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HAL_ChibiOS: fixed 3-way DMA sharing bug

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when we have 3 way contention across two DMA streams we could get the
dma_deallocate function called in an object from two places at
once. This adds a mutex that prevents that scenario
This commit is contained in:
Andrew Tridgell 2018-06-04 21:27:54 +10:00
parent 0e09dc75c0
commit a945c97ec6
4 changed files with 21 additions and 0 deletions
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5
libraries/AP_HAL_ChibiOS/I2CDevice.cpp
View File

@ -53,6 +53,7 @@ I2CBus I2CDeviceManager::businfo[ARRAY_SIZE_SIMPLE(I2CD)];
// get a handle for DMA sharing DMA channels with other subsystems
void I2CBus::dma_init(void)
{
chMtxObjectInit(&dma_lock);
dma_handle = new Shared_DMA(I2CD[busnum].dma_channel_tx, I2CD[busnum].dma_channel_rx,
FUNCTOR_BIND_MEMBER(&I2CBus::dma_allocate, void, Shared_DMA *),
FUNCTOR_BIND_MEMBER(&I2CBus::dma_deallocate, void, Shared_DMA *));
@ -163,12 +164,14 @@ I2CDevice::~I2CDevice()
*/
void I2CBus::dma_allocate(Shared_DMA *ctx)
{
chMtxLock(&dma_lock);
if (!i2c_started) {
osalDbgAssert(I2CD[busnum].i2c->state == I2C_STOP, "i2cStart state");
i2cStart(I2CD[busnum].i2c, &i2ccfg);
osalDbgAssert(I2CD[busnum].i2c->state == I2C_READY, "i2cStart state");
i2c_started = true;
}
chMtxUnlock(&dma_lock);
}
/*
@ -176,12 +179,14 @@ void I2CBus::dma_allocate(Shared_DMA *ctx)
*/
void I2CBus::dma_deallocate(Shared_DMA *)
{
chMtxLock(&dma_lock);
if (i2c_started) {
osalDbgAssert(I2CD[busnum].i2c->state == I2C_READY, "i2cStart state");
i2cStop(I2CD[busnum].i2c);
osalDbgAssert(I2CD[busnum].i2c->state == I2C_STOP, "i2cStart state");
i2c_started = false;
}
chMtxUnlock(&dma_lock);
}
bool I2CDevice::transfer(const uint8_t *send, uint32_t send_len,

6
libraries/AP_HAL_ChibiOS/I2CDevice.h
View File

@ -39,6 +39,12 @@ public:
uint32_t busclock;
bool i2c_started;
bool i2c_active;
// we need an additional lock in the dma_allocate and
// dma_deallocate functions to cope with 3-way contention as we
// have two DMA channels that we are handling with the shared_dma
// code
mutex_t dma_lock;
void dma_allocate(Shared_DMA *);
void dma_deallocate(Shared_DMA *);

4
libraries/AP_HAL_ChibiOS/SPIDevice.cpp
View File

@ -61,6 +61,8 @@ SPIBus::SPIBus(uint8_t _bus) :
DeviceBus(APM_SPI_PRIORITY),
bus(_bus)
{
chMtxObjectInit(&dma_lock);
// allow for sharing of DMA channels with other peripherals
dma_handle = new Shared_DMA(spi_devices[bus].dma_channel_rx,
spi_devices[bus].dma_channel_tx,
@ -82,11 +84,13 @@ void SPIBus::dma_allocate(Shared_DMA *ctx)
*/
void SPIBus::dma_deallocate(Shared_DMA *ctx)
{
chMtxLock(&dma_lock);
// another non-SPI peripheral wants one of our DMA channels
if (spi_started) {
spiStop(spi_devices[bus].driver);
spi_started = false;
}
chMtxUnlock(&dma_lock);
}

6
libraries/AP_HAL_ChibiOS/SPIDevice.h
View File

@ -34,6 +34,12 @@ public:
void dma_allocate(Shared_DMA *ctx);
void dma_deallocate(Shared_DMA *ctx);
bool spi_started;
// we need an additional lock in the dma_allocate and
// dma_deallocate functions to cope with 3-way contention as we
// have two DMA channels that we are handling with the shared_dma
// code
mutex_t dma_lock;
};
struct SPIDesc {