1 files changed, 104 insertions, 0 deletions
diff --git a/platform/nrf52xxx/timer.c b/platform/nrf52xxx/timer.c
new file mode 100644
index 00000000..5603a294
--- /dev/null
+++ b/platform/nrf52xxx/timer.c
@@ -0,0 +1,104 @@
+/*
+ * Copyright (c) 2015 Eric Holland
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files
+ * (the "Software"), to deal in the Software without restriction,
+ * including without limitation the rights to use, copy, modify, merge,
+ * publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+#include <err.h>
+#include <debug.h>
+#include <trace.h>
+#include <arch/arm/cm.h>
+#include <platform.h>
+#include <platform/nrf52.h>
+#include <platform/system_nrf52.h>
+#include <platform/timer.h>
+#include <sys/types.h>
+
+
+static volatile uint64_t ticks;
+static uint32_t tick_rate = 0;
+static uint32_t tick_rate_mhz = 0;
+static lk_time_t tick_interval_ms;
+
+static platform_timer_callback cb;
+static void *cb_args;
+
+typedef enum handler_return (*platform_timer_callback)(void *arg, lk_time_t now);
+
+status_t platform_set_periodic_timer(platform_timer_callback callback, void *arg, lk_time_t interval)
+{
+
+    cb = callback;
+    cb_args = arg;
+
+    tick_interval_ms = interval;
+
+    uint32_t ticks = tick_rate / ( 1000 / interval );
+
+    NRF_CLOCK->LFCLKSRC =  CLOCK_LFCLKSRC_SRC_Xtal << CLOCK_LFCLKSRC_SRC_Pos;
+    NRF_CLOCK->TASKS_LFCLKSTART = 1;
+
+    NRF_RTC1->PRESCALER = ticks;
+    NRF_RTC1->INTENSET  = RTC_INTENSET_TICK_Enabled << RTC_INTENSET_TICK_Pos;
+
+    NRF_RTC1->EVENTS_TICK = 0;
+    NRF_RTC1->TASKS_START = 1;
+    NVIC_EnableIRQ(RTC1_IRQn);
+
+    return NO_ERROR;
+}
+
+lk_time_t current_time(void)
+{
+    uint64_t t;
+
+    do {
+        t = ticks;
+    } while (ticks != t);
+
+    return t * tick_interval_ms;
+}
+
+lk_bigtime_t current_time_hires(void)
+{
+    return current_time() * 1000;
+}
+
+void nrf52_RTC1_IRQ(void)
+{
+    ticks++;
+    arm_cm_irq_entry();
+
+    NRF_RTC1->EVENTS_TICK = 0;
+
+    bool resched = false;
+    if (cb) {
+        lk_time_t now = current_time();
+        if (cb(cb_args, now) == INT_RESCHEDULE)
+            resched = true;
+    }
+    arm_cm_irq_exit(resched);
+}
+
+void arm_cm_systick_init(uint32_t mhz)
+{
+    tick_rate = mhz;
+    tick_rate_mhz = mhz / 1000000;
+}
+