patch-2.4.20 linux-2.4.20/arch/mips/sgi-ip27/ip27-timer.c

• Lines: 240
• Date: Thu Nov 28 15:53:10 2002
• Orig file: linux-2.4.19/arch/mips/sgi-ip27/ip27-timer.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -urN linux-2.4.19/arch/mips/sgi-ip27/ip27-timer.c linux-2.4.20/arch/mips/sgi-ip27/ip27-timer.c
@@ -0,0 +1,239 @@
+/*
+ * Copytight (C) 1999, 2000 Ralf Baechle (ralf@gnu.org)
+ * Copytight (C) 1999, 2000 Silicon Graphics, Inc.
+ */
+#include <linux/config.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/interrupt.h>
+#include <linux/kernel_stat.h>
+#include <linux/param.h>
+#include <linux/timex.h>
+#include <linux/mm.h>
+
+#include <asm/time.h>
+#include <asm/pgtable.h>
+#include <asm/sgialib.h>
+#include <asm/sn/ioc3.h>
+#include <asm/m48t35.h>
+#include <asm/sn/klconfig.h>
+#include <asm/sn/arch.h>
+#include <asm/sn/addrs.h>
+#include <asm/sn/sn_private.h>
+#include <asm/sn/sn0/ip27.h>
+#include <asm/sn/sn0/hub.h>
+
+/*
+ * This is a hack; we really need to figure these values out dynamically
+ *
+ * Since 800 ns works very well with various HUB frequencies, such as
+ * 360, 380, 390 and 400 MHZ, we use 800 ns rtc cycle time.
+ *
+ * Ralf: which clock rate is used to feed the counter?
+ */
+#define NSEC_PER_CYCLE		800
+#define NSEC_PER_SEC		1000000000
+#define CYCLES_PER_SEC		(NSEC_PER_SEC/NSEC_PER_CYCLE)
+#define CYCLES_PER_JIFFY	(CYCLES_PER_SEC/HZ)
+
+static unsigned long ct_cur[NR_CPUS];	/* What counter should be at next timer irq */
+static long last_rtc_update;		/* Last time the rtc clock got updated */
+
+extern rwlock_t xtime_lock;
+extern volatile unsigned long wall_jiffies;
+
+
+static int set_rtc_mmss(unsigned long nowtime)
+{
+	int retval = 0;
+	int real_seconds, real_minutes, cmos_minutes;
+	struct m48t35_rtc *rtc;
+	nasid_t nid;
+
+	nid = get_nasid();
+	rtc = (struct m48t35_rtc *)(KL_CONFIG_CH_CONS_INFO(nid)->memory_base +
+							IOC3_BYTEBUS_DEV0);
+
+	rtc->control |= M48T35_RTC_READ;
+	cmos_minutes = rtc->min;
+	BCD_TO_BIN(cmos_minutes);
+	rtc->control &= ~M48T35_RTC_READ;
+
+	/*
+	 * Since we're only adjusting minutes and seconds, don't interfere with
+	 * hour overflow. This avoids messing with unknown time zones but
+	 * requires your RTC not to be off by more than 15 minutes
+	 */
+	real_seconds = nowtime % 60;
+	real_minutes = nowtime / 60;
+	if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1)
+		real_minutes += 30;	/* correct for half hour time zone */
+	real_minutes %= 60;
+
+	if (abs(real_minutes - cmos_minutes) < 30) {
+		BIN_TO_BCD(real_seconds);
+		BIN_TO_BCD(real_minutes);
+		rtc->control |= M48T35_RTC_SET;
+		rtc->sec = real_seconds;
+		rtc->min = real_minutes;
+		rtc->control &= ~M48T35_RTC_SET;
+	} else {
+		printk(KERN_WARNING
+		       "set_rtc_mmss: can't update from %d to %d\n",
+		       cmos_minutes, real_minutes);
+		retval = -1;
+	}
+
+	return retval;
+}
+
+void rt_timer_interrupt(struct pt_regs *regs)
+{
+	int cpu = smp_processor_id();
+	int cpuA = ((cputoslice(cpu)) == 0);
+	int irq = 9;				/* XXX Assign number */
+
+	irq_enter(cpu, irq);
+	write_lock(&xtime_lock);
+
+again:
+	LOCAL_HUB_S(cpuA ? PI_RT_PEND_A : PI_RT_PEND_B, 0);	/* Ack  */
+	ct_cur[cpu] += CYCLES_PER_JIFFY;
+	LOCAL_HUB_S(cpuA ? PI_RT_COMPARE_A : PI_RT_COMPARE_B, ct_cur[cpu]);
+
+	if (LOCAL_HUB_L(PI_RT_COUNT) >= ct_cur[cpu])
+		goto again;
+
+	kstat.irqs[cpu][irq]++;		/* kstat only for bootcpu? */
+
+	if (cpu == 0)
+		do_timer(regs);
+
+#ifdef CONFIG_SMP
+	update_process_times(user_mode(regs));
+#endif /* CONFIG_SMP */
+
+	/*
+	 * If we have an externally synchronized Linux clock, then update
+	 * RTC clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
+	 * called as close as possible to when a second starts.
+	 */
+	if ((time_status & STA_UNSYNC) == 0 &&
+	    xtime.tv_sec > last_rtc_update + 660) {
+		if (xtime.tv_usec >= 1000000 - ((unsigned) tick) / 2) {
+			if (set_rtc_mmss(xtime.tv_sec + 1) == 0)
+				last_rtc_update = xtime.tv_sec;
+			else
+				last_rtc_update = xtime.tv_sec - 600;
+		} else if (xtime.tv_usec <= ((unsigned) tick) / 2) {
+			if (set_rtc_mmss(xtime.tv_sec) == 0)
+				last_rtc_update = xtime.tv_sec;
+			else
+				last_rtc_update = xtime.tv_sec - 600;
+		}
+        }
+
+	write_unlock(&xtime_lock);
+	irq_exit(cpu, irq);
+
+	if (softirq_pending(cpu))
+		do_softirq();
+}
+
+unsigned long ip27_do_gettimeoffset(void)
+{
+	unsigned long ct_cur1;
+	ct_cur1 = REMOTE_HUB_L(cputonasid(0), PI_RT_COUNT) + CYCLES_PER_JIFFY;
+	return (ct_cur1 - ct_cur[0]) * NSEC_PER_CYCLE / 1000;
+}
+
+/* Includes for ioc3_init().  */
+#include <asm/sn/types.h>
+#include <asm/sn/sn0/addrs.h>
+#include <asm/sn/sn0/hubni.h>
+#include <asm/sn/sn0/hubio.h>
+#include <asm/pci/bridge.h>
+
+static __init unsigned long get_m48t35_time(void)
+{
+        unsigned int year, month, date, hour, min, sec;
+	struct m48t35_rtc *rtc;
+	nasid_t nid;
+
+	nid = get_nasid();
+	rtc = (struct m48t35_rtc *)(KL_CONFIG_CH_CONS_INFO(nid)->memory_base +
+							IOC3_BYTEBUS_DEV0);
+
+	rtc->control |= M48T35_RTC_READ;
+	sec = rtc->sec;
+	min = rtc->min;
+	hour = rtc->hour;
+	date = rtc->date;
+	month = rtc->month;
+	year = rtc->year;
+	rtc->control &= ~M48T35_RTC_READ;
+
+        BCD_TO_BIN(sec);
+        BCD_TO_BIN(min);
+        BCD_TO_BIN(hour);
+        BCD_TO_BIN(date);
+        BCD_TO_BIN(month);
+        BCD_TO_BIN(year);
+
+        year += 1970;
+
+        return mktime(year, month, date, hour, min, sec);
+}
+
+void __init ip27_time_init(void)
+{
+	xtime.tv_sec = get_m48t35_time();
+	xtime.tv_usec = 0;
+
+	do_gettimeoffset = ip27_do_gettimeoffset;
+}
+
+void __init cpu_time_init(void)
+{
+	lboard_t *board;
+	klcpu_t *cpu;
+	int cpuid;
+
+	/* Don't use ARCS.  ARCS is fragile.  Klconfig is simple and sane.  */
+	board = find_lboard(KL_CONFIG_INFO(get_nasid()), KLTYPE_IP27);
+	if (!board)
+		panic("Can't find board info for myself.");
+
+	cpuid = LOCAL_HUB_L(PI_CPU_NUM) ? IP27_CPU0_INDEX : IP27_CPU1_INDEX;
+	cpu = (klcpu_t *) KLCF_COMP(board, cpuid);
+	if (!cpu)
+		panic("No information about myself?");
+
+	printk("CPU %d clock is %dMHz.\n", smp_processor_id(), cpu->cpu_speed);
+
+	set_cp0_status(SRB_TIMOCLK);
+}
+
+void __init hub_rtc_init(cnodeid_t cnode)
+{
+	/*
+	 * We only need to initialize the current node.
+	 * If this is not the current node then it is a cpuless
+	 * node and timeouts will not happen there.
+	 */
+	if (get_compact_nodeid() == cnode) {
+		int cpu = smp_processor_id();
+		LOCAL_HUB_S(PI_RT_EN_A, 1);
+		LOCAL_HUB_S(PI_RT_EN_B, 1);
+		LOCAL_HUB_S(PI_PROF_EN_A, 0);
+		LOCAL_HUB_S(PI_PROF_EN_B, 0);
+		ct_cur[cpu] = CYCLES_PER_JIFFY;
+		LOCAL_HUB_S(PI_RT_COMPARE_A, ct_cur[cpu]);
+		LOCAL_HUB_S(PI_RT_COUNT, 0);
+		LOCAL_HUB_S(PI_RT_PEND_A, 0);
+		LOCAL_HUB_S(PI_RT_COMPARE_B, ct_cur[cpu]);
+		LOCAL_HUB_S(PI_RT_COUNT, 0);
+		LOCAL_HUB_S(PI_RT_PEND_B, 0);
+	}
+}