ /* enable the timer irq in global config */
+ intr_mask = REG_RD(intr_vect, regi_irq, rw_mask);
+ intr_mask.timer = 1;
+ REG_WR(intr_vect, regi_irq, rw_mask, intr_mask);
+
+ /* now actually register the timer irq handler that calls timer_interrupt() */
+
+ setup_irq(TIMER_INTR_VECT, &irq_timer);
+
+ /* enable watchdog if we should use one */
+
+#if defined(CONFIG_ETRAX_WATCHDOG)
+ printk("Enabling watchdog...\n");
+ start_watchdog();
+
+ /* If we use the hardware watchdog, we want to trap it as an NMI
+ and dump registers before it resets us. For this to happen, we
+ must set the "m" NMI enable flag (which once set, is unset only
+ when an NMI is taken).
+
+ The same goes for the external NMI, but that doesn't have any
+ driver or infrastructure support yet. */
+ {
+ unsigned long flags;
+ local_save_flags(flags);
+ flags |= (1<<30); /* NMI M flag is at bit 30 */
+ local_irq_restore(flags);
+ }
+#endif
+}
git.openpandora.org / pandora-kernel.git / blobdiff