From: john stultz <johnstul@us.ibm.com>
To: Linus Torvalds <torvalds@transmeta.com>,
Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Dave Jones <davej@suse.de>, george anzinger <george@mvista.com>,
lkml <linux-kernel@vger.kernel.org>, greg kh <greg@kroah.com>,
Patrick Mochel <mochel@osdl.org>
Subject: [PATCH] linux-2.5.41_timer-changes_A4 (3/3 - integration)
Date: 09 Oct 2002 17:13:38 -0700 [thread overview]
Message-ID: <1034208819.21964.1364.camel@cog> (raw)
In-Reply-To: <1034208761.7591.1360.camel@cog>
Linus, All,
This is the final part 3 of 3 of my timer-change patch. Part 3
integrates the moved code (from part 2) into the new infrastructure
(from part 1).
Please apply,
thanks
-john
diff -Nru a/arch/i386/Makefile b/arch/i386/Makefile
--- a/arch/i386/Makefile Wed Oct 9 17:08:33 2002
+++ b/arch/i386/Makefile Wed Oct 9 17:08:33 2002
@@ -53,7 +53,7 @@
libs-y += arch/i386/lib/
core-y += arch/i386/kernel/ arch/i386/mm/ \
- arch/i386/$(MACHINE)/
+ arch/i386/$(MACHINE)/ arch/i386/kernel/timers/
drivers-$(CONFIG_MATH_EMULATION) += arch/i386/math-emu/
drivers-$(CONFIG_PCI) += arch/i386/pci/
diff -Nru a/arch/i386/kernel/time.c b/arch/i386/kernel/time.c
--- a/arch/i386/kernel/time.c Wed Oct 9 17:08:33 2002
+++ b/arch/i386/kernel/time.c Wed Oct 9 17:08:33 2002
@@ -53,6 +53,7 @@
#include <asm/mpspec.h>
#include <asm/uaccess.h>
#include <asm/processor.h>
+#include <asm/timer.h>
#include <linux/mc146818rtc.h>
#include <linux/timex.h>
@@ -78,18 +79,10 @@
spinlock_t rtc_lock = SPIN_LOCK_UNLOCKED;
-
-#define TICK_SIZE (tick_nsec / 1000)
-
spinlock_t i8253_lock = SPIN_LOCK_UNLOCKED;
EXPORT_SYMBOL(i8253_lock);
-#ifndef CONFIG_X86_TSC
-#else
-
-#define do_gettimeoffset() do_fast_gettimeoffset()
-
-#endif
+struct timer_opts* timer;
/*
* This version of gettimeofday has microsecond resolution
@@ -101,7 +94,7 @@
unsigned long usec, sec;
read_lock_irqsave(&xtime_lock, flags);
- usec = do_gettimeoffset();
+ usec = timer->get_offset();
{
unsigned long lost = jiffies - wall_jiffies;
if (lost)
@@ -129,7 +122,7 @@
* wall time. Discover what correction gettimeofday() would have
* made, and then undo it!
*/
- tv->tv_usec -= do_gettimeoffset();
+ tv->tv_usec -= timer->get_offset();
tv->tv_usec -= (jiffies - wall_jiffies) * (1000000 / HZ);
while (tv->tv_usec < 0) {
@@ -295,7 +288,7 @@
*/
write_lock(&xtime_lock);
-
+ timer->mark_offset();
do_timer_interrupt(irq, NULL, regs);
@@ -345,6 +338,7 @@
return mktime(year, mon, day, hour, min, sec);
}
+/* XXX this driverfs stuff should probably go elsewhere later -john */
static struct sys_device device_i8253 = {
.name = "rtc",
.id = 0,
@@ -368,5 +362,6 @@
xtime.tv_nsec = 0;
+ timer = select_timer();
time_init_hook();
}
diff -Nru a/arch/i386/kernel/timers/Makefile b/arch/i386/kernel/timers/Makefile
--- /dev/null Wed Dec 31 16:00:00 1969
+++ b/arch/i386/kernel/timers/Makefile Wed Oct 9 17:08:33 2002
@@ -0,0 +1,10 @@
+#
+# Makefile for x86 timers
+#
+
+obj-y := timer.o
+
+obj-y += timer_tsc.o
+obj-y += timer_pit.o
+
+include $(TOPDIR)/Rules.make
diff -Nru a/arch/i386/kernel/timers/timer.c b/arch/i386/kernel/timers/timer.c
--- a/arch/i386/kernel/timers/timer.c Wed Oct 9 17:08:33 2002
+++ b/arch/i386/kernel/timers/timer.c Wed Oct 9 17:08:33 2002
@@ -2,11 +2,17 @@
#include <asm/timer.h>
/* list of externed timers */
-/* eg: extern struct timer_opts timer_XXX*/;
+#ifndef CONFIG_X86_TSC
+extern struct timer_opts timer_pit;
+#endif
+extern struct timer_opts timer_tsc;
/* list of timers, ordered by preference */
struct timer_opts* timers[] = {
- /* eg: &timer_XXX */
+ &timer_tsc
+#ifndef CONFIG_X86_TSC
+ ,&timer_pit
+#endif
};
#define NR_TIMERS (sizeof(timers)/sizeof(timers[0]))
diff -Nru a/arch/i386/kernel/timers/timer_pit.c b/arch/i386/kernel/timers/timer_pit.c
--- a/arch/i386/kernel/timers/timer_pit.c Wed Oct 9 17:08:33 2002
+++ b/arch/i386/kernel/timers/timer_pit.c Wed Oct 9 17:08:33 2002
@@ -1,3 +1,28 @@
+/*
+ * 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 <asm/timer.h>
+#include <asm/io.h>
+
+extern spinlock_t i8259A_lock;
+extern spinlock_t i8253_lock;
+#include "do_timer.h"
+
+static int init_pit(void)
+{
+ return 1;
+}
+
+static void mark_offset_pit(void)
+{
+ /* nothing needed */
+}
+
/* This function must be called with interrupts disabled
* It was inspired by Steve McCanne's microtime-i386 for BSD. -- jrs
@@ -31,7 +56,7 @@
* comp.protocols.time.ntp!
*/
-static unsigned long do_slow_gettimeoffset(void)
+static unsigned long get_offset_pit(void)
{
int count;
@@ -94,4 +119,10 @@
return count;
}
-static unsigned long (*do_gettimeoffset)(void) = do_slow_gettimeoffset;
+
+/* tsc timer_opts struct */
+struct timer_opts timer_pit = {
+ init: init_pit,
+ mark_offset: mark_offset_pit,
+ get_offset: get_offset_pit
+};
diff -Nru a/arch/i386/kernel/timers/timer_tsc.c b/arch/i386/kernel/timers/timer_tsc.c
--- a/arch/i386/kernel/timers/timer_tsc.c Wed Oct 9 17:08:33 2002
+++ b/arch/i386/kernel/timers/timer_tsc.c Wed Oct 9 17:08:33 2002
@@ -1,3 +1,19 @@
+/*
+ * 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 <asm/timer.h>
+#include <asm/io.h>
+
+extern int x86_udelay_tsc;
+extern spinlock_t i8253_lock;
+
+static int use_tsc;
/* Number of usecs that the last interrupt was delayed */
static int delay_at_last_interrupt;
@@ -10,7 +26,7 @@
*/
unsigned long fast_gettimeoffset_quotient;
-static inline unsigned long do_fast_gettimeoffset(void)
+static unsigned long get_offset_tsc(void)
{
register unsigned long eax, edx;
@@ -39,36 +55,35 @@
return delay_at_last_interrupt + edx;
}
+static void mark_offset_tsc(void)
+{
+ int count;
+ /*
+ * 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.
+ */
-
-if (use_tsc)
- {
- /*
- * 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
- */
+ /*
+ * Interrupts are just disabled locally since the timer irq
+ * has the SA_INTERRUPT flag set. -arca
+ */
- /* read Pentium cycle counter */
+ /* read Pentium cycle counter */
- rdtscl(last_tsc_low);
+ rdtscl(last_tsc_low);
- spin_lock(&i8253_lock);
- outb_p(0x00, 0x43); /* latch the count ASAP */
+ spin_lock(&i8253_lock);
+ outb_p(0x00, 0x43); /* latch the count ASAP */
- count = inb_p(0x40); /* read the latched count */
- count |= inb(0x40) << 8;
- spin_unlock(&i8253_lock);
+ count = inb_p(0x40); /* read the latched count */
+ count |= inb(0x40) << 8;
+ spin_unlock(&i8253_lock);
- count = ((LATCH-1) - count) * TICK_SIZE;
- delay_at_last_interrupt = (count + LATCH/2) / LATCH;
- }
+ count = ((LATCH-1) - count) * TICK_SIZE;
+ delay_at_last_interrupt = (count + LATCH/2) / LATCH;
+}
/* ------ Calibrate the TSC -------
@@ -83,7 +98,6 @@
#define CALIBRATE_LATCH (5 * LATCH)
#define CALIBRATE_TIME (5 * 1000020/HZ)
-#ifdef CONFIG_X86_TSC
static unsigned long __init calibrate_tsc(void)
{
/* Set the Gate high, disable speaker */
@@ -148,7 +162,6 @@
bad_ctc:
return 0;
}
-#endif /* CONFIG_X86_TSC */
#ifdef CONFIG_CPU_FREQ
@@ -196,26 +209,22 @@
#endif
-
-#ifdef CONFIG_X86_TSC
- extern int x86_udelay_tsc;
-#endif
-
-/*
- * 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.
- */
-#ifdef CONFIG_X86_TSC
+static int init_tsc(void)
+{
+ /*
+ * 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
@@ -239,9 +248,6 @@
* and just enable this for the next intel chips ?
*/
x86_udelay_tsc = 1;
-#ifndef do_gettimeoffset
- do_gettimeoffset = do_fast_gettimeoffset;
-#endif
/* report CPU clock rate in Hz.
* The formula is (10^6 * 2^32) / (2^32 * 1 / (clocks/us)) =
@@ -257,6 +263,17 @@
#ifdef CONFIG_CPU_FREQ
cpufreq_register_notifier(&time_cpufreq_notifier_block, CPUFREQ_TRANSITION_NOTIFIER);
#endif
+ return 1;
}
}
-#endif /* CONFIG_X86_TSC */
+ return 0;
+}
+
+/************************************************************/
+
+/* tsc timer_opts struct */
+struct timer_opts timer_tsc = {
+ init: init_tsc,
+ mark_offset: mark_offset_tsc,
+ get_offset: get_offset_tsc
+};
diff -Nru a/include/asm-i386/timer.h b/include/asm-i386/timer.h
--- a/include/asm-i386/timer.h Wed Oct 9 17:08:33 2002
+++ b/include/asm-i386/timer.h Wed Oct 9 17:08:33 2002
@@ -9,6 +9,6 @@
/* called by gettimeofday. returns # ms since the last timer interrupt */
unsigned long (*get_offset)(void);
};
-
+#define TICK_SIZE (tick_nsec / 1000)
struct timer_opts* select_timer(void);
#endif
next prev parent reply other threads:[~2002-10-10 0:14 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-10-10 0:11 [PATCH] linux-2.5.41_timer-changes_A4 (1/3 - infrastructure) john stultz
2002-10-10 0:12 ` [PATCH] linux-2.5.41_timer-changes_A4 (2/3 - bulk move) john stultz
2002-10-10 0:13 ` john stultz [this message]
2002-10-10 1:27 ` [RFC][PATCH] linux-2.5.41_cyclone-timer_B2 john stultz
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