drivers: timer: nRF SoC Series RTC system clock implementation
The nRF5x series SoCs do not implement systick, hence we disable
CORTEX_M_SYSTICK.
Instead, use nRF SoC Series NRF_RTC1 for system clock interfaces.
The kernel system clock interface is implemented using the low
power real time counter NRF_RTC1. NRF_RTC0 is used by the BLE
controller.
In addition, cleanup nRF5x series defconfig to be consistent.
Jira: ZEP-742
Jira: ZEP-1308
Jira: ZEP-1315
Change-id: I0f6cc1836fe0820a65f2cbb02cf5ae7e9eb92e1d
Signed-off-by: Vinayak Chettimada <vinayak.kariappa.chettimada@nordicsemi.no>
Signed-off-by: Carles Cufi <carles.cufi@nordicsemi.no>
Signed-off-by: Anas Nashif <anas.nashif@intel.com>
diff --git a/drivers/timer/nrf_rtc_timer.c b/drivers/timer/nrf_rtc_timer.c
new file mode 100644
index 0000000..9557cad
--- /dev/null
+++ b/drivers/timer/nrf_rtc_timer.c
@@ -0,0 +1,125 @@
+/*
+ * Copyright (c) 2016 Nordic Semiconductor ASA
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <soc.h>
+#include <clock_control.h>
+#include <system_timer.h>
+#include <drivers/clock_control/nrf5_clock_control.h>
+
+#define RTC_TICKS ((uint32_t)(((((uint64_t)1000000UL / \
+ CONFIG_SYS_CLOCK_TICKS_PER_SEC) * \
+ 1000000000UL) / 30517578125UL)) & 0x00FFFFFF)
+
+extern int64_t _sys_clock_tick_count;
+
+#ifdef CONFIG_TICKLESS_IDLE
+extern int32_t _sys_idle_elapsed_ticks;
+
+void _timer_idle_enter(int32_t ticks)
+{
+ /* restrict ticks to max supported by RTC */
+ if ((ticks < 0) || (ticks > (0x00FFFFFF / RTC_TICKS))) {
+ ticks = 0x00FFFFFF / RTC_TICKS;
+ }
+
+ /* setup next RTC compare event by ticks amount */
+ NRF_RTC1->CC[0] = ((_sys_clock_tick_count + ticks) * RTC_TICKS) &
+ 0x00FFFFFF;
+
+ /* TODO: check if CC is set to stale value */
+}
+
+void _timer_idle_exit(void)
+{
+ uint32_t elapsed_ticks;
+
+ /* update with elapsed ticks from h/w */
+ elapsed_ticks = ((NRF_RTC1->COUNTER -
+ (_sys_clock_tick_count * RTC_TICKS)) /
+ RTC_TICKS) & 0x00FFFFFF;
+
+ /* setup next RTC compare event by 1 tick */
+ NRF_RTC1->CC[0] = ((_sys_clock_tick_count + elapsed_ticks + 1) *
+ RTC_TICKS) & 0x00FFFFFF;
+
+ /* TODO: check if CC is set to stale value */
+}
+#endif /* CONFIG_TICKLESS_IDLE */
+
+static void rtc1_nrf5_isr(void *arg)
+{
+ ARG_UNUSED(arg);
+
+ if (NRF_RTC1->EVENTS_COMPARE[0]) {
+ NRF_RTC1->EVENTS_COMPARE[0] = 0;
+
+#ifdef CONFIG_TICKLESS_IDLE
+ /* update with elapsed ticks from h/w */
+ _sys_idle_elapsed_ticks = ((NRF_RTC1->COUNTER -
+ (_sys_clock_tick_count *
+ RTC_TICKS)) / RTC_TICKS) &
+ 0x00FFFFFF;
+#endif
+
+ /* setup next RTC compare event */
+ NRF_RTC1->CC[0] = ((_sys_clock_tick_count +
+ _sys_idle_elapsed_ticks + 1) * RTC_TICKS)
+ & 0x00FFFFFF;
+
+ /* TODO: check if CC is set to stale value */
+
+ _sys_clock_tick_announce();
+ }
+}
+
+int _sys_clock_driver_init(struct device *device)
+{
+ struct device *clock;
+ int retval;
+
+ ARG_UNUSED(device);
+
+ clock = device_get_binding(CONFIG_CLOCK_CONTROL_NRF5_K32SRC_DRV_NAME);
+ if (!clock) {
+ return -1;
+ }
+
+ clock_control_on(clock, (void *)CLOCK_CONTROL_NRF5_K32SRC);
+
+ /* TODO: replace with counter driver to access RTC */
+ NRF_RTC1->PRESCALER = 0;
+ NRF_RTC1->CC[0] = RTC_TICKS;
+ NRF_RTC1->EVTENSET = RTC_EVTENSET_COMPARE0_Msk;
+ NRF_RTC1->INTENSET = RTC_INTENSET_COMPARE0_Msk;
+
+ IRQ_CONNECT(NRF5_IRQ_RTC1_IRQn, 1, rtc1_nrf5_isr, 0, 0);
+ irq_enable(NRF5_IRQ_RTC1_IRQn);
+
+ NRF_RTC1->TASKS_START = 1;
+
+ return retval;
+}
+
+uint32_t sys_cycle_get_32(void)
+{
+ uint32_t elapsed_cycles;
+
+ elapsed_cycles = (NRF_RTC1->COUNTER -
+ (_sys_clock_tick_count * RTC_TICKS)) & 0x00FFFFFF;
+
+ return (_sys_clock_tick_count * sys_clock_hw_cycles_per_tick) +
+ elapsed_cycles;
+}
