Import Mbed OS hard-float snapshot

targets/TARGET_ARM_SSG/TARGET_CM3DS_MPS2/lp_ticker.c

@@ -0,0 +1,108 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2017-2018 Arm Limited
+ *
+ * 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.
+ */
+
+/**
+ * Supports the Low Power Ticker for mbed by implementing \ref lp_ticker_api.h,
+ * using both timers in a CMSDK Dual Timer \ref dualtimer_cmsdk_dev_t.
+ */
+
+#include "dualtimer_cmsdk_drv.h"
+#include "lp_ticker_api.h"
+#include "platform_devices.h"
+
+static uint32_t last_read = 0;
+
+/* Initializes both timers in the Dualtimer:
+ *      -Timer1 as the free running timer
+ *      -Timer2 as the interval timer
+ * Both timers are set:
+ *      -32 bit size
+ *      -256 Clk divisor
+ *      -Maximum reload value
+ */
+void lp_ticker_init(void)
+{
+    dualtimer_cmsdk_init(&LP_TIMER_DEV);
+    dualtimer_cmsdk_set_size_both_timers(&LP_TIMER_DEV,
+                                         DUALTIMER_CMSDK_SIZE_32BIT);
+    dualtimer_cmsdk_set_prescale_both_timers(&LP_TIMER_DEV,
+                                        DUALTIMER_CMSDK_CLOCK_DIV256);
+    dualtimer_cmsdk_disable_both_timers(&LP_TIMER_DEV);
+    dualtimer_cmsdk_set_reload_both_timers(&LP_TIMER_DEV,
+                                 TIMER_CMSDK_MAX_RELOAD);
+    dualtimer_cmsdk_reset_both_timers(&LP_TIMER_DEV);
+    NVIC_EnableIRQ(LP_INTERVAL_IRQ);
+    dualtimer_cmsdk_enable_both_timers(&LP_TIMER_DEV);
+}
+
+void lp_ticker_free(void)
+{
+    dualtimer_cmsdk_free(&LP_TIMER_DEV);
+}
+
+uint32_t lp_ticker_read()
+{
+    uint32_t tick = dualtimer_cmsdk_get_elapsed_value_timer1(&LP_TIMER_DEV);
+    last_read = tick >> LP_REPORTED_SHIFT;
+    return last_read;
+}
+
+void lp_ticker_set_interrupt(timestamp_t timestamp)
+{
+    uint32_t reload = (timestamp - last_read) << LP_REPORTED_SHIFT;
+    dualtimer_cmsdk_disable_timer2(&LP_TIMER_DEV);
+    dualtimer_cmsdk_set_reload_timer2(&LP_TIMER_DEV, reload);
+    dualtimer_cmsdk_reset_timer2(&LP_TIMER_DEV);
+    dualtimer_cmsdk_enable_interrupt_timer2(&LP_TIMER_DEV);
+    dualtimer_cmsdk_enable_timer2(&LP_TIMER_DEV);
+}
+
+void lp_ticker_disable_interrupt(void)
+{
+    dualtimer_cmsdk_disable_interrupt_timer2(&LP_TIMER_DEV);
+}
+
+void lp_ticker_clear_interrupt(void)
+{
+    dualtimer_cmsdk_clear_interrupt_timer2(&LP_TIMER_DEV);
+}
+
+void lp_ticker_fire_interrupt(void)
+{
+    NVIC_SetPendingIRQ(LP_INTERVAL_IRQ);
+}
+
+const ticker_info_t* lp_ticker_get_info()
+{
+    static const ticker_info_t info = {
+        LP_REPORTED_FREQ_HZ,
+        LP_REPORTED_BITS
+    };
+    return &info;
+}
+
+#ifndef lp_interval_irq_handler
+#error "lp_interval_irq_handler should be defined, check device_cfg.h!"
+#endif
+/* According to mbed's specification, the free running timer shouldn't fire
+ * interrupt, since the upper layer polls that and handles the overflow,
+ * by cumulating the read values.
+ */
+void lp_interval_irq_handler(void)
+{
+    lp_ticker_disable_interrupt();
+    lp_ticker_irq_handler();
+}