Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / arch / xtensa / kernel / time.c

diff --git a/kernel/arch/xtensa/kernel/time.c b/kernel/arch/xtensa/kernel/time.c
new file mode 100644 (file)
index 0000000..2a1823d
--- /dev/null
+++ b/kernel/arch/xtensa/kernel/time.c
@@ -0,0 +1,181 @@
+/*
+ * arch/xtensa/kernel/time.c
+ *
+ * Timer and clock support.
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2005 Tensilica Inc.
+ *
+ * Chris Zankel <chris@zankel.net>
+ */
+
+#include <linux/errno.h>
+#include <linux/sched.h>
+#include <linux/time.h>
+#include <linux/clocksource.h>
+#include <linux/clockchips.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/irq.h>
+#include <linux/profile.h>
+#include <linux/delay.h>
+#include <linux/irqdomain.h>
+#include <linux/sched_clock.h>
+
+#include <asm/timex.h>
+#include <asm/platform.h>
+
+unsigned long ccount_freq;             /* ccount Hz */
+EXPORT_SYMBOL(ccount_freq);
+
+static cycle_t ccount_read(struct clocksource *cs)
+{
+       return (cycle_t)get_ccount();
+}
+
+static u64 notrace ccount_sched_clock_read(void)
+{
+       return get_ccount();
+}
+
+static struct clocksource ccount_clocksource = {
+       .name = "ccount",
+       .rating = 200,
+       .read = ccount_read,
+       .mask = CLOCKSOURCE_MASK(32),
+       .flags = CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+static int ccount_timer_set_next_event(unsigned long delta,
+               struct clock_event_device *dev);
+static void ccount_timer_set_mode(enum clock_event_mode mode,
+               struct clock_event_device *evt);
+struct ccount_timer {
+       struct clock_event_device evt;
+       int irq_enabled;
+       char name[24];
+};
+static DEFINE_PER_CPU(struct ccount_timer, ccount_timer);
+
+static int ccount_timer_set_next_event(unsigned long delta,
+               struct clock_event_device *dev)
+{
+       unsigned long flags, next;
+       int ret = 0;
+
+       local_irq_save(flags);
+       next = get_ccount() + delta;
+       set_linux_timer(next);
+       if (next - get_ccount() > delta)
+               ret = -ETIME;
+       local_irq_restore(flags);
+
+       return ret;
+}
+
+static void ccount_timer_set_mode(enum clock_event_mode mode,
+               struct clock_event_device *evt)
+{
+       struct ccount_timer *timer =
+               container_of(evt, struct ccount_timer, evt);
+
+       /*
+        * There is no way to disable the timer interrupt at the device level,
+        * only at the intenable register itself. Since enable_irq/disable_irq
+        * calls are nested, we need to make sure that these calls are
+        * balanced.
+        */
+       switch (mode) {
+       case CLOCK_EVT_MODE_SHUTDOWN:
+       case CLOCK_EVT_MODE_UNUSED:
+               if (timer->irq_enabled) {
+                       disable_irq(evt->irq);
+                       timer->irq_enabled = 0;
+               }
+               break;
+       case CLOCK_EVT_MODE_RESUME:
+       case CLOCK_EVT_MODE_ONESHOT:
+               if (!timer->irq_enabled) {
+                       enable_irq(evt->irq);
+                       timer->irq_enabled = 1;
+               }
+       default:
+               break;
+       }
+}
+
+static irqreturn_t timer_interrupt(int irq, void *dev_id);
+static struct irqaction timer_irqaction = {
+       .handler =      timer_interrupt,
+       .flags =        IRQF_TIMER,
+       .name =         "timer",
+};
+
+void local_timer_setup(unsigned cpu)
+{
+       struct ccount_timer *timer = &per_cpu(ccount_timer, cpu);
+       struct clock_event_device *clockevent = &timer->evt;
+
+       timer->irq_enabled = 1;
+       clockevent->name = timer->name;
+       snprintf(timer->name, sizeof(timer->name), "ccount_clockevent_%u", cpu);
+       clockevent->features = CLOCK_EVT_FEAT_ONESHOT;
+       clockevent->rating = 300;
+       clockevent->set_next_event = ccount_timer_set_next_event;
+       clockevent->set_mode = ccount_timer_set_mode;
+       clockevent->cpumask = cpumask_of(cpu);
+       clockevent->irq = irq_create_mapping(NULL, LINUX_TIMER_INT);
+       if (WARN(!clockevent->irq, "error: can't map timer irq"))
+               return;
+       clockevents_config_and_register(clockevent, ccount_freq,
+                                       0xf, 0xffffffff);
+}
+
+void __init time_init(void)
+{
+#ifdef CONFIG_XTENSA_CALIBRATE_CCOUNT
+       printk("Calibrating CPU frequency ");
+       platform_calibrate_ccount();
+       printk("%d.%02d MHz\n", (int)ccount_freq/1000000,
+                       (int)(ccount_freq/10000)%100);
+#else
+       ccount_freq = CONFIG_XTENSA_CPU_CLOCK*1000000UL;
+#endif
+       clocksource_register_hz(&ccount_clocksource, ccount_freq);
+       local_timer_setup(0);
+       setup_irq(this_cpu_ptr(&ccount_timer)->evt.irq, &timer_irqaction);
+       sched_clock_register(ccount_sched_clock_read, 32, ccount_freq);
+       clocksource_of_init();
+}
+
+/*
+ * The timer interrupt is called HZ times per second.
+ */
+
+irqreturn_t timer_interrupt(int irq, void *dev_id)
+{
+       struct clock_event_device *evt = &this_cpu_ptr(&ccount_timer)->evt;
+
+       set_linux_timer(get_linux_timer());
+       evt->event_handler(evt);
+
+       /* Allow platform to do something useful (Wdog). */
+       platform_heartbeat();
+
+       return IRQ_HANDLED;
+}
+
+#ifndef CONFIG_GENERIC_CALIBRATE_DELAY
+void calibrate_delay(void)
+{
+       loops_per_jiffy = ccount_freq / HZ;
+       printk("Calibrating delay loop (skipped)... "
+              "%lu.%02lu BogoMIPS preset\n",
+              loops_per_jiffy/(1000000/HZ),
+              (loops_per_jiffy/(10000/HZ)) % 100);
+}
+#endif