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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/i386/kernel/timers
downloadconfigs-2.6.12-rc2.tar.gz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'arch/i386/kernel/timers')
-rw-r--r--arch/i386/kernel/timers/Makefile9
-rw-r--r--arch/i386/kernel/timers/common.c160
-rw-r--r--arch/i386/kernel/timers/timer.c66
-rw-r--r--arch/i386/kernel/timers/timer_cyclone.c259
-rw-r--r--arch/i386/kernel/timers/timer_hpet.c191
-rw-r--r--arch/i386/kernel/timers/timer_none.c39
-rw-r--r--arch/i386/kernel/timers/timer_pit.c206
-rw-r--r--arch/i386/kernel/timers/timer_pm.c258
-rw-r--r--arch/i386/kernel/timers/timer_tsc.c560
9 files changed, 1748 insertions, 0 deletions
diff --git a/arch/i386/kernel/timers/Makefile b/arch/i386/kernel/timers/Makefile
new file mode 100644
index 00000000000..8fa12be658d
--- /dev/null
+++ b/arch/i386/kernel/timers/Makefile
@@ -0,0 +1,9 @@
+#
+# Makefile for x86 timers
+#
+
+obj-y := timer.o timer_none.o timer_tsc.o timer_pit.o common.o
+
+obj-$(CONFIG_X86_CYCLONE_TIMER) += timer_cyclone.o
+obj-$(CONFIG_HPET_TIMER) += timer_hpet.o
+obj-$(CONFIG_X86_PM_TIMER) += timer_pm.o
diff --git a/arch/i386/kernel/timers/common.c b/arch/i386/kernel/timers/common.c
new file mode 100644
index 00000000000..f7f90005e22
--- /dev/null
+++ b/arch/i386/kernel/timers/common.c
@@ -0,0 +1,160 @@
+/*
+ * Common functions used across the timers go here
+ */
+
+#include <linux/init.h>
+#include <linux/timex.h>
+#include <linux/errno.h>
+#include <linux/jiffies.h>
+
+#include <asm/io.h>
+#include <asm/timer.h>
+#include <asm/hpet.h>
+
+#include "mach_timer.h"
+
+/* ------ Calibrate the TSC -------
+ * Return 2^32 * (1 / (TSC clocks per usec)) for do_fast_gettimeoffset().
+ * Too much 64-bit arithmetic here to do this cleanly in C, and for
+ * accuracy's sake we want to keep the overhead on the CTC speaker (channel 2)
+ * output busy loop as low as possible. We avoid reading the CTC registers
+ * directly because of the awkward 8-bit access mechanism of the 82C54
+ * device.
+ */
+
+#define CALIBRATE_TIME (5 * 1000020/HZ)
+
+unsigned long __init calibrate_tsc(void)
+{
+ mach_prepare_counter();
+
+ {
+ unsigned long startlow, starthigh;
+ unsigned long endlow, endhigh;
+ unsigned long count;
+
+ rdtsc(startlow,starthigh);
+ mach_countup(&count);
+ rdtsc(endlow,endhigh);
+
+
+ /* Error: ECTCNEVERSET */
+ if (count <= 1)
+ goto bad_ctc;
+
+ /* 64-bit subtract - gcc just messes up with long longs */
+ __asm__("subl %2,%0\n\t"
+ "sbbl %3,%1"
+ :"=a" (endlow), "=d" (endhigh)
+ :"g" (startlow), "g" (starthigh),
+ "0" (endlow), "1" (endhigh));
+
+ /* Error: ECPUTOOFAST */
+ if (endhigh)
+ goto bad_ctc;
+
+ /* Error: ECPUTOOSLOW */
+ if (endlow <= CALIBRATE_TIME)
+ goto bad_ctc;
+
+ __asm__("divl %2"
+ :"=a" (endlow), "=d" (endhigh)
+ :"r" (endlow), "0" (0), "1" (CALIBRATE_TIME));
+
+ return endlow;
+ }
+
+ /*
+ * The CTC wasn't reliable: we got a hit on the very first read,
+ * or the CPU was so fast/slow that the quotient wouldn't fit in
+ * 32 bits..
+ */
+bad_ctc:
+ return 0;
+}
+
+#ifdef CONFIG_HPET_TIMER
+/* ------ Calibrate the TSC using HPET -------
+ * Return 2^32 * (1 / (TSC clocks per usec)) for getting the CPU freq.
+ * Second output is parameter 1 (when non NULL)
+ * Set 2^32 * (1 / (tsc per HPET clk)) for delay_hpet().
+ * calibrate_tsc() calibrates the processor TSC by comparing
+ * it to the HPET timer of known frequency.
+ * Too much 64-bit arithmetic here to do this cleanly in C
+ */
+#define CALIBRATE_CNT_HPET (5 * hpet_tick)
+#define CALIBRATE_TIME_HPET (5 * KERNEL_TICK_USEC)
+
+unsigned long __init calibrate_tsc_hpet(unsigned long *tsc_hpet_quotient_ptr)
+{
+ unsigned long tsc_startlow, tsc_starthigh;
+ unsigned long tsc_endlow, tsc_endhigh;
+ unsigned long hpet_start, hpet_end;
+ unsigned long result, remain;
+
+ hpet_start = hpet_readl(HPET_COUNTER);
+ rdtsc(tsc_startlow, tsc_starthigh);
+ do {
+ hpet_end = hpet_readl(HPET_COUNTER);
+ } while ((hpet_end - hpet_start) < CALIBRATE_CNT_HPET);
+ rdtsc(tsc_endlow, tsc_endhigh);
+
+ /* 64-bit subtract - gcc just messes up with long longs */
+ __asm__("subl %2,%0\n\t"
+ "sbbl %3,%1"
+ :"=a" (tsc_endlow), "=d" (tsc_endhigh)
+ :"g" (tsc_startlow), "g" (tsc_starthigh),
+ "0" (tsc_endlow), "1" (tsc_endhigh));
+
+ /* Error: ECPUTOOFAST */
+ if (tsc_endhigh)
+ goto bad_calibration;
+
+ /* Error: ECPUTOOSLOW */
+ if (tsc_endlow <= CALIBRATE_TIME_HPET)
+ goto bad_calibration;
+
+ ASM_DIV64_REG(result, remain, tsc_endlow, 0, CALIBRATE_TIME_HPET);
+ if (remain > (tsc_endlow >> 1))
+ result++; /* rounding the result */
+
+ if (tsc_hpet_quotient_ptr) {
+ unsigned long tsc_hpet_quotient;
+
+ ASM_DIV64_REG(tsc_hpet_quotient, remain, tsc_endlow, 0,
+ CALIBRATE_CNT_HPET);
+ if (remain > (tsc_endlow >> 1))
+ tsc_hpet_quotient++; /* rounding the result */
+ *tsc_hpet_quotient_ptr = tsc_hpet_quotient;
+ }
+
+ return result;
+bad_calibration:
+ /*
+ * the CPU was so fast/slow that the quotient wouldn't fit in
+ * 32 bits..
+ */
+ return 0;
+}
+#endif
+
+/* calculate cpu_khz */
+void __init init_cpu_khz(void)
+{
+ if (cpu_has_tsc) {
+ unsigned long tsc_quotient = calibrate_tsc();
+ if (tsc_quotient) {
+ /* report CPU clock rate in Hz.
+ * The formula is (10^6 * 2^32) / (2^32 * 1 / (clocks/us)) =
+ * clock/second. Our precision is about 100 ppm.
+ */
+ { unsigned long eax=0, edx=1000;
+ __asm__("divl %2"
+ :"=a" (cpu_khz), "=d" (edx)
+ :"r" (tsc_quotient),
+ "0" (eax), "1" (edx));
+ printk("Detected %lu.%03lu MHz processor.\n", cpu_khz / 1000, cpu_khz % 1000);
+ }
+ }
+ }
+}
diff --git a/arch/i386/kernel/timers/timer.c b/arch/i386/kernel/timers/timer.c
new file mode 100644
index 00000000000..a3d6a288088
--- /dev/null
+++ b/arch/i386/kernel/timers/timer.c
@@ -0,0 +1,66 @@
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <asm/timer.h>
+
+#ifdef CONFIG_HPET_TIMER
+/*
+ * HPET memory read is slower than tsc reads, but is more dependable as it
+ * always runs at constant frequency and reduces complexity due to
+ * cpufreq. So, we prefer HPET timer to tsc based one. Also, we cannot use
+ * timer_pit when HPET is active. So, we default to timer_tsc.
+ */
+#endif
+/* list of timers, ordered by preference, NULL terminated */
+static struct init_timer_opts* __initdata timers[] = {
+#ifdef CONFIG_X86_CYCLONE_TIMER
+ &timer_cyclone_init,
+#endif
+#ifdef CONFIG_HPET_TIMER
+ &timer_hpet_init,
+#endif
+#ifdef CONFIG_X86_PM_TIMER
+ &timer_pmtmr_init,
+#endif
+ &timer_tsc_init,
+ &timer_pit_init,
+ NULL,
+};
+
+static char clock_override[10] __initdata;
+
+static int __init clock_setup(char* str)
+{
+ if (str)
+ strlcpy(clock_override, str, sizeof(clock_override));
+ return 1;
+}
+__setup("clock=", clock_setup);
+
+
+/* The chosen timesource has been found to be bad.
+ * Fall back to a known good timesource (the PIT)
+ */
+void clock_fallback(void)
+{
+ cur_timer = &timer_pit;
+}
+
+/* iterates through the list of timers, returning the first
+ * one that initializes successfully.
+ */
+struct timer_opts* __init select_timer(void)
+{
+ int i = 0;
+
+ /* find most preferred working timer */
+ while (timers[i]) {
+ if (timers[i]->init)
+ if (timers[i]->init(clock_override) == 0)
+ return timers[i]->opts;
+ ++i;
+ }
+
+ panic("select_timer: Cannot find a suitable timer\n");
+ return NULL;
+}
diff --git a/arch/i386/kernel/timers/timer_cyclone.c b/arch/i386/kernel/timers/timer_cyclone.c
new file mode 100644
index 00000000000..f6f1206a11b
--- /dev/null
+++ b/arch/i386/kernel/timers/timer_cyclone.c
@@ -0,0 +1,259 @@
+/* Cyclone-timer:
+ * This code implements timer_ops for the cyclone counter found
+ * on IBM x440, x360, and other Summit based systems.
+ *
+ * Copyright (C) 2002 IBM, John Stultz (johnstul@us.ibm.com)
+ */
+
+
+#include <linux/spinlock.h>
+#include <linux/init.h>
+#include <linux/timex.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/jiffies.h>
+
+#include <asm/timer.h>
+#include <asm/io.h>
+#include <asm/pgtable.h>
+#include <asm/fixmap.h>
+#include "io_ports.h"
+
+extern spinlock_t i8253_lock;
+
+/* Number of usecs that the last interrupt was delayed */
+static int delay_at_last_interrupt;
+
+#define CYCLONE_CBAR_ADDR 0xFEB00CD0
+#define CYCLONE_PMCC_OFFSET 0x51A0
+#define CYCLONE_MPMC_OFFSET 0x51D0
+#define CYCLONE_MPCS_OFFSET 0x51A8
+#define CYCLONE_TIMER_FREQ 100000000
+#define CYCLONE_TIMER_MASK (((u64)1<<40)-1) /* 40 bit mask */
+int use_cyclone = 0;
+
+static u32* volatile cyclone_timer; /* Cyclone MPMC0 register */
+static u32 last_cyclone_low;
+static u32 last_cyclone_high;
+static unsigned long long monotonic_base;
+static seqlock_t monotonic_lock = SEQLOCK_UNLOCKED;
+
+/* helper macro to atomically read both cyclone counter registers */
+#define read_cyclone_counter(low,high) \
+ do{ \
+ high = cyclone_timer[1]; low = cyclone_timer[0]; \
+ } while (high != cyclone_timer[1]);
+
+
+static void mark_offset_cyclone(void)
+{
+ unsigned long lost, delay;
+ unsigned long delta = last_cyclone_low;
+ int count;
+ unsigned long long this_offset, last_offset;
+
+ write_seqlock(&monotonic_lock);
+ last_offset = ((unsigned long long)last_cyclone_high<<32)|last_cyclone_low;
+
+ spin_lock(&i8253_lock);
+ read_cyclone_counter(last_cyclone_low,last_cyclone_high);
+
+ /* read values for delay_at_last_interrupt */
+ outb_p(0x00, 0x43); /* latch the count ASAP */
+
+ count = inb_p(0x40); /* read the latched count */
+ count |= inb(0x40) << 8;
+
+ /*
+ * VIA686a test code... reset the latch if count > max + 1
+ * from timer_pit.c - cjb
+ */
+ if (count > LATCH) {
+ outb_p(0x34, PIT_MODE);
+ outb_p(LATCH & 0xff, PIT_CH0);
+ outb(LATCH >> 8, PIT_CH0);
+ count = LATCH - 1;
+ }
+ spin_unlock(&i8253_lock);
+
+ /* lost tick compensation */
+ delta = last_cyclone_low - delta;
+ delta /= (CYCLONE_TIMER_FREQ/1000000);
+ delta += delay_at_last_interrupt;
+ lost = delta/(1000000/HZ);
+ delay = delta%(1000000/HZ);
+ if (lost >= 2)
+ jiffies_64 += lost-1;
+
+ /* update the monotonic base value */
+ this_offset = ((unsigned long long)last_cyclone_high<<32)|last_cyclone_low;
+ monotonic_base += (this_offset - last_offset) & CYCLONE_TIMER_MASK;
+ write_sequnlock(&monotonic_lock);
+
+ /* calculate delay_at_last_interrupt */
+ count = ((LATCH-1) - count) * TICK_SIZE;
+ delay_at_last_interrupt = (count + LATCH/2) / LATCH;
+
+
+ /* catch corner case where tick rollover occured
+ * between cyclone and pit reads (as noted when
+ * usec delta is > 90% # of usecs/tick)
+ */
+ if (lost && abs(delay - delay_at_last_interrupt) > (900000/HZ))
+ jiffies_64++;
+}
+
+static unsigned long get_offset_cyclone(void)
+{
+ u32 offset;
+
+ if(!cyclone_timer)
+ return delay_at_last_interrupt;
+
+ /* Read the cyclone timer */
+ offset = cyclone_timer[0];
+
+ /* .. relative to previous jiffy */
+ offset = offset - last_cyclone_low;
+
+ /* convert cyclone ticks to microseconds */
+ /* XXX slow, can we speed this up? */
+ offset = offset/(CYCLONE_TIMER_FREQ/1000000);
+
+ /* our adjusted time offset in microseconds */
+ return delay_at_last_interrupt + offset;
+}
+
+static unsigned long long monotonic_clock_cyclone(void)
+{
+ u32 now_low, now_high;
+ unsigned long long last_offset, this_offset, base;
+ unsigned long long ret;
+ unsigned seq;
+
+ /* atomically read monotonic base & last_offset */
+ do {
+ seq = read_seqbegin(&monotonic_lock);
+ last_offset = ((unsigned long long)last_cyclone_high<<32)|last_cyclone_low;
+ base = monotonic_base;
+ } while (read_seqretry(&monotonic_lock, seq));
+
+
+ /* Read the cyclone counter */
+ read_cyclone_counter(now_low,now_high);
+ this_offset = ((unsigned long long)now_high<<32)|now_low;
+
+ /* convert to nanoseconds */
+ ret = base + ((this_offset - last_offset)&CYCLONE_TIMER_MASK);
+ return ret * (1000000000 / CYCLONE_TIMER_FREQ);
+}
+
+static int __init init_cyclone(char* override)
+{
+ u32* reg;
+ u32 base; /* saved cyclone base address */
+ u32 pageaddr; /* page that contains cyclone_timer register */
+ u32 offset; /* offset from pageaddr to cyclone_timer register */
+ int i;
+
+ /* check clock override */
+ if (override[0] && strncmp(override,"cyclone",7))
+ return -ENODEV;
+
+ /*make sure we're on a summit box*/
+ if(!use_cyclone) return -ENODEV;
+
+ printk(KERN_INFO "Summit chipset: Starting Cyclone Counter.\n");
+
+ /* find base address */
+ pageaddr = (CYCLONE_CBAR_ADDR)&PAGE_MASK;
+ offset = (CYCLONE_CBAR_ADDR)&(~PAGE_MASK);
+ set_fixmap_nocache(FIX_CYCLONE_TIMER, pageaddr);
+ reg = (u32*)(fix_to_virt(FIX_CYCLONE_TIMER) + offset);
+ if(!reg){
+ printk(KERN_ERR "Summit chipset: Could not find valid CBAR register.\n");
+ return -ENODEV;
+ }
+ base = *reg;
+ if(!base){
+ printk(KERN_ERR "Summit chipset: Could not find valid CBAR value.\n");
+ return -ENODEV;
+ }
+
+ /* setup PMCC */
+ pageaddr = (base + CYCLONE_PMCC_OFFSET)&PAGE_MASK;
+ offset = (base + CYCLONE_PMCC_OFFSET)&(~PAGE_MASK);
+ set_fixmap_nocache(FIX_CYCLONE_TIMER, pageaddr);
+ reg = (u32*)(fix_to_virt(FIX_CYCLONE_TIMER) + offset);
+ if(!reg){
+ printk(KERN_ERR "Summit chipset: Could not find valid PMCC register.\n");
+ return -ENODEV;
+ }
+ reg[0] = 0x00000001;
+
+ /* setup MPCS */
+ pageaddr = (base + CYCLONE_MPCS_OFFSET)&PAGE_MASK;
+ offset = (base + CYCLONE_MPCS_OFFSET)&(~PAGE_MASK);
+ set_fixmap_nocache(FIX_CYCLONE_TIMER, pageaddr);
+ reg = (u32*)(fix_to_virt(FIX_CYCLONE_TIMER) + offset);
+ if(!reg){
+ printk(KERN_ERR "Summit chipset: Could not find valid MPCS register.\n");
+ return -ENODEV;
+ }
+ reg[0] = 0x00000001;
+
+ /* map in cyclone_timer */
+ pageaddr = (base + CYCLONE_MPMC_OFFSET)&PAGE_MASK;
+ offset = (base + CYCLONE_MPMC_OFFSET)&(~PAGE_MASK);
+ set_fixmap_nocache(FIX_CYCLONE_TIMER, pageaddr);
+ cyclone_timer = (u32*)(fix_to_virt(FIX_CYCLONE_TIMER) + offset);
+ if(!cyclone_timer){
+ printk(KERN_ERR "Summit chipset: Could not find valid MPMC register.\n");
+ return -ENODEV;
+ }
+
+ /*quick test to make sure its ticking*/
+ for(i=0; i<3; i++){
+ u32 old = cyclone_timer[0];
+ int stall = 100;
+ while(stall--) barrier();
+ if(cyclone_timer[0] == old){
+ printk(KERN_ERR "Summit chipset: Counter not counting! DISABLED\n");
+ cyclone_timer = 0;
+ return -ENODEV;
+ }
+ }
+
+ init_cpu_khz();
+
+ /* Everything looks good! */
+ return 0;
+}
+
+
+static void delay_cyclone(unsigned long loops)
+{
+ unsigned long bclock, now;
+ if(!cyclone_timer)
+ return;
+ bclock = cyclone_timer[0];
+ do {
+ rep_nop();
+ now = cyclone_timer[0];
+ } while ((now-bclock) < loops);
+}
+/************************************************************/
+
+/* cyclone timer_opts struct */
+static struct timer_opts timer_cyclone = {
+ .name = "cyclone",
+ .mark_offset = mark_offset_cyclone,
+ .get_offset = get_offset_cyclone,
+ .monotonic_clock = monotonic_clock_cyclone,
+ .delay = delay_cyclone,
+};
+
+struct init_timer_opts __initdata timer_cyclone_init = {
+ .init = init_cyclone,
+ .opts = &timer_cyclone,
+};
diff --git a/arch/i386/kernel/timers/timer_hpet.c b/arch/i386/kernel/timers/timer_hpet.c
new file mode 100644
index 00000000000..713134e7184
--- /dev/null
+++ b/arch/i386/kernel/timers/timer_hpet.c
@@ -0,0 +1,191 @@
+/*
+ * This code largely moved from arch/i386/kernel/time.c.
+ * See comments there for proper credits.
+ */
+
+#include <linux/spinlock.h>
+#include <linux/init.h>
+#include <linux/timex.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/jiffies.h>
+
+#include <asm/timer.h>
+#include <asm/io.h>
+#include <asm/processor.h>
+
+#include "io_ports.h"
+#include "mach_timer.h"
+#include <asm/hpet.h>
+
+static unsigned long hpet_usec_quotient; /* convert hpet clks to usec */
+static unsigned long tsc_hpet_quotient; /* convert tsc to hpet clks */
+static unsigned long hpet_last; /* hpet counter value at last tick*/
+static unsigned long last_tsc_low; /* lsb 32 bits of Time Stamp Counter */
+static unsigned long last_tsc_high; /* msb 32 bits of Time Stamp Counter */
+static unsigned long long monotonic_base;
+static seqlock_t monotonic_lock = SEQLOCK_UNLOCKED;
+
+/* convert from cycles(64bits) => nanoseconds (64bits)
+ * basic equation:
+ * ns = cycles / (freq / ns_per_sec)
+ * ns = cycles * (ns_per_sec / freq)
+ * ns = cycles * (10^9 / (cpu_mhz * 10^6))
+ * ns = cycles * (10^3 / cpu_mhz)
+ *
+ * Then we use scaling math (suggested by george@mvista.com) to get:
+ * ns = cycles * (10^3 * SC / cpu_mhz) / SC
+ * ns = cycles * cyc2ns_scale / SC
+ *
+ * And since SC is a constant power of two, we can convert the div
+ * into a shift.
+ * -johnstul@us.ibm.com "math is hard, lets go shopping!"
+ */
+static unsigned long cyc2ns_scale;
+#define CYC2NS_SCALE_FACTOR 10 /* 2^10, carefully chosen */
+
+static inline void set_cyc2ns_scale(unsigned long cpu_mhz)
+{
+ cyc2ns_scale = (1000 << CYC2NS_SCALE_FACTOR)/cpu_mhz;
+}
+
+static inline unsigned long long cycles_2_ns(unsigned long long cyc)
+{
+ return (cyc * cyc2ns_scale) >> CYC2NS_SCALE_FACTOR;
+}
+
+static unsigned long long monotonic_clock_hpet(void)
+{
+ unsigned long long last_offset, this_offset, base;
+ unsigned seq;
+
+ /* atomically read monotonic base & last_offset */
+ do {
+ seq = read_seqbegin(&monotonic_lock);
+ last_offset = ((unsigned long long)last_tsc_high<<32)|last_tsc_low;
+ base = monotonic_base;
+ } while (read_seqretry(&monotonic_lock, seq));
+
+ /* Read the Time Stamp Counter */
+ rdtscll(this_offset);
+
+ /* return the value in ns */
+ return base + cycles_2_ns(this_offset - last_offset);
+}
+
+static unsigned long get_offset_hpet(void)
+{
+ register unsigned long eax, edx;
+
+ eax = hpet_readl(HPET_COUNTER);
+ eax -= hpet_last; /* hpet delta */
+
+ /*
+ * Time offset = (hpet delta) * ( usecs per HPET clock )
+ * = (hpet delta) * ( usecs per tick / HPET clocks per tick)
+ * = (hpet delta) * ( hpet_usec_quotient ) / (2^32)
+ *
+ * Where,
+ * hpet_usec_quotient = (2^32 * usecs per tick)/HPET clocks per tick
+ *
+ * Using a mull instead of a divl saves some cycles in critical path.
+ */
+ ASM_MUL64_REG(eax, edx, hpet_usec_quotient, eax);
+
+ /* our adjusted time offset in microseconds */
+ return edx;
+}
+
+static void mark_offset_hpet(void)
+{
+ unsigned long long this_offset, last_offset;
+ unsigned long offset;
+
+ write_seqlock(&monotonic_lock);
+ last_offset = ((unsigned long long)last_tsc_high<<32)|last_tsc_low;
+ rdtsc(last_tsc_low, last_tsc_high);
+
+ offset = hpet_readl(HPET_T0_CMP) - hpet_tick;
+ if (unlikely(((offset - hpet_last) > hpet_tick) && (hpet_last != 0))) {
+ int lost_ticks = (offset - hpet_last) / hpet_tick;
+ jiffies_64 += lost_ticks;
+ }
+ hpet_last = offset;
+
+ /* update the monotonic base value */
+ this_offset = ((unsigned long long)last_tsc_high<<32)|last_tsc_low;
+ monotonic_base += cycles_2_ns(this_offset - last_offset);
+ write_sequnlock(&monotonic_lock);
+}
+
+static void delay_hpet(unsigned long loops)
+{
+ unsigned long hpet_start, hpet_end;
+ unsigned long eax;
+
+ /* loops is the number of cpu cycles. Convert it to hpet clocks */
+ ASM_MUL64_REG(eax, loops, tsc_hpet_quotient, loops);
+
+ hpet_start = hpet_readl(HPET_COUNTER);
+ do {
+ rep_nop();
+ hpet_end = hpet_readl(HPET_COUNTER);
+ } while ((hpet_end - hpet_start) < (loops));
+}
+
+static int __init init_hpet(char* override)
+{
+ unsigned long result, remain;
+
+ /* check clock override */
+ if (override[0] && strncmp(override,"hpet",4))
+ return -ENODEV;
+
+ if (!is_hpet_enabled())
+ return -ENODEV;
+
+ printk("Using HPET for gettimeofday\n");
+ if (cpu_has_tsc) {
+ unsigned long tsc_quotient = calibrate_tsc_hpet(&tsc_hpet_quotient);
+ if (tsc_quotient) {
+ /* report CPU clock rate in Hz.
+ * The formula is (10^6 * 2^32) / (2^32 * 1 / (clocks/us)) =
+ * clock/second. Our precision is about 100 ppm.
+ */
+ { unsigned long eax=0, edx=1000;
+ ASM_DIV64_REG(cpu_khz, edx, tsc_quotient,
+ eax, edx);
+ printk("Detected %lu.%03lu MHz processor.\n",
+ cpu_khz / 1000, cpu_khz % 1000);
+ }
+ set_cyc2ns_scale(cpu_khz/1000);
+ }
+ }
+
+ /*
+ * Math to calculate hpet to usec multiplier
+ * Look for the comments at get_offset_hpet()
+ */
+ ASM_DIV64_REG(result, remain, hpet_tick, 0, KERNEL_TICK_USEC);
+ if (remain > (hpet_tick >> 1))
+ result++; /* rounding the result */
+ hpet_usec_quotient = result;
+
+ return 0;
+}
+
+/************************************************************/
+
+/* tsc timer_opts struct */
+static struct timer_opts timer_hpet = {
+ .name = "hpet",
+ .mark_offset = mark_offset_hpet,
+ .get_offset = get_offset_hpet,
+ .monotonic_clock = monotonic_clock_hpet,
+ .delay = delay_hpet,
+};
+
+struct init_timer_opts __initdata timer_hpet_init = {
+ .init = init_hpet,
+ .opts = &timer_hpet,
+};
diff --git a/arch/i386/kernel/timers/timer_none.c b/arch/i386/kernel/timers/timer_none.c
new file mode 100644
index 00000000000..4ea2f414dbb
--- /dev/null
+++ b/arch/i386/kernel/timers/timer_none.c
@@ -0,0 +1,39 @@
+#include <linux/init.h>
+#include <asm/timer.h>
+
+static void mark_offset_none(void)
+{
+ /* nothing needed */
+}
+
+static unsigned long get_offset_none(void)
+{
+ return 0;
+}
+
+static unsigned long long monotonic_clock_none(void)
+{
+ return 0;
+}
+
+static void delay_none(unsigned long loops)
+{
+ int d0;
+ __asm__ __volatile__(
+ "\tjmp 1f\n"
+ ".align 16\n"
+ "1:\tjmp 2f\n"
+ ".align 16\n"
+ "2:\tdecl %0\n\tjns 2b"
+ :"=&a" (d0)
+ :"0" (loops));
+}
+
+/* none timer_opts struct */
+struct timer_opts timer_none = {
+ .name = "none",
+ .mark_offset = mark_offset_none,
+ .get_offset = get_offset_none,
+ .monotonic_clock = monotonic_clock_none,
+ .delay = delay_none,
+};
diff --git a/arch/i386/kernel/timers/timer_pit.c b/arch/i386/kernel/timers/timer_pit.c
new file mode 100644
index 00000000000..967d5453cd0
--- /dev/null
+++ b/arch/i386/kernel/timers/timer_pit.c
@@ -0,0 +1,206 @@
+/*
+ * This code largely moved from arch/i386/kernel/time.c.
+ * See comments there for proper credits.
+ */
+
+#include <linux/spinlock.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/irq.h>
+#include <linux/sysdev.h>
+#include <linux/timex.h>
+#include <asm/delay.h>
+#include <asm/mpspec.h>
+#include <asm/timer.h>
+#include <asm/smp.h>
+#include <asm/io.h>
+#include <asm/arch_hooks.h>
+
+extern spinlock_t i8259A_lock;
+extern spinlock_t i8253_lock;
+#include "do_timer.h"
+#include "io_ports.h"
+
+static int count_p; /* counter in get_offset_pit() */
+
+static int __init init_pit(char* override)
+{
+ /* check clock override */
+ if (override[0] && strncmp(override,"pit",3))
+ printk(KERN_ERR "Warning: clock= override failed. Defaulting to PIT\n");
+
+ count_p = LATCH;
+ return 0;
+}
+
+static void mark_offset_pit(void)
+{
+ /* nothing needed */
+}
+
+static unsigned long long monotonic_clock_pit(void)
+{
+ return 0;
+}
+
+static void delay_pit(unsigned long loops)
+{
+ int d0;
+ __asm__ __volatile__(
+ "\tjmp 1f\n"
+ ".align 16\n"
+ "1:\tjmp 2f\n"
+ ".align 16\n"
+ "2:\tdecl %0\n\tjns 2b"
+ :"=&a" (d0)
+ :"0" (loops));
+}
+
+
+/* This function must be called with xtime_lock held.
+ * It was inspired by Steve McCanne's microtime-i386 for BSD. -- jrs
+ *
+ * However, the pc-audio speaker driver changes the divisor so that
+ * it gets interrupted rather more often - it loads 64 into the
+ * counter rather than 11932! This has an adverse impact on
+ * do_gettimeoffset() -- it stops working! What is also not
+ * good is that the interval that our timer function gets called
+ * is no longer 10.0002 ms, but 9.9767 ms. To get around this
+ * would require using a different timing source. Maybe someone
+ * could use the RTC - I know that this can interrupt at frequencies
+ * ranging from 8192Hz to 2Hz. If I had the energy, I'd somehow fix
+ * it so that at startup, the timer code in sched.c would select
+ * using either the RTC or the 8253 timer. The decision would be
+ * based on whether there was any other device around that needed
+ * to trample on the 8253. I'd set up the RTC to interrupt at 1024 Hz,
+ * and then do some jiggery to have a version of do_timer that
+ * advanced the clock by 1/1024 s. Every time that reached over 1/100
+ * of a second, then do all the old code. If the time was kept correct
+ * then do_gettimeoffset could just return 0 - there is no low order
+ * divider that can be accessed.
+ *
+ * Ideally, you would be able to use the RTC for the speaker driver,
+ * but it appears that the speaker driver really needs interrupt more
+ * often than every 120 us or so.
+ *
+ * Anyway, this needs more thought.... pjsg (1993-08-28)
+ *
+ * If you are really that interested, you should be reading
+ * comp.protocols.time.ntp!
+ */
+
+static unsigned long get_offset_pit(void)
+{
+ int count;
+ unsigned long flags;
+ static unsigned long jiffies_p = 0;
+
+ /*
+ * cache volatile jiffies temporarily; we have xtime_lock.
+ */
+ unsigned long jiffies_t;
+
+ spin_lock_irqsave(&i8253_lock, flags);
+ /* timer count may underflow right here */
+ outb_p(0x00, PIT_MODE); /* latch the count ASAP */
+
+ count = inb_p(PIT_CH0); /* read the latched count */
+
+ /*
+ * We do this guaranteed double memory access instead of a _p
+ * postfix in the previous port access. Wheee, hackady hack
+ */
+ jiffies_t = jiffies;
+
+ count |= inb_p(PIT_CH0) << 8;
+
+ /* VIA686a test code... reset the latch if count > max + 1 */
+ if (count > LATCH) {
+ outb_p(0x34, PIT_MODE);
+ outb_p(LATCH & 0xff, PIT_CH0);
+ outb(LATCH >> 8, PIT_CH0);
+ count = LATCH - 1;
+ }
+
+ /*
+ * avoiding timer inconsistencies (they are rare, but they happen)...
+ * there are two kinds of problems that must be avoided here:
+ * 1. the timer counter underflows
+ * 2. hardware problem with the timer, not giving us continuous time,
+ * the counter does small "jumps" upwards on some Pentium systems,
+ * (see c't 95/10 page 335 for Neptun bug.)
+ */
+
+ if( jiffies_t == jiffies_p ) {
+ if( count > count_p ) {
+ /* the nutcase */
+ count = do_timer_overflow(count);
+ }
+ } else
+ jiffies_p = jiffies_t;
+
+ count_p = count;
+
+ spin_unlock_irqrestore(&i8253_lock, flags);
+
+ count = ((LATCH-1) - count) * TICK_SIZE;
+ count = (count + LATCH/2) / LATCH;
+
+ return count;
+}
+
+
+/* tsc timer_opts struct */
+struct timer_opts timer_pit = {
+ .name = "pit",
+ .mark_offset = mark_offset_pit,
+ .get_offset = get_offset_pit,
+ .monotonic_clock = monotonic_clock_pit,
+ .delay = delay_pit,
+};
+
+struct init_timer_opts __initdata timer_pit_init = {
+ .init = init_pit,
+ .opts = &timer_pit,
+};
+
+void setup_pit_timer(void)
+{
+ extern spinlock_t i8253_lock;
+ unsigned long flags;
+
+ spin_lock_irqsave(&i8253_lock, flags);
+ outb_p(0x34,PIT_MODE); /* binary, mode 2, LSB/MSB, ch 0 */
+ udelay(10);
+ outb_p(LATCH & 0xff , PIT_CH0); /* LSB */
+ udelay(10);
+ outb(LATCH >> 8 , PIT_CH0); /* MSB */
+ spin_unlock_irqrestore(&i8253_lock, flags);
+}
+
+static int timer_resume(struct sys_device *dev)
+{
+ setup_pit_timer();
+ return 0;
+}
+
+static struct sysdev_class timer_sysclass = {
+ set_kset_name("timer_pit"),
+ .resume = timer_resume,
+};
+
+static struct sys_device device_timer = {
+ .id = 0,
+ .cls = &timer_sysclass,
+};
+
+static int __init init_timer_sysfs(void)
+{
+ int error = sysdev_class_register(&timer_sysclass);
+ if (!error)
+ error = sysdev_register(&device_timer);
+ return error;
+}
+
+device_initcall(init_timer_sysfs);
+
diff --git a/arch/i386/kernel/timers/timer_pm.c b/arch/i386/kernel/timers/timer_pm.c
new file mode 100644
index 00000000000..d77f22030fe
--- /dev/null
+++ b/arch/i386/kernel/timers/timer_pm.c
@@ -0,0 +1,258 @@
+/*
+ * (C) Dominik Brodowski <linux@brodo.de> 2003
+ *
+ * Driver to use the Power Management Timer (PMTMR) available in some
+ * southbridges as primary timing source for the Linux kernel.
+ *
+ * Based on parts of linux/drivers/acpi/hardware/hwtimer.c, timer_pit.c,
+ * timer_hpet.c, and on Arjan van de Ven's implementation for 2.4.
+ *
+ * This file is licensed under the GPL v2.
+ */
+
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/init.h>
+#include <asm/types.h>
+#include <asm/timer.h>
+#include <asm/smp.h>
+#include <asm/io.h>
+#include <asm/arch_hooks.h>
+
+#include <linux/timex.h>
+#include "mach_timer.h"
+
+/* Number of PMTMR ticks expected during calibration run */
+#define PMTMR_TICKS_PER_SEC 3579545
+#define PMTMR_EXPECTED_RATE \
+ ((CALIBRATE_LATCH * (PMTMR_TICKS_PER_SEC >> 10)) / (CLOCK_TICK_RATE>>10))
+
+
+/* The I/O port the PMTMR resides at.
+ * The location is detected during setup_arch(),
+ * in arch/i386/acpi/boot.c */
+u32 pmtmr_ioport = 0;
+
+
+/* value of the Power timer at last timer interrupt */
+static u32 offset_tick;
+static u32 offset_delay;
+
+static unsigned long long monotonic_base;
+static seqlock_t monotonic_lock = SEQLOCK_UNLOCKED;
+
+#define ACPI_PM_MASK 0xFFFFFF /* limit it to 24 bits */
+
+/*helper function to safely read acpi pm timesource*/
+static inline u32 read_pmtmr(void)
+{
+ u32 v1=0,v2=0,v3=0;
+ /* It has been reported that because of various broken
+ * chipsets (ICH4, PIIX4 and PIIX4E) where the ACPI PM time
+ * source is not latched, so you must read it multiple
+ * times to insure a safe value is read.
+ */
+ do {
+ v1 = inl(pmtmr_ioport);
+ v2 = inl(pmtmr_ioport);
+ v3 = inl(pmtmr_ioport);
+ } while ((v1 > v2 && v1 < v3) || (v2 > v3 && v2 < v1)
+ || (v3 > v1 && v3 < v2));
+
+ /* mask the output to 24 bits */
+ return v2 & ACPI_PM_MASK;
+}
+
+
+/*
+ * Some boards have the PMTMR running way too fast. We check
+ * the PMTMR rate against PIT channel 2 to catch these cases.
+ */
+static int verify_pmtmr_rate(void)
+{
+ u32 value1, value2;
+ unsigned long count, delta;
+
+ mach_prepare_counter();
+ value1 = read_pmtmr();
+ mach_countup(&count);
+ value2 = read_pmtmr();
+ delta = (value2 - value1) & ACPI_PM_MASK;
+
+ /* Check that the PMTMR delta is within 5% of what we expect */
+ if (delta < (PMTMR_EXPECTED_RATE * 19) / 20 ||
+ delta > (PMTMR_EXPECTED_RATE * 21) / 20) {
+ printk(KERN_INFO "PM-Timer running at invalid rate: %lu%% of normal - aborting.\n", 100UL * delta / PMTMR_EXPECTED_RATE);
+ return -1;
+ }
+
+ return 0;
+}
+
+
+static int init_pmtmr(char* override)
+{
+ u32 value1, value2;
+ unsigned int i;
+
+ if (override[0] && strncmp(override,"pmtmr",5))
+ return -ENODEV;
+
+ if (!pmtmr_ioport)
+ return -ENODEV;
+
+ /* we use the TSC for delay_pmtmr, so make sure it exists */
+ if (!cpu_has_tsc)
+ return -ENODEV;
+
+ /* "verify" this timing source */
+ value1 = read_pmtmr();
+ for (i = 0; i < 10000; i++) {
+ value2 = read_pmtmr();
+ if (value2 == value1)
+ continue;
+ if (value2 > value1)
+ goto pm_good;
+ if ((value2 < value1) && ((value2) < 0xFFF))
+ goto pm_good;
+ printk(KERN_INFO "PM-Timer had inconsistent results: 0x%#x, 0x%#x - aborting.\n", value1, value2);
+ return -EINVAL;
+ }
+ printk(KERN_INFO "PM-Timer had no reasonable result: 0x%#x - aborting.\n", value1);
+ return -ENODEV;
+
+pm_good:
+ if (verify_pmtmr_rate() != 0)
+ return -ENODEV;
+
+ init_cpu_khz();
+ return 0;
+}
+
+static inline u32 cyc2us(u32 cycles)
+{
+ /* The Power Management Timer ticks at 3.579545 ticks per microsecond.
+ * 1 / PM_TIMER_FREQUENCY == 0.27936511 =~ 286/1024 [error: 0.024%]
+ *
+ * Even with HZ = 100, delta is at maximum 35796 ticks, so it can
+ * easily be multiplied with 286 (=0x11E) without having to fear
+ * u32 overflows.
+ */
+ cycles *= 286;
+ return (cycles >> 10);
+}
+
+/*
+ * this gets called during each timer interrupt
+ * - Called while holding the writer xtime_lock
+ */
+static void mark_offset_pmtmr(void)
+{
+ u32 lost, delta, last_offset;
+ static int first_run = 1;
+ last_offset = offset_tick;
+
+ write_seqlock(&monotonic_lock);
+
+ offset_tick = read_pmtmr();
+
+ /* calculate tick interval */
+ delta = (offset_tick - last_offset) & ACPI_PM_MASK;
+
+ /* convert to usecs */
+ delta = cyc2us(delta);
+
+ /* update the monotonic base value */
+ monotonic_base += delta * NSEC_PER_USEC;
+ write_sequnlock(&monotonic_lock);
+
+ /* convert to ticks */
+ delta += offset_delay;
+ lost = delta / (USEC_PER_SEC / HZ);
+ offset_delay = delta % (USEC_PER_SEC / HZ);
+
+
+ /* compensate for lost ticks */
+ if (lost >= 2)
+ jiffies_64 += lost - 1;
+
+ /* don't calculate delay for first run,
+ or if we've got less then a tick */
+ if (first_run || (lost < 1)) {
+ first_run = 0;
+ offset_delay = 0;
+ }
+}
+
+
+static unsigned long long monotonic_clock_pmtmr(void)
+{
+ u32 last_offset, this_offset;
+ unsigned long long base, ret;
+ unsigned seq;
+
+
+ /* atomically read monotonic base & last_offset */
+ do {
+ seq = read_seqbegin(&monotonic_lock);
+ last_offset = offset_tick;
+ base = monotonic_base;
+ } while (read_seqretry(&monotonic_lock, seq));
+
+ /* Read the pmtmr */
+ this_offset = read_pmtmr();
+
+ /* convert to nanoseconds */
+ ret = (this_offset - last_offset) & ACPI_PM_MASK;
+ ret = base + (cyc2us(ret) * NSEC_PER_USEC);
+ return ret;
+}
+
+static void delay_pmtmr(unsigned long loops)
+{
+ unsigned long bclock, now;
+
+ rdtscl(bclock);
+ do
+ {
+ rep_nop();
+ rdtscl(now);
+ } while ((now-bclock) < loops);
+}
+
+
+/*
+ * get the offset (in microseconds) from the last call to mark_offset()
+ * - Called holding a reader xtime_lock
+ */
+static unsigned long get_offset_pmtmr(void)
+{
+ u32 now, offset, delta = 0;
+
+ offset = offset_tick;
+ now = read_pmtmr();
+ delta = (now - offset)&ACPI_PM_MASK;
+
+ return (unsigned long) offset_delay + cyc2us(delta);
+}
+
+
+/* acpi timer_opts struct */
+static struct timer_opts timer_pmtmr = {
+ .name = "pmtmr",
+ .mark_offset = mark_offset_pmtmr,
+ .get_offset = get_offset_pmtmr,
+ .monotonic_clock = monotonic_clock_pmtmr,
+ .delay = delay_pmtmr,
+};
+
+struct init_timer_opts __initdata timer_pmtmr_init = {
+ .init = init_pmtmr,
+ .opts = &timer_pmtmr,
+};
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Dominik Brodowski <linux@brodo.de>");
+MODULE_DESCRIPTION("Power Management Timer (PMTMR) as primary timing source for x86");
diff --git a/arch/i386/kernel/timers/timer_tsc.c b/arch/i386/kernel/timers/timer_tsc.c
new file mode 100644
index 00000000000..a685994e5c8
--- /dev/null
+++ b/arch/i386/kernel/timers/timer_tsc.c
@@ -0,0 +1,560 @@
+/*
+ * This code largely moved from arch/i386/kernel/time.c.
+ * See comments there for proper credits.
+ *
+ * 2004-06-25 Jesper Juhl
+ * moved mark_offset_tsc below cpufreq_delayed_get to avoid gcc 3.4
+ * failing to inline.
+ */
+
+#include <linux/spinlock.h>
+#include <linux/init.h>
+#include <linux/timex.h>
+#include <linux/errno.h>
+#include <linux/cpufreq.h>
+#include <linux/string.h>
+#include <linux/jiffies.h>
+
+#include <asm/timer.h>
+#include <asm/io.h>
+/* processor.h for distable_tsc flag */
+#include <asm/processor.h>
+
+#include "io_ports.h"
+#include "mach_timer.h"
+
+#include <asm/hpet.h>
+
+#ifdef CONFIG_HPET_TIMER
+static unsigned long hpet_usec_quotient;
+static unsigned long hpet_last;
+static struct timer_opts timer_tsc;
+#endif
+
+static inline void cpufreq_delayed_get(void);
+
+int tsc_disable __initdata = 0;
+
+extern spinlock_t i8253_lock;
+
+static int use_tsc;
+/* Number of usecs that the last interrupt was delayed */
+static int delay_at_last_interrupt;
+
+static unsigned long last_tsc_low; /* lsb 32 bits of Time Stamp Counter */
+static unsigned long last_tsc_high; /* msb 32 bits of Time Stamp Counter */
+static unsigned long long monotonic_base;
+static seqlock_t monotonic_lock = SEQLOCK_UNLOCKED;
+
+/* convert from cycles(64bits) => nanoseconds (64bits)
+ * basic equation:
+ * ns = cycles / (freq / ns_per_sec)
+ * ns = cycles * (ns_per_sec / freq)
+ * ns = cycles * (10^9 / (cpu_mhz * 10^6))
+ * ns = cycles * (10^3 / cpu_mhz)
+ *
+ * Then we use scaling math (suggested by george@mvista.com) to get:
+ * ns = cycles * (10^3 * SC / cpu_mhz) / SC
+ * ns = cycles * cyc2ns_scale / SC
+ *
+ * And since SC is a constant power of two, we can convert the div
+ * into a shift.
+ * -johnstul@us.ibm.com "math is hard, lets go shopping!"
+ */
+static unsigned long cyc2ns_scale;
+#define CYC2NS_SCALE_FACTOR 10 /* 2^10, carefully chosen */
+
+static inline void set_cyc2ns_scale(unsigned long cpu_mhz)
+{
+ cyc2ns_scale = (1000 << CYC2NS_SCALE_FACTOR)/cpu_mhz;
+}
+
+static inline unsigned long long cycles_2_ns(unsigned long long cyc)
+{
+ return (cyc * cyc2ns_scale) >> CYC2NS_SCALE_FACTOR;
+}
+
+static int count2; /* counter for mark_offset_tsc() */
+
+/* Cached *multiplier* to convert TSC counts to microseconds.
+ * (see the equation below).
+ * Equal to 2^32 * (1 / (clocks per usec) ).
+ * Initialized in time_init.
+ */
+static unsigned long fast_gettimeoffset_quotient;
+
+static unsigned long get_offset_tsc(void)
+{
+ register unsigned long eax, edx;
+
+ /* Read the Time Stamp Counter */
+
+ rdtsc(eax,edx);
+
+ /* .. relative to previous jiffy (32 bits is enough) */
+ eax -= last_tsc_low; /* tsc_low delta */
+
+ /*
+ * Time offset = (tsc_low delta) * fast_gettimeoffset_quotient
+ * = (tsc_low delta) * (usecs_per_clock)
+ * = (tsc_low delta) * (usecs_per_jiffy / clocks_per_jiffy)
+ *
+ * Using a mull instead of a divl saves up to 31 clock cycles
+ * in the critical path.
+ */
+
+ __asm__("mull %2"
+ :"=a" (eax), "=d" (edx)
+ :"rm" (fast_gettimeoffset_quotient),
+ "0" (eax));
+
+ /* our adjusted time offset in microseconds */
+ return delay_at_last_interrupt + edx;
+}
+
+static unsigned long long monotonic_clock_tsc(void)
+{
+ unsigned long long last_offset, this_offset, base;
+ unsigned seq;
+
+ /* atomically read monotonic base & last_offset */
+ do {
+ seq = read_seqbegin(&monotonic_lock);
+ last_offset = ((unsigned long long)last_tsc_high<<32)|last_tsc_low;
+ base = monotonic_base;
+ } while (read_seqretry(&monotonic_lock, seq));
+
+ /* Read the Time Stamp Counter */
+ rdtscll(this_offset);
+
+ /* return the value in ns */
+ return base + cycles_2_ns(this_offset - last_offset);
+}
+
+/*
+ * Scheduler clock - returns current time in nanosec units.
+ */
+unsigned long long sched_clock(void)
+{
+ unsigned long long this_offset;
+
+ /*
+ * In the NUMA case we dont use the TSC as they are not
+ * synchronized across all CPUs.
+ */
+#ifndef CONFIG_NUMA
+ if (!use_tsc)
+#endif
+ /* no locking but a rare wrong value is not a big deal */
+ return jiffies_64 * (1000000000 / HZ);
+
+ /* Read the Time Stamp Counter */
+ rdtscll(this_offset);
+
+ /* return the value in ns */
+ return cycles_2_ns(this_offset);
+}
+
+static void delay_tsc(unsigned long loops)
+{
+ unsigned long bclock, now;
+
+ rdtscl(bclock);
+ do
+ {
+ rep_nop();
+ rdtscl(now);
+ } while ((now-bclock) < loops);
+}
+
+#ifdef CONFIG_HPET_TIMER
+static void mark_offset_tsc_hpet(void)
+{
+ unsigned long long this_offset, last_offset;
+ unsigned long offset, temp, hpet_current;
+
+ write_seqlock(&monotonic_lock);
+ last_offset = ((unsigned long long)last_tsc_high<<32)|last_tsc_low;
+ /*
+ * It is important that these two operations happen almost at
+ * the same time. We do the RDTSC stuff first, since it's
+ * faster. To avoid any inconsistencies, we need interrupts
+ * disabled locally.
+ */
+ /*
+ * Interrupts are just disabled locally since the timer irq
+ * has the SA_INTERRUPT flag set. -arca
+ */
+ /* read Pentium cycle counter */
+
+ hpet_current = hpet_readl(HPET_COUNTER);
+ rdtsc(last_tsc_low, last_tsc_high);
+
+ /* lost tick compensation */
+ offset = hpet_readl(HPET_T0_CMP) - hpet_tick;
+ if (unlikely(((offset - hpet_last) > hpet_tick) && (hpet_last != 0))) {
+ int lost_ticks = (offset - hpet_last) / hpet_tick;
+ jiffies_64 += lost_ticks;
+ }
+ hpet_last = hpet_current;
+
+ /* update the monotonic base value */
+ this_offset = ((unsigned long long)last_tsc_high<<32)|last_tsc_low;
+ monotonic_base += cycles_2_ns(this_offset - last_offset);
+ write_sequnlock(&monotonic_lock);
+
+ /* calculate delay_at_last_interrupt */
+ /*
+ * Time offset = (hpet delta) * ( usecs per HPET clock )
+ * = (hpet delta) * ( usecs per tick / HPET clocks per tick)
+ * = (hpet delta) * ( hpet_usec_quotient ) / (2^32)
+ * Where,
+ * hpet_usec_quotient = (2^32 * usecs per tick)/HPET clocks per tick
+ */
+ delay_at_last_interrupt = hpet_current - offset;
+ ASM_MUL64_REG(temp, delay_at_last_interrupt,
+ hpet_usec_quotient, delay_at_last_interrupt);
+}
+#endif
+
+
+#ifdef CONFIG_CPU_FREQ
+#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(void *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.
+ */
+static inline void cpufreq_delayed_get(void)
+{
+ if (cpufreq_init && !cpufreq_delayed_issched) {
+ cpufreq_delayed_issched = 1;
+ printk(KERN_DEBUG "Losing some ticks... checking if CPU frequency changed.\n");
+ schedule_work(&cpufreq_delayed_get_work);
+ }
+}
+
+/* If the CPU frequency is scaled, TSC-based delays will need a different
+ * loops_per_jiffy value to function properly.
+ */
+
+static unsigned int ref_freq = 0;
+static unsigned long loops_per_jiffy_ref = 0;
+
+#ifndef CONFIG_SMP
+static unsigned long fast_gettimeoffset_ref = 0;
+static unsigned long cpu_khz_ref = 0;
+#endif
+
+static int
+time_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
+ void *data)
+{
+ struct cpufreq_freqs *freq = data;
+
+ if (val != CPUFREQ_RESUMECHANGE)
+ write_seqlock_irq(&xtime_lock);
+ if (!ref_freq) {
+ ref_freq = freq->old;
+ loops_per_jiffy_ref = cpu_data[freq->cpu].loops_per_jiffy;
+#ifndef CONFIG_SMP
+ fast_gettimeoffset_ref = fast_gettimeoffset_quotient;
+ cpu_khz_ref = cpu_khz;
+#endif
+ }
+
+ if ((val == CPUFREQ_PRECHANGE && freq->old < freq->new) ||
+ (val == CPUFREQ_POSTCHANGE && freq->old > freq->new) ||
+ (val == CPUFREQ_RESUMECHANGE)) {
+ if (!(freq->flags & CPUFREQ_CONST_LOOPS))
+ cpu_data[freq->cpu].loops_per_jiffy = cpufreq_scale(loops_per_jiffy_ref, ref_freq, freq->new);
+#ifndef CONFIG_SMP
+ if (cpu_khz)
+ cpu_khz = cpufreq_scale(cpu_khz_ref, ref_freq, freq->new);
+ if (use_tsc) {
+ if (!(freq->flags & CPUFREQ_CONST_LOOPS)) {
+ fast_gettimeoffset_quotient = cpufreq_scale(fast_gettimeoffset_ref, freq->new, ref_freq);
+ set_cyc2ns_scale(cpu_khz/1000);
+ }
+ }
+#endif
+ }
+
+ if (val != CPUFREQ_RESUMECHANGE)
+ write_sequnlock_irq(&xtime_lock);
+
+ return 0;
+}
+
+static struct notifier_block time_cpufreq_notifier_block = {
+ .notifier_call = time_cpufreq_notifier
+};
+
+
+static int __init cpufreq_tsc(void)
+{
+ int ret;
+ INIT_WORK(&cpufreq_delayed_get_work, handle_cpufreq_delayed_get, NULL);
+ ret = cpufreq_register_notifier(&time_cpufreq_notifier_block,
+ CPUFREQ_TRANSITION_NOTIFIER);
+ if (!ret)
+ cpufreq_init = 1;
+ return ret;
+}
+core_initcall(cpufreq_tsc);
+
+#else /* CONFIG_CPU_FREQ */
+static inline void cpufreq_delayed_get(void) { return; }
+#endif
+
+static void mark_offset_tsc(void)
+{
+ unsigned long lost,delay;
+ unsigned long delta = last_tsc_low;
+ int count;
+ int countmp;
+ static int count1 = 0;
+ unsigned long long this_offset, last_offset;
+ static int lost_count = 0;
+
+ write_seqlock(&monotonic_lock);
+ last_offset = ((unsigned long long)last_tsc_high<<32)|last_tsc_low;
+ /*
+ * It is important that these two operations happen almost at
+ * the same time. We do the RDTSC stuff first, since it's
+ * faster. To avoid any inconsistencies, we need interrupts
+ * disabled locally.
+ */
+
+ /*
+ * Interrupts are just disabled locally since the timer irq
+ * has the SA_INTERRUPT flag set. -arca
+ */
+
+ /* read Pentium cycle counter */
+
+ rdtsc(last_tsc_low, last_tsc_high);
+
+ spin_lock(&i8253_lock);
+ outb_p(0x00, PIT_MODE); /* latch the count ASAP */
+
+ count = inb_p(PIT_CH0); /* read the latched count */
+ count |= inb(PIT_CH0) << 8;
+
+ /*
+ * VIA686a test code... reset the latch if count > max + 1
+ * from timer_pit.c - cjb
+ */
+ if (count > LATCH) {
+ outb_p(0x34, PIT_MODE);
+ outb_p(LATCH & 0xff, PIT_CH0);
+ outb(LATCH >> 8, PIT_CH0);
+ count = LATCH - 1;
+ }
+
+ spin_unlock(&i8253_lock);
+
+ if (pit_latch_buggy) {
+ /* get center value of last 3 time lutch */
+ if ((count2 >= count && count >= count1)
+ || (count1 >= count && count >= count2)) {
+ count2 = count1; count1 = count;
+ } else if ((count1 >= count2 && count2 >= count)
+ || (count >= count2 && count2 >= count1)) {
+ countmp = count;count = count2;
+ count2 = count1;count1 = countmp;
+ } else {
+ count2 = count1; count1 = count; count = count1;
+ }
+ }
+
+ /* lost tick compensation */
+ delta = last_tsc_low - delta;
+ {
+ register unsigned long eax, edx;
+ eax = delta;
+ __asm__("mull %2"
+ :"=a" (eax), "=d" (edx)
+ :"rm" (fast_gettimeoffset_quotient),
+ "0" (eax));
+ delta = edx;
+ }
+ delta += delay_at_last_interrupt;
+ lost = delta/(1000000/HZ);
+ delay = delta%(1000000/HZ);
+ if (lost >= 2) {
+ jiffies_64 += lost-1;
+
+ /* sanity check to ensure we're not always losing ticks */
+ if (lost_count++ > 100) {
+ printk(KERN_WARNING "Losing too many ticks!\n");
+ printk(KERN_WARNING "TSC cannot be used as a timesource. \n");
+ printk(KERN_WARNING "Possible reasons for this are:\n");
+ printk(KERN_WARNING " You're running with Speedstep,\n");
+ printk(KERN_WARNING " You don't have DMA enabled for your hard disk (see hdparm),\n");
+ printk(KERN_WARNING " Incorrect TSC synchronization on an SMP system (see dmesg).\n");
+ printk(KERN_WARNING "Falling back to a sane timesource now.\n");
+
+ clock_fallback();
+ }
+ /* ... but give the TSC a fair chance */
+ if (lost_count > 25)
+ cpufreq_delayed_get();
+ } else
+ lost_count = 0;
+ /* update the monotonic base value */
+ this_offset = ((unsigned long long)last_tsc_high<<32)|last_tsc_low;
+ monotonic_base += cycles_2_ns(this_offset - last_offset);
+ write_sequnlock(&monotonic_lock);
+
+ /* calculate delay_at_last_interrupt */
+ count = ((LATCH-1) - count) * TICK_SIZE;
+ delay_at_last_interrupt = (count + LATCH/2) / LATCH;
+
+ /* catch corner case where tick rollover occured
+ * between tsc and pit reads (as noted when
+ * usec delta is > 90% # of usecs/tick)
+ */
+ if (lost && abs(delay - delay_at_last_interrupt) > (900000/HZ))
+ jiffies_64++;
+}
+
+static int __init init_tsc(char* override)
+{
+
+ /* check clock override */
+ if (override[0] && strncmp(override,"tsc",3)) {
+#ifdef CONFIG_HPET_TIMER
+ if (is_hpet_enabled()) {
+ printk(KERN_ERR "Warning: clock= override failed. Defaulting to tsc\n");
+ } else
+#endif
+ {
+ return -ENODEV;
+ }
+ }
+
+ /*
+ * If we have APM enabled or the CPU clock speed is variable
+ * (CPU stops clock on HLT or slows clock to save power)
+ * then the TSC timestamps may diverge by up to 1 jiffy from
+ * 'real time' but nothing will break.
+ * The most frequent case is that the CPU is "woken" from a halt
+ * state by the timer interrupt itself, so we get 0 error. In the
+ * rare cases where a driver would "wake" the CPU and request a
+ * timestamp, the maximum error is < 1 jiffy. But timestamps are
+ * still perfectly ordered.
+ * Note that the TSC counter will be reset if APM suspends
+ * to disk; this won't break the kernel, though, 'cuz we're
+ * smart. See arch/i386/kernel/apm.c.
+ */
+ /*
+ * Firstly we have to do a CPU check for chips with
+ * a potentially buggy TSC. At this point we haven't run
+ * the ident/bugs checks so we must run this hook as it
+ * may turn off the TSC flag.
+ *
+ * NOTE: this doesn't yet handle SMP 486 machines where only
+ * some CPU's have a TSC. Thats never worked and nobody has
+ * moaned if you have the only one in the world - you fix it!
+ */
+
+ count2 = LATCH; /* initialize counter for mark_offset_tsc() */
+
+ if (cpu_has_tsc) {
+ unsigned long tsc_quotient;
+#ifdef CONFIG_HPET_TIMER
+ if (is_hpet_enabled()){
+ unsigned long result, remain;
+ printk("Using TSC for gettimeofday\n");
+ tsc_quotient = calibrate_tsc_hpet(NULL);
+ timer_tsc.mark_offset = &mark_offset_tsc_hpet;
+ /*
+ * Math to calculate hpet to usec multiplier
+ * Look for the comments at get_offset_tsc_hpet()
+ */
+ ASM_DIV64_REG(result, remain, hpet_tick,
+ 0, KERNEL_TICK_USEC);
+ if (remain > (hpet_tick >> 1))
+ result++; /* rounding the result */
+
+ hpet_usec_quotient = result;
+ } else
+#endif
+ {
+ tsc_quotient = calibrate_tsc();
+ }
+
+ if (tsc_quotient) {
+ fast_gettimeoffset_quotient = tsc_quotient;
+ use_tsc = 1;
+ /*
+ * We could be more selective here I suspect
+ * and just enable this for the next intel chips ?
+ */
+ /* report CPU clock rate in Hz.
+ * The formula is (10^6 * 2^32) / (2^32 * 1 / (clocks/us)) =
+ * clock/second. Our precision is about 100 ppm.
+ */
+ { unsigned long eax=0, edx=1000;
+ __asm__("divl %2"
+ :"=a" (cpu_khz), "=d" (edx)
+ :"r" (tsc_quotient),
+ "0" (eax), "1" (edx));
+ printk("Detected %lu.%03lu MHz processor.\n", cpu_khz / 1000, cpu_khz % 1000);
+ }
+ set_cyc2ns_scale(cpu_khz/1000);
+ return 0;
+ }
+ }
+ return -ENODEV;
+}
+
+#ifndef CONFIG_X86_TSC
+/* disable flag for tsc. Takes effect by clearing the TSC cpu flag
+ * in cpu/common.c */
+static int __init tsc_setup(char *str)
+{
+ tsc_disable = 1;
+ return 1;
+}
+#else
+static int __init tsc_setup(char *str)
+{
+ printk(KERN_WARNING "notsc: Kernel compiled with CONFIG_X86_TSC, "
+ "cannot disable TSC.\n");
+ return 1;
+}
+#endif
+__setup("notsc", tsc_setup);
+
+
+
+/************************************************************/
+
+/* tsc timer_opts struct */
+static struct timer_opts timer_tsc = {
+ .name = "tsc",
+ .mark_offset = mark_offset_tsc,
+ .get_offset = get_offset_tsc,
+ .monotonic_clock = monotonic_clock_tsc,
+ .delay = delay_tsc,
+};
+
+struct init_timer_opts __initdata timer_tsc_init = {
+ .init = init_tsc,
+ .opts = &timer_tsc,
+};