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Message-Id: <E1QJQWD-0000Lz-Ou@rmk-PC.arm.linux.org.uk>
Date: Mon, 09 May 2011 14:29:01 +0100
From: Russell King - ARM Linux <linux@....linux.org.uk>
To: LKML <linux-kernel@...r.kernel.org>,
Thomas Gleixner <tglx@...utronix.de>,
John Stultz <johnstul@...ibm.com>
Subject: [PATCH 2/4] clocksource: convert footbridge to generic i8253
clocksource
Convert the footbridge isa-timer code to use generic i8253 clocksource.
Signed-off-by: Russell King <rmk+kernel@....linux.org.uk>
---
arch/arm/include/asm/i8253.h | 15 +++++++++++
arch/arm/mach-footbridge/Kconfig | 2 +
arch/arm/mach-footbridge/isa-timer.c | 45 +++-------------------------------
include/linux/clocksource.h | 2 +
4 files changed, 23 insertions(+), 41 deletions(-)
create mode 100644 arch/arm/include/asm/i8253.h
diff --git a/arch/arm/include/asm/i8253.h b/arch/arm/include/asm/i8253.h
new file mode 100644
index 0000000..70656b6
--- /dev/null
+++ b/arch/arm/include/asm/i8253.h
@@ -0,0 +1,15 @@
+#ifndef __ASMARM_I8253_H
+#define __ASMARM_I8253_H
+
+/* i8253A PIT registers */
+#define PIT_MODE 0x43
+#define PIT_CH0 0x40
+
+#define PIT_LATCH ((PIT_TICK_RATE + HZ / 2) / HZ)
+
+extern raw_spinlock_t i8253_lock;
+
+#define outb_pit outb_p
+#define inb_pit inb_p
+
+#endif
diff --git a/arch/arm/mach-footbridge/Kconfig b/arch/arm/mach-footbridge/Kconfig
index bdd2579..46adca0 100644
--- a/arch/arm/mach-footbridge/Kconfig
+++ b/arch/arm/mach-footbridge/Kconfig
@@ -4,6 +4,7 @@ menu "Footbridge Implementations"
config ARCH_CATS
bool "CATS"
+ select CLKSRC_I8253
select FOOTBRIDGE_HOST
select ISA
select ISA_DMA
@@ -59,6 +60,7 @@ config ARCH_EBSA285_HOST
config ARCH_NETWINDER
bool "NetWinder"
+ select CLKSRC_I8253
select FOOTBRIDGE_HOST
select ISA
select ISA_DMA
diff --git a/arch/arm/mach-footbridge/isa-timer.c b/arch/arm/mach-footbridge/isa-timer.c
index 441c6ce..7020f1a 100644
--- a/arch/arm/mach-footbridge/isa-timer.c
+++ b/arch/arm/mach-footbridge/isa-timer.c
@@ -10,53 +10,16 @@
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/io.h>
+#include <linux/spinlock.h>
#include <linux/timex.h>
#include <asm/irq.h>
-
+#include <asm/i8253.h>
#include <asm/mach/time.h>
#include "common.h"
-#define PIT_MODE 0x43
-#define PIT_CH0 0x40
-
-#define PIT_LATCH ((PIT_TICK_RATE + HZ / 2) / HZ)
-
-static cycle_t pit_read(struct clocksource *cs)
-{
- unsigned long flags;
- static int old_count;
- static u32 old_jifs;
- int count;
- u32 jifs;
-
- raw_local_irq_save(flags);
-
- jifs = jiffies;
- outb_p(0x00, PIT_MODE); /* latch the count */
- count = inb_p(PIT_CH0); /* read the latched count */
- count |= inb_p(PIT_CH0) << 8;
-
- if (count > old_count && jifs == old_jifs)
- count = old_count;
-
- old_count = count;
- old_jifs = jifs;
-
- raw_local_irq_restore(flags);
-
- count = (PIT_LATCH - 1) - count;
-
- return (cycle_t)(jifs * PIT_LATCH) + count;
-}
-
-static struct clocksource pit_cs = {
- .name = "pit",
- .rating = 110,
- .read = pit_read,
- .mask = CLOCKSOURCE_MASK(32),
-};
+DEFINE_RAW_SPINLOCK(i8253_lock);
static void pit_set_mode(enum clock_event_mode mode,
struct clock_event_device *evt)
@@ -121,7 +84,7 @@ static void __init isa_timer_init(void)
pit_ce.max_delta_ns = clockevent_delta2ns(0x7fff, &pit_ce);
pit_ce.min_delta_ns = clockevent_delta2ns(0x000f, &pit_ce);
- clocksource_register_hz(&pit_cs, PIT_TICK_RATE);
+ clocksource_i8253_init();
setup_irq(pit_ce.irq, &pit_timer_irq);
clockevents_register_device(&pit_ce);
diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h
index c37b21a..f13469b 100644
--- a/include/linux/clocksource.h
+++ b/include/linux/clocksource.h
@@ -341,4 +341,6 @@ static inline void update_vsyscall_tz(void)
extern void timekeeping_notify(struct clocksource *clock);
+extern int clocksource_i8253_init(void);
+
#endif /* _LINUX_CLOCKSOURCE_H */
--
1.7.4.4
--
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