Import Mbed OS hard-float snapshot

targets/TARGET_Silicon_Labs/TARGET_EFM32/us_ticker.c

@@ -0,0 +1,131 @@
+/***************************************************************************//**
+ * @file us_ticker.c
+ *******************************************************************************
+ * @section License
+ * <b>(C) Copyright 2016 Silicon Labs, http://www.silabs.com</b>
+ *******************************************************************************
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * 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 <stddef.h>
+#include "us_ticker_api.h"
+#include "device.h"
+#include "mbed_assert.h"
+#include "em_cmu.h"
+#include "em_timer.h"
+#include "clocking.h"
+
+#define TICKER_FREQUENCY ((REFERENCE_FREQUENCY > 24000000) ? REFERENCE_FREQUENCY / 16 : REFERENCE_FREQUENCY / 8)
+
+const ticker_info_t* us_ticker_get_info(void)
+{
+    static const ticker_info_t info = {
+        TICKER_FREQUENCY,
+        16
+    };
+    return &info;
+}
+
+static bool us_ticker_inited = false;            // Is ticker initialized yet
+
+void us_ticker_init(void)
+{
+    if (us_ticker_inited) {
+        /* calling init again should cancel current interrupt */
+        us_ticker_disable_interrupt();
+        return;
+    }
+    us_ticker_inited = true;
+
+    /* Enable clock for TIMERs */
+    CMU_ClockEnable(US_TICKER_TIMER_CLOCK, true);
+
+    if (REFERENCE_FREQUENCY > 24000000) {
+        US_TICKER_TIMER->CTRL = (US_TICKER_TIMER->CTRL & ~_TIMER_CTRL_PRESC_MASK) | (4 << _TIMER_CTRL_PRESC_SHIFT);
+    } else {
+        US_TICKER_TIMER->CTRL = (US_TICKER_TIMER->CTRL & ~_TIMER_CTRL_PRESC_MASK) | (3 << _TIMER_CTRL_PRESC_SHIFT);
+    }
+
+    /* Clear TIMER counter value */
+    TIMER_CounterSet(US_TICKER_TIMER, 0);
+
+    /* Start TIMER */
+    TIMER_Enable(US_TICKER_TIMER, true);
+
+    /* Select Compare Channel parameters */
+    TIMER_InitCC_TypeDef timerCCInit = TIMER_INITCC_DEFAULT;
+    timerCCInit.mode = timerCCModeCompare;
+
+    /* Configure Compare Channel 0 */
+    TIMER_InitCC(US_TICKER_TIMER, 0, &timerCCInit);
+
+    /* Enable interrupt vector in NVIC */
+    TIMER_IntClear(US_TICKER_TIMER, TIMER_IEN_CC0);
+    NVIC_SetVector(US_TICKER_TIMER_IRQ, (uint32_t) us_ticker_irq_handler);
+    NVIC_EnableIRQ(US_TICKER_TIMER_IRQ);
+}
+
+void us_ticker_free(void)
+{
+    if (us_ticker_inited) {
+        us_ticker_disable_interrupt();
+        NVIC_DisableIRQ(US_TICKER_TIMER_IRQ);
+
+        TIMER_Enable(US_TICKER_TIMER, false);
+
+        CMU_ClockEnable(US_TICKER_TIMER_CLOCK, false);
+
+        us_ticker_inited = false;
+    }
+}
+
+uint32_t us_ticker_read()
+{
+    if (!us_ticker_inited) {
+        us_ticker_init();
+    }
+
+    return US_TICKER_TIMER->CNT;
+}
+
+void us_ticker_set_interrupt(timestamp_t timestamp)
+{
+    TIMER_IntDisable(US_TICKER_TIMER, TIMER_IEN_CC0);
+
+    TIMER_IntClear(US_TICKER_TIMER, TIMER_IEN_CC0);
+
+    TIMER_CompareSet(US_TICKER_TIMER, 0, timestamp);
+
+    TIMER_IntEnable(US_TICKER_TIMER, TIMER_IEN_CC0);
+}
+
+void us_ticker_fire_interrupt(void)
+{
+    NVIC_SetPendingIRQ(US_TICKER_TIMER_IRQ);
+}
+
+void us_ticker_disable_interrupt(void)
+{
+    /* Disable compare channel interrupts */
+    TIMER_IntDisable(US_TICKER_TIMER, TIMER_IEN_CC0);
+}
+
+void us_ticker_clear_interrupt(void)
+{
+    /* Clear compare channel interrupts */
+    TIMER_IntClear(US_TICKER_TIMER, TIMER_IFC_CC0);
+}