Add tickless to some mbed-os devices

rtos/TARGET_CORTEX/mbed_rtx_conf.h

@@ -36,7 +36,7 @@
 
 #define OS_TIMER_THREAD_STACK_SIZE 768
 #ifndef OS_IDLE_THREAD_STACK_SIZE
-#define OS_IDLE_THREAD_STACK_SIZE  256
+#define OS_IDLE_THREAD_STACK_SIZE  512
 #endif
 
 #define OS_DYNAMIC_MEM_SIZE         0

rtos/TARGET_CORTEX/mbed_rtx_idle.cpp

@@ -0,0 +1,230 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2006-2012 ARM Limited
+ *
+ * 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.
+ */
+
+#include "rtos/rtos_idle.h"
+#include "platform/mbed_sleep.h"
+#include "TimerEvent.h"
+#include "lp_ticker_api.h"
+#include "core_cm.h"
+#include "mbed_critical.h"
+#include "mbed_assert.h"
+#include <new>
+#include "rtx_os.h"
+extern "C" {
+#include "rtx_lib.h"
+}
+
+using namespace mbed;
+
+#ifdef MBED_TICKLESS
+
+#if (defined(NO_SYSTICK))
+/**
+ * Return an IRQ number that can be used in the absence of SysTick
+ *
+ * @return Free IRQ number that can be used
+ */
+extern "C" IRQn_Type mbed_get_m0_tick_irqn(void);
+#endif
+
+class RtosTimer : private TimerEvent {
+public:
+    RtosTimer(): TimerEvent(get_lp_ticker_data()), _start_time(0), _tick(0) {
+        _start_time = ticker_read_us(_ticker_data);
+#if (defined(NO_SYSTICK))
+        NVIC_SetVector(mbed_get_m0_tick_irqn(), (uint32_t)SysTick_Handler);
+        NVIC_SetPriority(mbed_get_m0_tick_irqn(), 0xFF); /* RTOS requires lowest priority */
+        NVIC_EnableIRQ(mbed_get_m0_tick_irqn());
+#else
+        // Ensure SysTick has the correct priority as it is still used
+        // to trigger software interrupts on each tick. The period does
+        // not matter since it will never start counting.
+        SysTick_Setup(16);
+#endif
+    };
+
+    /**
+     * Schedule an os tick to fire
+     *
+     * @param delta Tick to fire at relative to current tick
+     */
+    void schedule_tick(uint32_t delta=1) {
+        insert_absolute(_start_time + (_tick + delta) * 1000000 /  OS_TICK_FREQ);
+    }
+
+
+    /**
+     * Prevent any scheduled ticks from triggering
+     */
+    void cancel_tick() {
+        remove();
+    }
+
+    /**
+     * Get the current tick count
+     *
+     * @return The number of ticks since boot. This should match RTX's tick count
+     */
+    uint32_t get_tick() {
+        return _tick & 0xFFFFFFFF;
+    }
+
+    /**
+     * Update the internal tick count
+     *
+     * @return The number of ticks incremented
+     */
+    uint32_t update_tick() {
+        uint64_t new_tick = ticker_read_us(_ticker_data) * OS_TICK_FREQ / 1000000;
+        if (new_tick > _tick) {
+            // Don't update to the current tick. Instead, update to the
+            // previous tick and let the SysTick handler increment it
+            // to the current value. This allows scheduling restart
+            // successfully after the OS is resumed.
+            new_tick--;
+        }
+        uint32_t elapsed_ticks = new_tick - _tick;
+        _tick = new_tick;
+        return elapsed_ticks;
+    }
+
+    /**
+     * Get the time
+     *
+     * @return Current time in microseconds
+     */
+    us_timestamp_t get_time() {
+        return ticker_read_us(_ticker_data);
+    }
+
+    ~RtosTimer() {
+
+    };
+
+protected:
+
+    void handler() {
+#if (defined(NO_SYSTICK))
+        NVIC_SetPendingIRQ(mbed_get_m0_tick_irqn());
+#else
+        SCB->ICSR = SCB_ICSR_PENDSTSET_Msk;
+#endif
+        _tick++;
+    }
+
+    us_timestamp_t _start_time;
+    uint64_t _tick;
+};
+
+static RtosTimer *os_timer;
+static uint64_t os_timer_data[sizeof(RtosTimer) / 8];
+
+/// Setup System Timer.
+int32_t osRtxSysTimerSetup (void)
+{
+    // Do not use SingletonPtr since this relies on the RTOS
+    if (NULL == os_timer) {
+        os_timer = new (os_timer_data) RtosTimer();
+    }
+    return -1;
+}
+
+/// Enable System Timer.
+void osRtxSysTimerEnable (void)
+{
+    // set to fire interrupt on next tick
+    os_timer->schedule_tick();
+}
+
+/// Disable System Timer.
+void osRtxSysTimerDisable (void)
+{
+    os_timer->cancel_tick();
+}
+
+/// Acknowledge System Timer IRQ.
+void osRtxSysTimerAckIRQ (void)
+{
+    os_timer->schedule_tick();
+}
+
+/// Get System Timer count.
+uint32_t osRtxSysTimerGetCount (void)
+{
+    return os_timer->get_time() & 0xFFFFFFFF;
+}
+
+static void default_idle_hook(void)
+{
+    uint32_t elapsed_ticks = 0;
+
+    core_util_critical_section_enter();
+    uint32_t ticks_to_sleep = svcRtxKernelSuspend();
+    MBED_ASSERT(os_timer->get_tick() == svcRtxKernelGetTickCount());
+    if (ticks_to_sleep) {
+        os_timer->schedule_tick(ticks_to_sleep);
+
+        sleep_manager_lock_deep_sleep();
+        sleep();
+        sleep_manager_unlock_deep_sleep();
+
+        os_timer->cancel_tick();
+        // calculate how long we slept
+        elapsed_ticks = os_timer->update_tick();
+    }
+    svcRtxKernelResume(elapsed_ticks);
+    core_util_critical_section_exit();
+}
+
+#else
+
+static void default_idle_hook(void)
+{
+    // critical section to complete sleep with locked deepsleep
+    core_util_critical_section_enter();
+    sleep_manager_lock_deep_sleep();
+    sleep();
+    sleep_manager_unlock_deep_sleep();
+    core_util_critical_section_exit();
+}
+
+#endif // MBED_TICKLESS
+
+static void (*idle_hook_fptr)(void) = &default_idle_hook;
+
+void rtos_attach_idle_hook(void (*fptr)(void))
+{
+    //Attach the specified idle hook, or the default idle hook in case of a NULL pointer
+    if (fptr != NULL) {
+        idle_hook_fptr = fptr;
+    } else {
+        idle_hook_fptr = default_idle_hook;
+    }
+}
+
+extern "C" void rtos_idle_loop(void)
+{
+    //Continuously call the idle hook function pointer
+    while (1) {
+        idle_hook_fptr();
+    }
+}