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-rw-r--r--arch/i386/kernel/Makefile1
-rw-r--r--arch/i386/kernel/hpet.c67
-rw-r--r--arch/i386/kernel/i8253.c53
-rw-r--r--arch/i386/kernel/time.c3
-rw-r--r--arch/i386/kernel/tsc.c161
5 files changed, 282 insertions, 3 deletions
diff --git a/arch/i386/kernel/Makefile b/arch/i386/kernel/Makefile
index f238cb6274e..0fac85df64f 100644
--- a/arch/i386/kernel/Makefile
+++ b/arch/i386/kernel/Makefile
@@ -36,6 +36,7 @@ obj-$(CONFIG_EFI) += efi.o efi_stub.o
obj-$(CONFIG_DOUBLEFAULT) += doublefault.o
obj-$(CONFIG_VM86) += vm86.o
obj-$(CONFIG_EARLY_PRINTK) += early_printk.o
+obj-$(CONFIG_HPET_TIMER) += hpet.o
EXTRA_AFLAGS := -traditional
diff --git a/arch/i386/kernel/hpet.c b/arch/i386/kernel/hpet.c
new file mode 100644
index 00000000000..91a5bdd9f60
--- /dev/null
+++ b/arch/i386/kernel/hpet.c
@@ -0,0 +1,67 @@
+#include <linux/clocksource.h>
+#include <linux/errno.h>
+#include <linux/hpet.h>
+#include <linux/init.h>
+
+#include <asm/hpet.h>
+#include <asm/io.h>
+
+#define HPET_MASK 0xFFFFFFFF
+#define HPET_SHIFT 22
+
+/* FSEC = 10^-15 NSEC = 10^-9 */
+#define FSEC_PER_NSEC 1000000
+
+static void *hpet_ptr;
+
+static cycle_t read_hpet(void)
+{
+ return (cycle_t)readl(hpet_ptr);
+}
+
+static struct clocksource clocksource_hpet = {
+ .name = "hpet",
+ .rating = 250,
+ .read = read_hpet,
+ .mask = (cycle_t)HPET_MASK,
+ .mult = 0, /* set below */
+ .shift = HPET_SHIFT,
+ .is_continuous = 1,
+};
+
+static int __init init_hpet_clocksource(void)
+{
+ unsigned long hpet_period;
+ void __iomem* hpet_base;
+ u64 tmp;
+
+ if (!hpet_address)
+ return -ENODEV;
+
+ /* calculate the hpet address: */
+ hpet_base =
+ (void __iomem*)ioremap_nocache(hpet_address, HPET_MMAP_SIZE);
+ hpet_ptr = hpet_base + HPET_COUNTER;
+
+ /* calculate the frequency: */
+ hpet_period = readl(hpet_base + HPET_PERIOD);
+
+ /*
+ * hpet period is in femto seconds per cycle
+ * so we need to convert this to ns/cyc units
+ * aproximated by mult/2^shift
+ *
+ * fsec/cyc * 1nsec/1000000fsec = nsec/cyc = mult/2^shift
+ * fsec/cyc * 1ns/1000000fsec * 2^shift = mult
+ * fsec/cyc * 2^shift * 1nsec/1000000fsec = mult
+ * (fsec/cyc << shift)/1000000 = mult
+ * (hpet_period << shift)/FSEC_PER_NSEC = mult
+ */
+ tmp = (u64)hpet_period << HPET_SHIFT;
+ do_div(tmp, FSEC_PER_NSEC);
+ clocksource_hpet.mult = (u32)tmp;
+
+ return register_clocksource(&clocksource_hpet);
+}
+
+module_init(init_hpet_clocksource);
diff --git a/arch/i386/kernel/i8253.c b/arch/i386/kernel/i8253.c
index 29cb2eb3436..a276bceade6 100644
--- a/arch/i386/kernel/i8253.c
+++ b/arch/i386/kernel/i8253.c
@@ -2,6 +2,7 @@
* i8253.c 8253/PIT functions
*
*/
+#include <linux/clocksource.h>
#include <linux/spinlock.h>
#include <linux/jiffies.h>
#include <linux/sysdev.h>
@@ -30,3 +31,55 @@ void setup_pit_timer(void)
outb(LATCH >> 8 , PIT_CH0); /* MSB */
spin_unlock_irqrestore(&i8253_lock, flags);
}
+
+/*
+ * Since the PIT overflows every tick, its not very useful
+ * to just read by itself. So use jiffies to emulate a free
+ * running counter:
+ */
+static cycle_t pit_read(void)
+{
+ unsigned long flags;
+ int count;
+ u64 jifs;
+
+ spin_lock_irqsave(&i8253_lock, flags);
+ outb_p(0x00, PIT_MODE); /* latch the count ASAP */
+ count = inb_p(PIT_CH0); /* read the latched count */
+ 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;
+ }
+ spin_unlock_irqrestore(&i8253_lock, flags);
+
+ jifs = jiffies_64;
+
+ jifs -= INITIAL_JIFFIES;
+ count = (LATCH-1) - count;
+
+ return (cycle_t)(jifs * LATCH) + count;
+}
+
+static struct clocksource clocksource_pit = {
+ .name = "pit",
+ .rating = 110,
+ .read = pit_read,
+ .mask = (cycle_t)-1,
+ .mult = 0,
+ .shift = 20,
+};
+
+static int __init init_pit_clocksource(void)
+{
+ if (num_possible_cpus() > 4) /* PIT does not scale! */
+ return 0;
+
+ clocksource_pit.mult = clocksource_hz2mult(CLOCK_TICK_RATE, 20);
+ return register_clocksource(&clocksource_pit);
+}
+module_init(init_pit_clocksource);
diff --git a/arch/i386/kernel/time.c b/arch/i386/kernel/time.c
index 2a6ab86ffc1..5f43d041012 100644
--- a/arch/i386/kernel/time.c
+++ b/arch/i386/kernel/time.c
@@ -82,9 +82,6 @@ extern unsigned long wall_jiffies;
DEFINE_SPINLOCK(rtc_lock);
EXPORT_SYMBOL(rtc_lock);
-/* XXX - necessary to keep things compiling. to be removed later */
-u32 pmtmr_ioport;
-
/*
* This is a special lock that is owned by the CPU and holds the index
* register we are working with. It is required for NMI access to the
diff --git a/arch/i386/kernel/tsc.c b/arch/i386/kernel/tsc.c
index 96b307495e5..7713f86389a 100644
--- a/arch/i386/kernel/tsc.c
+++ b/arch/i386/kernel/tsc.c
@@ -4,11 +4,14 @@
* See comments there for proper credits.
*/
+#include <linux/clocksource.h>
#include <linux/workqueue.h>
#include <linux/cpufreq.h>
#include <linux/jiffies.h>
#include <linux/init.h>
+#include <linux/dmi.h>
+#include <asm/delay.h>
#include <asm/tsc.h>
#include <asm/delay.h>
#include <asm/io.h>
@@ -315,3 +318,161 @@ static int __init cpufreq_tsc(void)
core_initcall(cpufreq_tsc);
#endif
+
+/* clock source code */
+
+static unsigned long current_tsc_khz = 0;
+static int tsc_update_callback(void);
+
+static cycle_t read_tsc(void)
+{
+ cycle_t ret;
+
+ rdtscll(ret);
+
+ return ret;
+}
+
+static struct clocksource clocksource_tsc = {
+ .name = "tsc",
+ .rating = 300,
+ .read = read_tsc,
+ .mask = (cycle_t)-1,
+ .mult = 0, /* to be set */
+ .shift = 22,
+ .update_callback = tsc_update_callback,
+ .is_continuous = 1,
+};
+
+static int tsc_update_callback(void)
+{
+ int change = 0;
+
+ /* check to see if we should switch to the safe clocksource: */
+ if (clocksource_tsc.rating != 50 && check_tsc_unstable()) {
+ clocksource_tsc.rating = 50;
+ reselect_clocksource();
+ change = 1;
+ }
+
+ /* only update if tsc_khz has changed: */
+ if (current_tsc_khz != tsc_khz) {
+ current_tsc_khz = tsc_khz;
+ clocksource_tsc.mult = clocksource_khz2mult(current_tsc_khz,
+ clocksource_tsc.shift);
+ change = 1;
+ }
+
+ return change;
+}
+
+static int __init dmi_mark_tsc_unstable(struct dmi_system_id *d)
+{
+ printk(KERN_NOTICE "%s detected: marking TSC unstable.\n",
+ d->ident);
+ mark_tsc_unstable();
+ return 0;
+}
+
+/* List of systems that have known TSC problems */
+static struct dmi_system_id __initdata bad_tsc_dmi_table[] = {
+ {
+ .callback = dmi_mark_tsc_unstable,
+ .ident = "IBM Thinkpad 380XD",
+ .matches = {
+ DMI_MATCH(DMI_BOARD_VENDOR, "IBM"),
+ DMI_MATCH(DMI_BOARD_NAME, "2635FA0"),
+ },
+ },
+ {}
+};
+
+#define TSC_FREQ_CHECK_INTERVAL (10*MSEC_PER_SEC) /* 10sec in MS */
+static struct timer_list verify_tsc_freq_timer;
+
+/* XXX - Probably should add locking */
+static void verify_tsc_freq(unsigned long unused)
+{
+ static u64 last_tsc;
+ static unsigned long last_jiffies;
+
+ u64 now_tsc, interval_tsc;
+ unsigned long now_jiffies, interval_jiffies;
+
+
+ if (check_tsc_unstable())
+ return;
+
+ rdtscll(now_tsc);
+ now_jiffies = jiffies;
+
+ if (!last_jiffies) {
+ goto out;
+ }
+
+ interval_jiffies = now_jiffies - last_jiffies;
+ interval_tsc = now_tsc - last_tsc;
+ interval_tsc *= HZ;
+ do_div(interval_tsc, cpu_khz*1000);
+
+ if (interval_tsc < (interval_jiffies * 3 / 4)) {
+ printk("TSC appears to be running slowly. "
+ "Marking it as unstable\n");
+ mark_tsc_unstable();
+ return;
+ }
+
+out:
+ last_tsc = now_tsc;
+ last_jiffies = now_jiffies;
+ /* set us up to go off on the next interval: */
+ mod_timer(&verify_tsc_freq_timer,
+ jiffies + msecs_to_jiffies(TSC_FREQ_CHECK_INTERVAL));
+}
+
+/*
+ * Make an educated guess if the TSC is trustworthy and synchronized
+ * over all CPUs.
+ */
+static __init int unsynchronized_tsc(void)
+{
+ /*
+ * Intel systems are normally all synchronized.
+ * Exceptions must mark TSC as unstable:
+ */
+ if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL)
+ return 0;
+
+ /* assume multi socket systems are not synchronized: */
+ return num_possible_cpus() > 1;
+}
+
+static int __init init_tsc_clocksource(void)
+{
+
+ if (cpu_has_tsc && tsc_khz && !tsc_disable) {
+ /* check blacklist */
+ dmi_check_system(bad_tsc_dmi_table);
+
+ if (unsynchronized_tsc()) /* mark unstable if unsynced */
+ mark_tsc_unstable();
+ current_tsc_khz = tsc_khz;
+ clocksource_tsc.mult = clocksource_khz2mult(current_tsc_khz,
+ clocksource_tsc.shift);
+ /* lower the rating if we already know its unstable: */
+ if (check_tsc_unstable())
+ clocksource_tsc.rating = 50;
+
+ init_timer(&verify_tsc_freq_timer);
+ verify_tsc_freq_timer.function = verify_tsc_freq;
+ verify_tsc_freq_timer.expires =
+ jiffies + msecs_to_jiffies(TSC_FREQ_CHECK_INTERVAL);
+ add_timer(&verify_tsc_freq_timer);
+
+ return register_clocksource(&clocksource_tsc);
+ }
+
+ return 0;
+}
+
+module_init(init_tsc_clocksource);
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-27 04:51:25 +0000