From: Octavian Purdila <tavi.purdila@xxxxxxxxx>
Clockevent driver based on host timer operations and clocksource
driver and udelay support based on host time operations.
Cc: Michael Zimmermann <sigmaepsilon92@xxxxxxxxx>
Signed-off-by: Hajime Tazaki <thehajime@xxxxxxxxx>
Signed-off-by: Octavian Purdila <tavi.purdila@xxxxxxxxx>
---
arch/um/lkl/include/uapi/asm/host_ops.h | 13 +++
arch/um/lkl/kernel/time.c | 145 ++++++++++++++++++++++++
2 files changed, 158 insertions(+)
create mode 100644 arch/um/lkl/kernel/time.c
diff --git a/arch/um/lkl/include/uapi/asm/host_ops.h b/arch/um/lkl/include/uapi/asm/host_ops.h
index 1c839d7139f8..c9f77dd7fbe7 100644
--- a/arch/um/lkl/include/uapi/asm/host_ops.h
+++ b/arch/um/lkl/include/uapi/asm/host_ops.h
@@ -48,6 +48,13 @@ struct lkl_jmp_buf {
* @mem_alloc - allocate memory
* @mem_free - free memory
*
+ * @timer_create - allocate a host timer that runs fn(arg) when the timer
+ * fires.
+ * @timer_free - disarms and free the timer
+ * @timer_set_oneshot - arm the timer to fire once, after delta ns.
+ * @timer_set_periodic - arm the timer to fire periodically, with a period of
+ * delta ns.
+ *
* @gettid - returns the host thread id of the caller, which need not
* be the same as the handle returned by thread_create
*
@@ -88,6 +95,12 @@ struct lkl_host_operations {
void *(*mem_alloc)(unsigned long mem);
void (*mem_free)(void *mem);
+ unsigned long long (*time)(void);
+
+ void *(*timer_alloc)(void (*fn)(void *), void *arg);
+ int (*timer_set_oneshot)(void *timer, unsigned long delta);
+ void (*timer_free)(void *timer);
+
long (*gettid)(void);
void (*jmp_buf_set)(struct lkl_jmp_buf *jmpb, void (*f)(void));
diff --git a/arch/um/lkl/kernel/time.c b/arch/um/lkl/kernel/time.c
new file mode 100644
index 000000000000..b8320e1bfa53
--- /dev/null
+++ b/arch/um/lkl/kernel/time.c
@@ -0,0 +1,145 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/clocksource.h>
+#include <linux/clockchips.h>
+#include <linux/jiffies.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <asm/host_ops.h>
+
+static unsigned long long boot_time;
+
+void __ndelay(unsigned long nsecs)
+{
+ unsigned long long start = lkl_ops->time();
+
+ while (lkl_ops->time() < start + nsecs)
+ ;
+}
+
+void __udelay(unsigned long usecs)
+{
+ __ndelay(usecs * NSEC_PER_USEC);
+}
+
+void __const_udelay(unsigned long xloops)
+{
+ __udelay(xloops / 0x10c7ul);
+}
+
+void calibrate_delay(void)
+{
+}
+
+void read_persistent_clock(struct timespec *ts)
+{
+ *ts = ns_to_timespec(lkl_ops->time());
+}
+
+/*
+ * Scheduler clock - returns current time in nanosec units.
+ *
+ */
+unsigned long long sched_clock(void)
+{
+ if (!boot_time)
+ return 0;
+
+ return lkl_ops->time() - boot_time;
+}
+
+static u64 clock_read(struct clocksource *cs)
+{
+ return lkl_ops->time();
+}
+
+static struct clocksource clocksource = {
+ .name = "lkl",
+ .rating = 499,
+ .read = clock_read,
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
+ .mask = CLOCKSOURCE_MASK(64),
+};
+
+static void *timer;
+
+static int timer_irq;
+
+static void timer_fn(void *arg)
+{
+ lkl_trigger_irq(timer_irq);
+}
+
+static int clockevent_set_state_shutdown(struct clock_event_device *evt)
+{
+ if (timer) {
+ lkl_ops->timer_free(timer);
+ timer = NULL;
+ }
+
+ return 0;
+}
+
+static int clockevent_set_state_oneshot(struct clock_event_device *evt)
+{
+ timer = lkl_ops->timer_alloc(timer_fn, NULL);
+ if (!timer)
+ return -ENOMEM;
+
+ return 0;
+}
+
+static irqreturn_t timer_irq_handler(int irq, void *dev_id)
+{
+ struct clock_event_device *dev = (struct clock_event_device *)dev_id;
+
+ dev->event_handler(dev);
+
+ return IRQ_HANDLED;
+}
+
+static int clockevent_next_event(unsigned long ns,
+ struct clock_event_device *evt)
+{
+ return lkl_ops->timer_set_oneshot(timer, ns);
+}
+
+static struct clock_event_device clockevent = {
+ .name = "lkl",
+ .features = CLOCK_EVT_FEAT_ONESHOT,
+ .set_state_oneshot = clockevent_set_state_oneshot,
+ .set_next_event = clockevent_next_event,
+ .set_state_shutdown = clockevent_set_state_shutdown,
+};
+
+static struct irqaction irq0 = {
+ .handler = timer_irq_handler,
+ .flags = IRQF_NOBALANCING | IRQF_TIMER,
+ .dev_id = &clockevent,
+ .name = "timer"
+};
+
+void __init time_init(void)
+{
+ int ret;
+
+ if (!lkl_ops->timer_alloc || !lkl_ops->timer_free ||
+ !lkl_ops->timer_set_oneshot || !lkl_ops->time) {
+ pr_err("lkl: no time or timer support provided by host\n");
+ return;
+ }
+
+ timer_irq = lkl_get_free_irq("timer");
+ setup_irq(timer_irq, &irq0);
+
+ ret = clocksource_register_khz(&clocksource, 1000000);
+ if (ret)
+ pr_err("lkl: unable to register clocksource\n");
+
+ clockevents_config_and_register(&clockevent, NSEC_PER_SEC, 1,
+ ULONG_MAX);
+
+ boot_time = lkl_ops->time();
+ pr_info("lkl: time and timers initialized (irq%d)\n", timer_irq);
+}
--
2.21.0 (Apple Git-122.2)
