Nicolas Borla / Mbed OS BBR_1Ebene

BBR 1 Ebene

mbed-os/platform/mbed_poll.cpp@0:fbdae7e6d805, 2018-05-14 (annotated)

Committer:
borlanic
Date:
Mon May 14 11:29:06 2018 +0000
Revision:
0:fbdae7e6d805
BBR

Who changed what in which revision?

UserRevisionLine numberNew contents of line
borlanic 0:fbdae7e6d805 1 /* mbed Microcontroller Library
borlanic 0:fbdae7e6d805 2 * Copyright (c) 2017 ARM Limited
borlanic 0:fbdae7e6d805 3 *
borlanic 0:fbdae7e6d805 4 * Licensed under the Apache License, Version 2.0 (the "License");
borlanic 0:fbdae7e6d805 5 * you may not use this file except in compliance with the License.
borlanic 0:fbdae7e6d805 6 * You may obtain a copy of the License at
borlanic 0:fbdae7e6d805 7 *
borlanic 0:fbdae7e6d805 8 * http://www.apache.org/licenses/LICENSE-2.0
borlanic 0:fbdae7e6d805 9 *
borlanic 0:fbdae7e6d805 10 * Unless required by applicable law or agreed to in writing, software
borlanic 0:fbdae7e6d805 11 * distributed under the License is distributed on an "AS IS" BASIS,
borlanic 0:fbdae7e6d805 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
borlanic 0:fbdae7e6d805 13 * See the License for the specific language governing permissions and
borlanic 0:fbdae7e6d805 14 * limitations under the License.
borlanic 0:fbdae7e6d805 15 */
borlanic 0:fbdae7e6d805 16 #include "mbed_poll.h"
borlanic 0:fbdae7e6d805 17 #include "FileHandle.h"
borlanic 0:fbdae7e6d805 18 #if MBED_CONF_RTOS_PRESENT
borlanic 0:fbdae7e6d805 19 #include "rtos/Kernel.h"
borlanic 0:fbdae7e6d805 20 #include "rtos/Thread.h"
borlanic 0:fbdae7e6d805 21 using namespace rtos;
borlanic 0:fbdae7e6d805 22 #else
borlanic 0:fbdae7e6d805 23 #include "Timer.h"
borlanic 0:fbdae7e6d805 24 #include "LowPowerTimer.h"
borlanic 0:fbdae7e6d805 25 #endif
borlanic 0:fbdae7e6d805 26
borlanic 0:fbdae7e6d805 27 namespace mbed {
borlanic 0:fbdae7e6d805 28
borlanic 0:fbdae7e6d805 29 // timeout -1 forever, or milliseconds
borlanic 0:fbdae7e6d805 30 int poll(pollfh fhs[], unsigned nfhs, int timeout)
borlanic 0:fbdae7e6d805 31 {
borlanic 0:fbdae7e6d805 32 /**
borlanic 0:fbdae7e6d805 33 * TODO Proper wake-up mechanism.
borlanic 0:fbdae7e6d805 34 * In order to correctly detect availability of read/write a FileHandle, we needed
borlanic 0:fbdae7e6d805 35 * a select or poll mechanisms. We opted for poll as POSIX defines in
borlanic 0:fbdae7e6d805 36 * http://pubs.opengroup.org/onlinepubs/009695399/functions/poll.html Currently,
borlanic 0:fbdae7e6d805 37 * mbed::poll() just spins and scans filehandles looking for any events we are
borlanic 0:fbdae7e6d805 38 * interested in. In future, his spinning behaviour will be replaced with
borlanic 0:fbdae7e6d805 39 * condition variables.
borlanic 0:fbdae7e6d805 40 */
borlanic 0:fbdae7e6d805 41 #if MBED_CONF_RTOS_PRESENT
borlanic 0:fbdae7e6d805 42 uint64_t start_time = 0;
borlanic 0:fbdae7e6d805 43 if (timeout > 0) {
borlanic 0:fbdae7e6d805 44 start_time = Kernel::get_ms_count();
borlanic 0:fbdae7e6d805 45 }
borlanic 0:fbdae7e6d805 46 #define TIME_ELAPSED() int64_t(Kernel::get_ms_count() - start_time)
borlanic 0:fbdae7e6d805 47 #else
borlanic 0:fbdae7e6d805 48 #if MBED_CONF_PLATFORM_POLL_USE_LOWPOWER_TIMER
borlanic 0:fbdae7e6d805 49 LowPowerTimer timer;
borlanic 0:fbdae7e6d805 50 #else
borlanic 0:fbdae7e6d805 51 Timer timer;
borlanic 0:fbdae7e6d805 52 #endif
borlanic 0:fbdae7e6d805 53 if (timeout > 0) {
borlanic 0:fbdae7e6d805 54 timer.start();
borlanic 0:fbdae7e6d805 55 }
borlanic 0:fbdae7e6d805 56 #define TIME_ELAPSED() timer.read_ms()
borlanic 0:fbdae7e6d805 57 #endif // MBED_CONF_RTOS_PRESENT
borlanic 0:fbdae7e6d805 58
borlanic 0:fbdae7e6d805 59 int count = 0;
borlanic 0:fbdae7e6d805 60 for (;;) {
borlanic 0:fbdae7e6d805 61 /* Scan the file handles */
borlanic 0:fbdae7e6d805 62 for (unsigned n = 0; n < nfhs; n++) {
borlanic 0:fbdae7e6d805 63 FileHandle *fh = fhs[n].fh;
borlanic 0:fbdae7e6d805 64 short mask = fhs[n].events | POLLERR | POLLHUP | POLLNVAL;
borlanic 0:fbdae7e6d805 65 if (fh) {
borlanic 0:fbdae7e6d805 66 fhs[n].revents = fh->poll(mask) & mask;
borlanic 0:fbdae7e6d805 67 } else {
borlanic 0:fbdae7e6d805 68 fhs[n].revents = POLLNVAL;
borlanic 0:fbdae7e6d805 69 }
borlanic 0:fbdae7e6d805 70 if (fhs[n].revents) {
borlanic 0:fbdae7e6d805 71 count++;
borlanic 0:fbdae7e6d805 72 }
borlanic 0:fbdae7e6d805 73 }
borlanic 0:fbdae7e6d805 74
borlanic 0:fbdae7e6d805 75 if (count) {
borlanic 0:fbdae7e6d805 76 break;
borlanic 0:fbdae7e6d805 77 }
borlanic 0:fbdae7e6d805 78
borlanic 0:fbdae7e6d805 79 /* Nothing selected - this is where timeout handling would be needed */
borlanic 0:fbdae7e6d805 80 if (timeout == 0 || (timeout > 0 && TIME_ELAPSED() > timeout)) {
borlanic 0:fbdae7e6d805 81 break;
borlanic 0:fbdae7e6d805 82 }
borlanic 0:fbdae7e6d805 83 #ifdef MBED_CONF_RTOS_PRESENT
borlanic 0:fbdae7e6d805 84 // TODO - proper blocking
borlanic 0:fbdae7e6d805 85 // wait for condition variable, wait queue whatever here
borlanic 0:fbdae7e6d805 86 rtos::Thread::wait(1);
borlanic 0:fbdae7e6d805 87 #endif
borlanic 0:fbdae7e6d805 88 }
borlanic 0:fbdae7e6d805 89 return count;
borlanic 0:fbdae7e6d805 90 }
borlanic 0:fbdae7e6d805 91
borlanic 0:fbdae7e6d805 92 } // namespace mbed