mbed-os/rtos/Kernel.cpp

64 lines
2.8 KiB
C++

/* mbed Microcontroller Library
* Copyright (c) 2017 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/Kernel.h"
#include "mbed.h"
namespace rtos {
uint64_t Kernel::get_ms_count() {
// CMSIS-RTOS 2.1.0 and 2.1.1 differ in the time type. We assume
// our header at least matches the implementation, so we don't try looking
// at the run-time version report. (There's no compile-time version report)
// 2.1.0 uint64_t osKernelGetTickCount(void), not documented as callable from ISR (but RTX does allow)
// 2.1.1 uint32_t osKernelGetTickCount(void), callable from ISR
// 2.1.x who knows? We assume could go back to uint64_t
if (sizeof osKernelGetTickCount() == sizeof(uint64_t)) {
return osKernelGetTickCount();
} else /* assume 32-bit */ {
// Based on suggestion in CMSIS-RTOS 2.1.1 docs, but with reentrancy
// protection for the tick memory. We use critical section rather than a
// mutex, as hopefully this method can be callable from interrupt later -
// only thing currently preventing it is that pre CMSIS RTOS 2.1.1, it's
// not defined as safe.
// We assume this is called multiple times per 32-bit wrap period (49 days).
static uint32_t tick_h, tick_l;
core_util_critical_section_enter();
// The 2.1.1 API says this is legal from an ISR - we assume this means
// it's also legal with interrupts disabled. RTX implementation kind
// of conflates the two.
uint32_t tick32 = osKernelGetTickCount();
if (tick32 < tick_l) {
tick_h++;
}
tick_l = tick32;
uint64_t ret = ((uint64_t) tick_h << 32) | tick_l;
core_util_critical_section_exit();
return ret;
}
}
}