Andrew, All,
This patch implements the time sources for i386 (acpi_pm,
cyclone, hpet, pit, and tsc). The patch should apply on top of the
timeofday-arch-i386-part6 patch.
The patch should be fairly straight forward, only adding the new
clocksources.
Andrew, please consider for inclusion into your tree.
thanks
-john
Signed-off-by: John Stultz <[email protected]>
arch/i386/kernel/Makefile | 1
arch/i386/kernel/hpet.c | 69 +++++++++++++++++++++++
arch/i386/kernel/i8253.c | 60 ++++++++++++++++++++
arch/i386/kernel/tsc.c | 85 ++++++++++++++++++++++++++++-
drivers/Makefile | 1
drivers/clocksource/Makefile | 2
drivers/clocksource/acpi_pm.c | 123 ++++++++++++++++++++++++++++++++++++++++++
drivers/clocksource/cyclone.c | 121 +++++++++++++++++++++++++++++++++++++++++
8 files changed, 461 insertions(+), 1 deletion(-)
linux-2.6.15-rc5_timeofday-clocks-i386_B14.patch
============================================
diff --git a/arch/i386/kernel/Makefile b/arch/i386/kernel/Makefile
index 5d1d9c9..984d488 100644
--- a/arch/i386/kernel/Makefile
+++ b/arch/i386/kernel/Makefile
@@ -33,6 +33,7 @@ obj-$(CONFIG_ACPI_SRAT) += srat.o
obj-$(CONFIG_HPET_TIMER) += time_hpet.o
obj-$(CONFIG_EFI) += efi.o efi_stub.o
obj-$(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 0000000..a620d15
--- /dev/null
+++ b/arch/i386/kernel/hpet.c
@@ -0,0 +1,69 @@
+#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);
+}
+
+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;
+
+ register_clocksource(&clocksource_hpet);
+
+ return 0;
+}
+
+module_init(init_hpet_clocksource);
diff --git a/arch/i386/kernel/i8253.c b/arch/i386/kernel/i8253.c
index e4b7f7d..5e62edd 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>
@@ -57,3 +58,62 @@ static int __init init_timer_sysfs(void)
}
device_initcall(init_timer_sysfs);
+
+
+/*
+ * 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, seq;
+ int count;
+ u64 jifs;
+
+ do {
+ seq = read_seqbegin(&xtime_lock);
+
+ 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;
+ } while (read_seqretry(&xtime_lock, seq));
+
+ 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);
+ register_clocksource(&clocksource_pit);
+
+ return 0;
+}
+module_init(init_pit_clocksource);
diff --git a/arch/i386/kernel/tsc.c b/arch/i386/kernel/tsc.c
index bd04f92..d9004dc 100644
--- a/arch/i386/kernel/tsc.c
+++ b/arch/i386/kernel/tsc.c
@@ -4,13 +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 <asm/tsc.h>
#include <asm/delay.h>
+#include <asm/tsc.h>
#include <asm/io.h>
#include "mach_timer.h"
@@ -302,3 +303,85 @@ 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;
+}
+
+/*
+ * 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;
+}
+
+/* NUMAQ can't use TSC: */
+static int __init init_tsc_clocksource(void)
+{
+ /* TSC initialization is done in arch/i386/kernel/tsc.c */
+ if (cpu_has_tsc && tsc_khz && !tsc_disable) {
+ if (unsynchronized_tsc()) /* lower rating if unsynced */
+ mark_tsc_unstable();
+ current_tsc_khz = tsc_khz;
+ clocksource_tsc.mult = clocksource_khz2mult(current_tsc_khz,
+ clocksource_tsc.shift);
+ register_clocksource(&clocksource_tsc);
+ }
+
+ return 0;
+}
+
+module_init(init_tsc_clocksource);
diff --git a/drivers/Makefile b/drivers/Makefile
index ea410b6..b250984 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -70,3 +70,4 @@ obj-$(CONFIG_SGI_IOC4) += sn/
obj-y += firmware/
obj-$(CONFIG_CRYPTO) += crypto/
obj-$(CONFIG_SUPERH) += sh/
+obj-$(CONFIG_GENERIC_TIME) += clocksource/
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
new file mode 100644
index 0000000..6e98a5e
--- /dev/null
+++ b/drivers/clocksource/Makefile
@@ -0,0 +1,2 @@
+obj-$(CONFIG_X86_CYCLONE_TIMER) += cyclone.o
+obj-$(CONFIG_ACPI) += acpi_pm.o
diff --git a/drivers/clocksource/acpi_pm.c b/drivers/clocksource/acpi_pm.c
new file mode 100644
index 0000000..e5bc091
--- /dev/null
+++ b/drivers/clocksource/acpi_pm.c
@@ -0,0 +1,123 @@
+/*
+ * linux/drivers/clocksource/acpi_pm.c
+ *
+ * This file contains the ACPI PM based clocksource.
+ *
+ * This code was largely moved from the i386 timer_pm.c file
+ * which was (C) Dominik Brodowski <[email protected]> 2003
+ * and contained the following comments:
+ *
+ * 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/clocksource.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <asm/io.h>
+
+/* Number of PMTMR ticks expected during calibration run */
+#define PMTMR_TICKS_PER_SEC 3579545
+
+#if (defined(CONFIG_X86) && (!defined(CONFIG_X86_64)))
+# include "mach_timer.h"
+# define PMTMR_EXPECTED_RATE ((PMTMR_TICKS_PER_SEC*CALIBRATE_TIME_MSEC)/1000)
+#endif
+
+/*
+ * The I/O port the PMTMR resides at.
+ * The location is detected during setup_arch(),
+ * in arch/i386/acpi/boot.c
+ */
+extern u32 acpi_pmtmr_ioport;
+extern int acpi_pmtmr_buggy;
+
+#define ACPI_PM_MASK 0xFFFFFF /* limit it to 24 bits */
+
+static inline u32 read_pmtmr(void)
+{
+ /* mask the output to 24 bits */
+ return inl(acpi_pmtmr_ioport) & ACPI_PM_MASK;
+}
+
+static cycle_t acpi_pm_read_verified(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 clock
+ * source is not latched, so you must read it multiple
+ * times to ensure a safe value is read:
+ */
+ do {
+ v1 = read_pmtmr();
+ v2 = read_pmtmr();
+ v3 = read_pmtmr();
+ } while ((v1 > v2 && v1 < v3) || (v2 > v3 && v2 < v1)
+ || (v3 > v1 && v3 < v2));
+
+ return (cycle_t)v2;
+}
+
+static cycle_t acpi_pm_read(void)
+{
+ return (cycle_t)read_pmtmr();
+}
+
+struct clocksource clocksource_acpi_pm = {
+ .name = "acpi_pm",
+ .rating = 200,
+ .read = acpi_pm_read,
+ .mask = (cycle_t)ACPI_PM_MASK,
+ .mult = 0, /*to be caluclated*/
+ .shift = 22,
+ .is_continuous = 1,
+};
+
+static int __init init_acpi_pm_clocksource(void)
+{
+ u32 value1, value2;
+ unsigned int i;
+
+ if (!acpi_pmtmr_ioport)
+ return -ENODEV;
+
+ clocksource_acpi_pm.mult = clocksource_hz2mult(PMTMR_TICKS_PER_SEC,
+ clocksource_acpi_pm.shift);
+
+ /* "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:
+
+ /* check to see if pmtmr is known buggy: */
+ if (acpi_pmtmr_buggy) {
+ clocksource_acpi_pm.read = acpi_pm_read_verified;
+ clocksource_acpi_pm.rating = 110;
+ }
+
+ register_clocksource(&clocksource_acpi_pm);
+
+ return 0;
+}
+
+module_init(init_acpi_pm_clocksource);
diff --git a/drivers/clocksource/cyclone.c b/drivers/clocksource/cyclone.c
new file mode 100644
index 0000000..168e78b
--- /dev/null
+++ b/drivers/clocksource/cyclone.c
@@ -0,0 +1,121 @@
+#include <linux/clocksource.h>
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/timex.h>
+#include <linux/init.h>
+
+#include <asm/pgtable.h>
+#include <asm/io.h>
+
+#include "mach_timer.h"
+
+#define CYCLONE_CBAR_ADDR 0xFEB00CD0 /* base address ptr */
+#define CYCLONE_PMCC_OFFSET 0x51A0 /* offset to control register */
+#define CYCLONE_MPCS_OFFSET 0x51A8 /* offset to select register */
+#define CYCLONE_MPMC_OFFSET 0x51D0 /* offset to count register */
+#define CYCLONE_TIMER_FREQ 99780000 /* 100Mhz, but not really */
+#define CYCLONE_TIMER_MASK 0xFFFFFFFF /* 32 bit mask */
+
+int use_cyclone = 0;
+static void __iomem *cyclone_ptr;
+
+static cycle_t read_cyclone(void)
+{
+ return (cycle_t)readl(cyclone_ptr);
+}
+
+struct clocksource clocksource_cyclone = {
+ .name = "cyclone",
+ .rating = 250,
+ .read = read_cyclone,
+ .mask = (cycle_t)CYCLONE_TIMER_MASK,
+ .mult = 10,
+ .shift = 0,
+ .is_continuous = 1,
+};
+
+static int __init init_cyclone_clocksource(void)
+{
+ unsigned long base; /* saved value from CBAR */
+ unsigned long offset;
+ u32 __iomem* volatile cyclone_timer; /* Cyclone MPMC0 register */
+ u32 __iomem* reg;
+ int i;
+
+ /* 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: */
+ offset = CYCLONE_CBAR_ADDR;
+ reg = ioremap_nocache(offset, sizeof(reg));
+ if (!reg) {
+ printk(KERN_ERR "Summit chipset: Could not find valid CBAR register.\n");
+ return -ENODEV;
+ }
+ /* even on 64bit systems, this is only 32bits: */
+ base = readl(reg);
+ if (!base) {
+ printk(KERN_ERR "Summit chipset: Could not find valid CBAR value.\n");
+ return -ENODEV;
+ }
+ iounmap(reg);
+
+ /* setup PMCC: */
+ offset = base + CYCLONE_PMCC_OFFSET;
+ reg = ioremap_nocache(offset, sizeof(reg));
+ if (!reg) {
+ printk(KERN_ERR "Summit chipset: Could not find valid PMCC register.\n");
+ return -ENODEV;
+ }
+ writel(0x00000001,reg);
+ iounmap(reg);
+
+ /* setup MPCS: */
+ offset = base + CYCLONE_MPCS_OFFSET;
+ reg = ioremap_nocache(offset, sizeof(reg));
+ if (!reg) {
+ printk(KERN_ERR "Summit chipset: Could not find valid MPCS register.\n");
+ return -ENODEV;
+ }
+ writel(0x00000001,reg);
+ iounmap(reg);
+
+ /* map in cyclone_timer: */
+ offset = base + CYCLONE_MPMC_OFFSET;
+ cyclone_timer = ioremap_nocache(offset, sizeof(u64));
+ 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 = readl(cyclone_timer);
+ int stall = 100;
+
+ while (stall--)
+ barrier();
+
+ if (readl(cyclone_timer) == old) {
+ printk(KERN_ERR "Summit chipset: Counter not counting! DISABLED\n");
+ iounmap(cyclone_timer);
+ cyclone_timer = NULL;
+ return -ENODEV;
+ }
+ }
+ cyclone_ptr = cyclone_timer;
+
+ /* sort out mult/shift values: */
+ clocksource_cyclone.shift = 22;
+ clocksource_cyclone.mult = clocksource_hz2mult(CYCLONE_TIMER_FREQ,
+ clocksource_cyclone.shift);
+
+ register_clocksource(&clocksource_cyclone);
+
+ return 0;
+}
+
+module_init(init_cyclone_clocksource);
-
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