[PATCH] time: x86_64: split x86_64/kernel/time.c up

In preparation for the x86_64 generic time conversion, this patch splits out
TSC and HPET related code from arch/x86_64/kernel/time.c into respective
hpet.c and tsc.c files.

[akpm@osdl.org: fix printk timestamps]
[akpm@osdl.org: cleanup]
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andi Kleen <ak@muc.de>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/x86_64/kernel/Makefile

@@ -8,7 +8,7 @@ obj-y	:= process.o signal.o entry.o traps.o irq.o \
 		ptrace.o time.o ioport.o ldt.o setup.o i8259.o sys_x86_64.o \
 		x8664_ksyms.o i387.o syscall.o vsyscall.o \
 		setup64.o bootflag.o e820.o reboot.o quirks.o i8237.o \
-		pci-dma.o pci-nommu.o alternative.o
+		pci-dma.o pci-nommu.o alternative.o hpet.o tsc.o
 
 obj-$(CONFIG_STACKTRACE)	+= stacktrace.o
 obj-$(CONFIG_X86_MCE)		+= mce.o therm_throt.o

arch/x86_64/kernel/tsc.c

+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/interrupt.h>
+#include <linux/init.h>
+#include <linux/clocksource.h>
+#include <linux/time.h>
+#include <linux/acpi.h>
+#include <linux/cpufreq.h>
+
+#include <asm/timex.h>
+
+int notsc __initdata = 0;
+
+unsigned int cpu_khz;		/* TSC clocks / usec, not used here */
+EXPORT_SYMBOL(cpu_khz);
+
+/*
+ * do_gettimeoffset() returns microseconds since last timer interrupt was
+ * triggered by hardware. A memory read of HPET is slower than a register read
+ * of TSC, but much more reliable. It's also synchronized to the timer
+ * interrupt. Note that do_gettimeoffset() may return more than hpet_tick, if a
+ * timer interrupt has happened already, but vxtime.trigger wasn't updated yet.
+ * This is not a problem, because jiffies hasn't updated either. They are bound
+ * together by xtime_lock.
+ */
+
+unsigned int do_gettimeoffset_tsc(void)
+{
+	unsigned long t;
+	unsigned long x;
+	t = get_cycles_sync();
+	if (t < vxtime.last_tsc)
+		t = vxtime.last_tsc; /* hack */
+	x = ((t - vxtime.last_tsc) * vxtime.tsc_quot) >> US_SCALE;
+	return x;
+}
+
+static unsigned int cyc2ns_scale __read_mostly;
+
+void set_cyc2ns_scale(unsigned long khz)
+{
+	cyc2ns_scale = (NSEC_PER_MSEC << NS_SCALE) / khz;
+}
+
+unsigned long long cycles_2_ns(unsigned long long cyc)
+{
+	return (cyc * cyc2ns_scale) >> NS_SCALE;
+}
+
+unsigned long long sched_clock(void)
+{
+	unsigned long a = 0;
+
+	/* Could do CPU core sync here. Opteron can execute rdtsc speculatively,
+	 * which means it is not completely exact and may not be monotonous
+	 * between CPUs. But the errors should be too small to matter for
+	 * scheduling purposes.
+	 */
+
+	rdtscll(a);
+	return cycles_2_ns(a);
+}
+
+#ifdef CONFIG_CPU_FREQ
+
+/* Frequency scaling support. Adjust the TSC based timer when the cpu frequency
+ * changes.
+ *
+ * RED-PEN: On SMP we assume all CPUs run with the same frequency.  It's
+ * not that important because current Opteron setups do not support
+ * scaling on SMP anyroads.
+ *
+ * Should fix up last_tsc too. Currently gettimeofday in the
+ * first tick after the change will be slightly wrong.
+ */
+
+#include <linux/workqueue.h>
+
+static unsigned int cpufreq_delayed_issched = 0;
+static unsigned int cpufreq_init = 0;
+static struct work_struct cpufreq_delayed_get_work;
+
+static void handle_cpufreq_delayed_get(struct work_struct *v)
+{
+	unsigned int cpu;
+	for_each_online_cpu(cpu) {
+		cpufreq_get(cpu);
+	}
+	cpufreq_delayed_issched = 0;
+}
+
+/* if we notice lost ticks, schedule a call to cpufreq_get() as it tries
+ * to verify the CPU frequency the timing core thinks the CPU is running
+ * at is still correct.
+ */
+void cpufreq_delayed_get(void)
+{
+	static int warned;
+	if (cpufreq_init && !cpufreq_delayed_issched) {
+		cpufreq_delayed_issched = 1;
+		if (!warned) {
+			warned = 1;
+			printk(KERN_DEBUG "Losing some ticks... "
+				"checking if CPU frequency changed.\n");
+		}
+		schedule_work(&cpufreq_delayed_get_work);
+	}
+}
+
+static unsigned int  ref_freq = 0;
+static unsigned long loops_per_jiffy_ref = 0;
+
+static unsigned long cpu_khz_ref = 0;
+
+static int time_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
+				 void *data)
+{
+	struct cpufreq_freqs *freq = data;
+	unsigned long *lpj, dummy;
+
+	if (cpu_has(&cpu_data[freq->cpu], X86_FEATURE_CONSTANT_TSC))
+		return 0;
+
+	lpj = &dummy;
+	if (!(freq->flags & CPUFREQ_CONST_LOOPS))
+#ifdef CONFIG_SMP
+		lpj = &cpu_data[freq->cpu].loops_per_jiffy;
+#else
+		lpj = &boot_cpu_data.loops_per_jiffy;
+#endif
+
+	if (!ref_freq) {
+		ref_freq = freq->old;
+		loops_per_jiffy_ref = *lpj;
+		cpu_khz_ref = cpu_khz;
+	}
+	if ((val == CPUFREQ_PRECHANGE  && freq->old < freq->new) ||
+		(val == CPUFREQ_POSTCHANGE && freq->old > freq->new) ||
+		(val == CPUFREQ_RESUMECHANGE)) {
+		*lpj =
+		cpufreq_scale(loops_per_jiffy_ref, ref_freq, freq->new);
+
+		cpu_khz = cpufreq_scale(cpu_khz_ref, ref_freq, freq->new);
+		if (!(freq->flags & CPUFREQ_CONST_LOOPS))
+			vxtime.tsc_quot = (USEC_PER_MSEC << US_SCALE) / cpu_khz;
+	}
+
+	set_cyc2ns_scale(cpu_khz_ref);
+
+	return 0;
+}
+
+static struct notifier_block time_cpufreq_notifier_block = {
+	.notifier_call  = time_cpufreq_notifier
+};
+
+static int __init cpufreq_tsc(void)
+{
+	INIT_WORK(&cpufreq_delayed_get_work, handle_cpufreq_delayed_get);
+	if (!cpufreq_register_notifier(&time_cpufreq_notifier_block,
+				       CPUFREQ_TRANSITION_NOTIFIER))
+		cpufreq_init = 1;
+	return 0;
+}
+
+core_initcall(cpufreq_tsc);
+
+#endif
+
+static int tsc_unstable = 0;
+
+void mark_tsc_unstable(void)
+{
+	tsc_unstable = 1;
+}
+EXPORT_SYMBOL_GPL(mark_tsc_unstable);
+
+/*
+ * Make an educated guess if the TSC is trustworthy and synchronized
+ * over all CPUs.
+ */
+__cpuinit int unsynchronized_tsc(void)
+{
+	if (tsc_unstable)
+		return 1;
+
+#ifdef CONFIG_SMP
+	if (apic_is_clustered_box())
+		return 1;
+#endif
+	/* Most intel systems have synchronized TSCs except for
+	   multi node systems */
+ 	if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) {
+#ifdef CONFIG_ACPI
+		/* But TSC doesn't tick in C3 so don't use it there */
+		if (acpi_gbl_FADT.header.length > 0 && acpi_gbl_FADT.C3latency < 1000)
+			return 1;
+#endif
+ 		return 0;
+	}
+
+ 	/* Assume multi socket systems are not synchronized */
+ 	return num_present_cpus() > 1;
+}
+
+int __init notsc_setup(char *s)
+{
+	notsc = 1;
+	return 1;
+}
+
+__setup("notsc", notsc_setup);

include/asm-x86_64/hpet.h

@@ -56,9 +56,15 @@
 extern int is_hpet_enabled(void);
 extern int hpet_rtc_timer_init(void);
 extern int apic_is_clustered_box(void);
+extern int hpet_arch_init(void);
+extern int hpet_timer_stop_set_go(unsigned long tick);
+extern int hpet_reenable(void);
+extern unsigned int hpet_calibrate_tsc(void);
 
 extern int hpet_use_timer;
 extern unsigned long hpet_address;
+extern unsigned long hpet_period;
+extern unsigned long hpet_tick;
 
 #ifdef CONFIG_HPET_EMULATE_RTC
 extern int hpet_mask_rtc_irq_bit(unsigned long bit_mask);

include/asm-x86_64/timex.h

@@ -20,6 +20,17 @@
 extern int read_current_timer(unsigned long *timer_value);
 #define ARCH_HAS_READ_CURRENT_TIMER	1
 
+#define USEC_PER_TICK (USEC_PER_SEC / HZ)
+#define NSEC_PER_TICK (NSEC_PER_SEC / HZ)
+#define FSEC_PER_TICK (FSEC_PER_SEC / HZ)
+
+#define NS_SCALE        10 /* 2^10, carefully chosen */
+#define US_SCALE        32 /* 2^32, arbitralrily chosen */
+
 extern struct vxtime_data vxtime;
 
+extern unsigned int do_gettimeoffset_hpet(void);
+extern unsigned int do_gettimeoffset_tsc(void);
+extern void set_cyc2ns_scale(unsigned long khz);
+extern int notsc;
 #endif

kernel/tsacct.c

@@ -22,8 +22,6 @@
 #include <linux/acct.h>
 #include <linux/jiffies.h>
 
-
-#define USEC_PER_TICK	(USEC_PER_SEC/HZ)
 /*
  * fill in basic accounting fields
  */