mirror of https://github.com/ArduPilot/ardupilot
150 lines
4.3 KiB
C++
150 lines
4.3 KiB
C++
/*
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* This file is free software: you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This file is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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* See the GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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* Code by Andrew Tridgell and Siddharth Bharat Purohit
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*/
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#include "shared_dma.h"
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/*
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code to handle sharing of DMA channels between peripherals
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*/
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using namespace ChibiOS;
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Shared_DMA::dma_lock Shared_DMA::locks[SHARED_DMA_MAX_STREAM_ID];
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void Shared_DMA::init(void)
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{
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for (uint8_t i=0; i<SHARED_DMA_MAX_STREAM_ID; i++) {
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chBSemObjectInit(&locks[i].semaphore, false);
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}
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}
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// constructor
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Shared_DMA::Shared_DMA(uint8_t _stream_id1,
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uint8_t _stream_id2,
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dma_allocate_fn_t _allocate,
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dma_deallocate_fn_t _deallocate)
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{
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stream_id1 = _stream_id1;
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stream_id2 = _stream_id2;
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allocate = _allocate;
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deallocate = _deallocate;
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}
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//remove any assigned deallocator or allocator
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void Shared_DMA::unregister()
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{
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if (locks[stream_id1].obj == this) {
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locks[stream_id1].deallocate();
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locks[stream_id1].obj = nullptr;
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}
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if (locks[stream_id2].obj == this) {
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locks[stream_id2].deallocate();
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locks[stream_id2].obj = nullptr;
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}
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}
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// lock the DMA channels
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void Shared_DMA::lock(void)
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{
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if (stream_id1 != SHARED_DMA_NONE) {
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chBSemWait(&locks[stream_id1].semaphore);
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}
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if (stream_id2 != SHARED_DMA_NONE) {
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chBSemWait(&locks[stream_id2].semaphore);
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}
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// see if another driver has DMA allocated. If so, call their
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// deallocation function
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if (stream_id1 != SHARED_DMA_NONE &&
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locks[stream_id1].obj && locks[stream_id1].obj != this) {
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locks[stream_id1].deallocate();
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locks[stream_id1].obj = nullptr;
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}
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if (stream_id2 != SHARED_DMA_NONE &&
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locks[stream_id2].obj && locks[stream_id2].obj != this) {
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locks[stream_id2].deallocate();
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locks[stream_id2].obj = nullptr;
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}
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if ((stream_id1 != SHARED_DMA_NONE && locks[stream_id1].obj == nullptr) ||
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(stream_id2 != SHARED_DMA_NONE && locks[stream_id2].obj == nullptr)) {
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// allocate the DMA channels and put our deallocation function in place
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allocate();
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if (stream_id1 != SHARED_DMA_NONE) {
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locks[stream_id1].deallocate = deallocate;
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locks[stream_id1].obj = this;
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}
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if (stream_id2 != SHARED_DMA_NONE) {
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locks[stream_id2].deallocate = deallocate;
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locks[stream_id2].obj = this;
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}
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}
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have_lock = true;
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}
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// unlock the DMA channels
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void Shared_DMA::unlock(void)
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{
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osalDbgAssert(have_lock, "must have lock");
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if (stream_id2 != SHARED_DMA_NONE) {
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chBSemSignal(&locks[stream_id2].semaphore);
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}
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if (stream_id1 != SHARED_DMA_NONE) {
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chBSemSignal(&locks[stream_id1].semaphore);
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}
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have_lock = false;
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}
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// unlock the DMA channels from a lock zone
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void Shared_DMA::unlock_from_lockzone(void)
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{
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osalDbgAssert(have_lock, "must have lock");
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if (stream_id2 != SHARED_DMA_NONE) {
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chBSemSignalI(&locks[stream_id2].semaphore);
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chSchRescheduleS();
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}
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if (stream_id1 != SHARED_DMA_NONE) {
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chBSemSignalI(&locks[stream_id1].semaphore);
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chSchRescheduleS();
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}
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have_lock = false;
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}
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// unlock the DMA channels from an IRQ
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void Shared_DMA::unlock_from_IRQ(void)
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{
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osalDbgAssert(have_lock, "must have lock");
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chSysLockFromISR();
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if (stream_id2 != SHARED_DMA_NONE) {
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chBSemSignalI(&locks[stream_id2].semaphore);
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}
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if (stream_id1 != SHARED_DMA_NONE) {
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chBSemSignalI(&locks[stream_id1].semaphore);
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}
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have_lock = false;
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chSysUnlockFromISR();
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}
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/*
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lock all channels - used on reboot to ensure no sensor DMA is in
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progress
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*/
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void Shared_DMA::lock_all(void)
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{
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for (uint8_t i=0; i<SHARED_DMA_MAX_STREAM_ID; i++) {
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chBSemWait(&locks[i].semaphore);
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}
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}
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