Kev Mann / mbed-dev-OS5_10_4

RTC auf true

platform/mbed_poll.cpp@0:38ceb79fef03, 2018-11-28 (annotated)

Committer:
kevman
Date:
Wed Nov 28 15:10:15 2018 +0000
Revision:
0:38ceb79fef03
RTC modified

Who changed what in which revision?

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kevman 0:38ceb79fef03 1 /* mbed Microcontroller Library
kevman 0:38ceb79fef03 2 * Copyright (c) 2017 ARM Limited
kevman 0:38ceb79fef03 3 *
kevman 0:38ceb79fef03 4 * Licensed under the Apache License, Version 2.0 (the "License");
kevman 0:38ceb79fef03 5 * you may not use this file except in compliance with the License.
kevman 0:38ceb79fef03 6 * You may obtain a copy of the License at
kevman 0:38ceb79fef03 7 *
kevman 0:38ceb79fef03 8 * http://www.apache.org/licenses/LICENSE-2.0
kevman 0:38ceb79fef03 9 *
kevman 0:38ceb79fef03 10 * Unless required by applicable law or agreed to in writing, software
kevman 0:38ceb79fef03 11 * distributed under the License is distributed on an "AS IS" BASIS,
kevman 0:38ceb79fef03 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
kevman 0:38ceb79fef03 13 * See the License for the specific language governing permissions and
kevman 0:38ceb79fef03 14 * limitations under the License.
kevman 0:38ceb79fef03 15 */
kevman 0:38ceb79fef03 16 #include "mbed_poll.h"
kevman 0:38ceb79fef03 17 #include "FileHandle.h"
kevman 0:38ceb79fef03 18 #if MBED_CONF_RTOS_PRESENT
kevman 0:38ceb79fef03 19 #include "rtos/Kernel.h"
kevman 0:38ceb79fef03 20 #include "rtos/Thread.h"
kevman 0:38ceb79fef03 21 using namespace rtos;
kevman 0:38ceb79fef03 22 #else
kevman 0:38ceb79fef03 23 #include "drivers/Timer.h"
kevman 0:38ceb79fef03 24 #include "drivers/LowPowerTimer.h"
kevman 0:38ceb79fef03 25 #endif
kevman 0:38ceb79fef03 26
kevman 0:38ceb79fef03 27 namespace mbed {
kevman 0:38ceb79fef03 28
kevman 0:38ceb79fef03 29 // timeout -1 forever, or milliseconds
kevman 0:38ceb79fef03 30 int poll(pollfh fhs[], unsigned nfhs, int timeout)
kevman 0:38ceb79fef03 31 {
kevman 0:38ceb79fef03 32 /*
kevman 0:38ceb79fef03 33 * TODO Proper wake-up mechanism.
kevman 0:38ceb79fef03 34 * In order to correctly detect availability of read/write a FileHandle, we needed
kevman 0:38ceb79fef03 35 * a select or poll mechanisms. We opted for poll as POSIX defines in
kevman 0:38ceb79fef03 36 * http://pubs.opengroup.org/onlinepubs/009695399/functions/poll.html Currently,
kevman 0:38ceb79fef03 37 * mbed::poll() just spins and scans filehandles looking for any events we are
kevman 0:38ceb79fef03 38 * interested in. In future, his spinning behaviour will be replaced with
kevman 0:38ceb79fef03 39 * condition variables.
kevman 0:38ceb79fef03 40 */
kevman 0:38ceb79fef03 41 #if MBED_CONF_RTOS_PRESENT
kevman 0:38ceb79fef03 42 uint64_t start_time = 0;
kevman 0:38ceb79fef03 43 if (timeout > 0) {
kevman 0:38ceb79fef03 44 start_time = Kernel::get_ms_count();
kevman 0:38ceb79fef03 45 }
kevman 0:38ceb79fef03 46 #define TIME_ELAPSED() int64_t(Kernel::get_ms_count() - start_time)
kevman 0:38ceb79fef03 47 #else
kevman 0:38ceb79fef03 48 #if MBED_CONF_PLATFORM_POLL_USE_LOWPOWER_TIMER
kevman 0:38ceb79fef03 49 LowPowerTimer timer;
kevman 0:38ceb79fef03 50 #else
kevman 0:38ceb79fef03 51 Timer timer;
kevman 0:38ceb79fef03 52 #endif
kevman 0:38ceb79fef03 53 if (timeout > 0) {
kevman 0:38ceb79fef03 54 timer.start();
kevman 0:38ceb79fef03 55 }
kevman 0:38ceb79fef03 56 #define TIME_ELAPSED() timer.read_ms()
kevman 0:38ceb79fef03 57 #endif // MBED_CONF_RTOS_PRESENT
kevman 0:38ceb79fef03 58
kevman 0:38ceb79fef03 59 int count = 0;
kevman 0:38ceb79fef03 60 for (;;) {
kevman 0:38ceb79fef03 61 /* Scan the file handles */
kevman 0:38ceb79fef03 62 for (unsigned n = 0; n < nfhs; n++) {
kevman 0:38ceb79fef03 63 FileHandle *fh = fhs[n].fh;
kevman 0:38ceb79fef03 64 short mask = fhs[n].events | POLLERR | POLLHUP | POLLNVAL;
kevman 0:38ceb79fef03 65 if (fh) {
kevman 0:38ceb79fef03 66 fhs[n].revents = fh->poll(mask) & mask;
kevman 0:38ceb79fef03 67 } else {
kevman 0:38ceb79fef03 68 fhs[n].revents = POLLNVAL;
kevman 0:38ceb79fef03 69 }
kevman 0:38ceb79fef03 70 if (fhs[n].revents) {
kevman 0:38ceb79fef03 71 count++;
kevman 0:38ceb79fef03 72 }
kevman 0:38ceb79fef03 73 }
kevman 0:38ceb79fef03 74
kevman 0:38ceb79fef03 75 if (count) {
kevman 0:38ceb79fef03 76 break;
kevman 0:38ceb79fef03 77 }
kevman 0:38ceb79fef03 78
kevman 0:38ceb79fef03 79 /* Nothing selected - this is where timeout handling would be needed */
kevman 0:38ceb79fef03 80 if (timeout == 0 || (timeout > 0 && TIME_ELAPSED() > timeout)) {
kevman 0:38ceb79fef03 81 break;
kevman 0:38ceb79fef03 82 }
kevman 0:38ceb79fef03 83 #ifdef MBED_CONF_RTOS_PRESENT
kevman 0:38ceb79fef03 84 // TODO - proper blocking
kevman 0:38ceb79fef03 85 // wait for condition variable, wait queue whatever here
kevman 0:38ceb79fef03 86 rtos::Thread::wait(1);
kevman 0:38ceb79fef03 87 #endif
kevman 0:38ceb79fef03 88 }
kevman 0:38ceb79fef03 89 return count;
kevman 0:38ceb79fef03 90 }
kevman 0:38ceb79fef03 91
kevman 0:38ceb79fef03 92 } // namespace mbed