Merge pull request #2297 from jepler/tick-refactor

Call background tasks only once per ms

1 files changed, 67 insertions, 0 deletions

diff --git a/supervisor/shared/tick.h b/supervisor/shared/tick.h
new file mode 100644
index 000000000..7ce8281ba
--- /dev/null
+++ b/supervisor/shared/tick.h
@@ -0,0 +1,67 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2019 Jeff Epler for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#ifndef __INCLUDED_SUPERVISOR_TICK_H
+#define __INCLUDED_SUPERVISOR_TICK_H
+
+#include <stdint.h>
+
+/** @brief To be called once every ms
+ *
+ * The port must call supervisor_tick once per millisecond to perform regular tasks.
+ * This is called from the SysTick interrupt or similar, and is safe to call in an
+ * interrupt context.
+ */
+extern void supervisor_tick(void);
+/** @brief Cause background tasks to be called soon
+ *
+ * Normally, background tasks are only run once per tick.  For other cases where
+ * an event noticed from an interrupt context needs to be completed by a background
+ * task activity, the interrupt can call supervisor_fake_tick.
+ */
+extern void supervisor_fake_tick(void);
+/** @brief Get the lower 32 bits of the time in milliseconds
+ *
+ * This can be more efficient than supervisor_ticks_ms64, for sites where a wraparound
+ * of ~49.5 days is not harmful.
+ */
+extern uint32_t supervisor_ticks_ms32(void);
+/** @brief Get the full time in milliseconds
+ *
+ * Because common ARM mcus cannot atomically work with 64-bit quantities, this
+ * function must briefly disable interrupts in order to return the value.  If
+ * only relative durations of less than about ~49.5 days need to be considered,
+ * then it may be possible to use supervisor_ticks_ms64 instead.
+ */
+extern uint64_t supervisor_ticks_ms64(void);
+/** @brief Run background ticks, but only about every millisecond.
+ *
+ * Normally, this is not called directly.  Instead use the RUN_BACKGROUND_TASKS
+ * macro.
+ */
+extern void supervisor_run_background_if_tick(void);
+
+#endif