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authorAndrew Victor <andrew@sanpeople.com>2006-12-01 09:04:47 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2006-12-01 13:53:50 +0000
commit1a0ed732afdbd4b960a4b93f78fddc71b8076e61 (patch)
treecdda659c8f9020ea22fe18ed83ca021233807b4a /arch/arm/mach-at91rm9200
parenteaa595cb881bba043e79638c37cb357f296a7714 (diff)
downloadlinux-2.6.34-ux500-1a0ed732afdbd4b960a4b93f78fddc71b8076e61.tar.gz
[ARM] 3949/2: AT91: SAM9 timer driver
Add support for the timer on the Atmel AT91SAM9261 and AT91SAM9260 processors. Signed-off-by: Andrew Victor <andrew@sanpeople.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/mach-at91rm9200')
-rw-r--r--arch/arm/mach-at91rm9200/Makefile4
-rw-r--r--arch/arm/mach-at91rm9200/at91sam926x_time.c114
2 files changed, 116 insertions, 2 deletions
diff --git a/arch/arm/mach-at91rm9200/Makefile b/arch/arm/mach-at91rm9200/Makefile
index 40e89bf459f..b8684ba60ce 100644
--- a/arch/arm/mach-at91rm9200/Makefile
+++ b/arch/arm/mach-at91rm9200/Makefile
@@ -11,8 +11,8 @@ obj-$(CONFIG_PM) += pm.o
# CPU-specific support
obj-$(CONFIG_ARCH_AT91RM9200) += at91rm9200.o at91rm9200_time.o at91rm9200_devices.c
-obj-$(CONFIG_ARCH_AT91SAM9260) += at91sam9260.o
-obj-$(CONFIG_ARCH_AT91SAM9261) += at91sam9261.o
+obj-$(CONFIG_ARCH_AT91SAM9260) += at91sam9260.o at91sam926x_time.o
+obj-$(CONFIG_ARCH_AT91SAM9261) += at91sam9261.o at91sam926x_time.o
# AT91RM9200 board-specific support
obj-$(CONFIG_MACH_ONEARM) += board-1arm.o
diff --git a/arch/arm/mach-at91rm9200/at91sam926x_time.c b/arch/arm/mach-at91rm9200/at91sam926x_time.c
new file mode 100644
index 00000000000..99df5f6ee42
--- /dev/null
+++ b/arch/arm/mach-at91rm9200/at91sam926x_time.c
@@ -0,0 +1,114 @@
+/*
+ * linux/arch/arm/mach-at91rm9200/at91sam926x_time.c
+ *
+ * Copyright (C) 2005-2006 M. Amine SAYA, ATMEL Rousset, France
+ * Revision 2005 M. Nicolas Diremdjian, ATMEL Rousset, France
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/time.h>
+
+#include <asm/hardware.h>
+#include <asm/io.h>
+#include <asm/mach/time.h>
+
+#include <asm/arch/at91_pit.h>
+
+
+#define PIT_CPIV(x) ((x) & AT91_PIT_CPIV)
+#define PIT_PICNT(x) (((x) & AT91_PIT_PICNT) >> 20)
+
+/*
+ * Returns number of microseconds since last timer interrupt. Note that interrupts
+ * will have been disabled by do_gettimeofday()
+ * 'LATCH' is hwclock ticks (see CLOCK_TICK_RATE in timex.h) per jiffy.
+ * 'tick' is usecs per jiffy (linux/timex.h).
+ */
+static unsigned long at91sam926x_gettimeoffset(void)
+{
+ unsigned long elapsed;
+ unsigned long t = at91_sys_read(AT91_PIT_PIIR);
+
+ elapsed = (PIT_PICNT(t) * LATCH) + PIT_CPIV(t); /* hardware clock cycles */
+
+ return (unsigned long)(elapsed * 1000000) / LATCH;
+}
+
+/*
+ * IRQ handler for the timer.
+ */
+static irqreturn_t at91sam926x_timer_interrupt(int irq, void *dev_id)
+{
+ volatile long nr_ticks;
+
+ if (at91_sys_read(AT91_PIT_SR) & AT91_PIT_PITS) { /* This is a shared interrupt */
+ write_seqlock(&xtime_lock);
+
+ /* Get number to ticks performed before interrupt and clear PIT interrupt */
+ nr_ticks = PIT_PICNT(at91_sys_read(AT91_PIT_PIVR));
+ do {
+ timer_tick();
+ nr_ticks--;
+ } while (nr_ticks);
+
+ write_sequnlock(&xtime_lock);
+ return IRQ_HANDLED;
+ } else
+ return IRQ_NONE; /* not handled */
+}
+
+static struct irqaction at91sam926x_timer_irq = {
+ .name = "at91_tick",
+ .flags = IRQF_SHARED | IRQF_DISABLED | IRQF_TIMER,
+ .handler = at91sam926x_timer_interrupt
+};
+
+void at91sam926x_timer_reset(void)
+{
+ /* Disable timer */
+ at91_sys_write(AT91_PIT_MR, 0);
+
+ /* Clear any pending interrupts */
+ (void) at91_sys_read(AT91_PIT_PIVR);
+
+ /* Set Period Interval timer and enable its interrupt */
+ at91_sys_write(AT91_PIT_MR, (LATCH & AT91_PIT_PIV) | AT91_PIT_PITIEN | AT91_PIT_PITEN);
+}
+
+/*
+ * Set up timer interrupt.
+ */
+void __init at91sam926x_timer_init(void)
+{
+ /* Initialize and enable the timer */
+ at91sam926x_timer_reset();
+
+ /* Make IRQs happen for the system timer. */
+ setup_irq(AT91_ID_SYS, &at91sam926x_timer_irq);
+}
+
+#ifdef CONFIG_PM
+static void at91sam926x_timer_suspend(void)
+{
+ /* Disable timer */
+ at91_sys_write(AT91_PIT_MR, 0);
+}
+#else
+#define at91sam926x_timer_suspend NULL
+#endif
+
+struct sys_timer at91sam926x_timer = {
+ .init = at91sam926x_timer_init,
+ .offset = at91sam926x_gettimeoffset,
+ .suspend = at91sam926x_timer_suspend,
+ .resume = at91sam926x_timer_reset,
+};
+