aboutsummaryrefslogtreecommitdiff
path: root/arch/mn10300/kernel/time.c
diff options
context:
space:
mode:
authorDavid Howells <dhowells@redhat.com>2008-02-08 04:19:31 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2008-02-08 09:22:30 -0800
commitb920de1b77b72ca9432ac3f97edb26541e65e5dd (patch)
tree40fa9be1470e929c47927dea7eddf184c0204229 /arch/mn10300/kernel/time.c
parentef3d534754f31fed9c3b976fee1ece1b3bc38282 (diff)
downloadlinux-linaro-stable-b920de1b77b72ca9432ac3f97edb26541e65e5dd.tar.gz
mn10300: add the MN10300/AM33 architecture to the kernel
Add architecture support for the MN10300/AM33 CPUs produced by MEI to the kernel. This patch also adds board support for the ASB2303 with the ASB2308 daughter board, and the ASB2305. The only processor supported is the MN103E010, which is an AM33v2 core plus on-chip devices. [akpm@linux-foundation.org: nuke cvs control strings] Signed-off-by: Masakazu Urade <urade.masakazu@jp.panasonic.com> Signed-off-by: Koichi Yasutake <yasutake.koichi@jp.panasonic.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/mn10300/kernel/time.c')
-rw-r--r--arch/mn10300/kernel/time.c129
1 files changed, 129 insertions, 0 deletions
diff --git a/arch/mn10300/kernel/time.c b/arch/mn10300/kernel/time.c
new file mode 100644
index 000000000000..ff492e3b3457
--- /dev/null
+++ b/arch/mn10300/kernel/time.c
@@ -0,0 +1,129 @@
+/* MN10300 Low level time management
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ * - Derived from arch/i386/kernel/time.c
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/interrupt.h>
+#include <linux/time.h>
+#include <linux/init.h>
+#include <linux/smp.h>
+#include <linux/profile.h>
+#include <asm/irq.h>
+#include <asm/div64.h>
+#include <asm/processor.h>
+#include <asm/intctl-regs.h>
+#include <asm/rtc.h>
+
+#ifdef CONFIG_MN10300_RTC
+unsigned long mn10300_ioclk; /* system I/O clock frequency */
+unsigned long mn10300_iobclk; /* system I/O clock frequency */
+unsigned long mn10300_tsc_per_HZ; /* number of ioclks per jiffy */
+#endif /* CONFIG_MN10300_RTC */
+
+static unsigned long mn10300_last_tsc; /* time-stamp counter at last time
+ * interrupt occurred */
+
+static irqreturn_t timer_interrupt(int irq, void *dev_id);
+
+static struct irqaction timer_irq = {
+ .handler = timer_interrupt,
+ .flags = IRQF_DISABLED | IRQF_SHARED | IRQF_TIMER,
+ .mask = CPU_MASK_NONE,
+ .name = "timer",
+};
+
+/*
+ * scheduler clock - returns current time in nanosec units.
+ */
+unsigned long long sched_clock(void)
+{
+ union {
+ unsigned long long l;
+ u32 w[2];
+ } quot;
+
+ quot.w[0] = mn10300_last_tsc - get_cycles();
+ quot.w[1] = 1000000000;
+
+ asm("mulu %2,%3,%0,%1"
+ : "=r"(quot.w[1]), "=r"(quot.w[0])
+ : "0"(quot.w[1]), "1"(quot.w[0])
+ : "cc");
+
+ do_div(quot.l, MN10300_TSCCLK);
+
+ return quot.l;
+}
+
+/*
+ * advance the kernel's time keeping clocks (xtime and jiffies)
+ * - we use Timer 0 & 1 cascaded as a clock to nudge us the next time
+ * there's a need to update
+ */
+static irqreturn_t timer_interrupt(int irq, void *dev_id)
+{
+ unsigned tsc, elapse;
+
+ write_seqlock(&xtime_lock);
+
+ while (tsc = get_cycles(),
+ elapse = mn10300_last_tsc - tsc, /* time elapsed since last
+ * tick */
+ elapse > MN10300_TSC_PER_HZ
+ ) {
+ mn10300_last_tsc -= MN10300_TSC_PER_HZ;
+
+ /* advance the kernel's time tracking system */
+ profile_tick(CPU_PROFILING);
+ do_timer(1);
+ update_process_times(user_mode(get_irq_regs()));
+ check_rtc_time();
+ }
+
+ write_sequnlock(&xtime_lock);
+ return IRQ_HANDLED;
+}
+
+/*
+ * initialise the various timers used by the main part of the kernel
+ */
+void __init time_init(void)
+{
+ /* we need the prescalar running to be able to use IOCLK/8
+ * - IOCLK runs at 1/4 (ST5 open) or 1/8 (ST5 closed) internal CPU clock
+ * - IOCLK runs at Fosc rate (crystal speed)
+ */
+ TMPSCNT |= TMPSCNT_ENABLE;
+
+ startup_timestamp_counter();
+
+ printk(KERN_INFO
+ "timestamp counter I/O clock running at %lu.%02lu"
+ " (calibrated against RTC)\n",
+ MN10300_TSCCLK / 1000000, (MN10300_TSCCLK / 10000) % 100);
+
+ xtime.tv_sec = get_initial_rtc_time();
+ xtime.tv_nsec = 0;
+
+ mn10300_last_tsc = TMTSCBC;
+
+ /* use timer 0 & 1 cascaded to tick at as close to HZ as possible */
+ setup_irq(TMJCIRQ, &timer_irq);
+
+ set_intr_level(TMJCIRQ, TMJCICR_LEVEL);
+
+ startup_jiffies_counter();
+
+#ifdef CONFIG_MN10300_WD_TIMER
+ /* start the watchdog timer */
+ watchdog_go();
+#endif
+}