ardupilot/libraries/AP_HAL_ChibiOS/shared_dma.cpp

150 lines
4.3 KiB
C++

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