NRF52_DK: use new ticker driver designed for NRF51_DK

Author: mprse

targets/TARGET_NORDIC/TARGET_NRF5x/TARGET_NRF52/common_rtc.c

@@ -0,0 +1,239 @@
+/*
+ * Copyright (c) 2013 Nordic Semiconductor ASA
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ *   1. Redistributions of source code must retain the above copyright notice, this list
+ *      of conditions and the following disclaimer.
+ *
+ *   2. Redistributions in binary form, except as embedded into a Nordic Semiconductor ASA
+ *      integrated circuit in a product or a software update for such product, must reproduce
+ *      the above copyright notice, this list of conditions and the following disclaimer in
+ *      the documentation and/or other materials provided with the distribution.
+ *
+ *   3. Neither the name of Nordic Semiconductor ASA nor the names of its contributors may be
+ *      used to endorse or promote products derived from this software without specific prior
+ *      written permission.
+ *
+ *   4. This software, with or without modification, must only be used with a
+ *      Nordic Semiconductor ASA integrated circuit.
+ *
+ *   5. Any software provided in binary or object form under this license must not be reverse
+ *      engineered, decompiled, modified and/or disassembled.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include "us_ticker_api.h"
+#include "common_rtc.h"
+#include "app_util.h"
+#include "nrf_drv_common.h"
+#include "lp_ticker_api.h"
+#include "mbed_critical.h"
+
+#if defined(NRF52_ERRATA_20)
+    #include "softdevice_handler.h"
+#endif
+
+
+//------------------------------------------------------------------------------
+// Common stuff used also by lp_ticker and rtc_api (see "common_rtc.h").
+//
+#include "app_util_platform.h"
+
+bool              m_common_rtc_enabled = false;
+uint32_t volatile m_common_rtc_overflows = 0;
+bool     volatile lp_ticker_interrupt_fire = false;
+
+__STATIC_INLINE void rtc_ovf_event_check(void)
+{
+    if (nrf_rtc_event_pending(COMMON_RTC_INSTANCE, NRF_RTC_EVENT_OVERFLOW)) {
+        nrf_rtc_event_clear(COMMON_RTC_INSTANCE, NRF_RTC_EVENT_OVERFLOW);
+        /* Don't disable this event. It shall occur periodically.
+         * It is needed for RTC. */
+
+        ++m_common_rtc_overflows;
+    }
+}
+
+#if defined(TARGET_MCU_NRF51822)
+void common_rtc_irq_handler(void)
+#else
+void COMMON_RTC_IRQ_HANDLER(void)
+#endif
+{
+    rtc_ovf_event_check();
+
+#if DEVICE_LPTICKER
+    if (nrf_rtc_event_pending(COMMON_RTC_INSTANCE, LP_TICKER_EVENT) ||
+        lp_ticker_interrupt_fire) {
+
+        if (lp_ticker_interrupt_fire) {
+            lp_ticker_interrupt_fire = false;
+        }
+
+        lp_ticker_irq_handler();
+    }
+#endif
+}
+
+/* Function for fix errata 20: RTC Register values are invalid. */
+__STATIC_INLINE void errata_20(void)
+{
+#if defined(NRF52_ERRATA_20)
+    if (!softdevice_handler_is_enabled())
+    {
+        NRF_CLOCK->EVENTS_LFCLKSTARTED = 0;
+        NRF_CLOCK->TASKS_LFCLKSTART    = 1;
+
+        while (NRF_CLOCK->EVENTS_LFCLKSTARTED == 0)
+        {
+        }
+    }
+    NRF_RTC1->TASKS_STOP = 0;
+#endif
+}
+
+void RTC1_IRQHandler(void);
+
+void common_rtc_init(void)
+{
+    if (m_common_rtc_enabled) {
+#if DEVICE_LPTICKER
+        nrf_rtc_event_clear(COMMON_RTC_INSTANCE, LP_TICKER_EVENT);
+        nrf_rtc_int_disable(COMMON_RTC_INSTANCE, LP_TICKER_INT_MASK);
+#endif
+        return;
+    }
+
+    errata_20();
+
+    nrf_rtc_task_trigger(COMMON_RTC_INSTANCE, NRF_RTC_TASK_STOP);
+
+    NVIC_SetVector(RTC1_IRQn, (uint32_t)RTC1_IRQHandler);
+
+    /* RTC is driven by the low frequency (32.768 kHz) clock, a proper request
+     * must be made to have it running.
+     * Currently this clock is started in 'SystemInit' (see "system_nrf51.c"
+     * or "system_nrf52.c", respectively).
+     */
+
+    nrf_rtc_prescaler_set(COMMON_RTC_INSTANCE, 0);
+
+    /* Clear all RTC events. */
+#if defined(TARGET_MCU_NRF51822)
+    nrf_rtc_event_clear(COMMON_RTC_INSTANCE, OS_TICK_EVENT);
+#endif
+#if DEVICE_LPTICKER
+    nrf_rtc_event_clear(COMMON_RTC_INSTANCE, LP_TICKER_EVENT);
+#endif
+    nrf_rtc_event_clear(COMMON_RTC_INSTANCE, NRF_RTC_EVENT_OVERFLOW);
+
+    /* Disable all RTC events (According to NRF_51 Reference Manual
+     * RTC events can not be used to control RTC interrupts).
+     * IRQ signal to NVIC is provided if interrupt is enabled.
+     */
+
+    nrf_rtc_event_disable(COMMON_RTC_INSTANCE, NRF_RTC_INT_OVERFLOW_MASK
+#if defined(TARGET_MCU_NRF51822)
+        | OS_TICK_INT_MASK
+#endif
+#if DEVICE_LPTICKER
+        | LP_TICKER_INT_MASK
+#endif
+     );
+
+    /* This interrupt is enabled permanently, since overflow indications are needed
+     * continuously.
+     */
+    nrf_rtc_int_enable(COMMON_RTC_INSTANCE, NRF_RTC_INT_OVERFLOW_MASK);
+
+    /* Disable LP ticker interrupt for now. */
+#if DEVICE_LPTICKER
+    nrf_rtc_int_disable(COMMON_RTC_INSTANCE, LP_TICKER_INT_MASK);
+#endif
+
+    nrf_drv_common_irq_enable(nrf_drv_get_IRQn(COMMON_RTC_INSTANCE),
+#ifdef NRF51
+        APP_IRQ_PRIORITY_LOW
+#elif defined(NRF52) || defined(NRF52840_XXAA)
+        APP_IRQ_PRIORITY_LOWEST
+#endif
+        );
+
+    nrf_rtc_task_trigger(COMMON_RTC_INSTANCE, NRF_RTC_TASK_START);
+
+    m_common_rtc_enabled = true;
+}
+
+void common_rtc_set_interrupt(uint32_t ticks_count, uint32_t cc_channel,
+                              uint32_t int_mask)
+{
+    /* Set ticks value when interrupt should be fired.
+     * Interrupt scheduling is performed in upper layers. */
+
+    core_util_critical_section_enter();
+
+    /* COMPARE occurs when a CC register is N and the COUNTER value transitions from N-1 to N.
+     * If the COUNTER is N, writing N+2 to a CC register is guaranteed to trigger a
+     * COMPARE event at N+2.
+     */
+    const uint32_t now = nrf_rtc_counter_get(COMMON_RTC_INSTANCE);
+
+    if (now == ticks_count ||
+        RTC_WRAP(now + 1) == ticks_count) {
+        ticks_count += 2;
+    }
+
+    nrf_rtc_cc_set(COMMON_RTC_INSTANCE, cc_channel, RTC_WRAP(ticks_count));
+
+    if (!nrf_rtc_int_is_enabled(COMMON_RTC_INSTANCE, int_mask)) {
+        nrf_rtc_event_clear(COMMON_RTC_INSTANCE, LP_TICKER_EVENT);
+        nrf_rtc_int_enable(COMMON_RTC_INSTANCE, int_mask);
+    }
+
+    core_util_critical_section_exit();
+}
+
+/* Since there is no SysTick on NRF51, the RTC1 channel 0 is used as an
+ * alternative source of RTOS ticks.
+ */
+#if defined(TARGET_MCU_NRF51822)
+
+#include "mbed_toolchain.h"
+
+
+#define MAX_RTC_COUNTER_VAL     ((1uL << RTC_COUNTER_BITS) - 1)
+
+#ifndef RTC1_CONFIG_FREQUENCY
+    #define RTC1_CONFIG_FREQUENCY    32678 // [Hz]
+#endif
+
+
+
+void COMMON_RTC_IRQ_HANDLER(void)
+{
+    if(!nrf_rtc_event_pending(COMMON_RTC_INSTANCE, OS_TICK_EVENT)) {
+        common_rtc_irq_handler();
+    }
+}
+
+IRQn_Type mbed_get_m0_tick_irqn()
+{
+    return SWI3_IRQn;
+}
+
+
+#endif // defined(TARGET_MCU_NRF51822)

targets/TARGET_NORDIC/TARGET_NRF5x/TARGET_NRF52/common_rtc.h

@@ -20,37 +20,29 @@
 #include "nrf_rtc.h"
 
 #define RTC_COUNTER_BITS        24u
+#define RTC_FREQ                32768u
 
 // Instance 0 is reserved for SoftDevice.
-// Instance 1 is used as a common one for us_ticker, lp_ticker and (in case
+// Instance 1 is used as a common one for lp_ticker and (in case
 // of NRF51) as an alternative tick source for RTOS.
-// ["us_ticker.c" uses hard coded addresses of the 'NRF_RTC1->EVENT_COMPARE[1]'
-//  register in inline assembly implementations of COMMON_RTC_IRQ_HANDLER,
-//  please remember to update those in case of doing changes here]
 #define COMMON_RTC_INSTANCE     NRF_RTC1
 #define COMMON_RTC_IRQ_HANDLER  RTC1_IRQHandler
-#define US_TICKER_CC_CHANNEL    0
-#define OS_TICK_CC_CHANNEL      1
-#define LP_TICKER_CC_CHANNEL    2
-
-#define US_TICKER_SW_IRQ_MASK 0x1
-#define LP_TICKER_SW_IRQ_MASK 0x2
+#define OS_TICK_CC_CHANNEL      0
+#define LP_TICKER_CC_CHANNEL    1
 
 #define COMMON_RTC_EVENT_COMPARE(channel) \
     CONCAT_2(NRF_RTC_EVENT_COMPARE_, channel)
 #define COMMON_RTC_INT_COMPARE_MASK(channel) \
     CONCAT_3(NRF_RTC_INT_COMPARE, channel, _MASK)
 
-#define US_TICKER_EVENT     COMMON_RTC_EVENT_COMPARE(US_TICKER_CC_CHANNEL)
-#define US_TICKER_INT_MASK  COMMON_RTC_INT_COMPARE_MASK(US_TICKER_CC_CHANNEL)
 #define OS_TICK_EVENT       COMMON_RTC_EVENT_COMPARE(OS_TICK_CC_CHANNEL)
 #define OS_TICK_INT_MASK    COMMON_RTC_INT_COMPARE_MASK(OS_TICK_CC_CHANNEL)
 #define LP_TICKER_EVENT     COMMON_RTC_EVENT_COMPARE(LP_TICKER_CC_CHANNEL)
 #define LP_TICKER_INT_MASK  COMMON_RTC_INT_COMPARE_MASK(LP_TICKER_CC_CHANNEL)
 
 extern bool              m_common_rtc_enabled;
 extern uint32_t volatile m_common_rtc_overflows;
-extern uint8_t volatile m_common_sw_irq_flag; 
+extern bool volatile     lp_ticker_interrupt_fire;
 
 void     common_rtc_init(void);
 uint32_t common_rtc_32bit_ticks_get(void);

targets/TARGET_NORDIC/TARGET_NRF5x/TARGET_NRF52/lp_ticker.c

@@ -14,20 +14,35 @@
  * limitations under the License.
  */
 #include "lp_ticker_api.h"
+#include "common_rtc.h"
+#include "platform/mbed_critical.h"
 
-#if DEVICE_LOWPOWERTIMER
+#if DEVICE_LPTICKER
 
-#include "common_rtc.h"
-#include "mbed_critical.h"
+/* LP ticker is driven by 32kHz clock and counter length is 24 bits. */
+const ticker_info_t* lp_ticker_get_info()
+{
+    static const ticker_info_t info = {
+        RTC_FREQ,
+        RTC_COUNTER_BITS
+    };
+    return &info;
+}
 
 void lp_ticker_init(void)
 {
     common_rtc_init();
 }
 
+void lp_ticker_free(void)
+{
+    // A common counter is used for RTC, lp_ticker and us_ticker, so it can't be
+    // disabled here, but this does not cause any extra cost.
+}
+
 uint32_t lp_ticker_read()
 {
-    return (uint32_t)common_rtc_64bit_us_get();
+    return nrf_rtc_counter_get(COMMON_RTC_INSTANCE);
 }
 
 void lp_ticker_set_interrupt(timestamp_t timestamp)
@@ -39,19 +54,22 @@ void lp_ticker_set_interrupt(timestamp_t timestamp)
 void lp_ticker_fire_interrupt(void)
 {
     core_util_critical_section_enter();
-    m_common_sw_irq_flag |= LP_TICKER_SW_IRQ_MASK;
+
+    lp_ticker_interrupt_fire = true;
+
     NVIC_SetPendingIRQ(RTC1_IRQn);
+
     core_util_critical_section_exit();
 }
 
 void lp_ticker_disable_interrupt(void)
 {
-    nrf_rtc_event_disable(COMMON_RTC_INSTANCE, LP_TICKER_INT_MASK);
+    nrf_rtc_int_disable(COMMON_RTC_INSTANCE, LP_TICKER_INT_MASK);
 }
 
 void lp_ticker_clear_interrupt(void)
 {
     nrf_rtc_event_clear(COMMON_RTC_INSTANCE, LP_TICKER_EVENT);
 }
 
-#endif // DEVICE_LOWPOWERTIMER
+#endif // DEVICE_LPTICKER