Import Mbed OS hard-float snapshot

targets/TARGET_ARM_SSG/TARGET_MUSCA_B1/us_ticker.c

@@ -0,0 +1,124 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2017-2019 Arm Limited
+ *
+ * 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.
+ */
+
+/**
+ * Supports the High-resolution Ticker for mbed by implementing
+ * \ref us_ticker_api.h, using a CMSDK Timer \ref timer_cmsdk_dev_t.
+ */
+
+#include "device.h"
+#include "mbed_critical.h"
+#include "timer_cmsdk_drv.h"
+#include "us_ticker_api.h"
+
+static uint64_t total_ticks = 0;
+/* Stores the last reload value, or the last tick value read when a read API
+ * call occurs from the upper layer, needed to keep total_ticks
+ * accumulated properly.
+ */
+static uint32_t previous_ticks = 0;
+
+static void restart_timer(uint32_t new_reload)
+{
+    timer_cmsdk_disable(&USEC_TIMER_DEV);
+    timer_cmsdk_set_reload_value(&USEC_TIMER_DEV,
+                                 new_reload);
+    timer_cmsdk_reset(&USEC_TIMER_DEV);
+    timer_cmsdk_clear_interrupt(&USEC_TIMER_DEV);
+    timer_cmsdk_enable_interrupt(&USEC_TIMER_DEV);
+    timer_cmsdk_enable(&USEC_TIMER_DEV);
+}
+
+static void update_ticker(void)
+{
+    if (timer_cmsdk_is_interrupt_active(&USEC_TIMER_DEV)) {
+        total_ticks += previous_ticks;
+        previous_ticks = TIMER_CMSDK_MAX_RELOAD;
+        restart_timer(previous_ticks);
+    } else {
+        uint32_t tick = timer_cmsdk_get_current_value(&USEC_TIMER_DEV);
+
+        if (tick < previous_ticks) {
+            uint32_t delta = previous_ticks - tick;
+            total_ticks += delta;
+            previous_ticks = tick;
+        }
+    }
+}
+
+void us_ticker_init(void)
+{
+    timer_cmsdk_init(&USEC_TIMER_DEV);
+    previous_ticks = TIMER_CMSDK_MAX_RELOAD;
+    NVIC_EnableIRQ(USEC_INTERVAL_IRQ);
+    restart_timer(previous_ticks);
+}
+
+void us_ticker_free(void)
+{
+    timer_cmsdk_disable(&USEC_TIMER_DEV);
+}
+
+uint32_t us_ticker_read(void)
+{
+    core_util_critical_section_enter();
+    update_ticker();
+    core_util_critical_section_exit();
+
+    return (uint32_t)(total_ticks >> USEC_REPORTED_SHIFT);
+}
+
+void us_ticker_set_interrupt(timestamp_t timestamp)
+{
+    uint32_t reload = (timestamp - us_ticker_read()) << USEC_REPORTED_SHIFT;
+    previous_ticks = reload;
+    restart_timer(previous_ticks);
+}
+
+void us_ticker_disable_interrupt(void)
+{
+    timer_cmsdk_disable_interrupt(&USEC_TIMER_DEV);
+}
+
+void us_ticker_clear_interrupt(void)
+{
+    timer_cmsdk_clear_interrupt(&USEC_TIMER_DEV);
+}
+
+void us_ticker_fire_interrupt(void)
+{
+    NVIC_SetPendingIRQ(USEC_INTERVAL_IRQ);
+}
+
+const ticker_info_t* us_ticker_get_info()
+{
+    static const ticker_info_t info = {
+        USEC_REPORTED_FREQ_HZ,
+        USEC_REPORTED_BITS
+    };
+    return &info;
+}
+
+#ifndef usec_interval_irq_handler
+#error "usec_interval_irq_handler should be defined, check device_cfg.h!"
+#endif
+void usec_interval_irq_handler(void)
+{
+    update_ticker();
+    us_ticker_irq_handler();
+}